diff options
Diffstat (limited to 'Documentation/driver-api')
-rw-r--r-- | Documentation/driver-api/media/camera-sensor.rst | 134 | ||||
-rw-r--r-- | Documentation/driver-api/media/cec-core.rst | 62 | ||||
-rw-r--r-- | Documentation/driver-api/media/csi2.rst | 2 | ||||
-rw-r--r-- | Documentation/driver-api/media/drivers/index.rst | 2 | ||||
-rw-r--r-- | Documentation/driver-api/media/drivers/v4l-drivers/zoran.rst | 575 | ||||
-rw-r--r-- | Documentation/driver-api/media/drivers/vidtv.rst | 425 | ||||
-rw-r--r-- | Documentation/driver-api/media/index.rst | 1 | ||||
-rw-r--r-- | Documentation/driver-api/media/v4l2-subdev.rst | 97 |
8 files changed, 1216 insertions, 82 deletions
diff --git a/Documentation/driver-api/media/camera-sensor.rst b/Documentation/driver-api/media/camera-sensor.rst new file mode 100644 index 000000000000..4d1ae12b9b4d --- /dev/null +++ b/Documentation/driver-api/media/camera-sensor.rst @@ -0,0 +1,134 @@ +.. SPDX-License-Identifier: GPL-2.0 + +Writing camera sensor drivers +============================= + +CSI-2 +----- + +Please see what is written on :ref:`MIPI_CSI_2`. + +Handling clocks +--------------- + +Camera sensors have an internal clock tree including a PLL and a number of +divisors. The clock tree is generally configured by the driver based on a few +input parameters that are specific to the hardware:: the external clock frequency +and the link frequency. The two parameters generally are obtained from system +firmware. No other frequencies should be used in any circumstances. + +The reason why the clock frequencies are so important is that the clock signals +come out of the SoC, and in many cases a specific frequency is designed to be +used in the system. Using another frequency may cause harmful effects +elsewhere. Therefore only the pre-determined frequencies are configurable by the +user. + +Frame size +---------- + +There are two distinct ways to configure the frame size produced by camera +sensors. + +Freely configurable camera sensor drivers +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Freely configurable camera sensor drivers expose the device's internal +processing pipeline as one or more sub-devices with different cropping and +scaling configurations. The output size of the device is the result of a series +of cropping and scaling operations from the device's pixel array's size. + +An example of such a driver is the smiapp driver (see drivers/media/i2c/smiapp). + +Register list based drivers +~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Register list based drivers generally, instead of able to configure the device +they control based on user requests, are limited to a number of preset +configurations that combine a number of different parameters that on hardware +level are independent. How a driver picks such configuration is based on the +format set on a source pad at the end of the device's internal pipeline. + +Most sensor drivers are implemented this way, see e.g. +drivers/media/i2c/imx319.c for an example. + +Frame interval configuration +---------------------------- + +There are two different methods for obtaining possibilities for different frame +intervals as well as configuring the frame interval. Which one to implement +depends on the type of the device. + +Raw camera sensors +~~~~~~~~~~~~~~~~~~ + +Instead of a high level parameter such as frame interval, the frame interval is +a result of the configuration of a number of camera sensor implementation +specific parameters. Luckily, these parameters tend to be the same for more or +less all modern raw camera sensors. + +The frame interval is calculated using the following equation:: + + frame interval = (analogue crop width + horizontal blanking) * + (analogue crop height + vertical blanking) / pixel rate + +The formula is bus independent and is applicable for raw timing parameters on +large variety of devices beyond camera sensors. Devices that have no analogue +crop, use the full source image size, i.e. pixel array size. + +Horizontal and vertical blanking are specified by ``V4L2_CID_HBLANK`` and +``V4L2_CID_VBLANK``, respectively. The unit of these controls are lines. The +pixel rate is specified by ``V4L2_CID_PIXEL_RATE`` in the same sub-device. The +unit of that control is Hz. + +Register list based drivers need to implement read-only sub-device nodes for the +purpose. Devices that are not register list based need these to configure the +device's internal processing pipeline. + +The first entity in the linear pipeline is the pixel array. The pixel array may +be followed by other entities that are there to allow configuring binning, +skipping, scaling or digital crop :ref:`v4l2-subdev-selections`. + +USB cameras etc. devices +~~~~~~~~~~~~~~~~~~~~~~~~ + +USB video class hardware, as well as many cameras offering a similar higher +level interface natively, generally use the concept of frame interval (or frame +rate) on device level in firmware or hardware. This means lower level controls +implemented by raw cameras may not be used on uAPI (or even kAPI) to control the +frame interval on these devices. + +Power management +---------------- + +Always use runtime PM to manage the power states of your device. Camera sensor +drivers are in no way special in this respect: they are responsible for +controlling the power state of the device they otherwise control as well. In +general, the device must be powered on at least when its registers are being +accessed and when it is streaming. + +Existing camera sensor drivers may rely on the old +:c:type:`v4l2_subdev_core_ops`->s_power() callback for bridge or ISP drivers to +manage their power state. This is however **deprecated**. If you feel you need +to begin calling an s_power from an ISP or a bridge driver, instead please add +runtime PM support to the sensor driver you are using. Likewise, new drivers +should not use s_power. + +Please see examples in e.g. ``drivers/media/i2c/ov8856.c`` and +``drivers/media/i2c/smiapp/smiapp-core.c``. The two drivers work in both ACPI +and DT based systems. + +Control framework +~~~~~~~~~~~~~~~~~ + +``v4l2_ctrl_handler_setup()`` function may not be used in the device's runtime +PM ``runtime_resume`` callback, as it has no way to figure out the power state +of the device. This is because the power state of the device is only changed +after the power state transition has taken place. The ``s_ctrl`` callback can be +used to obtain device's power state after the power state transition: + +.. c:function:: + int pm_runtime_get_if_in_use(struct device *dev); + +The function returns a non-zero value if it succeeded getting the power count or +runtime PM was disabled, in either of which cases the driver may proceed to +access the device. diff --git a/Documentation/driver-api/media/cec-core.rst b/Documentation/driver-api/media/cec-core.rst index 3ce26b7c2b2b..03016eeaf8f4 100644 --- a/Documentation/driver-api/media/cec-core.rst +++ b/Documentation/driver-api/media/cec-core.rst @@ -36,8 +36,9 @@ The struct cec_adapter represents the CEC adapter hardware. It is created by calling cec_allocate_adapter() and deleted by calling cec_delete_adapter(): .. c:function:: - struct cec_adapter *cec_allocate_adapter(const struct cec_adap_ops *ops, void *priv, - const char *name, u32 caps, u8 available_las); + struct cec_adapter *cec_allocate_adapter(const struct cec_adap_ops *ops, \ + void *priv, const char *name, \ + u32 caps, u8 available_las); .. c:function:: void cec_delete_adapter(struct cec_adapter *adap); @@ -74,7 +75,8 @@ To register the /dev/cecX device node and the remote control device (if CEC_CAP_RC is set) you call: .. c:function:: - int cec_register_adapter(struct cec_adapter *adap, struct device *parent); + int cec_register_adapter(struct cec_adapter *adap, \ + struct device *parent); where parent is the parent device. @@ -123,9 +125,8 @@ The seven low-level ops deal with various aspects of controlling the CEC adapter hardware: -To enable/disable the hardware: +To enable/disable the hardware:: -.. c:function:: int (*adap_enable)(struct cec_adapter *adap, bool enable); This callback enables or disables the CEC hardware. Enabling the CEC hardware @@ -137,9 +138,8 @@ state of the CEC adapter after calling cec_allocate_adapter() is disabled. Note that adap_enable must return 0 if enable is false. -To enable/disable the 'monitor all' mode: +To enable/disable the 'monitor all' mode:: -.. c:function:: int (*adap_monitor_all_enable)(struct cec_adapter *adap, bool enable); If enabled, then the adapter should be put in a mode to also monitor messages @@ -150,9 +150,8 @@ called if the CEC_CAP_MONITOR_ALL capability is set. This callback is optional Note that adap_monitor_all_enable must return 0 if enable is false. -To enable/disable the 'monitor pin' mode: +To enable/disable the 'monitor pin' mode:: -.. c:function:: int (*adap_monitor_pin_enable)(struct cec_adapter *adap, bool enable); If enabled, then the adapter should be put in a mode to also monitor CEC pin @@ -163,9 +162,8 @@ the CEC_CAP_MONITOR_PIN capability is set. This callback is optional Note that adap_monitor_pin_enable must return 0 if enable is false. -To program a new logical address: +To program a new logical address:: -.. c:function:: int (*adap_log_addr)(struct cec_adapter *adap, u8 logical_addr); If logical_addr == CEC_LOG_ADDR_INVALID then all programmed logical addresses @@ -177,9 +175,8 @@ can receive directed messages to that address. Note that adap_log_addr must return 0 if logical_addr is CEC_LOG_ADDR_INVALID. -To transmit a new message: +To transmit a new message:: -.. c:function:: int (*adap_transmit)(struct cec_adapter *adap, u8 attempts, u32 signal_free_time, struct cec_msg *msg); @@ -196,17 +193,15 @@ The CEC_FREE_TIME_TO_USEC macro can be used to convert signal_free_time to microseconds (one data bit period is 2.4 ms). -To log the current CEC hardware status: +To log the current CEC hardware status:: -.. c:function:: void (*adap_status)(struct cec_adapter *adap, struct seq_file *file); This optional callback can be used to show the status of the CEC hardware. The status is available through debugfs: cat /sys/kernel/debug/cec/cecX/status -To free any resources when the adapter is deleted: +To free any resources when the adapter is deleted:: -.. c:function:: void (*adap_free)(struct cec_adapter *adap); This optional callback can be used to free any resources that might have been @@ -216,15 +211,14 @@ allocated by the driver. It's called from cec_delete_adapter. Your adapter driver will also have to react to events (typically interrupt driven) by calling into the framework in the following situations: -When a transmit finished (successfully or otherwise): +When a transmit finished (successfully or otherwise):: -.. c:function:: - void cec_transmit_done(struct cec_adapter *adap, u8 status, u8 arb_lost_cnt, - u8 nack_cnt, u8 low_drive_cnt, u8 error_cnt); + void cec_transmit_done(struct cec_adapter *adap, u8 status, + u8 arb_lost_cnt, u8 nack_cnt, u8 low_drive_cnt, + u8 error_cnt); -or: +or:: -.. c:function:: void cec_transmit_attempt_done(struct cec_adapter *adap, u8 status); The status can be one of: @@ -341,17 +335,15 @@ So this must work: $ cat einj.txt >error-inj The first callback is called when this file is read and it should show the -the current error injection state: +the current error injection state:: -.. c:function:: int (*error_inj_show)(struct cec_adapter *adap, struct seq_file *sf); It is recommended that it starts with a comment block with basic usage information. It returns 0 for success and an error otherwise. -The second callback will parse commands written to the ``error-inj`` file: +The second callback will parse commands written to the ``error-inj`` file:: -.. c:function:: bool (*error_inj_parse_line)(struct cec_adapter *adap, char *line); The ``line`` argument points to the start of the command. Any leading @@ -382,9 +374,8 @@ CEC protocol driven. The following high-level callbacks are available: }; The received() callback allows the driver to optionally handle a newly -received CEC message +received CEC message:: -.. c:function:: int (*received)(struct cec_adapter *adap, struct cec_msg *msg); If the driver wants to process a CEC message, then it can implement this @@ -399,15 +390,14 @@ CEC framework functions CEC Adapter drivers can call the following CEC framework functions: .. c:function:: - int cec_transmit_msg(struct cec_adapter *adap, struct cec_msg *msg, - bool block); + int cec_transmit_msg(struct cec_adapter *adap, struct cec_msg *msg, \ + bool block); Transmit a CEC message. If block is true, then wait until the message has been transmitted, otherwise just queue it and return. .. c:function:: - void cec_s_phys_addr(struct cec_adapter *adap, u16 phys_addr, - bool block); + void cec_s_phys_addr(struct cec_adapter *adap, u16 phys_addr, bool block); Change the physical address. This function will set adap->phys_addr and send an event if it has changed. If cec_s_log_addrs() has been called and @@ -422,15 +412,15 @@ to another valid physical address, then this function will first set the address to CEC_PHYS_ADDR_INVALID before enabling the new physical address. .. c:function:: - void cec_s_phys_addr_from_edid(struct cec_adapter *adap, - const struct edid *edid); + void cec_s_phys_addr_from_edid(struct cec_adapter *adap, \ + const struct edid *edid); A helper function that extracts the physical address from the edid struct and calls cec_s_phys_addr() with that address, or CEC_PHYS_ADDR_INVALID if the EDID did not contain a physical address or edid was a NULL pointer. .. c:function:: - int cec_s_log_addrs(struct cec_adapter *adap, + int cec_s_log_addrs(struct cec_adapter *adap, \ struct cec_log_addrs *log_addrs, bool block); Claim the CEC logical addresses. Should never be called if CEC_CAP_LOG_ADDRS diff --git a/Documentation/driver-api/media/csi2.rst b/Documentation/driver-api/media/csi2.rst index 17cad435f1a0..e1b838014906 100644 --- a/Documentation/driver-api/media/csi2.rst +++ b/Documentation/driver-api/media/csi2.rst @@ -1,5 +1,7 @@ .. SPDX-License-Identifier: GPL-2.0 +.. _MIPI_CSI_2: + MIPI CSI-2 ========== diff --git a/Documentation/driver-api/media/drivers/index.rst b/Documentation/driver-api/media/drivers/index.rst index 0df85fc96605..eb7011782863 100644 --- a/Documentation/driver-api/media/drivers/index.rst +++ b/Documentation/driver-api/media/drivers/index.rst @@ -25,6 +25,7 @@ Video4Linux (V4L) drivers sh_mobile_ceu_camera tuners vimc-devel + zoran Digital TV drivers @@ -35,4 +36,5 @@ Digital TV drivers dvb-usb frontends + vidtv contributors diff --git a/Documentation/driver-api/media/drivers/v4l-drivers/zoran.rst b/Documentation/driver-api/media/drivers/v4l-drivers/zoran.rst new file mode 100644 index 000000000000..83cbae9cedef --- /dev/null +++ b/Documentation/driver-api/media/drivers/v4l-drivers/zoran.rst @@ -0,0 +1,575 @@ +.. SPDX-License-Identifier: GPL-2.0 + +The Zoran driver +================ + +unified zoran driver (zr360x7, zoran, buz, dc10(+), dc30(+), lml33) + +website: http://mjpeg.sourceforge.net/driver-zoran/ + + +Frequently Asked Questions +-------------------------- + +What cards are supported +------------------------ + +Iomega Buz, Linux Media Labs LML33/LML33R10, Pinnacle/Miro +DC10/DC10+/DC30/DC30+ and related boards (available under various names). + +Iomega Buz +~~~~~~~~~~ + +* Zoran zr36067 PCI controller +* Zoran zr36060 MJPEG codec +* Philips saa7111 TV decoder +* Philips saa7185 TV encoder + +Drivers to use: videodev, i2c-core, i2c-algo-bit, +videocodec, saa7111, saa7185, zr36060, zr36067 + +Inputs/outputs: Composite and S-video + +Norms: PAL, SECAM (720x576 @ 25 fps), NTSC (720x480 @ 29.97 fps) + +Card number: 7 + +AverMedia 6 Eyes AVS6EYES +~~~~~~~~~~~~~~~~~~~~~~~~~ + +* Zoran zr36067 PCI controller +* Zoran zr36060 MJPEG codec +* Samsung ks0127 TV decoder +* Conexant bt866 TV encoder + +Drivers to use: videodev, i2c-core, i2c-algo-bit, +videocodec, ks0127, bt866, zr36060, zr36067 + +Inputs/outputs: + Six physical inputs. 1-6 are composite, + 1-2, 3-4, 5-6 doubles as S-video, + 1-3 triples as component. + One composite output. + +Norms: PAL, SECAM (720x576 @ 25 fps), NTSC (720x480 @ 29.97 fps) + +Card number: 8 + +.. note:: + + Not autodetected, card=8 is necessary. + +Linux Media Labs LML33 +~~~~~~~~~~~~~~~~~~~~~~ + +* Zoran zr36067 PCI controller +* Zoran zr36060 MJPEG codec +* Brooktree bt819 TV decoder +* Brooktree bt856 TV encoder + +Drivers to use: videodev, i2c-core, i2c-algo-bit, +videocodec, bt819, bt856, zr36060, zr36067 + +Inputs/outputs: Composite and S-video + +Norms: PAL (720x576 @ 25 fps), NTSC (720x480 @ 29.97 fps) + +Card number: 5 + +Linux Media Labs LML33R10 +~~~~~~~~~~~~~~~~~~~~~~~~~ + +* Zoran zr36067 PCI controller +* Zoran zr36060 MJPEG codec +* Philips saa7114 TV decoder +* Analog Devices adv7170 TV encoder + +Drivers to use: videodev, i2c-core, i2c-algo-bit, +videocodec, saa7114, adv7170, zr36060, zr36067 + +Inputs/outputs: Composite and S-video + +Norms: PAL (720x576 @ 25 fps), NTSC (720x480 @ 29.97 fps) + +Card number: 6 + +Pinnacle/Miro DC10(new) +~~~~~~~~~~~~~~~~~~~~~~~ + +* Zoran zr36057 PCI controller +* Zoran zr36060 MJPEG codec +* Philips saa7110a TV decoder +* Analog Devices adv7176 TV encoder + +Drivers to use: videodev, i2c-core, i2c-algo-bit, +videocodec, saa7110, adv7175, zr36060, zr36067 + +Inputs/outputs: Composite, S-video and Internal + +Norms: PAL, SECAM (768x576 @ 25 fps), NTSC (640x480 @ 29.97 fps) + +Card number: 1 + +Pinnacle/Miro DC10+ +~~~~~~~~~~~~~~~~~~~ + +* Zoran zr36067 PCI controller +* Zoran zr36060 MJPEG codec +* Philips saa7110a TV decoder +* Analog Devices adv7176 TV encoder + +Drivers to use: videodev, i2c-core, i2c-algo-bit, +videocodec, saa7110, adv7175, zr36060, zr36067 + +Inputs/outputs: Composite, S-video and Internal + +Norms: PAL, SECAM (768x576 @ 25 fps), NTSC (640x480 @ 29.97 fps) + +Card number: 2 + +Pinnacle/Miro DC10(old) +~~~~~~~~~~~~~~~~~~~~~~~ + +* Zoran zr36057 PCI controller +* Zoran zr36050 MJPEG codec +* Zoran zr36016 Video Front End or Fuji md0211 Video Front End (clone?) +* Micronas vpx3220a TV decoder +* mse3000 TV encoder or Analog Devices adv7176 TV encoder + +Drivers to use: videodev, i2c-core, i2c-algo-bit, +videocodec, vpx3220, mse3000/adv7175, zr36050, zr36016, zr36067 + +Inputs/outputs: Composite, S-video and Internal + +Norms: PAL, SECAM (768x576 @ 25 fps), NTSC (640x480 @ 29.97 fps) + +Card number: 0 + +Pinnacle/Miro DC30 +~~~~~~~~~~~~~~~~~~ + +* Zoran zr36057 PCI controller +* Zoran zr36050 MJPEG codec +* Zoran zr36016 Video Front End +* Micronas vpx3225d/vpx3220a/vpx3216b TV decoder +* Analog Devices adv7176 TV encoder + +Drivers to use: videodev, i2c-core, i2c-algo-bit, +videocodec, vpx3220/vpx3224, adv7175, zr36050, zr36016, zr36067 + +Inputs/outputs: Composite, S-video and Internal + +Norms: PAL, SECAM (768x576 @ 25 fps), NTSC (640x480 @ 29.97 fps) + +Card number: 3 + +Pinnacle/Miro DC30+ +~~~~~~~~~~~~~~~~~~~ + +* Zoran zr36067 PCI controller +* Zoran zr36050 MJPEG codec +* Zoran zr36016 Video Front End +* Micronas vpx3225d/vpx3220a/vpx3216b TV decoder +* Analog Devices adv7176 TV encoder + +Drivers to use: videodev, i2c-core, i2c-algo-bit, +videocodec, vpx3220/vpx3224, adv7175, zr36050, zr36015, zr36067 + +Inputs/outputs: Composite, S-video and Internal + +Norms: PAL, SECAM (768x576 @ 25 fps), NTSC (640x480 @ 29.97 fps) + +Card number: 4 + +.. note:: + + #) No module for the mse3000 is available yet + #) No module for the vpx3224 is available yet + +1.1 What the TV decoder can do an what not +------------------------------------------ + +The best know TV standards are NTSC/PAL/SECAM. but for decoding a frame that +information is not enough. There are several formats of the TV standards. +And not every TV decoder is able to handle every format. Also the every +combination is supported by the driver. There are currently 11 different +tv broadcast formats all aver the world. + +The CCIR defines parameters needed for broadcasting the signal. +The CCIR has defined different standards: A,B,D,E,F,G,D,H,I,K,K1,L,M,N,... +The CCIR says not much about the colorsystem used !!! +And talking about a colorsystem says not to much about how it is broadcast. + +The CCIR standards A,E,F are not used any more. + +When you speak about NTSC, you usually mean the standard: CCIR - M using +the NTSC colorsystem which is used in the USA, Japan, Mexico, Canada +and a few others. + +When you talk about PAL, you usually mean: CCIR - B/G using the PAL +colorsystem which is used in many Countries. + +When you talk about SECAM, you mean: CCIR - L using the SECAM Colorsystem +which is used in France, and a few others. + +There the other version of SECAM, CCIR - D/K is used in Bulgaria, China, +Slovakai, Hungary, Korea (Rep.), Poland, Rumania and a others. + +The CCIR - H uses the PAL colorsystem (sometimes SECAM) and is used in +Egypt, Libya, Sri Lanka, Syrain Arab. Rep. + +The CCIR - I uses the PAL colorsystem, and is used in Great Britain, Hong Kong, +Ireland, Nigeria, South Africa. + +The CCIR - N uses the PAL colorsystem and PAL frame size but the NTSC framerate, +and is used in Argentinia, Uruguay, an a few others + +We do not talk about how the audio is broadcast ! + +A rather good sites about the TV standards are: +http://www.sony.jp/support/ +http://info.electronicwerkstatt.de/bereiche/fernsehtechnik/frequenzen_und_normen/Fernsehnormen/ +and http://www.cabl.com/restaurant/channel.html + +Other weird things around: NTSC 4.43 is a modificated NTSC, which is mainly +used in PAL VCR's that are able to play back NTSC. PAL 60 seems to be the same +as NTSC 4.43 . The Datasheets also talk about NTSC 44, It seems as if it would +be the same as NTSC 4.43. +NTSC Combs seems to be a decoder mode where the decoder uses a comb filter +to split coma and luma instead of a Delay line. + +But I did not defiantly find out what NTSC Comb is. + +Philips saa7111 TV decoder +~~~~~~~~~~~~~~~~~~~~~~~~~~ + +- was introduced in 1997, is used in the BUZ and +- can handle: PAL B/G/H/I, PAL N, PAL M, NTSC M, NTSC N, NTSC 4.43 and SECAM + +Philips saa7110a TV decoder +~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +- was introduced in 1995, is used in the Pinnacle/Miro DC10(new), DC10+ and +- can handle: PAL B/G, NTSC M and SECAM + +Philips saa7114 TV decoder +~~~~~~~~~~~~~~~~~~~~~~~~~~ + +- was introduced in 2000, is used in the LML33R10 and +- can handle: PAL B/G/D/H/I/N, PAL N, PAL M, NTSC M, NTSC 4.43 and SECAM + +Brooktree bt819 TV decoder +~~~~~~~~~~~~~~~~~~~~~~~~~~ + +- was introduced in 1996, and is used in the LML33 and +- can handle: PAL B/D/G/H/I, NTSC M + +Micronas vpx3220a TV decoder +~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +- was introduced in 1996, is used in the DC30 and DC30+ and +- can handle: PAL B/G/H/I, PAL N, PAL M, NTSC M, NTSC 44, PAL 60, SECAM,NTSC Comb + +Samsung ks0127 TV decoder +~~~~~~~~~~~~~~~~~~~~~~~~~ + +- is used in the AVS6EYES card and +- can handle: NTSC-M/N/44, PAL-M/N/B/G/H/I/D/K/L and SECAM + + +What the TV encoder can do an what not +-------------------------------------- + +The TV encoder is doing the "same" as the decoder, but in the other direction. +You feed them digital data and the generate a Composite or SVHS signal. +For information about the colorsystems and TV norm take a look in the +TV decoder section. + +Philips saa7185 TV Encoder +~~~~~~~~~~~~~~~~~~~~~~~~~~ + +- was introduced in 1996, is used in the BUZ +- can generate: PAL B/G, NTSC M + +Brooktree bt856 TV Encoder +~~~~~~~~~~~~~~~~~~~~~~~~~~ + +- was introduced in 1994, is used in the LML33 +- can generate: PAL B/D/G/H/I/N, PAL M, NTSC M, PAL-N (Argentina) + +Analog Devices adv7170 TV Encoder +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +- was introduced in 2000, is used in the LML300R10 +- can generate: PAL B/D/G/H/I/N, PAL M, NTSC M, PAL 60 + +Analog Devices adv7175 TV Encoder +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +- was introduced in 1996, is used in the DC10, DC10+, DC10 old, DC30, DC30+ +- can generate: PAL B/D/G/H/I/N, PAL M, NTSC M + +ITT mse3000 TV encoder +~~~~~~~~~~~~~~~~~~~~~~ + +- was introduced in 1991, is used in the DC10 old +- can generate: PAL , NTSC , SECAM + +Conexant bt866 TV encoder +~~~~~~~~~~~~~~~~~~~~~~~~~ + +- is used in AVS6EYES, and +- can generate: NTSC/PAL, PALM, PALN + +The adv717x, should be able to produce PAL N. But you find nothing PAL N +specific in the registers. Seem that you have to reuse a other standard +to generate PAL N, maybe it would work if you use the PAL M settings. + +How do I get this damn thing to work +------------------------------------ + +Load zr36067.o. If it can't autodetect your card, use the card=X insmod +option with X being the card number as given in the previous section. +To have more than one card, use card=X1[,X2[,X3,[X4[..]]]] + +To automate this, add the following to your /etc/modprobe.d/zoran.conf: + +options zr36067 card=X1[,X2[,X3[,X4[..]]]] +alias char-major-81-0 zr36067 + +One thing to keep in mind is that this doesn't load zr36067.o itself yet. It +just automates loading. If you start using xawtv, the device won't load on +some systems, since you're trying to load modules as a user, which is not +allowed ("permission denied"). A quick workaround is to add 'Load "v4l"' to +XF86Config-4 when you use X by default, or to run 'v4l-conf -c <device>' in +one of your startup scripts (normally rc.local) if you don't use X. Both +make sure that the modules are loaded on startup, under the root account. + +What mainboard should I use (or why doesn't my card work) +--------------------------------------------------------- + + +<insert lousy disclaimer here>. In short: good=SiS/Intel, bad=VIA. + +Experience tells us that people with a Buz, on average, have more problems +than users with a DC10+/LML33. Also, it tells us that people owning a VIA- +based mainboard (ktXXX, MVP3) have more problems than users with a mainboard +based on a different chipset. Here's some notes from Andrew Stevens: + +Here's my experience of using LML33 and Buz on various motherboards: + +- VIA MVP3 + - Forget it. Pointless. Doesn't work. +- Intel 430FX (Pentium 200) + - LML33 perfect, Buz tolerable (3 or 4 frames dropped per movie) +- Intel 440BX (early stepping) + - LML33 tolerable. Buz starting to get annoying (6-10 frames/hour) +- Intel 440BX (late stepping) + - Buz tolerable, LML3 almost perfect (occasional single frame drops) +- SiS735 + - LML33 perfect, Buz tolerable. +- VIA KT133(*) + - LML33 starting to get annoying, Buz poor enough that I have up. + +- Both 440BX boards were dual CPU versions. + +Bernhard Praschinger later added: + +- AMD 751 + - Buz perfect-tolerable +- AMD 760 + - Buz perfect-tolerable + +In general, people on the user mailinglist won't give you much of a chance +if you have a VIA-based motherboard. They may be cheap, but sometimes, you'd +rather want to spend some more money on better boards. In general, VIA +mainboard's IDE/PCI performance will also suck badly compared to others. +You'll noticed the DC10+/DC30+ aren't mentioned anywhere in the overview. +Basically, you can assume that if the Buz works, the LML33 will work too. If +the LML33 works, the DC10+/DC30+ will work too. They're most tolerant to +different mainboard chipsets from all of the supported cards. + +If you experience timeouts during capture, buy a better mainboard or lower +the quality/buffersize during capture (see 'Concerning buffer sizes, quality, +output size etc.'). If it hangs, there's little we can do as of now. Check +your IRQs and make sure the card has its own interrupts. + +Programming interface +--------------------- + +This driver conforms to video4linux2. Support for V4L1 and for the custom +zoran ioctls has been removed in kernel 2.6.38. + +For programming example, please, look at lavrec.c and lavplay.c code in +the MJPEG-tools (http://mjpeg.sf.net/). + +Additional notes for software developers: + + The driver returns maxwidth and maxheight parameters according to + the current TV standard (norm). Therefore, the software which + communicates with the driver and "asks" for these parameters should + first set the correct norm. Well, it seems logically correct: TV + standard is "more constant" for current country than geometry + settings of a variety of TV capture cards which may work in ITU or + square pixel format. + +Applications +------------ + +Applications known to work with this driver: + +TV viewing: + +* xawtv +* kwintv +* probably any TV application that supports video4linux or video4linux2. + +MJPEG capture/playback: + +* mjpegtools/lavtools (or Linux Video Studio) +* gstreamer +* mplayer + +General raw capture: + +* xawtv +* gstreamer +* probably any application that supports video4linux or video4linux2 + +Video editing: + +* Cinelerra +* MainActor +* mjpegtools (or Linux Video Studio) + + +Concerning buffer sizes, quality, output size etc. +-------------------------------------------------- + + +The zr36060 can do 1:2 JPEG compression. This is really the theoretical +maximum that the chipset can reach. The driver can, however, limit compression +to a maximum (size) of 1:4. The reason for this is that some cards (e.g. Buz) +can't handle 1:2 compression without stopping capture after only a few minutes. +With 1:4, it'll mostly work. If you have a Buz, use 'low_bitrate=1' to go into +1:4 max. compression mode. + +100% JPEG quality is thus 1:2 compression in practice. So for a full PAL frame +(size 720x576). The JPEG fields are stored in YUY2 format, so the size of the +fields are 720x288x16/2 bits/field (2 fields/frame) = 207360 bytes/field x 2 = +414720 bytes/frame (add some more bytes for headers and DHT (huffman)/DQT +(quantization) tables, and you'll get to something like 512kB per frame for +1:2 compression. For 1:4 compression, you'd have frames of half this size. + +Some additional explanation by Martin Samuelsson, which also explains the +importance of buffer sizes: +-- +> Hmm, I do not think it is really that way. With the current (downloaded +> at 18:00 Monday) driver I get that output sizes for 10 sec: +> -q 50 -b 128 : 24.283.332 Bytes +> -q 50 -b 256 : 48.442.368 +> -q 25 -b 128 : 24.655.992 +> -q 25 -b 256 : 25.859.820 + +I woke up, and can't go to sleep again. I'll kill some time explaining why +this doesn't look strange to me. + +Let's do some math using a width of 704 pixels. I'm not sure whether the Buz +actually use that number or not, but that's not too important right now. + +704x288 pixels, one field, is 202752 pixels. Divided by 64 pixels per block; +3168 blocks per field. Each pixel consist of two bytes; 128 bytes per block; +1024 bits per block. 100% in the new driver mean 1:2 compression; the maximum +output becomes 512 bits per block. Actually 510, but 512 is simpler to use +for calculations. + +Let's say that we specify d1q50. We thus want 256 bits per block; times 3168 +becomes 811008 bits; 101376 bytes per field. We're talking raw bits and bytes +here, so we don't need to do any fancy corrections for bits-per-pixel or such +things. 101376 bytes per field. + +d1 video contains two fields per frame. Those sum up to 202752 bytes per +frame, and one of those frames goes into each buffer. + +But wait a second! -b128 gives 128kB buffers! It's not possible to cram +202752 bytes of JPEG data into 128kB! + +This is what the driver notice and automatically compensate for in your +examples. Let's do some math using this information: + +128kB is 131072 bytes. In this buffer, we want to store two fields, which +leaves 65536 bytes for each field. Using 3168 blocks per field, we get +20.68686868... available bytes per block; 165 bits. We can't allow the +request for 256 bits per block when there's only 165 bits available! The -q50 +option is silently overridden, and the -b128 option takes precedence, leaving +us with the equivalence of -q32. + +This gives us a data rate of 165 bits per block, which, times 3168, sums up +to 65340 bytes per field, out of the allowed 65536. The current driver has +another level of rate limiting; it won't accept -q values that fill more than +6/8 of the specified buffers. (I'm not sure why. "Playing it safe" seem to be +a safe bet. Personally, I think I would have lowered requested-bits-per-block +by one, or something like that.) We can't use 165 bits per block, but have to +lower it again, to 6/8 of the available buffer space: We end up with 124 bits +per block, the equivalence of -q24. With 128kB buffers, you can't use greater +than -q24 at -d1. (And PAL, and 704 pixels width...) + +The third example is limited to -q24 through the same process. The second +example, using very similar calculations, is limited to -q48. The only +example that actually grab at the specified -q value is the last one, which +is clearly visible, looking at the file size. +-- + +Conclusion: the quality of the resulting movie depends on buffer size, quality, +whether or not you use 'low_bitrate=1' as insmod option for the zr36060.c +module to do 1:4 instead of 1:2 compression, etc. + +If you experience timeouts, lowering the quality/buffersize or using +'low_bitrate=1 as insmod option for zr36060.o might actually help, as is +proven by the Buz. + +It hangs/crashes/fails/whatevers! Help! +--------------------------------------- + +Make sure that the card has its own interrupts (see /proc/interrupts), check +the output of dmesg at high verbosity (load zr36067.o with debug=2, +load all other modules with debug=1). Check that your mainboard is favorable +(see question 2) and if not, test the card in another computer. Also see the +notes given in question 3 and try lowering quality/buffersize/capturesize +if recording fails after a period of time. + +If all this doesn't help, give a clear description of the problem including +detailed hardware information (memory+brand, mainboard+chipset+brand, which +MJPEG card, processor, other PCI cards that might be of interest), give the +system PnP information (/proc/interrupts, /proc/dma, /proc/devices), and give +the kernel version, driver version, glibc version, gcc version and any other +information that might possibly be of interest. Also provide the dmesg output +at high verbosity. See 'Contacting' on how to contact the developers. + +Maintainers/Contacting +---------------------- + +Previous maintainers/developers of this driver are +- Laurent Pinchart <laurent.pinchart@skynet.be> +- Ronald Bultje rbultje@ronald.bitfreak.net +- Serguei Miridonov <mirsev@cicese.mx> +- Wolfgang Scherr <scherr@net4you.net> +- Dave Perks <dperks@ibm.net> +- Rainer Johanni <Rainer@Johanni.de> + +Driver's License +---------------- + + This driver is distributed under the terms of the General Public License. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + +See http://www.gnu.org/ for more information. diff --git a/Documentation/driver-api/media/drivers/vidtv.rst b/Documentation/driver-api/media/drivers/vidtv.rst new file mode 100644 index 000000000000..65115448c52d --- /dev/null +++ b/Documentation/driver-api/media/drivers/vidtv.rst @@ -0,0 +1,425 @@ +.. SPDX-License-Identifier: GPL-2.0 + +================================ +vidtv: Virtual Digital TV driver +================================ + +Author: Daniel W. S. Almeida <dwlsalmeida@gmail.com>, June 2020. + +Background +---------- + +Vidtv is a virtual DVB driver that aims to serve as a reference for driver +writers by serving as a template. It also validates the existing media DVB +APIs, thus helping userspace application writers. + +Currently, it consists of: + +- A fake tuner driver, which will report a bad signal quality if the chosen + frequency is too far away from a table of valid frequencies for a + particular delivery system. + +- A fake demod driver, which will constantly poll the fake signal quality + returned by the tuner, simulating a device that can lose/reacquire a lock + on the signal depending on the CNR levels. + +- A fake bridge driver, which is the module responsible for modprobing the + fake tuner and demod modules and implementing the demux logic. This module + takes parameters at initialization that will dictate how the simulation + behaves. + +- Code reponsible for encoding a valid MPEG Transport Stream, which is then + passed to the bridge driver. This fake stream contains some hardcoded content. + For now, we have a single, audio-only channel containing a single MPEG + Elementary Stream, which in turn contains a SMPTE 302m encoded sine-wave. + Note that this particular encoder was chosen because it is the easiest + way to encode PCM audio data in a MPEG Transport Stream. + +Building vidtv +-------------- +vidtv is a test driver and thus is **not** enabled by default when +compiling the kernel. + +In order to enable compilation of vidtv: + +- Enable **DVB_TEST_DRIVERS**, then +- Enable **DVB_VIDTV** + +When compiled as a module, expect the following .ko files: + +- dvb_vidtv_tuner.ko + +- dvb_vidtv_demod.ko + +- dvb_vidtv_bridge.ko + +Running vidtv +------------- +When compiled as a module, run:: + + modprobe vidtv + +That's it! The bridge driver will initialize the tuner and demod drivers as +part of its own initialization. + +By default, it will accept the following frequencies: + + - 474 MHz for DVB-T/T2/C; + - 11,362 GHz for DVB-S/S2. + +For satellite systems, the driver simulates an universal extended +LNBf, with frequencies at Ku-Band, ranging from 10.7 GHz to 12.75 GHz. + +You can optionally define some command-line arguments to vidtv. + +Command-line arguments to vidtv +------------------------------- +Below is a list of all arguments that can be supplied to vidtv: + +drop_tslock_prob_on_low_snr + Probability of losing the TS lock if the signal quality is bad. + This probability be used by the fake demodulator driver to + eventually return a status of 0 when the signal quality is not + good. + +recover_tslock_prob_on_good_snr: + Probability recovering the TS lock when the signal improves. This + probability be used by the fake demodulator driver to eventually + return a status of 0x1f when/if the signal quality improves. + +mock_power_up_delay_msec + Simulate a power up delay. Default: 0. + +mock_tune_delay_msec + Simulate a tune delay. Default 0. + +vidtv_valid_dvb_t_freqs + Valid DVB-T frequencies to simulate, in Hz. + +vidtv_valid_dvb_c_freqs + Valid DVB-C frequencies to simulate, in Hz. + +vidtv_valid_dvb_s_freqs + Valid DVB-S/S2 frequencies to simulate at Ku-Band, in kHz. + +max_frequency_shift_hz, + Maximum shift in HZ allowed when tuning in a channel. + +si_period_msec + How often to send SI packets. Default: 40ms. + +pcr_period_msec + How often to send PCR packets. Default: 40ms. + +mux_rate_kbytes_sec + Attempt to maintain this bit rate by inserting TS null packets, if + necessary. Default: 4096. + +pcr_pid, + PCR PID for all channels. Default: 0x200. + +mux_buf_sz_pkts, + Size for the mux buffer in multiples of 188 bytes. + +vidtv internal structure +------------------------ +The kernel modules are split in the following way: + +vidtv_tuner.[ch] + Implements a fake tuner DVB driver. + +vidtv_demod.[ch] + Implements a fake demodulator DVB driver. + +vidtv_bridge.[ch] + Implements a bridge driver. + +The MPEG related code is split in the following way: + +vidtv_ts.[ch] + Code to work with MPEG TS packets, such as TS headers, adaptation + fields, PCR packets and NULL packets. + +vidtv_psi.[ch] + This is the PSI generator. PSI packets contain general information + about a MPEG Transport Stream. A PSI generator is needed so + userspace apps can retrieve information about the Transport Stream + and eventually tune into a (dummy) channel. + + Because the generator is implemented in a separate file, it can be + reused elsewhere in the media subsystem. + + Currently vidtv supports working with 3 PSI tables: PAT, PMT and + SDT. + + The specification for PAT and PMT can be found in *ISO 13818-1: + Systems*, while the specification for the SDT can be found in *ETSI + EN 300 468: Specification for Service Information (SI) in DVB + systems*. + + It isn't strictly necessary, but using a real TS file helps when + debugging PSI tables. Vidtv currently tries to replicate the PSI + structure found in this file: `TS1Globo.ts + <https://tsduck.io/streams/brazil-isdb-tb/TS1globo.ts>`_. + + A good way to visualize the structure of streams is by using + `DVBInspector <https://sourceforge.net/projects/dvbinspector/>`_. + +vidtv_pes.[ch] + Implements the PES logic to convert encoder data into MPEG TS + packets. These can then be fed into a TS multiplexer and eventually + into userspace. + +vidtv_encoder.h + An interface for vidtv encoders. New encoders can be added to this + driver by implementing the calls in this file. + +vidtv_s302m.[ch] + Implements a S302M encoder to make it possible to insert PCM audio + data in the generated MPEG Transport Stream. The relevant + specification is available online as *SMPTE 302M-2007: Television - + Mapping of AES3 Data into MPEG-2 Transport Stream*. + + + The resulting MPEG Elementary Stream is conveyed in a private + stream with a S302M registration descriptor attached. + + This shall enable passing an audio signal into userspace so it can + be decoded and played by media software. The corresponding decoder + in ffmpeg is located in 'libavcodec/s302m.c' and is experimental. + +vidtv_channel.[ch] + Implements a 'channel' abstraction. + + When vidtv boots, it will create some hardcoded channels: + + #. Their services will be concatenated to populate the SDT. + + #. Their programs will be concatenated to populate the PAT + + #. For each program in the PAT, a PMT section will be created + + #. The PMT section for a channel will be assigned its streams. + + #. Every stream will have its corresponding encoder polled in a + loop to produce TS packets. + These packets may be interleaved by the muxer and then delivered + to the bridge. + +vidtv_mux.[ch] + Implements a MPEG TS mux, loosely based on the ffmpeg + implementation in "libavcodec/mpegtsenc.c" + + The muxer runs a loop which is responsible for: + + #. Keeping track of the amount of time elapsed since the last + iteration. + + #. Polling encoders in order to fetch 'elapsed_time' worth of data. + + #. Inserting PSI and/or PCR packets, if needed. + + #. Padding the resulting stream with NULL packets if + necessary in order to maintain the chosen bit rate. + + #. Delivering the resulting TS packets to the bridge + driver so it can pass them to the demux. + +Testing vidtv with v4l-utils +---------------------------- + +Using the tools in v4l-utils is a great way to test and inspect the output of +vidtv. It is hosted here: `v4l-utils Documentation +<https://linuxtv.org/wiki/index.php/V4l-utils>`_. + +From its webpage:: + + The v4l-utils are a series of packages for handling media devices. + + It is hosted at http://git.linuxtv.org/v4l-utils.git, and packaged + on most distributions. + + It provides a series of libraries and utilities to be used to + control several aspect of the media boards. + + +Start by installing v4l-utils and then modprobing vidtv:: + + modprobe dvb_vidtv_bridge + +If the driver is OK, it should load and its probing code will run. This will +pull in the tuner and demod drivers. + +Using dvb-fe-tool +~~~~~~~~~~~~~~~~~ + +The first step to check whether the demod loaded successfully is to run:: + + $ dvb-fe-tool + +This should return what is currently set up at the demod struct, i.e.:: + + static const struct dvb_frontend_ops vidtv_demod_ops = { + .delsys = { + SYS_DVBT, + SYS_DVBT2, + SYS_DVBC_ANNEX_A, + SYS_DVBS, + SYS_DVBS2, + }, + + .info = { + .name = "Dummy demod for DVB-T/T2/C/S/S2", + .frequency_min_hz = 51 * MHz, + .frequency_max_hz = 2150 * MHz, + .frequency_stepsize_hz = 62500, + .frequency_tolerance_hz = 29500 * kHz, + .symbol_rate_min = 1000000, + .symbol_rate_max = 45000000, + + .caps = FE_CAN_FEC_1_2 | + FE_CAN_FEC_2_3 | + FE_CAN_FEC_3_4 | + FE_CAN_FEC_4_5 | + FE_CAN_FEC_5_6 | + FE_CAN_FEC_6_7 | + FE_CAN_FEC_7_8 | + FE_CAN_FEC_8_9 | + FE_CAN_QAM_16 | + FE_CAN_QAM_64 | + FE_CAN_QAM_32 | + FE_CAN_QAM_128 | + FE_CAN_QAM_256 | + FE_CAN_QAM_AUTO | + FE_CAN_QPSK | + FE_CAN_FEC_AUTO | + FE_CAN_INVERSION_AUTO | + FE_CAN_TRANSMISSION_MODE_AUTO | + FE_CAN_GUARD_INTERVAL_AUTO | + FE_CAN_HIERARCHY_AUTO, + } + + .... + +For more information on dvb-fe-tools check its online documentation here: +`dvb-fe-tool Documentation +<https://www.linuxtv.org/wiki/index.php/Dvb-fe-tool>`_. + +Using dvb-scan +~~~~~~~~~~~~~~ + +In order to tune into a channel and read the PSI tables, we can use dvb-scan. + +For this, one should provide a configuration file known as a 'scan file', +here's an example:: + + [Channel] + FREQUENCY = 330000000 + MODULATION = QAM/AUTO + SYMBOL_RATE = 6940000 + INNER_FEC = AUTO + DELIVERY_SYSTEM = DVBC/ANNEX_A + +.. note:: + The parameters depend on the video standard you're testing. + +.. note:: + Vidtv is a fake driver and does not validate much of the information + in the scan file. Just specifying 'FREQUENCY' and 'DELIVERY_SYSTEM' + should be enough for DVB-T/DVB-T2. For DVB-S/DVB-C however, you + should also provide 'SYMBOL_RATE'. + +You can browse scan tables online here: `dvb-scan-tables +<https://git.linuxtv.org/dtv-scan-tables.git>`_. + +Assuming this channel is named 'channel.conf', you can then run:: + + $ dvbv5-scan channel.conf + +For more information on dvb-scan, check its documentation online here: +`dvb-scan Documentation <https://www.linuxtv.org/wiki/index.php/Dvbscan>`_. + +Using dvb-zap +~~~~~~~~~~~~~ + +dvbv5-zap is a command line tool that can be used to record MPEG-TS to disk. The +typical use is to tune into a channel and put it into record mode. The example +below - which is taken from the documentation - illustrates that:: + + $ dvbv5-zap -c dvb_channel.conf "trilhas sonoras" -r + using demux '/dev/dvb/adapter0/demux0' + reading channels from file 'dvb_channel.conf' + service has pid type 05: 204 + tuning to 573000000 Hz + audio pid 104 + dvb_set_pesfilter 104 + Lock (0x1f) Quality= Good Signal= 100.00% C/N= -13.80dB UCB= 70 postBER= 3.14x10^-3 PER= 0 + DVR interface '/dev/dvb/adapter0/dvr0' can now be opened + +The channel can be watched by playing the contents of the DVR interface, with +some player that recognizes the MPEG-TS format, such as *mplayer* or *vlc*. + +By playing the contents of the stream one can visually inspect the workings of +vidtv, e.g.:: + + $ mplayer /dev/dvb/adapter0/dvr0 + +For more information on dvb-zap check its online documentation here: +`dvb-zap Documentation +<https://www.linuxtv.org/wiki/index.php/Dvbv5-zap>`_. +See also: `zap <https://www.linuxtv.org/wiki/index.php/Zap>`_. + + +What can still be improved in vidtv +----------------------------------- + +Add *debugfs* integration +~~~~~~~~~~~~~~~~~~~~~~~~~ + +Although frontend drivers provide DVBv5 statistics via the .read_status +call, a nice addition would be to make additional statistics available to +userspace via debugfs, which is a simple-to-use, RAM-based filesystem +specifically designed for debug purposes. + +The logic for this would be implemented on a separate file so as not to +pollute the frontend driver. These statistics are driver-specific and can +be useful during tests. + +The Siano driver is one example of a driver using +debugfs to convey driver-specific statistics to userspace and it can be +used as a reference. + +This should be further enabled and disabled via a Kconfig +option for convenience. + +Add a way to test video +~~~~~~~~~~~~~~~~~~~~~~~ + +Currently, vidtv can only encode PCM audio. It would be great to implement +a barebones version of MPEG-2 video encoding so we can also test video. The +first place to look into is *ISO 13818-2: Information technology — Generic +coding of moving pictures and associated audio information — Part 2: Video*, +which covers the encoding of compressed video in MPEG Transport Streams. + +This might optionally use the Video4Linux2 Test Pattern Generator, v4l2-tpg, +which resides at:: + + drivers/media/common/v4l2-tpg/ + + +Add white noise simulation +~~~~~~~~~~~~~~~~~~~~~~~~~~ + +The vidtv tuner already has code to identify whether the chosen frequency +is too far away from a table of valid frequencies. For now, this means that +the demodulator can eventually lose the lock on the signal, since the tuner will +report a bad signal quality. + +A nice addition is to simulate some noise when the signal quality is bad by: + +- Randomly dropping some TS packets. This will trigger a continuity error if the + continuity counter is updated but the packet is not passed on to the demux. + +- Updating the error statistics accordingly (e.g. BER, etc). + +- Simulating some noise in the encoded data. diff --git a/Documentation/driver-api/media/index.rst b/Documentation/driver-api/media/index.rst index 328350924853..c140692454b1 100644 --- a/Documentation/driver-api/media/index.rst +++ b/Documentation/driver-api/media/index.rst @@ -34,6 +34,7 @@ Please see: mc-core cec-core csi2 + camera-sensor drivers/index diff --git a/Documentation/driver-api/media/v4l2-subdev.rst b/Documentation/driver-api/media/v4l2-subdev.rst index bc7e1fc40a9d..6248ea99e979 100644 --- a/Documentation/driver-api/media/v4l2-subdev.rst +++ b/Documentation/driver-api/media/v4l2-subdev.rst @@ -34,7 +34,7 @@ provides host private data for that purpose that can be accessed with From the bridge driver perspective, you load the sub-device module and somehow obtain the :c:type:`v4l2_subdev` pointer. For i2c devices this is easy: you call ``i2c_get_clientdata()``. For other buses something similar needs to be done. -Helper functions exists for sub-devices on an I2C bus that do most of this +Helper functions exist for sub-devices on an I2C bus that do most of this tricky work for you. Each :c:type:`v4l2_subdev` contains function pointers that sub-device drivers @@ -138,6 +138,9 @@ ensures that width, height and the media bus pixel code are equal on both source and sink of the link. Subdev drivers are also free to use this function to perform the checks mentioned above in addition to their own checks. +Subdev registration +~~~~~~~~~~~~~~~~~~~ + There are currently two ways to register subdevices with the V4L2 core. The first (traditional) possibility is to have subdevices registered by bridge drivers. This can be done when the bridge driver has the complete information @@ -157,7 +160,7 @@ below. Using one or the other registration method only affects the probing process, the run-time bridge-subdevice interaction is in both cases the same. -In the synchronous case a device (bridge) driver needs to register the +In the **synchronous** case a device (bridge) driver needs to register the :c:type:`v4l2_subdev` with the v4l2_device: :c:func:`v4l2_device_register_subdev <v4l2_device_register_subdev>` @@ -179,7 +182,51 @@ You can unregister a sub-device using: Afterwards the subdev module can be unloaded and :c:type:`sd <v4l2_subdev>`->dev == ``NULL``. -You can call an ops function either directly: +In the **asynchronous** case subdevice probing can be invoked independently of +the bridge driver availability. The subdevice driver then has to verify whether +all the requirements for a successful probing are satisfied. This can include a +check for a master clock availability. If any of the conditions aren't satisfied +the driver might decide to return ``-EPROBE_DEFER`` to request further reprobing +attempts. Once all conditions are met the subdevice shall be registered using +the :c:func:`v4l2_async_register_subdev` function. Unregistration is +performed using the :c:func:`v4l2_async_unregister_subdev` call. Subdevices +registered this way are stored in a global list of subdevices, ready to be +picked up by bridge drivers. + +Bridge drivers in turn have to register a notifier object. This is +performed using the :c:func:`v4l2_async_notifier_register` call. To +unregister the notifier the driver has to call +:c:func:`v4l2_async_notifier_unregister`. The former of the two functions +takes two arguments: a pointer to struct :c:type:`v4l2_device` and a +pointer to struct :c:type:`v4l2_async_notifier`. + +Before registering the notifier, bridge drivers must do two things: +first, the notifier must be initialized using the +:c:func:`v4l2_async_notifier_init`. Second, bridge drivers can then +begin to form a list of subdevice descriptors that the bridge device +needs for its operation. Subdevice descriptors are added to the notifier +using the :c:func:`v4l2_async_notifier_add_subdev` call. This function +takes two arguments: a pointer to struct :c:type:`v4l2_async_notifier`, +and a pointer to the subdevice descripter, which is of type struct +:c:type:`v4l2_async_subdev`. + +The V4L2 core will then use these descriptors to match asynchronously +registered subdevices to them. If a match is detected the ``.bound()`` +notifier callback is called. After all subdevices have been located the +.complete() callback is called. When a subdevice is removed from the +system the .unbind() method is called. All three callbacks are optional. + +Calling subdev operations +~~~~~~~~~~~~~~~~~~~~~~~~~ + +The advantage of using :c:type:`v4l2_subdev` is that it is a generic struct and +does not contain any knowledge about the underlying hardware. So a driver might +contain several subdevs that use an I2C bus, but also a subdev that is +controlled through GPIO pins. This distinction is only relevant when setting +up the device, but once the subdev is registered it is completely transparent. + +Once te subdev has been registered you can call an ops function either +directly: .. code-block:: c @@ -191,7 +238,7 @@ but it is better and easier to use this macro: err = v4l2_subdev_call(sd, core, g_std, &norm); -The macro will to the right ``NULL`` pointer checks and returns ``-ENODEV`` +The macro will do the right ``NULL`` pointer checks and returns ``-ENODEV`` if :c:type:`sd <v4l2_subdev>` is ``NULL``, ``-ENOIOCTLCMD`` if either :c:type:`sd <v4l2_subdev>`->core or :c:type:`sd <v4l2_subdev>`->core->g_std is ``NULL``, or the actual result of the :c:type:`sd <v4l2_subdev>`->ops->core->g_std ops. @@ -232,46 +279,6 @@ it can call ``v4l2_subdev_notify(sd, notification, arg)``. This macro checks whether there is a ``notify()`` callback defined and returns ``-ENODEV`` if not. Otherwise the result of the ``notify()`` call is returned. -The advantage of using :c:type:`v4l2_subdev` is that it is a generic struct and -does not contain any knowledge about the underlying hardware. So a driver might -contain several subdevs that use an I2C bus, but also a subdev that is -controlled through GPIO pins. This distinction is only relevant when setting -up the device, but once the subdev is registered it is completely transparent. - -In the asynchronous case subdevice probing can be invoked independently of the -bridge driver availability. The subdevice driver then has to verify whether all -the requirements for a successful probing are satisfied. This can include a -check for a master clock availability. If any of the conditions aren't satisfied -the driver might decide to return ``-EPROBE_DEFER`` to request further reprobing -attempts. Once all conditions are met the subdevice shall be registered using -the :c:func:`v4l2_async_register_subdev` function. Unregistration is -performed using the :c:func:`v4l2_async_unregister_subdev` call. Subdevices -registered this way are stored in a global list of subdevices, ready to be -picked up by bridge drivers. - -Bridge drivers in turn have to register a notifier object. This is -performed using the :c:func:`v4l2_async_notifier_register` call. To -unregister the notifier the driver has to call -:c:func:`v4l2_async_notifier_unregister`. The former of the two functions -takes two arguments: a pointer to struct :c:type:`v4l2_device` and a -pointer to struct :c:type:`v4l2_async_notifier`. - -Before registering the notifier, bridge drivers must do two things: -first, the notifier must be initialized using the -:c:func:`v4l2_async_notifier_init`. Second, bridge drivers can then -begin to form a list of subdevice descriptors that the bridge device -needs for its operation. Subdevice descriptors are added to the notifier -using the :c:func:`v4l2_async_notifier_add_subdev` call. This function -takes two arguments: a pointer to struct :c:type:`v4l2_async_notifier`, -and a pointer to the subdevice descripter, which is of type struct -:c:type:`v4l2_async_subdev`. - -The V4L2 core will then use these descriptors to match asynchronously -registered subdevices to them. If a match is detected the ``.bound()`` -notifier callback is called. After all subdevices have been located the -.complete() callback is called. When a subdevice is removed from the -system the .unbind() method is called. All three callbacks are optional. - V4L2 sub-device userspace API ----------------------------- @@ -488,5 +495,3 @@ V4L2 sub-device functions and data structures --------------------------------------------- .. kernel-doc:: include/media/v4l2-subdev.h - -.. kernel-doc:: include/media/v4l2-async.h |