diff options
Diffstat (limited to 'Documentation/driver-api')
| -rw-r--r-- | Documentation/driver-api/80211/mac80211.rst | 2 | ||||
| -rw-r--r-- | Documentation/driver-api/dma-buf.rst | 32 | ||||
| -rw-r--r-- | Documentation/driver-api/dpll.rst | 551 | ||||
| -rw-r--r-- | Documentation/driver-api/driver-model/devres.rst | 14 | ||||
| -rw-r--r-- | Documentation/driver-api/gpio/consumer.rst | 4 | ||||
| -rw-r--r-- | Documentation/driver-api/i3c/protocol.rst | 4 | ||||
| -rw-r--r-- | Documentation/driver-api/index.rst | 1 | ||||
| -rw-r--r-- | Documentation/driver-api/pps.rst | 16 | ||||
| -rw-r--r-- | Documentation/driver-api/pwm.rst | 6 | ||||
| -rw-r--r-- | Documentation/driver-api/thermal/intel_dptf.rst | 64 | ||||
| -rw-r--r-- | Documentation/driver-api/tty/index.rst | 1 | ||||
| -rw-r--r-- | Documentation/driver-api/tty/tty_ioctl.rst | 10 | ||||
| -rw-r--r-- | Documentation/driver-api/usb/dma.rst | 48 |
13 files changed, 693 insertions, 60 deletions
diff --git a/Documentation/driver-api/80211/mac80211.rst b/Documentation/driver-api/80211/mac80211.rst index 67d2e58b45e4..e38a220401f5 100644 --- a/Documentation/driver-api/80211/mac80211.rst +++ b/Documentation/driver-api/80211/mac80211.rst @@ -120,7 +120,7 @@ functions/definitions ieee80211_rx ieee80211_rx_ni ieee80211_rx_irqsafe - ieee80211_tx_status + ieee80211_tx_status_skb ieee80211_tx_status_ni ieee80211_tx_status_irqsafe ieee80211_rts_get diff --git a/Documentation/driver-api/dma-buf.rst b/Documentation/driver-api/dma-buf.rst index f92a32d095d9..0c153d79ccc4 100644 --- a/Documentation/driver-api/dma-buf.rst +++ b/Documentation/driver-api/dma-buf.rst @@ -5,14 +5,30 @@ The dma-buf subsystem provides the framework for sharing buffers for hardware (DMA) access across multiple device drivers and subsystems, and for synchronizing asynchronous hardware access. -This is used, for example, by drm "prime" multi-GPU support, but is of -course not limited to GPU use cases. - -The three main components of this are: (1) dma-buf, representing a -sg_table and exposed to userspace as a file descriptor to allow passing -between devices, (2) fence, which provides a mechanism to signal when -one device has finished access, and (3) reservation, which manages the -shared or exclusive fence(s) associated with the buffer. +As an example, it is used extensively by the DRM subsystem to exchange +buffers between processes, contexts, library APIs within the same +process, and also to exchange buffers with other subsystems such as +V4L2. + +This document describes the way in which kernel subsystems can use and +interact with the three main primitives offered by dma-buf: + + - dma-buf, representing a sg_table and exposed to userspace as a file + descriptor to allow passing between processes, subsystems, devices, + etc; + - dma-fence, providing a mechanism to signal when an asynchronous + hardware operation has completed; and + - dma-resv, which manages a set of dma-fences for a particular dma-buf + allowing implicit (kernel-ordered) synchronization of work to + preserve the illusion of coherent access + + +Userspace API principles and use +-------------------------------- + +For more details on how to design your subsystem's API for dma-buf use, please +see Documentation/userspace-api/dma-buf-alloc-exchange.rst. + Shared DMA Buffers ------------------ diff --git a/Documentation/driver-api/dpll.rst b/Documentation/driver-api/dpll.rst new file mode 100644 index 000000000000..e3d593841aa7 --- /dev/null +++ b/Documentation/driver-api/dpll.rst @@ -0,0 +1,551 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=============================== +The Linux kernel dpll subsystem +=============================== + +DPLL +==== + +PLL - Phase Locked Loop is an electronic circuit which syntonizes clock +signal of a device with an external clock signal. Effectively enabling +device to run on the same clock signal beat as provided on a PLL input. + +DPLL - Digital Phase Locked Loop is an integrated circuit which in +addition to plain PLL behavior incorporates a digital phase detector +and may have digital divider in the loop. As a result, the frequency on +DPLL's input and output may be configurable. + +Subsystem +========= + +The main purpose of dpll subsystem is to provide general interface +to configure devices that use any kind of Digital PLL and could use +different sources of input signal to synchronize to, as well as +different types of outputs. +The main interface is NETLINK_GENERIC based protocol with an event +monitoring multicast group defined. + +Device object +============= + +Single dpll device object means single Digital PLL circuit and bunch of +connected pins. +It reports the supported modes of operation and current status to the +user in response to the `do` request of netlink command +``DPLL_CMD_DEVICE_GET`` and list of dplls registered in the subsystem +with `dump` netlink request of the same command. +Changing the configuration of dpll device is done with `do` request of +netlink ``DPLL_CMD_DEVICE_SET`` command. +A device handle is ``DPLL_A_ID``, it shall be provided to get or set +configuration of particular device in the system. It can be obtained +with a ``DPLL_CMD_DEVICE_GET`` `dump` request or +a ``DPLL_CMD_DEVICE_ID_GET`` `do` request, where the one must provide +attributes that result in single device match. + +Pin object +========== + +A pin is amorphic object which represents either input or output, it +could be internal component of the device, as well as externally +connected. +The number of pins per dpll vary, but usually multiple pins shall be +provided for a single dpll device. +Pin's properties, capabilities and status is provided to the user in +response to `do` request of netlink ``DPLL_CMD_PIN_GET`` command. +It is also possible to list all the pins that were registered in the +system with `dump` request of ``DPLL_CMD_PIN_GET`` command. +Configuration of a pin can be changed by `do` request of netlink +``DPLL_CMD_PIN_SET`` command. +Pin handle is a ``DPLL_A_PIN_ID``, it shall be provided to get or set +configuration of particular pin in the system. It can be obtained with +``DPLL_CMD_PIN_GET`` `dump` request or ``DPLL_CMD_PIN_ID_GET`` `do` +request, where user provides attributes that result in single pin match. + +Pin selection +============= + +In general, selected pin (the one which signal is driving the dpll +device) can be obtained from ``DPLL_A_PIN_STATE`` attribute, and only +one pin shall be in ``DPLL_PIN_STATE_CONNECTED`` state for any dpll +device. + +Pin selection can be done either manually or automatically, depending +on hardware capabilities and active dpll device work mode +(``DPLL_A_MODE`` attribute). The consequence is that there are +differences for each mode in terms of available pin states, as well as +for the states the user can request for a dpll device. + +In manual mode (``DPLL_MODE_MANUAL``) the user can request or receive +one of following pin states: + +- ``DPLL_PIN_STATE_CONNECTED`` - the pin is used to drive dpll device +- ``DPLL_PIN_STATE_DISCONNECTED`` - the pin is not used to drive dpll + device + +In automatic mode (``DPLL_MODE_AUTOMATIC``) the user can request or +receive one of following pin states: + +- ``DPLL_PIN_STATE_SELECTABLE`` - the pin shall be considered as valid + input for automatic selection algorithm +- ``DPLL_PIN_STATE_DISCONNECTED`` - the pin shall be not considered as + a valid input for automatic selection algorithm + +In automatic mode (``DPLL_MODE_AUTOMATIC``) the user can only receive +pin state ``DPLL_PIN_STATE_CONNECTED`` once automatic selection +algorithm locks a dpll device with one of the inputs. + +Shared pins +=========== + +A single pin object can be attached to multiple dpll devices. +Then there are two groups of configuration knobs: + +1) Set on a pin - the configuration affects all dpll devices pin is + registered to (i.e., ``DPLL_A_PIN_FREQUENCY``), +2) Set on a pin-dpll tuple - the configuration affects only selected + dpll device (i.e., ``DPLL_A_PIN_PRIO``, ``DPLL_A_PIN_STATE``, + ``DPLL_A_PIN_DIRECTION``). + +MUX-type pins +============= + +A pin can be MUX-type, it aggregates child pins and serves as a pin +multiplexer. One or more pins are registered with MUX-type instead of +being directly registered to a dpll device. +Pins registered with a MUX-type pin provide user with additional nested +attribute ``DPLL_A_PIN_PARENT_PIN`` for each parent they were registered +with. +If a pin was registered with multiple parent pins, they behave like a +multiple output multiplexer. In this case output of a +``DPLL_CMD_PIN_GET`` would contain multiple pin-parent nested +attributes with current state related to each parent, like:: + + 'pin': [{{ + 'clock-id': 282574471561216, + 'module-name': 'ice', + 'capabilities': 4, + 'id': 13, + 'parent-pin': [ + {'parent-id': 2, 'state': 'connected'}, + {'parent-id': 3, 'state': 'disconnected'} + ], + 'type': 'synce-eth-port' + }}] + +Only one child pin can provide its signal to the parent MUX-type pin at +a time, the selection is done by requesting change of a child pin state +on desired parent, with the use of ``DPLL_A_PIN_PARENT`` nested +attribute. Example of netlink `set state on parent pin` message format: + + ========================== ============================================= + ``DPLL_A_PIN_ID`` child pin id + ``DPLL_A_PIN_PARENT_PIN`` nested attribute for requesting configuration + related to parent pin + ``DPLL_A_PIN_PARENT_ID`` parent pin id + ``DPLL_A_PIN_STATE`` requested pin state on parent + ========================== ============================================= + +Pin priority +============ + +Some devices might offer a capability of automatic pin selection mode +(enum value ``DPLL_MODE_AUTOMATIC`` of ``DPLL_A_MODE`` attribute). +Usually, automatic selection is performed on the hardware level, which +means only pins directly connected to the dpll can be used for automatic +input pin selection. +In automatic selection mode, the user cannot manually select a input +pin for the device, instead the user shall provide all directly +connected pins with a priority ``DPLL_A_PIN_PRIO``, the device would +pick a highest priority valid signal and use it to control the DPLL +device. Example of netlink `set priority on parent pin` message format: + + ============================ ============================================= + ``DPLL_A_PIN_ID`` configured pin id + ``DPLL_A_PIN_PARENT_DEVICE`` nested attribute for requesting configuration + related to parent dpll device + ``DPLL_A_PIN_PARENT_ID`` parent dpll device id + ``DPLL_A_PIN_PRIO`` requested pin prio on parent dpll + ============================ ============================================= + +Child pin of MUX-type pin is not capable of automatic input pin selection, +in order to configure active input of a MUX-type pin, the user needs to +request desired pin state of the child pin on the parent pin, +as described in the ``MUX-type pins`` chapter. + +Phase offset measurement and adjustment +======================================== + +Device may provide ability to measure a phase difference between signals +on a pin and its parent dpll device. If pin-dpll phase offset measurement +is supported, it shall be provided with ``DPLL_A_PIN_PHASE_OFFSET`` +attribute for each parent dpll device. + +Device may also provide ability to adjust a signal phase on a pin. +If pin phase adjustment is supported, minimal and maximal values that pin +handle shall be provide to the user on ``DPLL_CMD_PIN_GET`` respond +with ``DPLL_A_PIN_PHASE_ADJUST_MIN`` and ``DPLL_A_PIN_PHASE_ADJUST_MAX`` +attributes. Configured phase adjust value is provided with +``DPLL_A_PIN_PHASE_ADJUST`` attribute of a pin, and value change can be +requested with the same attribute with ``DPLL_CMD_PIN_SET`` command. + + =============================== ====================================== + ``DPLL_A_PIN_ID`` configured pin id + ``DPLL_A_PIN_PHASE_ADJUST_MIN`` attr minimum value of phase adjustment + ``DPLL_A_PIN_PHASE_ADJUST_MAX`` attr maximum value of phase adjustment + ``DPLL_A_PIN_PHASE_ADJUST`` attr configured value of phase + adjustment on parent dpll device + ``DPLL_A_PIN_PARENT_DEVICE`` nested attribute for requesting + configuration on given parent dpll + device + ``DPLL_A_PIN_PARENT_ID`` parent dpll device id + ``DPLL_A_PIN_PHASE_OFFSET`` attr measured phase difference + between a pin and parent dpll device + =============================== ====================================== + +All phase related values are provided in pico seconds, which represents +time difference between signals phase. The negative value means that +phase of signal on pin is earlier in time than dpll's signal. Positive +value means that phase of signal on pin is later in time than signal of +a dpll. + +Phase adjust (also min and max) values are integers, but measured phase +offset values are fractional with 3-digit decimal places and shell be +divided with ``DPLL_PIN_PHASE_OFFSET_DIVIDER`` to get integer part and +modulo divided to get fractional part. + +Configuration commands group +============================ + +Configuration commands are used to get information about registered +dpll devices (and pins), as well as set configuration of device or pins. +As dpll devices must be abstracted and reflect real hardware, +there is no way to add new dpll device via netlink from user space and +each device should be registered by its driver. + +All netlink commands require ``GENL_ADMIN_PERM``. This is to prevent +any spamming/DoS from unauthorized userspace applications. + +List of netlink commands with possible attributes +================================================= + +Constants identifying command types for dpll device uses a +``DPLL_CMD_`` prefix and suffix according to command purpose. +The dpll device related attributes use a ``DPLL_A_`` prefix and +suffix according to attribute purpose. + + ==================================== ================================= + ``DPLL_CMD_DEVICE_ID_GET`` command to get device ID + ``DPLL_A_MODULE_NAME`` attr module name of registerer + ``DPLL_A_CLOCK_ID`` attr Unique Clock Identifier + (EUI-64), as defined by the + IEEE 1588 standard + ``DPLL_A_TYPE`` attr type of dpll device + ==================================== ================================= + + ==================================== ================================= + ``DPLL_CMD_DEVICE_GET`` command to get device info or + dump list of available devices + ``DPLL_A_ID`` attr unique dpll device ID + ``DPLL_A_MODULE_NAME`` attr module name of registerer + ``DPLL_A_CLOCK_ID`` attr Unique Clock Identifier + (EUI-64), as defined by the + IEEE 1588 standard + ``DPLL_A_MODE`` attr selection mode + ``DPLL_A_MODE_SUPPORTED`` attr available selection modes + ``DPLL_A_LOCK_STATUS`` attr dpll device lock status + ``DPLL_A_TEMP`` attr device temperature info + ``DPLL_A_TYPE`` attr type of dpll device + ==================================== ================================= + + ==================================== ================================= + ``DPLL_CMD_DEVICE_SET`` command to set dpll device config + ``DPLL_A_ID`` attr internal dpll device index + ``DPLL_A_MODE`` attr selection mode to configure + ==================================== ================================= + +Constants identifying command types for pins uses a +``DPLL_CMD_PIN_`` prefix and suffix according to command purpose. +The pin related attributes use a ``DPLL_A_PIN_`` prefix and suffix +according to attribute purpose. + + ==================================== ================================= + ``DPLL_CMD_PIN_ID_GET`` command to get pin ID + ``DPLL_A_PIN_MODULE_NAME`` attr module name of registerer + ``DPLL_A_PIN_CLOCK_ID`` attr Unique Clock Identifier + (EUI-64), as defined by the + IEEE 1588 standard + ``DPLL_A_PIN_BOARD_LABEL`` attr pin board label provided + by registerer + ``DPLL_A_PIN_PANEL_LABEL`` attr pin panel label provided + by registerer + ``DPLL_A_PIN_PACKAGE_LABEL`` attr pin package label provided + by registerer + ``DPLL_A_PIN_TYPE`` attr type of a pin + ==================================== ================================= + + ==================================== ================================== + ``DPLL_CMD_PIN_GET`` command to get pin info or dump + list of available pins + ``DPLL_A_PIN_ID`` attr unique a pin ID + ``DPLL_A_PIN_MODULE_NAME`` attr module name of registerer + ``DPLL_A_PIN_CLOCK_ID`` attr Unique Clock Identifier + (EUI-64), as defined by the + IEEE 1588 standard + ``DPLL_A_PIN_BOARD_LABEL`` attr pin board label provided + by registerer + ``DPLL_A_PIN_PANEL_LABEL`` attr pin panel label provided + by registerer + ``DPLL_A_PIN_PACKAGE_LABEL`` attr pin package label provided + by registerer + ``DPLL_A_PIN_TYPE`` attr type of a pin + ``DPLL_A_PIN_FREQUENCY`` attr current frequency of a pin + ``DPLL_A_PIN_FREQUENCY_SUPPORTED`` nested attr provides supported + frequencies + ``DPLL_A_PIN_ANY_FREQUENCY_MIN`` attr minimum value of frequency + ``DPLL_A_PIN_ANY_FREQUENCY_MAX`` attr maximum value of frequency + ``DPLL_A_PIN_PHASE_ADJUST_MIN`` attr minimum value of phase + adjustment + ``DPLL_A_PIN_PHASE_ADJUST_MAX`` attr maximum value of phase + adjustment + ``DPLL_A_PIN_PHASE_ADJUST`` attr configured value of phase + adjustment on parent device + ``DPLL_A_PIN_PARENT_DEVICE`` nested attr for each parent device + the pin is connected with + ``DPLL_A_PIN_PARENT_ID`` attr parent dpll device id + ``DPLL_A_PIN_PRIO`` attr priority of pin on the + dpll device + ``DPLL_A_PIN_STATE`` attr state of pin on the parent + dpll device + ``DPLL_A_PIN_DIRECTION`` attr direction of a pin on the + parent dpll device + ``DPLL_A_PIN_PHASE_OFFSET`` attr measured phase difference + between a pin and parent dpll + ``DPLL_A_PIN_PARENT_PIN`` nested attr for each parent pin + the pin is connected with + ``DPLL_A_PIN_PARENT_ID`` attr parent pin id + ``DPLL_A_PIN_STATE`` attr state of pin on the parent + pin + ``DPLL_A_PIN_CAPABILITIES`` attr bitmask of pin capabilities + ==================================== ================================== + + ==================================== ================================= + ``DPLL_CMD_PIN_SET`` command to set pins configuration + ``DPLL_A_PIN_ID`` attr unique a pin ID + ``DPLL_A_PIN_FREQUENCY`` attr requested frequency of a pin + ``DPLL_A_PIN_PHASE_ADJUST`` attr requested value of phase + adjustment on parent device + ``DPLL_A_PIN_PARENT_DEVICE`` nested attr for each parent dpll + device configuration request + ``DPLL_A_PIN_PARENT_ID`` attr parent dpll device id + ``DPLL_A_PIN_DIRECTION`` attr requested direction of a pin + ``DPLL_A_PIN_PRIO`` attr requested priority of pin on + the dpll device + ``DPLL_A_PIN_STATE`` attr requested state of pin on + the dpll device + ``DPLL_A_PIN_PARENT_PIN`` nested attr for each parent pin + configuration request + ``DPLL_A_PIN_PARENT_ID`` attr parent pin id + ``DPLL_A_PIN_STATE`` attr requested state of pin on + parent pin + ==================================== ================================= + +Netlink dump requests +===================== + +The ``DPLL_CMD_DEVICE_GET`` and ``DPLL_CMD_PIN_GET`` commands are +capable of dump type netlink requests, in which case the response is in +the same format as for their ``do`` request, but every device or pin +registered in the system is returned. + +SET commands format +=================== + +``DPLL_CMD_DEVICE_SET`` - to target a dpll device, the user provides +``DPLL_A_ID``, which is unique identifier of dpll device in the system, +as well as parameter being configured (``DPLL_A_MODE``). + +``DPLL_CMD_PIN_SET`` - to target a pin user must provide a +``DPLL_A_PIN_ID``, which is unique identifier of a pin in the system. +Also configured pin parameters must be added. +If ``DPLL_A_PIN_FREQUENCY`` is configured, this affects all the dpll +devices that are connected with the pin, that is why frequency attribute +shall not be enclosed in ``DPLL_A_PIN_PARENT_DEVICE``. +Other attributes: ``DPLL_A_PIN_PRIO``, ``DPLL_A_PIN_STATE`` or +``DPLL_A_PIN_DIRECTION`` must be enclosed in +``DPLL_A_PIN_PARENT_DEVICE`` as their configuration relates to only one +of parent dplls, targeted by ``DPLL_A_PIN_PARENT_ID`` attribute which is +also required inside that nest. +For MUX-type pins the ``DPLL_A_PIN_STATE`` attribute is configured in +similar way, by enclosing required state in ``DPLL_A_PIN_PARENT_PIN`` +nested attribute and targeted parent pin id in ``DPLL_A_PIN_PARENT_ID``. + +In general, it is possible to configure multiple parameters at once, but +internally each parameter change will be invoked separately, where order +of configuration is not guaranteed by any means. + +Configuration pre-defined enums +=============================== + +.. kernel-doc:: include/uapi/linux/dpll.h + +Notifications +============= + +dpll device can provide notifications regarding status changes of the +device, i.e. lock status changes, input/output changes or other alarms. +There is one multicast group that is used to notify user-space apps via +netlink socket: ``DPLL_MCGRP_MONITOR`` + +Notifications messages: + + ============================== ===================================== + ``DPLL_CMD_DEVICE_CREATE_NTF`` dpll device was created + ``DPLL_CMD_DEVICE_DELETE_NTF`` dpll device was deleted + ``DPLL_CMD_DEVICE_CHANGE_NTF`` dpll device has changed + ``DPLL_CMD_PIN_CREATE_NTF`` dpll pin was created + ``DPLL_CMD_PIN_DELETE_NTF`` dpll pin was deleted + ``DPLL_CMD_PIN_CHANGE_NTF`` dpll pin has changed + ============================== ===================================== + +Events format is the same as for the corresponding get command. +Format of ``DPLL_CMD_DEVICE_`` events is the same as response of +``DPLL_CMD_DEVICE_GET``. +Format of ``DPLL_CMD_PIN_`` events is same as response of +``DPLL_CMD_PIN_GET``. + +Device driver implementation +============================ + +Device is allocated by dpll_device_get() call. Second call with the +same arguments will not create new object but provides pointer to +previously created device for given arguments, it also increases +refcount of that object. +Device is deallocated by dpll_device_put() call, which first +decreases the refcount, once refcount is cleared the object is +destroyed. + +Device should implement set of operations and register device via +dpll_device_register() at which point it becomes available to the +users. Multiple driver instances can obtain reference to it with +dpll_device_get(), as well as register dpll device with their own +ops and priv. + +The pins are allocated separately with dpll_pin_get(), it works +similarly to dpll_device_get(). Function first creates object and then +for each call with the same arguments only the object refcount +increases. Also dpll_pin_put() works similarly to dpll_device_put(). + +A pin can be registered with parent dpll device or parent pin, depending +on hardware needs. Each registration requires registerer to provide set +of pin callbacks, and private data pointer for calling them: + +- dpll_pin_register() - register pin with a dpll device, +- dpll_pin_on_pin_register() - register pin with another MUX type pin. + +Notifications of adding or removing dpll devices are created within +subsystem itself. +Notifications about registering/deregistering pins are also invoked by +the subsystem. +Notifications about status changes either of dpll device or a pin are +invoked in two ways: + +- after successful change was requested on dpll subsystem, the subsystem + calls corresponding notification, +- requested by device driver with dpll_device_change_ntf() or + dpll_pin_change_ntf() when driver informs about the status change. + +The device driver using dpll interface is not required to implement all +the callback operation. Nevertheless, there are few required to be +implemented. +Required dpll device level callback operations: + +- ``.mode_get``, +- ``.lock_status_get``. + +Required pin level callback operations: + +- ``.state_on_dpll_get`` (pins registered with dpll device), +- ``.state_on_pin_get`` (pins registered with parent pin), +- ``.direction_get``. + +Every other operation handler is checked for existence and +``-EOPNOTSUPP`` is returned in case of absence of specific handler. + +The simplest implementation is in the OCP TimeCard driver. The ops +structures are defined like this: + +.. code-block:: c + + static const struct dpll_device_ops dpll_ops = { + .lock_status_get = ptp_ocp_dpll_lock_status_get, + .mode_get = ptp_ocp_dpll_mode_get, + .mode_supported = ptp_ocp_dpll_mode_supported, + }; + + static const struct dpll_pin_ops dpll_pins_ops = { + .frequency_get = ptp_ocp_dpll_frequency_get, + .frequency_set = ptp_ocp_dpll_frequency_set, + .direction_get = ptp_ocp_dpll_direction_get, + .direction_set = ptp_ocp_dpll_direction_set, + .state_on_dpll_get = ptp_ocp_dpll_state_get, + }; + +The registration part is then looks like this part: + +.. code-block:: c + + clkid = pci_get_dsn(pdev); + bp->dpll = dpll_device_get(clkid, 0, THIS_MODULE); + if (IS_ERR(bp->dpll)) { + err = PTR_ERR(bp->dpll); + dev_err(&pdev->dev, "dpll_device_alloc failed\n"); + goto out; + } + + err = dpll_device_register(bp->dpll, DPLL_TYPE_PPS, &dpll_ops, bp); + if (err) + goto out; + + for (i = 0; i < OCP_SMA_NUM; i++) { + bp->sma[i].dpll_pin = dpll_pin_get(clkid, i, THIS_MODULE, &bp->sma[i].dpll_prop); + if (IS_ERR(bp->sma[i].dpll_pin)) { + err = PTR_ERR(bp->dpll); + goto out_dpll; + } + + err = dpll_pin_register(bp->dpll, bp->sma[i].dpll_pin, &dpll_pins_ops, + &bp->sma[i]); + if (err) { + dpll_pin_put(bp->sma[i].dpll_pin); + goto out_dpll; + } + } + +In the error path we have to rewind every allocation in the reverse order: + +.. code-block:: c + + while (i) { + --i; + dpll_pin_unregister(bp->dpll, bp->sma[i].dpll_pin, &dpll_pins_ops, &bp->sma[i]); + dpll_pin_put(bp->sma[i].dpll_pin); + } + dpll_device_put(bp->dpll); + +More complex example can be found in Intel's ICE driver or nVidia's mlx5 driver. + +SyncE enablement +================ +For SyncE enablement it is required to allow control over dpll device +for a software application which monitors and configures the inputs of +dpll device in response to current state of a dpll device and its +inputs. +In such scenario, dpll device input signal shall be also configurable +to drive dpll with signal recovered from the PHY netdevice. +This is done by exposing a pin to the netdevice - attaching pin to the +netdevice itself with +``netdev_dpll_pin_set(struct net_device *dev, struct dpll_pin *dpll_pin)``. +Exposed pin id handle ``DPLL_A_PIN_ID`` is then identifiable by the user +as it is attached to rtnetlink respond to get ``RTM_NEWLINK`` command in +nested attribute ``IFLA_DPLL_PIN``. diff --git a/Documentation/driver-api/driver-model/devres.rst b/Documentation/driver-api/driver-model/devres.rst index 8be086b3f829..c5f99d834ec5 100644 --- a/Documentation/driver-api/driver-model/devres.rst +++ b/Documentation/driver-api/driver-model/devres.rst @@ -322,10 +322,8 @@ IOMAP devm_platform_ioremap_resource_byname() devm_platform_get_and_ioremap_resource() devm_iounmap() - pcim_iomap() - pcim_iomap_regions() : do request_region() and iomap() on multiple BARs - pcim_iomap_table() : array of mapped addresses indexed by BAR - pcim_iounmap() + + Note: For the PCI devices the specific pcim_*() functions may be used, see below. IRQ devm_free_irq() @@ -392,8 +390,16 @@ PCI devm_pci_alloc_host_bridge() : managed PCI host bridge allocation devm_pci_remap_cfgspace() : ioremap PCI configuration space devm_pci_remap_cfg_resource() : ioremap PCI configuration space resource + pcim_enable_device() : after success, all PCI ops become managed + pcim_iomap() : do iomap() on a single BAR + pcim_iomap_regions() : do request_region() and iomap() on multiple BARs + pcim_iomap_regions_request_all() : do request_region() on all and iomap() on multiple BARs + pcim_iomap_table() : array of mapped addresses indexed by BAR + pcim_iounmap() : do iounmap() on a single BAR + pcim_iounmap_regions() : do iounmap() and release_region() on multiple BARs pcim_pin_device() : keep PCI device enabled after release + pcim_set_mwi() : enable Memory-Write-Invalidate PCI transaction PHY devm_usb_get_phy() diff --git a/Documentation/driver-api/gpio/consumer.rst b/Documentation/driver-api/gpio/consumer.rst index de6fc79ad6f0..3e588b9d678c 100644 --- a/Documentation/driver-api/gpio/consumer.rst +++ b/Documentation/driver-api/gpio/consumer.rst @@ -29,6 +29,10 @@ warnings. These stubs are used for two use cases: will use it under other compile-time configurations. In this case the consumer must make sure not to call into these functions, or the user will be met with console warnings that may be perceived as intimidating. + Combining truly optional GPIOLIB usage with calls to + ``[devm_]gpiod_get_optional()`` is a *bad idea*, and will result in weird + error messages. Use the ordinary getter functions with optional GPIOLIB: + some open coding of error handling should be expected when you do this. All the functions that work with the descriptor-based GPIO interface are prefixed with ``gpiod_``. The ``gpio_`` prefix is used for the legacy diff --git a/Documentation/driver-api/i3c/protocol.rst b/Documentation/driver-api/i3c/protocol.rst index 02653defa011..23a0b93c62b1 100644 --- a/Documentation/driver-api/i3c/protocol.rst +++ b/Documentation/driver-api/i3c/protocol.rst @@ -71,8 +71,8 @@ During DAA, each I3C device reports 3 important things: related capabilities * DCR: Device Characteristic Register. This 8-bit register describes the functionalities provided by the device -* Provisional ID: A 48-bit unique identifier. On a given bus there should be no - Provisional ID collision, otherwise the discovery mechanism may fail. +* Provisioned ID: A 48-bit unique identifier. On a given bus there should be no + Provisioned ID collision, otherwise the discovery mechanism may fail. I3C slave events ================ diff --git a/Documentation/driver-api/index.rst b/Documentation/driver-api/index.rst index 1e16a40da3ba..f549a68951d7 100644 --- a/Documentation/driver-api/index.rst +++ b/Documentation/driver-api/index.rst @@ -114,6 +114,7 @@ available subsections can be seen below. zorro hte/index wmi + dpll .. only:: subproject and html diff --git a/Documentation/driver-api/pps.rst b/Documentation/driver-api/pps.rst index 2d6b99766ee8..78dded03e5d8 100644 --- a/Documentation/driver-api/pps.rst +++ b/Documentation/driver-api/pps.rst @@ -200,11 +200,17 @@ Generators Sometimes one needs to be able not only to catch PPS signals but to produce them also. For example, running a distributed simulation, which requires -computers' clock to be synchronized very tightly. One way to do this is to -invent some complicated hardware solutions but it may be neither necessary -nor affordable. The cheap way is to load a PPS generator on one of the -computers (master) and PPS clients on others (slaves), and use very simple -cables to deliver signals using parallel ports, for example. +computers' clock to be synchronized very tightly. + + +Parallel port generator +------------------------ + +One way to do this is to invent some complicated hardware solutions but it +may be neither necessary nor affordable. The cheap way is to load a PPS +generator on one of the computers (master) and PPS clients on others +(slaves), and use very simple cables to deliver signals using parallel +ports, for example. Parallel port cable pinout:: diff --git a/Documentation/driver-api/pwm.rst b/Documentation/driver-api/pwm.rst index 3fdc95f7a1d1..bb264490a87a 100644 --- a/Documentation/driver-api/pwm.rst +++ b/Documentation/driver-api/pwm.rst @@ -111,13 +111,13 @@ channel that was exported. The following properties will then be available: duty_cycle The active time of the PWM signal (read/write). - Value is in nanoseconds and must be less than the period. + Value is in nanoseconds and must be less than or equal to the period. polarity Changes the polarity of the PWM signal (read/write). Writes to this property only work if the PWM chip supports changing - the polarity. The polarity can only be changed if the PWM is not - enabled. Value is the string "normal" or "inversed". + the polarity. + Value is the string "normal" or "inversed". enable Enable/disable the PWM signal (read/write). diff --git a/Documentation/driver-api/thermal/intel_dptf.rst b/Documentation/driver-api/thermal/intel_dptf.rst index 9ab4316322a1..8fb8c5b2d685 100644 --- a/Documentation/driver-api/thermal/intel_dptf.rst +++ b/Documentation/driver-api/thermal/intel_dptf.rst @@ -164,6 +164,16 @@ ABI. ``power_limit_1_tmax_us`` (RO) Maximum powercap sysfs constraint_1_time_window_us for Intel RAPL +``power_floor_status`` (RO) + When set to 1, the power floor of the system in the current + configuration has been reached. It needs to be reconfigured to allow + power to be reduced any further. + +``power_floor_enable`` (RW) + When set to 1, enable reading and notification of the power floor + status. Notifications are triggered for the power_floor_status + attribute value changes. + :file:`/sys/bus/pci/devices/0000\:00\:04.0/` ``tcc_offset_degree_celsius`` (RW) @@ -315,3 +325,57 @@ DPTF Fan Control ---------------------------------------- Refer to Documentation/admin-guide/acpi/fan_performance_states.rst + +Workload Type Hints +---------------------------------------- + +The firmware in Meteor Lake processor generation is capable of identifying +workload type and passing hints regarding it to the OS. A special sysfs +interface is provided to allow user space to obtain workload type hints from +the firmware and control the rate at which they are provided. + +User space can poll attribute "workload_type_index" for the current hint or +can receive a notification whenever the value of this attribute is updated. + +file:`/sys/bus/pci/devices/0000:00:04.0/workload_hint/` +Segment 0, bus 0, device 4, function 0 is reserved for the processor thermal +device on all Intel client processors. So, the above path doesn't change +based on the processor generation. + +``workload_hint_enable`` (RW) + Enable firmware to send workload type hints to user space. + +``notification_delay_ms`` (RW) + Minimum delay in milliseconds before firmware will notify OS. This is + for the rate control of notifications. This delay is between changing + the workload type prediction in the firmware and notifying the OS about + the change. The default delay is 1024 ms. The delay of 0 is invalid. + The delay is rounded up to the nearest power of 2 to simplify firmware + programming of the delay value. The read of notification_delay_ms + attribute shows the effective value used. + +``workload_type_index`` (RO) + Predicted workload type index. User space can get notification of + change via existing sysfs attribute change notification mechanism. + + The supported index values and their meaning for the Meteor Lake + processor generation are as follows: + + 0 - Idle: System performs no tasks, power and idle residency are + consistently low for long periods of time. + + 1 – Battery Life: Power is relatively low, but the processor may + still be actively performing a task, such as video playback for + a long period of time. + + 2 – Sustained: Power level that is relatively high for a long period + of time, with very few to no periods of idleness, which will + eventually exhaust RAPL Power Limit 1 and 2. + + 3 – Bursty: Consumes a relatively constant average amount of power, but + periods of relative idleness are interrupted by bursts of + activity. The bursts are relatively short and the periods of + relative idleness between them typically prevent RAPL Power + Limit 1 from being exhausted. + + 4 – Unknown: Can't classify. diff --git a/Documentation/driver-api/tty/index.rst b/Documentation/driver-api/tty/index.rst index 2d32606a4278..b490da11f257 100644 --- a/Documentation/driver-api/tty/index.rst +++ b/Documentation/driver-api/tty/index.rst @@ -36,6 +36,7 @@ In-detail description of the named TTY structures is in separate documents: tty_struct tty_ldisc tty_buffer + tty_ioctl tty_internals Writing TTY Driver diff --git a/Documentation/driver-api/tty/tty_ioctl.rst b/Documentation/driver-api/tty/tty_ioctl.rst new file mode 100644 index 000000000000..3ff1ac5e07f1 --- /dev/null +++ b/Documentation/driver-api/tty/tty_ioctl.rst @@ -0,0 +1,10 @@ +.. SPDX-License-Identifier: GPL-2.0 + +================= +TTY IOCTL Helpers +================= + +.. kernel-doc:: drivers/tty/tty_ioctl.c + +.. kernel-doc:: include/linux/tty.h + :identifiers: tty_get_baud_rate diff --git a/Documentation/driver-api/usb/dma.rst b/Documentation/driver-api/usb/dma.rst index d32c27e11b90..02f6825ff830 100644 --- a/Documentation/driver-api/usb/dma.rst +++ b/Documentation/driver-api/usb/dma.rst @@ -93,44 +93,18 @@ DMA address space of the device. However, most buffers passed to your driver can safely be used with such DMA mapping. (See the first section of Documentation/core-api/dma-api-howto.rst, titled "What memory is DMA-able?") -- When you're using scatterlists, you can map everything at once. On some - systems, this kicks in an IOMMU and turns the scatterlists into single - DMA transactions:: +- When you have the scatterlists which have been mapped for the USB controller, + you could use the new ``usb_sg_*()`` calls, which would turn scatterlist + into URBs:: - int usb_buffer_map_sg (struct usb_device *dev, unsigned pipe, - struct scatterlist *sg, int nents); + int usb_sg_init(struct usb_sg_request *io, struct usb_device *dev, + unsigned pipe, unsigned period, struct scatterlist *sg, + int nents, size_t length, gfp_t mem_flags); - void usb_buffer_dmasync_sg (struct usb_device *dev, unsigned pipe, - struct scatterlist *sg, int n_hw_ents); + void usb_sg_wait(struct usb_sg_request *io); - void usb_buffer_unmap_sg (struct usb_device *dev, unsigned pipe, - struct scatterlist *sg, int n_hw_ents); + void usb_sg_cancel(struct usb_sg_request *io); - It's probably easier to use the new ``usb_sg_*()`` calls, which do the DMA - mapping and apply other tweaks to make scatterlist i/o be fast. - -- Some drivers may prefer to work with the model that they're mapping large - buffers, synchronizing their safe re-use. (If there's no re-use, then let - usbcore do the map/unmap.) Large periodic transfers make good examples - here, since it's cheaper to just synchronize the buffer than to unmap it - each time an urb completes and then re-map it on during resubmission. - - These calls all work with initialized urbs: ``urb->dev``, ``urb->pipe``, - ``urb->transfer_buffer``, and ``urb->transfer_buffer_length`` must all be - valid when these calls are used (``urb->setup_packet`` must be valid too - if urb is a control request):: - - struct urb *usb_buffer_map (struct urb *urb); - - void usb_buffer_dmasync (struct urb *urb); - - void usb_buffer_unmap (struct urb *urb); - - The calls manage ``urb->transfer_dma`` for you, and set - ``URB_NO_TRANSFER_DMA_MAP`` so that usbcore won't map or unmap the buffer. - They cannot be used for setup_packet buffers in control requests. - -Note that several of those interfaces are currently commented out, since -they don't have current users. See the source code. Other than the dmasync -calls (where the underlying DMA primitives have changed), most of them can -easily be commented back in if you want to use them. + When the USB controller doesn't support DMA, the ``usb_sg_init()`` would try + to submit URBs in PIO way as long as the page in scatterlists is not in the + Highmem, which could be very rare in modern architectures. |