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authorSimon Arlott <simon@fire.lp0.eu>2012-09-28 08:10:11 +0400
committerLinus Walleij <linus.walleij@linaro.org>2012-10-01 10:05:22 +0400
commite1b2dc70cd5b00e17c703163a463d82354b1cc76 (patch)
treefc013a598baa611ba6651b760f8a03347b2d6e47 /Documentation/devicetree
parentb0e181d0944e858ae0cacf808752e791894c5651 (diff)
downloadlinux-e1b2dc70cd5b00e17c703163a463d82354b1cc76.tar.xz
pinctrl: add bcm2835 driver
The BCM2835 GPIO module is a combined GPIO controller, (GPIO) interrupt controller, and pinmux/control device. Original driver by Simon Arlott. Rewrite including GPIO chip device by Chris Boot. Upstreaming changes by Stephen Warren: * Wrote DT binding documentation. * Changed brcm,function to an integer to more directly match the datasheet, and to match brcm,pins being an integer. * Implemented pull-up/down pin config. * Removed read-only DT property and related code. The restriction this implemented are driven by the board, not the GPIO HW block, so don't really make sense of a HW block binding, were in general incomplete (since they could only know about the few pins hard-coded into the Raspberry Pi B board design and not the uncommitted GPIOS), and are better represented simply by not writing incorrect data into pin configuration nodes. * Don't set GPIO_IN function select in gpio_request_enable() to avoid glitches; defer this to gpio_set_direction(). Consequently, removed empty bcm2835_pmx_gpio_request_enable(). * Simplified enabled_irq_map[]; make it explicitly 1 entry per bank. * Lifted use of enabled_irq_map[] outside the per-interrupt loop in IRQ handler, thus fixing an issue where the code was indexing into enabled_irq_map[] by intra-bank GPIO ID, not global GPIO ID. * Removed locking in IRQ handler, since all other code uses spin_lock_irqsave() and so guarantees it doesn't run concurrently with the handler. * Moved duplicated BUILD_BUG_ON()s into probe(). Also check size of bcm2835_gpio_pins[]. * Remove range-checking from bcm2835_pctl_get_groups_count() since we've decided to trust the pinctrl core. * Made bcm2835_pmx_gpio_disable_free() call bcm2835_pinctrl_fsel_set() directly for simplicity. * Fixed body of dt_free_map() to match latest dt_node_to_map(). * Removed GPIO ownership check from bcm2835_pmx_enable() since the pinctrl core owns doing this. * Made irq_chip and pinctrl_gpio_range .name == MODULE_NAME so it's more descriptive. * Simplified remove(); removed call to non-existent pinctrl_remove_gpio_range(), remove early return on error. * Don't force gpiochip's base to 0. Set gpio_range.base to gpiochip's base GPIO number. * Error-handling cleanups in probe(). * Switched to module_platform_driver() rather than open-coding. * Made pin, group, and function names lower-case. * s/broadcom/brcm/ in DT property names. * s/2708/2835/. * Fixed a couple minor checkpatch warnings, and other minor cleanup. Signed-off-by: Simon Arlott <simon@fire.lp0.eu> Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
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-rw-r--r--Documentation/devicetree/bindings/pinctrl/brcm,bcm2835-gpio.txt74
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diff --git a/Documentation/devicetree/bindings/pinctrl/brcm,bcm2835-gpio.txt b/Documentation/devicetree/bindings/pinctrl/brcm,bcm2835-gpio.txt
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+Broadcom BCM2835 GPIO (and pinmux) controller
+
+The BCM2835 GPIO module is a combined GPIO controller, (GPIO) interrupt
+controller, and pinmux/control device.
+
+Required properties:
+- compatible: "brcm,bcm2835-gpio"
+- reg: Should contain the physical address of the GPIO module's registes.
+- gpio-controller: Marks the device node as a GPIO controller.
+- #gpio-cells : Should be two. The first cell is the pin number and the
+ second cell is used to specify optional parameters:
+ - bit 0 specifies polarity (0 for normal, 1 for inverted)
+- interrupts : The interrupt outputs from the controller. One interrupt per
+ individual bank followed by the "all banks" interrupt.
+- interrupt-controller: Marks the device node as an interrupt controller.
+- #interrupt-cells : Should be 2.
+ The first cell is the GPIO number.
+ The second cell is used to specify flags:
+ bits[3:0] trigger type and level flags:
+ 1 = low-to-high edge triggered.
+ 2 = high-to-low edge triggered.
+ 4 = active high level-sensitive.
+ 8 = active low level-sensitive.
+ Valid combinations are 1, 2, 3, 4, 8.
+
+Please refer to ../gpio/gpio.txt for a general description of GPIO bindings.
+
+Please refer to pinctrl-bindings.txt in this directory for details of the
+common pinctrl bindings used by client devices, including the meaning of the
+phrase "pin configuration node".
+
+Each pin configuration node lists the pin(s) to which it applies, and one or
+more of the mux function to select on those pin(s), and pull-up/down
+configuration. Each subnode only affects those parameters that are explicitly
+listed. In other words, a subnode that lists only a mux function implies no
+information about any pull configuration. Similarly, a subnode that lists only
+a pul parameter implies no information about the mux function.
+
+Required subnode-properties:
+- brcm,pins: An array of cells. Each cell contains the ID of a pin. Valid IDs
+ are the integer GPIO IDs; 0==GPIO0, 1==GPIO1, ... 53==GPIO53.
+
+Optional subnode-properties:
+- brcm,function: Integer, containing the function to mux to the pin(s):
+ 0: GPIO in
+ 1: GPIO out
+ 2: alt5
+ 3: alt4
+ 4: alt0
+ 5: alt1
+ 6: alt2
+ 7: alt3
+- brcm,pull: Integer, representing the pull-down/up to apply to the pin(s):
+ 0: none
+ 1: down
+ 2: up
+
+Each of brcm,function and brcm,pull may contain either a single value which
+will be applied to all pins in brcm,pins, or 1 value for each entry in
+brcm,pins.
+
+Example:
+
+ gpio: gpio {
+ compatible = "brcm,bcm2835-gpio";
+ reg = <0x2200000 0xb4>;
+ interrupts = <2 17>, <2 19>, <2 18>, <2 20>;
+
+ gpio-controller;
+ #gpio-cells = <2>;
+
+ interrupt-controller;
+ #interrupt-cells = <2>;
+ };