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authorLinus Torvalds <torvalds@linux-foundation.org>2012-03-28 14:08:46 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-03-28 14:08:46 -0700
commit7bf97e1d5a94b6a71815771bb9452fc2c022c966 (patch)
treef89082dbd33a51a79c9a9c0dddb29e2b11b8207e /Documentation
parent30304e5a79d424eb2c8707b3ff0e9b8bf6ab3e8f (diff)
parentc77c8a6fd3d57b586ff5ecb5ab5b32ca4f54fe75 (diff)
Merge tag 'gpio-for-linus' of git://git.secretlab.ca/git/linux-2.6
Pull GPIO changes for v3.4 from Grant Likely: "Primarily gpio device driver changes with some minor side effects under arch/arm and arch/x86. Also includes a few core changes such as explicitly supporting (electrical) open source and open drain outputs and some help for parsing gpio devicetree properties." Fix up context conflict due to Laxman Dewangan adding sleep control for the tps65910 driver separately for gpio's and regulators. * tag 'gpio-for-linus' of git://git.secretlab.ca/git/linux-2.6: (34 commits) gpio/ep93xx: Remove unused inline function and useless pr_err message gpio/sodaville: Mark broken due to core irqdomain migration gpio/omap: fix redundant decoding of gpio offset gpio/omap: fix incorrect update to context.irqenable1 gpio/omap: fix incorrect context restore logic in omap_gpio_runtime_* gpio/omap: fix missing dataout context save in _set_gpio_dataout_reg gpio/omap: fix _set_gpio_irqenable implementation gpio/omap: fix trigger type to unsigned gpio/omap: fix wakeup_en register update in _set_gpio_wakeup() gpio: tegra: tegra_gpio_config shouldn't be __init gpio/davinci: fix enabling unbanked GPIO IRQs gpio/davinci: fix oops on unbanked gpio irq request gpio/omap: Fix section warning for omap_mpuio_alloc_gc() ARM: tegra: export tegra_gpio_{en,dis}able gpio/gpio-stmpe: Fix the value returned by _get_value routine Documentation/gpio.txt: Explain expected pinctrl interaction GPIO: LPC32xx: Add output reading to GPO P3 GPIO: LPC32xx: Fix missing bit selection mask gpio/omap: fix wakeups on level-triggered GPIOs gpio/omap: Fix IRQ handling for SPARSE_IRQ ...
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/devicetree/bindings/gpio/gpio-omap.txt36
-rw-r--r--Documentation/devicetree/bindings/gpio/sodaville.txt48
-rw-r--r--Documentation/gpio.txt40
3 files changed, 119 insertions, 5 deletions
diff --git a/Documentation/devicetree/bindings/gpio/gpio-omap.txt b/Documentation/devicetree/bindings/gpio/gpio-omap.txt
new file mode 100644
index 000000000000..bff51a2fee1e
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/gpio-omap.txt
@@ -0,0 +1,36 @@
+OMAP GPIO controller bindings
+
+Required properties:
+- compatible:
+ - "ti,omap2-gpio" for OMAP2 controllers
+ - "ti,omap3-gpio" for OMAP3 controllers
+ - "ti,omap4-gpio" for OMAP4 controllers
+- #gpio-cells : Should be two.
+ - first cell is the pin number
+ - second cell is used to specify optional parameters (unused)
+- gpio-controller : Marks the device node as a GPIO controller.
+- #interrupt-cells : Should be 2.
+- interrupt-controller: Mark the device node as an interrupt controller
+ 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.
+
+OMAP specific properties:
+- ti,hwmods: Name of the hwmod associated to the GPIO:
+ "gpio<X>", <X> being the 1-based instance number from the HW spec
+
+
+Example:
+
+gpio4: gpio4 {
+ compatible = "ti,omap4-gpio";
+ ti,hwmods = "gpio4";
+ #gpio-cells = <2>;
+ gpio-controller;
+ #interrupt-cells = <2>;
+ interrupt-controller;
+};
diff --git a/Documentation/devicetree/bindings/gpio/sodaville.txt b/Documentation/devicetree/bindings/gpio/sodaville.txt
new file mode 100644
index 000000000000..563eff22b975
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/sodaville.txt
@@ -0,0 +1,48 @@
+GPIO controller on CE4100 / Sodaville SoCs
+==========================================
+
+The bindings for CE4100's GPIO controller match the generic description
+which is covered by the gpio.txt file in this folder.
+
+The only additional property is the intel,muxctl property which holds the
+value which is written into the MUXCNTL register.
+
+There is no compatible property for now because the driver is probed via
+PCI id (vendor 0x8086 device 0x2e67).
+
+The interrupt specifier consists of two cells encoded as follows:
+ - <1st cell>: The interrupt-number that identifies the interrupt source.
+ - <2nd cell>: The level-sense information, encoded as follows:
+ 4 - active high level-sensitive
+ 8 - active low level-sensitive
+
+Example of the GPIO device and one user:
+
+ pcigpio: gpio@b,1 {
+ /* two cells for GPIO and interrupt */
+ #gpio-cells = <2>;
+ #interrupt-cells = <2>;
+ compatible = "pci8086,2e67.2",
+ "pci8086,2e67",
+ "pciclassff0000",
+ "pciclassff00";
+
+ reg = <0x15900 0x0 0x0 0x0 0x0>;
+ /* Interrupt line of the gpio device */
+ interrupts = <15 1>;
+ /* It is an interrupt and GPIO controller itself */
+ interrupt-controller;
+ gpio-controller;
+ intel,muxctl = <0>;
+ };
+
+ testuser@20 {
+ compatible = "example,testuser";
+ /* User the 11th GPIO line as an active high triggered
+ * level interrupt
+ */
+ interrupts = <11 8>;
+ interrupt-parent = <&pcigpio>;
+ /* Use this GPIO also with the gpio functions */
+ gpios = <&pcigpio 11 0>;
+ };
diff --git a/Documentation/gpio.txt b/Documentation/gpio.txt
index 792faa3c06cf..620a07844e8c 100644
--- a/Documentation/gpio.txt
+++ b/Documentation/gpio.txt
@@ -271,9 +271,26 @@ Some platforms may also use knowledge about what GPIOs are active for
power management, such as by powering down unused chip sectors and, more
easily, gating off unused clocks.
-Note that requesting a GPIO does NOT cause it to be configured in any
-way; it just marks that GPIO as in use. Separate code must handle any
-pin setup (e.g. controlling which pin the GPIO uses, pullup/pulldown).
+For GPIOs that use pins known to the pinctrl subsystem, that subsystem should
+be informed of their use; a gpiolib driver's .request() operation may call
+pinctrl_request_gpio(), and a gpiolib driver's .free() operation may call
+pinctrl_free_gpio(). The pinctrl subsystem allows a pinctrl_request_gpio()
+to succeed concurrently with a pin or pingroup being "owned" by a device for
+pin multiplexing.
+
+Any programming of pin multiplexing hardware that is needed to route the
+GPIO signal to the appropriate pin should occur within a GPIO driver's
+.direction_input() or .direction_output() operations, and occur after any
+setup of an output GPIO's value. This allows a glitch-free migration from a
+pin's special function to GPIO. This is sometimes required when using a GPIO
+to implement a workaround on signals typically driven by a non-GPIO HW block.
+
+Some platforms allow some or all GPIO signals to be routed to different pins.
+Similarly, other aspects of the GPIO or pin may need to be configured, such as
+pullup/pulldown. Platform software should arrange that any such details are
+configured prior to gpio_request() being called for those GPIOs, e.g. using
+the pinctrl subsystem's mapping table, so that GPIO users need not be aware
+of these details.
Also note that it's your responsibility to have stopped using a GPIO
before you free it.
@@ -302,6 +319,8 @@ where 'flags' is currently defined to specify the following properties:
* GPIOF_INIT_LOW - as output, set initial level to LOW
* GPIOF_INIT_HIGH - as output, set initial level to HIGH
+ * GPIOF_OPEN_DRAIN - gpio pin is open drain type.
+ * GPIOF_OPEN_SOURCE - gpio pin is open source type.
since GPIOF_INIT_* are only valid when configured as output, so group valid
combinations as:
@@ -310,8 +329,19 @@ combinations as:
* GPIOF_OUT_INIT_LOW - configured as output, initial level LOW
* GPIOF_OUT_INIT_HIGH - configured as output, initial level HIGH
-In the future, these flags can be extended to support more properties such
-as open-drain status.
+When setting the flag as GPIOF_OPEN_DRAIN then it will assume that pins is
+open drain type. Such pins will not be driven to 1 in output mode. It is
+require to connect pull-up on such pins. By enabling this flag, gpio lib will
+make the direction to input when it is asked to set value of 1 in output mode
+to make the pin HIGH. The pin is make to LOW by driving value 0 in output mode.
+
+When setting the flag as GPIOF_OPEN_SOURCE then it will assume that pins is
+open source type. Such pins will not be driven to 0 in output mode. It is
+require to connect pull-down on such pin. By enabling this flag, gpio lib will
+make the direction to input when it is asked to set value of 0 in output mode
+to make the pin LOW. The pin is make to HIGH by driving value 1 in output mode.
+
+In the future, these flags can be extended to support more properties.
Further more, to ease the claim/release of multiple GPIOs, 'struct gpio' is
introduced to encapsulate all three fields as: