pinctrl: Add documentation for pinctrl-msm8x74

This adds initial documentation for the pinctrl-msm8x74 driver.

Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Bjorn Andersson 2013-12-05 18:10:05 -08:00 committed by Linus Walleij
parent 55aaf8342d
commit d46f421608

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Qualcomm MSM8x74 TLMM block
Required properties:
- compatible: "qcom,msm8x74-pinctrl"
- reg: Should be the base address and length of the TLMM block.
- interrupts: Should be the parent IRQ of the TLMM block.
- interrupt-controller: Marks the device node as an interrupt controller.
- #interrupt-cells: Should be two.
- gpio-controller: Marks the device node as a GPIO controller.
- #gpio-cells : Should be two.
The first cell is the gpio pin number and the
second cell is used for optional parameters.
Please refer to ../gpio/gpio.txt and ../interrupt-controller/interrupts.txt for
a general description of GPIO and interrupt 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".
Qualcomm's pin configuration nodes act as a container for an abitrary number of
subnodes. Each of these subnodes represents some desired configuration for a
pin, a group, or a list of pins or groups. This configuration can include the
mux function to select on those pin(s)/group(s), and various pin configuration
parameters, such as pull-up, drive strength, etc.
The name of each subnode is not important; all subnodes should be enumerated
and processed purely based on their content.
Each subnode only affects those parameters that are explicitly listed. In
other words, a subnode that lists a mux function but no pin configuration
parameters implies no information about any pin configuration parameters.
Similarly, a pin subnode that describes a pullup parameter implies no
information about e.g. the mux function.
The following generic properties as defined in pinctrl-bindings.txt are valid
to specify in a pin configuration subnode:
pins, function, bias-disable, bias-pull-down, bias-pull,up, drive-strength.
Non-empty subnodes must specify the 'pins' property.
Note that not all properties are valid for all pins.
Valid values for qcom,pins are:
gpio0-gpio145
Supports mux, bias and drive-strength
sdc1_clk, sdc1_cmd, sdc1_data, sdc2_clk, sdc2_cmd, sdc2_data
Supports bias and drive-strength
Valid values for qcom,function are:
blsp_i2c2, blsp_i2c6, blsp_i2c11, blsp_spi1, blsp_uart2, blsp_uart8, slimbus
(Note that this is not yet the complete list of functions)
Example:
msmgpio: pinctrl@fd510000 {
compatible = "qcom,msm8x74-pinctrl";
reg = <0xfd510000 0x4000>;
gpio-controller;
#gpio-cells = <2>;
interrupt-controller;
#interrupt-cells = <2>;
interrupts = <0 208 0>;
pinctrl-names = "default";
pinctrl-0 = <&uart2_default>;
uart2_default: uart2_default {
mux {
qcom,pins = "gpio4", "gpio5";
qcom,function = "blsp_uart2";
};
tx {
qcom,pins = "gpio4";
drive-strength = <4>;
bias-disable;
};
rx {
qcom,pins = "gpio5";
drive-strength = <2>;
bias-pull-up;
};
};
};