From eda15425bcd2703ea1cfeebd65847305c17e5f0a Mon Sep 17 00:00:00 2001 From: John Crispin Date: Wed, 27 Mar 2013 18:38:48 +0100 Subject: [PATCH] owrt: GPIO: add gpio_export_with_name http://lists.infradead.org/pipermail/linux-arm-kernel/2012-November/133856.html Signed-off-by: John Crispin --- Documentation/devicetree/bindings/gpio/gpio.txt | 60 ++++++++++++++++++++++ drivers/gpio/gpiolib-of.c | 61 +++++++++++++++++++++++ drivers/gpio/gpiolib.c | 18 +++++-- include/asm-generic/gpio.h | 6 ++- include/linux/gpio.h | 23 ++++++++- 5 files changed, 160 insertions(+), 8 deletions(-) Index: linux-3.8.11/Documentation/devicetree/bindings/gpio/gpio.txt =================================================================== --- linux-3.8.11.orig/Documentation/devicetree/bindings/gpio/gpio.txt 2013-05-01 18:56:10.000000000 +0200 +++ linux-3.8.11/Documentation/devicetree/bindings/gpio/gpio.txt 2013-05-06 12:43:38.252652605 +0200 @@ -112,3 +112,63 @@ The pinctrl node must have "#gpio-range-cells" property to show number of arguments to pass with phandle from gpio controllers node. + +3) gpio-export +-------------- + +gpio-export will allow you to automatically export gpio + +required properties: +- compatible: Should be "gpio-export" + +in each child node will reprensent a gpio or if no name is specified +a list of gpio to export + +required properties: +- gpios: gpio to export + +optional properties: + - gpio-export,name: export name + - gpio-export,output: to set the as output with default value + if no present gpio as input + - pio-export,direction_may_change: boolean to allow the direction to be controllable + +Example: + + +gpio_export { + compatible = "gpio-export"; + #size-cells = <0>; + + in { + gpio-export,name = "in"; + gpios = <&pioC 20 0>; + }; + + out { + gpio-export,name = "out"; + gpio-export,output = <1>; + gpio-export,direction_may_change; + gpios = <&pioC 21 0>; + }; + + in_out { + gpio-export,name = "in_out"; + gpio-export,direction_may_change; + gpios = <&pioC 21 0>; + }; + + gpios_in { + gpios = <&pioB 0 0 + &pioB 3 0 + &pioC 4 0>; + gpio-export,direction_may_change; + }; + + gpios_out { + gpios = <&pioB 1 0 + &pioB 2 0 + &pioC 3 0>; + gpio-export,output = <1>; + }; +}; Index: linux-3.8.11/drivers/gpio/gpiolib-of.c =================================================================== --- linux-3.8.11.orig/drivers/gpio/gpiolib-of.c 2013-05-01 18:56:10.000000000 +0200 +++ linux-3.8.11/drivers/gpio/gpiolib-of.c 2013-05-06 13:35:56.452788709 +0200 @@ -21,6 +21,8 @@ #include #include #include +#include +#include /* Private data structure for of_gpiochip_find_and_xlate */ struct gg_data { @@ -288,3 +290,69 @@ if (chip->of_node) of_node_put(chip->of_node); } + +static struct of_device_id gpio_export_ids[] = { + { .compatible = "gpio-export" }, + { /* sentinel */ } +}; + +static int __init of_gpio_export_probe(struct platform_device *pdev) +{ + struct device_node *np = pdev->dev.of_node; + struct device_node *cnp; + u32 val; + int nb = 0; + + for_each_child_of_node(np, cnp) { + const char *name = NULL; + int gpio; + bool dmc; + int max_gpio = 1; + int i; + + of_property_read_string(cnp, "gpio-export,name", &name); + + if (!name) + max_gpio = of_gpio_count(cnp); + + for (i = 0; i < max_gpio; i++) { + unsigned flags = 0; + enum of_gpio_flags of_flags; + + gpio = of_get_gpio_flags(cnp, i, &of_flags); + + if (of_flags == OF_GPIO_ACTIVE_LOW) + flags |= GPIOF_ACTIVE_LOW; + + if (!of_property_read_u32(cnp, "gpio-export,output", &val)) + flags |= val ? GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW; + else + flags |= GPIOF_IN; + + if (devm_gpio_request_one(&pdev->dev, gpio, flags, name ? name : of_node_full_name(np))) + continue; + + dmc = of_property_read_bool(cnp, "gpio-export,direction_may_change"); + gpio_export_with_name(gpio, dmc, name); + nb++; + } + } + + dev_info(&pdev->dev, "%d gpio(s) exported\n", nb); + + return 0; +} + +static struct platform_driver gpio_export_driver = { + .driver = { + .name = "gpio-export", + .owner = THIS_MODULE, + .of_match_table = of_match_ptr(gpio_export_ids), + }, +}; + +static int __init of_gpio_export_init(void) +{ + return platform_driver_probe(&gpio_export_driver, of_gpio_export_probe); +} +device_initcall(of_gpio_export_init); Index: linux-3.8.11/drivers/gpio/gpiolib.c =================================================================== --- linux-3.8.11.orig/drivers/gpio/gpiolib.c 2013-05-01 18:56:10.000000000 +0200 +++ linux-3.8.11/drivers/gpio/gpiolib.c 2013-05-06 13:31:35.060777376 +0200 @@ -714,9 +714,10 @@ /** - * gpio_export - export a GPIO through sysfs + * gpio_export_with_name - export a GPIO through sysfs * @gpio: gpio to make available, already requested * @direction_may_change: true if userspace may change gpio direction + * @name: gpio name * Context: arch_initcall or later * * When drivers want to make a GPIO accessible to userspace after they @@ -728,7 +729,7 @@ * * Returns zero on success, else an error. */ -int gpio_export(unsigned gpio, bool direction_may_change) +int gpio_export_with_name(unsigned gpio, bool direction_may_change, const char *name) { unsigned long flags; struct gpio_desc *desc; @@ -762,6 +763,8 @@ goto fail_unlock; } + if (name) + ioname = name; if (!desc->chip->direction_input || !desc->chip->direction_output) direction_may_change = false; spin_unlock_irqrestore(&gpio_lock, flags); @@ -804,7 +807,7 @@ pr_debug("%s: gpio%d status %d\n", __func__, gpio, status); return status; } -EXPORT_SYMBOL_GPL(gpio_export); +EXPORT_SYMBOL_GPL(gpio_export_with_name); static int match_export(struct device *dev, void *data) { @@ -1418,6 +1421,9 @@ if (flags & GPIOF_OPEN_SOURCE) set_bit(FLAG_OPEN_SOURCE, &gpio_desc[gpio].flags); + if (flags & GPIOF_ACTIVE_LOW) + set_bit(FLAG_ACTIVE_LOW, &gpio_desc[gpio].flags); + if (flags & GPIOF_DIR_IN) err = gpio_direction_input(gpio); else Index: linux-3.8.11/include/asm-generic/gpio.h =================================================================== --- linux-3.8.11.orig/include/asm-generic/gpio.h 2013-05-01 18:56:10.000000000 +0200 +++ linux-3.8.11/include/asm-generic/gpio.h 2013-05-06 12:43:38.252652605 +0200 @@ -204,7 +204,8 @@ * A sysfs interface can be exported by individual drivers if they want, * but more typically is configured entirely from userspace. */ -extern int gpio_export(unsigned gpio, bool direction_may_change); +extern int gpio_export_with_name(unsigned gpio, bool direction_may_change, + const char *name); extern int gpio_export_link(struct device *dev, const char *name, unsigned gpio); extern int gpio_sysfs_set_active_low(unsigned gpio, int value); @@ -249,7 +250,8 @@ /* sysfs support is only available with gpiolib, where it's optional */ -static inline int gpio_export(unsigned gpio, bool direction_may_change) +static inline int gpio_export_with_name(unsigned gpio, + bool direction_may_change, const char *name) { return -ENOSYS; } Index: linux-3.8.11/include/linux/gpio.h =================================================================== --- linux-3.8.11.orig/include/linux/gpio.h 2013-05-01 18:56:10.000000000 +0200 +++ linux-3.8.11/include/linux/gpio.h 2013-05-06 13:32:59.796781050 +0200 @@ -27,6 +27,9 @@ #define GPIOF_EXPORT_DIR_FIXED (GPIOF_EXPORT) #define GPIOF_EXPORT_DIR_CHANGEABLE (GPIOF_EXPORT | GPIOF_EXPORT_CHANGEABLE) +#define GPIOF_ACTIVE_LOW (1 << 6) + + /** * struct gpio - a structure describing a GPIO with configuration * @gpio: the GPIO number @@ -189,7 +192,8 @@ WARN_ON(1); } -static inline int gpio_export(unsigned gpio, bool direction_may_change) +static inline int gpio_export_with_name(unsigned gpio, + bool direction_may_change, const char *name) { /* GPIO can never have been requested or set as {in,out}put */ WARN_ON(1); @@ -248,4 +252,24 @@ #endif /* ! CONFIG_GENERIC_GPIO */ +/** + * gpio_export - export a GPIO through sysfs + * @gpio: gpio to make available, already requested + * @direction_may_change: true if userspace may change gpio direction + * Context: arch_initcall or later + * + * When drivers want to make a GPIO accessible to userspace after they + * have requested it -- perhaps while debugging, or as part of their + * public interface -- they may use this routine. If the GPIO can + * change direction (some can't) and the caller allows it, userspace + * will see "direction" sysfs attribute which may be used to change + * the gpio's direction. A "value" attribute will always be provided. + * + * Returns zero on success, else an error. + */ +static inline int gpio_export(unsigned gpio,bool direction_may_change) +{ + return gpio_export_with_name(gpio, direction_may_change, NULL); +} + #endif /* __LINUX_GPIO_H */