target/linux/ramips/patches-3.8/0209-owrt-GPIO-add-gpio_export_with_name.patch

   1 From eda15425bcd2703ea1cfeebd65847305c17e5f0a Mon Sep 17 00:00:00 2001
   2 From: John Crispin <blogic@openwrt.org>
   3 Date: Wed, 27 Mar 2013 18:38:48 +0100
   4 Subject: [PATCH] owrt: GPIO: add gpio_export_with_name
   5
   6 http://lists.infradead.org/pipermail/linux-arm-kernel/2012-November/133856.html
   7
   8 Signed-off-by: John Crispin <blogic@openwrt.org>
   9 ---
  10  Documentation/devicetree/bindings/gpio/gpio.txt |   60 ++++++++++++++++++++++
  11  drivers/gpio/gpiolib-of.c                       |   61 +++++++++++++++++++++++
  12  drivers/gpio/gpiolib.c                          |   18 +++++--
  13  include/asm-generic/gpio.h                      |    6 ++-
  14  include/linux/gpio.h                            |   23 ++++++++-
  15  5 files changed, 160 insertions(+), 8 deletions(-)
  16
  17 --- a/Documentation/devicetree/bindings/gpio/gpio.txt
  18 +++ b/Documentation/devicetree/bindings/gpio/gpio.txt
  19 @@ -112,3 +112,63 @@ where,
  20
  21  The pinctrl node must have "#gpio-range-cells" property to show number of
  22  arguments to pass with phandle from gpio controllers node.
  23 +
  24 +3) gpio-export
  25 +--------------
  26 +
  27 +gpio-export will allow you to automatically export gpio
  28 +
  29 +required properties:
  30 +- compatible: Should be "gpio-export"
  31 +
  32 +in each child node will reprensent a gpio or if no name is specified
  33 +a list of gpio to export
  34 +
  35 +required properties:
  36 +- gpios: gpio to export
  37 +
  38 +optional properties:
  39 + - gpio-export,name: export name
  40 + - gpio-export,output: to set the as output with default value
  41 +                      if no present gpio as input
  42 + - pio-export,direction_may_change: boolean to allow the direction to be controllable
  43 +
  44 +Example:
  45 +
  46 +
  47 +gpio_export {
  48 +       compatible = "gpio-export";
  49 +       #size-cells = <0>;
  50 +
  51 +       in {
  52 +               gpio-export,name = "in";
  53 +               gpios = <&pioC 20 0>;
  54 +       };
  55 +
  56 +       out {
  57 +               gpio-export,name = "out";
  58 +               gpio-export,output = <1>;
  59 +               gpio-export,direction_may_change;
  60 +               gpios = <&pioC 21 0>;
  61 +       };
  62 +
  63 +       in_out {
  64 +               gpio-export,name = "in_out";
  65 +               gpio-export,direction_may_change;
  66 +               gpios = <&pioC 21 0>;
  67 +       };
  68 +
  69 +       gpios_in {
  70 +               gpios = <&pioB 0 0
  71 +                        &pioB 3 0
  72 +                        &pioC 4 0>;
  73 +               gpio-export,direction_may_change;
  74 +       };
  75 +
  76 +       gpios_out {
  77 +               gpios = <&pioB 1 0
  78 +                        &pioB 2 0
  79 +                        &pioC 3 0>;
  80 +               gpio-export,output = <1>;
  81 +       };
  82 +};
  83 --- a/drivers/gpio/gpiolib-of.c
  84 +++ b/drivers/gpio/gpiolib-of.c
  85 @@ -21,6 +21,8 @@
  86  #include <linux/of_gpio.h>
  87  #include <linux/pinctrl/pinctrl.h>
  88  #include <linux/slab.h>
  89 +#include <linux/init.h>
  90 +#include <linux/platform_device.h>
  91
  92  /* Private data structure for of_gpiochip_find_and_xlate */
  93  struct gg_data {
  94 @@ -289,3 +291,62 @@ void of_gpiochip_remove(struct gpio_chip
  95         if (chip->of_node)
  96                 of_node_put(chip->of_node);
  97  }
  98 +
  99 +static struct of_device_id gpio_export_ids[] = {
 100 +       { .compatible = "gpio-export" },
 101 +       { /* sentinel */ }
 102 +};
 103 +
 104 +static int __init of_gpio_export_probe(struct platform_device *pdev)
 105 +{
 106 +       struct device_node *np = pdev->dev.of_node;
 107 +       struct device_node *cnp;
 108 +       u32 val;
 109 +       int nb = 0;
 110 +
 111 +       for_each_child_of_node(np, cnp) {
 112 +               const char *name = NULL;
 113 +               int gpio;
 114 +               bool dmc;
 115 +               int max_gpio = 1;
 116 +               int i;
 117 +
 118 +               of_property_read_string(cnp, "gpio-export,name", &name);
 119 +
 120 +               if (!name)
 121 +                       max_gpio = of_gpio_count(cnp);
 122 +
 123 +               for (i = 0; i < max_gpio; i++) {
 124 +                       gpio = of_get_gpio(cnp, i);
 125 +                       if (devm_gpio_request(&pdev->dev, gpio, name ? name : of_node_full_name(np)))
 126 +                               continue;
 127 +
 128 +                       if (!of_property_read_u32(cnp, "gpio-export,output", &val))
 129 +                               gpio_direction_output(gpio, val);
 130 +                       else
 131 +                               gpio_direction_input(gpio);
 132 +
 133 +                       dmc = of_property_read_bool(np, "gpio-export,direction_may_change");
 134 +                       gpio_export_with_name(gpio, dmc, name);
 135 +                       nb++;
 136 +               }
 137 +       }
 138 +
 139 +       dev_info(&pdev->dev, "%d gpio(s) exported\n", nb);
 140 +
 141 +       return 0;
 142 +}
 143 +
 144 +static struct platform_driver gpio_export_driver = {
 145 +       .driver         = {
 146 +               .name           = "gpio-export",
 147 +               .owner  = THIS_MODULE,
 148 +               .of_match_table = of_match_ptr(gpio_export_ids),
 149 +       },
 150 +};
 151 +
 152 +static int __init of_gpio_export_init(void)
 153 +{
 154 +       return platform_driver_probe(&gpio_export_driver, of_gpio_export_probe);
 155 +}
 156 +device_initcall(of_gpio_export_init);
 157 --- a/drivers/gpio/gpiolib.c
 158 +++ b/drivers/gpio/gpiolib.c
 159 @@ -714,9 +714,10 @@ static struct class gpio_class = {
 160
 161
 162  /**
 163 - * gpio_export - export a GPIO through sysfs
 164 + * gpio_export_with_name - export a GPIO through sysfs
 165   * @gpio: gpio to make available, already requested
 166   * @direction_may_change: true if userspace may change gpio direction
 167 + * @name: gpio name
 168   * Context: arch_initcall or later
 169   *
 170   * When drivers want to make a GPIO accessible to userspace after they
 171 @@ -728,7 +729,7 @@ static struct class gpio_class = {
 172   *
 173   * Returns zero on success, else an error.
 174   */
 175 -int gpio_export(unsigned gpio, bool direction_may_change)
 176 +int gpio_export_with_name(unsigned gpio, bool direction_may_change, const char *name)
 177  {
 178         unsigned long           flags;
 179         struct gpio_desc        *desc;
 180 @@ -762,6 +763,8 @@ int gpio_export(unsigned gpio, bool dire
 181                 goto fail_unlock;
 182         }
 183
 184 +       if (name)
 185 +               ioname = name;
 186         if (!desc->chip->direction_input || !desc->chip->direction_output)
 187                 direction_may_change = false;
 188         spin_unlock_irqrestore(&gpio_lock, flags);
 189 @@ -804,7 +807,7 @@ fail_unlock:
 190         pr_debug("%s: gpio%d status %d\n", __func__, gpio, status);
 191         return status;
 192  }
 193 -EXPORT_SYMBOL_GPL(gpio_export);
 194 +EXPORT_SYMBOL_GPL(gpio_export_with_name);
 195
 196  static int match_export(struct device *dev, void *data)
 197  {
 198 --- a/include/asm-generic/gpio.h
 199 +++ b/include/asm-generic/gpio.h
 200 @@ -204,7 +204,8 @@ void devm_gpio_free(struct device *dev,
 201   * A sysfs interface can be exported by individual drivers if they want,
 202   * but more typically is configured entirely from userspace.
 203   */
 204 -extern int gpio_export(unsigned gpio, bool direction_may_change);
 205 +extern int gpio_export_with_name(unsigned gpio, bool direction_may_change,
 206 +                       const char *name);
 207  extern int gpio_export_link(struct device *dev, const char *name,
 208                         unsigned gpio);
 209  extern int gpio_sysfs_set_active_low(unsigned gpio, int value);
 210 @@ -249,7 +250,8 @@ struct device;
 211
 212  /* sysfs support is only available with gpiolib, where it's optional */
 213
 214 -static inline int gpio_export(unsigned gpio, bool direction_may_change)
 215 +static inline int gpio_export_with_name(unsigned gpio,
 216 +       bool direction_may_change, const char *name)
 217  {
 218         return -ENOSYS;
 219  }
 220 --- a/include/linux/gpio.h
 221 +++ b/include/linux/gpio.h
 222 @@ -189,7 +189,8 @@ static inline void gpio_set_value_cansle
 223         WARN_ON(1);
 224  }
 225
 226 -static inline int gpio_export(unsigned gpio, bool direction_may_change)
 227 +static inline int gpio_export_with_name(unsigned gpio,
 228 +       bool direction_may_change, const char *name)
 229  {
 230         /* GPIO can never have been requested or set as {in,out}put */
 231         WARN_ON(1);
 232 @@ -248,4 +249,24 @@ gpiochip_remove_pin_ranges(struct gpio_c
 233
 234  #endif /* ! CONFIG_GENERIC_GPIO */
 235
 236 +/**
 237 + * gpio_export - export a GPIO through sysfs
 238 + * @gpio: gpio to make available, already requested
 239 + * @direction_may_change: true if userspace may change gpio direction
 240 + * Context: arch_initcall or later
 241 + *
 242 + * When drivers want to make a GPIO accessible to userspace after they
 243 + * have requested it -- perhaps while debugging, or as part of their
 244 + * public interface -- they may use this routine.  If the GPIO can
 245 + * change direction (some can't) and the caller allows it, userspace
 246 + * will see "direction" sysfs attribute which may be used to change
 247 + * the gpio's direction.  A "value" attribute will always be provided.
 248 + *
 249 + * Returns zero on success, else an error.
 250 + */
 251 +static inline int gpio_export(unsigned gpio,bool direction_may_change)
 252 +{
 253 +       return gpio_export_with_name(gpio, direction_may_change, NULL);
 254 +}
 255 +
 256  #endif /* __LINUX_GPIO_H */