target/linux/ramips/patches-3.10/0200-owrt-GPIO-add-gpio_export_with_name.patch

   1 From 8f3ed1fffa35d18c2b20ebb866c71a22cc0589ff Mon Sep 17 00:00:00 2001
   2 From: John Crispin <blogic@openwrt.org>
   3 Date: Sun, 23 Jun 2013 00:16:22 +0200
   4 Subject: [PATCH 29/33] 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                       |   68 +++++++++++++++++++++++
  12  drivers/gpio/gpiolib.c                          |   24 +++++---
  13  include/asm-generic/gpio.h                      |    6 +-
  14  include/linux/gpio.h                            |   26 ++++++++-
  15  5 files changed, 172 insertions(+), 12 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 @@ -242,3 +244,69 @@ 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 +                       unsigned flags = 0;
 125 +                       enum of_gpio_flags of_flags;
 126 +
 127 +                       gpio = of_get_gpio_flags(cnp, i, &of_flags);
 128 +
 129 +                       if (of_flags == OF_GPIO_ACTIVE_LOW)
 130 +                               flags |= GPIOF_ACTIVE_LOW;
 131 +
 132 +                       if (!of_property_read_u32(cnp, "gpio-export,output", &val))
 133 +                               flags |= val ? GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW;
 134 +                       else
 135 +                               flags |= GPIOF_IN;
 136 +
 137 +                       if (devm_gpio_request_one(&pdev->dev, gpio, flags, name ? name : of_node_full_name(np)))
 138 +                               continue;
 139 +
 140 +                       dmc = of_property_read_bool(cnp, "gpio-export,direction_may_change");
 141 +                       gpio_export_with_name(gpio, dmc, name);
 142 +                       nb++;
 143 +               }
 144 +       }
 145 +
 146 +       dev_info(&pdev->dev, "%d gpio(s) exported\n", nb);
 147 +
 148 +       return 0;
 149 +}
 150 +
 151 +static struct platform_driver gpio_export_driver = {
 152 +       .driver         = {
 153 +               .name           = "gpio-export",
 154 +               .owner  = THIS_MODULE,
 155 +               .of_match_table = of_match_ptr(gpio_export_ids),
 156 +       },
 157 +};
 158 +
 159 +static int __init of_gpio_export_init(void)
 160 +{
 161 +       return platform_driver_probe(&gpio_export_driver, of_gpio_export_probe);
 162 +}
 163 +device_initcall(of_gpio_export_init);
 164 --- a/drivers/gpio/gpiolib.c
 165 +++ b/drivers/gpio/gpiolib.c
 166 @@ -96,7 +96,7 @@ static int gpiod_get_value(const struct
 167  static void gpiod_set_value(struct gpio_desc *desc, int value);
 168  static int gpiod_cansleep(const struct gpio_desc *desc);
 169  static int gpiod_to_irq(const struct gpio_desc *desc);
 170 -static int gpiod_export(struct gpio_desc *desc, bool direction_may_change);
 171 +static int gpiod_export(struct gpio_desc *desc, bool direction_may_change, const char *name);
 172  static int gpiod_export_link(struct device *dev, const char *name,
 173                              struct gpio_desc *desc);
 174  static int gpiod_sysfs_set_active_low(struct gpio_desc *desc, int value);
 175 @@ -674,7 +674,7 @@ static ssize_t export_store(struct class
 176                         status = -ENODEV;
 177                 goto done;
 178         }
 179 -       status = gpiod_export(desc, true);
 180 +       status = gpiod_export(desc, true, NULL);
 181         if (status < 0)
 182                 gpiod_free(desc);
 183         else
 184 @@ -736,9 +736,10 @@ static struct class gpio_class = {
 185
 186
 187  /**
 188 - * gpio_export - export a GPIO through sysfs
 189 + * gpio_export_with_name - export a GPIO through sysfs
 190   * @gpio: gpio to make available, already requested
 191   * @direction_may_change: true if userspace may change gpio direction
 192 + * @name: gpio name
 193   * Context: arch_initcall or later
 194   *
 195   * When drivers want to make a GPIO accessible to userspace after they
 196 @@ -750,7 +751,7 @@ static struct class gpio_class = {
 197   *
 198   * Returns zero on success, else an error.
 199   */
 200 -static int gpiod_export(struct gpio_desc *desc, bool direction_may_change)
 201 +static int gpiod_export(struct gpio_desc *desc, bool direction_may_change, const char *name)
 202  {
 203         unsigned long           flags;
 204         int                     status;
 205 @@ -783,6 +784,8 @@ static int gpiod_export(struct gpio_desc
 206                 goto fail_unlock;
 207         }
 208
 209 +       if (name)
 210 +               ioname = name;
 211         if (!desc->chip->direction_input || !desc->chip->direction_output)
 212                 direction_may_change = false;
 213         spin_unlock_irqrestore(&gpio_lock, flags);
 214 @@ -829,11 +832,11 @@ fail_unlock:
 215         return status;
 216  }
 217
 218 -int gpio_export(unsigned gpio, bool direction_may_change)
 219 +int gpio_export_with_name(unsigned gpio, bool direction_may_change, const char *name)
 220  {
 221 -       return gpiod_export(gpio_to_desc(gpio), direction_may_change);
 222 +       return gpiod_export(gpio_to_desc(gpio), direction_may_change, name);
 223  }
 224 -EXPORT_SYMBOL_GPL(gpio_export);
 225 +EXPORT_SYMBOL_GPL(gpio_export_with_name);
 226
 227  static int match_export(struct device *dev, const void *data)
 228  {
 229 @@ -1092,7 +1095,7 @@ static inline void gpiochip_unexport(str
 230  }
 231
 232  static inline int gpiod_export(struct gpio_desc *desc,
 233 -                              bool direction_may_change)
 234 +                              bool direction_may_change, const char *name)
 235  {
 236         return -ENOSYS;
 237  }
 238 @@ -1521,6 +1524,9 @@ int gpio_request_one(unsigned gpio, unsi
 239         if (flags & GPIOF_OPEN_SOURCE)
 240                 set_bit(FLAG_OPEN_SOURCE, &desc->flags);
 241
 242 +       if (flags & GPIOF_ACTIVE_LOW)
 243 +               set_bit(FLAG_ACTIVE_LOW, &gpio_desc[gpio].flags);
 244 +
 245         if (flags & GPIOF_DIR_IN)
 246                 err = gpiod_direction_input(desc);
 247         else
 248 @@ -1531,7 +1537,7 @@ int gpio_request_one(unsigned gpio, unsi
 249                 goto free_gpio;
 250
 251         if (flags & GPIOF_EXPORT) {
 252 -               err = gpiod_export(desc, flags & GPIOF_EXPORT_CHANGEABLE);
 253 +               err = gpiod_export(desc, flags & GPIOF_EXPORT_CHANGEABLE, NULL);
 254                 if (err)
 255                         goto free_gpio;
 256         }
 257 --- a/include/asm-generic/gpio.h
 258 +++ b/include/asm-generic/gpio.h
 259 @@ -202,7 +202,8 @@ extern void gpio_free_array(const struct
 260   * A sysfs interface can be exported by individual drivers if they want,
 261   * but more typically is configured entirely from userspace.
 262   */
 263 -extern int gpio_export(unsigned gpio, bool direction_may_change);
 264 +extern int gpio_export_with_name(unsigned gpio, bool direction_may_change,
 265 +                       const char *name);
 266  extern int gpio_export_link(struct device *dev, const char *name,
 267                         unsigned gpio);
 268  extern int gpio_sysfs_set_active_low(unsigned gpio, int value);
 269 @@ -284,7 +285,8 @@ struct device;
 270
 271  /* sysfs support is only available with gpiolib, where it's optional */
 272
 273 -static inline int gpio_export(unsigned gpio, bool direction_may_change)
 274 +static inline int gpio_export_with_name(unsigned gpio,
 275 +       bool direction_may_change, const char *name)
 276  {
 277         return -ENOSYS;
 278  }
 279 --- a/include/linux/gpio.h
 280 +++ b/include/linux/gpio.h
 281 @@ -27,6 +27,9 @@
 282  #define GPIOF_EXPORT_DIR_FIXED (GPIOF_EXPORT)
 283  #define GPIOF_EXPORT_DIR_CHANGEABLE (GPIOF_EXPORT | GPIOF_EXPORT_CHANGEABLE)
 284
 285 +#define GPIOF_ACTIVE_LOW       (1 << 6)
 286 +
 287 +
 288  /**
 289   * struct gpio - a structure describing a GPIO with configuration
 290   * @gpio:      the GPIO number
 291 @@ -169,7 +172,8 @@ static inline void gpio_set_value_cansle
 292         WARN_ON(1);
 293  }
 294
 295 -static inline int gpio_export(unsigned gpio, bool direction_may_change)
 296 +static inline int gpio_export_with_name(unsigned gpio,
 297 +       bool direction_may_change, const char *name)
 298  {
 299         /* GPIO can never have been requested or set as {in,out}put */
 300         WARN_ON(1);
 301 @@ -236,4 +240,24 @@ int devm_gpio_request_one(struct device
 302                           unsigned long flags, const char *label);
 303  void devm_gpio_free(struct device *dev, unsigned int gpio);
 304
 305 +/**
 306 + * gpio_export - export a GPIO through sysfs
 307 + * @gpio: gpio to make available, already requested
 308 + * @direction_may_change: true if userspace may change gpio direction
 309 + * Context: arch_initcall or later
 310 + *
 311 + * When drivers want to make a GPIO accessible to userspace after they
 312 + * have requested it -- perhaps while debugging, or as part of their
 313 + * public interface -- they may use this routine.  If the GPIO can
 314 + * change direction (some can't) and the caller allows it, userspace
 315 + * will see "direction" sysfs attribute which may be used to change
 316 + * the gpio's direction.  A "value" attribute will always be provided.
 317 + *
 318 + * Returns zero on success, else an error.
 319 + */
 320 +static inline int gpio_export(unsigned gpio,bool direction_may_change)
 321 +{
 322 +       return gpio_export_with_name(gpio, direction_may_change, NULL);
 323 +}
 324 +
 325  #endif /* __LINUX_GPIO_H */