drivers/gpio/wm831x-gpio.c

   1 /*
   2  * wm831x-gpio.c  --  gpiolib support for Wolfson WM831x PMICs
   3  *
   4  * Copyright 2009 Wolfson Microelectronics PLC.
   5  *
   6  * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
   7  *
   8  *  This program is free software; you can redistribute  it and/or modify it
   9  *  under  the terms of  the GNU General  Public License as published by the
  10  *  Free Software Foundation;  either version 2 of the  License, or (at your
  11  *  option) any later version.
  12  *
  13  */
  14
  15 #include <linux/kernel.h>
  16 #include <linux/module.h>
  17 #include <linux/gpio.h>
  18 #include <linux/mfd/core.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/seq_file.h>
  21
  22 #include <linux/mfd/wm831x/core.h>
  23 #include <linux/mfd/wm831x/pdata.h>
  24 #include <linux/mfd/wm831x/gpio.h>
  25
  26 #define WM831X_GPIO_MAX 16
  27
  28 struct wm831x_gpio {
  29         struct wm831x *wm831x;
  30         struct gpio_chip gpio_chip;
  31 };
  32
  33 static inline struct wm831x_gpio *to_wm831x_gpio(struct gpio_chip *chip)
  34 {
  35         return container_of(chip, struct wm831x_gpio, gpio_chip);
  36 }
  37
  38 static int wm831x_gpio_direction_in(struct gpio_chip *chip, unsigned offset)
  39 {
  40         struct wm831x_gpio *wm831x_gpio = to_wm831x_gpio(chip);
  41         struct wm831x *wm831x = wm831x_gpio->wm831x;
  42
  43         return wm831x_set_bits(wm831x, WM831X_GPIO1_CONTROL + offset,
  44                                WM831X_GPN_DIR | WM831X_GPN_TRI,
  45                                WM831X_GPN_DIR);
  46 }
  47
  48 static int wm831x_gpio_get(struct gpio_chip *chip, unsigned offset)
  49 {
  50         struct wm831x_gpio *wm831x_gpio = to_wm831x_gpio(chip);
  51         struct wm831x *wm831x = wm831x_gpio->wm831x;
  52         int ret;
  53
  54         ret = wm831x_reg_read(wm831x, WM831X_GPIO_LEVEL);
  55         if (ret < 0)
  56                 return ret;
  57
  58         if (ret & 1 << offset)
  59                 return 1;
  60         else
  61                 return 0;
  62 }
  63
  64 static void wm831x_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
  65 {
  66         struct wm831x_gpio *wm831x_gpio = to_wm831x_gpio(chip);
  67         struct wm831x *wm831x = wm831x_gpio->wm831x;
  68
  69         wm831x_set_bits(wm831x, WM831X_GPIO_LEVEL, 1 << offset,
  70                         value << offset);
  71 }
  72
  73 static int wm831x_gpio_direction_out(struct gpio_chip *chip,
  74                                      unsigned offset, int value)
  75 {
  76         struct wm831x_gpio *wm831x_gpio = to_wm831x_gpio(chip);
  77         struct wm831x *wm831x = wm831x_gpio->wm831x;
  78         int ret;
  79
  80         ret = wm831x_set_bits(wm831x, WM831X_GPIO1_CONTROL + offset,
  81                               WM831X_GPN_DIR | WM831X_GPN_TRI, 0);
  82         if (ret < 0)
  83                 return ret;
  84
  85         /* Can only set GPIO state once it's in output mode */
  86         wm831x_gpio_set(chip, offset, value);
  87
  88         return 0;
  89 }
  90
  91 #ifdef CONFIG_DEBUG_FS
  92 static void wm831x_gpio_dbg_show(struct seq_file *s, struct gpio_chip *chip)
  93 {
  94         struct wm831x_gpio *wm831x_gpio = to_wm831x_gpio(chip);
  95         struct wm831x *wm831x = wm831x_gpio->wm831x;
  96         int i;
  97
  98         for (i = 0; i < chip->ngpio; i++) {
  99                 int gpio = i + chip->base;
 100                 int reg;
 101                 const char *label, *pull, *powerdomain;
 102
 103                 /* We report the GPIO even if it's not requested since
 104                  * we're also reporting things like alternate
 105                  * functions which apply even when the GPIO is not in
 106                  * use as a GPIO.
 107                  */
 108                 label = gpiochip_is_requested(chip, i);
 109                 if (!label)
 110                         label = "Unrequested";
 111
 112                 seq_printf(s, " gpio-%-3d (%-20.20s) ", gpio, label);
 113
 114                 reg = wm831x_reg_read(wm831x, WM831X_GPIO1_CONTROL + i);
 115                 if (reg < 0) {
 116                         dev_err(wm831x->dev,
 117                                 "GPIO control %d read failed: %d\n",
 118                                 gpio, reg);
 119                         seq_printf(s, "\n");
 120                         continue;
 121                 }
 122
 123                 switch (reg & WM831X_GPN_PULL_MASK) {
 124                 case WM831X_GPIO_PULL_NONE:
 125                         pull = "nopull";
 126                         break;
 127                 case WM831X_GPIO_PULL_DOWN:
 128                         pull = "pulldown";
 129                         break;
 130                 case WM831X_GPIO_PULL_UP:
 131                         pull = "pullup";
 132                 default:
 133                         pull = "INVALID PULL";
 134                         break;
 135                 }
 136
 137                 switch (i + 1) {
 138                 case 1 ... 3:
 139                 case 7 ... 9:
 140                         if (reg & WM831X_GPN_PWR_DOM)
 141                                 powerdomain = "VPMIC";
 142                         else
 143                                 powerdomain = "DBVDD";
 144                         break;
 145
 146                 case 4 ... 6:
 147                 case 10 ... 12:
 148                         if (reg & WM831X_GPN_PWR_DOM)
 149                                 powerdomain = "SYSVDD";
 150                         else
 151                                 powerdomain = "DBVDD";
 152                         break;
 153
 154                 case 13 ... 16:
 155                         powerdomain = "TPVDD";
 156                         break;
 157
 158                 default:
 159                         BUG();
 160                         break;
 161                 }
 162
 163                 seq_printf(s, " %s %s %s %s%s\n"
 164                            "                                  %s%s (0x%4x)\n",
 165                            reg & WM831X_GPN_DIR ? "in" : "out",
 166                            wm831x_gpio_get(chip, i) ? "high" : "low",
 167                            pull,
 168                            powerdomain,
 169                            reg & WM831X_GPN_POL ? " inverted" : "",
 170                            reg & WM831X_GPN_OD ? "open-drain" : "CMOS",
 171                            reg & WM831X_GPN_TRI ? " tristated" : "",
 172                            reg);
 173         }
 174 }
 175 #else
 176 #define wm831x_gpio_dbg_show NULL
 177 #endif
 178
 179 static struct gpio_chip template_chip = {
 180         .label                  = "wm831x",
 181         .owner                  = THIS_MODULE,
 182         .direction_input        = wm831x_gpio_direction_in,
 183         .get                    = wm831x_gpio_get,
 184         .direction_output       = wm831x_gpio_direction_out,
 185         .set                    = wm831x_gpio_set,
 186         .dbg_show               = wm831x_gpio_dbg_show,
 187         .can_sleep              = 1,
 188 };
 189
 190 static int __devinit wm831x_gpio_probe(struct platform_device *pdev)
 191 {
 192         struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
 193         struct wm831x_pdata *pdata = wm831x->dev->platform_data;
 194         struct wm831x_gpio *wm831x_gpio;
 195         int ret;
 196
 197         wm831x_gpio = kzalloc(sizeof(*wm831x_gpio), GFP_KERNEL);
 198         if (wm831x_gpio == NULL)
 199                 return -ENOMEM;
 200
 201         wm831x_gpio->wm831x = wm831x;
 202         wm831x_gpio->gpio_chip = template_chip;
 203         wm831x_gpio->gpio_chip.ngpio = WM831X_GPIO_MAX;
 204         wm831x_gpio->gpio_chip.dev = &pdev->dev;
 205         if (pdata && pdata->gpio_base)
 206                 wm831x_gpio->gpio_chip.base = pdata->gpio_base;
 207         else
 208                 wm831x_gpio->gpio_chip.base = -1;
 209
 210         ret = gpiochip_add(&wm831x_gpio->gpio_chip);
 211         if (ret < 0) {
 212                 dev_err(&pdev->dev, "Could not register gpiochip, %d\n",
 213                         ret);
 214                 goto err;
 215         }
 216
 217         platform_set_drvdata(pdev, wm831x_gpio);
 218
 219         return ret;
 220
 221 err:
 222         kfree(wm831x_gpio);
 223         return ret;
 224 }
 225
 226 static int __devexit wm831x_gpio_remove(struct platform_device *pdev)
 227 {
 228         struct wm831x_gpio *wm831x_gpio = platform_get_drvdata(pdev);
 229         int ret;
 230
 231         ret = gpiochip_remove(&wm831x_gpio->gpio_chip);
 232         if (ret == 0)
 233                 kfree(wm831x_gpio);
 234
 235         return ret;
 236 }
 237
 238 static struct platform_driver wm831x_gpio_driver = {
 239         .driver.name    = "wm831x-gpio",
 240         .driver.owner   = THIS_MODULE,
 241         .probe          = wm831x_gpio_probe,
 242         .remove         = __devexit_p(wm831x_gpio_remove),
 243 };
 244
 245 static int __init wm831x_gpio_init(void)
 246 {
 247         return platform_driver_register(&wm831x_gpio_driver);
 248 }
 249 subsys_initcall(wm831x_gpio_init);
 250
 251 static void __exit wm831x_gpio_exit(void)
 252 {
 253         platform_driver_unregister(&wm831x_gpio_driver);
 254 }
 255 module_exit(wm831x_gpio_exit);
 256
 257 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
 258 MODULE_DESCRIPTION("GPIO interface for WM831x PMICs");
 259 MODULE_LICENSE("GPL");
 260 MODULE_ALIAS("platform:wm831x-gpio");