drivers/gpio/wm8994-gpio.c

   1 /*
   2  * wm8994-gpio.c  --  gpiolib support for Wolfson WM8994
   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/slab.h>
  17 #include <linux/module.h>
  18 #include <linux/gpio.h>
  19 #include <linux/mfd/core.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/seq_file.h>
  22
  23 #include <linux/mfd/wm8994/core.h>
  24 #include <linux/mfd/wm8994/pdata.h>
  25 #include <linux/mfd/wm8994/gpio.h>
  26 #include <linux/mfd/wm8994/registers.h>
  27
  28 struct wm8994_gpio {
  29         struct wm8994 *wm8994;
  30         struct gpio_chip gpio_chip;
  31 };
  32
  33 static inline struct wm8994_gpio *to_wm8994_gpio(struct gpio_chip *chip)
  34 {
  35         return container_of(chip, struct wm8994_gpio, gpio_chip);
  36 }
  37
  38 static int wm8994_gpio_direction_in(struct gpio_chip *chip, unsigned offset)
  39 {
  40         struct wm8994_gpio *wm8994_gpio = to_wm8994_gpio(chip);
  41         struct wm8994 *wm8994 = wm8994_gpio->wm8994;
  42
  43         return wm8994_set_bits(wm8994, WM8994_GPIO_1 + offset,
  44                                WM8994_GPN_DIR, WM8994_GPN_DIR);
  45 }
  46
  47 static int wm8994_gpio_get(struct gpio_chip *chip, unsigned offset)
  48 {
  49         struct wm8994_gpio *wm8994_gpio = to_wm8994_gpio(chip);
  50         struct wm8994 *wm8994 = wm8994_gpio->wm8994;
  51         int ret;
  52
  53         ret = wm8994_reg_read(wm8994, WM8994_GPIO_1 + offset);
  54         if (ret < 0)
  55                 return ret;
  56
  57         if (ret & WM8994_GPN_LVL)
  58                 return 1;
  59         else
  60                 return 0;
  61 }
  62
  63 static int wm8994_gpio_direction_out(struct gpio_chip *chip,
  64                                      unsigned offset, int value)
  65 {
  66         struct wm8994_gpio *wm8994_gpio = to_wm8994_gpio(chip);
  67         struct wm8994 *wm8994 = wm8994_gpio->wm8994;
  68
  69         return wm8994_set_bits(wm8994, WM8994_GPIO_1 + offset,
  70                                WM8994_GPN_DIR, 0);
  71 }
  72
  73 static void wm8994_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
  74 {
  75         struct wm8994_gpio *wm8994_gpio = to_wm8994_gpio(chip);
  76         struct wm8994 *wm8994 = wm8994_gpio->wm8994;
  77
  78         if (value)
  79                 value = WM8994_GPN_LVL;
  80
  81         wm8994_set_bits(wm8994, WM8994_GPIO_1 + offset, WM8994_GPN_LVL, value);
  82 }
  83
  84 #ifdef CONFIG_DEBUG_FS
  85 static void wm8994_gpio_dbg_show(struct seq_file *s, struct gpio_chip *chip)
  86 {
  87         struct wm8994_gpio *wm8994_gpio = to_wm8994_gpio(chip);
  88         struct wm8994 *wm8994 = wm8994_gpio->wm8994;
  89         int i;
  90
  91         for (i = 0; i < chip->ngpio; i++) {
  92                 int gpio = i + chip->base;
  93                 int reg;
  94                 const char *label;
  95
  96                 /* We report the GPIO even if it's not requested since
  97                  * we're also reporting things like alternate
  98                  * functions which apply even when the GPIO is not in
  99                  * use as a GPIO.
 100                  */
 101                 label = gpiochip_is_requested(chip, i);
 102                 if (!label)
 103                         label = "Unrequested";
 104
 105                 seq_printf(s, " gpio-%-3d (%-20.20s) ", gpio, label);
 106
 107                 reg = wm8994_reg_read(wm8994, WM8994_GPIO_1 + i);
 108                 if (reg < 0) {
 109                         dev_err(wm8994->dev,
 110                                 "GPIO control %d read failed: %d\n",
 111                                 gpio, reg);
 112                         seq_printf(s, "\n");
 113                         continue;
 114                 }
 115
 116                 /* No decode yet; note that GPIO2 is special */
 117                 seq_printf(s, "(%x)\n", reg);
 118         }
 119 }
 120 #else
 121 #define wm8994_gpio_dbg_show NULL
 122 #endif
 123
 124 static struct gpio_chip template_chip = {
 125         .label                  = "wm8994",
 126         .owner                  = THIS_MODULE,
 127         .direction_input        = wm8994_gpio_direction_in,
 128         .get                    = wm8994_gpio_get,
 129         .direction_output       = wm8994_gpio_direction_out,
 130         .set                    = wm8994_gpio_set,
 131         .dbg_show               = wm8994_gpio_dbg_show,
 132         .can_sleep              = 1,
 133 };
 134
 135 static int __devinit wm8994_gpio_probe(struct platform_device *pdev)
 136 {
 137         struct wm8994 *wm8994 = dev_get_drvdata(pdev->dev.parent);
 138         struct wm8994_pdata *pdata = wm8994->dev->platform_data;
 139         struct wm8994_gpio *wm8994_gpio;
 140         int ret;
 141
 142         wm8994_gpio = kzalloc(sizeof(*wm8994_gpio), GFP_KERNEL);
 143         if (wm8994_gpio == NULL)
 144                 return -ENOMEM;
 145
 146         wm8994_gpio->wm8994 = wm8994;
 147         wm8994_gpio->gpio_chip = template_chip;
 148         wm8994_gpio->gpio_chip.ngpio = WM8994_GPIO_MAX;
 149         wm8994_gpio->gpio_chip.dev = &pdev->dev;
 150         if (pdata && pdata->gpio_base)
 151                 wm8994_gpio->gpio_chip.base = pdata->gpio_base;
 152         else
 153                 wm8994_gpio->gpio_chip.base = -1;
 154
 155         ret = gpiochip_add(&wm8994_gpio->gpio_chip);
 156         if (ret < 0) {
 157                 dev_err(&pdev->dev, "Could not register gpiochip, %d\n",
 158                         ret);
 159                 goto err;
 160         }
 161
 162         platform_set_drvdata(pdev, wm8994_gpio);
 163
 164         return ret;
 165
 166 err:
 167         kfree(wm8994_gpio);
 168         return ret;
 169 }
 170
 171 static int __devexit wm8994_gpio_remove(struct platform_device *pdev)
 172 {
 173         struct wm8994_gpio *wm8994_gpio = platform_get_drvdata(pdev);
 174         int ret;
 175
 176         ret = gpiochip_remove(&wm8994_gpio->gpio_chip);
 177         if (ret == 0)
 178                 kfree(wm8994_gpio);
 179
 180         return ret;
 181 }
 182
 183 static struct platform_driver wm8994_gpio_driver = {
 184         .driver.name    = "wm8994-gpio",
 185         .driver.owner   = THIS_MODULE,
 186         .probe          = wm8994_gpio_probe,
 187         .remove         = __devexit_p(wm8994_gpio_remove),
 188 };
 189
 190 static int __init wm8994_gpio_init(void)
 191 {
 192         return platform_driver_register(&wm8994_gpio_driver);
 193 }
 194 subsys_initcall(wm8994_gpio_init);
 195
 196 static void __exit wm8994_gpio_exit(void)
 197 {
 198         platform_driver_unregister(&wm8994_gpio_driver);
 199 }
 200 module_exit(wm8994_gpio_exit);
 201
 202 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
 203 MODULE_DESCRIPTION("GPIO interface for WM8994");
 204 MODULE_LICENSE("GPL");
 205 MODULE_ALIAS("platform:wm8994-gpio");