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 static int wm8994_gpio_to_irq(struct gpio_chip *chip, unsigned offset)
  85 {
  86         struct wm8994_gpio *wm8994_gpio = to_wm8994_gpio(chip);
  87         struct wm8994 *wm8994 = wm8994_gpio->wm8994;
  88
  89         if (!wm8994->irq_base)
  90                 return -EINVAL;
  91
  92         return wm8994->irq_base + offset;
  93 }
  94
  95
  96 #ifdef CONFIG_DEBUG_FS
  97 static void wm8994_gpio_dbg_show(struct seq_file *s, struct gpio_chip *chip)
  98 {
  99         struct wm8994_gpio *wm8994_gpio = to_wm8994_gpio(chip);
 100         struct wm8994 *wm8994 = wm8994_gpio->wm8994;
 101         int i;
 102
 103         for (i = 0; i < chip->ngpio; i++) {
 104                 int gpio = i + chip->base;
 105                 int reg;
 106                 const char *label;
 107
 108                 /* We report the GPIO even if it's not requested since
 109                  * we're also reporting things like alternate
 110                  * functions which apply even when the GPIO is not in
 111                  * use as a GPIO.
 112                  */
 113                 label = gpiochip_is_requested(chip, i);
 114                 if (!label)
 115                         label = "Unrequested";
 116
 117                 seq_printf(s, " gpio-%-3d (%-20.20s) ", gpio, label);
 118
 119                 reg = wm8994_reg_read(wm8994, WM8994_GPIO_1 + i);
 120                 if (reg < 0) {
 121                         dev_err(wm8994->dev,
 122                                 "GPIO control %d read failed: %d\n",
 123                                 gpio, reg);
 124                         seq_printf(s, "\n");
 125                         continue;
 126                 }
 127
 128                 /* No decode yet; note that GPIO2 is special */
 129                 seq_printf(s, "(%x)\n", reg);
 130         }
 131 }
 132 #else
 133 #define wm8994_gpio_dbg_show NULL
 134 #endif
 135
 136 static struct gpio_chip template_chip = {
 137         .label                  = "wm8994",
 138         .owner                  = THIS_MODULE,
 139         .direction_input        = wm8994_gpio_direction_in,
 140         .get                    = wm8994_gpio_get,
 141         .direction_output       = wm8994_gpio_direction_out,
 142         .set                    = wm8994_gpio_set,
 143         .to_irq                 = wm8994_gpio_to_irq,
 144         .dbg_show               = wm8994_gpio_dbg_show,
 145         .can_sleep              = 1,
 146 };
 147
 148 static int __devinit wm8994_gpio_probe(struct platform_device *pdev)
 149 {
 150         struct wm8994 *wm8994 = dev_get_drvdata(pdev->dev.parent);
 151         struct wm8994_pdata *pdata = wm8994->dev->platform_data;
 152         struct wm8994_gpio *wm8994_gpio;
 153         int ret;
 154
 155         wm8994_gpio = kzalloc(sizeof(*wm8994_gpio), GFP_KERNEL);
 156         if (wm8994_gpio == NULL)
 157                 return -ENOMEM;
 158
 159         wm8994_gpio->wm8994 = wm8994;
 160         wm8994_gpio->gpio_chip = template_chip;
 161         wm8994_gpio->gpio_chip.ngpio = WM8994_GPIO_MAX;
 162         wm8994_gpio->gpio_chip.dev = &pdev->dev;
 163         if (pdata && pdata->gpio_base)
 164                 wm8994_gpio->gpio_chip.base = pdata->gpio_base;
 165         else
 166                 wm8994_gpio->gpio_chip.base = -1;
 167
 168         ret = gpiochip_add(&wm8994_gpio->gpio_chip);
 169         if (ret < 0) {
 170                 dev_err(&pdev->dev, "Could not register gpiochip, %d\n",
 171                         ret);
 172                 goto err;
 173         }
 174
 175         platform_set_drvdata(pdev, wm8994_gpio);
 176
 177         return ret;
 178
 179 err:
 180         kfree(wm8994_gpio);
 181         return ret;
 182 }
 183
 184 static int __devexit wm8994_gpio_remove(struct platform_device *pdev)
 185 {
 186         struct wm8994_gpio *wm8994_gpio = platform_get_drvdata(pdev);
 187         int ret;
 188
 189         ret = gpiochip_remove(&wm8994_gpio->gpio_chip);
 190         if (ret == 0)
 191                 kfree(wm8994_gpio);
 192
 193         return ret;
 194 }
 195
 196 static struct platform_driver wm8994_gpio_driver = {
 197         .driver.name    = "wm8994-gpio",
 198         .driver.owner   = THIS_MODULE,
 199         .probe          = wm8994_gpio_probe,
 200         .remove         = __devexit_p(wm8994_gpio_remove),
 201 };
 202
 203 static int __init wm8994_gpio_init(void)
 204 {
 205         return platform_driver_register(&wm8994_gpio_driver);
 206 }
 207 subsys_initcall(wm8994_gpio_init);
 208
 209 static void __exit wm8994_gpio_exit(void)
 210 {
 211         platform_driver_unregister(&wm8994_gpio_driver);
 212 }
 213 module_exit(wm8994_gpio_exit);
 214
 215 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
 216 MODULE_DESCRIPTION("GPIO interface for WM8994");
 217 MODULE_LICENSE("GPL");
 218 MODULE_ALIAS("platform:wm8994-gpio");