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