target/linux/mcs814x/files-3.14/drivers/gpio/gpio-mcs814x.c

   1 /*
   2  * Moschip MCS814x GPIO support
   3  *
   4  * Copyright (C) 2012, Florian Fainelli <florian@openwrt.org>
   5  *
   6  * Licensed under the GPLv2
   7  */
   8
   9 #include <linux/init.h>
  10 #include <linux/module.h>
  11 #include <linux/kernel.h>
  12 #include <linux/slab.h>
  13 #include <linux/platform_device.h>
  14 #include <linux/gpio.h>
  15 #include <linux/io.h>
  16 #include <linux/of.h>
  17 #include <linux/of_address.h>
  18
  19 struct mcs814x_gpio_chip {
  20         void __iomem *regs;
  21         struct gpio_chip chip;
  22 };
  23
  24 #define GPIO_PIN        0x00
  25 #define GPIO_DIR        0x04
  26
  27 #define to_mcs814x_gpio_chip(x) container_of(x, struct mcs814x_gpio_chip, chip)
  28
  29 static int mcs814x_gpio_get(struct gpio_chip *chip, unsigned offset)
  30 {
  31         struct mcs814x_gpio_chip *mcs814x = to_mcs814x_gpio_chip(chip);
  32
  33         return readl_relaxed(mcs814x->regs + GPIO_PIN) & (1 << offset);
  34 }
  35
  36 static void mcs814x_gpio_set(struct gpio_chip *chip,
  37                                 unsigned offset, int value)
  38 {
  39         struct mcs814x_gpio_chip *mcs814x = to_mcs814x_gpio_chip(chip);
  40         u32 mask;
  41
  42         mask = readl_relaxed(mcs814x->regs + GPIO_PIN);
  43         if (value)
  44                 mask |= (1 << offset);
  45         else
  46                 mask &= ~(1 << offset);
  47         writel_relaxed(mask, mcs814x->regs + GPIO_PIN);
  48 }
  49
  50 static int mcs814x_gpio_direction_output(struct gpio_chip *chip,
  51                                         unsigned offset, int value)
  52 {
  53         struct mcs814x_gpio_chip *mcs814x = to_mcs814x_gpio_chip(chip);
  54         u32 mask;
  55
  56         mask = readl_relaxed(mcs814x->regs + GPIO_DIR);
  57         mask &= ~(1 << offset);
  58         writel_relaxed(mask, mcs814x->regs + GPIO_DIR);
  59
  60         return 0;
  61 }
  62
  63 static int mcs814x_gpio_direction_input(struct gpio_chip *chip,
  64                                         unsigned offset)
  65 {
  66         struct mcs814x_gpio_chip *mcs814x = to_mcs814x_gpio_chip(chip);
  67         u32 mask;
  68
  69         mask = readl_relaxed(mcs814x->regs + GPIO_DIR);
  70         mask |= (1 << offset);
  71         writel_relaxed(mask, mcs814x->regs + GPIO_DIR);
  72
  73         return 0;
  74 }
  75
  76 static int mcs814x_gpio_probe(struct platform_device *pdev)
  77 {
  78         struct resource *res;
  79         struct mcs814x_gpio_chip *mcs814x_chip;
  80         int ret;
  81         const unsigned int *num_gpios;
  82
  83         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  84         if (!res)
  85                 return -ENODEV;
  86
  87         num_gpios = of_get_property(pdev->dev.of_node, "num-gpios", NULL);
  88         if (!num_gpios)
  89                 dev_err(&pdev->dev, "FIXME: no num-gpios property\n");
  90
  91         mcs814x_chip = kzalloc(sizeof(*mcs814x_chip), GFP_KERNEL);
  92         if (!mcs814x_chip)
  93                 return -ENOMEM;
  94
  95         mcs814x_chip->regs = devm_request_and_ioremap(&pdev->dev, res);
  96         if (!mcs814x_chip->regs) {
  97                 ret = -ENOMEM;
  98                 goto out;
  99         }
 100
 101         platform_set_drvdata(pdev, mcs814x_chip);
 102
 103 #ifdef CONFIG_OF_GPIO
 104         mcs814x_chip->chip.of_node = pdev->dev.of_node;
 105 #endif
 106
 107         mcs814x_chip->chip.label = pdev->name;
 108         mcs814x_chip->chip.get = mcs814x_gpio_get;
 109         mcs814x_chip->chip.set = mcs814x_gpio_set;
 110         mcs814x_chip->chip.direction_input = mcs814x_gpio_direction_input;
 111         mcs814x_chip->chip.direction_output = mcs814x_gpio_direction_output;
 112         mcs814x_chip->chip.ngpio = be32_to_cpup(num_gpios);
 113         /* we want dynamic base allocation */
 114         mcs814x_chip->chip.base = -1;
 115
 116         ret = gpiochip_add(&mcs814x_chip->chip);
 117         if (ret) {
 118                 dev_err(&pdev->dev, "failed to register gpiochip\n");
 119                 goto out;
 120         }
 121
 122         return 0;
 123
 124 out:
 125         platform_set_drvdata(pdev, NULL);
 126         kfree(mcs814x_chip);
 127         return ret;
 128 }
 129
 130 static struct of_device_id mcs814x_gpio_ids[] = {
 131         { .compatible = "moschip,mcs814x-gpio" },
 132         { /* sentinel */ },
 133 };
 134
 135 static struct platform_driver mcs814x_gpio_driver = {
 136         .driver = {
 137                 .name   = "mcs814x-gpio",
 138                 .owner  = THIS_MODULE,
 139                 .of_match_table = mcs814x_gpio_ids,
 140         },
 141         .probe  = mcs814x_gpio_probe,
 142 };
 143
 144 int __init mcs814x_gpio_init(void)
 145 {
 146         return platform_driver_register(&mcs814x_gpio_driver);
 147 }
 148 postcore_initcall(mcs814x_gpio_init);