drivers/gpio/gpio-moxart.c

   1 /*
   2  * MOXA ART SoCs GPIO driver.
   3  *
   4  * Copyright (C) 2013 Jonas Jensen
   5  *
   6  * Jonas Jensen <jonas.jensen@gmail.com>
   7  *
   8  * This file is licensed under the terms of the GNU General Public
   9  * License version 2.  This program is licensed "as is" without any
  10  * warranty of any kind, whether express or implied.
  11  */
  12
  13 #include <linux/err.h>
  14 #include <linux/init.h>
  15 #include <linux/irq.h>
  16 #include <linux/io.h>
  17 #include <linux/gpio.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/module.h>
  20 #include <linux/of_address.h>
  21 #include <linux/of_gpio.h>
  22 #include <linux/pinctrl/consumer.h>
  23 #include <linux/delay.h>
  24 #include <linux/timer.h>
  25 #include <linux/bitops.h>
  26
  27 #define GPIO_DATA_OUT           0x00
  28 #define GPIO_DATA_IN            0x04
  29 #define GPIO_PIN_DIRECTION      0x08
  30
  31 struct moxart_gpio_chip {
  32         struct gpio_chip gpio;
  33         void __iomem *base;
  34 };
  35
  36 static inline struct moxart_gpio_chip *to_moxart_gpio(struct gpio_chip *chip)
  37 {
  38         return container_of(chip, struct moxart_gpio_chip, gpio);
  39 }
  40
  41 static int moxart_gpio_request(struct gpio_chip *chip, unsigned offset)
  42 {
  43         return pinctrl_request_gpio(offset);
  44 }
  45
  46 static void moxart_gpio_free(struct gpio_chip *chip, unsigned offset)
  47 {
  48         pinctrl_free_gpio(offset);
  49 }
  50
  51 static int moxart_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
  52 {
  53         struct moxart_gpio_chip *gc = to_moxart_gpio(chip);
  54         void __iomem *ioaddr = gc->base + GPIO_PIN_DIRECTION;
  55
  56         writel(readl(ioaddr) & ~BIT(offset), ioaddr);
  57         return 0;
  58 }
  59
  60 static int moxart_gpio_direction_output(struct gpio_chip *chip,
  61                                         unsigned offset, int value)
  62 {
  63         struct moxart_gpio_chip *gc = to_moxart_gpio(chip);
  64         void __iomem *ioaddr = gc->base + GPIO_PIN_DIRECTION;
  65
  66         writel(readl(ioaddr) | BIT(offset), ioaddr);
  67         return 0;
  68 }
  69
  70 static void moxart_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
  71 {
  72         struct moxart_gpio_chip *gc = to_moxart_gpio(chip);
  73         void __iomem *ioaddr = gc->base + GPIO_DATA_OUT;
  74         u32 reg = readl(ioaddr);
  75
  76         if (value)
  77                 reg = reg | BIT(offset);
  78         else
  79                 reg = reg & ~BIT(offset);
  80
  81
  82         writel(reg, ioaddr);
  83 }
  84
  85 static int moxart_gpio_get(struct gpio_chip *chip, unsigned offset)
  86 {
  87         struct moxart_gpio_chip *gc = to_moxart_gpio(chip);
  88         u32 ret = readl(gc->base + GPIO_PIN_DIRECTION);
  89
  90         if (ret & BIT(offset))
  91                 return !!(readl(gc->base + GPIO_DATA_OUT) & BIT(offset));
  92         else
  93                 return !!(readl(gc->base + GPIO_DATA_IN) & BIT(offset));
  94 }
  95
  96 static struct gpio_chip moxart_template_chip = {
  97         .label                  = "moxart-gpio",
  98         .request                = moxart_gpio_request,
  99         .free                   = moxart_gpio_free,
 100         .direction_input        = moxart_gpio_direction_input,
 101         .direction_output       = moxart_gpio_direction_output,
 102         .set                    = moxart_gpio_set,
 103         .get                    = moxart_gpio_get,
 104         .ngpio                  = 32,
 105         .owner                  = THIS_MODULE,
 106 };
 107
 108 static int moxart_gpio_probe(struct platform_device *pdev)
 109 {
 110         struct device *dev = &pdev->dev;
 111         struct resource *res;
 112         struct moxart_gpio_chip *mgc;
 113         int ret;
 114
 115         mgc = devm_kzalloc(dev, sizeof(*mgc), GFP_KERNEL);
 116         if (!mgc) {
 117                 dev_err(dev, "can't allocate GPIO chip container\n");
 118                 return -ENOMEM;
 119         }
 120         mgc->gpio = moxart_template_chip;
 121
 122         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 123         mgc->base = devm_ioremap_resource(dev, res);
 124         if (IS_ERR(mgc->base))
 125                 return PTR_ERR(mgc->base);
 126
 127         mgc->gpio.dev = dev;
 128
 129         ret = gpiochip_add(&mgc->gpio);
 130         if (ret) {
 131                 dev_err(dev, "%s: gpiochip_add failed\n",
 132                         dev->of_node->full_name);
 133                 return ret;
 134         }
 135
 136         return 0;
 137 }
 138
 139 static const struct of_device_id moxart_gpio_match[] = {
 140         { .compatible = "moxa,moxart-gpio" },
 141         { }
 142 };
 143
 144 static struct platform_driver moxart_gpio_driver = {
 145         .driver = {
 146                 .name           = "moxart-gpio",
 147                 .owner          = THIS_MODULE,
 148                 .of_match_table = moxart_gpio_match,
 149         },
 150         .probe  = moxart_gpio_probe,
 151 };
 152 module_platform_driver(moxart_gpio_driver);
 153
 154 MODULE_DESCRIPTION("MOXART GPIO chip driver");
 155 MODULE_LICENSE("GPL");
 156 MODULE_AUTHOR("Jonas Jensen <jonas.jensen@gmail.com>");