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 void moxart_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
  52 {
  53         struct moxart_gpio_chip *gc = to_moxart_gpio(chip);
  54         void __iomem *ioaddr = gc->base + GPIO_DATA_OUT;
  55         u32 reg = readl(ioaddr);
  56
  57         if (value)
  58                 reg = reg | BIT(offset);
  59         else
  60                 reg = reg & ~BIT(offset);
  61
  62         writel(reg, ioaddr);
  63 }
  64
  65 static int moxart_gpio_get(struct gpio_chip *chip, unsigned offset)
  66 {
  67         struct moxart_gpio_chip *gc = to_moxart_gpio(chip);
  68         u32 ret = readl(gc->base + GPIO_PIN_DIRECTION);
  69
  70         if (ret & BIT(offset))
  71                 return !!(readl(gc->base + GPIO_DATA_OUT) & BIT(offset));
  72         else
  73                 return !!(readl(gc->base + GPIO_DATA_IN) & BIT(offset));
  74 }
  75
  76 static int moxart_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
  77 {
  78         struct moxart_gpio_chip *gc = to_moxart_gpio(chip);
  79         void __iomem *ioaddr = gc->base + GPIO_PIN_DIRECTION;
  80
  81         writel(readl(ioaddr) & ~BIT(offset), ioaddr);
  82         return 0;
  83 }
  84
  85 static int moxart_gpio_direction_output(struct gpio_chip *chip,
  86                                         unsigned offset, int value)
  87 {
  88         struct moxart_gpio_chip *gc = to_moxart_gpio(chip);
  89         void __iomem *ioaddr = gc->base + GPIO_PIN_DIRECTION;
  90
  91         moxart_gpio_set(chip, offset, value);
  92         writel(readl(ioaddr) | BIT(offset), ioaddr);
  93         return 0;
  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                 return -ENOMEM;
 118         mgc->gpio = moxart_template_chip;
 119
 120         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 121         mgc->base = devm_ioremap_resource(dev, res);
 122         if (IS_ERR(mgc->base))
 123                 return PTR_ERR(mgc->base);
 124
 125         mgc->gpio.dev = dev;
 126
 127         ret = gpiochip_add(&mgc->gpio);
 128         if (ret) {
 129                 dev_err(dev, "%s: gpiochip_add failed\n",
 130                         dev->of_node->full_name);
 131                 return ret;
 132         }
 133
 134         return 0;
 135 }
 136
 137 static const struct of_device_id moxart_gpio_match[] = {
 138         { .compatible = "moxa,moxart-gpio" },
 139         { }
 140 };
 141
 142 static struct platform_driver moxart_gpio_driver = {
 143         .driver = {
 144                 .name           = "moxart-gpio",
 145                 .of_match_table = moxart_gpio_match,
 146         },
 147         .probe  = moxart_gpio_probe,
 148 };
 149 module_platform_driver(moxart_gpio_driver);
 150
 151 MODULE_DESCRIPTION("MOXART GPIO chip driver");
 152 MODULE_LICENSE("GPL");
 153 MODULE_AUTHOR("Jonas Jensen <jonas.jensen@gmail.com>");