drivers/gpio/gpio-ath79.c

   1 /*
   2  *  Atheros AR71XX/AR724X/AR913X GPIO API support
   3  *
   4  *  Copyright (C) 2010-2011 Jaiganesh Narayanan <jnarayanan@atheros.com>
   5  *  Copyright (C) 2008-2011 Gabor Juhos <juhosg@openwrt.org>
   6  *  Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
   7  *
   8  *  Parts of this file are based on Atheros' 2.6.15/2.6.31 BSP
   9  *
  10  *  This program is free software; you can redistribute it and/or modify it
  11  *  under the terms of the GNU General Public License version 2 as published
  12  *  by the Free Software Foundation.
  13  */
  14
  15 #include <linux/gpio/driver.h>
  16 #include <linux/platform_data/gpio-ath79.h>
  17 #include <linux/of_device.h>
  18
  19 #include <asm/mach-ath79/ar71xx_regs.h>
  20
  21 struct ath79_gpio_ctrl {
  22         struct gpio_chip chip;
  23         void __iomem *base;
  24         spinlock_t lock;
  25 };
  26
  27 #define to_ath79_gpio_ctrl(c) container_of(c, struct ath79_gpio_ctrl, chip)
  28
  29 static void ath79_gpio_set_value(struct gpio_chip *chip,
  30                                 unsigned gpio, int value)
  31 {
  32         struct ath79_gpio_ctrl *ctrl = to_ath79_gpio_ctrl(chip);
  33
  34         if (value)
  35                 __raw_writel(BIT(gpio), ctrl->base + AR71XX_GPIO_REG_SET);
  36         else
  37                 __raw_writel(BIT(gpio), ctrl->base + AR71XX_GPIO_REG_CLEAR);
  38 }
  39
  40 static int ath79_gpio_get_value(struct gpio_chip *chip, unsigned gpio)
  41 {
  42         struct ath79_gpio_ctrl *ctrl = to_ath79_gpio_ctrl(chip);
  43
  44         return (__raw_readl(ctrl->base + AR71XX_GPIO_REG_IN) >> gpio) & 1;
  45 }
  46
  47 static int ath79_gpio_direction_input(struct gpio_chip *chip,
  48                                        unsigned offset)
  49 {
  50         struct ath79_gpio_ctrl *ctrl = to_ath79_gpio_ctrl(chip);
  51         unsigned long flags;
  52
  53         spin_lock_irqsave(&ctrl->lock, flags);
  54
  55         __raw_writel(
  56                 __raw_readl(ctrl->base + AR71XX_GPIO_REG_OE) & ~BIT(offset),
  57                 ctrl->base + AR71XX_GPIO_REG_OE);
  58
  59         spin_unlock_irqrestore(&ctrl->lock, flags);
  60
  61         return 0;
  62 }
  63
  64 static int ath79_gpio_direction_output(struct gpio_chip *chip,
  65                                         unsigned offset, int value)
  66 {
  67         struct ath79_gpio_ctrl *ctrl = to_ath79_gpio_ctrl(chip);
  68         unsigned long flags;
  69
  70         spin_lock_irqsave(&ctrl->lock, flags);
  71
  72         if (value)
  73                 __raw_writel(BIT(offset), ctrl->base + AR71XX_GPIO_REG_SET);
  74         else
  75                 __raw_writel(BIT(offset), ctrl->base + AR71XX_GPIO_REG_CLEAR);
  76
  77         __raw_writel(
  78                 __raw_readl(ctrl->base + AR71XX_GPIO_REG_OE) | BIT(offset),
  79                 ctrl->base + AR71XX_GPIO_REG_OE);
  80
  81         spin_unlock_irqrestore(&ctrl->lock, flags);
  82
  83         return 0;
  84 }
  85
  86 static int ar934x_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
  87 {
  88         struct ath79_gpio_ctrl *ctrl = to_ath79_gpio_ctrl(chip);
  89         unsigned long flags;
  90
  91         spin_lock_irqsave(&ctrl->lock, flags);
  92
  93         __raw_writel(
  94                 __raw_readl(ctrl->base + AR71XX_GPIO_REG_OE) | BIT(offset),
  95                 ctrl->base + AR71XX_GPIO_REG_OE);
  96
  97         spin_unlock_irqrestore(&ctrl->lock, flags);
  98
  99         return 0;
 100 }
 101
 102 static int ar934x_gpio_direction_output(struct gpio_chip *chip, unsigned offset,
 103                                         int value)
 104 {
 105         struct ath79_gpio_ctrl *ctrl = to_ath79_gpio_ctrl(chip);
 106         unsigned long flags;
 107
 108         spin_lock_irqsave(&ctrl->lock, flags);
 109
 110         if (value)
 111                 __raw_writel(BIT(offset), ctrl->base + AR71XX_GPIO_REG_SET);
 112         else
 113                 __raw_writel(BIT(offset), ctrl->base + AR71XX_GPIO_REG_CLEAR);
 114
 115         __raw_writel(
 116                 __raw_readl(ctrl->base + AR71XX_GPIO_REG_OE) & BIT(offset),
 117                 ctrl->base + AR71XX_GPIO_REG_OE);
 118
 119         spin_unlock_irqrestore(&ctrl->lock, flags);
 120
 121         return 0;
 122 }
 123
 124 static const struct gpio_chip ath79_gpio_chip = {
 125         .label                  = "ath79",
 126         .get                    = ath79_gpio_get_value,
 127         .set                    = ath79_gpio_set_value,
 128         .direction_input        = ath79_gpio_direction_input,
 129         .direction_output       = ath79_gpio_direction_output,
 130         .base                   = 0,
 131 };
 132
 133 static const struct of_device_id ath79_gpio_of_match[] = {
 134         { .compatible = "qca,ar7100-gpio" },
 135         { .compatible = "qca,ar9340-gpio" },
 136         {},
 137 };
 138
 139 static int ath79_gpio_probe(struct platform_device *pdev)
 140 {
 141         struct ath79_gpio_platform_data *pdata = pdev->dev.platform_data;
 142         struct device_node *np = pdev->dev.of_node;
 143         struct ath79_gpio_ctrl *ctrl;
 144         struct resource *res;
 145         u32 ath79_gpio_count;
 146         bool oe_inverted;
 147         int err;
 148
 149         ctrl = devm_kzalloc(&pdev->dev, sizeof(*ctrl), GFP_KERNEL);
 150         if (!ctrl)
 151                 return -ENOMEM;
 152
 153         if (np) {
 154                 err = of_property_read_u32(np, "ngpios", &ath79_gpio_count);
 155                 if (err) {
 156                         dev_err(&pdev->dev, "ngpios property is not valid\n");
 157                         return err;
 158                 }
 159                 if (ath79_gpio_count >= 32) {
 160                         dev_err(&pdev->dev, "ngpios must be less than 32\n");
 161                         return -EINVAL;
 162                 }
 163                 oe_inverted = of_device_is_compatible(np, "qca,ar9340-gpio");
 164         } else if (pdata) {
 165                 ath79_gpio_count = pdata->ngpios;
 166                 oe_inverted = pdata->oe_inverted;
 167         } else {
 168                 dev_err(&pdev->dev, "No DT node or platform data found\n");
 169                 return -EINVAL;
 170         }
 171
 172         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 173         ctrl->base = devm_ioremap_nocache(
 174                 &pdev->dev, res->start, resource_size(res));
 175         if (!ctrl->base)
 176                 return -ENOMEM;
 177
 178         spin_lock_init(&ctrl->lock);
 179         memcpy(&ctrl->chip, &ath79_gpio_chip, sizeof(ctrl->chip));
 180         ctrl->chip.dev = &pdev->dev;
 181         ctrl->chip.ngpio = ath79_gpio_count;
 182         if (oe_inverted) {
 183                 ctrl->chip.direction_input = ar934x_gpio_direction_input;
 184                 ctrl->chip.direction_output = ar934x_gpio_direction_output;
 185         }
 186
 187         err = gpiochip_add(&ctrl->chip);
 188         if (err) {
 189                 dev_err(&pdev->dev,
 190                         "cannot add AR71xx GPIO chip, error=%d", err);
 191                 return err;
 192         }
 193
 194         return 0;
 195 }
 196
 197 static struct platform_driver ath79_gpio_driver = {
 198         .driver = {
 199                 .name = "ath79-gpio",
 200                 .of_match_table = ath79_gpio_of_match,
 201         },
 202         .probe = ath79_gpio_probe,
 203 };
 204
 205 module_platform_driver(ath79_gpio_driver);