release/src-rt-6.x.4708/linux/linux-2.6.36/arch/mips/ar7/gpio.c

   1 /*
   2  * Copyright (C) 2007 Felix Fietkau <nbd@openwrt.org>
   3  * Copyright (C) 2007 Eugene Konev <ejka@openwrt.org>
   4  * Copyright (C) 2009 Florian Fainelli <florian@openwrt.org>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  19  */
  20
  21 #include <linux/module.h>
  22 #include <linux/gpio.h>
  23
  24 #include <asm/mach-ar7/gpio.h>
  25
  26 struct ar7_gpio_chip {
  27         void __iomem            *regs;
  28         struct gpio_chip        chip;
  29 };
  30
  31 static int ar7_gpio_get_value(struct gpio_chip *chip, unsigned gpio)
  32 {
  33         struct ar7_gpio_chip *gpch =
  34                                 container_of(chip, struct ar7_gpio_chip, chip);
  35         void __iomem *gpio_in = gpch->regs + AR7_GPIO_INPUT;
  36
  37         return readl(gpio_in) & (1 << gpio);
  38 }
  39
  40 static void ar7_gpio_set_value(struct gpio_chip *chip,
  41                                 unsigned gpio, int value)
  42 {
  43         struct ar7_gpio_chip *gpch =
  44                                 container_of(chip, struct ar7_gpio_chip, chip);
  45         void __iomem *gpio_out = gpch->regs + AR7_GPIO_OUTPUT;
  46         unsigned tmp;
  47
  48         tmp = readl(gpio_out) & ~(1 << gpio);
  49         if (value)
  50                 tmp |= 1 << gpio;
  51         writel(tmp, gpio_out);
  52 }
  53
  54 static int ar7_gpio_direction_input(struct gpio_chip *chip, unsigned gpio)
  55 {
  56         struct ar7_gpio_chip *gpch =
  57                                 container_of(chip, struct ar7_gpio_chip, chip);
  58         void __iomem *gpio_dir = gpch->regs + AR7_GPIO_DIR;
  59
  60         writel(readl(gpio_dir) | (1 << gpio), gpio_dir);
  61
  62         return 0;
  63 }
  64
  65 static int ar7_gpio_direction_output(struct gpio_chip *chip,
  66                                         unsigned gpio, int value)
  67 {
  68         struct ar7_gpio_chip *gpch =
  69                                 container_of(chip, struct ar7_gpio_chip, chip);
  70         void __iomem *gpio_dir = gpch->regs + AR7_GPIO_DIR;
  71
  72         ar7_gpio_set_value(chip, gpio, value);
  73         writel(readl(gpio_dir) & ~(1 << gpio), gpio_dir);
  74
  75         return 0;
  76 }
  77
  78 static struct ar7_gpio_chip ar7_gpio_chip = {
  79         .chip = {
  80                 .label                  = "ar7-gpio",
  81                 .direction_input        = ar7_gpio_direction_input,
  82                 .direction_output       = ar7_gpio_direction_output,
  83                 .set                    = ar7_gpio_set_value,
  84                 .get                    = ar7_gpio_get_value,
  85                 .base                   = 0,
  86                 .ngpio                  = AR7_GPIO_MAX,
  87         }
  88 };
  89
  90 int ar7_gpio_enable(unsigned gpio)
  91 {
  92         void __iomem *gpio_en = ar7_gpio_chip.regs + AR7_GPIO_ENABLE;
  93
  94         writel(readl(gpio_en) | (1 << gpio), gpio_en);
  95
  96         return 0;
  97 }
  98 EXPORT_SYMBOL(ar7_gpio_enable);
  99
 100 int ar7_gpio_disable(unsigned gpio)
 101 {
 102         void __iomem *gpio_en = ar7_gpio_chip.regs + AR7_GPIO_ENABLE;
 103
 104         writel(readl(gpio_en) & ~(1 << gpio), gpio_en);
 105
 106         return 0;
 107 }
 108 EXPORT_SYMBOL(ar7_gpio_disable);
 109
 110 static int __init ar7_gpio_init(void)
 111 {
 112         int ret;
 113
 114         ar7_gpio_chip.regs = ioremap_nocache(AR7_REGS_GPIO, 0x10);
 115
 116         if (!ar7_gpio_chip.regs) {
 117                 printk(KERN_ERR "ar7-gpio: failed to ioremap regs\n");
 118         }
 119
 120         ret = gpiochip_add(&ar7_gpio_chip.chip);
 121         if (ret) {
 122                 printk(KERN_ERR "ar7-gpio: failed to add gpiochip\n");
 123                 return ret;
 124         }
 125         printk(KERN_INFO "ar7-gpio: registered %d GPIOs\n",
 126                                 ar7_gpio_chip.chip.ngpio);
 127         return ret;
 128 }
 129 arch_initcall(ar7_gpio_init);