target/linux/ramips/files/arch/mips/ralink/common/gpio.c

   1 /*
   2  * Ralink SoC specific GPIO support
   3  *
   4  * Copyright (C) 2009-2011 Gabor Juhos <juhosg@openwrt.org>
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 as published
   8  * by the Free Software Foundation.
   9  */
  10
  11 #include <linux/init.h>
  12 #include <linux/io.h>
  13
  14 #include <asm/mach-ralink/ramips_gpio.h>
  15
  16 static inline struct ramips_gpio_chip *to_ramips_gpio(struct gpio_chip *chip)
  17 {
  18         struct ramips_gpio_chip *rg;
  19
  20         rg = container_of(chip, struct ramips_gpio_chip, chip);
  21         return rg;
  22 }
  23
  24 static inline void ramips_gpio_wr(struct ramips_gpio_chip *rg, u8 reg, u32 val)
  25 {
  26         __raw_writel(val, rg->regs_base + rg->regs[reg]);
  27 }
  28
  29 static inline u32 ramips_gpio_rr(struct ramips_gpio_chip *rg, u8 reg)
  30 {
  31         return __raw_readl(rg->regs_base + rg->regs[reg]);
  32 }
  33
  34 static int ramips_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
  35 {
  36         struct ramips_gpio_chip *rg = to_ramips_gpio(chip);
  37         unsigned long flags;
  38         u32 t;
  39
  40         spin_lock_irqsave(&rg->lock, flags);
  41         t = ramips_gpio_rr(rg, RAMIPS_GPIO_REG_DIR);
  42         t &= ~(1 << offset);
  43         ramips_gpio_wr(rg, RAMIPS_GPIO_REG_DIR, t);
  44         spin_unlock_irqrestore(&rg->lock, flags);
  45
  46         return 0;
  47 }
  48
  49 static int ramips_gpio_direction_output(struct gpio_chip *chip,
  50                                         unsigned offset, int value)
  51 {
  52         struct ramips_gpio_chip *rg = to_ramips_gpio(chip);
  53         unsigned long flags;
  54         u32 reg;
  55         u32 t;
  56
  57         reg = (value) ? RAMIPS_GPIO_REG_SET : RAMIPS_GPIO_REG_RESET;
  58
  59         spin_lock_irqsave(&rg->lock, flags);
  60         ramips_gpio_wr(rg, reg, 1 << offset);
  61
  62         t = ramips_gpio_rr(rg, RAMIPS_GPIO_REG_DIR);
  63         t |= 1 << offset;
  64         ramips_gpio_wr(rg, RAMIPS_GPIO_REG_DIR, t);
  65         spin_unlock_irqrestore(&rg->lock, flags);
  66
  67         return 0;
  68 }
  69
  70 static void ramips_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
  71 {
  72         struct ramips_gpio_chip *rg = to_ramips_gpio(chip);
  73         u32 reg;
  74
  75         reg = (value) ? RAMIPS_GPIO_REG_SET : RAMIPS_GPIO_REG_RESET;
  76         ramips_gpio_wr(rg, reg, 1 << offset);
  77 }
  78
  79 static int ramips_gpio_get(struct gpio_chip *chip, unsigned offset)
  80 {
  81         struct ramips_gpio_chip *rg = to_ramips_gpio(chip);
  82         u32 t;
  83
  84         t = ramips_gpio_rr(rg, RAMIPS_GPIO_REG_DATA);
  85         return !!(t & (1 << offset));
  86 }
  87
  88 static __init void ramips_gpio_chip_add(struct ramips_gpio_chip *rg)
  89 {
  90         spin_lock_init(&rg->lock);
  91
  92         rg->regs_base = ioremap(rg->map_base, rg->map_size);
  93
  94         rg->chip.direction_input = ramips_gpio_direction_input;
  95         rg->chip.direction_output = ramips_gpio_direction_output;
  96         rg->chip.get = ramips_gpio_get;
  97         rg->chip.set = ramips_gpio_set;
  98
  99         /* set polarity to low for all lines */
 100         ramips_gpio_wr(rg, RAMIPS_GPIO_REG_POL, 0);
 101
 102         gpiochip_add(&rg->chip);
 103 }
 104
 105 __init int ramips_gpio_init(struct ramips_gpio_data *data)
 106 {
 107         int i;
 108
 109         for (i = 0; i < data->num_chips; i++)
 110                 ramips_gpio_chip_add(&data->chips[i]);
 111
 112         return 0;
 113 }