LXR linux/drivers/gpio/gpio-iop.c

   1/*
   2 * arch/arm/plat-iop/gpio.c
   3 * GPIO handling for Intel IOP3xx processors.
   4 *
   5 * Copyright (C) 2006 Lennert Buytenhek <buytenh@wantstofly.org>
   6 *
   7 * This program is free software; you can redistribute it and/or modify
   8 * it under the terms of the GNU General Public License as published by
   9 * the Free Software Foundation; either version 2 of the License, or (at
  10 * your option) any later version.
  11 */
  12
  13#include <linux/device.h>
  14#include <linux/init.h>
  15#include <linux/types.h>
  16#include <linux/errno.h>
  17#include <linux/gpio.h>
  18#include <linux/export.h>
  19#include <linux/platform_device.h>
  20#include <linux/bitops.h>
  21#include <linux/io.h>
  22
  23#define IOP3XX_N_GPIOS  8
  24
  25#define GPIO_IN                 0
  26#define GPIO_OUT                1
  27#define GPIO_LOW                0
  28#define GPIO_HIGH               1
  29
  30/* Memory base offset */
  31static void __iomem *base;
  32
  33#define IOP3XX_GPIO_REG(reg)    (base + (reg))
  34#define IOP3XX_GPOE             IOP3XX_GPIO_REG(0x0000)
  35#define IOP3XX_GPID             IOP3XX_GPIO_REG(0x0004)
  36#define IOP3XX_GPOD             IOP3XX_GPIO_REG(0x0008)
  37
  38static void gpio_line_config(int line, int direction)
  39{
  40        unsigned long flags;
  41        u32 val;
  42
  43        local_irq_save(flags);
  44        val = readl(IOP3XX_GPOE);
  45        if (direction == GPIO_IN) {
  46                val |= BIT(line);
  47        } else if (direction == GPIO_OUT) {
  48                val &= ~BIT(line);
  49        }
  50        writel(val, IOP3XX_GPOE);
  51        local_irq_restore(flags);
  52}
  53
  54static int gpio_line_get(int line)
  55{
  56        return !!(readl(IOP3XX_GPID) & BIT(line));
  57}
  58
  59static void gpio_line_set(int line, int value)
  60{
  61        unsigned long flags;
  62        u32 val;
  63
  64        local_irq_save(flags);
  65        val = readl(IOP3XX_GPOD);
  66        if (value == GPIO_LOW) {
  67                val &= ~BIT(line);
  68        } else if (value == GPIO_HIGH) {
  69                val |= BIT(line);
  70        }
  71        writel(val, IOP3XX_GPOD);
  72        local_irq_restore(flags);
  73}
  74
  75static int iop3xx_gpio_direction_input(struct gpio_chip *chip, unsigned gpio)
  76{
  77        gpio_line_config(gpio, GPIO_IN);
  78        return 0;
  79}
  80
  81static int iop3xx_gpio_direction_output(struct gpio_chip *chip, unsigned gpio, int level)
  82{
  83        gpio_line_set(gpio, level);
  84        gpio_line_config(gpio, GPIO_OUT);
  85        return 0;
  86}
  87
  88static int iop3xx_gpio_get_value(struct gpio_chip *chip, unsigned gpio)
  89{
  90        return gpio_line_get(gpio);
  91}
  92
  93static void iop3xx_gpio_set_value(struct gpio_chip *chip, unsigned gpio, int value)
  94{
  95        gpio_line_set(gpio, value);
  96}
  97
  98static struct gpio_chip iop3xx_chip = {
  99        .label                  = "iop3xx",
 100        .direction_input        = iop3xx_gpio_direction_input,
 101        .get                    = iop3xx_gpio_get_value,
 102        .direction_output       = iop3xx_gpio_direction_output,
 103        .set                    = iop3xx_gpio_set_value,
 104        .base                   = 0,
 105        .ngpio                  = IOP3XX_N_GPIOS,
 106};
 107
 108static int iop3xx_gpio_probe(struct platform_device *pdev)
 109{
 110        struct resource *res;
 111
 112        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 113        base = devm_ioremap_resource(&pdev->dev, res);
 114        if (IS_ERR(base))
 115                return PTR_ERR(base);
 116
 117        return gpiochip_add(&iop3xx_chip);
 118}
 119
 120static struct platform_driver iop3xx_gpio_driver = {
 121        .driver = {
 122                .name = "gpio-iop",
 123        },
 124        .probe = iop3xx_gpio_probe,
 125};
 126
 127static int __init iop3xx_gpio_init(void)
 128{
 129        return platform_driver_register(&iop3xx_gpio_driver);
 130}
 131arch_initcall(iop3xx_gpio_init);
 132