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 */
  31 static 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
  38 static 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
  54 static int gpio_line_get(int line)
  55 {
  56         return !!(readl(IOP3XX_GPID) & BIT(line));
  57 }
  58
  59 static 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
  75 static int iop3xx_gpio_direction_input(struct gpio_chip *chip, unsigned gpio)
  76 {
  77         gpio_line_config(gpio, GPIO_IN);
  78         return 0;
  79 }
  80
  81 static 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
  88 static int iop3xx_gpio_get_value(struct gpio_chip *chip, unsigned gpio)
  89 {
  90         return gpio_line_get(gpio);
  91 }
  92
  93 static void iop3xx_gpio_set_value(struct gpio_chip *chip, unsigned gpio, int value)
  94 {
  95         gpio_line_set(gpio, value);
  96 }
  97
  98 static 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
 108 static 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
 115         return gpiochip_add(&iop3xx_chip);
 116 }
 117
 118 static struct platform_driver iop3xx_gpio_driver = {
 119         .driver = {
 120                 .name = "gpio-iop",
 121                 .owner = THIS_MODULE,
 122         },
 123         .probe = iop3xx_gpio_probe,
 124 };
 125
 126 static int __init iop3xx_gpio_init(void)
 127 {
 128         return platform_driver_register(&iop3xx_gpio_driver);
 129 }
 130 arch_initcall(iop3xx_gpio_init);