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 #define AR71XX_GPIO_REG_OE              0x00
  20 #define AR71XX_GPIO_REG_IN              0x04
  21 #define AR71XX_GPIO_REG_SET             0x0c
  22 #define AR71XX_GPIO_REG_CLEAR           0x10
  23
  24 struct ath79_gpio_ctrl {
  25         struct gpio_chip gc;
  26         void __iomem *base;
  27         spinlock_t lock;
  28 };
  29
  30 static const struct of_device_id ath79_gpio_of_match[] = {
  31         { .compatible = "qca,ar7100-gpio" },
  32         { .compatible = "qca,ar9340-gpio" },
  33         {},
  34 };
  35
  36 static int ath79_gpio_probe(struct platform_device *pdev)
  37 {
  38         struct ath79_gpio_platform_data *pdata = dev_get_platdata(&pdev->dev);
  39         struct device_node *np = pdev->dev.of_node;
  40         struct ath79_gpio_ctrl *ctrl;
  41         struct resource *res;
  42         u32 ath79_gpio_count;
  43         bool oe_inverted;
  44         int err;
  45
  46         ctrl = devm_kzalloc(&pdev->dev, sizeof(*ctrl), GFP_KERNEL);
  47         if (!ctrl)
  48                 return -ENOMEM;
  49         platform_set_drvdata(pdev, ctrl);
  50
  51         if (np) {
  52                 err = of_property_read_u32(np, "ngpios", &ath79_gpio_count);
  53                 if (err) {
  54                         dev_err(&pdev->dev, "ngpios property is not valid\n");
  55                         return err;
  56                 }
  57                 if (ath79_gpio_count >= 32) {
  58                         dev_err(&pdev->dev, "ngpios must be less than 32\n");
  59                         return -EINVAL;
  60                 }
  61                 oe_inverted = of_device_is_compatible(np, "qca,ar9340-gpio");
  62         } else if (pdata) {
  63                 ath79_gpio_count = pdata->ngpios;
  64                 oe_inverted = pdata->oe_inverted;
  65         } else {
  66                 dev_err(&pdev->dev, "No DT node or platform data found\n");
  67                 return -EINVAL;
  68         }
  69
  70         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  71         ctrl->base = devm_ioremap_nocache(
  72                 &pdev->dev, res->start, resource_size(res));
  73         if (!ctrl->base)
  74                 return -ENOMEM;
  75
  76         spin_lock_init(&ctrl->lock);
  77         err = bgpio_init(&ctrl->gc, &pdev->dev, 4,
  78                         ctrl->base + AR71XX_GPIO_REG_IN,
  79                         ctrl->base + AR71XX_GPIO_REG_SET,
  80                         ctrl->base + AR71XX_GPIO_REG_CLEAR,
  81                         oe_inverted ? NULL : ctrl->base + AR71XX_GPIO_REG_OE,
  82                         oe_inverted ? ctrl->base + AR71XX_GPIO_REG_OE : NULL,
  83                         0);
  84         if (err) {
  85                 dev_err(&pdev->dev, "bgpio_init failed\n");
  86                 return err;
  87         }
  88         /* Use base 0 to stay compatible with legacy platforms */
  89         ctrl->gc.base = 0;
  90
  91         err = gpiochip_add_data(&ctrl->gc, ctrl);
  92         if (err) {
  93                 dev_err(&pdev->dev,
  94                         "cannot add AR71xx GPIO chip, error=%d", err);
  95                 return err;
  96         }
  97
  98         return 0;
  99 }
 100
 101 static int ath79_gpio_remove(struct platform_device *pdev)
 102 {
 103         struct ath79_gpio_ctrl *ctrl = platform_get_drvdata(pdev);
 104
 105         gpiochip_remove(&ctrl->gc);
 106         return 0;
 107 }
 108
 109 static struct platform_driver ath79_gpio_driver = {
 110         .driver = {
 111                 .name = "ath79-gpio",
 112                 .of_match_table = ath79_gpio_of_match,
 113         },
 114         .probe = ath79_gpio_probe,
 115         .remove = ath79_gpio_remove,
 116 };
 117
 118 module_platform_driver(ath79_gpio_driver);