drivers/gpio/gpio-lpc18xx.c

   1 /*
   2  * GPIO driver for NXP LPC18xx/43xx.
   3  *
   4  * Copyright (C) 2015 Joachim Eastwood <manabian@gmail.com>
   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 version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  */
  11
  12 #include <linux/clk.h>
  13 #include <linux/gpio/driver.h>
  14 #include <linux/io.h>
  15 #include <linux/module.h>
  16 #include <linux/of.h>
  17 #include <linux/of_gpio.h>
  18 #include <linux/pinctrl/consumer.h>
  19 #include <linux/platform_device.h>
  20
  21 /* LPC18xx GPIO register offsets */
  22 #define LPC18XX_REG_DIR(n)      (0x2000 + n * sizeof(u32))
  23
  24 #define LPC18XX_MAX_PORTS       8
  25 #define LPC18XX_PINS_PER_PORT   32
  26
  27 struct lpc18xx_gpio_chip {
  28         struct gpio_chip gpio;
  29         void __iomem *base;
  30         struct clk *clk;
  31         spinlock_t lock;
  32 };
  33
  34 static void lpc18xx_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
  35 {
  36         struct lpc18xx_gpio_chip *gc = gpiochip_get_data(chip);
  37         writeb(value ? 1 : 0, gc->base + offset);
  38 }
  39
  40 static int lpc18xx_gpio_get(struct gpio_chip *chip, unsigned offset)
  41 {
  42         struct lpc18xx_gpio_chip *gc = gpiochip_get_data(chip);
  43         return !!readb(gc->base + offset);
  44 }
  45
  46 static int lpc18xx_gpio_direction(struct gpio_chip *chip, unsigned offset,
  47                                   bool out)
  48 {
  49         struct lpc18xx_gpio_chip *gc = gpiochip_get_data(chip);
  50         unsigned long flags;
  51         u32 port, pin, dir;
  52
  53         port = offset / LPC18XX_PINS_PER_PORT;
  54         pin  = offset % LPC18XX_PINS_PER_PORT;
  55
  56         spin_lock_irqsave(&gc->lock, flags);
  57         dir = readl(gc->base + LPC18XX_REG_DIR(port));
  58         if (out)
  59                 dir |= BIT(pin);
  60         else
  61                 dir &= ~BIT(pin);
  62         writel(dir, gc->base + LPC18XX_REG_DIR(port));
  63         spin_unlock_irqrestore(&gc->lock, flags);
  64
  65         return 0;
  66 }
  67
  68 static int lpc18xx_gpio_direction_input(struct gpio_chip *chip,
  69                                         unsigned offset)
  70 {
  71         return lpc18xx_gpio_direction(chip, offset, false);
  72 }
  73
  74 static int lpc18xx_gpio_direction_output(struct gpio_chip *chip,
  75                                          unsigned offset, int value)
  76 {
  77         lpc18xx_gpio_set(chip, offset, value);
  78         return lpc18xx_gpio_direction(chip, offset, true);
  79 }
  80
  81 static struct gpio_chip lpc18xx_chip = {
  82         .label                  = "lpc18xx/43xx-gpio",
  83         .request                = gpiochip_generic_request,
  84         .free                   = gpiochip_generic_free,
  85         .direction_input        = lpc18xx_gpio_direction_input,
  86         .direction_output       = lpc18xx_gpio_direction_output,
  87         .set                    = lpc18xx_gpio_set,
  88         .get                    = lpc18xx_gpio_get,
  89         .ngpio                  = LPC18XX_MAX_PORTS * LPC18XX_PINS_PER_PORT,
  90         .owner                  = THIS_MODULE,
  91 };
  92
  93 static int lpc18xx_gpio_probe(struct platform_device *pdev)
  94 {
  95         struct lpc18xx_gpio_chip *gc;
  96         struct resource *res;
  97         int ret;
  98
  99         gc = devm_kzalloc(&pdev->dev, sizeof(*gc), GFP_KERNEL);
 100         if (!gc)
 101                 return -ENOMEM;
 102
 103         gc->gpio = lpc18xx_chip;
 104         platform_set_drvdata(pdev, gc);
 105
 106         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 107         gc->base = devm_ioremap_resource(&pdev->dev, res);
 108         if (IS_ERR(gc->base))
 109                 return PTR_ERR(gc->base);
 110
 111         gc->clk = devm_clk_get(&pdev->dev, NULL);
 112         if (IS_ERR(gc->clk)) {
 113                 dev_err(&pdev->dev, "input clock not found\n");
 114                 return PTR_ERR(gc->clk);
 115         }
 116
 117         ret = clk_prepare_enable(gc->clk);
 118         if (ret) {
 119                 dev_err(&pdev->dev, "unable to enable clock\n");
 120                 return ret;
 121         }
 122
 123         spin_lock_init(&gc->lock);
 124
 125         gc->gpio.parent = &pdev->dev;
 126
 127         ret = gpiochip_add_data(&gc->gpio, gc);
 128         if (ret) {
 129                 dev_err(&pdev->dev, "failed to add gpio chip\n");
 130                 clk_disable_unprepare(gc->clk);
 131                 return ret;
 132         }
 133
 134         return 0;
 135 }
 136
 137 static int lpc18xx_gpio_remove(struct platform_device *pdev)
 138 {
 139         struct lpc18xx_gpio_chip *gc = platform_get_drvdata(pdev);
 140
 141         gpiochip_remove(&gc->gpio);
 142         clk_disable_unprepare(gc->clk);
 143
 144         return 0;
 145 }
 146
 147 static const struct of_device_id lpc18xx_gpio_match[] = {
 148         { .compatible = "nxp,lpc1850-gpio" },
 149         { }
 150 };
 151 MODULE_DEVICE_TABLE(of, lpc18xx_gpio_match);
 152
 153 static struct platform_driver lpc18xx_gpio_driver = {
 154         .probe  = lpc18xx_gpio_probe,
 155         .remove = lpc18xx_gpio_remove,
 156         .driver = {
 157                 .name           = "lpc18xx-gpio",
 158                 .of_match_table = lpc18xx_gpio_match,
 159         },
 160 };
 161 module_platform_driver(lpc18xx_gpio_driver);
 162
 163 MODULE_AUTHOR("Joachim Eastwood <manabian@gmail.com>");
 164 MODULE_DESCRIPTION("GPIO driver for LPC18xx/43xx");
 165 MODULE_LICENSE("GPL v2");