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 inline struct lpc18xx_gpio_chip *to_lpc18xx_gpio(struct gpio_chip *chip)
  35 {
  36         return container_of(chip, struct lpc18xx_gpio_chip, gpio);
  37 }
  38
  39 static void lpc18xx_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
  40 {
  41         struct lpc18xx_gpio_chip *gc = to_lpc18xx_gpio(chip);
  42         writeb(value ? 1 : 0, gc->base + offset);
  43 }
  44
  45 static int lpc18xx_gpio_get(struct gpio_chip *chip, unsigned offset)
  46 {
  47         struct lpc18xx_gpio_chip *gc = to_lpc18xx_gpio(chip);
  48         return !!readb(gc->base + offset);
  49 }
  50
  51 static int lpc18xx_gpio_direction(struct gpio_chip *chip, unsigned offset,
  52                                   bool out)
  53 {
  54         struct lpc18xx_gpio_chip *gc = to_lpc18xx_gpio(chip);
  55         unsigned long flags;
  56         u32 port, pin, dir;
  57
  58         port = offset / LPC18XX_PINS_PER_PORT;
  59         pin  = offset % LPC18XX_PINS_PER_PORT;
  60
  61         spin_lock_irqsave(&gc->lock, flags);
  62         dir = readl(gc->base + LPC18XX_REG_DIR(port));
  63         if (out)
  64                 dir |= BIT(pin);
  65         else
  66                 dir &= ~BIT(pin);
  67         writel(dir, gc->base + LPC18XX_REG_DIR(port));
  68         spin_unlock_irqrestore(&gc->lock, flags);
  69
  70         return 0;
  71 }
  72
  73 static int lpc18xx_gpio_direction_input(struct gpio_chip *chip,
  74                                         unsigned offset)
  75 {
  76         return lpc18xx_gpio_direction(chip, offset, false);
  77 }
  78
  79 static int lpc18xx_gpio_direction_output(struct gpio_chip *chip,
  80                                          unsigned offset, int value)
  81 {
  82         lpc18xx_gpio_set(chip, offset, value);
  83         return lpc18xx_gpio_direction(chip, offset, true);
  84 }
  85
  86 static struct gpio_chip lpc18xx_chip = {
  87         .label                  = "lpc18xx/43xx-gpio",
  88         .request                = gpiochip_generic_request,
  89         .free                   = gpiochip_generic_free,
  90         .direction_input        = lpc18xx_gpio_direction_input,
  91         .direction_output       = lpc18xx_gpio_direction_output,
  92         .set                    = lpc18xx_gpio_set,
  93         .get                    = lpc18xx_gpio_get,
  94         .ngpio                  = LPC18XX_MAX_PORTS * LPC18XX_PINS_PER_PORT,
  95         .owner                  = THIS_MODULE,
  96 };
  97
  98 static int lpc18xx_gpio_probe(struct platform_device *pdev)
  99 {
 100         struct lpc18xx_gpio_chip *gc;
 101         struct resource *res;
 102         int ret;
 103
 104         gc = devm_kzalloc(&pdev->dev, sizeof(*gc), GFP_KERNEL);
 105         if (!gc)
 106                 return -ENOMEM;
 107
 108         gc->gpio = lpc18xx_chip;
 109         platform_set_drvdata(pdev, gc);
 110
 111         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 112         gc->base = devm_ioremap_resource(&pdev->dev, res);
 113         if (IS_ERR(gc->base))
 114                 return PTR_ERR(gc->base);
 115
 116         gc->clk = devm_clk_get(&pdev->dev, NULL);
 117         if (IS_ERR(gc->clk)) {
 118                 dev_err(&pdev->dev, "input clock not found\n");
 119                 return PTR_ERR(gc->clk);
 120         }
 121
 122         ret = clk_prepare_enable(gc->clk);
 123         if (ret) {
 124                 dev_err(&pdev->dev, "unable to enable clock\n");
 125                 return ret;
 126         }
 127
 128         spin_lock_init(&gc->lock);
 129
 130         gc->gpio.dev = &pdev->dev;
 131
 132         ret = gpiochip_add(&gc->gpio);
 133         if (ret) {
 134                 dev_err(&pdev->dev, "failed to add gpio chip\n");
 135                 clk_disable_unprepare(gc->clk);
 136                 return ret;
 137         }
 138
 139         return 0;
 140 }
 141
 142 static int lpc18xx_gpio_remove(struct platform_device *pdev)
 143 {
 144         struct lpc18xx_gpio_chip *gc = platform_get_drvdata(pdev);
 145
 146         gpiochip_remove(&gc->gpio);
 147         clk_disable_unprepare(gc->clk);
 148
 149         return 0;
 150 }
 151
 152 static const struct of_device_id lpc18xx_gpio_match[] = {
 153         { .compatible = "nxp,lpc1850-gpio" },
 154         { }
 155 };
 156 MODULE_DEVICE_TABLE(of, lpc18xx_gpio_match);
 157
 158 static struct platform_driver lpc18xx_gpio_driver = {
 159         .probe  = lpc18xx_gpio_probe,
 160         .remove = lpc18xx_gpio_remove,
 161         .driver = {
 162                 .name           = "lpc18xx-gpio",
 163                 .of_match_table = lpc18xx_gpio_match,
 164         },
 165 };
 166 module_platform_driver(lpc18xx_gpio_driver);
 167
 168 MODULE_AUTHOR("Joachim Eastwood <manabian@gmail.com>");
 169 MODULE_DESCRIPTION("GPIO driver for LPC18xx/43xx");
 170 MODULE_LICENSE("GPL v2");