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 int lpc18xx_gpio_request(struct gpio_chip *chip, unsigned offset)
  40 {
  41         return pinctrl_request_gpio(offset);
  42 }
  43
  44 static void lpc18xx_gpio_free(struct gpio_chip *chip, unsigned offset)
  45 {
  46         pinctrl_free_gpio(offset);
  47 }
  48
  49 static void lpc18xx_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
  50 {
  51         struct lpc18xx_gpio_chip *gc = to_lpc18xx_gpio(chip);
  52         writeb(value ? 1 : 0, gc->base + offset);
  53 }
  54
  55 static int lpc18xx_gpio_get(struct gpio_chip *chip, unsigned offset)
  56 {
  57         struct lpc18xx_gpio_chip *gc = to_lpc18xx_gpio(chip);
  58         return !!readb(gc->base + offset);
  59 }
  60
  61 static int lpc18xx_gpio_direction(struct gpio_chip *chip, unsigned offset,
  62                                   bool out)
  63 {
  64         struct lpc18xx_gpio_chip *gc = to_lpc18xx_gpio(chip);
  65         unsigned long flags;
  66         u32 port, pin, dir;
  67
  68         port = offset / LPC18XX_PINS_PER_PORT;
  69         pin  = offset % LPC18XX_PINS_PER_PORT;
  70
  71         spin_lock_irqsave(&gc->lock, flags);
  72         dir = readl(gc->base + LPC18XX_REG_DIR(port));
  73         if (out)
  74                 dir |= BIT(pin);
  75         else
  76                 dir &= ~BIT(pin);
  77         writel(dir, gc->base + LPC18XX_REG_DIR(port));
  78         spin_unlock_irqrestore(&gc->lock, flags);
  79
  80         return 0;
  81 }
  82
  83 static int lpc18xx_gpio_direction_input(struct gpio_chip *chip,
  84                                         unsigned offset)
  85 {
  86         return lpc18xx_gpio_direction(chip, offset, false);
  87 }
  88
  89 static int lpc18xx_gpio_direction_output(struct gpio_chip *chip,
  90                                          unsigned offset, int value)
  91 {
  92         lpc18xx_gpio_set(chip, offset, value);
  93         return lpc18xx_gpio_direction(chip, offset, true);
  94 }
  95
  96 static struct gpio_chip lpc18xx_chip = {
  97         .label                  = "lpc18xx/43xx-gpio",
  98         .request                = lpc18xx_gpio_request,
  99         .free                   = lpc18xx_gpio_free,
 100         .direction_input        = lpc18xx_gpio_direction_input,
 101         .direction_output       = lpc18xx_gpio_direction_output,
 102         .set                    = lpc18xx_gpio_set,
 103         .get                    = lpc18xx_gpio_get,
 104         .ngpio                  = LPC18XX_MAX_PORTS * LPC18XX_PINS_PER_PORT,
 105         .owner                  = THIS_MODULE,
 106 };
 107
 108 static int lpc18xx_gpio_probe(struct platform_device *pdev)
 109 {
 110         struct lpc18xx_gpio_chip *gc;
 111         struct resource *res;
 112         int ret;
 113
 114         gc = devm_kzalloc(&pdev->dev, sizeof(*gc), GFP_KERNEL);
 115         if (!gc)
 116                 return -ENOMEM;
 117
 118         gc->gpio = lpc18xx_chip;
 119         platform_set_drvdata(pdev, gc);
 120
 121         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 122         gc->base = devm_ioremap_resource(&pdev->dev, res);
 123         if (IS_ERR(gc->base))
 124                 return PTR_ERR(gc->base);
 125
 126         gc->clk = devm_clk_get(&pdev->dev, NULL);
 127         if (IS_ERR(gc->clk)) {
 128                 dev_err(&pdev->dev, "input clock not found\n");
 129                 return PTR_ERR(gc->clk);
 130         }
 131
 132         ret = clk_prepare_enable(gc->clk);
 133         if (ret) {
 134                 dev_err(&pdev->dev, "unable to enable clock\n");
 135                 return ret;
 136         }
 137
 138         spin_lock_init(&gc->lock);
 139
 140         gc->gpio.dev = &pdev->dev;
 141
 142         ret = gpiochip_add(&gc->gpio);
 143         if (ret) {
 144                 dev_err(&pdev->dev, "failed to add gpio chip\n");
 145                 clk_disable_unprepare(gc->clk);
 146                 return ret;
 147         }
 148
 149         return 0;
 150 }
 151
 152 static int lpc18xx_gpio_remove(struct platform_device *pdev)
 153 {
 154         struct lpc18xx_gpio_chip *gc = platform_get_drvdata(pdev);
 155
 156         gpiochip_remove(&gc->gpio);
 157         clk_disable_unprepare(gc->clk);
 158
 159         return 0;
 160 }
 161
 162 static const struct of_device_id lpc18xx_gpio_match[] = {
 163         { .compatible = "nxp,lpc1850-gpio" },
 164         { }
 165 };
 166 MODULE_DEVICE_TABLE(of, lpc18xx_gpio_match);
 167
 168 static struct platform_driver lpc18xx_gpio_driver = {
 169         .probe  = lpc18xx_gpio_probe,
 170         .remove = lpc18xx_gpio_remove,
 171         .driver = {
 172                 .name           = "lpc18xx-gpio",
 173                 .of_match_table = lpc18xx_gpio_match,
 174         },
 175 };
 176 module_platform_driver(lpc18xx_gpio_driver);
 177
 178 MODULE_AUTHOR("Joachim Eastwood <manabian@gmail.com>");
 179 MODULE_DESCRIPTION("GPIO driver for LPC18xx/43xx");
 180 MODULE_LICENSE("GPL v2");