diff options
Diffstat (limited to 'drivers/gpio/gpio-lpc18xx.c')
| -rw-r--r-- | drivers/gpio/gpio-lpc18xx.c | 180 |
1 files changed, 180 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-lpc18xx.c b/drivers/gpio/gpio-lpc18xx.c new file mode 100644 index 000000000..eb6860313 --- /dev/null +++ b/drivers/gpio/gpio-lpc18xx.c @@ -0,0 +1,180 @@ +/* + * GPIO driver for NXP LPC18xx/43xx. + * + * Copyright (C) 2015 Joachim Eastwood <manabian@gmail.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + */ + +#include <linux/clk.h> +#include <linux/gpio/driver.h> +#include <linux/io.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/of_gpio.h> +#include <linux/pinctrl/consumer.h> +#include <linux/platform_device.h> + +/* LPC18xx GPIO register offsets */ +#define LPC18XX_REG_DIR(n) (0x2000 + n * sizeof(u32)) + +#define LPC18XX_MAX_PORTS 8 +#define LPC18XX_PINS_PER_PORT 32 + +struct lpc18xx_gpio_chip { + struct gpio_chip gpio; + void __iomem *base; + struct clk *clk; + spinlock_t lock; +}; + +static inline struct lpc18xx_gpio_chip *to_lpc18xx_gpio(struct gpio_chip *chip) +{ + return container_of(chip, struct lpc18xx_gpio_chip, gpio); +} + +static int lpc18xx_gpio_request(struct gpio_chip *chip, unsigned offset) +{ + return pinctrl_request_gpio(offset); +} + +static void lpc18xx_gpio_free(struct gpio_chip *chip, unsigned offset) +{ + pinctrl_free_gpio(offset); +} + +static void lpc18xx_gpio_set(struct gpio_chip *chip, unsigned offset, int value) +{ + struct lpc18xx_gpio_chip *gc = to_lpc18xx_gpio(chip); + writeb(value ? 1 : 0, gc->base + offset); +} + +static int lpc18xx_gpio_get(struct gpio_chip *chip, unsigned offset) +{ + struct lpc18xx_gpio_chip *gc = to_lpc18xx_gpio(chip); + return !!readb(gc->base + offset); +} + +static int lpc18xx_gpio_direction(struct gpio_chip *chip, unsigned offset, + bool out) +{ + struct lpc18xx_gpio_chip *gc = to_lpc18xx_gpio(chip); + unsigned long flags; + u32 port, pin, dir; + + port = offset / LPC18XX_PINS_PER_PORT; + pin = offset % LPC18XX_PINS_PER_PORT; + + spin_lock_irqsave(&gc->lock, flags); + dir = readl(gc->base + LPC18XX_REG_DIR(port)); + if (out) + dir |= BIT(pin); + else + dir &= ~BIT(pin); + writel(dir, gc->base + LPC18XX_REG_DIR(port)); + spin_unlock_irqrestore(&gc->lock, flags); + + return 0; +} + +static int lpc18xx_gpio_direction_input(struct gpio_chip *chip, + unsigned offset) +{ + return lpc18xx_gpio_direction(chip, offset, false); +} + +static int lpc18xx_gpio_direction_output(struct gpio_chip *chip, + unsigned offset, int value) +{ + lpc18xx_gpio_set(chip, offset, value); + return lpc18xx_gpio_direction(chip, offset, true); +} + +static struct gpio_chip lpc18xx_chip = { + .label = "lpc18xx/43xx-gpio", + .request = lpc18xx_gpio_request, + .free = lpc18xx_gpio_free, + .direction_input = lpc18xx_gpio_direction_input, + .direction_output = lpc18xx_gpio_direction_output, + .set = lpc18xx_gpio_set, + .get = lpc18xx_gpio_get, + .ngpio = LPC18XX_MAX_PORTS * LPC18XX_PINS_PER_PORT, + .owner = THIS_MODULE, +}; + +static int lpc18xx_gpio_probe(struct platform_device *pdev) +{ + struct lpc18xx_gpio_chip *gc; + struct resource *res; + int ret; + + gc = devm_kzalloc(&pdev->dev, sizeof(*gc), GFP_KERNEL); + if (!gc) + return -ENOMEM; + + gc->gpio = lpc18xx_chip; + platform_set_drvdata(pdev, gc); + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + gc->base = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(gc->base)) + return PTR_ERR(gc->base); + + gc->clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(gc->clk)) { + dev_err(&pdev->dev, "input clock not found\n"); + return PTR_ERR(gc->clk); + } + + ret = clk_prepare_enable(gc->clk); + if (ret) { + dev_err(&pdev->dev, "unable to enable clock\n"); + return ret; + } + + spin_lock_init(&gc->lock); + + gc->gpio.dev = &pdev->dev; + + ret = gpiochip_add(&gc->gpio); + if (ret) { + dev_err(&pdev->dev, "failed to add gpio chip\n"); + clk_disable_unprepare(gc->clk); + return ret; + } + + return 0; +} + +static int lpc18xx_gpio_remove(struct platform_device *pdev) +{ + struct lpc18xx_gpio_chip *gc = platform_get_drvdata(pdev); + + gpiochip_remove(&gc->gpio); + clk_disable_unprepare(gc->clk); + + return 0; +} + +static const struct of_device_id lpc18xx_gpio_match[] = { + { .compatible = "nxp,lpc1850-gpio" }, + { } +}; +MODULE_DEVICE_TABLE(of, lpc18xx_gpio_match); + +static struct platform_driver lpc18xx_gpio_driver = { + .probe = lpc18xx_gpio_probe, + .remove = lpc18xx_gpio_remove, + .driver = { + .name = "lpc18xx-gpio", + .of_match_table = lpc18xx_gpio_match, + }, +}; +module_platform_driver(lpc18xx_gpio_driver); + +MODULE_AUTHOR("Joachim Eastwood <manabian@gmail.com>"); +MODULE_DESCRIPTION("GPIO driver for LPC18xx/43xx"); +MODULE_LICENSE("GPL v2"); |