diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/gpio/gpio-loongson.c | 139 |
1 files changed, 139 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-loongson.c b/drivers/gpio/gpio-loongson.c new file mode 100644 index 000000000..16cfbe9e7 --- /dev/null +++ b/drivers/gpio/gpio-loongson.c @@ -0,0 +1,139 @@ +/* + * Loongson-2F/3A/3B GPIO Support + * + * Copyright (c) 2008 Richard Liu, STMicroelectronics <richard.liu@st.com> + * Copyright (c) 2008-2010 Arnaud Patard <apatard@mandriva.com> + * Copyright (c) 2013 Hongbing Hu <huhb@lemote.com> + * Copyright (c) 2014 Huacai Chen <chenhc@lemote.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + */ + +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/module.h> +#include <linux/spinlock.h> +#include <linux/err.h> +#include <linux/gpio/driver.h> +#include <linux/platform_device.h> +#include <linux/bitops.h> +#include <asm/types.h> +#include <loongson.h> + +#define STLS2F_N_GPIO 4 +#define STLS3A_N_GPIO 16 + +#ifdef CONFIG_CPU_LOONGSON3 +#define LOONGSON_N_GPIO STLS3A_N_GPIO +#else +#define LOONGSON_N_GPIO STLS2F_N_GPIO +#endif + +/* + * Offset into the register where we read lines, we write them from offset 0. + * This offset is the only thing that stand between us and using + * GPIO_GENERIC. + */ +#define LOONGSON_GPIO_IN_OFFSET 16 + +static DEFINE_SPINLOCK(gpio_lock); + +static int loongson_gpio_get_value(struct gpio_chip *chip, unsigned gpio) +{ + u32 val; + + spin_lock(&gpio_lock); + val = LOONGSON_GPIODATA; + spin_unlock(&gpio_lock); + + return !!(val & BIT(gpio + LOONGSON_GPIO_IN_OFFSET)); +} + +static void loongson_gpio_set_value(struct gpio_chip *chip, + unsigned gpio, int value) +{ + u32 val; + + spin_lock(&gpio_lock); + val = LOONGSON_GPIODATA; + if (value) + val |= BIT(gpio); + else + val &= ~BIT(gpio); + LOONGSON_GPIODATA = val; + spin_unlock(&gpio_lock); +} + +static int loongson_gpio_direction_input(struct gpio_chip *chip, unsigned gpio) +{ + u32 temp; + + spin_lock(&gpio_lock); + temp = LOONGSON_GPIOIE; + temp |= BIT(gpio); + LOONGSON_GPIOIE = temp; + spin_unlock(&gpio_lock); + + return 0; +} + +static int loongson_gpio_direction_output(struct gpio_chip *chip, + unsigned gpio, int level) +{ + u32 temp; + + loongson_gpio_set_value(chip, gpio, level); + spin_lock(&gpio_lock); + temp = LOONGSON_GPIOIE; + temp &= ~BIT(gpio); + LOONGSON_GPIOIE = temp; + spin_unlock(&gpio_lock); + + return 0; +} + +static int loongson_gpio_probe(struct platform_device *pdev) +{ + struct gpio_chip *gc; + struct device *dev = &pdev->dev; + + gc = devm_kzalloc(dev, sizeof(*gc), GFP_KERNEL); + if (!gc) + return -ENOMEM; + + gc->label = "loongson-gpio-chip"; + gc->base = 0; + gc->ngpio = LOONGSON_N_GPIO; + gc->get = loongson_gpio_get_value; + gc->set = loongson_gpio_set_value; + gc->direction_input = loongson_gpio_direction_input; + gc->direction_output = loongson_gpio_direction_output; + + return gpiochip_add_data(gc, NULL); +} + +static struct platform_driver loongson_gpio_driver = { + .driver = { + .name = "loongson-gpio", + }, + .probe = loongson_gpio_probe, +}; + +static int __init loongson_gpio_setup(void) +{ + struct platform_device *pdev; + int ret; + + ret = platform_driver_register(&loongson_gpio_driver); + if (ret) { + pr_err("error registering loongson GPIO driver\n"); + return ret; + } + + pdev = platform_device_register_simple("loongson-gpio", -1, NULL, 0); + return PTR_ERR_OR_ZERO(pdev); +} +postcore_initcall(loongson_gpio_setup); |