diff options
Diffstat (limited to 'drivers/gpio/gpio-syscon.c')
| -rw-r--r-- | drivers/gpio/gpio-syscon.c | 191 |
1 files changed, 191 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-syscon.c b/drivers/gpio/gpio-syscon.c new file mode 100644 index 00000000000..b50fe129774 --- /dev/null +++ b/drivers/gpio/gpio-syscon.c @@ -0,0 +1,191 @@ +/* + * SYSCON GPIO driver + * + * Copyright (C) 2014 Alexander Shiyan <shc_work@mail.ru> + * + * 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/err.h> +#include <linux/gpio.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/platform_device.h> +#include <linux/regmap.h> +#include <linux/mfd/syscon.h> + +#define GPIO_SYSCON_FEAT_IN BIT(0) +#define GPIO_SYSCON_FEAT_OUT BIT(1) +#define GPIO_SYSCON_FEAT_DIR BIT(2) + +/* SYSCON driver is designed to use 32-bit wide registers */ +#define SYSCON_REG_SIZE (4) +#define SYSCON_REG_BITS (SYSCON_REG_SIZE * 8) + +/** + * struct syscon_gpio_data - Configuration for the device. + * compatible: SYSCON driver compatible string. + * flags: Set of GPIO_SYSCON_FEAT_ flags: + * GPIO_SYSCON_FEAT_IN: GPIOs supports input, + * GPIO_SYSCON_FEAT_OUT: GPIOs supports output, + * GPIO_SYSCON_FEAT_DIR: GPIOs supports switch direction. + * bit_count: Number of bits used as GPIOs. + * dat_bit_offset: Offset (in bits) to the first GPIO bit. + * dir_bit_offset: Optional offset (in bits) to the first bit to switch + * GPIO direction (Used with GPIO_SYSCON_FEAT_DIR flag). + */ + +struct syscon_gpio_data { + const char *compatible; + unsigned int flags; + unsigned int bit_count; + unsigned int dat_bit_offset; + unsigned int dir_bit_offset; +}; + +struct syscon_gpio_priv { + struct gpio_chip chip; + struct regmap *syscon; + const struct syscon_gpio_data *data; +}; + +static inline struct syscon_gpio_priv *to_syscon_gpio(struct gpio_chip *chip) +{ + return container_of(chip, struct syscon_gpio_priv, chip); +} + +static int syscon_gpio_get(struct gpio_chip *chip, unsigned offset) +{ + struct syscon_gpio_priv *priv = to_syscon_gpio(chip); + unsigned int val, offs = priv->data->dat_bit_offset + offset; + int ret; + + ret = regmap_read(priv->syscon, + (offs / SYSCON_REG_BITS) * SYSCON_REG_SIZE, &val); + if (ret) + return ret; + + return !!(val & BIT(offs % SYSCON_REG_BITS)); +} + +static void syscon_gpio_set(struct gpio_chip *chip, unsigned offset, int val) +{ + struct syscon_gpio_priv *priv = to_syscon_gpio(chip); + unsigned int offs = priv->data->dat_bit_offset + offset; + + regmap_update_bits(priv->syscon, + (offs / SYSCON_REG_BITS) * SYSCON_REG_SIZE, + BIT(offs % SYSCON_REG_BITS), + val ? BIT(offs % SYSCON_REG_BITS) : 0); +} + +static int syscon_gpio_dir_in(struct gpio_chip *chip, unsigned offset) +{ + struct syscon_gpio_priv *priv = to_syscon_gpio(chip); + + if (priv->data->flags & GPIO_SYSCON_FEAT_DIR) { + unsigned int offs = priv->data->dir_bit_offset + offset; + + regmap_update_bits(priv->syscon, + (offs / SYSCON_REG_BITS) * SYSCON_REG_SIZE, + BIT(offs % SYSCON_REG_BITS), 0); + } + + return 0; +} + +static int syscon_gpio_dir_out(struct gpio_chip *chip, unsigned offset, int val) +{ + struct syscon_gpio_priv *priv = to_syscon_gpio(chip); + + if (priv->data->flags & GPIO_SYSCON_FEAT_DIR) { + unsigned int offs = priv->data->dir_bit_offset + offset; + + regmap_update_bits(priv->syscon, + (offs / SYSCON_REG_BITS) * SYSCON_REG_SIZE, + BIT(offs % SYSCON_REG_BITS), + BIT(offs % SYSCON_REG_BITS)); + } + + syscon_gpio_set(chip, offset, val); + + return 0; +} + +static const struct syscon_gpio_data clps711x_mctrl_gpio = { + /* ARM CLPS711X SYSFLG1 Bits 8-10 */ + .compatible = "cirrus,clps711x-syscon1", + .flags = GPIO_SYSCON_FEAT_IN, + .bit_count = 3, + .dat_bit_offset = 0x40 * 8 + 8, +}; + +static const struct of_device_id syscon_gpio_ids[] = { + { + .compatible = "cirrus,clps711x-mctrl-gpio", + .data = &clps711x_mctrl_gpio, + }, + { } +}; +MODULE_DEVICE_TABLE(of, syscon_gpio_ids); + +static int syscon_gpio_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + const struct of_device_id *of_id = of_match_device(syscon_gpio_ids, dev); + struct syscon_gpio_priv *priv; + + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + priv->data = of_id->data; + + priv->syscon = + syscon_regmap_lookup_by_compatible(priv->data->compatible); + if (IS_ERR(priv->syscon)) + return PTR_ERR(priv->syscon); + + priv->chip.dev = dev; + priv->chip.owner = THIS_MODULE; + priv->chip.label = dev_name(dev); + priv->chip.base = -1; + priv->chip.ngpio = priv->data->bit_count; + priv->chip.get = syscon_gpio_get; + if (priv->data->flags & GPIO_SYSCON_FEAT_IN) + priv->chip.direction_input = syscon_gpio_dir_in; + if (priv->data->flags & GPIO_SYSCON_FEAT_OUT) { + priv->chip.set = syscon_gpio_set; + priv->chip.direction_output = syscon_gpio_dir_out; + } + + platform_set_drvdata(pdev, priv); + + return gpiochip_add(&priv->chip); +} + +static int syscon_gpio_remove(struct platform_device *pdev) +{ + struct syscon_gpio_priv *priv = platform_get_drvdata(pdev); + + return gpiochip_remove(&priv->chip); +} + +static struct platform_driver syscon_gpio_driver = { + .driver = { + .name = "gpio-syscon", + .owner = THIS_MODULE, + .of_match_table = syscon_gpio_ids, + }, + .probe = syscon_gpio_probe, + .remove = syscon_gpio_remove, +}; +module_platform_driver(syscon_gpio_driver); + +MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>"); +MODULE_DESCRIPTION("SYSCON GPIO driver"); +MODULE_LICENSE("GPL"); |