gpio-syscon.c
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/*
* 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");