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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Congatec Board Controller GPIO driver
*
* Copyright (C) 2024 Bootlin
* Author: Thomas Richard <thomas.richard@bootlin.com>
*/
#include <linux/gpio/driver.h>
#include <linux/mfd/cgbc.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>
#define CGBC_GPIO_NGPIO 14
#define CGBC_GPIO_CMD_GET 0x64
#define CGBC_GPIO_CMD_SET 0x65
#define CGBC_GPIO_CMD_DIR_GET 0x66
#define CGBC_GPIO_CMD_DIR_SET 0x67
struct cgbc_gpio_data {
struct gpio_chip chip;
struct cgbc_device_data *cgbc;
struct mutex lock;
};
static int cgbc_gpio_cmd(struct cgbc_device_data *cgbc,
u8 cmd0, u8 cmd1, u8 cmd2, u8 *value)
{
u8 cmd[3] = {cmd0, cmd1, cmd2};
return cgbc_command(cgbc, cmd, sizeof(cmd), value, 1, NULL);
}
static int cgbc_gpio_get(struct gpio_chip *chip, unsigned int offset)
{
struct cgbc_gpio_data *gpio = gpiochip_get_data(chip);
struct cgbc_device_data *cgbc = gpio->cgbc;
int ret;
u8 val;
scoped_guard(mutex, &gpio->lock)
ret = cgbc_gpio_cmd(cgbc, CGBC_GPIO_CMD_GET, (offset > 7) ? 1 : 0, 0, &val);
offset %= 8;
if (ret)
return ret;
else
return (int)(val & (u8)BIT(offset));
}
static void __cgbc_gpio_set(struct gpio_chip *chip,
unsigned int offset, int value)
{
struct cgbc_gpio_data *gpio = gpiochip_get_data(chip);
struct cgbc_device_data *cgbc = gpio->cgbc;
u8 val;
int ret;
ret = cgbc_gpio_cmd(cgbc, CGBC_GPIO_CMD_GET, (offset > 7) ? 1 : 0, 0, &val);
if (ret)
return;
if (value)
val |= BIT(offset % 8);
else
val &= ~(BIT(offset % 8));
cgbc_gpio_cmd(cgbc, CGBC_GPIO_CMD_SET, (offset > 7) ? 1 : 0, val, &val);
}
static void cgbc_gpio_set(struct gpio_chip *chip,
unsigned int offset, int value)
{
struct cgbc_gpio_data *gpio = gpiochip_get_data(chip);
scoped_guard(mutex, &gpio->lock)
__cgbc_gpio_set(chip, offset, value);
}
static int cgbc_gpio_direction_set(struct gpio_chip *chip,
unsigned int offset, int direction)
{
struct cgbc_gpio_data *gpio = gpiochip_get_data(chip);
struct cgbc_device_data *cgbc = gpio->cgbc;
int ret;
u8 val;
ret = cgbc_gpio_cmd(cgbc, CGBC_GPIO_CMD_DIR_GET, (offset > 7) ? 1 : 0, 0, &val);
if (ret)
goto end;
if (direction == GPIO_LINE_DIRECTION_IN)
val &= ~(BIT(offset % 8));
else
val |= BIT(offset % 8);
ret = cgbc_gpio_cmd(cgbc, CGBC_GPIO_CMD_DIR_SET, (offset > 7) ? 1 : 0, val, &val);
end:
return ret;
}
static int cgbc_gpio_direction_input(struct gpio_chip *chip,
unsigned int offset)
{
struct cgbc_gpio_data *gpio = gpiochip_get_data(chip);
guard(mutex)(&gpio->lock);
return cgbc_gpio_direction_set(chip, offset, GPIO_LINE_DIRECTION_IN);
}
static int cgbc_gpio_direction_output(struct gpio_chip *chip,
unsigned int offset, int value)
{
struct cgbc_gpio_data *gpio = gpiochip_get_data(chip);
guard(mutex)(&gpio->lock);
__cgbc_gpio_set(chip, offset, value);
return cgbc_gpio_direction_set(chip, offset, GPIO_LINE_DIRECTION_OUT);
}
static int cgbc_gpio_get_direction(struct gpio_chip *chip, unsigned int offset)
{
struct cgbc_gpio_data *gpio = gpiochip_get_data(chip);
struct cgbc_device_data *cgbc = gpio->cgbc;
int ret;
u8 val;
scoped_guard(mutex, &gpio->lock)
ret = cgbc_gpio_cmd(cgbc, CGBC_GPIO_CMD_DIR_GET, (offset > 7) ? 1 : 0, 0, &val);
if (ret)
return ret;
if (val & BIT(offset % 8))
return GPIO_LINE_DIRECTION_OUT;
else
return GPIO_LINE_DIRECTION_IN;
}
static int cgbc_gpio_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct cgbc_device_data *cgbc = dev_get_drvdata(dev->parent);
struct cgbc_gpio_data *gpio;
struct gpio_chip *chip;
int ret;
gpio = devm_kzalloc(dev, sizeof(*gpio), GFP_KERNEL);
if (!gpio)
return -ENOMEM;
gpio->cgbc = cgbc;
platform_set_drvdata(pdev, gpio);
chip = &gpio->chip;
chip->label = dev_name(&pdev->dev);
chip->owner = THIS_MODULE;
chip->parent = dev;
chip->base = -1;
chip->direction_input = cgbc_gpio_direction_input;
chip->direction_output = cgbc_gpio_direction_output;
chip->get_direction = cgbc_gpio_get_direction;
chip->get = cgbc_gpio_get;
chip->set = cgbc_gpio_set;
chip->ngpio = CGBC_GPIO_NGPIO;
ret = devm_mutex_init(dev, &gpio->lock);
if (ret)
return ret;
ret = devm_gpiochip_add_data(dev, chip, gpio);
if (ret)
return dev_err_probe(dev, ret, "Could not register GPIO chip\n");
return 0;
}
static struct platform_driver cgbc_gpio_driver = {
.driver = {
.name = "cgbc-gpio",
},
.probe = cgbc_gpio_probe,
};
module_platform_driver(cgbc_gpio_driver);
MODULE_DESCRIPTION("Congatec Board Controller GPIO Driver");
MODULE_AUTHOR("Thomas Richard <thomas.richard@bootlin.com>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:cgbc-gpio");
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