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// SPDX-License-Identifier: GPL-2.0-only
/*
* GPIO driver for the MikroTik RouterBoard 4xx series
*
* Copyright (C) 2008-2011 Gabor Juhos <juhosg@openwrt.org>
* Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
* Copyright (C) 2015 Bert Vermeulen <bert@biot.com>
* Copyright (C) 2020 Christopher Hill <ch6574@gmail.com>
*
* This file was based on the driver for Linux 2.6.22 published by
* MikroTik for their RouterBoard 4xx series devices.
*
* N.B. driver probe reports "DMA mask not set" warnings which are
* an artifact of using a platform_driver as an MFD device child.
* See conversation here https://lkml.org/lkml/2020/4/28/675
*/
#include <linux/platform_device.h>
#include <linux/gpio/driver.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <mfd/rb4xx-cpld.h>
struct rb4xx_gpio {
struct rb4xx_cpld *cpld;
struct device *dev;
struct gpio_chip chip;
struct mutex lock;
u16 values; /* bitfield of GPIO 0-8 current values */
};
static int rb4xx_gpio_cpld_set(struct rb4xx_gpio *gpio, unsigned int offset,
int value)
{
struct rb4xx_cpld *cpld = gpio->cpld;
u16 values;
int ret;
mutex_lock(&gpio->lock);
values = gpio->values;
if (value)
values |= BIT(offset);
else
values &= ~(BIT(offset));
if (values == gpio->values) {
ret = 0;
goto unlock;
}
if (offset < 8) {
ret = cpld->gpio_set_0_7(cpld, values & 0xff);
} else if (offset == 8) {
ret = cpld->gpio_set_8(cpld, values >> 8);
}
if(likely(!ret))
gpio->values = values;
unlock:
mutex_unlock(&gpio->lock);
return ret;
}
static int rb4xx_gpio_get_direction(struct gpio_chip *chip, unsigned int offset)
{
return 0; /* All 9 GPIOs are out */
}
static int rb4xx_gpio_direction_input(struct gpio_chip *chip,
unsigned int offset)
{
return -EOPNOTSUPP;
}
static int rb4xx_gpio_direction_output(struct gpio_chip *chip,
unsigned int offset, int value)
{
return rb4xx_gpio_cpld_set(gpiochip_get_data(chip), offset, value);
}
static int rb4xx_gpio_get(struct gpio_chip *chip, unsigned int offset)
{
struct rb4xx_gpio *gpio = gpiochip_get_data(chip);
int ret;
mutex_lock(&gpio->lock);
ret = (gpio->values >> offset) & 0x1;
mutex_unlock(&gpio->lock);
return ret;
}
static void rb4xx_gpio_set(struct gpio_chip *chip, unsigned int offset,
int value)
{
rb4xx_gpio_cpld_set(gpiochip_get_data(chip), offset, value);
}
static int rb4xx_gpio_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct device *parent = dev->parent;
struct rb4xx_gpio *gpio;
u32 val;
if (!parent)
return -ENODEV;
gpio = devm_kzalloc(dev, sizeof(*gpio), GFP_KERNEL);
if (!gpio)
return -ENOMEM;
platform_set_drvdata(pdev, gpio);
gpio->cpld = dev_get_drvdata(parent);
gpio->dev = dev;
gpio->values = 0;
mutex_init(&gpio->lock);
gpio->chip.label = "rb4xx-gpio";
gpio->chip.parent = dev;
gpio->chip.owner = THIS_MODULE;
gpio->chip.get_direction = rb4xx_gpio_get_direction;
gpio->chip.direction_input = rb4xx_gpio_direction_input;
gpio->chip.direction_output = rb4xx_gpio_direction_output;
gpio->chip.get = rb4xx_gpio_get;
gpio->chip.set = rb4xx_gpio_set;
gpio->chip.ngpio = 9;
gpio->chip.base = -1;
gpio->chip.can_sleep = 1;
if (!of_property_read_u32(dev->of_node, "base", &val))
gpio->chip.base = val;
return gpiochip_add_data(&gpio->chip, gpio);
}
static int rb4xx_gpio_remove(struct platform_device *pdev)
{
struct rb4xx_gpio *gpio = platform_get_drvdata(pdev);
gpiochip_remove(&gpio->chip);
mutex_destroy(&gpio->lock);
return 0;
}
static const struct platform_device_id rb4xx_gpio_id_table[] = {
{ "mikrotik,rb4xx-gpio", },
{ },
};
MODULE_DEVICE_TABLE(platform, rb4xx_gpio_id_table);
static struct platform_driver rb4xx_gpio_driver = {
.probe = rb4xx_gpio_probe,
.remove = rb4xx_gpio_remove,
.id_table = rb4xx_gpio_id_table,
.driver = {
.name = "rb4xx-gpio",
},
};
module_platform_driver(rb4xx_gpio_driver);
MODULE_DESCRIPTION("Mikrotik RB4xx GPIO driver");
MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
MODULE_AUTHOR("Imre Kaloz <kaloz@openwrt.org>");
MODULE_AUTHOR("Bert Vermeulen <bert@biot.com>");
MODULE_AUTHOR("Christopher Hill <ch6574@gmail.com");
MODULE_LICENSE("GPL v2");
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