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// SPDX-License-Identifier: GPL-2.0
/*
* GPIO-controlled multiplexer driver
*
* Copyright (C) 2017 Axentia Technologies AB
*
* Author: Peter Rosin <peda@axentia.se>
*/
#include <linux/bitmap.h>
#include <linux/err.h>
#include <linux/gpio/consumer.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/mux/driver.h>
#include <linux/platform_device.h>
#include <linux/property.h>
struct mux_gpio {
struct gpio_descs *gpios;
};
static int mux_gpio_set(struct mux_control *mux, int state)
{
struct mux_gpio *mux_gpio = mux_chip_priv(mux->chip);
DECLARE_BITMAP(values, BITS_PER_TYPE(state));
u32 value = state;
bitmap_from_arr32(values, &value, BITS_PER_TYPE(value));
gpiod_set_array_value_cansleep(mux_gpio->gpios->ndescs,
mux_gpio->gpios->desc,
mux_gpio->gpios->info, values);
return 0;
}
static const struct mux_control_ops mux_gpio_ops = {
.set = mux_gpio_set,
};
static const struct of_device_id mux_gpio_dt_ids[] = {
{ .compatible = "gpio-mux", },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, mux_gpio_dt_ids);
static int mux_gpio_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct mux_chip *mux_chip;
struct mux_gpio *mux_gpio;
int pins;
s32 idle_state;
int ret;
pins = gpiod_count(dev, "mux");
if (pins < 0)
return pins;
mux_chip = devm_mux_chip_alloc(dev, 1, sizeof(*mux_gpio));
if (IS_ERR(mux_chip))
return PTR_ERR(mux_chip);
mux_gpio = mux_chip_priv(mux_chip);
mux_chip->ops = &mux_gpio_ops;
mux_gpio->gpios = devm_gpiod_get_array(dev, "mux", GPIOD_OUT_LOW);
if (IS_ERR(mux_gpio->gpios))
return dev_err_probe(dev, PTR_ERR(mux_gpio->gpios),
"failed to get gpios\n");
WARN_ON(pins != mux_gpio->gpios->ndescs);
mux_chip->mux->states = BIT(pins);
ret = device_property_read_u32(dev, "idle-state", (u32 *)&idle_state);
if (ret >= 0 && idle_state != MUX_IDLE_AS_IS) {
if (idle_state < 0 || idle_state >= mux_chip->mux->states) {
dev_err(dev, "invalid idle-state %u\n", idle_state);
return -EINVAL;
}
mux_chip->mux->idle_state = idle_state;
}
ret = devm_mux_chip_register(dev, mux_chip);
if (ret < 0)
return ret;
dev_info(dev, "%u-way mux-controller registered\n",
mux_chip->mux->states);
return 0;
}
static struct platform_driver mux_gpio_driver = {
.driver = {
.name = "gpio-mux",
.of_match_table = mux_gpio_dt_ids,
},
.probe = mux_gpio_probe,
};
module_platform_driver(mux_gpio_driver);
MODULE_DESCRIPTION("GPIO-controlled multiplexer driver");
MODULE_AUTHOR("Peter Rosin <peda@axentia.se>");
MODULE_LICENSE("GPL v2");
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