mirror of https://gitee.com/openkylin/linux.git
115 lines
2.7 KiB
C
115 lines
2.7 KiB
C
|
/*
|
||
|
|
* GPIO-controlled multiplexer driver
|
||
|
|
*
|
||
|
|
* Copyright (C) 2017 Axentia Technologies AB
|
||
|
|
*
|
||
|
|
* Author: Peter Rosin <peda@axentia.se>
|
||
|
|
*
|
||
|
|
* This program is free software; you can redistribute it and/or modify
|
||
|
|
* it under the terms of the GNU General Public License version 2 as
|
||
|
|
* published by the Free Software Foundation.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include <linux/err.h>
|
||
|
|
#include <linux/gpio/consumer.h>
|
||
|
|
#include <linux/module.h>
|
||
|
|
#include <linux/mux/driver.h>
|
||
|
|
#include <linux/of_platform.h>
|
||
|
|
#include <linux/platform_device.h>
|
||
|
|
#include <linux/property.h>
|
||
|
|
|
||
|
|
struct mux_gpio {
|
||
|
|
struct gpio_descs *gpios;
|
||
|
|
int *val;
|
||
|
|
};
|
||
|
|
|
||
|
|
static int mux_gpio_set(struct mux_control *mux, int state)
|
||
|
|
{
|
||
|
|
struct mux_gpio *mux_gpio = mux_chip_priv(mux->chip);
|
||
|
|
int i;
|
||
|
|
|
||
|
|
for (i = 0; i < mux_gpio->gpios->ndescs; i++)
|
||
|
|
mux_gpio->val[i] = (state >> i) & 1;
|
||
|
|
|
||
|
|
gpiod_set_array_value_cansleep(mux_gpio->gpios->ndescs,
|
||
|
|
mux_gpio->gpios->desc,
|
||
|
|
mux_gpio->val);
|
||
|
|
|
||
|
|
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) +
|
||
|
|
pins * sizeof(*mux_gpio->val));
|
||
|
|
if (IS_ERR(mux_chip))
|
||
|
|
return PTR_ERR(mux_chip);
|
||
|
|
|
||
|
|
mux_gpio = mux_chip_priv(mux_chip);
|
||
|
|
mux_gpio->val = (int *)(mux_gpio + 1);
|
||
|
|
mux_chip->ops = &mux_gpio_ops;
|
||
|
|
|
||
|
|
mux_gpio->gpios = devm_gpiod_get_array(dev, "mux", GPIOD_OUT_LOW);
|
||
|
|
if (IS_ERR(mux_gpio->gpios)) {
|
||
|
|
ret = PTR_ERR(mux_gpio->gpios);
|
||
|
|
if (ret != -EPROBE_DEFER)
|
||
|
|
dev_err(dev, "failed to get gpios\n");
|
||
|
|
return ret;
|
||
|
|
}
|
||
|
|
WARN_ON(pins != mux_gpio->gpios->ndescs);
|
||
|
|
mux_chip->mux->states = 1 << 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 = of_match_ptr(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");
|