src/kernel/linux/v4.19/drivers/iio/gyro/mpu3050-i2c.c

#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/i2c-mux.h>
#include <linux/iio/iio.h>
#include <linux/module.h>
#include <linux/regmap.h>
#include <linux/pm_runtime.h>

#include "mpu3050.h"

static const struct regmap_config mpu3050_i2c_regmap_config = {
	.reg_bits = 8,
	.val_bits = 8,
};

static int mpu3050_i2c_bypass_select(struct i2c_mux_core *mux, u32 chan_id)
{
	struct mpu3050 *mpu3050 = i2c_mux_priv(mux);

	/* Just power up the device, that is all that is needed */
	pm_runtime_get_sync(mpu3050->dev);
	return 0;
}

static int mpu3050_i2c_bypass_deselect(struct i2c_mux_core *mux, u32 chan_id)
{
	struct mpu3050 *mpu3050 = i2c_mux_priv(mux);

	pm_runtime_mark_last_busy(mpu3050->dev);
	pm_runtime_put_autosuspend(mpu3050->dev);
	return 0;
}

static int mpu3050_i2c_probe(struct i2c_client *client,
			     const struct i2c_device_id *id)
{
	struct regmap *regmap;
	const char *name;
	struct mpu3050 *mpu3050;
	int ret;

	if (!i2c_check_functionality(client->adapter,
				     I2C_FUNC_SMBUS_I2C_BLOCK))
		return -EOPNOTSUPP;

	if (id)
		name = id->name;
	else
		return -ENODEV;

	regmap = devm_regmap_init_i2c(client, &mpu3050_i2c_regmap_config);
	if (IS_ERR(regmap)) {
		dev_err(&client->dev, "Failed to register i2c regmap %d\n",
			(int)PTR_ERR(regmap));
		return PTR_ERR(regmap);
	}

	ret = mpu3050_common_probe(&client->dev, regmap, client->irq, name);
	if (ret)
		return ret;

	/* The main driver is up, now register the I2C mux */
	mpu3050 = iio_priv(dev_get_drvdata(&client->dev));
	mpu3050->i2cmux = i2c_mux_alloc(client->adapter, &client->dev,
					1, 0, I2C_MUX_LOCKED | I2C_MUX_GATE,
					mpu3050_i2c_bypass_select,
					mpu3050_i2c_bypass_deselect);
	/* Just fail the mux, there is no point in killing the driver */
	if (!mpu3050->i2cmux)
		dev_err(&client->dev, "failed to allocate I2C mux\n");
	else {
		mpu3050->i2cmux->priv = mpu3050;
		/* Ignore failure, not critical */
		i2c_mux_add_adapter(mpu3050->i2cmux, 0, 0, 0);
	}

	return 0;
}

static int mpu3050_i2c_remove(struct i2c_client *client)
{
	struct iio_dev *indio_dev = dev_get_drvdata(&client->dev);
	struct mpu3050 *mpu3050 = iio_priv(indio_dev);

	if (mpu3050->i2cmux)
		i2c_mux_del_adapters(mpu3050->i2cmux);

	return mpu3050_common_remove(&client->dev);
}

/*
 * device id table is used to identify what device can be
 * supported by this driver
 */
static const struct i2c_device_id mpu3050_i2c_id[] = {
	{ "mpu3050" },
	{}
};
MODULE_DEVICE_TABLE(i2c, mpu3050_i2c_id);

static const struct of_device_id mpu3050_i2c_of_match[] = {
	{ .compatible = "invensense,mpu3050", .data = "mpu3050" },
	/* Deprecated vendor ID from the Input driver */
	{ .compatible = "invn,mpu3050", .data = "mpu3050" },
	{ },
};
MODULE_DEVICE_TABLE(of, mpu3050_i2c_of_match);

static struct i2c_driver mpu3050_i2c_driver = {
	.probe = mpu3050_i2c_probe,
	.remove = mpu3050_i2c_remove,
	.id_table = mpu3050_i2c_id,
	.driver = {
		.of_match_table = mpu3050_i2c_of_match,
		.name = "mpu3050-i2c",
		.pm = &mpu3050_dev_pm_ops,
	},
};
module_i2c_driver(mpu3050_i2c_driver);

MODULE_AUTHOR("Linus Walleij");
MODULE_DESCRIPTION("Invensense MPU3050 gyroscope driver");
MODULE_LICENSE("GPL");