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Commit 96c0cb2b authored by Martin Kepplinger's avatar Martin Kepplinger Committed by Jonathan Cameron
Browse files

iio: mma8452: add support for runtime power management 



This adds support for runtime power management and, if configured, activates
automatic standby after 2 seconds of inactivity.

Inactivity means no read of acceleration values and no events triggered or
activated.

If CONFIG_PM is not set, this doesn't change anything for existing users.

Signed-off-by: default avatarMartin Kepplinger <martink@posteo.de>
Signed-off-by: default avatarChristoph Muellner <christoph.muellner@theobroma-systems.com>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent e866853d

drivers/iio/accel/mma8452.c

+108 −10
Original line number Diff line number Diff line
@@ -31,6 +31,7 @@ 
#include <linux/delay.h>

#include <linux/of_device.h>

#include <linux/of_irq.h>

#include <linux/pm_runtime.h>



#define MMA8452_STATUS				0x00

#define  MMA8452_STATUS_DRDY			(BIT(2) | BIT(1) | BIT(0))
@@ -92,6 +93,8 @@ 
#define MMA8652_DEVICE_ID			0x4a

#define MMA8653_DEVICE_ID			0x5a



#define MMA8452_AUTO_SUSPEND_DELAY_MS		2000



struct mma8452_data {

	struct i2c_client *client;

	struct mutex lock;
@@ -172,6 +175,31 @@ static int mma8452_drdy(struct mma8452_data *data) 
	return -EIO;

}



static int mma8452_set_runtime_pm_state(struct i2c_client *client, bool on)

{

#ifdef CONFIG_PM

	int ret;



	if (on) {

		ret = pm_runtime_get_sync(&client->dev);

	} else {

		pm_runtime_mark_last_busy(&client->dev);

		ret = pm_runtime_put_autosuspend(&client->dev);

	}



	if (ret < 0) {

		dev_err(&client->dev,

			"failed to change power state to %d\n", on);

		if (on)

			pm_runtime_put_noidle(&client->dev);



		return ret;

	}

#endif



	return 0;

}



static int mma8452_read(struct mma8452_data *data, __be16 buf[3])

{

	int ret = mma8452_drdy(data);
@@ -179,8 +207,16 @@ static int mma8452_read(struct mma8452_data *data, __be16 buf[3]) 
	if (ret < 0)

		return ret;



	return i2c_smbus_read_i2c_block_data(data->client, MMA8452_OUT_X,

	ret = mma8452_set_runtime_pm_state(data->client, true);

	if (ret)

		return ret;



	ret = i2c_smbus_read_i2c_block_data(data->client, MMA8452_OUT_X,

					    3 * sizeof(__be16), (u8 *)buf);



	ret = mma8452_set_runtime_pm_state(data->client, false);



	return ret;

}



static ssize_t mma8452_show_int_plus_micros(char *buf, const int (*vals)[2],
@@ -707,7 +743,11 @@ static int mma8452_write_event_config(struct iio_dev *indio_dev, 
{

	struct mma8452_data *data = iio_priv(indio_dev);

	const struct mma_chip_info *chip = data->chip_info;

	int val;

	int val, ret;



	ret = mma8452_set_runtime_pm_state(data->client, state);

	if (ret)

		return ret;



	switch (dir) {

	case IIO_EV_DIR_FALLING:
@@ -1139,7 +1179,11 @@ static int mma8452_data_rdy_trigger_set_state(struct iio_trigger *trig, 
{

	struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);

	struct mma8452_data *data = iio_priv(indio_dev);

	int reg;

	int reg, ret;



	ret = mma8452_set_runtime_pm_state(data->client, state);

	if (ret)

		return ret;



	reg = i2c_smbus_read_byte_data(data->client, MMA8452_CTRL_REG4);

	if (reg < 0)
@@ -1365,6 +1409,15 @@ static int mma8452_probe(struct i2c_client *client, 
			goto buffer_cleanup;

	}



	ret = pm_runtime_set_active(&client->dev);

	if (ret < 0)

		goto buffer_cleanup;



	pm_runtime_enable(&client->dev);

	pm_runtime_set_autosuspend_delay(&client->dev,

					 MMA8452_AUTO_SUSPEND_DELAY_MS);

	pm_runtime_use_autosuspend(&client->dev);



	ret = iio_device_register(indio_dev);

	if (ret < 0)

		goto buffer_cleanup;
@@ -1389,6 +1442,11 @@ static int mma8452_remove(struct i2c_client *client) 
	struct iio_dev *indio_dev = i2c_get_clientdata(client);



	iio_device_unregister(indio_dev);



	pm_runtime_disable(&client->dev);

	pm_runtime_set_suspended(&client->dev);

	pm_runtime_put_noidle(&client->dev);



	iio_triggered_buffer_cleanup(indio_dev);

	mma8452_trigger_cleanup(indio_dev);

	mma8452_standby(iio_priv(indio_dev));
@@ -1396,6 +1454,45 @@ static int mma8452_remove(struct i2c_client *client) 
	return 0;

}



#ifdef CONFIG_PM

static int mma8452_runtime_suspend(struct device *dev)

{

	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));

	struct mma8452_data *data = iio_priv(indio_dev);

	int ret;



	mutex_lock(&data->lock);

	ret = mma8452_standby(data);

	mutex_unlock(&data->lock);

	if (ret < 0) {

		dev_err(&data->client->dev, "powering off device failed\n");

		return -EAGAIN;

	}



	return 0;

}



static int mma8452_runtime_resume(struct device *dev)

{

	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));

	struct mma8452_data *data = iio_priv(indio_dev);

	int ret, sleep_val;



	ret = mma8452_active(data);

	if (ret < 0)

		return ret;



	ret = mma8452_get_odr_index(data);

	sleep_val = 1000 / mma8452_samp_freq[ret][0];

	if (sleep_val < 20)

		usleep_range(sleep_val * 1000, 20000);

	else

		msleep_interruptible(sleep_val);



	return 0;

}

#endif



#ifdef CONFIG_PM_SLEEP

static int mma8452_suspend(struct device *dev)

{
@@ -1408,13 +1505,14 @@ static int mma8452_resume(struct device *dev) 
	return mma8452_active(iio_priv(i2c_get_clientdata(

		to_i2c_client(dev))));

}



static SIMPLE_DEV_PM_OPS(mma8452_pm_ops, mma8452_suspend, mma8452_resume);

#define MMA8452_PM_OPS (&mma8452_pm_ops)

#else

#define MMA8452_PM_OPS NULL

#endif



static const struct dev_pm_ops mma8452_pm_ops = {

	SET_SYSTEM_SLEEP_PM_OPS(mma8452_suspend, mma8452_resume)

	SET_RUNTIME_PM_OPS(mma8452_runtime_suspend,

			   mma8452_runtime_resume, NULL)

};



static const struct i2c_device_id mma8452_id[] = {

	{ "mma8452", mma8452 },

	{ "mma8453", mma8453 },
@@ -1428,7 +1526,7 @@ static struct i2c_driver mma8452_driver = { 
	.driver = {

		.name	= "mma8452",

		.of_match_table = of_match_ptr(mma8452_dt_ids),

		.pm	= MMA8452_PM_OPS,

		.pm	= &mma8452_pm_ops,

	},

	.probe = mma8452_probe,

	.remove = mma8452_remove,