Re: [PATCH v2 08/10] iio: accel: mma9551: Add runtime pm support

[Jonathan Cameron <jic23@kernel.org>]

On 11/01/15 19:10, Irina Tirdea wrote:
> Add support for runtime pm to reduce the power consumed by the device
> when not used.
> 
> If CONFIG_PM is not enabled, the device will be powered on at
> init and only powered off on system suspend.
> 
> If CONFIG_PM is enabled, runtime pm autosuspend is used:
> - for raw reads will keep the device on for a specified time
> - for events it will keep the device on as long as we have at least
> one event active
> 
> Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
> Reviewed-by: Vlad Dogaru <vlad.dogaru@intel.com>
Looks good.

Applied to the togreg branch of iio.git
(at least we are driving down the size of the patch set for the next
revision!)

Jonathan
> ---
>  drivers/iio/accel/mma9551.c | 162 +++++++++++++++++++++++++++++++++++++-------
>  1 file changed, 139 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/iio/accel/mma9551.c b/drivers/iio/accel/mma9551.c
> index 6563e26..f1a5a06 100644
> --- a/drivers/iio/accel/mma9551.c
> +++ b/drivers/iio/accel/mma9551.c
> @@ -22,6 +22,7 @@
>  #include <linux/iio/iio.h>
>  #include <linux/iio/sysfs.h>
>  #include <linux/iio/events.h>
> +#include <linux/pm_runtime.h>
>  
>  #define MMA9551_DRV_NAME		"mma9551"
>  #define MMA9551_IRQ_NAME		"mma9551_event"
> @@ -71,6 +72,7 @@ enum mma9551_gpio_pin {
>  /* Sleep/Wake application */
>  #define MMA9551_SLEEP_CFG		0x06
>  #define MMA9551_SLEEP_CFG_SNCEN		BIT(0)
> +#define MMA9551_SLEEP_CFG_FLEEN		BIT(1)
>  #define MMA9551_SLEEP_CFG_SCHEN		BIT(2)
>  
>  /* AFE application */
> @@ -114,6 +116,9 @@ enum mma9551_tilt_axis {
>  #define MMA9551_I2C_READ_RETRIES	5
>  #define MMA9551_I2C_READ_DELAY	50	/* us */
>  
> +#define MMA9551_DEFAULT_SAMPLE_RATE	122	/* Hz */
> +#define MMA9551_AUTO_SUSPEND_DELAY_MS	2000
> +
>  struct mma9551_mbox_request {
>  	u8 start_mbox;		/* Always 0. */
>  	u8 app_id;
> @@ -387,16 +392,55 @@ static int mma9551_read_version(struct i2c_client *client)
>  }
>  
>  /*
> + * Power on chip and enable doze mode.
>   * Use 'false' as the second parameter to cause the device to enter
>   * sleep.
>   */
> -static int mma9551_set_device_state(struct i2c_client *client,
> -				    bool enable)
> +static int mma9551_set_device_state(struct i2c_client *client, bool enable)
>  {
>  	return mma9551_update_config_bits(client, MMA9551_APPID_SLEEP_WAKE,
>  					  MMA9551_SLEEP_CFG,
> -					  MMA9551_SLEEP_CFG_SNCEN,
> -					  enable ? 0 : MMA9551_SLEEP_CFG_SNCEN);
> +					  MMA9551_SLEEP_CFG_SNCEN |
> +					  MMA9551_SLEEP_CFG_FLEEN |
> +					  MMA9551_SLEEP_CFG_SCHEN,
> +					  enable ? MMA9551_SLEEP_CFG_SCHEN |
> +					  MMA9551_SLEEP_CFG_FLEEN :
> +					  MMA9551_SLEEP_CFG_SNCEN);
> +}
> +
> +static int mma9551_set_power_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 void mma9551_sleep(int freq)
> +{
> +	int sleep_val = 1000 / freq;
> +
> +	if (sleep_val < 20)
> +		usleep_range(sleep_val * 1000, 20000);
> +	else
> +		msleep_interruptible(sleep_val);
>  }
>  
>  static int mma9551_read_incli_chan(struct i2c_client *client,
> @@ -424,15 +468,19 @@ static int mma9551_read_incli_chan(struct i2c_client *client,
>  		return -EINVAL;
>  	}
>  
> +	ret = mma9551_set_power_state(client, true);
> +	if (ret < 0)
> +		return ret;
> +
>  	ret = mma9551_read_status_byte(client, MMA9551_APPID_TILT,
>  				       reg_addr, &angle);
>  	if (ret < 0)
> -		return ret;
> +		goto out_poweroff;
>  
>  	ret = mma9551_read_status_byte(client, MMA9551_APPID_TILT,
>  				       MMA9551_TILT_QUAD_REG, &quadrant);
>  	if (ret < 0)
> -		return ret;
> +		goto out_poweroff;
>  
>  	angle &= ~MMA9551_TILT_ANGFLG;
>  	quadrant = (quadrant >> quad_shift) & 0x03;
> @@ -442,7 +490,11 @@ static int mma9551_read_incli_chan(struct i2c_client *client,
>  	else
>  		*val = angle + 90 * quadrant;
>  
> -	return IIO_VAL_INT;
> +	ret = IIO_VAL_INT;
> +
> +out_poweroff:
> +	mma9551_set_power_state(client, false);
> +	return ret;
>  }
>  
>  static int mma9551_read_accel_chan(struct i2c_client *client,
> @@ -467,14 +519,22 @@ static int mma9551_read_accel_chan(struct i2c_client *client,
>  		return -EINVAL;
>  	}
>  
> +	ret = mma9551_set_power_state(client, true);
> +	if (ret < 0)
> +		return ret;
> +
>  	ret = mma9551_read_status_word(client, MMA9551_APPID_AFE,
>  				       reg_addr, &raw_accel);
>  	if (ret < 0)
> -		return ret;
> +		goto out_poweroff;
>  
>  	*val = raw_accel;
>  
> -	return IIO_VAL_INT;
> +	ret = IIO_VAL_INT;
> +
> +out_poweroff:
> +	mma9551_set_power_state(client, false);
> +	return ret;
>  }
>  
>  static int mma9551_read_raw(struct iio_dev *indio_dev,
> @@ -556,6 +616,10 @@ static int mma9551_config_incli_event(struct iio_dev *indio_dev,
>  					  MMA9551_APPID_NONE, 0, 0);
>  		if (ret < 0)
>  			return ret;
> +
> +		ret = mma9551_set_power_state(data->client, false);
> +		if (ret < 0)
> +			return ret;
>  	} else {
>  		int bitnum;
>  
> @@ -574,11 +638,18 @@ static int mma9551_config_incli_event(struct iio_dev *indio_dev,
>  			return -EINVAL;
>  		}
>  
> +
Trivial but one blank line here is enough...
> +		ret = mma9551_set_power_state(data->client, true);
> +		if (ret < 0)
> +			return ret;
> +
>  		ret = mma9551_gpio_config(data->client,
>  					  (enum mma9551_gpio_pin)mma_axis,
>  					  MMA9551_APPID_TILT, bitnum, 0);
> -		if (ret < 0)
> +		if (ret < 0) {
> +			mma9551_set_power_state(data->client, false);
>  			return ret;
> +		}
>  	}
>  
>  	data->event_enabled[mma_axis] = state;
> @@ -771,12 +842,7 @@ static int mma9551_init(struct mma9551_data *data)
>  	if (ret)
>  		return ret;
>  
> -	/* Power on chip and enable doze mode. */
> -	return mma9551_update_config_bits(data->client,
> -			 MMA9551_APPID_SLEEP_WAKE,
> -			 MMA9551_SLEEP_CFG,
> -			 MMA9551_SLEEP_CFG_SCHEN | MMA9551_SLEEP_CFG_SNCEN,
> -			 MMA9551_SLEEP_CFG_SCHEN);
> +	return mma9551_set_device_state(data->client, true);
>  }
>  
>  static int mma9551_gpio_probe(struct iio_dev *indio_dev)
> @@ -869,8 +935,19 @@ static int mma9551_probe(struct i2c_client *client,
>  		goto out_poweroff;
>  	}
>  
> +	ret = pm_runtime_set_active(&client->dev);
> +	if (ret < 0)
> +		goto out_iio_unregister;
> +
> +	pm_runtime_enable(&client->dev);
> +	pm_runtime_set_autosuspend_delay(&client->dev,
> +					 MMA9551_AUTO_SUSPEND_DELAY_MS);
> +	pm_runtime_use_autosuspend(&client->dev);
> +
>  	return 0;
>  
> +out_iio_unregister:
> +	iio_device_unregister(indio_dev);
>  out_poweroff:
>  	mma9551_set_device_state(client, false);
>  
> @@ -882,6 +959,10 @@ static int mma9551_remove(struct i2c_client *client)
>  	struct iio_dev *indio_dev = i2c_get_clientdata(client);
>  	struct mma9551_data *data = iio_priv(indio_dev);
>  
> +	pm_runtime_disable(&client->dev);
> +	pm_runtime_set_suspended(&client->dev);
> +	pm_runtime_put_noidle(&client->dev);
> +
>  	iio_device_unregister(indio_dev);
>  	mutex_lock(&data->mutex);
>  	mma9551_set_device_state(data->client, false);
> @@ -890,37 +971,72 @@ static int mma9551_remove(struct i2c_client *client)
>  	return 0;
>  }
>  
> +#ifdef CONFIG_PM
> +static int mma9551_runtime_suspend(struct device *dev)
> +{
> +	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
> +	struct mma9551_data *data = iio_priv(indio_dev);
> +	int ret;
> +
> +	mutex_lock(&data->mutex);
> +	ret = mma9551_set_device_state(data->client, false);
> +	mutex_unlock(&data->mutex);
> +	if (ret < 0) {
> +		dev_err(&data->client->dev, "powering off device failed\n");
> +		return -EAGAIN;
> +	}
> +
> +	return 0;
> +}
> +
> +static int mma9551_runtime_resume(struct device *dev)
> +{
> +	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
> +	struct mma9551_data *data = iio_priv(indio_dev);
> +	int ret;
> +
> +	ret = mma9551_set_device_state(data->client, true);
> +	if (ret < 0)
> +		return ret;
> +
> +	mma9551_sleep(MMA9551_DEFAULT_SAMPLE_RATE);
> +
> +	return 0;
> +}
> +#endif
> +
>  #ifdef CONFIG_PM_SLEEP
>  static int mma9551_suspend(struct device *dev)
>  {
>  	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
>  	struct mma9551_data *data = iio_priv(indio_dev);
> +	int ret;
>  
>  	mutex_lock(&data->mutex);
> -	mma9551_set_device_state(data->client, false);
> +	ret = mma9551_set_device_state(data->client, false);
>  	mutex_unlock(&data->mutex);
>  
> -	return 0;
> +	return ret;
>  }
>  
>  static int mma9551_resume(struct device *dev)
>  {
>  	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
>  	struct mma9551_data *data = iio_priv(indio_dev);
> +	int ret;
>  
>  	mutex_lock(&data->mutex);
> -	mma9551_set_device_state(data->client, true);
> +	ret = mma9551_set_device_state(data->client, true);
>  	mutex_unlock(&data->mutex);
>  
> -	return 0;
> +	return ret;
>  }
> -#else
> -#define mma9551_suspend NULL
> -#define mma9551_resume NULL
>  #endif
>  
>  static const struct dev_pm_ops mma9551_pm_ops = {
>  	SET_SYSTEM_SLEEP_PM_OPS(mma9551_suspend, mma9551_resume)
> +	SET_RUNTIME_PM_OPS(mma9551_runtime_suspend,
> +			   mma9551_runtime_resume, NULL)
>  };
>  
>  static const struct acpi_device_id mma9551_acpi_match[] = {
>