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.tir...@intel.com>
> Reviewed-by: Vlad Dogaru <vlad.dog...@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[] = {
> 

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