Re: [PATCH v4 1/1] iio: pulsedlight-lidar-lite: add runtime PM

[Adriana Reus <adriana.reus-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>]

On 08.11.2015 22:26, Matt Ranostay wrote:
> Add runtime PM support for the lidar-lite module to enable low power
> mode when last device requested reading is over a second.
>
> Signed-off-by: Matt Ranostay <mranostay-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> ---
>   drivers/iio/proximity/pulsedlight-lidar-lite-v2.c | 54 ++++++++++++++++++++++-
>   1 file changed, 53 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/iio/proximity/pulsedlight-lidar-lite-v2.c b/drivers/iio/proximity/pulsedlight-lidar-lite-v2.c
> index 961f9f99..1a5481f 100644
> --- a/drivers/iio/proximity/pulsedlight-lidar-lite-v2.c
> +++ b/drivers/iio/proximity/pulsedlight-lidar-lite-v2.c
> @@ -13,7 +13,7 @@
>    * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
>    * GNU General Public License for more details.
>    *
> - * TODO: runtime pm, interrupt mode, and signal strength reporting
> + * TODO: interrupt mode, and signal strength reporting
>    */
>
>   #include <linux/err.h>
> @@ -21,6 +21,7 @@
>   #include <linux/i2c.h>
>   #include <linux/delay.h>
>   #include <linux/module.h>
> +#include <linux/pm_runtime.h>
>   #include <linux/iio/iio.h>
>   #include <linux/iio/sysfs.h>
>   #include <linux/iio/buffer.h>
> @@ -37,6 +38,7 @@
>
>   #define LIDAR_REG_DATA_HBYTE	0x0f
>   #define LIDAR_REG_DATA_LBYTE	0x10
> +#define LIDAR_REG_PWR_CONTROL	0x65
>
>   #define LIDAR_DRV_NAME "lidar"
>
> @@ -90,6 +92,12 @@ static inline int lidar_write_control(struct lidar_data *data, int val)
>   	return i2c_smbus_write_byte_data(data->client, LIDAR_REG_CONTROL, val);
>   }
>
> +static inline int lidar_write_power(struct lidar_data *data, int val)
> +{
> +	return i2c_smbus_write_byte_data(data->client,
> +					 LIDAR_REG_PWR_CONTROL, val);
> +}
> +
>   static int lidar_read_measurement(struct lidar_data *data, u16 *reg)
>   {
>   	int ret;
> @@ -116,6 +124,8 @@ static int lidar_get_measurement(struct lidar_data *data, u16 *reg)
>   	int tries = 10;
>   	int ret;
>
> +	pm_runtime_get_sync(&client->dev);
> +
>   	/* start sample */
>   	ret = lidar_write_control(data, LIDAR_REG_CONTROL_ACQUIRE);
>   	if (ret < 0) {
> @@ -144,6 +154,8 @@ static int lidar_get_measurement(struct lidar_data *data, u16 *reg)
>   		}
>   		ret = -EIO;
>   	}
> +	pm_runtime_mark_last_busy(&client->dev);
> +	pm_runtime_put_autosuspend(&client->dev);
>
>   	return ret;
>   }
> @@ -243,6 +255,15 @@ static int lidar_probe(struct i2c_client *client,
>   	if (ret)
>   		goto error_unreg_buffer;
>
> +	pm_runtime_set_autosuspend_delay(&client->dev, 1000);
> +	pm_runtime_use_autosuspend(&client->dev);
> +
> +	pm_runtime_set_active(&client->dev);
pm_runtime_set_active ^ may return an error code.
> +	pm_runtime_enable(&client->dev);
> +
> +	pm_runtime_mark_last_busy(&client->dev);
> +	pm_runtime_idle(&client->dev);
> +
>   	return 0;
>
>   error_unreg_buffer:
> @@ -258,6 +279,9 @@ static int lidar_remove(struct i2c_client *client)
>   	iio_device_unregister(indio_dev);
>   	iio_triggered_buffer_cleanup(indio_dev);
>
> +	pm_runtime_disable(&client->dev);
> +	pm_runtime_set_suspended(&client->dev);
> +
>   	return 0;
>   }
>
> @@ -273,10 +297,38 @@ static const struct of_device_id lidar_dt_ids[] = {
>   };
>   MODULE_DEVICE_TABLE(of, lidar_dt_ids);
>
> +#ifdef CONFIG_PM
> +static int lidar_pm_runtime_suspend(struct device *dev)
> +{
> +	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
> +	struct lidar_data *data = iio_priv(indio_dev);
> +
> +	return lidar_write_power(data, 0x0f);
> +}
> +
> +static int lidar_pm_runtime_resume(struct device *dev)
> +{
> +	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
> +	struct lidar_data *data = iio_priv(indio_dev);
> +	int ret = lidar_write_power(data, 0);
> +
> +	/* regulator and FPGA needs settling time */
> +	usleep_range(15000, 20000);
> +
> +	return ret;
> +}
> +#endif
> +
> +static const struct dev_pm_ops lidar_pm_ops = {
> +	SET_RUNTIME_PM_OPS(lidar_pm_runtime_suspend,
> +			   lidar_pm_runtime_resume, NULL)
> +};
> +
>   static struct i2c_driver lidar_driver = {
>   	.driver = {
>   		.name	= LIDAR_DRV_NAME,
>   		.of_match_table	= of_match_ptr(lidar_dt_ids),
> +		.pm	= &lidar_pm_ops,
>   	},
>   	.probe		= lidar_probe,
>   	.remove		= lidar_remove,
>