2015-11-07 14:37 GMT+09:00 Matt Ranostay <mranostay@xxxxxxxxx>:
> Add runtime PM support for the lidar-lite module to enable low power
> mode when last device requested reading is over a second ago.
>
> Signed-off-by: Matt Ranostay <mranostay@xxxxxxxxx>
> ---
> 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 e544fcf..e015a89 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;
> @@ -114,8 +122,15 @@ static int lidar_get_measurement(struct lidar_data *data, u16 *reg)
> {
> struct i2c_client *client = data->client;
> int tries = 10;
> + int suspended = pm_runtime_suspended(&client->dev);
> int ret;
>
That's racy. You have a gap here between check of the status, resuming
the device and actual use of the status.
> + pm_runtime_get(&client->dev);
Are you sure you want to use pm_runtime_get()? The async method? You
won't have any kind of certainty that resume really finished, even
after the usleep().
> +
> + /* regulator and FPGA needs settling time */
> + if (suspended)
> + usleep_range(15000, 20000);
> +
> /* start sample */
> ret = lidar_write_control(data, LIDAR_REG_CONTROL_ACQUIRE);
> if (ret < 0) {
> @@ -144,6 +159,7 @@ static int lidar_get_measurement(struct lidar_data *data, u16 *reg)
> }
> ret = -EIO;
> }
> + pm_runtime_put_autosuspend(&client->dev);
mark last busy?
Best regards,
Krzysztof
--
To unsubscribe from this list: send the line "unsubscribe linux-iio" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
