Re: [PATCH] iio: imu: st_lsm6dsx: fix PM support for st_lsm6dsx i2c controller

[Jonathan Cameron <jic23@kernel.org>]

On Sun, 19 May 2019 10:58:23 +0200
Lorenzo Bianconi <lorenzo@kernel.org> wrote:

> Properly suspend/resume i2c slaves connected to st_lsm6dsx master
> controller if the CPU goes in suspended state
> 
> Fixes: c91c1c844ebd ("imu: st_lsm6dsx: add i2c embedded controller support")
> Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Applied to the fixes-togreg branch of iio.git and marked for stable.

Thanks,

Jonathan

> ---
>  drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h      |  2 ++
>  drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c | 25 +++++++++++++-------
>  2 files changed, 19 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h
> index 004a8a1a0027..6ef3577234a0 100644
> --- a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h
> +++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h
> @@ -271,6 +271,7 @@ struct st_lsm6dsx_sensor {
>   * @conf_lock: Mutex to prevent concurrent FIFO configuration update.
>   * @page_lock: Mutex to prevent concurrent memory page configuration.
>   * @fifo_mode: FIFO operating mode supported by the device.
> + * @suspend_mask: Suspended sensor bitmask.
>   * @enable_mask: Enabled sensor bitmask.
>   * @ts_sip: Total number of timestamp samples in a given pattern.
>   * @sip: Total number of samples (acc/gyro/ts) in a given pattern.
> @@ -288,6 +289,7 @@ struct st_lsm6dsx_hw {
>  	struct mutex page_lock;
>  
>  	enum st_lsm6dsx_fifo_mode fifo_mode;
> +	u8 suspend_mask;
>  	u8 enable_mask;
>  	u8 ts_sip;
>  	u8 sip;
> diff --git a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c
> index cf82c9049945..be5c87c8266d 100644
> --- a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c
> +++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c
> @@ -1110,8 +1110,6 @@ static int __maybe_unused st_lsm6dsx_suspend(struct device *dev)
>  {
>  	struct st_lsm6dsx_hw *hw = dev_get_drvdata(dev);
>  	struct st_lsm6dsx_sensor *sensor;
> -	const struct st_lsm6dsx_reg *reg;
> -	unsigned int data;
>  	int i, err = 0;
>  
>  	for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) {
> @@ -1122,12 +1120,16 @@ static int __maybe_unused st_lsm6dsx_suspend(struct device *dev)
>  		if (!(hw->enable_mask & BIT(sensor->id)))
>  			continue;
>  
> -		reg = &st_lsm6dsx_odr_table[sensor->id].reg;
> -		data = ST_LSM6DSX_SHIFT_VAL(0, reg->mask);
> -		err = st_lsm6dsx_update_bits_locked(hw, reg->addr, reg->mask,
> -						    data);
> +		if (sensor->id == ST_LSM6DSX_ID_EXT0 ||
> +		    sensor->id == ST_LSM6DSX_ID_EXT1 ||
> +		    sensor->id == ST_LSM6DSX_ID_EXT2)
> +			err = st_lsm6dsx_shub_set_enable(sensor, false);
> +		else
> +			err = st_lsm6dsx_sensor_set_enable(sensor, false);
>  		if (err < 0)
>  			return err;
> +
> +		hw->suspend_mask |= BIT(sensor->id);
>  	}
>  
>  	if (hw->fifo_mode != ST_LSM6DSX_FIFO_BYPASS)
> @@ -1147,12 +1149,19 @@ static int __maybe_unused st_lsm6dsx_resume(struct device *dev)
>  			continue;
>  
>  		sensor = iio_priv(hw->iio_devs[i]);
> -		if (!(hw->enable_mask & BIT(sensor->id)))
> +		if (!(hw->suspend_mask & BIT(sensor->id)))
>  			continue;
>  
> -		err = st_lsm6dsx_set_odr(sensor, sensor->odr);
> +		if (sensor->id == ST_LSM6DSX_ID_EXT0 ||
> +		    sensor->id == ST_LSM6DSX_ID_EXT1 ||
> +		    sensor->id == ST_LSM6DSX_ID_EXT2)
> +			err = st_lsm6dsx_shub_set_enable(sensor, true);
> +		else
> +			err = st_lsm6dsx_sensor_set_enable(sensor, true);
>  		if (err < 0)
>  			return err;
> +
> +		hw->suspend_mask &= ~BIT(sensor->id);
>  	}
>  
>  	if (hw->enable_mask)