Re: [RFC PATCH 1/3] iio: imu: st_lsm6dsx: add wake on accelerometer threshold

[Lorenzo Bianconi <lorenzo@kernel.org>]

[-- Attachment #1: Type: text/plain, Size: 6019 bytes --]

> Added wakeup-source option for waking on accelerometer events.
> If the wakeup-source is specified, we activate this on our
> way down to suspend. We start the accelerometer in
> low power mode and wait for it to report a wake event.
> 

Hi Sean,

thx for working on this, some comments inline.

Regards,
Lorenzo

> Signed-off-by: Sean Nyekjaer <sean@geanix.com>
> ---
>  drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h      |  2 +
>  drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c | 70 ++++++++++++++++++++
>  2 files changed, 72 insertions(+)
> 
> diff --git a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h
> index edcd838037cd..ef4327fd57d6 100644
> --- a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h
> +++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h
> @@ -147,6 +147,7 @@ struct st_lsm6dsx_hw {
>  	struct device *dev;
>  	struct regmap *regmap;
>  	int irq;
> +	bool irq_wake;
>  
>  	struct mutex fifo_lock;
>  	struct mutex conf_lock;
> @@ -155,6 +156,7 @@ struct st_lsm6dsx_hw {
>  	u8 enable_mask;
>  	u8 ts_sip;
>  	u8 sip;
> +	u8 wake_threshold;
>  
>  	u8 *buff;
>  
> diff --git a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c
> index aebbe0ddd8d8..092c4d02bd4e 100644
> --- a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c
> +++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c
> @@ -36,6 +36,7 @@
>  #include <linux/delay.h>
>  #include <linux/iio/iio.h>
>  #include <linux/iio/sysfs.h>
> +#include <linux/interrupt.h>
>  #include <linux/pm.h>
>  #include <linux/regmap.h>
>  #include <linux/bitfield.h>
> @@ -71,6 +72,17 @@
>  #define ST_LSM6DSX_REG_GYRO_OUT_Y_L_ADDR	0x24
>  #define ST_LSM6DSX_REG_GYRO_OUT_Z_L_ADDR	0x26
>  
> +#define ST_LSM6DSX_REG_TAP_CFG_ADDR		0x58
> +#define ST_LSM6DSX_REG_TAP_CFG_INT_EN_MASK	BIT(7)
> +#define ST_LSM6DSX_REG_TAP_CFG_INACT_EN_MASK	GENMASK(6, 5)
> +
> +#define ST_LSM6DSX_DEFAULT_WAKE_THRESH		0
> +#define ST_LSM6DSX_REG_WAKE_UP_THS_ADDR		0x5B
> +#define ST_LSM6DSX_REG_WAKE_UP_THS_THRES_MASK	GENMASK(5, 0)
> +
> +#define ST_LSM6DSX_REG_MD1_CFG_ADDR		0x5E
> +#define ST_LSM6DSX_REG_MD1_CFG_INT1_WU_MASK	BIT(5)
> +
>  #define ST_LSM6DSX_ACC_FS_2G_GAIN		IIO_G_TO_M_S_2(61)
>  #define ST_LSM6DSX_ACC_FS_4G_GAIN		IIO_G_TO_M_S_2(122)
>  #define ST_LSM6DSX_ACC_FS_8G_GAIN		IIO_G_TO_M_S_2(244)

have you verified these register maps is the same for all supported devices?

> @@ -428,6 +440,19 @@ static int st_lsm6dsx_set_odr(struct st_lsm6dsx_sensor *sensor, u16 odr)
>  				  ST_LSM6DSX_SHIFT_VAL(val, reg->mask));
>  }
>  
> +static int st_lsm6dsx_set_wake_threshold(struct st_lsm6dsx_hw *hw, u8 threshold)
> +{
> +	int err = 0;
> +
> +	err = regmap_update_bits(hw->regmap, ST_LSM6DSX_REG_WAKE_UP_THS_ADDR,
> +				 ST_LSM6DSX_REG_WAKE_UP_THS_THRES_MASK,
> +				 threshold);
> +	if (!err)
> +		hw->wake_threshold = threshold;
> +
> +	return err;
> +}

I guess you can move it in patch 3/3

> +
>  int st_lsm6dsx_sensor_enable(struct st_lsm6dsx_sensor *sensor)
>  {
>  	int err;
> @@ -754,6 +779,8 @@ static int st_lsm6dsx_init_device(struct st_lsm6dsx_hw *hw)
>  	if (err < 0)
>  		return err;
>  
> +	st_lsm6dsx_set_wake_threshold(hw, ST_LSM6DSX_DEFAULT_WAKE_THRESH);

we do not need this since default value is 0

> +
>  	return st_lsm6dsx_init_hw_timer(hw);
>  }
>  
> @@ -853,6 +880,10 @@ int st_lsm6dsx_probe(struct device *dev, int irq, int hw_id, const char *name,
>  			return err;
>  	}
>  
> +	if (dev->of_node)
> +		if (of_property_read_bool(dev->of_node, "wakeup-source"))
> +			device_init_wakeup(dev, true);
> +

you probably need to add the equivalent for the pdata case. Maybe it is better
a dedicated routine

>  	return 0;
>  }
>  EXPORT_SYMBOL(st_lsm6dsx_probe);
> @@ -879,6 +910,26 @@ static int __maybe_unused st_lsm6dsx_suspend(struct device *dev)
>  	if (hw->fifo_mode != ST_LSM6DSX_FIFO_BYPASS)
>  		err = st_lsm6dsx_flush_fifo(hw);
>  
> +	if (device_may_wakeup(dev)) {
> +		sensor = iio_priv(hw->iio_devs[ST_LSM6DSX_ID_ACC]);
> +		err = st_lsm6dsx_sensor_enable(sensor);

better not not disable the acc in this case

> +
> +		/* Enable inactivity function - low power ACC, GYRO powered-down */
> +		err = regmap_update_bits(hw->regmap, ST_LSM6DSX_REG_TAP_CFG_ADDR,
> +				ST_LSM6DSX_REG_TAP_CFG_INT_EN_MASK |
> +				ST_LSM6DSX_REG_TAP_CFG_INACT_EN_MASK,
> +				ST_LSM6DSX_REG_TAP_CFG_INT_EN_MASK |
> +				ST_LSM6DSX_REG_TAP_CFG_INACT_EN_MASK);
> +
> +		/* Enable wakeup interrupt */
> +		err = regmap_update_bits(hw->regmap, ST_LSM6DSX_REG_MD1_CFG_ADDR,
> +				ST_LSM6DSX_REG_MD1_CFG_INT1_WU_MASK,
> +				ST_LSM6DSX_REG_MD1_CFG_INT1_WU_MASK);

I guess we can enable it by default

> +
> +		/* Enable wake from IRQ */
> +		hw->irq_wake = (enable_irq_wake(hw->irq) == 0);

do we really need this? maybe it is enough to just disable
ST_LSM6DSX_REG_TAP_CFG_ADDR in st_lsm6dsx_resume and drop irq_wake

> +	}
> +
>  	return err;
>  }
>  
> @@ -888,6 +939,25 @@ static int __maybe_unused st_lsm6dsx_resume(struct device *dev)
>  	struct st_lsm6dsx_sensor *sensor;
>  	int i, err = 0;
>  
> +	if (device_may_wakeup(dev) && hw->irq_wake) {
> +		disable_irq_wake(hw->irq);
> +		hw->irq_wake = false;
> +
> +		sensor = iio_priv(hw->iio_devs[ST_LSM6DSX_ID_ACC]);
> +		err = st_lsm6dsx_sensor_disable(sensor);

I guess this breaks the acc/sensor hub resume

> +
> +		/* Disable inactivity function */
> +		err = regmap_update_bits(hw->regmap, ST_LSM6DSX_REG_TAP_CFG_ADDR,
> +				ST_LSM6DSX_REG_TAP_CFG_INT_EN_MASK |
> +				ST_LSM6DSX_REG_TAP_CFG_INACT_EN_MASK,
> +				0);
> +
> +		/* Disable wakeup interrupt */
> +		err = regmap_update_bits(hw->regmap, ST_LSM6DSX_REG_MD1_CFG_ADDR,
> +				ST_LSM6DSX_REG_MD1_CFG_INT1_WU_MASK,
> +				0);
> +	}
> +
>  	for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) {
>  		sensor = iio_priv(hw->iio_devs[i]);
>  		if (!(hw->enable_mask & BIT(sensor->id)))
> -- 
> 2.22.0
> 

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 228 bytes --]