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

Lorenzo Bianconi
2019-06-15T08:31:06Z

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> 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
>

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