AV_CONF register (RH & TEMP. oversampling ratio's) and CTRL1 register (ODR & BDU settings) values are lost after suspend.
While the change in AV_CONF updates the sensor resolution modes (overriding the user configuration before the device went to suspend); loss of the contents of the CTRL1 register leads to failure in reading sensor output. This patch restores the AV_CONF & CTRL1 registers after resume. Changes from v1: - Don't drop enabling the sensor during resume - Restore AV_CONF register along with CTRL1 (As demonstrated with i2c register dumps of hts221 captured on Dell IoT Gateways 300x before suspend & after resume [1]) Fixes: ffebe74b7c95 (iio: humidity: hts221: avoid useless ODR reconfiguration) Signed-off-by: Shrirang Bagul <[email protected]> [v1] https://marc.info/?l=linux-iio&m=152506543000442&w=2 [1] https://marc.info/?l=linux-iio&m=152534455701742&w=2 This patch is based on: git://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio.git -b testing --- drivers/iio/humidity/hts221_core.c | 31 +++++++++++++++++++++++++++++- 1 file changed, 30 insertions(+), 1 deletion(-) diff --git a/drivers/iio/humidity/hts221_core.c b/drivers/iio/humidity/hts221_core.c index 166946d4978d..fc5599497f55 100644 --- a/drivers/iio/humidity/hts221_core.c +++ b/drivers/iio/humidity/hts221_core.c @@ -656,14 +656,43 @@ static int __maybe_unused hts221_resume(struct device *dev) { struct iio_dev *iio_dev = dev_get_drvdata(dev); struct hts221_hw *hw = iio_priv(iio_dev); + const struct hts221_avg *avg; + u8 data, idx; int err = 0; + /* Restore contents of AV_CONF (RH & TEMP. oversampling ratio's) */ + avg = &hts221_avg_list[HTS221_SENSOR_H]; + idx = hw->sensors[HTS221_SENSOR_H].cur_avg_idx; + data = avg->avg_avl[idx]; + err = hts221_update_avg(hw, HTS221_SENSOR_H, data); + if (err < 0) + goto fail_err; + + avg = &hts221_avg_list[HTS221_SENSOR_T]; + idx = hw->sensors[HTS221_SENSOR_T].cur_avg_idx; + data = avg->avg_avl[idx]; + err = hts221_update_avg(hw, HTS221_SENSOR_T, data); + if (err < 0) + goto fail_err; + + /* Restore contents of CTRL1 (BDU & ODR) */ + err = regmap_update_bits(hw->regmap, HTS221_REG_CNTRL1_ADDR, + HTS221_BDU_MASK, + FIELD_PREP(HTS221_BDU_MASK, 1)); + if (err < 0) + goto fail_err; + + err = hts221_update_odr(hw, hw->odr); + if (err < 0) + goto fail_err; + if (hw->enabled) err = regmap_update_bits(hw->regmap, HTS221_REG_CNTRL1_ADDR, HTS221_ENABLE_MASK, FIELD_PREP(HTS221_ENABLE_MASK, true)); - return err; +fail_err: + return err < 0 ? err : 0; } const struct dev_pm_ops hts221_pm_ops = { -- 2.17.1
