From: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
To: Shrirang Bagul <shrirang.bagul@canonical.com>
Cc: jic23@kernel.org, lorenzo.bianconi83@gmail.com,
linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org,
mario.tesi@st.com, marco.bianco@st.com, armando.visconti@st.com
Subject: Re: [PATCH v2] iio: humidity: hts221: Fix sensor reads after resume
Date: Thu, 28 Jun 2018 11:05:26 +0200 [thread overview]
Message-ID: <20180628090525.GA2540@localhost.localdomain> (raw)
In-Reply-To: <20180628082215.12023-1-shrirang.bagul@canonical.com>
> 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.
>
Hi Shrirang,
I still suspect we have some hw issue (IoT Gateway) here (cc ST folks
to get more info) and anyway I guess the proposed patch will fix the issue
completely since OD and HL configuration is not restored properly.
Could you please double check HL/OD regs are properly preserved after resume
phase?
Regards,
Lorenzo
> 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 <shrirang.bagul@canonical.com>
>
> [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;
just return err, no need for goto statement
> +
> + /* 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;
> +
just return err, no need for goto statement
> 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
>
next prev parent reply other threads:[~2018-06-28 9:05 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-28 8:22 [PATCH v2] iio: humidity: hts221: Fix sensor reads after resume Shrirang Bagul
2018-06-28 9:05 ` Lorenzo Bianconi [this message]
2018-07-01 4:37 ` Shrirang Bagul
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