From: Artur Rojek <contact@artur-rojek.eu>
To: Paul Cercueil <paul@crapouillou.net>
Cc: Jonathan Cameron <jic23@kernel.org>,
Lars-Peter Clausen <lars@metafoo.de>,
Peter Meerwald-Stadler <pmeerw@pmeerw.net>,
od@zcrc.me, linux-iio@vger.kernel.org,
linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH] iio/adc: ingenic: Fix AUX/VBAT readings when touchscreen is used
Date: Wed, 04 Nov 2020 23:25:12 +0100 [thread overview]
Message-ID: <bbd87ebab678e3033545fef749c3b22a@artur-rojek.eu> (raw)
In-Reply-To: <20201103201238.161083-1-paul@crapouillou.net>
Hi Paul,
On 2020-11-03 21:12, Paul Cercueil wrote:
> When the command feature of the ADC is used, it is possible to program
> the ADC, and specify at each step what input should be processed, and
> in
> comparison to what reference.
>
> This broke the AUX and battery readings when the touchscreen was
> enabled, most likely because the CMD feature would change the VREF all
> the time.
>
> Now, when AUX or battery are read, we temporarily disable the CMD
> feature, which means that we won't get touchscreen readings in that
> time
> frame. But it now gives correct values for AUX / battery, and the
> touchscreen isn't disabled for long enough to be an actual issue.
>
> Fixes: b96952f498db ("IIO: Ingenic JZ47xx: Add touchscreen mode.")
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Paul Cercueil <paul@crapouillou.net>
> ---
> drivers/iio/adc/ingenic-adc.c | 33 +++++++++++++++++++++++++++------
> 1 file changed, 27 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/iio/adc/ingenic-adc.c
> b/drivers/iio/adc/ingenic-adc.c
> index 92b25083e23f..ecaff6a9b716 100644
> --- a/drivers/iio/adc/ingenic-adc.c
> +++ b/drivers/iio/adc/ingenic-adc.c
> @@ -177,13 +177,12 @@ static void ingenic_adc_set_config(struct
> ingenic_adc *adc,
> mutex_unlock(&adc->lock);
> }
>
> -static void ingenic_adc_enable(struct ingenic_adc *adc,
> - int engine,
> - bool enabled)
> +static void ingenic_adc_enable_unlocked(struct ingenic_adc *adc,
> + int engine,
> + bool enabled)
> {
> u8 val;
>
> - mutex_lock(&adc->lock);
> val = readb(adc->base + JZ_ADC_REG_ENABLE);
>
> if (enabled)
> @@ -192,20 +191,42 @@ static void ingenic_adc_enable(struct ingenic_adc
> *adc,
> val &= ~BIT(engine);
>
> writeb(val, adc->base + JZ_ADC_REG_ENABLE);
> +}
> +
> +static void ingenic_adc_enable(struct ingenic_adc *adc,
> + int engine,
> + bool enabled)
> +{
> + mutex_lock(&adc->lock);
> + ingenic_adc_enable_unlocked(adc, engine, enabled);
> mutex_unlock(&adc->lock);
> }
>
> static int ingenic_adc_capture(struct ingenic_adc *adc,
> int engine)
> {
> + u32 cfg;
> u8 val;
> int ret;
>
> - ingenic_adc_enable(adc, engine, true);
> + /*
> + * Disable CMD_SEL temporarily, because it causes wrong VBAT
> readings,
> + * probably due to the switch of VREF. We must keep the lock here to
> + * avoid races with the buffer enable/disable functions.
> + */
> + mutex_lock(&adc->lock);
> + cfg = readl(adc->base + JZ_ADC_REG_CFG);
> + writel(cfg & ~JZ_ADC_REG_CFG_CMD_SEL, adc->base + JZ_ADC_REG_CFG);
> +
> +
Redundant empty line.
> + ingenic_adc_enable_unlocked(adc, engine, true);
> ret = readb_poll_timeout(adc->base + JZ_ADC_REG_ENABLE, val,
> !(val & BIT(engine)), 250, 1000);
> if (ret)
> - ingenic_adc_enable(adc, engine, false);
> + ingenic_adc_enable_unlocked(adc, engine, false);
> +
> + writel(cfg, adc->base + JZ_ADC_REG_CFG);
> + mutex_unlock(&adc->lock);
>
> return ret;
> }
With the above nitpick corrected:
Acked-by: Artur Rojek <contact@artur-rojek.eu>
next prev parent reply other threads:[~2020-11-04 22:27 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-03 20:12 [PATCH] iio/adc: ingenic: Fix AUX/VBAT readings when touchscreen is used Paul Cercueil
2020-11-04 22:25 ` Artur Rojek [this message]
2020-11-08 15:37 ` Jonathan Cameron
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