This is a note to let you know that I've just added the patch titled
iio/adc: ingenic: Fix AUX/VBAT readings when touchscreen is used
to my staging git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git in the staging-linus branch.
The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.
If you have any questions about this process, please let me know.
From 6d6aa2907d59ddd3c0ebb2b93e1ddc84e474485b Mon Sep 17 00:00:00 2001
From: Paul Cercueil paul@crapouillou.net Date: Tue, 3 Nov 2020 20:12:38 +0000 Subject: iio/adc: ingenic: Fix AUX/VBAT readings when touchscreen is used
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.") Signed-off-by: Paul Cercueil paul@crapouillou.net Acked-by: Artur Rojek contact@artur-rojek.eu Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20201103201238.161083-1-paul@crapouillou.net Signed-off-by: Jonathan Cameron Jonathan.Cameron@huawei.com --- drivers/iio/adc/ingenic-adc.c | 32 ++++++++++++++++++++++++++------ 1 file changed, 26 insertions(+), 6 deletions(-)
diff --git a/drivers/iio/adc/ingenic-adc.c b/drivers/iio/adc/ingenic-adc.c index 973e84deebea..1aafbe2cfe67 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 +191,41 @@ 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); + + 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; }