linux-kernel - [PATCH AUTOSEL 4.9 46/99] mfd: mc13xxx-core: Fix PMIC shutdown when reading ADC values

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Date:   Sat, 16 Nov 2019 10:50:09 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Fabio Estevam <fabio.estevam@....com>,
        Chris Healy <cphealy@...il.com>,
        Lee Jones <lee.jones@...aro.org>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH AUTOSEL 4.9 46/99] mfd: mc13xxx-core: Fix PMIC shutdown when reading ADC values

From: Fabio Estevam <fabio.estevam@....com>

[ Upstream commit 55143439b7b501882bea9d95a54adfe00ffc79a3 ]

When trying to read any MC13892 ADC channel on a imx51-babbage board:

The MC13892 PMIC shutdowns completely.

After debugging this issue and comparing the MC13892 and MC13783
initializations done in the vendor kernel, it was noticed that the
CHRGRAWDIV bit of the ADC0 register was not being set.

This bit is set by default after power on, but the driver was
clearing it.

After setting this bit it is possible to read the ADC values correctly.

Signed-off-by: Fabio Estevam <fabio.estevam@....com>
Tested-by: Chris Healy <cphealy@...il.com>
Signed-off-by: Lee Jones <lee.jones@...aro.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/mfd/mc13xxx-core.c  | 3 ++-
 include/linux/mfd/mc13xxx.h | 1 +
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/mfd/mc13xxx-core.c b/drivers/mfd/mc13xxx-core.c
index 6c16f170529f5..75d52034f89da 100644
--- a/drivers/mfd/mc13xxx-core.c
+++ b/drivers/mfd/mc13xxx-core.c
@@ -278,7 +278,8 @@ int mc13xxx_adc_do_conversion(struct mc13xxx *mc13xxx, unsigned int mode,
 	if (ret)
 		goto out;
 
-	adc0 = MC13XXX_ADC0_ADINC1 | MC13XXX_ADC0_ADINC2;
+	adc0 = MC13XXX_ADC0_ADINC1 | MC13XXX_ADC0_ADINC2 |
+	       MC13XXX_ADC0_CHRGRAWDIV;
 	adc1 = MC13XXX_ADC1_ADEN | MC13XXX_ADC1_ADTRIGIGN | MC13XXX_ADC1_ASC;
 
 	if (channel > 7)
diff --git a/include/linux/mfd/mc13xxx.h b/include/linux/mfd/mc13xxx.h
index 638222e43e489..93011c61aafd2 100644
--- a/include/linux/mfd/mc13xxx.h
+++ b/include/linux/mfd/mc13xxx.h
@@ -247,6 +247,7 @@ struct mc13xxx_platform_data {
 #define MC13XXX_ADC0_TSMOD0		(1 << 12)
 #define MC13XXX_ADC0_TSMOD1		(1 << 13)
 #define MC13XXX_ADC0_TSMOD2		(1 << 14)
+#define MC13XXX_ADC0_CHRGRAWDIV		(1 << 15)
 #define MC13XXX_ADC0_ADINC1		(1 << 16)
 #define MC13XXX_ADC0_ADINC2		(1 << 17)
 
-- 
2.20.1