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Subject[PATCH AUTOSEL for-4.9 29/53] power: supply: axp288_fuel_gauge: Read 12 bit values 2 registers at a time
Date
From: Hans de Goede <hdegoede@redhat.com>

[ Upstream commit 248efcf00602f0282587999bcc221a872bd72530 ]

In order for the MSB -> LSB latching to work correctly we must read the
2 8 bit registers of a 12 bit value in one consecutive read.

This fixes voltage_ocv reporting inconsistent values on my tablet.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
---
drivers/power/supply/axp288_fuel_gauge.c | 40 ++++++++++++++++++--------------
1 file changed, 22 insertions(+), 18 deletions(-)

diff --git a/drivers/power/supply/axp288_fuel_gauge.c b/drivers/power/supply/axp288_fuel_gauge.c
index 99d6d3030731..089056cb8e73 100644
--- a/drivers/power/supply/axp288_fuel_gauge.c
+++ b/drivers/power/supply/axp288_fuel_gauge.c
@@ -210,6 +210,22 @@ static int fuel_gauge_read_15bit_word(struct axp288_fg_info *info, int reg)
return ret & FG_15BIT_VAL_MASK;
}

+static int fuel_gauge_read_12bit_word(struct axp288_fg_info *info, int reg)
+{
+ unsigned char buf[2];
+ int ret;
+
+ ret = regmap_bulk_read(info->regmap, reg, buf, 2);
+ if (ret < 0) {
+ dev_err(&info->pdev->dev, "Error reading reg 0x%02x err: %d\n",
+ reg, ret);
+ return ret;
+ }
+
+ /* 12-bit data values have upper 8 bits in buf[0], lower 4 in buf[1] */
+ return (buf[0] << 4) | ((buf[1] >> 4) & 0x0f);
+}
+
static int pmic_read_adc_val(const char *name, int *raw_val,
struct axp288_fg_info *info)
{
@@ -270,12 +286,9 @@ static int fuel_gauge_debug_show(struct seq_file *s, void *data)
seq_printf(s, " FG_RDC0[%02x] : %02x\n",
AXP288_FG_RDC0_REG,
fuel_gauge_reg_readb(info, AXP288_FG_RDC0_REG));
- seq_printf(s, " FG_OCVH[%02x] : %02x\n",
+ seq_printf(s, " FG_OCV[%02x] : %04x\n",
AXP288_FG_OCVH_REG,
- fuel_gauge_reg_readb(info, AXP288_FG_OCVH_REG));
- seq_printf(s, " FG_OCVL[%02x] : %02x\n",
- AXP288_FG_OCVL_REG,
- fuel_gauge_reg_readb(info, AXP288_FG_OCVL_REG));
+ fuel_gauge_read_12bit_word(info, AXP288_FG_OCVH_REG));
seq_printf(s, " FG_DES_CAP[%02x] : %04x\n",
AXP288_FG_DES_CAP1_REG,
fuel_gauge_read_15bit_word(info, AXP288_FG_DES_CAP1_REG));
@@ -532,21 +545,12 @@ temp_read_fail:

static int fuel_gauge_get_vocv(struct axp288_fg_info *info, int *vocv)
{
- int ret, value;
-
- /* 12-bit data value, upper 8 in OCVH, lower 4 in OCVL */
- ret = fuel_gauge_reg_readb(info, AXP288_FG_OCVH_REG);
- if (ret < 0)
- goto vocv_read_fail;
- value = ret << 4;
+ int ret;

- ret = fuel_gauge_reg_readb(info, AXP288_FG_OCVL_REG);
- if (ret < 0)
- goto vocv_read_fail;
- value |= (ret & 0xf);
+ ret = fuel_gauge_read_12bit_word(info, AXP288_FG_OCVH_REG);
+ if (ret >= 0)
+ *vocv = VOLTAGE_FROM_ADC(ret);

- *vocv = VOLTAGE_FROM_ADC(value);
-vocv_read_fail:
return ret;
}

--
2.11.0
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