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power: supply: axp288_fuel_gauge: Drop retry logic from fuel_gauge_reg_readb()

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The I2C-bus to the XPower AXP288 is shared between the Linux kernel and
the SoCs P-Unit. The P-Unit has a semaphore which the kernel must "lock"
before it may use the bus. This semaphore is automatically taken by the
I2C-bus-driver.

The retry on -EBUSY logic in fuel_gauge_reg_readb() likely was added to
deal with the I2C-bus-drive returning -EBUSY when it failed to take the
semaphore, but this really should never happen. The semaphore code even
has a WARN_ON(ret) to log a kernel backtrace if this does somehow happen,
when this happens something is seriously wrong and the system typically
freezes soon afterwards.

TL;DR: the regmap_read() should never fail with -EBUSY so the retries
are unnecessary.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
This commit is contained in:
Hans de Goede 2021-08-01 15:31:00 +02:00 committed by Sebastian Reichel
parent caa534c3ba
commit f17bda7f65
1 changed files with 2 additions and 8 deletions
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10
drivers/power/supply/axp288_fuel_gauge.c
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@ -76,7 +76,6 @@
#define FG_LOW_CAP_CRIT_THR 4 /* 4 perc */
#define FG_LOW_CAP_SHDN_THR 0 /* 0 perc */
#define NR_RETRY_CNT 3
#define DEV_NAME "axp288_fuel_gauge"
/* 1.1mV per LSB expressed in uV */
@ -132,15 +131,10 @@ static enum power_supply_property fuel_gauge_props[] = {
static int fuel_gauge_reg_readb(struct axp288_fg_info *info, int reg)
{
int ret, i;
unsigned int val;
int ret;
for (i = 0; i < NR_RETRY_CNT; i++) {
ret = regmap_read(info->regmap, reg, &val);
if (ret != -EBUSY)
break;
}
ret = regmap_read(info->regmap, reg, &val);
if (ret < 0) {
dev_err(&info->pdev->dev, "Error reading reg 0x%02x err: %d\n", reg, ret);
return ret;