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hwmon: (ina3221) Do not read-back to cache reg_config

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Reading back the CONFIG register increases an extra I2C
transaction. This's not necessary and could be replaced
with a local variable caching the register settings.

So this patch replaces two readback regmap_read() calls
with a tmp variable.

Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
This commit is contained in:
Nicolin Chen
2019-04-17 16:12:09 -07:00
committed by Guenter Roeck
parent 7ebd8b66dd
commit 521c0b6116
1 changed files with 10 additions and 9 deletions
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19
drivers/hwmon/ina3221.c
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@@ -309,21 +309,22 @@ static int ina3221_write_chip(struct device *dev, u32 attr, long val)
{ {
struct ina3221_data *ina = dev_get_drvdata(dev); struct ina3221_data *ina = dev_get_drvdata(dev);
int ret, idx; int ret, idx;
u32 tmp;
switch (attr) { switch (attr) {
case hwmon_chip_samples: case hwmon_chip_samples:
idx = find_closest(val, ina3221_avg_samples, idx = find_closest(val, ina3221_avg_samples,
ARRAY_SIZE(ina3221_avg_samples)); ARRAY_SIZE(ina3221_avg_samples));
ret = regmap_update_bits(ina->regmap, INA3221_CONFIG, tmp = (ina->reg_config & ~INA3221_CONFIG_AVG_MASK) |
INA3221_CONFIG_AVG_MASK, (idx << INA3221_CONFIG_AVG_SHIFT);
idx << INA3221_CONFIG_AVG_SHIFT); ret = regmap_write(ina->regmap, INA3221_CONFIG, tmp);
if (ret) if (ret)
return ret; return ret;
/* Update reg_config accordingly */ /* Update reg_config accordingly */
return regmap_read(ina->regmap, INA3221_CONFIG, ina->reg_config = tmp;
&ina->reg_config); return 0;
default: default:
return -EOPNOTSUPP; return -EOPNOTSUPP;
} }
@@ -359,6 +360,7 @@ static int ina3221_write_enable(struct device *dev, int channel, bool enable)
struct ina3221_data *ina = dev_get_drvdata(dev); struct ina3221_data *ina = dev_get_drvdata(dev);
u16 config, mask = INA3221_CONFIG_CHx_EN(channel); u16 config, mask = INA3221_CONFIG_CHx_EN(channel);
u16 config_old = ina->reg_config & mask; u16 config_old = ina->reg_config & mask;
u32 tmp;
int ret; int ret;
config = enable ? mask : 0; config = enable ? mask : 0;
@@ -377,14 +379,13 @@ static int ina3221_write_enable(struct device *dev, int channel, bool enable)
} }
/* Enable or disable the channel */ /* Enable or disable the channel */
ret = regmap_update_bits(ina->regmap, INA3221_CONFIG, mask, config); tmp = (ina->reg_config & ~mask) | (config & mask);
ret = regmap_write(ina->regmap, INA3221_CONFIG, tmp);
if (ret) if (ret)
goto fail; goto fail;
/* Cache the latest config register value */ /* Cache the latest config register value */
ret = regmap_read(ina->regmap, INA3221_CONFIG, &ina->reg_config); ina->reg_config = tmp;
if (ret)
goto fail;
/* For disabling routine, decrease refcount or suspend() at last */ /* For disabling routine, decrease refcount or suspend() at last */
if (!enable) if (!enable)