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

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>

diff --git a/drivers/hwmon/ina3221.c b/drivers/hwmon/ina3221.c
index 74d39d2..62040aa 100644 (file)
--- a/drivers/hwmon/ina3221.c
+++ b/drivers/hwmon/ina3221.c
@@ -309,21 +309,22 @@ static int ina3221_write_chip(struct device *dev, u32 attr, long val)
 {
        struct ina3221_data *ina = dev_get_drvdata(dev);
        int ret, idx;
+       u32 tmp;
 
        switch (attr) {
        case hwmon_chip_samples:
                idx = find_closest(val, ina3221_avg_samples,
                                   ARRAY_SIZE(ina3221_avg_samples));
 
-               ret = regmap_update_bits(ina->regmap, INA3221_CONFIG,
-                                        INA3221_CONFIG_AVG_MASK,
-                                        idx << INA3221_CONFIG_AVG_SHIFT);
+               tmp = (ina->reg_config & ~INA3221_CONFIG_AVG_MASK) |
+                     (idx << INA3221_CONFIG_AVG_SHIFT);
+               ret = regmap_write(ina->regmap, INA3221_CONFIG, tmp);
                if (ret)
                        return ret;
 
                /* Update reg_config accordingly */
-               return regmap_read(ina->regmap, INA3221_CONFIG,
-                                  &ina->reg_config);
+               ina->reg_config = tmp;
+               return 0;
        default:
                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);
        u16 config, mask = INA3221_CONFIG_CHx_EN(channel);
        u16 config_old = ina->reg_config & mask;
+       u32 tmp;
        int ret;
 
        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 */
-       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)
                goto fail;
 
        /* Cache the latest config register value */
-       ret = regmap_read(ina->regmap, INA3221_CONFIG, &ina->reg_config);
-       if (ret)
-               goto fail;
+       ina->reg_config = tmp;
 
        /* For disabling routine, decrease refcount or suspend() at last */
        if (!enable)