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>

1 files changed, 10 insertions, 9 deletions

diff --git a/drivers/hwmon/ina3221.c b/drivers/hwmon/ina3221.c
index 74d39d212931..62040aac653c 100644
--- 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)