hwmon: (w83795) Avoid reading the same register twice

Shorten driver load time by avoiding duplicate register access during
initialization. This saves 112 ms on modprobe on my test system.

Signed-off-by: Jean Delvare <khali@linux-fr.org>

1 files changed, 9 insertions, 2 deletions

diff --git a/drivers/hwmon/w83795.c b/drivers/hwmon/w83795.c
index fd70a7b46295..aea3275f5dae 100644
--- a/drivers/hwmon/w83795.c
+++ b/drivers/hwmon/w83795.c
@@ -1986,6 +1986,9 @@ static int w83795_probe(struct i2c_client *client,
                 data->in[i][IN_READ] = tmp;
         }
         for (i = 0; i < IN_LSB_REG_NUM; i++) {
+                if ((i == 2 && data->chip_type == w83795adg) ||
+                    (i >= 4 && !(data->has_in & (1 << (i + 11)))))
+                        continue;
                 data->in_lsb[i][IN_MAX] =
                         w83795_read(client, IN_LSB_REG(i, IN_MAX));
                 data->in_lsb[i][IN_LOW] =
@@ -1995,13 +1998,17 @@ static int w83795_probe(struct i2c_client *client,
 
         /* First update fan and limits */
         for (i = 0; i < ARRAY_SIZE(data->fan); i++) {
+                /* Each register contains LSB for 2 fans, but we want to
+                 * read it only once to save time */
+                if ((i & 1) == 0 && (data->has_fan & (3 << i)))
+                        tmp = w83795_read(client, W83795_REG_FAN_MIN_LSB(i));
+
                 if (!(data->has_fan & (1 << i)))
                         continue;
                 data->fan_min[i] =
                         w83795_read(client, W83795_REG_FAN_MIN_HL(i)) << 4;
                 data->fan_min[i] |=
-                  (w83795_read(client, W83795_REG_FAN_MIN_LSB(i)) >>
-                        W83795_REG_FAN_MIN_LSB_SHIFT(i)) & 0x0F;
+                        (tmp >> W83795_REG_FAN_MIN_LSB_SHIFT(i)) & 0x0F;
                 data->fan[i] = w83795_read(client, W83795_REG_FAN(i)) << 4;
                 data->fan[i] |=
                   (w83795_read(client, W83795_REG_VRLSB) >> 4) & 0x0F;