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authorJean Delvare <khali@linux-fr.org>2010-10-28 20:31:47 +0200
committerJean Delvare <khali@endymion.delvare>2010-10-28 20:31:47 +0200
commitc1a792a6eea42d88a99e6ace215b22fbdb76c7b6 (patch)
tree92c6f630e7044fdd65100326ed0489a6cc1f5b0a /drivers/hwmon/w83795.c
parent02728ffef9c2cf067e654e832b8c282a8a4d0b16 (diff)
downloadlinux-c1a792a6eea42d88a99e6ace215b22fbdb76c7b6.tar.gz
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>
Diffstat (limited to 'drivers/hwmon/w83795.c')
-rw-r--r--drivers/hwmon/w83795.c11
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;