hwmon: (lm85) Don't write back cached values

In set_pwm_auto_pwm_minctl, we write cached register bits back to the
chip. This is a bad idea as we have no guarantee that the cache is
up-to-date. Better read a fresh register value from the chip, it's
safer and in fact it is also more simple.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Juerg Haefliger <juergh at gmail.com>
Signed-off-by: Mark M. Hoffman <mhoffman@lightlink.com>

1 files changed, 6 insertions, 9 deletions

diff --git a/drivers/hwmon/lm85.c b/drivers/hwmon/lm85.c
index 0d31435b333c..645b98c187c2 100644
--- a/drivers/hwmon/lm85.c
+++ b/drivers/hwmon/lm85.c
@@ -308,10 +308,8 @@ struct lm85_data {
         u8 pwm[3];              /* Register value */
         u8 temp_ext[3];         /* Decoded values */
         u8 in_ext[8];           /* Decoded values */
-        u8 smooth[1];           /* Register encoding */
         u8 vid;                 /* Register value */
         u8 vrm;                 /* VRM version */
-        u8 syncpwm3;            /* Saved PWM3 for TACH 2,3,4 config */
         u32 alarms;             /* Register encoding, combined */
         struct lm85_autofan autofan[3];
         struct lm85_zone zone[3];
@@ -756,14 +754,15 @@ static ssize_t set_pwm_auto_pwm_minctl(struct device *dev,
         struct i2c_client *client = to_i2c_client(dev);
         struct lm85_data *data = i2c_get_clientdata(client);
         long val = simple_strtol(buf, NULL, 10);
+        u8 tmp;
 
         mutex_lock(&data->update_lock);
         data->autofan[nr].min_off = val;
-        lm85_write_value(client, LM85_REG_AFAN_SPIKE1, data->smooth[0]
-                | data->syncpwm3
-                | (data->autofan[0].min_off ? 0x20 : 0)
-                | (data->autofan[1].min_off ? 0x40 : 0)
-                | (data->autofan[2].min_off ? 0x80 : 0));
+        tmp = lm85_read_value(client, LM85_REG_AFAN_SPIKE1);
+        tmp &= ~(0x20 << nr);
+        if (data->autofan[nr].min_off)
+                tmp |= 0x20 << nr;
+        lm85_write_value(client, LM85_REG_AFAN_SPIKE1, tmp);
         mutex_unlock(&data->update_lock);
         return count;
 }
@@ -1531,8 +1530,6 @@ static struct lm85_data *lm85_update_device(struct device *dev)
                 }
 
                 i = lm85_read_value(client, LM85_REG_AFAN_SPIKE1);
-                data->smooth[0] = i & 0x0f;
-                data->syncpwm3 = i & 0x10;  /* Save PWM3 config */
                 data->autofan[0].min_off = (i & 0x20) != 0;
                 data->autofan[1].min_off = (i & 0x40) != 0;
                 data->autofan[2].min_off = (i & 0x80) != 0;