hwmon: (w83l768ng) Fix fan speed control range

The W83L786NG stores the fan speed on 4 bits while the sysfs interface
uses a 0-255 range. Thus the driver should scale the user input down
to map it to the device range, and scale up the value read from the
device before presenting it to the user. The reserved register nibble
should be left unchanged.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: stable@vger.kernel.org
Reviewed-by: Guenter Roeck <linux@roeck-us.net>

diff --git a/drivers/hwmon/w83l786ng.c b/drivers/hwmon/w83l786ng.c
index f190219fa84dd23fd4245951fd55471c3dc1efd6..6ed76ceb92709078497571ad4cb6f8740d3490bb 100644 (file)
--- a/drivers/hwmon/w83l786ng.c
+++ b/drivers/hwmon/w83l786ng.c
@@ -481,9 +481,11 @@ store_pwm(struct device *dev, struct device_attribute *attr,
        if (err)
                return err;
        val = clamp_val(val, 0, 255);
+       val = DIV_ROUND_CLOSEST(val, 0x11);
 
        mutex_lock(&data->update_lock);
-       data->pwm[nr] = val;
+       data->pwm[nr] = val * 0x11;
+       val |= w83l786ng_read_value(client, W83L786NG_REG_PWM[nr]) & 0xf0;
        w83l786ng_write_value(client, W83L786NG_REG_PWM[nr], val);
        mutex_unlock(&data->update_lock);
        return count;
@@ -777,8 +779,9 @@ static struct w83l786ng_data *w83l786ng_update_device(struct device *dev)
                            ? 0 : 1;
                        data->pwm_enable[i] =
                            ((pwmcfg >> W83L786NG_PWM_ENABLE_SHIFT[i]) & 3) + 1;
-                       data->pwm[i] = w83l786ng_read_value(client,
-                           W83L786NG_REG_PWM[i]);
+                       data->pwm[i] =
+                           (w83l786ng_read_value(client, W83L786NG_REG_PWM[i])
+                            & 0x0f) * 0x11;
                }