hwmon: (gl518sm) Report error on invalid fan div value

If the user attempts to write a fan clock divider not supported by
the chip, an error should be returned.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Mark M. Hoffman <mhoffman@lightlink.com>

1 files changed, 12 insertions, 2 deletions

diff --git a/drivers/hwmon/gl518sm.c b/drivers/hwmon/gl518sm.c
index 535ad8776a68..c5255118bc16 100644
--- a/drivers/hwmon/gl518sm.c
+++ b/drivers/hwmon/gl518sm.c
@@ -107,7 +107,6 @@ static inline u8 FAN_TO_REG(long rpm, int div)
 #define VDD_TO_REG(val)         (SENSORS_LIMIT((((val)*4+47)/95),0,255))
 #define VDD_FROM_REG(val)       (((val)*95+2)/4)
 
-#define DIV_TO_REG(val)         ((val)==4?2:(val)==2?1:(val)==1?0:3)
 #define DIV_FROM_REG(val)       (1 << (val))
 
 #define BEEP_MASK_TO_REG(val)   ((val) & 0x7f & data->alarm_mask)
@@ -302,9 +301,20 @@ static ssize_t set_fan_div(struct device *dev, struct device_attribute *attr,
         int regvalue;
         unsigned long val = simple_strtoul(buf, NULL, 10);
 
+        switch (val) {
+        case 1: val = 0; break;
+        case 2: val = 1; break;
+        case 4: val = 2; break;
+        case 8: val = 3; break;
+        default:
+                dev_err(dev, "Invalid fan clock divider %lu, choose one "
+                        "of 1, 2, 4 or 8\n", val);
+                return -EINVAL;
+        }
+
         mutex_lock(&data->update_lock);
         regvalue = gl518_read_value(client, GL518_REG_MISC);
-        data->fan_div[nr] = DIV_TO_REG(val);
+        data->fan_div[nr] = val;
         regvalue = (regvalue & ~(0xc0 >> (2 * nr)))
                  | (data->fan_div[nr] << (6 - 2 * nr));
         gl518_write_value(client, GL518_REG_MISC, regvalue);