hwmon: (sch5627) Trigger Vbat measurements

The sch5627 needs to be explicitly told to start an adc conversion
for Vbat, once in a while. Without this Vbat may read 0, and will never
get updated.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

1 files changed, 22 insertions, 1 deletions

diff --git a/drivers/hwmon/sch5627.c b/drivers/hwmon/sch5627.c
index d785a2c5431f..020c87273ea1 100644
--- a/drivers/hwmon/sch5627.c
+++ b/drivers/hwmon/sch5627.c
@@ -97,11 +97,13 @@ static const char * const SCH5627_IN_LABELS[SCH5627_NO_IN] = {
 struct sch5627_data {
         unsigned short addr;
         struct device *hwmon_dev;
+        u8 control;
         u8 temp_max[SCH5627_NO_TEMPS];
         u8 temp_crit[SCH5627_NO_TEMPS];
         u16 fan_min[SCH5627_NO_FANS];
 
         struct mutex update_lock;
+        unsigned long last_battery;     /* In jiffies */
         char valid;                     /* !=0 if following fields are valid */
         unsigned long last_updated;     /* In jiffies */
         u16 temp[SCH5627_NO_TEMPS];
@@ -243,6 +245,12 @@ static int sch5627_read_virtual_reg(struct sch5627_data *data, u16 reg)
         return sch5627_send_cmd(data, SCH5627_CMD_READ, reg, 0);
 }
 
+static int sch5627_write_virtual_reg(struct sch5627_data *data,
+                                     u16 reg, u8 val)
+{
+        return sch5627_send_cmd(data, SCH5627_CMD_WRITE, reg, val);
+}
+
 static int sch5627_read_virtual_reg16(struct sch5627_data *data, u16 reg)
 {
         int lsb, msb;
@@ -287,6 +295,13 @@ static struct sch5627_data *sch5627_update_device(struct device *dev)
 
         mutex_lock(&data->update_lock);
 
+        /* Trigger a Vbat voltage measurement every 5 minutes */
+        if (time_after(jiffies, data->last_battery + 300 * HZ)) {
+                sch5627_write_virtual_reg(data, SCH5627_REG_CTRL,
+                                          data->control | 0x10);
+                data->last_battery = jiffies;
+        }
+
         /* Cache the values for 1 second */
         if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
                 for (i = 0; i < SCH5627_NO_TEMPS; i++) {
@@ -711,11 +726,17 @@ static int __devinit sch5627_probe(struct platform_device *pdev)
                 err = val;
                 goto error;
         }
-        if (!(val & 0x01)) {
+        data->control = val;
+        if (!(data->control & 0x01)) {
                 pr_err("hardware monitoring not enabled\n");
                 err = -ENODEV;
                 goto error;
         }
+        /* Trigger a Vbat voltage measurement, so that we get a valid reading
+           the first time we read Vbat */
+        sch5627_write_virtual_reg(data, SCH5627_REG_CTRL,
+                                  data->control | 0x10);
+        data->last_battery = jiffies;
 
         /*
          * Read limits, we do this only once as reading a register on