smb347-charger: Fix battery status reporting logic for charger faults

This patch checks for charger status register for determining the
battery charging status and reports Discharing/Charging/Not Charging/Full
accordingly.

This patch also adds the interrupt support for Safety Timer Expiration.
This interrupt is helpful in debugging the cause for charger fault.

Signed-off-by: Ramakrishna Pallala <ramakrishna.pallala@intel.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>

1 files changed, 82 insertions, 15 deletions

diff --git a/drivers/power/smb347-charger.c b/drivers/power/smb347-charger.c
index 332dd0110bd..a9707c11fbe 100644
--- a/drivers/power/smb347-charger.c
+++ b/drivers/power/smb347-charger.c
@@ -80,6 +80,7 @@
 #define CFG_FAULT_IRQ_DCIN_UV                   BIT(2)
 #define CFG_STATUS_IRQ                          0x0d
 #define CFG_STATUS_IRQ_TERMINATION_OR_TAPER     BIT(4)
+#define CFG_STATUS_IRQ_CHARGE_TIMEOUT           BIT(7)
 #define CFG_ADDRESS                             0x0e
 
 /* Command registers */
@@ -96,6 +97,9 @@
 #define IRQSTAT_C_TERMINATION_STAT              BIT(0)
 #define IRQSTAT_C_TERMINATION_IRQ               BIT(1)
 #define IRQSTAT_C_TAPER_IRQ                     BIT(3)
+#define IRQSTAT_D                               0x38
+#define IRQSTAT_D_CHARGE_TIMEOUT_STAT           BIT(2)
+#define IRQSTAT_D_CHARGE_TIMEOUT_IRQ            BIT(3)
 #define IRQSTAT_E                               0x39
 #define IRQSTAT_E_USBIN_UV_STAT                 BIT(0)
 #define IRQSTAT_E_USBIN_UV_IRQ                  BIT(1)
@@ -109,8 +113,10 @@
 #define STAT_B                                  0x3c
 #define STAT_C                                  0x3d
 #define STAT_C_CHG_ENABLED                      BIT(0)
+#define STAT_C_HOLDOFF_STAT                     BIT(3)
 #define STAT_C_CHG_MASK                         0x06
 #define STAT_C_CHG_SHIFT                        1
+#define STAT_C_CHG_TERM                         BIT(5)
 #define STAT_C_CHARGER_ERROR                    BIT(6)
 #define STAT_E                                  0x3f
 
@@ -701,7 +707,7 @@ fail:
 static irqreturn_t smb347_interrupt(int irq, void *data)
 {
         struct smb347_charger *smb = data;
-        unsigned int stat_c, irqstat_e, irqstat_c;
+        unsigned int stat_c, irqstat_c, irqstat_d, irqstat_e;
         bool handled = false;
         int ret;
 
@@ -717,6 +723,12 @@ static irqreturn_t smb347_interrupt(int irq, void *data)
                 return IRQ_NONE;
         }
 
+        ret = regmap_read(smb->regmap, IRQSTAT_D, &irqstat_d);
+        if (ret < 0) {
+                dev_warn(smb->dev, "reading IRQSTAT_D failed\n");
+                return IRQ_NONE;
+        }
+
         ret = regmap_read(smb->regmap, IRQSTAT_E, &irqstat_e);
         if (ret < 0) {
                 dev_warn(smb->dev, "reading IRQSTAT_E failed\n");
@@ -724,13 +736,11 @@ static irqreturn_t smb347_interrupt(int irq, void *data)
         }
 
         /*
-         * If we get charger error we report the error back to user and
-         * disable charging.
+         * If we get charger error we report the error back to user.
+         * If the error is recovered charging will resume again.
          */
         if (stat_c & STAT_C_CHARGER_ERROR) {
-                dev_err(smb->dev, "error in charger, disabling charging\n");
-
-                smb347_charging_disable(smb);
+                dev_err(smb->dev, "charging stopped due to charger error\n");
                 power_supply_changed(&smb->battery);
                 handled = true;
         }
@@ -743,6 +753,20 @@ static irqreturn_t smb347_interrupt(int irq, void *data)
         if (irqstat_c & (IRQSTAT_C_TERMINATION_IRQ | IRQSTAT_C_TAPER_IRQ)) {
                 if (irqstat_c & IRQSTAT_C_TERMINATION_STAT)
                         power_supply_changed(&smb->battery);
+                dev_dbg(smb->dev, "going to HW maintenance mode\n");
+                handled = true;
+        }
+
+        /*
+         * If we got a charger timeout INT that means the charge
+         * full is not detected with in charge timeout value.
+         */
+        if (irqstat_d & IRQSTAT_D_CHARGE_TIMEOUT_IRQ) {
+                dev_dbg(smb->dev, "total Charge Timeout INT received\n");
+
+                if (irqstat_d & IRQSTAT_D_CHARGE_TIMEOUT_STAT)
+                        dev_warn(smb->dev, "charging stopped due to timeout\n");
+                power_supply_changed(&smb->battery);
                 handled = true;
         }
 
@@ -776,6 +800,7 @@ static int smb347_irq_set(struct smb347_charger *smb, bool enable)
          * Enable/disable interrupts for:
          *      - under voltage
          *      - termination current reached
+         *      - charger timeout
          *      - charger error
          */
         ret = regmap_update_bits(smb->regmap, CFG_FAULT_IRQ, 0xff,
@@ -784,7 +809,8 @@ static int smb347_irq_set(struct smb347_charger *smb, bool enable)
                 goto fail;
 
         ret = regmap_update_bits(smb->regmap, CFG_STATUS_IRQ, 0xff,
-                        enable ? CFG_STATUS_IRQ_TERMINATION_OR_TAPER : 0);
+                        enable ? (CFG_STATUS_IRQ_TERMINATION_OR_TAPER |
+                                        CFG_STATUS_IRQ_CHARGE_TIMEOUT) : 0);
         if (ret < 0)
                 goto fail;
 
@@ -988,6 +1014,51 @@ static enum power_supply_property smb347_usb_properties[] = {
         POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE,
 };
 
+static int smb347_get_charging_status(struct smb347_charger *smb)
+{
+        int ret, status;
+        unsigned int val;
+
+        if (!smb347_is_ps_online(smb))
+                return POWER_SUPPLY_STATUS_DISCHARGING;
+
+        ret = regmap_read(smb->regmap, STAT_C, &val);
+        if (ret < 0)
+                return ret;
+
+        if ((val & STAT_C_CHARGER_ERROR) ||
+                        (val & STAT_C_HOLDOFF_STAT)) {
+                /*
+                 * set to NOT CHARGING upon charger error
+                 * or charging has stopped.
+                 */
+                status = POWER_SUPPLY_STATUS_NOT_CHARGING;
+        } else {
+                if ((val & STAT_C_CHG_MASK) >> STAT_C_CHG_SHIFT) {
+                        /*
+                         * set to charging if battery is in pre-charge,
+                         * fast charge or taper charging mode.
+                         */
+                        status = POWER_SUPPLY_STATUS_CHARGING;
+                } else if (val & STAT_C_CHG_TERM) {
+                        /*
+                         * set the status to FULL if battery is not in pre
+                         * charge, fast charge or taper charging mode AND
+                         * charging is terminated at least once.
+                         */
+                        status = POWER_SUPPLY_STATUS_FULL;
+                } else {
+                        /*
+                         * in this case no charger error or termination
+                         * occured but charging is not in progress!!!
+                         */
+                        status = POWER_SUPPLY_STATUS_NOT_CHARGING;
+                }
+        }
+
+        return status;
+}
+
 static int smb347_battery_get_property(struct power_supply *psy,
                                        enum power_supply_property prop,
                                        union power_supply_propval *val)
@@ -1003,14 +1074,10 @@ static int smb347_battery_get_property(struct power_supply *psy,
 
         switch (prop) {
         case POWER_SUPPLY_PROP_STATUS:
-                if (!smb347_is_ps_online(smb)) {
-                        val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
-                        break;
-                }
-                if (smb347_charging_status(smb))
-                        val->intval = POWER_SUPPLY_STATUS_CHARGING;
-                else
-                        val->intval = POWER_SUPPLY_STATUS_FULL;
+                ret = smb347_get_charging_status(smb);
+                if (ret < 0)
+                        return ret;
+                val->intval = ret;
                 break;
 
         case POWER_SUPPLY_PROP_CHARGE_TYPE: