regulator: qpnp-labibb: Handle LAB short circuit(SC) detection

On certain PMICs, there is no short circuit (SC) detection available
in LAB module. Add support to detect it manually and disable LAB/IBB
module upon SC detection. In addition, notify it to OLEDB driver to
disable OLEDB module.

Change-Id: I2a9dc5b1ae8ece45c85b3992026c7f389fd4d135
Signed-off-by: Kiran Gunda <kgunda@codeaurora.org>

Documentation/devicetree/bindings/regulator/qpnp-labibb-regulator.txt

@@ -151,6 +151,10 @@ LAB subnode optional properties:
 					any value in the allowed limit.
 - qcom,notify-lab-vreg-ok-sts:		A boolean property which upon set will
 					poll and notify the lab_vreg_ok status.
+- qcom,qpnp-lab-sc-wait-time-ms:	This property is used to specify the time
+					(in ms) to poll for the short circuit
+					detection. If not specified the default time
+					is 5 sec.
 
 Following properties are available only for PM660A:
 

drivers/regulator/qpnp-labibb-regulator.c

@@ -559,6 +559,7 @@ struct lab_regulator {
 	int				step_size;
 	int				slew_rate;
 	int				soft_start;
+	int				sc_wait_time_ms;
 
 	int				vreg_enabled;
 };
@@ -608,6 +609,8 @@ struct qpnp_labibb {
 	bool				skip_2nd_swire_cmd;
 	bool				pfm_enable;
 	bool				notify_lab_vreg_ok_sts;
+	bool				detect_lab_sc;
+	bool				sc_detected;
 	u32				swire_2nd_cmd_delay;
 	u32				swire_ibb_ps_enable_delay;
 };
@@ -2138,8 +2141,10 @@ static void qpnp_lab_vreg_notifier_work(struct work_struct *work)
 	u8 val;
 	struct qpnp_labibb *labibb  = container_of(work, struct qpnp_labibb,
 							lab_vreg_ok_work);
+	if (labibb->lab_vreg.sc_wait_time_ms != -EINVAL)
+		retries = labibb->lab_vreg.sc_wait_time_ms / 5;
 
-	while (retries--) {
+	while (retries) {
 		rc = qpnp_labibb_read(labibb, labibb->lab_base +
 					REG_LAB_STATUS1, &val, 1);
 		if (rc < 0) {
@@ -2155,10 +2160,30 @@ static void qpnp_lab_vreg_notifier_work(struct work_struct *work)
 		}
 
 		usleep_range(dly, dly + 100);
+		retries--;
 	}
 
-	if (!retries)
+	if (!retries) {
-		pr_err("LAB_VREG_OK not set, failed to notify\n");
+		if (labibb->detect_lab_sc) {
+			pr_crit("short circuit detected on LAB rail.. disabling the LAB/IBB/OLEDB modules\n");
+			/* Disable LAB module */
+			val = 0;
+			rc = qpnp_labibb_write(labibb, labibb->lab_base +
+					REG_LAB_MODULE_RDY, &val, 1);
+			if (rc < 0) {
+				pr_err("write register %x failed rc = %d\n",
+					REG_LAB_MODULE_RDY, rc);
+				return;
+			}
+			raw_notifier_call_chain(&labibb_notifier,
+						LAB_VREG_NOT_OK, NULL);
+			labibb->sc_detected = true;
+			labibb->lab_vreg.vreg_enabled = 0;
+			labibb->ibb_vreg.vreg_enabled = 0;
+		} else {
+			pr_err("LAB_VREG_OK not set, failed to notify\n");
+		}
+	}
 }
 
 static int qpnp_labibb_regulator_enable(struct qpnp_labibb *labibb)
@@ -2323,6 +2348,11 @@ static int qpnp_lab_regulator_enable(struct regulator_dev *rdev)
 
 	struct qpnp_labibb *labibb  = rdev_get_drvdata(rdev);
 
+	if (labibb->sc_detected) {
+		pr_info("Short circuit detected: disabled LAB/IBB rails\n");
+		return 0;
+	}
+
 	if (labibb->skip_2nd_swire_cmd) {
 		rc = qpnp_ibb_ps_config(labibb, false);
 		if (rc < 0) {
@@ -2363,7 +2393,7 @@ static int qpnp_lab_regulator_enable(struct regulator_dev *rdev)
 		labibb->lab_vreg.vreg_enabled = 1;
 	}
 
-	if (labibb->notify_lab_vreg_ok_sts)
+	if (labibb->notify_lab_vreg_ok_sts || labibb->detect_lab_sc)
 		schedule_work(&labibb->lab_vreg_ok_work);
 
 	return 0;
@@ -2621,6 +2651,12 @@ static int register_qpnp_lab_regulator(struct qpnp_labibb *labibb,
 	labibb->notify_lab_vreg_ok_sts = of_property_read_bool(of_node,
 					"qcom,notify-lab-vreg-ok-sts");
 
+	labibb->lab_vreg.sc_wait_time_ms = -EINVAL;
+	if (labibb->pmic_rev_id->pmic_subtype == PM660L_SUBTYPE &&
+					labibb->detect_lab_sc)
+		of_property_read_u32(of_node, "qcom,qpnp-lab-sc-wait-time-ms",
+					&labibb->lab_vreg.sc_wait_time_ms);
+
 	rc = of_property_read_u32(of_node, "qcom,qpnp-lab-soft-start",
 					&(labibb->lab_vreg.soft_start));
 	if (!rc) {
@@ -3255,6 +3291,11 @@ static int qpnp_ibb_regulator_enable(struct regulator_dev *rdev)
 	u8 val;
 	struct qpnp_labibb *labibb  = rdev_get_drvdata(rdev);
 
+	if (labibb->sc_detected) {
+		pr_info("Short circuit detected: disabled LAB/IBB rails\n");
+		return 0;
+	}
+
 	if (!labibb->ibb_vreg.vreg_enabled && !labibb->swire_control) {
 
 		if (!labibb->standalone)
@@ -3731,6 +3772,8 @@ static int qpnp_labibb_regulator_probe(struct platform_device *pdev)
 
 	if (labibb->pmic_rev_id->pmic_subtype == PM660L_SUBTYPE) {
 		labibb->mode = QPNP_LABIBB_AMOLED_MODE;
+		/* Enable polling for LAB short circuit detection for PM660A */
+		labibb->detect_lab_sc = true;
 	} else {
 		rc = of_property_read_string(labibb->dev->of_node,
 				"qcom,qpnp-labibb-mode", &mode_name);

include/linux/regulator/qpnp-labibb-regulator.h

@@ -15,6 +15,7 @@
 
 enum labibb_notify_event {
 	LAB_VREG_OK = 1,
+	LAB_VREG_NOT_OK,
 };
 
 int qpnp_labibb_notifier_register(struct notifier_block *nb);