regulator: cpr3: Use default step_quot during corner switch

Configure CPR4/h controllers to reset to default step_quot on each
loop_en = 0 transition. This enables the CPR controller to use the
default step_quot during a corner switch and then later switch to
the run-time calibrated step_quot. Without this feature enabled,
there is a chance for the CPR controller to use the run-time
calibrated step_quot of lower modes for higher modes that sometimes
can lead to closed-loop voltage getting stuck at open-loop voltage.

CRs-Fixed: 2003482
Change-Id: Ic738f6205a2e2030202abd811e94bd47240bad43
Signed-off-by: Tirupathi Reddy <tirupath@codeaurora.org>

4 files changed, 35 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/regulator/cpr3-regulator.txt b/Documentation/devicetree/bindings/regulator/cpr3-regulator.txt
index af53e59cd87f..37e8391259c6 100644
--- a/Documentation/devicetree/bindings/regulator/cpr3-regulator.txt
+++ b/Documentation/devicetree/bindings/regulator/cpr3-regulator.txt
@@ -209,6 +209,15 @@ Platform independent properties:
 		    as the corresponding addresses are specified in
 		    the qcom,cpr-panic-reg-addr-list property.
 
+- qcom,cpr-reset-step-quot-loop-en
+	Usage:      optional; only meaningful for CPR4 and CPRh controllers
+	Value type: <empty>
+	Definition: Boolean value which indicates that the CPR controller should
+		    be configured to reset step_quot on each loop_en = 0
+		    transition. This configuration allows the CPR controller to
+		    first use the default step_quot and then later switch to the
+		    run-time calibrated step_quot.
+
 =================================================
 Second Level Nodes - CPR Threads for a Controller
 =================================================
diff --git a/drivers/regulator/cpr3-regulator.c b/drivers/regulator/cpr3-regulator.c
index c51ed182ba96..3ffe094fe53c 100644
--- a/drivers/regulator/cpr3-regulator.c
+++ b/drivers/regulator/cpr3-regulator.c
@@ -174,6 +174,7 @@
 #define CPR4_CPR_TIMER_CLAMP_THREAD_AGGREGATION_EN	BIT(27)
 
 #define CPR4_REG_MISC				0x700
+#define CPR4_MISC_RESET_STEP_QUOT_LOOP_EN	BIT(2)
 #define CPR4_MISC_MARGIN_TABLE_ROW_SELECT_MASK	GENMASK(23, 20)
 #define CPR4_MISC_MARGIN_TABLE_ROW_SELECT_SHIFT	20
 #define CPR4_MISC_TEMP_SENSOR_ID_START_MASK	GENMASK(27, 24)
@@ -698,6 +699,11 @@ static int cpr3_regulator_init_cpr4(struct cpr3_controller *ctrl)
 	int thread_id = 0;
 	u64 temp;
 
+	if (ctrl->reset_step_quot_loop_en)
+		cpr3_masked_write(ctrl, CPR4_REG_MISC,
+				CPR4_MISC_RESET_STEP_QUOT_LOOP_EN,
+				CPR4_MISC_RESET_STEP_QUOT_LOOP_EN);
+
 	if (ctrl->supports_hw_closed_loop) {
 		if (ctrl->saw_use_unit_mV)
 			pmic_step_size = ctrl->step_volt / 1000;
@@ -1310,6 +1316,11 @@ static int cpr3_regulator_init_cprh(struct cpr3_controller *ctrl)
 		return rc;
 	}
 
+	if (ctrl->reset_step_quot_loop_en)
+		cpr3_masked_write(ctrl, CPR4_REG_MISC,
+				CPR4_MISC_RESET_STEP_QUOT_LOOP_EN,
+				CPR4_MISC_RESET_STEP_QUOT_LOOP_EN);
+
 	if (ctrl->saw_use_unit_mV)
 		pmic_step_size = ctrl->step_volt / 1000;
 	cpr3_masked_write(ctrl, CPR4_REG_MARGIN_ADJ_CTL,
diff --git a/drivers/regulator/cpr3-regulator.h b/drivers/regulator/cpr3-regulator.h
index 7dae23ca0e70..1ac0f7b816b3 100644
--- a/drivers/regulator/cpr3-regulator.h
+++ b/drivers/regulator/cpr3-regulator.h
@@ -735,6 +735,12 @@ struct cpr3_panic_regs_info {
  * @panic_notifier:	Notifier block registered to global panic notifier list.
  * @support_ldo300_vreg: Boolean value which indicates that this CPR controller
  *			manages an underlying LDO regulator of type LDO300.
+ * @reset_step_quot_loop_en: Boolean value which indicates that this CPR
+ *			controller should be configured to reset step_quot on
+ *			each loop_en = 0 transition. This configuration allows
+ *			the CPR controller to first use the default step_quot
+ *			and then later switch to the run-time calibrated
+ *			step_quot.
  *
  * This structure contains both configuration and runtime state data.  The
  * elements cpr_allowed_sw, use_hw_closed_loop, aggr_corner, cpr_enabled,
@@ -836,6 +842,7 @@ struct cpr3_controller {
 	struct cpr3_panic_regs_info *panic_regs_info;
 	struct notifier_block	panic_notifier;
 	bool			support_ldo300_vreg;
+	bool			reset_step_quot_loop_en;
 };
 
 /* Used for rounding voltages to the closest physically available set point. */
diff --git a/drivers/regulator/cpr3-util.c b/drivers/regulator/cpr3-util.c
index 0a1a1c56bd16..fcbaf9f5f51f 100644
--- a/drivers/regulator/cpr3-util.c
+++ b/drivers/regulator/cpr3-util.c
@@ -1221,6 +1221,14 @@ int cpr3_parse_common_ctrl_data(struct cpr3_controller *ctrl)
 	}
 
 	/*
+	 * Reset step_quot to default on each loop_en = 0 transition is
+	 * optional.
+	 */
+	ctrl->reset_step_quot_loop_en
+		= of_property_read_bool(ctrl->dev->of_node,
+					"qcom,cpr-reset-step-quot-loop-en");
+
+	/*
 	 * Regulator device handles are not necessary for CPRh controllers
 	 * since communication with the regulators is completely managed
 	 * in hardware.