msm: mdss: update voltage level configuration for CX supply

Read the minimum and the maximum voltage levels for the CX supply
from the device tree and use those values to program the CX supply.
This allows for flexibility in configuring the levels across
multiple targets.

CRs-Fixed: 1053687
Change-Id: Ib704bfa6c6ca9fc3d90ab76a2e4aef02dc48822a
Signed-off-by: Aravind Venkateswaran <aravindh@codeaurora.org>

Documentation/devicetree/bindings/fb/mdss-mdp.txt

@@ -243,6 +243,12 @@ Bus Scaling Data:
 Optional properties:
 - batfet-supply :	Phandle for battery FET regulator device node.
 - vdd-cx-supply :	Phandle for vdd CX regulator device node.
+- vdd-cx-min-uV :	The minimum voltage level in uV for the CX rail
+			whenever the display is on. If vdd-cx-supply is
+			specified, then this binding is mandatory.
+- vdd-cx-max-uV :	The maximum voltage level in uV for the CX rail
+			whenever the display is on. If vdd-cx-supply is
+			specified, then this binding is mandatory.
 - qcom,vbif-settings :	Array with key-value pairs of constant VBIF register
 			settings used to setup MDSS QoS for optimum performance.
 			The key used should be offset from "vbif_phys" register

drivers/video/fbdev/msm/mdss.h

@@ -277,6 +277,8 @@ struct mdss_data_type {
 	struct regulator *fs;
 	struct regulator *venus;
 	struct regulator *vdd_cx;
+	u32 vdd_cx_min_uv;
+	u32 vdd_cx_max_uv;
 	bool batfet_required;
 	struct regulator *batfet;
 	bool en_svs_high;

drivers/video/fbdev/msm/mdss_mdp.c

@@ -1703,6 +1703,24 @@ static int mdss_mdp_irq_clk_setup(struct mdss_data_type *mdata)
 		pr_debug("unable to get CX reg. rc=%d\n",
 					PTR_RET(mdata->vdd_cx));
 		mdata->vdd_cx = NULL;
+	} else {
+		/* Parse CX voltage settings */
+		ret = of_property_read_u32(mdata->pdev->dev.of_node,
+			"vdd-cx-min-uV", &mdata->vdd_cx_min_uv);
+		if (ret) {
+			pr_err("min uV for vdd-cx not specified. rc=%d\n", ret);
+			return ret;
+		}
+
+		ret = of_property_read_u32(mdata->pdev->dev.of_node,
+			"vdd-cx-max-uV", &mdata->vdd_cx_max_uv);
+		if (ret) {
+			pr_err("max uV for vdd-cx not specified. rc=%d\n", ret);
+			return ret;
+		}
+
+		pr_debug("vdd_cx [min_uV, max_uV] = [%d %d]\n",
+			mdata->vdd_cx_min_uv, mdata->vdd_cx_max_uv);
 	}
 
 	mdata->reg_bus_clt = mdss_reg_bus_vote_client_create("mdp\0");
@@ -4744,8 +4762,8 @@ static int mdss_mdp_cx_ctrl(struct mdss_data_type *mdata, int enable)
 	if (enable) {
 		rc = regulator_set_voltage(
 				mdata->vdd_cx,
-				RPM_REGULATOR_CORNER_SVS_SOC,
+				mdata->vdd_cx_min_uv,
-				RPM_REGULATOR_CORNER_SUPER_TURBO);
+				mdata->vdd_cx_max_uv);
 		if (rc < 0)
 			goto vreg_set_voltage_fail;
 
@@ -4764,8 +4782,8 @@ static int mdss_mdp_cx_ctrl(struct mdss_data_type *mdata, int enable)
 		}
 		rc = regulator_set_voltage(
 				mdata->vdd_cx,
-				RPM_REGULATOR_CORNER_NONE,
+				0,
-				RPM_REGULATOR_CORNER_SUPER_TURBO);
+				mdata->vdd_cx_max_uv);
 		if (rc < 0)
 			goto vreg_set_voltage_fail;
 	}