drm/msm/dsi: Fix regulator API abuse

The voltage changing code in this driver is broken and should be
removed.  The driver sets a single, exact voltage on probe.  Unless
there is a very good reason for this (which should be documented in
comments) constraints like this need to be set via the machine
constraints, voltage setting in a driver is expected to be used in cases
where the voltage varies at runtime.

In addition client drivers should almost never be calling
regulator_can_set_voltage(), if the device needs to set a voltage it
needs to set the voltage and the regulator core will handle the case
where the regulator is fixed voltage.  If the driver simply skips
setting the voltage if it doesn't have permission then it should just
not bother in the first place.

Originally authored by Mark Brown <broonie@kernel.org>

Remove the min/max voltage data entries per SoC managed by the driver.
These aren't needed as we don't try to set voltages any more. Mention in
comments the voltages that each regulator expects.
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@gmail.com>

drivers/gpu/drm/msm/dsi/dsi.h

@@ -41,8 +41,6 @@ enum msm_dsi_phy_type {
 /* Regulators for DSI devices */
 struct dsi_reg_entry {
 	char name[32];
-	int min_voltage;
-	int max_voltage;
 	int enable_load;
 	int disable_load;
 };

drivers/gpu/drm/msm/dsi/dsi_cfg.c

@@ -22,9 +22,9 @@ static const struct msm_dsi_config apq8064_dsi_cfg = {
 	.reg_cfg = {
 		.num = 3,
 		.regs = {
-			{"vdda", 1200000, 1200000, 100000, 100},
-			{"avdd", 3000000, 3000000, 110000, 100},
-			{"vddio", 1800000, 1800000, 100000, 100},
+			{"vdda", 100000, 100},	/* 1.2 V */
+			{"avdd", 10000, 100},	/* 3.0 V */
+			{"vddio", 100000, 100},	/* 1.8 V */
 		},
 	},
 	.bus_clk_names = dsi_v2_bus_clk_names,
@@ -40,10 +40,10 @@ static const struct msm_dsi_config msm8974_apq8084_dsi_cfg = {
 	.reg_cfg = {
 		.num = 4,
 		.regs = {
-			{"gdsc", -1, -1, -1, -1},
-			{"vdd", 3000000, 3000000, 150000, 100},
-			{"vdda", 1200000, 1200000, 100000, 100},
-			{"vddio", 1800000, 1800000, 100000, 100},
+			{"gdsc", -1, -1},
+			{"vdd", 150000, 100},	/* 3.0 V */
+			{"vdda", 100000, 100},	/* 1.2 V */
+			{"vddio", 100000, 100},	/* 1.8 V */
 		},
 	},
 	.bus_clk_names = dsi_6g_bus_clk_names,
@@ -59,9 +59,9 @@ static const struct msm_dsi_config msm8916_dsi_cfg = {
 	.reg_cfg = {
 		.num = 3,
 		.regs = {
-			{"gdsc", -1, -1, -1, -1},
-			{"vdda", 1200000, 1200000, 100000, 100},
-			{"vddio", 1800000, 1800000, 100000, 100},
+			{"gdsc", -1, -1},
+			{"vdda", 100000, 100},	/* 1.2 V */
+			{"vddio", 100000, 100},	/* 1.8 V */
 		},
 	},
 	.bus_clk_names = dsi_8916_bus_clk_names,
@@ -73,13 +73,13 @@ static const struct msm_dsi_config msm8994_dsi_cfg = {
 	.reg_cfg = {
 		.num = 7,
 		.regs = {
-			{"gdsc", -1, -1, -1, -1},
-			{"vdda", 1250000, 1250000, 100000, 100},
-			{"vddio", 1800000, 1800000, 100000, 100},
-			{"vcca", 1000000, 1000000, 10000, 100},
-			{"vdd", 1800000, 1800000, 100000, 100},
-			{"lab_reg", -1, -1, -1, -1},
-			{"ibb_reg", -1, -1, -1, -1},
+			{"gdsc", -1, -1},
+			{"vdda", 100000, 100},	/* 1.25 V */
+			{"vddio", 100000, 100},	/* 1.8 V */
+			{"vcca", 10000, 100},	/* 1.0 V */
+			{"vdd", 100000, 100},	/* 1.8 V */
+			{"lab_reg", -1, -1},
+			{"ibb_reg", -1, -1},
 		},
 	},
 	.bus_clk_names = dsi_6g_bus_clk_names,

drivers/gpu/drm/msm/dsi/dsi_host.c

@@ -325,18 +325,6 @@ static int dsi_regulator_init(struct msm_dsi_host *msm_host)
 		return ret;
 	}
 
-	for (i = 0; i < num; i++) {
-		if (regulator_can_change_voltage(s[i].consumer)) {
-			ret = regulator_set_voltage(s[i].consumer,
-				regs[i].min_voltage, regs[i].max_voltage);
-			if (ret < 0) {
-				pr_err("regulator %d set voltage failed, %d\n",
-					i, ret);
-				return ret;
-			}
-		}
-	}
-
 	return 0;
 }
 

drivers/gpu/drm/msm/dsi/phy/dsi_phy.c

@@ -177,19 +177,6 @@ static int dsi_phy_regulator_init(struct msm_dsi_phy *phy)
 		return ret;
 	}
 
-	for (i = 0; i < num; i++) {
-		if (regulator_can_change_voltage(s[i].consumer)) {
-			ret = regulator_set_voltage(s[i].consumer,
-				regs[i].min_voltage, regs[i].max_voltage);
-			if (ret < 0) {
-				dev_err(dev,
-					"regulator %d set voltage failed, %d\n",
-					i, ret);
-				return ret;
-			}
-		}
-	}
-
 	return 0;
 }
 

drivers/gpu/drm/msm/dsi/phy/dsi_phy_20nm.c

@@ -138,8 +138,8 @@ const struct msm_dsi_phy_cfg dsi_phy_20nm_cfgs = {
 	.reg_cfg = {
 		.num = 2,
 		.regs = {
-			{"vddio", 1800000, 1800000, 100000, 100},
-			{"vcca", 1000000, 1000000, 10000, 100},
+			{"vddio", 100000, 100},	/* 1.8 V */
+			{"vcca", 10000, 100},	/* 1.0 V */
 		},
 	},
 	.ops = {

drivers/gpu/drm/msm/dsi/phy/dsi_phy_28nm.c

@@ -138,7 +138,7 @@ const struct msm_dsi_phy_cfg dsi_phy_28nm_hpm_cfgs = {
 	.reg_cfg = {
 		.num = 1,
 		.regs = {
-			{"vddio", 1800000, 1800000, 100000, 100},
+			{"vddio", 100000, 100},
 		},
 	},
 	.ops = {
@@ -153,7 +153,7 @@ const struct msm_dsi_phy_cfg dsi_phy_28nm_lp_cfgs = {
 	.reg_cfg = {
 		.num = 1,
 		.regs = {
-			{"vddio", 1800000, 1800000, 100000, 100},
+			{"vddio", 100000, 100},	/* 1.8 V */
 		},
 	},
 	.ops = {

drivers/gpu/drm/msm/dsi/phy/dsi_phy_28nm_8960.c

@@ -185,7 +185,7 @@ const struct msm_dsi_phy_cfg dsi_phy_28nm_8960_cfgs = {
 	.reg_cfg = {
 		.num = 1,
 		.regs = {
-			{"vddio", 1800000, 1800000, 100000, 100},
+			{"vddio", 100000, 100},	/* 1.8 V */
 		},
 	},
 	.ops = {