regulator: twl: Fix list_voltate for twl6030ldo_ops

According to the datasheet, the voltage for twl6030ldo_ops is not linear for
all cases. Linear mapping is only for the selection code from
00000001 to 00011000.

Table 9. LDO Output Voltage Selection Code
CODE     VOUT(V)    COD      VOUT(V)    CODE     VOUT(V)    CODE     VOUT(V)
00000000 0          00001000 1.7        00010000 2.5        00011000 3.3
00000001 1.0        00001001 1.8        00010001 2.6        00011001 Reserved
00000010 1.1        00001010 1.9        00010010 2.7        00011010 Reserved
00000011 1.2        00001011 2.0        00010011 2.8        00011011 Reserved
00000100 1.3        00001100 2.1        00010100 2.9        00011100 Reserved
00000101 1.4        00001101 2.2        00010101 3.0        00011101 Reserved
00000110 1.5        00001110 2.3        00010110 3.1        00011110 Reserved
00000111 1.6        00001111 2.4        00010111 3.2        00011111 2.75

This patch implements the list_voltage callback based on above table.
Signed-off-by: Axel Lin <axel.lin@gmail.com>
Tested-by: Rajendra Nayak <rnayak@ti.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

drivers/regulator/twl-regulator.c

@@ -559,6 +559,27 @@ static struct regulator_ops twl6030coresmps_ops = {
 	.get_voltage	= twl6030coresmps_get_voltage,
 };
 
+static int twl6030ldo_list_voltage(struct regulator_dev *rdev, unsigned sel)
+{
+	struct twlreg_info *info = rdev_get_drvdata(rdev);
+
+	switch (sel) {
+	case 0:
+		return 0;
+	case 1 ... 24:
+		/* Linear mapping from 00000001 to 00011000:
+		 * Absolute voltage value = 1.0 V + 0.1 V × (sel – 00000001)
+		 */
+		return (info->min_mV + 100 * (sel - 1)) * 1000;
+	case 25 ... 30:
+		return -EINVAL;
+	case 31:
+		return 2750000;
+	default:
+		return -EINVAL;
+	}
+}
+
 static int
 twl6030ldo_set_voltage_sel(struct regulator_dev *rdev, unsigned selector)
 {
@@ -577,7 +598,7 @@ static int twl6030ldo_get_voltage_sel(struct regulator_dev *rdev)
 }
 
 static struct regulator_ops twl6030ldo_ops = {
-	.list_voltage	= regulator_list_voltage_linear,
+	.list_voltage	= twl6030ldo_list_voltage,
 
 	.set_voltage_sel = twl6030ldo_set_voltage_sel,
 	.get_voltage_sel = twl6030ldo_get_voltage_sel,
@@ -906,12 +927,10 @@ static struct twlreg_info TWL6030_INFO_##label = { \
 	.desc = { \
 		.name = #label, \
 		.id = TWL6030_REG_##label, \
-		.n_voltages = (max_mVolts - min_mVolts)/100 + 1, \
+		.n_voltages = 32, \
 		.ops = &twl6030ldo_ops, \
 		.type = REGULATOR_VOLTAGE, \
 		.owner = THIS_MODULE, \
-		.min_uV = min_mVolts * 1000, \
-		.uV_step = 100 * 1000, \
 		}, \
 	}
 
@@ -923,12 +942,10 @@ static struct twlreg_info TWL6025_INFO_##label = { \
 	.desc = { \
 		.name = #label, \
 		.id = TWL6025_REG_##label, \
-		.n_voltages = ((max_mVolts - min_mVolts)/100) + 1, \
+		.n_voltages = 32, \
 		.ops = &twl6030ldo_ops, \
 		.type = REGULATOR_VOLTAGE, \
 		.owner = THIS_MODULE, \
-		.min_uV = min_mVolts * 1000, \
-		.uV_step = 100 * 1000, \
 		}, \
 	}