regulator: mcp16502: add support for ramp delay

MCP16502 have configurable ramp delay support (via DVSR bits in
regulators' CFG register).

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>

drivers/regulator/mcp16502.c

@@ -22,8 +22,9 @@
 #define VDD_LOW_SEL 0x0D
 #define VDD_HIGH_SEL 0x3F
 
-#define MCP16502_FLT BIT(7)
-#define MCP16502_ENS BIT(0)
+#define MCP16502_FLT		BIT(7)
+#define MCP16502_DVSR		GENMASK(3, 2)
+#define MCP16502_ENS		BIT(0)
 
 /*
  * The PMIC has four sets of registers corresponding to four power modes:
@@ -88,6 +89,12 @@ enum mcp16502_reg {
 	MCP16502_REG_CFG,
 };
 
+/* Ramp delay (uV/us) for buck1, ldo1, ldo2. */
+static const int mcp16502_ramp_b1l12[] = { 6250, 3125, 2083, 1563 };
+
+/* Ramp delay (uV/us) for buck2, buck3, buck4. */
+static const int mcp16502_ramp_b234[] = { 3125, 1563, 1042, 781 };
+
 static unsigned int mcp16502_of_map_mode(unsigned int mode)
 {
 	if (mode == REGULATOR_MODE_NORMAL || mode == REGULATOR_MODE_IDLE)
@@ -271,6 +278,80 @@ static int mcp16502_get_status(struct regulator_dev *rdev)
 	return REGULATOR_STATUS_UNDEFINED;
 }
 
+static int mcp16502_set_voltage_time_sel(struct regulator_dev *rdev,
+					 unsigned int old_sel,
+					 unsigned int new_sel)
+{
+	static const u8 us_ramp[] = { 8, 16, 24, 32 };
+	int id = rdev_get_id(rdev);
+	unsigned int uV_delta, val;
+	int ret;
+
+	ret = regmap_read(rdev->regmap, MCP16502_REG_BASE(id, CFG), &val);
+	if (ret)
+		return ret;
+
+	val = (val & MCP16502_DVSR) >> 2;
+	uV_delta = abs(new_sel * rdev->desc->linear_ranges->uV_step -
+		       old_sel * rdev->desc->linear_ranges->uV_step);
+	switch (id) {
+	case BUCK1:
+	case LDO1:
+	case LDO2:
+		ret = DIV_ROUND_CLOSEST(uV_delta * us_ramp[val],
+					mcp16502_ramp_b1l12[val]);
+		break;
+
+	case BUCK2:
+	case BUCK3:
+	case BUCK4:
+		ret = DIV_ROUND_CLOSEST(uV_delta * us_ramp[val],
+					mcp16502_ramp_b234[val]);
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	return ret;
+}
+
+static int mcp16502_set_ramp_delay(struct regulator_dev *rdev, int ramp_delay)
+{
+	const int *ramp;
+	int id = rdev_get_id(rdev);
+	unsigned int i, size;
+
+	switch (id) {
+	case BUCK1:
+	case LDO1:
+	case LDO2:
+		ramp = mcp16502_ramp_b1l12;
+		size = ARRAY_SIZE(mcp16502_ramp_b1l12);
+		break;
+
+	case BUCK2:
+	case BUCK3:
+	case BUCK4:
+		ramp = mcp16502_ramp_b234;
+		size = ARRAY_SIZE(mcp16502_ramp_b234);
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	for (i = 0; i < size; i++) {
+		if (ramp[i] == ramp_delay)
+			break;
+	}
+	if (i == size)
+		return -EINVAL;
+
+	return regmap_update_bits(rdev->regmap, MCP16502_REG_BASE(id, CFG),
+				  MCP16502_DVSR, (i << 2));
+}
+
 #ifdef CONFIG_SUSPEND
 /*
  * mcp16502_suspend_get_target_reg() - get the reg of the target suspend PMIC
@@ -365,6 +446,8 @@ static const struct regulator_ops mcp16502_buck_ops = {
 	.disable			= regulator_disable_regmap,
 	.is_enabled			= regulator_is_enabled_regmap,
 	.get_status			= mcp16502_get_status,
+	.set_voltage_time_sel		= mcp16502_set_voltage_time_sel,
+	.set_ramp_delay			= mcp16502_set_ramp_delay,
 
 	.set_mode			= mcp16502_set_mode,
 	.get_mode			= mcp16502_get_mode,
@@ -389,6 +472,8 @@ static const struct regulator_ops mcp16502_ldo_ops = {
 	.disable			= regulator_disable_regmap,
 	.is_enabled			= regulator_is_enabled_regmap,
 	.get_status			= mcp16502_get_status,
+	.set_voltage_time_sel		= mcp16502_set_voltage_time_sel,
+	.set_ramp_delay			= mcp16502_set_ramp_delay,
 
 #ifdef CONFIG_SUSPEND
 	.set_suspend_voltage		= mcp16502_set_suspend_voltage,