[PATCH 1/2] regulator: anatop: Add power gating support to digital LDOs

[Philipp Zabel]

The ARM, PU, and SOC LDOs in the i.MX6 PMU can completely gate
their power output. Since power gating is configured by writing
zero to the voltage target bitfield,, store a copy of the
voltage selector to be restored when reenabling the regulator.

Signed-off-by: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
---
 drivers/regulator/anatop-regulator.c | 59 +++++++++++++++++++++++++++++++++++-
 1 file changed, 58 insertions(+), 1 deletion(-)

diff --git a/drivers/regulator/anatop-regulator.c b/drivers/regulator/anatop-regulator.c
index c734d09..93a6413 100644
--- a/drivers/regulator/anatop-regulator.c
+++ b/drivers/regulator/anatop-regulator.c
@@ -34,6 +34,8 @@
 #define LDO_RAMP_UP_UNIT_IN_CYCLES      64 /* 64 cycles per step */
 #define LDO_RAMP_UP_FREQ_IN_MHZ         24 /* cycle based on 24M OSC */
 
+#define LDO_POWER_GATE			0x00
+
 struct anatop_regulator {
 	const char *name;
 	u32 control_reg;
@@ -48,17 +50,28 @@ struct anatop_regulator {
 	int max_voltage;
 	struct regulator_desc rdesc;
 	struct regulator_init_data *initdata;
+	int sel;
 };
 
+static inline bool anatop_is_core_reg(struct anatop_regulator *anatop_reg)
+{
+	/* Only core regulators have the ramp up delay configuration. */
+	return anatop_reg->delay_bit_width;
+}
+
 static int anatop_regmap_set_voltage_sel(struct regulator_dev *reg,
 					unsigned selector)
 {
 	struct anatop_regulator *anatop_reg = rdev_get_drvdata(reg);
+	int ret;
 
 	if (!anatop_reg->control_reg)
 		return -ENOTSUPP;
 
-	return regulator_set_voltage_sel_regmap(reg, selector);
+	ret = regulator_set_voltage_sel_regmap(reg, selector);
+	if (!ret)
+		anatop_reg->sel = selector;
+	return ret;
 }
 
 static int anatop_regmap_set_voltage_time_sel(struct regulator_dev *reg,
@@ -97,7 +110,40 @@ static int anatop_regmap_get_voltage_sel(struct regulator_dev *reg)
 	return regulator_get_voltage_sel_regmap(reg);
 }
 
+static int anatop_regmap_enable(struct regulator_dev *reg)
+{
+	struct anatop_regulator *anatop_reg = rdev_get_drvdata(reg);
+
+	if (!anatop_is_core_reg(anatop_reg))
+		return 0;
+
+	return regulator_set_voltage_sel_regmap(reg, anatop_reg->sel);
+}
+
+static int anatop_regmap_disable(struct regulator_dev *reg)
+{
+	struct anatop_regulator *anatop_reg = rdev_get_drvdata(reg);
+
+	if (!anatop_is_core_reg(anatop_reg))
+		return -ENOTSUPP;
+
+	return regulator_set_voltage_sel_regmap(reg, LDO_POWER_GATE);
+}
+
+static int anatop_regmap_is_enabled(struct regulator_dev *reg)
+{
+	struct anatop_regulator *anatop_reg = rdev_get_drvdata(reg);
+
+	if (!anatop_is_core_reg(anatop_reg))
+		return 1;
+
+	return regulator_get_voltage_sel_regmap(reg) != LDO_POWER_GATE;
+}
+
 static struct regulator_ops anatop_rops = {
+	.enable = anatop_regmap_enable,
+	.disable = anatop_regmap_disable,
+	.is_enabled = anatop_regmap_is_enabled,
 	.set_voltage_sel = anatop_regmap_set_voltage_sel,
 	.set_voltage_time_sel = anatop_regmap_set_voltage_time_sel,
 	.get_voltage_sel = anatop_regmap_get_voltage_sel,
@@ -116,6 +162,7 @@ static int anatop_regulator_probe(struct platform_device *pdev)
 	struct regulator_init_data *initdata;
 	struct regulator_config config = { };
 	int ret = 0;
+	u32 val;
 
 	initdata = of_get_regulator_init_data(dev, np);
 	sreg = devm_kzalloc(dev, sizeof(*sreg), GFP_KERNEL);
@@ -199,6 +246,16 @@ static int anatop_regulator_probe(struct platform_device *pdev)
 	config.of_node = pdev->dev.of_node;
 	config.regmap = sreg->anatop;
 
+	if (sreg->control_reg && anatop_is_core_reg(sreg)) {
+		ret = regmap_read(config.regmap, rdesc->vsel_reg, &val);
+		if (ret) {
+			dev_err(dev, "failed to read initial state\n");
+			goto anatop_probe_end;
+		}
+
+		sreg->sel = (val & rdesc->vsel_mask) >> sreg->vol_bit_shift;
+	}
+
 	/* register regulator */
 	rdev = devm_regulator_register(dev, rdesc, &config);
 	if (IS_ERR(rdev)) {
-- 
1.8.5.3

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