[PATCH v3 1/2] regulator: anatop: Add power gating support to digital LDOs

[Philipp Zabel <p.zabel@pengutronix.de>]

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@pengutronix.de>
---
Changes since v2:
 - Rebased against v3.14-rc2, the anatop_probe_end jump label
   was removed.
---
 drivers/regulator/anatop-regulator.c | 76 +++++++++++++++++++++++++++++++++++-
 1 file changed, 74 insertions(+), 2 deletions(-)

diff --git a/drivers/regulator/anatop-regulator.c b/drivers/regulator/anatop-regulator.c
index 862e63e..dff120a 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;
@@ -48,6 +50,7 @@ struct anatop_regulator {
 	int max_voltage;
 	struct regulator_desc rdesc;
 	struct regulator_init_data *initdata;
+	int sel;
 };
 
 static int anatop_regmap_set_voltage_sel(struct regulator_dev *reg,
@@ -97,14 +100,68 @@ 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);
+
+	return regulator_set_voltage_sel_regmap(reg, anatop_reg->sel);
+}
+
+static int anatop_regmap_disable(struct regulator_dev *reg)
+{
+	return regulator_set_voltage_sel_regmap(reg, LDO_POWER_GATE);
+}
+
+static int anatop_regmap_is_enabled(struct regulator_dev *reg)
+{
+	return regulator_get_voltage_sel_regmap(reg) != LDO_POWER_GATE;
+}
+
+static int anatop_regmap_core_set_voltage_sel(struct regulator_dev *reg,
+					      unsigned selector)
+{
+	struct anatop_regulator *anatop_reg = rdev_get_drvdata(reg);
+	int ret;
+
+	if (!anatop_regmap_is_enabled(reg)) {
+		anatop_reg->sel = selector;
+		return 0;
+	}
+
+	ret = regulator_set_voltage_sel_regmap(reg, selector);
+	if (!ret)
+		anatop_reg->sel = selector;
+	return ret;
+}
+
+static int anatop_regmap_core_get_voltage_sel(struct regulator_dev *reg)
+{
+	struct anatop_regulator *anatop_reg = rdev_get_drvdata(reg);
+
+	if (!anatop_regmap_is_enabled(reg))
+		return anatop_reg->sel;
+
+	return regulator_get_voltage_sel_regmap(reg);
+}
+
 static struct regulator_ops anatop_rops = {
 	.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,
 	.list_voltage = regulator_list_voltage_linear,
 	.map_voltage = regulator_map_voltage_linear,
 };
 
+static struct regulator_ops anatop_core_rops = {
+	.enable = anatop_regmap_enable,
+	.disable = anatop_regmap_disable,
+	.is_enabled = anatop_regmap_is_enabled,
+	.set_voltage_sel = anatop_regmap_core_set_voltage_sel,
+	.set_voltage_time_sel = anatop_regmap_set_voltage_time_sel,
+	.get_voltage_sel = anatop_regmap_core_get_voltage_sel,
+	.list_voltage = regulator_list_voltage_linear,
+	.map_voltage = regulator_map_voltage_linear,
+};
+
 static int anatop_regulator_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -116,6 +173,7 @@ 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);
@@ -125,7 +183,6 @@ static int anatop_regulator_probe(struct platform_device *pdev)
 	sreg->name = of_get_property(np, "regulator-name", NULL);
 	rdesc = &sreg->rdesc;
 	rdesc->name = sreg->name;
-	rdesc->ops = &anatop_rops;
 	rdesc->type = REGULATOR_VOLTAGE;
 	rdesc->owner = THIS_MODULE;
 
@@ -197,6 +254,21 @@ static int anatop_regulator_probe(struct platform_device *pdev)
 	config.of_node = pdev->dev.of_node;
 	config.regmap = sreg->anatop;
 
+	/* Only core regulators have the ramp up delay configuration. */
+	if (sreg->control_reg && sreg->delay_bit_width) {
+		rdesc->ops = &anatop_core_rops;
+
+		ret = regmap_read(config.regmap, rdesc->vsel_reg, &val);
+		if (ret) {
+			dev_err(dev, "failed to read initial state\n");
+			return ret;
+		}
+
+		sreg->sel = (val & rdesc->vsel_mask) >> sreg->vol_bit_shift;
+	} else {
+		rdesc->ops = &anatop_rops;
+	}
+
 	/* register regulator */
 	rdev = devm_regulator_register(dev, rdesc, &config);
 	if (IS_ERR(rdev)) {
-- 
1.8.5.3