[PATCH 1/3] regulator: max8973: Fix up control flag option for bias control

[PATCH 1/3] regulator: max8973: Fix up control flag option for bias control

[Laxman Dewangan]

The control flag for the bias control is MAX8973_CONTROL_BIAS_ENABLE
rather than MAX8973_BIAS_ENABLE which is macro for the bits in
register.

Fix this typo.

Signed-off-by: Laxman Dewangan <ldewangan-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
---
 drivers/regulator/max8973-regulator.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/regulator/max8973-regulator.c b/drivers/regulator/max8973-regulator.c
index 6f2bdad..e94ddcf 100644
--- a/drivers/regulator/max8973-regulator.c
+++ b/drivers/regulator/max8973-regulator.c
@@ -450,7 +450,7 @@ static struct max8973_regulator_platform_data *max8973_parse_dt(
 		pdata->control_flags  |= MAX8973_CONTROL_FREQ_SHIFT_9PER_ENABLE;
 
 	if (of_property_read_bool(np, "maxim,enable-bias-control"))
-		pdata->control_flags  |= MAX8973_BIAS_ENABLE;
+		pdata->control_flags  |= MAX8973_CONTROL_BIAS_ENABLE;
 
 	return pdata;
 }
-- 
2.1.4

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[PATCH 2/3] regulator: max8973: add support to configure ETR from DT

[Laxman Dewangan]

The MAX8973/MAX77621 feature an Enhanced Transient Response(ETR)
circuit that is enabled through software. The enhanced transient
response reduces the voltage droop during large load steps by
temporarily allowing all three phases to fire in unison, slewing
total inductor current faster than would normally be possible if
all three phases continued to operate 120deg out of phase. The
enhanced transient response detector features two selectable
sensitivity settings, which select the output voltage slew rate
during load transients that triggers the ETR circuit. The sensitivity
of the ETR detector is set by the CKADV[1:0] bits in the CONTROL2
register.

Add support to configure the ETR through platform data from DT.
Update the DT binding document accordingly.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
---
 .../bindings/regulator/max8973-regulator.txt          |  6 ++++++
 drivers/regulator/max8973-regulator.c                 | 19 +++++++++++++++++++
 2 files changed, 25 insertions(+)

diff --git a/Documentation/devicetree/bindings/regulator/max8973-regulator.txt b/Documentation/devicetree/bindings/regulator/max8973-regulator.txt
index 55efb24..f80ea2f 100644
--- a/Documentation/devicetree/bindings/regulator/max8973-regulator.txt
+++ b/Documentation/devicetree/bindings/regulator/max8973-regulator.txt
@@ -25,6 +25,12 @@ Optional properties:
 -maxim,enable-frequency-shift: boolean, enable 9% frequency shift.
 -maxim,enable-bias-control: boolean, enable bias control. By enabling this
 		startup delay can be reduce to 20us from 220us.
+-maxim,enable-etr: boolean, enable Enhanced Transient Response.
+-maxim,enable-high-etr-sensitivity: boolean, Enhanced transient response
+		circuit is enabled and set for high sensitivity. If this
+		property is available then etr will be enable default.
+
+Enhanced transient response (ETR) will affect the configuration of CKADV.
 
 Example:
 
diff --git a/drivers/regulator/max8973-regulator.c b/drivers/regulator/max8973-regulator.c
index e94ddcf..a8fd7f4 100644
--- a/drivers/regulator/max8973-regulator.c
+++ b/drivers/regulator/max8973-regulator.c
@@ -421,6 +421,8 @@ static struct max8973_regulator_platform_data *max8973_parse_dt(
 	struct device_node *np = dev->of_node;
 	int ret;
 	u32 pval;
+	bool etr_enable;
+	bool etr_sensitivity_high;
 
 	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
 	if (!pdata)
@@ -452,6 +454,23 @@ static struct max8973_regulator_platform_data *max8973_parse_dt(
 	if (of_property_read_bool(np, "maxim,enable-bias-control"))
 		pdata->control_flags  |= MAX8973_CONTROL_BIAS_ENABLE;
 
+	etr_enable = of_property_read_bool(np, "maxim,enable-etr");
+	etr_sensitivity_high = of_property_read_bool(np,
+				"maxim,enable-high-etr-sensitivity");
+	if (etr_sensitivity_high)
+		etr_enable = true;
+
+	if (etr_enable) {
+		if (etr_sensitivity_high)
+			pdata->control_flags |=
+				MAX8973_CONTROL_CLKADV_TRIP_75mV_PER_US;
+		else
+			pdata->control_flags |=
+				MAX8973_CONTROL_CLKADV_TRIP_150mV_PER_US;
+	} else {
+		pdata->control_flags |= MAX8973_CONTROL_CLKADV_TRIP_DISABLED;
+	}
+
 	return pdata;
 }
 
-- 
2.1.4

[PATCH 3/3] regulator: max8973: add support to configure ETR based on rail load

[Laxman Dewangan]

Add support to configure Enhanced Transient Response Enable (ETR)
and Sensitivity Selection based on maximum current i.e. expected
load on that rail.

Maxim recommended as:
- Enable ETR with high sensitivity (75mV/us) for 0 to 9A expected loads,
- Enable ETR with low sensitivity (150mV/us) for 9A to 12A expected loads.
- Disable ETR for expected load > 12A.

These recommendation will be configured for MAX77621 when maximum load
is provided through regulator constraint for maximum current from platform.

Signed-off-by: Laxman Dewangan <ldewangan-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
---
 drivers/regulator/max8973-regulator.c | 52 +++++++++++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)

diff --git a/drivers/regulator/max8973-regulator.c b/drivers/regulator/max8973-regulator.c
index a8fd7f4..f673659 100644
--- a/drivers/regulator/max8973-regulator.c
+++ b/drivers/regulator/max8973-regulator.c
@@ -75,6 +75,7 @@
 #define MAX8973_DISCH_ENBABLE				BIT(5)
 #define MAX8973_FT_ENABLE				BIT(4)
 
+#define MAX8973_CKKADV_TRIP_MASK			0xC
 #define MAX8973_CKKADV_TRIP_DISABLE			0xC
 #define MAX8973_CKKADV_TRIP_75mV_PER_US			0x0
 #define MAX8973_CKKADV_TRIP_150mV_PER_US		0x4
@@ -282,6 +283,55 @@ static int max8973_set_ramp_delay(struct regulator_dev *rdev,
 	return ret;
 }
 
+static int max8973_set_current_limit(struct regulator_dev *rdev,
+		int min_ua, int max_ua)
+{
+	struct max8973_chip *max = rdev_get_drvdata(rdev);
+	unsigned int val;
+	int ret;
+
+	if (max_ua <= 9000000)
+		val = MAX8973_CKKADV_TRIP_75mV_PER_US;
+	else if (max_ua <= 12000000)
+		val = MAX8973_CKKADV_TRIP_150mV_PER_US;
+	else
+		val = MAX8973_CKKADV_TRIP_DISABLE;
+
+	ret = regmap_update_bits(max->regmap, MAX8973_CONTROL2,
+			MAX8973_CKKADV_TRIP_MASK, val);
+	if (ret < 0) {
+		dev_err(max->dev, "register %d update failed: %d\n",
+				MAX8973_CONTROL2, ret);
+		return ret;
+	}
+	return 0;
+}
+
+static int max8973_get_current_limit(struct regulator_dev *rdev)
+{
+	struct max8973_chip *max = rdev_get_drvdata(rdev);
+	unsigned int control2;
+	int ret;
+
+	ret = regmap_read(max->regmap, MAX8973_CONTROL2, &control2);
+	if (ret < 0) {
+		dev_err(max->dev, "register %d read failed: %d\n",
+				MAX8973_CONTROL2, ret);
+		return ret;
+	}
+	switch (control2 & MAX8973_CKKADV_TRIP_MASK) {
+	case MAX8973_CKKADV_TRIP_DISABLE:
+		return 15000000;
+	case MAX8973_CKKADV_TRIP_150mV_PER_US:
+		return 12000000;
+	case MAX8973_CKKADV_TRIP_75mV_PER_US:
+		return 9000000;
+	default:
+		break;
+	}
+	return 9000000;
+}
+
 static const struct regulator_ops max8973_dcdc_ops = {
 	.get_voltage_sel	= max8973_dcdc_get_voltage_sel,
 	.set_voltage_sel	= max8973_dcdc_set_voltage_sel,
@@ -632,6 +682,8 @@ static int max8973_probe(struct i2c_client *client,
 		max->ops.enable = regulator_enable_regmap;
 		max->ops.disable = regulator_disable_regmap;
 		max->ops.is_enabled = regulator_is_enabled_regmap;
+		max->ops.set_current_limit = max8973_set_current_limit;
+		max->ops.get_current_limit = max8973_get_current_limit;
 		break;
 	default:
 		break;
-- 
2.1.4

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