Applied "regulator: pwm-regulator: Add support for continuous-voltage" to the regulator tree

[Mark Brown <broonie@kernel.org>]

The patch

   regulator: pwm-regulator: Add support for continuous-voltage

has been applied to the regulator tree at

   git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regulator.git 

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

>From 4773be185a0f7c1c09d8966e100c76f4fa9a3227 Mon Sep 17 00:00:00 2001
From: Lee Jones <lee.jones@linaro.org>
Date: Tue, 7 Jul 2015 16:06:51 +0100
Subject: [PATCH] regulator: pwm-regulator: Add support for continuous-voltage

The current version of PWM regulator only supports a static table
approach, where pre-calculated values are supplied by the vendor and
obtained via DT.  The continuous-voltage method takes min_uV and
max_uV, and divides the difference between them up into a number of
slices.  The number of slices depend on how large the duty cycle
register is.  This information is provided by a DT property.

As the name alludes, this provides values for a continuous voltage
range between min_uV and max_uV, which has obvious benefits over
either limited voltage possibilities, or the requirement to provide
a large voltage-table.

Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 drivers/regulator/pwm-regulator.c | 114 +++++++++++++++++++++++++++++++++++---
 1 file changed, 106 insertions(+), 8 deletions(-)

diff --git a/drivers/regulator/pwm-regulator.c b/drivers/regulator/pwm-regulator.c
index 25560fc519b7..dac145db305c 100644
--- a/drivers/regulator/pwm-regulator.c
+++ b/drivers/regulator/pwm-regulator.c
@@ -10,6 +10,7 @@
  * published by the Free Software Foundation.
  */
 
+#include <linux/delay.h>
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/err.h>
@@ -21,9 +22,16 @@
 #include <linux/pwm.h>
 
 struct pwm_regulator_data {
-	struct pwm_voltages *duty_cycle_table;
+	/*  Shared */
 	struct pwm_device *pwm;
+
+	/* Voltage table */
+	struct pwm_voltages *duty_cycle_table;
 	int state;
+
+	/* Continuous voltage */
+	u32 max_duty_cycle;
+	int volt_uV;
 };
 
 struct pwm_voltages {
@@ -31,6 +39,9 @@ struct pwm_voltages {
 	unsigned int dutycycle;
 };
 
+/**
+ * Voltage table call-backs
+ */
 static int pwm_regulator_get_voltage_sel(struct regulator_dev *rdev)
 {
 	struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
@@ -78,6 +89,71 @@ static int pwm_regulator_list_voltage(struct regulator_dev *rdev,
 
 	return drvdata->duty_cycle_table[selector].uV;
 }
+
+/**
+ * Continuous voltage call-backs
+ */
+static int pwm_voltage_to_duty_cycle(struct regulator_dev *rdev,
+					int volt_mV)
+{
+	struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
+	int min_mV = rdev->constraints->min_uV / 1000;
+	int max_mV = rdev->constraints->max_uV / 1000;
+	int max_duty_cycle = drvdata->max_duty_cycle;
+	int vdiff = min_mV - max_mV;
+	int pwm_code;
+	int tmp;
+
+	tmp = ((max_duty_cycle - min_mV) * max_duty_cycle) / vdiff;
+	pwm_code = ((tmp + max_duty_cycle) * volt_mV) / vdiff;
+
+	if (pwm_code < 0)
+		pwm_code = 0;
+	if (pwm_code > max_duty_cycle)
+		pwm_code = max_duty_cycle;
+
+	return pwm_code * 100 / max_duty_cycle;
+}
+
+static int pwm_regulator_get_voltage(struct regulator_dev *rdev)
+{
+	struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
+
+	return drvdata->volt_uV;
+}
+
+static int pwm_regulator_set_voltage(struct regulator_dev *rdev,
+					int min_uV, int max_uV,
+					unsigned *selector)
+{
+	struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
+	unsigned int ramp_delay = rdev->constraints->ramp_delay;
+	int duty_cycle;
+	int ret;
+
+	duty_cycle = pwm_voltage_to_duty_cycle(rdev, min_uV / 1000);
+
+	ret = pwm_config(drvdata->pwm,
+			 (drvdata->pwm->period / 100) * duty_cycle,
+			 drvdata->pwm->period);
+	if (ret) {
+		dev_err(&rdev->dev, "Failed to configure PWM\n");
+		return ret;
+	}
+
+	ret = pwm_enable(drvdata->pwm);
+	if (ret) {
+		dev_err(&rdev->dev, "Failed to enable PWM\n");
+		return ret;
+	}
+	drvdata->volt_uV = min_uV;
+
+	/* Delay required by PWM regulator to settle to the new voltage */
+	usleep_range(ramp_delay, ramp_delay + 1000);
+
+	return 0;
+}
+
 static struct regulator_ops pwm_regulator_voltage_table_ops = {
 	.set_voltage_sel = pwm_regulator_set_voltage_sel,
 	.get_voltage_sel = pwm_regulator_get_voltage_sel,
@@ -85,6 +161,11 @@ static struct regulator_ops pwm_regulator_voltage_table_ops = {
 	.map_voltage     = regulator_map_voltage_iterate,
 };
 
+static struct regulator_ops pwm_regulator_voltage_continuous_ops = {
+	.get_voltage = pwm_regulator_get_voltage,
+	.set_voltage = pwm_regulator_set_voltage,
+};
+
 static struct regulator_desc pwm_regulator_desc = {
 	.name		= "pwm-regulator",
 	.type		= REGULATOR_VOLTAGE,
@@ -129,6 +210,25 @@ static int pwm_regulator_init_table(struct platform_device *pdev,
 	return 0;
 }
 
+static int pwm_regulator_init_continuous(struct platform_device *pdev,
+					 struct pwm_regulator_data *drvdata)
+{
+	struct device_node *np = pdev->dev.of_node;
+	int ret;
+
+	ret = of_property_read_u32(np, "max-duty-cycle",
+				   &drvdata->max_duty_cycle);
+	if (ret) {
+		dev_err(&pdev->dev, "Failed to read \"pwm-max-value\"\n");
+		return ret;
+	}
+
+	pwm_regulator_desc.ops = &pwm_regulator_voltage_continuous_ops;
+	pwm_regulator_desc.continuous_voltage_range = true;
+
+	return 0;
+}
+
 static int pwm_regulator_probe(struct platform_device *pdev)
 {
 	struct pwm_regulator_data *drvdata;
@@ -146,14 +246,12 @@ static int pwm_regulator_probe(struct platform_device *pdev)
 	if (!drvdata)
 		return -ENOMEM;
 
-	if (of_find_property(np, "voltage-table", NULL)) {
+	if (of_find_property(np, "voltage-table", NULL))
 		ret = pwm_regulator_init_table(pdev, drvdata);
-		if (ret)
-			return ret;
-	} else {
-		dev_err(&pdev->dev, "No \"voltage-table\" supplied\n");
-		return -EINVAL;
-	}
+	else
+		ret = pwm_regulator_init_continuous(pdev, drvdata);
+	if (ret)
+		return ret;
 
 	config.init_data = of_get_regulator_init_data(&pdev->dev, np,
 						      &pwm_regulator_desc);
-- 
2.1.4