regulator: pwm-regulator: get voltage and duty table from dts

rename st-pwm to pwm-regulator. And support getting voltage & duty table from
device tree, other platforms can also use this driver without any modify.

Signed-off-by: Chris Zhong <zyw@rock-chips.com>
Reviewed-by: Doug Anderson <dianders@chromium.org>
Tested-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/regulator/pwm-regulator.c

@@ -0,0 +1,197 @@
+/*
+ * Regulator driver for PWM Regulators
+ *
+ * Copyright (C) 2014 - STMicroelectronics Inc.
+ *
+ * Author: Lee Jones <lee.jones@linaro.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/err.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/machine.h>
+#include <linux/regulator/of_regulator.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/pwm.h>
+
+struct pwm_regulator_data {
+	struct regulator_desc desc;
+	struct pwm_voltages *duty_cycle_table;
+	struct pwm_device *pwm;
+	bool enabled;
+	int state;
+};
+
+struct pwm_voltages {
+	unsigned int uV;
+	unsigned int dutycycle;
+};
+
+static int pwm_regulator_get_voltage_sel(struct regulator_dev *dev)
+{
+	struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
+
+	return drvdata->state;
+}
+
+static int pwm_regulator_set_voltage_sel(struct regulator_dev *dev,
+					 unsigned selector)
+{
+	struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
+	unsigned int pwm_reg_period;
+	int dutycycle;
+	int ret;
+
+	pwm_reg_period = pwm_get_period(drvdata->pwm);
+
+	dutycycle = (pwm_reg_period *
+		    drvdata->duty_cycle_table[selector].dutycycle) / 100;
+
+	ret = pwm_config(drvdata->pwm, dutycycle, pwm_reg_period);
+	if (ret) {
+		dev_err(&dev->dev, "Failed to configure PWM\n");
+		return ret;
+	}
+
+	drvdata->state = selector;
+
+	if (!drvdata->enabled) {
+		ret = pwm_enable(drvdata->pwm);
+		if (ret) {
+			dev_err(&dev->dev, "Failed to enable PWM\n");
+			return ret;
+		}
+		drvdata->enabled = true;
+	}
+
+	return 0;
+}
+
+static int pwm_regulator_list_voltage(struct regulator_dev *dev,
+				      unsigned selector)
+{
+	struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
+
+	if (selector >= drvdata->desc.n_voltages)
+		return -EINVAL;
+
+	return drvdata->duty_cycle_table[selector].uV;
+}
+
+static struct regulator_ops pwm_regulator_voltage_ops = {
+	.set_voltage_sel = pwm_regulator_set_voltage_sel,
+	.get_voltage_sel = pwm_regulator_get_voltage_sel,
+	.list_voltage    = pwm_regulator_list_voltage,
+	.map_voltage     = regulator_map_voltage_iterate,
+};
+
+static const struct regulator_desc pwm_regulator_desc = {
+	.name		= "pwm-regulator",
+	.ops		= &pwm_regulator_voltage_ops,
+	.type		= REGULATOR_VOLTAGE,
+	.owner		= THIS_MODULE,
+	.supply_name    = "pwm",
+};
+
+static int pwm_regulator_probe(struct platform_device *pdev)
+{
+	struct pwm_regulator_data *drvdata;
+	struct property *prop;
+	struct regulator_dev *regulator;
+	struct regulator_config config = { };
+	struct device_node *np = pdev->dev.of_node;
+	int length, ret;
+
+	if (!np) {
+		dev_err(&pdev->dev, "Device Tree node missing\n");
+		return -EINVAL;
+	}
+
+	drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL);
+	if (!drvdata)
+		return -ENOMEM;
+
+	memcpy(&drvdata->desc, &pwm_regulator_desc, sizeof(pwm_regulator_desc));
+
+	/* determine the number of voltage-table */
+	prop = of_find_property(np, "voltage-table", &length);
+	if (!prop) {
+		dev_err(&pdev->dev, "No voltage-table\n");
+		return -EINVAL;
+	}
+
+	if ((length < sizeof(*drvdata->duty_cycle_table)) ||
+	    (length % sizeof(*drvdata->duty_cycle_table))) {
+		dev_err(&pdev->dev, "voltage-table length(%d) is invalid\n",
+			length);
+		return -EINVAL;
+	}
+
+	drvdata->desc.n_voltages = length / sizeof(*drvdata->duty_cycle_table);
+
+	drvdata->duty_cycle_table = devm_kzalloc(&pdev->dev,
+						 length, GFP_KERNEL);
+	if (!drvdata->duty_cycle_table)
+		return -ENOMEM;
+
+	/* read voltage table from DT property */
+	ret = of_property_read_u32_array(np, "voltage-table",
+					 (u32 *)drvdata->duty_cycle_table,
+					 length / sizeof(u32));
+	if (ret < 0) {
+		dev_err(&pdev->dev, "read voltage-table failed\n");
+		return ret;
+	}
+
+	config.init_data = of_get_regulator_init_data(&pdev->dev, np);
+	if (!config.init_data)
+		return -ENOMEM;
+
+	config.of_node = np;
+	config.dev = &pdev->dev;
+	config.driver_data = drvdata;
+
+	drvdata->pwm = devm_pwm_get(&pdev->dev, NULL);
+	if (IS_ERR(drvdata->pwm)) {
+		dev_err(&pdev->dev, "Failed to get PWM\n");
+		return PTR_ERR(drvdata->pwm);
+	}
+
+	regulator = devm_regulator_register(&pdev->dev,
+					    &drvdata->desc, &config);
+	if (IS_ERR(regulator)) {
+		dev_err(&pdev->dev, "Failed to register regulator %s\n",
+			drvdata->desc.name);
+		return PTR_ERR(regulator);
+	}
+
+	return 0;
+}
+
+static const struct of_device_id pwm_of_match[] = {
+	{ .compatible = "pwm-regulator" },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, pwm_of_match);
+
+static struct platform_driver pwm_regulator_driver = {
+	.driver = {
+		.name		= "pwm-regulator",
+		.owner		= THIS_MODULE,
+		.of_match_table = of_match_ptr(pwm_of_match),
+	},
+	.probe = pwm_regulator_probe,
+};
+
+module_platform_driver(pwm_regulator_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org>");
+MODULE_DESCRIPTION("PWM Regulator Driver");
+MODULE_ALIAS("platform:pwm-regulator");