1 files changed, 197 insertions, 0 deletions

diff --git a/drivers/regulator/pwm-regulator.c b/drivers/regulator/pwm-regulator.c
new file mode 100644
index 000000000000..d3f55eaea058
--- /dev/null
+++ b/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");