regulator: Add GPIO enable control to fixed voltage regulator driver
Now fixed regulators that have their enable pin connected to a GPIO line
can use the fixed regulator driver for regulator enable/disable control.
The GPIO number and polarity information is passed through platform data.
GPIO enable control is achieved using gpiolib.
Signed-off-by: Roger Quadros <ext-roger.quadros@nokia.com>
Reviewed-by: Philipp Zabel <philipp.zabel@gmail.com>
Reviewed-by: Felipe Balbi <felipe.balbi@nokia.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
diff --git a/drivers/regulator/fixed.c b/drivers/regulator/fixed.c
index 9c7f956..f8b2957 100644
--- a/drivers/regulator/fixed.c
+++ b/drivers/regulator/fixed.c
@@ -5,6 +5,9 @@
*
* Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
*
+ * Copyright (c) 2009 Nokia Corporation
+ * Roger Quadros <ext-roger.quadros@nokia.com>
+ *
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
@@ -20,20 +23,45 @@
#include <linux/platform_device.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/fixed.h>
+#include <linux/gpio.h>
struct fixed_voltage_data {
struct regulator_desc desc;
struct regulator_dev *dev;
int microvolts;
+ int gpio;
+ unsigned enable_high:1;
+ unsigned is_enabled:1;
};
static int fixed_voltage_is_enabled(struct regulator_dev *dev)
{
- return 1;
+ struct fixed_voltage_data *data = rdev_get_drvdata(dev);
+
+ return data->is_enabled;
}
static int fixed_voltage_enable(struct regulator_dev *dev)
{
+ struct fixed_voltage_data *data = rdev_get_drvdata(dev);
+
+ if (gpio_is_valid(data->gpio)) {
+ gpio_set_value_cansleep(data->gpio, data->enable_high);
+ data->is_enabled = 1;
+ }
+
+ return 0;
+}
+
+static int fixed_voltage_disable(struct regulator_dev *dev)
+{
+ struct fixed_voltage_data *data = rdev_get_drvdata(dev);
+
+ if (gpio_is_valid(data->gpio)) {
+ gpio_set_value_cansleep(data->gpio, !data->enable_high);
+ data->is_enabled = 0;
+ }
+
return 0;
}
@@ -58,6 +86,7 @@
static struct regulator_ops fixed_voltage_ops = {
.is_enabled = fixed_voltage_is_enabled,
.enable = fixed_voltage_enable,
+ .disable = fixed_voltage_disable,
.get_voltage = fixed_voltage_get_voltage,
.list_voltage = fixed_voltage_list_voltage,
};
@@ -87,13 +116,62 @@
drvdata->desc.n_voltages = 1;
drvdata->microvolts = config->microvolts;
+ drvdata->gpio = config->gpio;
+
+ if (gpio_is_valid(config->gpio)) {
+ drvdata->enable_high = config->enable_high;
+
+ /* FIXME: Remove below print warning
+ *
+ * config->gpio must be set to -EINVAL by platform code if
+ * GPIO control is not required. However, early adopters
+ * not requiring GPIO control may forget to initialize
+ * config->gpio to -EINVAL. This will cause GPIO 0 to be used
+ * for GPIO control.
+ *
+ * This warning will be removed once there are a couple of users
+ * for this driver.
+ */
+ if (!config->gpio)
+ dev_warn(&pdev->dev,
+ "using GPIO 0 for regulator enable control\n");
+
+ ret = gpio_request(config->gpio, config->supply_name);
+ if (ret) {
+ dev_err(&pdev->dev,
+ "Could not obtain regulator enable GPIO %d: %d\n",
+ config->gpio, ret);
+ goto err_name;
+ }
+
+ /* set output direction without changing state
+ * to prevent glitch
+ */
+ drvdata->is_enabled = config->enabled_at_boot;
+ ret = drvdata->is_enabled ?
+ config->enable_high : !config->enable_high;
+
+ ret = gpio_direction_output(config->gpio, ret);
+ if (ret) {
+ dev_err(&pdev->dev,
+ "Could not configure regulator enable GPIO %d direction: %d\n",
+ config->gpio, ret);
+ goto err_gpio;
+ }
+
+ } else {
+ /* Regulator without GPIO control is considered
+ * always enabled
+ */
+ drvdata->is_enabled = 1;
+ }
drvdata->dev = regulator_register(&drvdata->desc, &pdev->dev,
config->init_data, drvdata);
if (IS_ERR(drvdata->dev)) {
ret = PTR_ERR(drvdata->dev);
dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
- goto err_name;
+ goto err_gpio;
}
platform_set_drvdata(pdev, drvdata);
@@ -103,6 +181,9 @@
return 0;
+err_gpio:
+ if (gpio_is_valid(config->gpio))
+ gpio_free(config->gpio);
err_name:
kfree(drvdata->desc.name);
err:
@@ -118,6 +199,9 @@
kfree(drvdata->desc.name);
kfree(drvdata);
+ if (gpio_is_valid(drvdata->gpio))
+ gpio_free(drvdata->gpio);
+
return 0;
}
