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Subject[PATCH v3] regulator: Add GPIO enable control to fixed voltage regulator driver
Date
From: Roger Quadros <ext-roger.quadros@nokia.com>

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>
---
drivers/regulator/fixed.c | 75 +++++++++++++++++++++++++++++++++++++-
include/linux/regulator/fixed.h | 21 +++++++++++
2 files changed, 94 insertions(+), 2 deletions(-)

diff --git a/drivers/regulator/fixed.c b/drivers/regulator/fixed.c
index cdc674f..0888cb7 100644
--- a/drivers/regulator/fixed.c
+++ b/drivers/regulator/fixed.c
@@ -20,20 +20,45 @@
#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 +83,7 @@ static int fixed_voltage_list_voltage(struct regulator_dev *dev,
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,
};
@@ -85,12 +111,51 @@ static int regulator_fixed_voltage_probe(struct platform_device *pdev)
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 this print warning */
+ 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;
+ if (!config->enable_high)
+ drvdata->is_enabled = !drvdata->is_enabled;
+
+ ret = gpio_direction_output(config->gpio, drvdata->is_enabled);
+ 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);
- goto err_name;
+ goto err_gpio;
}

platform_set_drvdata(pdev, drvdata);
@@ -100,6 +165,9 @@ static int regulator_fixed_voltage_probe(struct platform_device *pdev)

return 0;

+err_gpio:
+ if (gpio_is_valid(config->gpio))
+ gpio_free(config->gpio);
err_name:
kfree(drvdata->desc.name);
err:
@@ -115,6 +183,9 @@ static int regulator_fixed_voltage_remove(struct platform_device *pdev)
kfree(drvdata->desc.name);
kfree(drvdata);

+ if (gpio_is_valid(drvdata->gpio))
+ gpio_free(drvdata->gpio);
+
return 0;
}

diff --git a/include/linux/regulator/fixed.h b/include/linux/regulator/fixed.h
index 91b4da3..bd75b18 100644
--- a/include/linux/regulator/fixed.h
+++ b/include/linux/regulator/fixed.h
@@ -16,9 +16,30 @@

struct regulator_init_data;

+/**
+ * struct fixed_voltage_config - fixed_voltage_config structure
+ * @supply_name: Name of the regulator supply
+ * @microvolts: Output voltage of regulator
+ * @gpio: GPIO to use for enable control
+ * set to -EINVAL if not used
+ * @enable_high: Polarity of enable GPIO
+ * 1 = Active high, 0 = Active low
+ * @enabled_at_boot: Whether regulator has been enabled at
+ * boot or not. 1 = Yes, 0 = No
+ * This is used to keep the regulator at
+ * the default state
+ * @init_data: regulator_init_data
+ *
+ * This structure contains fixed voltage regulator configuration
+ * information that must be passed by platform code to the fixed
+ * voltage regulator driver.
+ */
struct fixed_voltage_config {
const char *supply_name;
int microvolts;
+ int gpio;
+ unsigned enable_high:1;
+ unsigned enabled_at_boot:1;
struct regulator_init_data *init_data;
};

--
1.5.6.3


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