diff mbox

[1/3] regulator: add support for user space controlled regulators

Message ID 1481903550-3582-2-git-send-email-bgolaszewski@baylibre.com
State New
Headers show

Commit Message

Bartosz Golaszewski Dec. 16, 2016, 3:52 p.m. UTC 
Add a new flag to struct regulator_desc indicating whether a regulator
can be controlled from user space and implement a routine in regulator
core allowing to toggle the regulator state via the sysfs 'state'
attribute.

This is useful for gpio power switches.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>

---
 drivers/regulator/core.c         | 38 +++++++++++++++++++++++++++++++++++++-
 include/linux/regulator/driver.h |  5 +++++
 2 files changed, 42 insertions(+), 1 deletion(-)

-- 
2.9.3

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Comments

Mark Brown Dec. 16, 2016, 6:10 p.m. UTC | #1 
On Fri, Dec 16, 2016 at 04:52:28PM +0100, Bartosz Golaszewski wrote:

> Add a new flag to struct regulator_desc indicating whether a regulator

> can be controlled from user space and implement a routine in regulator

> core allowing to toggle the regulator state via the sysfs 'state'

> attribute.


No, we've been through this repeatedly before - search the archives.
Write a driver for your hardware which exposes a control for bouncing
the power if that's something that makes sense in your application.
Doing this at the regulator level is just far too likely to result in
poorly integrated systems.
diff mbox

Patch

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 5c1519b..f77de8f 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -99,6 +99,7 @@  struct regulator_supply_alias {
 };
 
 static int _regulator_is_enabled(struct regulator_dev *rdev);
+static int _regulator_enable(struct regulator_dev *rdev);
 static int _regulator_disable(struct regulator_dev *rdev);
 static int _regulator_get_voltage(struct regulator_dev *rdev);
 static int _regulator_get_current_limit(struct regulator_dev *rdev);
@@ -401,7 +402,42 @@  static ssize_t regulator_state_show(struct device *dev,
 
 	return ret;
 }
-static DEVICE_ATTR(state, 0444, regulator_state_show, NULL);
+static ssize_t regulator_state_set(struct device *dev,
+				   struct device_attribute *attr,
+				   const char *buf, size_t len)
+{
+	struct regulator_dev *rdev = dev_get_drvdata(dev);
+	bool enable;
+	ssize_t ret;
+
+	if (!rdev->desc->userspace_control)
+		return -EPERM;
+
+	if (sysfs_streq(buf, "enabled\n") || sysfs_streq(buf, "1"))
+		enable = true;
+	else if (sysfs_streq(buf, "disabled\n") || sysfs_streq(buf, "0"))
+		enable = false;
+	else
+		return -EINVAL;
+
+	mutex_lock(&rdev->mutex);
+
+	if ((enable && _regulator_is_enabled(rdev)) ||
+	    (!enable && !_regulator_is_enabled(rdev))) {
+		mutex_unlock(&rdev->mutex);
+		return -EBUSY;
+	}
+
+	ret = enable ? _regulator_enable(rdev) : _regulator_disable(rdev);
+
+	mutex_unlock(&rdev->mutex);
+
+	if (ret)
+		return ret;
+
+	return len;
+}
+static DEVICE_ATTR(state, 0644, regulator_state_show, regulator_state_set);
 
 static ssize_t regulator_status_show(struct device *dev,
 				   struct device_attribute *attr, char *buf)
diff --git a/include/linux/regulator/driver.h b/include/linux/regulator/driver.h
index 37b5324..0e7ad95 100644
--- a/include/linux/regulator/driver.h
+++ b/include/linux/regulator/driver.h
@@ -293,6 +293,9 @@  enum regulator_type {
  * @off_on_delay: guard time (in uS), before re-enabling a regulator
  *
  * @of_map_mode: Maps a hardware mode defined in a DeviceTree to a standard mode
+ *
+ * @userspace_control: A flag to indicate whether this regulator can be
+ *                     controlled from user-space.
  */
 struct regulator_desc {
 	const char *name;
@@ -347,6 +350,8 @@  struct regulator_desc {
 	unsigned int off_on_delay;
 
 	unsigned int (*of_map_mode)(unsigned int mode);
+
+	unsigned int userspace_control;
 };
 
 /**