Merge remote-tracking branch 'regulator/topic/gpio' into v3.9-rc8

1 files changed, 123 insertions, 19 deletions

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 2434e2e1afc..6e501784158 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -51,6 +51,7 @@
 static DEFINE_MUTEX(regulator_list_mutex);
 static LIST_HEAD(regulator_list);
 static LIST_HEAD(regulator_map_list);
+static LIST_HEAD(regulator_ena_gpio_list);
 static bool has_full_constraints;
 static bool board_wants_dummy_regulator;
 
@@ -69,6 +70,19 @@ struct regulator_map {
 };
 
 /*
+ * struct regulator_enable_gpio
+ *
+ * Management for shared enable GPIO pin
+ */
+struct regulator_enable_gpio {
+	struct list_head list;
+	int gpio;
+	u32 enable_count;	/* a number of enabled shared GPIO */
+	u32 request_count;	/* a number of requested shared GPIO */
+	unsigned int ena_gpio_invert:1;
+};
+
+/*
  * struct regulator
  *
  * One for each consumer device.
@@ -1465,6 +1479,101 @@ void devm_regulator_put(struct regulator *regulator)
 }
 EXPORT_SYMBOL_GPL(devm_regulator_put);
 
+/* Manage enable GPIO list. Same GPIO pin can be shared among regulators */
+static int regulator_ena_gpio_request(struct regulator_dev *rdev,
+				const struct regulator_config *config)
+{
+	struct regulator_enable_gpio *pin;
+	int ret;
+
+	list_for_each_entry(pin, &regulator_ena_gpio_list, list) {
+		if (pin->gpio == config->ena_gpio) {
+			rdev_dbg(rdev, "GPIO %d is already used\n",
+				config->ena_gpio);
+			goto update_ena_gpio_to_rdev;
+		}
+	}
+
+	ret = gpio_request_one(config->ena_gpio,
+				GPIOF_DIR_OUT | config->ena_gpio_flags,
+				rdev_get_name(rdev));
+	if (ret)
+		return ret;
+
+	pin = kzalloc(sizeof(struct regulator_enable_gpio), GFP_KERNEL);
+	if (pin == NULL) {
+		gpio_free(config->ena_gpio);
+		return -ENOMEM;
+	}
+
+	pin->gpio = config->ena_gpio;
+	pin->ena_gpio_invert = config->ena_gpio_invert;
+	list_add(&pin->list, &regulator_ena_gpio_list);
+
+update_ena_gpio_to_rdev:
+	pin->request_count++;
+	rdev->ena_pin = pin;
+	return 0;
+}
+
+static void regulator_ena_gpio_free(struct regulator_dev *rdev)
+{
+	struct regulator_enable_gpio *pin, *n;
+
+	if (!rdev->ena_pin)
+		return;
+
+	/* Free the GPIO only in case of no use */
+	list_for_each_entry_safe(pin, n, &regulator_ena_gpio_list, list) {
+		if (pin->gpio == rdev->ena_pin->gpio) {
+			if (pin->request_count <= 1) {
+				pin->request_count = 0;
+				gpio_free(pin->gpio);
+				list_del(&pin->list);
+				kfree(pin);
+			} else {
+				pin->request_count--;
+			}
+		}
+	}
+}
+
+/**
+ * Balance enable_count of each GPIO and actual GPIO pin control.
+ * GPIO is enabled in case of initial use. (enable_count is 0)
+ * GPIO is disabled when it is not shared any more. (enable_count <= 1)
+ */
+static int regulator_ena_gpio_ctrl(struct regulator_dev *rdev, bool enable)
+{
+	struct regulator_enable_gpio *pin = rdev->ena_pin;
+
+	if (!pin)
+		return -EINVAL;
+
+	if (enable) {
+		/* Enable GPIO at initial use */
+		if (pin->enable_count == 0)
+			gpio_set_value_cansleep(pin->gpio,
+						!pin->ena_gpio_invert);
+
+		pin->enable_count++;
+	} else {
+		if (pin->enable_count > 1) {
+			pin->enable_count--;
+			return 0;
+		}
+
+		/* Disable GPIO if not used */
+		if (pin->enable_count <= 1) {
+			gpio_set_value_cansleep(pin->gpio,
+						pin->ena_gpio_invert);
+			pin->enable_count = 0;
+		}
+	}
+
+	return 0;
+}
+
 static int _regulator_do_enable(struct regulator_dev *rdev)
 {
 	int ret, delay;
@@ -1480,9 +1589,10 @@ static int _regulator_do_enable(struct regulator_dev *rdev)
 
 	trace_regulator_enable(rdev_get_name(rdev));
 
-	if (rdev->ena_gpio) {
-		gpio_set_value_cansleep(rdev->ena_gpio,
-					!rdev->ena_gpio_invert);
+	if (rdev->ena_pin) {
+		ret = regulator_ena_gpio_ctrl(rdev, true);
+		if (ret < 0)
+			return ret;
 		rdev->ena_gpio_state = 1;
 	} else if (rdev->desc->ops->enable) {
 		ret = rdev->desc->ops->enable(rdev);
@@ -1584,9 +1694,10 @@ static int _regulator_do_disable(struct regulator_dev *rdev)
 
 	trace_regulator_disable(rdev_get_name(rdev));
 
-	if (rdev->ena_gpio) {
-		gpio_set_value_cansleep(rdev->ena_gpio,
-					rdev->ena_gpio_invert);
+	if (rdev->ena_pin) {
+		ret = regulator_ena_gpio_ctrl(rdev, false);
+		if (ret < 0)
+			return ret;
 		rdev->ena_gpio_state = 0;
 
 	} else if (rdev->desc->ops->disable) {
@@ -1859,7 +1970,7 @@ EXPORT_SYMBOL_GPL(regulator_disable_regmap);
 static int _regulator_is_enabled(struct regulator_dev *rdev)
 {
 	/* A GPIO control always takes precedence */
-	if (rdev->ena_gpio)
+	if (rdev->ena_pin)
 		return rdev->ena_gpio_state;
 
 	/* If we don't know then assume that the regulator is always on */
@@ -3293,7 +3404,7 @@ static int add_regulator_attributes(struct regulator_dev *rdev)
 		if (status < 0)
 			return status;
 	}
-	if (rdev->ena_gpio || ops->is_enabled) {
+	if (rdev->ena_pin || ops->is_enabled) {
 		status = device_create_file(dev, &dev_attr_state);
 		if (status < 0)
 			return status;
@@ -3495,22 +3606,17 @@ regulator_register(const struct regulator_desc *regulator_desc,
 	dev_set_drvdata(&rdev->dev, rdev);
 
 	if (config->ena_gpio && gpio_is_valid(config->ena_gpio)) {
-		ret = gpio_request_one(config->ena_gpio,
-				       GPIOF_DIR_OUT | config->ena_gpio_flags,
-				       rdev_get_name(rdev));
+		ret = regulator_ena_gpio_request(rdev, config);
 		if (ret != 0) {
 			rdev_err(rdev, "Failed to request enable GPIO%d: %d\n",
 				 config->ena_gpio, ret);
 			goto wash;
 		}
 
-		rdev->ena_gpio = config->ena_gpio;
-		rdev->ena_gpio_invert = config->ena_gpio_invert;
-
 		if (config->ena_gpio_flags & GPIOF_OUT_INIT_HIGH)
 			rdev->ena_gpio_state = 1;
 
-		if (rdev->ena_gpio_invert)
+		if (config->ena_gpio_invert)
 			rdev->ena_gpio_state = !rdev->ena_gpio_state;
 	}
 
@@ -3590,8 +3696,7 @@ unset_supplies:
 scrub:
 	if (rdev->supply)
 		_regulator_put(rdev->supply);
-	if (rdev->ena_gpio)
-		gpio_free(rdev->ena_gpio);
+	regulator_ena_gpio_free(rdev);
 	kfree(rdev->constraints);
 wash:
 	device_unregister(&rdev->dev);
@@ -3626,8 +3731,7 @@ void regulator_unregister(struct regulator_dev *rdev)
 	unset_regulator_supplies(rdev);
 	list_del(&rdev->list);
 	kfree(rdev->constraints);
-	if (rdev->ena_gpio)
-		gpio_free(rdev->ena_gpio);
+	regulator_ena_gpio_free(rdev);
 	device_unregister(&rdev->dev);
 	mutex_unlock(&regulator_list_mutex);
 }