[RFC PATCH 6/9] gpiolib: add API to get gpio desc and flags

[Mika Westerberg]

From: Aaron Lu <aaron.lu@xxxxxxxxx>

Add a new API to get the GPIO's description pointer and its flags for
both OF based system and ACPI based system. This is useful in drivers
that do not need to care about the underlying firmware interface.

Signed-off-by: Aaron Lu <aaron.lu@xxxxxxxxx>
Signed-off-by: Max Eliaser <max.eliaser@xxxxxxxxx>
Signed-off-by: Darren Hart <dvhart@xxxxxxxxxxxxxxx>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
---
 drivers/gpio/gpiolib-acpi.c   | 81 ++++++++++++++++++++++++++++++++-----------
 drivers/gpio/gpiolib.c        | 18 ++++++++++
 drivers/gpio/gpiolib.h        |  8 +++++
 include/linux/gpio/consumer.h | 11 ++++++
 4 files changed, 97 insertions(+), 21 deletions(-)

diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c
index 4a987917c186..f35e88d29a47 100644
--- a/drivers/gpio/gpiolib-acpi.c
+++ b/drivers/gpio/gpiolib-acpi.c
@@ -293,11 +293,38 @@ static int acpi_find_gpio(struct acpi_resource *ares, void *data)
 			agpio->connection_type == ACPI_RESOURCE_GPIO_TYPE_INT;
 		lookup->info.active_low =
 			agpio->polarity == ACPI_ACTIVE_LOW;
+		lookup->info.pin_config = agpio->pin_config;
 	}
 
 	return 1;
 }
 
+static struct gpio_desc *
+__acpi_get_gpiod_by_index(struct acpi_device *adev, int index,
+			  struct acpi_gpio_info *info)
+{
+	struct acpi_gpio_lookup lookup;
+	struct list_head resource_list;
+	int ret;
+
+	memset(&lookup, 0, sizeof(lookup));
+	lookup.index = index;
+
+	INIT_LIST_HEAD(&resource_list);
+	ret = acpi_dev_get_resources(adev, &resource_list, acpi_find_gpio,
+				     &lookup);
+	if (ret < 0)
+		return ERR_PTR(ret);
+
+	acpi_dev_free_resource_list(&resource_list);
+
+	if (lookup.desc && info)
+		*info = lookup.info;
+
+	return lookup.desc ? lookup.desc : ERR_PTR(-ENOENT);
+}
+
+
 /**
  * acpi_get_gpiod_by_index() - get a GPIO descriptor from device resources
  * @dev: pointer to a device to get GPIO from
@@ -318,34 +345,46 @@ static int acpi_find_gpio(struct acpi_resource *ares, void *data)
 struct gpio_desc *acpi_get_gpiod_by_index(struct device *dev, int index,
 					  struct acpi_gpio_info *info)
 {
-	struct acpi_gpio_lookup lookup;
-	struct list_head resource_list;
-	struct acpi_device *adev;
-	acpi_handle handle;
-	int ret;
-
-	if (!dev)
+	if (!dev || !ACPI_COMPANION(dev))
 		return ERR_PTR(-EINVAL);
+	return __acpi_get_gpiod_by_index(ACPI_COMPANION(dev), index, info);
+}
 
-	handle = ACPI_HANDLE(dev);
-	if (!handle || acpi_bus_get_device(handle, &adev))
-		return ERR_PTR(-ENODEV);
-
-	memset(&lookup, 0, sizeof(lookup));
-	lookup.index = index;
+struct gpio_desc *acpi_get_gpiod_flags(struct device *dev, int idx,
+				       enum gpio_lookup_flags *flags)
+{
+	struct acpi_device *adev = ACPI_COMPANION(dev);
+	struct acpi_reference_args args;
+	struct acpi_gpio_info info;
+	struct gpio_desc *desc;
+	bool active_low;
+	int ret;
 
-	INIT_LIST_HEAD(&resource_list);
-	ret = acpi_dev_get_resources(adev, &resource_list, acpi_find_gpio,
-				     &lookup);
-	if (ret < 0)
+	ret = acpi_dev_get_property_reference(adev, "gpios", NULL, idx, &args);
+	if (ret)
 		return ERR_PTR(ret);
 
-	acpi_dev_free_resource_list(&resource_list);
+	desc = __acpi_get_gpiod_by_index(args.adev, args.args[0], &info);
+	if (IS_ERR(desc))
+		return desc;
 
-	if (lookup.desc && info)
-		*info = lookup.info;
+	/*
+	 * The 3rd argument optionally specifies the pin polarity. We
+	 * use that if it exists, otherwise we resort to the pin config.
+	 * (Note that the first element of the "gpios" package goes into
+	 * arg.adev, not args.args.)
+	 */
+	if (args.nargs >= 3)
+		active_low = !!args.args[2];
+	else if (info.gpioint)
+		active_low = !!info.active_low;
+	else
+		active_low = !!(info.pin_config & ACPI_PIN_CONFIG_PULLUP);
 
-	return lookup.desc ? lookup.desc : ERR_PTR(-ENOENT);
+	if (active_low)
+		*flags |= GPIO_ACTIVE_LOW;
+
+	return desc;
 }
 
 static acpi_status
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 2ebc9071e354..e6c2413a6fbf 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -2644,6 +2644,24 @@ static struct gpio_desc *acpi_find_gpio(struct device *dev, const char *con_id,
 	return desc;
 }
 
+struct gpio_desc *dev_get_gpiod_flags(struct device *dev, unsigned int idx,
+				      enum gpio_lookup_flags *flags)
+{
+	struct gpio_desc *desc = ERR_PTR(-ENOENT);
+
+	if (!dev || !flags)
+		return ERR_PTR(-EINVAL);
+
+	/* Using device tree? */
+	if (IS_ENABLED(CONFIG_OF) && dev->of_node)
+		desc = of_find_gpio(dev, NULL, idx, flags);
+	else if (IS_ENABLED(CONFIG_ACPI) && ACPI_COMPANION(dev))
+		desc = acpi_get_gpiod_flags(dev, idx, flags);
+
+	return desc;
+}
+EXPORT_SYMBOL(dev_get_gpiod_flags);
+
 static struct gpiod_lookup_table *gpiod_find_lookup_table(struct device *dev)
 {
 	const char *dev_id = dev ? dev_name(dev) : NULL;
diff --git a/drivers/gpio/gpiolib.h b/drivers/gpio/gpiolib.h
index 1a4103dd38df..a759db968e51 100644
--- a/drivers/gpio/gpiolib.h
+++ b/drivers/gpio/gpiolib.h
@@ -25,6 +25,7 @@ enum of_gpio_flags;
 struct acpi_gpio_info {
 	bool gpioint;
 	bool active_low;
+	u8 pin_config;
 };
 
 #ifdef CONFIG_ACPI
@@ -33,6 +34,8 @@ void acpi_gpiochip_remove(struct gpio_chip *chip);
 
 struct gpio_desc *acpi_get_gpiod_by_index(struct device *dev, int index,
 					  struct acpi_gpio_info *info);
+struct gpio_desc *acpi_get_gpiod_flags(struct device *dev, int index,
+				       enum gpio_lookup_flags *flags);
 #else
 static inline void acpi_gpiochip_add(struct gpio_chip *chip) { }
 static inline void acpi_gpiochip_remove(struct gpio_chip *chip) { }
@@ -43,6 +46,11 @@ acpi_get_gpiod_by_index(struct device *dev, int index,
 {
 	return ERR_PTR(-ENOSYS);
 }
+static struct gpio_desc *acpi_get_gpiod_flags(struct device *dev, int index,
+					      enum gpio_lookup_flags *flags)
+{
+	return ERR_PTR(-ENOSYS);
+}
 #endif
 
 int gpiochip_request_own_desc(struct gpio_desc *desc, const char *label);
diff --git a/include/linux/gpio/consumer.h b/include/linux/gpio/consumer.h
index 05e53ccb708b..53f422e4f0c9 100644
--- a/include/linux/gpio/consumer.h
+++ b/include/linux/gpio/consumer.h
@@ -7,6 +7,8 @@
 
 struct device;
 
+enum gpio_lookup_flags;
+
 /**
  * Opaque descriptor for a GPIO. These are obtained using gpiod_get() and are
  * preferable to the old integer-based handles.
@@ -73,6 +75,9 @@ int gpiod_to_irq(const struct gpio_desc *desc);
 struct gpio_desc *gpio_to_desc(unsigned gpio);
 int desc_to_gpio(const struct gpio_desc *desc);
 
+struct gpio_desc *dev_get_gpiod_flags(struct device *dev, unsigned int idx,
+				      enum gpio_lookup_flags *flags);
+
 #else /* CONFIG_GPIOLIB */
 
 static inline struct gpio_desc *__must_check gpiod_get(struct device *dev,
@@ -254,6 +259,12 @@ static inline int desc_to_gpio(const struct gpio_desc *desc)
 	return -EINVAL;
 }
 
+static inline struct gpio_desc *dev_get_gpiod_flags(struct device *dev,
+			unsigned int idx, enum gpio_lookup_flags *flags)
+{
+	return ERR_PTR(-ENOSYS);
+}
+
 
 #endif /* CONFIG_GPIOLIB */
 
-- 
2.1.0.rc1

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