gpiolib: consolidate GPIO lookups

Ensure that all paths to obtain/look up GPIOD from generic
consumer-visible APIs go through the new gpiod_find_and_request()
helper, so that we can easily extend it with support for new firmware
mechanisms.

The only exception is OF-specific [devm_]gpiod_get_from_of_node() API
that is still being used by a couple of drivers and will be removed as
soon as patches converting them to use generic fwnode/device APIs are
accepted.
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

drivers/gpio/gpiolib-acpi.c

@@ -1024,45 +1024,6 @@ struct gpio_desc *acpi_find_gpio(struct fwnode_handle *fwnode,
 	return desc;
 }
 
-/**
- * acpi_node_get_gpiod() - get a GPIO descriptor from ACPI resources
- * @fwnode: pointer to an ACPI firmware node to get the GPIO information from
- * @propname: Property name of the GPIO
- * @index: index of GpioIo/GpioInt resource (starting from %0)
- * @lflags: bitmask of gpio_lookup_flags GPIO_* values
- * @dflags: gpiod initialization flags
- *
- * If @fwnode is an ACPI device object, call acpi_get_gpiod_by_index() for it.
- * Otherwise (i.e. it is a data-only non-device object), use the property-based
- * GPIO lookup to get to the GPIO resource with the relevant information and use
- * that to obtain the GPIO descriptor to return.
- *
- * If the GPIO cannot be translated or there is an error an ERR_PTR is
- * returned.
- */
-struct gpio_desc *acpi_node_get_gpiod(struct fwnode_handle *fwnode,
-				      const char *propname, int index,
-				      unsigned long *lflags,
-				      enum gpiod_flags *dflags)
-{
-	struct acpi_gpio_info info;
-	struct acpi_device *adev;
-	struct gpio_desc *desc;
-
-	adev = to_acpi_device_node(fwnode);
-	if (adev)
-		desc = acpi_get_gpiod_by_index(adev, propname, index, &info);
-	else
-		desc = acpi_get_gpiod_from_data(fwnode, propname, index, &info);
-
-	if (!IS_ERR(desc)) {
-		acpi_gpio_update_gpiod_flags(dflags, &info);
-		acpi_gpio_update_gpiod_lookup_flags(lflags, &info);
-	}
-
-	return desc;
-}
-
 /**
  * acpi_dev_gpio_irq_wake_get_by() - Find GpioInt and translate it to Linux IRQ number
  * @adev: pointer to a ACPI device to get IRQ from

drivers/gpio/gpiolib-acpi.h

@@ -24,10 +24,6 @@ struct gpio_desc *acpi_find_gpio(struct fwnode_handle *fwnode,
 				 unsigned int idx,
 				 enum gpiod_flags *dflags,
 				 unsigned long *lookupflags);
-struct gpio_desc *acpi_node_get_gpiod(struct fwnode_handle *fwnode,
-				      const char *propname, int index,
-				      unsigned long *lflags,
-				      enum gpiod_flags *dflags);
 
 int acpi_gpio_count(struct device *dev, const char *con_id);
 #else
@@ -49,12 +45,6 @@ acpi_find_gpio(struct fwnode_handle *fwnode, const char *con_id,
 {
 	return ERR_PTR(-ENOENT);
 }
-static inline struct gpio_desc *
-acpi_node_get_gpiod(struct fwnode_handle *fwnode, const char *propname,
-		    int index, unsigned long *lflags, enum gpiod_flags *dflags)
-{
-	return ERR_PTR(-ENXIO);
-}
 static inline int acpi_gpio_count(struct device *dev, const char *con_id)
 {
 	return -ENODEV;

drivers/gpio/gpiolib.c

@@ -366,7 +366,7 @@ static int gpiochip_set_desc_names(struct gpio_chip *gc)
 static int devprop_gpiochip_set_names(struct gpio_chip *chip)
 {
 	struct gpio_device *gdev = chip->gpiodev;
-	struct fwnode_handle *fwnode = dev_fwnode(&gdev->dev);
+	const struct fwnode_handle *fwnode = dev_fwnode(&gdev->dev);
 	const char **names;
 	int ret, i;
 	int count;
@@ -3853,58 +3853,84 @@ static int platform_gpio_count(struct device *dev, const char *con_id)
 	return count;
 }
 
-/**
- * fwnode_get_named_gpiod - obtain a GPIO from firmware node
- * @fwnode:	handle of the firmware node
- * @propname:	name of the firmware property representing the GPIO
- * @index:	index of the GPIO to obtain for the consumer
- * @dflags:	GPIO initialization flags
- * @label:	label to attach to the requested GPIO
- *
- * This function can be used for drivers that get their configuration
- * from opaque firmware.
- *
- * The function properly finds the corresponding GPIO using whatever is the
- * underlying firmware interface and then makes sure that the GPIO
- * descriptor is requested before it is returned to the caller.
- *
- * Returns:
- * On successful request the GPIO pin is configured in accordance with
- * provided @dflags.
- *
- * In case of error an ERR_PTR() is returned.
- */
-static struct gpio_desc *fwnode_get_named_gpiod(struct fwnode_handle *fwnode,
-						const char *propname, int index,
-						enum gpiod_flags dflags,
-						const char *label)
+static struct gpio_desc *gpiod_find_by_fwnode(struct fwnode_handle *fwnode,
+					      struct device *consumer,
+					      const char *con_id,
+					      unsigned int idx,
+					      enum gpiod_flags *flags,
+					      unsigned long *lookupflags)
 {
-	unsigned long lflags = GPIO_LOOKUP_FLAGS_DEFAULT;
-	struct gpio_desc *desc = ERR_PTR(-ENODEV);
-	int ret;
+	struct gpio_desc *desc = ERR_PTR(-ENOENT);
 
 	if (is_of_node(fwnode)) {
-		desc = gpiod_get_from_of_node(to_of_node(fwnode),
-					      propname, index,
-					      dflags,
-					      label);
-		return desc;
+		dev_dbg(consumer, "using DT '%pfw' for '%s' GPIO lookup\n",
+			fwnode, con_id);
+		desc = of_find_gpio(to_of_node(fwnode), con_id, idx, lookupflags);
 	} else if (is_acpi_node(fwnode)) {
-		desc = acpi_node_get_gpiod(fwnode, propname, index,
-					   &lflags, &dflags);
-		if (IS_ERR(desc))
+		dev_dbg(consumer, "using ACPI '%pfw' for '%s' GPIO lookup\n",
+			fwnode, con_id);
+		desc = acpi_find_gpio(fwnode, con_id, idx, flags, lookupflags);
+	}
+
+	return desc;
+}
+
+static struct gpio_desc *gpiod_find_and_request(struct device *consumer,
+						struct fwnode_handle *fwnode,
+						const char *con_id,
+						unsigned int idx,
+						enum gpiod_flags flags,
+						const char *label,
+						bool platform_lookup_allowed)
+{
+	struct gpio_desc *desc = ERR_PTR(-ENOENT);
+	unsigned long lookupflags;
+	int ret;
+
+	if (!IS_ERR_OR_NULL(fwnode))
+		desc = gpiod_find_by_fwnode(fwnode, consumer, con_id, idx,
+					    &flags, &lookupflags);
+
+	if (gpiod_not_found(desc) && platform_lookup_allowed) {
+		/*
+		 * Either we are not using DT or ACPI, or their lookup did not
+		 * return a result. In that case, use platform lookup as a
+		 * fallback.
+		 */
+		dev_dbg(consumer, "using lookup tables for GPIO lookup\n");
+		desc = gpiod_find(consumer, con_id, idx, &lookupflags);
+	}
+
+	if (IS_ERR(desc)) {
+		dev_dbg(consumer, "No GPIO consumer %s found\n", con_id);
 		return desc;
-	} else {
-		return ERR_PTR(-EINVAL);
 	}
 
-	/* Currently only ACPI takes this path */
+	/*
+	 * If a connection label was passed use that, else attempt to use
+	 * the device name as label
+	 */
 	ret = gpiod_request(desc, label);
-	if (ret)
+	if (ret) {
+		if (!(ret == -EBUSY && flags & GPIOD_FLAGS_BIT_NONEXCLUSIVE))
 			return ERR_PTR(ret);
 
-	ret = gpiod_configure_flags(desc, propname, lflags, dflags);
+		/*
+		 * This happens when there are several consumers for
+		 * the same GPIO line: we just return here without
+		 * further initialization. It is a bit of a hack.
+		 * This is necessary to support fixed regulators.
+		 *
+		 * FIXME: Make this more sane and safe.
+		 */
+		dev_info(consumer,
+			 "nonexclusive access to GPIO for %s\n", con_id);
+		return desc;
+	}
+
+	ret = gpiod_configure_flags(desc, con_id, lookupflags, flags);
 	if (ret < 0) {
+		dev_dbg(consumer, "setup of GPIO %s failed\n", con_id);
 		gpiod_put(desc);
 		return ERR_PTR(ret);
 	}
@@ -3937,29 +3963,12 @@ static struct gpio_desc *fwnode_get_named_gpiod(struct fwnode_handle *fwnode,
  * In case of error an ERR_PTR() is returned.
  */
 struct gpio_desc *fwnode_gpiod_get_index(struct fwnode_handle *fwnode,
-					 const char *con_id, int index,
+					 const char *con_id,
+					 int index,
 					 enum gpiod_flags flags,
 					 const char *label)
 {
-	struct gpio_desc *desc;
-	char prop_name[32]; /* 32 is max size of property name */
-	unsigned int i;
-
-	for (i = 0; i < ARRAY_SIZE(gpio_suffixes); i++) {
-		if (con_id)
-			snprintf(prop_name, sizeof(prop_name), "%s-%s",
-					    con_id, gpio_suffixes[i]);
-		else
-			snprintf(prop_name, sizeof(prop_name), "%s",
-					    gpio_suffixes[i]);
-
-		desc = fwnode_get_named_gpiod(fwnode, prop_name, index, flags,
-					      label);
-		if (!gpiod_not_found(desc))
-			break;
-	}
-
-	return desc;
+	return gpiod_find_and_request(NULL, fwnode, con_id, index, flags, label, false);
 }
 EXPORT_SYMBOL_GPL(fwnode_gpiod_get_index);
 
@@ -4113,72 +4122,11 @@ struct gpio_desc *__must_check gpiod_get_index(struct device *dev,
 					       unsigned int idx,
 					       enum gpiod_flags flags)
 {
-	unsigned long lookupflags = GPIO_LOOKUP_FLAGS_DEFAULT;
-	struct gpio_desc *desc = NULL;
-	int ret;
-	/* Maybe we have a device name, maybe not */
-	const char *devname = dev ? dev_name(dev) : "?";
 	struct fwnode_handle *fwnode = dev ? dev_fwnode(dev) : NULL;
+	const char *devname = dev ? dev_name(dev) : "?";
+	const char *label = con_id ?: devname;
 
-	dev_dbg(dev, "GPIO lookup for consumer %s\n", con_id);
-
-	/* Using device tree? */
-	if (is_of_node(fwnode)) {
-		dev_dbg(dev, "using device tree for GPIO lookup\n");
-		desc = of_find_gpio(to_of_node(fwnode),
-				    con_id, idx, &lookupflags);
-	} else if (is_acpi_node(fwnode)) {
-		dev_dbg(dev, "using ACPI for GPIO lookup\n");
-		desc = acpi_find_gpio(fwnode,
-				      con_id, idx, &flags, &lookupflags);
-	}
-
-	/*
-	 * Either we are not using DT or ACPI, or their lookup did not return
-	 * a result. In that case, use platform lookup as a fallback.
-	 */
-	if (!desc || gpiod_not_found(desc)) {
-		dev_dbg(dev, "using lookup tables for GPIO lookup\n");
-		desc = gpiod_find(dev, con_id, idx, &lookupflags);
-	}
-
-	if (IS_ERR(desc)) {
-		dev_dbg(dev, "No GPIO consumer %s found\n", con_id);
-		return desc;
-	}
-
-	/*
-	 * If a connection label was passed use that, else attempt to use
-	 * the device name as label
-	 */
-	ret = gpiod_request(desc, con_id ?: devname);
-	if (ret) {
-		if (!(ret == -EBUSY && flags & GPIOD_FLAGS_BIT_NONEXCLUSIVE))
-			return ERR_PTR(ret);
-
-		/*
-		 * This happens when there are several consumers for
-		 * the same GPIO line: we just return here without
-		 * further initialization. It is a bit of a hack.
-		 * This is necessary to support fixed regulators.
-		 *
-		 * FIXME: Make this more sane and safe.
-		 */
-		dev_info(dev, "nonexclusive access to GPIO for %s\n", con_id ?: devname);
-		return desc;
-	}
-
-	ret = gpiod_configure_flags(desc, con_id, lookupflags, flags);
-	if (ret < 0) {
-		dev_dbg(dev, "setup of GPIO %s failed\n", con_id);
-		gpiod_put(desc);
-		return ERR_PTR(ret);
-	}
-
-	blocking_notifier_call_chain(&desc->gdev->notifier,
-				     GPIOLINE_CHANGED_REQUESTED, desc);
-
-	return desc;
+	return gpiod_find_and_request(dev, fwnode, con_id, idx, flags, label, true);
 }
 EXPORT_SYMBOL_GPL(gpiod_get_index);