[PATCH 9/9] gpio: shared: generalize most code to firmware nodes

[Bartosz Golaszewski]

Ahead of adding support for sharing of GPIOs for other types of firmware
nodes, convert as much code in gpiolib-shared.c as possible to using
fwnode APIs and guard the remaining OF-specific bits with CONFIG_OF
guards.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxxxxxxxx>
---
 drivers/gpio/gpiolib-shared.c | 241 +++++++++++++++++++++++-------------------
 1 file changed, 131 insertions(+), 110 deletions(-)

diff --git a/drivers/gpio/gpiolib-shared.c b/drivers/gpio/gpiolib-shared.c
index 8c9ac9d9330490b17fb3936b8758beb97a308a15..58ac049bb603e2946c81e67a047b4788d39213b4 100644
--- a/drivers/gpio/gpiolib-shared.c
+++ b/drivers/gpio/gpiolib-shared.c
@@ -23,6 +23,7 @@
 #include <linux/property.h>
 #include <linux/slab.h>
 #include <linux/string.h>
+#include <linux/string_helpers.h>
 
 #include "gpiolib.h"
 #include "gpiolib-shared.h"
@@ -63,7 +64,7 @@ struct gpio_shared_entry {
 static LIST_HEAD(gpio_shared_list);
 static DEFINE_IDA(gpio_shared_ida);
 
-#if IS_ENABLED(CONFIG_OF)
+
 static struct gpio_shared_entry *
 gpio_shared_find_entry(struct fwnode_handle *controller_node,
 		       unsigned int offset)
@@ -133,158 +134,162 @@ static int gpio_shared_setup_reset_proxy(struct gpio_shared_entry *entry,
 }
 
 /* Handle all special nodes that we should ignore. */
-static bool gpio_shared_of_node_ignore(struct device_node *node)
+static bool gpio_shared_fwnode_ignore(struct fwnode_handle *fwnode)
 {
 	/* Ignore disabled devices. */
-	if (!of_device_is_available(node))
+	if (!fwnode_device_is_available(fwnode))
 		return true;
 
 	/*
-	 * __symbols__ is a special, internal node and should not be considered
-	 * when scanning for shared GPIOs.
+	 * On OF-systems __symbols__ is a special, internal node and should not
+	 * be considered when scanning for shared GPIOs.
 	 */
-	if (of_node_name_eq(node, "__symbols__"))
+	if (fwnode_name_eq(fwnode, "__symbols__"))
 		return true;
 
 	/*
 	 * GPIO hogs have a "gpios" property which is not a phandle and can't
 	 * possibly refer to a shared GPIO.
 	 */
-	if (of_property_present(node, "gpio-hog"))
+	if (fwnode_property_present(fwnode, "gpio-hog"))
 		return true;
 
 	return false;
 }
 
-static int gpio_shared_of_traverse(struct device_node *curr)
+static int gpio_shared_fwnode_scan_property(struct fwnode_handle *curr,
+					    const char *propname)
 {
+	struct fwnode_reference_args args;
 	struct gpio_shared_entry *entry;
 	size_t con_id_len, suffix_len;
 	struct fwnode_handle *fwnode;
-	struct of_phandle_args args;
 	struct gpio_shared_ref *ref;
-	struct property *prop;
 	unsigned int offset;
 	const char *suffix;
-	int ret, count, i;
+	int ret, i, count;
 
-	if (gpio_shared_of_node_ignore(curr))
+	/*
+	 * The standard name for a GPIO property is "foo-gpios"
+	 * or "foo-gpio". Some bindings also use "gpios" or "gpio".
+	 * There are some legacy device-trees which have a different
+	 * naming convention and for which we have rename quirks in
+	 * place in gpiolib-of.c. I don't think any of them require
+	 * support for shared GPIOs so for now let's just ignore
+	 * them. We can always just export the quirk list and
+	 * iterate over it here.
+	 */
+	if (!strends(propname, "-gpios") && !strends(propname, "-gpio") &&
+	    strcmp(propname, "gpios") != 0 && strcmp(propname, "gpio") != 0)
 		return 0;
 
-	for_each_property_of_node(curr, prop) {
-		/*
-		 * The standard name for a GPIO property is "foo-gpios"
-		 * or "foo-gpio". Some bindings also use "gpios" or "gpio".
-		 * There are some legacy device-trees which have a different
-		 * naming convention and for which we have rename quirks in
-		 * place in gpiolib-of.c. I don't think any of them require
-		 * support for shared GPIOs so for now let's just ignore
-		 * them. We can always just export the quirk list and
-		 * iterate over it here.
-		 */
-		if (!strends(prop->name, "-gpios") &&
-		    !strends(prop->name, "-gpio") &&
-		    strcmp(prop->name, "gpios") != 0 &&
-		    strcmp(prop->name, "gpio") != 0)
-			continue;
-
-		count = of_count_phandle_with_args(curr, prop->name,
-						   "#gpio-cells");
-		if (count <= 0)
-			continue;
+	count = fwnode_property_count_references(curr, propname, "#gpio-cells");
+	if (count <= 0)
+		return 0;
 
-		for (i = 0; i < count; i++) {
-			struct device_node *np __free(device_node) = NULL;
-			char *con_id __free(kfree) = NULL;
+	for (i = 0; i < count; i++) {
+		struct fwnode_handle *ctrl __free(fwnode_handle) = NULL;
+		char *con_id __free(kfree) = NULL;
 
-			ret = of_parse_phandle_with_args(curr, prop->name,
-							 "#gpio-cells", i,
+		ret = fwnode_property_get_reference_args(curr, propname,
+							 "#gpio-cells", 0, i,
 							 &args);
-			if (ret)
-				continue;
+		if (ret)
+			continue;
 
-			np = args.np;
+		ctrl = args.fwnode;
 
-			if (!of_property_present(np, "gpio-controller"))
-				continue;
+		if (!fwnode_property_present(ctrl, "gpio-controller"))
+			continue;
 
-			/*
-			 * We support 1, 2 and 3 cell GPIO bindings in the
-			 * kernel currently. There's only one old MIPS dts that
-			 * has a one-cell binding but there's no associated
-			 * consumer so it may as well be an error. There don't
-			 * seem to be any 3-cell users of non-exclusive GPIOs,
-			 * so we can skip this as well. Let's occupy ourselves
-			 * with the predominant 2-cell binding with the first
-			 * cell indicating the hardware offset of the GPIO and
-			 * the second defining the GPIO flags of the request.
-			 */
-			if (args.args_count != 2)
-				continue;
+		/*
+		 * We support 1, 2 and 3 cell GPIO bindings in the
+		 * kernel currently. There's only one old MIPS dts that
+		 * has a one-cell binding but there's no associated
+		 * consumer so it may as well be an error. There don't
+		 * seem to be any 3-cell users of non-exclusive GPIOs,
+		 * so we can skip this as well. Let's occupy ourselves
+		 * with the predominant 2-cell binding with the first
+		 * cell indicating the hardware offset of the GPIO and
+		 * the second defining the GPIO flags of the request.
+		 */
+		if (args.nargs != 2)
+			continue;
 
-			fwnode = of_fwnode_handle(args.np);
-			offset = args.args[0];
+		fwnode = ctrl;
+		offset = args.args[0];
 
-			entry = gpio_shared_find_entry(fwnode, offset);
-			if (!entry) {
-				entry = kzalloc_obj(*entry);
-				if (!entry)
-					return -ENOMEM;
+		entry = gpio_shared_find_entry(fwnode, offset);
+		if (!entry) {
+			entry = kzalloc_obj(*entry);
+			if (!entry)
+				return -ENOMEM;
 
-				entry->fwnode = fwnode_handle_get(fwnode);
-				entry->offset = offset;
-				entry->index = count;
-				INIT_LIST_HEAD(&entry->refs);
-				mutex_init(&entry->lock);
+			entry->fwnode = fwnode_handle_get(fwnode);
+			entry->offset = offset;
+			entry->index = count;
+			INIT_LIST_HEAD(&entry->refs);
+			mutex_init(&entry->lock);
 
-				list_add_tail(&entry->list, &gpio_shared_list);
-			}
+			list_add_tail(&entry->list, &gpio_shared_list);
+		}
 
-			if (strends(prop->name, "gpios"))
-				suffix = "-gpios";
-			else if (strends(prop->name, "gpio"))
-				suffix = "-gpio";
-			else
-				suffix = NULL;
-			if (!suffix)
-				continue;
+		if (strends(propname, "gpios"))
+			suffix = "-gpios";
+		else if (strends(propname, "gpio"))
+			suffix = "-gpio";
+		else
+			suffix = NULL;
+		if (!suffix)
+			continue;
 
-			/* We only set con_id if there's actually one. */
-			if (strcmp(prop->name, "gpios") && strcmp(prop->name, "gpio")) {
-				con_id = kstrdup(prop->name, GFP_KERNEL);
-				if (!con_id)
-					return -ENOMEM;
+		/* We only set con_id if there's actually one. */
+		if (strcmp(propname, "gpios") && strcmp(propname, "gpio")) {
+			con_id = kstrdup(propname, GFP_KERNEL);
+			if (!con_id)
+				return -ENOMEM;
 
-				con_id_len = strlen(con_id);
-				suffix_len = strlen(suffix);
+			con_id_len = strlen(con_id);
+			suffix_len = strlen(suffix);
 
-				con_id[con_id_len - suffix_len] = '\0';
-			}
+			con_id[con_id_len - suffix_len] = '\0';
+		}
 
-			struct fwnode_handle *curr_fwnode =
-				fwnode_handle_get(of_fwnode_handle(curr));
-			ref = gpio_shared_make_ref(curr_fwnode, con_id, args.args[1]);
-			if (!ref) {
-				fwnode_handle_put(curr_fwnode);
-				return -ENOMEM;
-			}
+		ref = gpio_shared_make_ref(fwnode_handle_get(curr), con_id, args.args[1]);
+		if (!ref) {
+			fwnode_handle_put(curr);
+			return -ENOMEM;
+		}
 
-			if (!list_empty(&entry->refs))
-				pr_debug("GPIO %u at %s is shared by multiple firmware nodes\n",
-					 entry->offset, fwnode_get_name(entry->fwnode));
+		if (!list_empty(&entry->refs))
+			pr_debug("GPIO %u at %s is shared by multiple firmware nodes\n",
+				 entry->offset, fwnode_get_name(entry->fwnode));
 
-			list_add_tail(&ref->list, &entry->refs);
+		list_add_tail(&ref->list, &entry->refs);
 
-			if (strcmp(prop->name, "reset-gpios") == 0) {
-				ret = gpio_shared_setup_reset_proxy(entry, args.args[1]);
-				if (ret)
-					return ret;
-			}
+		if (strcmp(propname, "reset-gpios") == 0) {
+			ret = gpio_shared_setup_reset_proxy(entry, args.args[1]);
+			if (ret)
+				return ret;
 		}
 	}
 
-	for_each_child_of_node_scoped(curr, child) {
-		ret = gpio_shared_of_traverse(child);
+	return 0;
+}
+
+static int gpio_shared_fwnode_scan_properties(struct fwnode_handle *curr)
+{
+	char **props;
+	int ret, i;
+
+	ret = fwnode_property_get_names(curr, &props);
+	if (ret <= 0)
+		return ret;
+
+	CLASS(strarray, names)(props, ret);
+
+	for (i = 0; i < names.size; i++) {
+		ret = gpio_shared_fwnode_scan_property(curr, names.array[i]);
 		if (ret)
 			return ret;
 	}
@@ -292,19 +297,35 @@ static int gpio_shared_of_traverse(struct device_node *curr)
 	return 0;
 }
 
-static int gpio_shared_of_scan(void)
+static int gpio_shared_fwnode_traverse(struct fwnode_handle *curr)
 {
-	if (of_root)
-		return gpio_shared_of_traverse(of_root);
+	int ret;
+
+	if (gpio_shared_fwnode_ignore(curr))
+		return 0;
+
+	ret = gpio_shared_fwnode_scan_properties(curr);
+	if (ret)
+		return ret;
+
+	fwnode_for_each_child_node_scoped(curr, child) {
+		ret = gpio_shared_fwnode_traverse(child);
+		if (ret)
+			return ret;
+	}
 
 	return 0;
 }
-#else
+
 static int gpio_shared_of_scan(void)
 {
+#if IS_ENABLED(CONFIG_OF)
+	if (of_root)
+		return gpio_shared_fwnode_traverse(of_fwnode_handle(of_root));
+#endif
+
 	return 0;
 }
-#endif /* CONFIG_OF */
 
 static void gpio_shared_adev_release(struct device *dev)
 {

-- 
2.47.3