1 files changed, 87 insertions, 47 deletions

diff --git a/drivers/gpio/gpiolib-swnode.c b/drivers/gpio/gpiolib-swnode.c
index b5a6eaf3729b..b44f35d68459 100644
--- a/drivers/gpio/gpiolib-swnode.c
+++ b/drivers/gpio/gpiolib-swnode.c
@@ -4,8 +4,13 @@
  *
  * Copyright 2022 Google LLC
  */
+
+#define pr_fmt(fmt) "gpiolib: swnode: " fmt
+
 #include <linux/err.h>
 #include <linux/errno.h>
+#include <linux/export.h>
+#include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/printk.h>
 #include <linux/property.h>
@@ -17,36 +22,39 @@
 #include "gpiolib.h"
 #include "gpiolib-swnode.h"
 
-static void swnode_format_propname(const char *con_id, char *propname,
-				   size_t max_size)
+#define GPIOLIB_SWNODE_UNDEFINED_NAME "swnode-gpio-undefined"
+
+static struct gpio_device *swnode_get_gpio_device(struct fwnode_handle *fwnode)
 {
+	const struct software_node *gdev_node;
+	struct gpio_device *gdev;
+
+	gdev_node = to_software_node(fwnode);
+	if (!gdev_node || !gdev_node->name)
+		goto fwnode_lookup;
+
 	/*
-	 * Note we do not need to try both -gpios and -gpio suffixes,
-	 * as, unlike OF and ACPI, we can fix software nodes to conform
-	 * to the proper binding.
+	 * Check for a special node that identifies undefined GPIOs, this is
+	 * primarily used as a key for internal chip selects in SPI bindings.
 	 */
-	if (con_id)
-		snprintf(propname, max_size, "%s-gpios", con_id);
-	else
-		strscpy(propname, "gpios", max_size);
-}
+	if (IS_ENABLED(CONFIG_GPIO_SWNODE_UNDEFINED) &&
+	    !strcmp(gdev_node->name, GPIOLIB_SWNODE_UNDEFINED_NAME))
+		return ERR_PTR(-ENOENT);
 
-static int swnode_gpiochip_match_name(struct gpio_chip *chip, void *data)
-{
-	return !strcmp(chip->label, data);
+fwnode_lookup:
+	gdev = gpio_device_find_by_fwnode(fwnode);
+	return gdev ?: ERR_PTR(-EPROBE_DEFER);
 }
 
-static struct gpio_chip *swnode_get_chip(struct fwnode_handle *fwnode)
+static int swnode_gpio_get_reference(const struct fwnode_handle *fwnode,
+				     const char *propname, unsigned int idx,
+				     struct fwnode_reference_args *args)
 {
-	const struct software_node *chip_node;
-	struct gpio_chip *chip;
-
-	chip_node = to_software_node(fwnode);
-	if (!chip_node || !chip_node->name)
-		return ERR_PTR(-EINVAL);
-
-	chip = gpiochip_find((void *)chip_node->name, swnode_gpiochip_match_name);
-	return chip ?: ERR_PTR(-EPROBE_DEFER);
+	/*
+	 * We expect all swnode-described GPIOs have GPIO number and
+	 * polarity arguments, hence nargs is set to 2.
+	 */
+	return fwnode_property_get_reference_args(fwnode, propname, NULL, 2, idx, args);
 }
 
 struct gpio_desc *swnode_find_gpio(struct fwnode_handle *fwnode,
@@ -55,34 +63,36 @@ struct gpio_desc *swnode_find_gpio(struct fwnode_handle *fwnode,
 {
 	const struct software_node *swnode;
 	struct fwnode_reference_args args;
-	struct gpio_chip *chip;
 	struct gpio_desc *desc;
 	char propname[32]; /* 32 is max size of property name */
-	int error;
+	int ret = 0;
 
 	swnode = to_software_node(fwnode);
 	if (!swnode)
 		return ERR_PTR(-EINVAL);
 
-	swnode_format_propname(con_id, propname, sizeof(propname));
-
-	/*
-	 * We expect all swnode-described GPIOs have GPIO number and
-	 * polarity arguments, hence nargs is set to 2.
-	 */
-	error = fwnode_property_get_reference_args(fwnode, propname, NULL, 2, idx, &args);
-	if (error) {
+	for_each_gpio_property_name(propname, con_id) {
+		ret = swnode_gpio_get_reference(fwnode, propname, idx, &args);
+		if (ret == 0)
+			break;
+	}
+	if (ret) {
 		pr_debug("%s: can't parse '%s' property of node '%pfwP[%d]'\n",
 			__func__, propname, fwnode, idx);
-		return ERR_PTR(error);
+		return ERR_PTR(ret);
 	}
 
-	chip = swnode_get_chip(args.fwnode);
+	struct gpio_device *gdev __free(gpio_device_put) =
+					swnode_get_gpio_device(args.fwnode);
 	fwnode_handle_put(args.fwnode);
-	if (IS_ERR(chip))
-		return ERR_CAST(chip);
+	if (IS_ERR(gdev))
+		return ERR_CAST(gdev);
 
-	desc = gpiochip_get_desc(chip, args.args[0]);
+	/*
+	 * FIXME: The GPIO device reference is put at return but the descriptor
+	 * is passed on. Find a proper solution.
+	 */
+	desc = gpio_device_get_desc(gdev, args.args[0]);
 	*flags = args.args[1]; /* We expect native GPIO flags */
 
 	pr_debug("%s: parsed '%s' property of node '%pfwP[%d]' - status (%d)\n",
@@ -97,7 +107,7 @@ struct gpio_desc *swnode_find_gpio(struct fwnode_handle *fwnode,
  *		system-global GPIOs
  * @con_id:	function within the GPIO consumer
  *
- * Return:
+ * Returns:
  * The number of GPIOs associated with a device / function or %-ENOENT,
  * if no GPIO has been assigned to the requested function.
  */
@@ -107,18 +117,48 @@ int swnode_gpio_count(const struct fwnode_handle *fwnode, const char *con_id)
 	char propname[32];
 	int count;
 
-	swnode_format_propname(con_id, propname, sizeof(propname));
-
 	/*
 	 * This is not very efficient, but GPIO lists usually have only
 	 * 1 or 2 entries.
 	 */
-	count = 0;
-	while (fwnode_property_get_reference_args(fwnode, propname, NULL, 0,
-						  count, &args) == 0) {
-		fwnode_handle_put(args.fwnode);
-		count++;
+	for_each_gpio_property_name(propname, con_id) {
+		count = 0;
+		while (swnode_gpio_get_reference(fwnode, propname, count, &args) == 0) {
+			fwnode_handle_put(args.fwnode);
+			count++;
+		}
+		if (count)
+			return count;
 	}
 
-	return count ?: -ENOENT;
+	return -ENOENT;
+}
+
+#if IS_ENABLED(CONFIG_GPIO_SWNODE_UNDEFINED)
+/*
+ * A special node that identifies undefined GPIOs, this is primarily used as
+ * a key for internal chip selects in SPI bindings.
+ */
+const struct software_node swnode_gpio_undefined = {
+	.name = GPIOLIB_SWNODE_UNDEFINED_NAME,
+};
+EXPORT_SYMBOL_NS_GPL(swnode_gpio_undefined, "GPIO_SWNODE");
+
+static int __init swnode_gpio_init(void)
+{
+	int ret;
+
+	ret = software_node_register(&swnode_gpio_undefined);
+	if (ret < 0)
+		pr_err("failed to register swnode: %d\n", ret);
+
+	return ret;
+}
+subsys_initcall(swnode_gpio_init);
+
+static void __exit swnode_gpio_cleanup(void)
+{
+	software_node_unregister(&swnode_gpio_undefined);
 }
+__exitcall(swnode_gpio_cleanup);
+#endif