Merge tag 'reset-gpio-for-v6.19' of https://git.pengutronix.de/git/pza/linux into soc/drivers-late

Reset/GPIO/swnode changes for v6.19

* Extend software node implementation, allowing its properties to reference
  existing firmware nodes.
* Update the GPIO property interface to use reworked swnode macros.
* Rework reset-gpio code to use GPIO lookup via swnode.
* Fix spi-cs42l43 driver to work with swnode changes.

* tag 'reset-gpio-for-v6.19' of https://git.pengutronix.de/git/pza/linux:
  reset: gpio: use software nodes to setup the GPIO lookup
  reset: gpio: convert the driver to using the auxiliary bus
  reset: make the provider of reset-gpios the parent of the reset device
  reset: order includes alphabetically in reset/core.c
  gpio: swnode: allow referencing GPIO chips by firmware nodes
  spi: cs42l43: Use actual ACPI firmware node for chip selects
  software node: allow referencing firmware nodes
  software node: increase the reference of the swnode by its fwnode
  software node: read the reference args via the fwnode API

Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Author: arndb

drivers/base/swnode.c

@@ -535,14 +535,29 @@ software_node_get_reference_args(const struct fwnode_handle *fwnode,
 	ref_array = prop->pointer;
 	ref = &ref_array[index];
 
-	refnode = software_node_fwnode(ref->node);
+	/*
+	 * A software node can reference other software nodes or firmware
+	 * nodes (which are the abstraction layer sitting on top of them).
+	 * This is done to ensure we can create references to static software
+	 * nodes before they're registered with the firmware node framework.
+	 * At the time the reference is being resolved, we expect the swnodes
+	 * in question to already have been registered and to be backed by
+	 * a firmware node. This is why we use the fwnode API below to read the
+	 * relevant properties and bump the reference count.
+	 */
+
+	if (ref->swnode)
+		refnode = software_node_fwnode(ref->swnode);
+	else if (ref->fwnode)
+		refnode = ref->fwnode;
+	else
+		return -EINVAL;
+
 	if (!refnode)
 		return -ENOENT;
 
 	if (nargs_prop) {
-		error = property_entry_read_int_array(ref->node->properties,
-						      nargs_prop, sizeof(u32),
-						      &nargs_prop_val, 1);
+		error = fwnode_property_read_u32(refnode, nargs_prop, &nargs_prop_val);
 		if (error)
 			return error;
 
@@ -555,7 +570,7 @@ software_node_get_reference_args(const struct fwnode_handle *fwnode,
 	if (!args)
 		return 0;
 
-	args->fwnode = software_node_get(refnode);
+	args->fwnode = fwnode_handle_get(refnode);
 	args->nargs = nargs;
 
 	for (i = 0; i < nargs; i++)
@@ -635,7 +650,10 @@ software_node_graph_get_remote_endpoint(const struct fwnode_handle *fwnode)
 
 	ref = prop->pointer;
 
-	return software_node_get(software_node_fwnode(ref[0].node));
+	if (!ref->swnode)
+		return NULL;
+
+	return software_node_get(software_node_fwnode(ref->swnode));
 }
 
 static struct fwnode_handle *

drivers/gpio/gpiolib-swnode.c

@@ -31,7 +31,7 @@ static struct gpio_device *swnode_get_gpio_device(struct fwnode_handle *fwnode)
 
 	gdev_node = to_software_node(fwnode);
 	if (!gdev_node || !gdev_node->name)
-		return ERR_PTR(-EINVAL);
+		goto fwnode_lookup;
 
 	/*
 	 * Check for a special node that identifies undefined GPIOs, this is
@@ -41,6 +41,7 @@ static struct gpio_device *swnode_get_gpio_device(struct fwnode_handle *fwnode)
 	    !strcmp(gdev_node->name, GPIOLIB_SWNODE_UNDEFINED_NAME))
 		return ERR_PTR(-ENOENT);
 
+fwnode_lookup:
 	gdev = gpio_device_find_by_fwnode(fwnode);
 	return gdev ?: ERR_PTR(-EPROBE_DEFER);
 }

drivers/reset/Kconfig

@@ -89,6 +89,7 @@ config RESET_EYEQ
 config RESET_GPIO
 	tristate "GPIO reset controller"
 	depends on GPIOLIB
+	select AUXILIARY_BUS
 	help
 	  This enables a generic reset controller for resets attached via
 	  GPIOs.  Typically for OF platforms this driver expects "reset-gpios"

drivers/reset/core.c

@@ -4,20 +4,22 @@
  *
  * Copyright 2013 Philipp Zabel, Pengutronix
  */
+
+#include <linux/acpi.h>
 #include <linux/atomic.h>
+#include <linux/auxiliary_bus.h>
 #include <linux/cleanup.h>
 #include <linux/device.h>
 #include <linux/err.h>
 #include <linux/export.h>
-#include <linux/kernel.h>
-#include <linux/kref.h>
 #include <linux/gpio/driver.h>
 #include <linux/gpio/machine.h>
+#include <linux/gpio/property.h>
 #include <linux/idr.h>
+#include <linux/kernel.h>
+#include <linux/kref.h>
 #include <linux/module.h>
 #include <linux/of.h>
-#include <linux/acpi.h>
-#include <linux/platform_device.h>
 #include <linux/reset.h>
 #include <linux/reset-controller.h>
 #include <linux/slab.h>
@@ -76,10 +78,12 @@ struct reset_control_array {
 /**
  * struct reset_gpio_lookup - lookup key for ad-hoc created reset-gpio devices
  * @of_args: phandle to the reset controller with all the args like GPIO number
+ * @swnode: Software node containing the reference to the GPIO provider
  * @list: list entry for the reset_gpio_lookup_list
  */
 struct reset_gpio_lookup {
 	struct of_phandle_args of_args;
+	struct fwnode_handle *swnode;
 	struct list_head list;
 };
 
@@ -848,65 +852,56 @@ static void __reset_control_put_internal(struct reset_control *rstc)
 	kref_put(&rstc->refcnt, __reset_control_release);
 }
 
-static int __reset_add_reset_gpio_lookup(int id, struct device_node *np,
-					 unsigned int gpio,
-					 unsigned int of_flags)
+static void reset_gpio_aux_device_release(struct device *dev)
 {
-	const struct fwnode_handle *fwnode = of_fwnode_handle(np);
-	unsigned int lookup_flags;
-	const char *label_tmp;
+	struct auxiliary_device *adev = to_auxiliary_dev(dev);
 
-	/*
-	 * Later we map GPIO flags between OF and Linux, however not all
-	 * constants from include/dt-bindings/gpio/gpio.h and
-	 * include/linux/gpio/machine.h match each other.
-	 */
-	if (of_flags > GPIO_ACTIVE_LOW) {
-		pr_err("reset-gpio code does not support GPIO flags %u for GPIO %u\n",
-		       of_flags, gpio);
-		return -EINVAL;
-	}
-
-	struct gpio_device *gdev __free(gpio_device_put) = gpio_device_find_by_fwnode(fwnode);
-	if (!gdev)
-		return -EPROBE_DEFER;
-
-	label_tmp = gpio_device_get_label(gdev);
-	if (!label_tmp)
-		return -EINVAL;
+	kfree(adev);
+}
 
-	char *label __free(kfree) = kstrdup(label_tmp, GFP_KERNEL);
-	if (!label)
-		return -ENOMEM;
+static int reset_add_gpio_aux_device(struct device *parent,
+				     struct fwnode_handle *swnode,
+				     int id, void *pdata)
+{
+	struct auxiliary_device *adev;
+	int ret;
 
-	/* Size: one lookup entry plus sentinel */
-	struct gpiod_lookup_table *lookup __free(kfree) = kzalloc(struct_size(lookup, table, 2),
-								  GFP_KERNEL);
-	if (!lookup)
+	adev = kzalloc(sizeof(*adev), GFP_KERNEL);
+	if (!adev)
 		return -ENOMEM;
 
-	lookup->dev_id = kasprintf(GFP_KERNEL, "reset-gpio.%d", id);
-	if (!lookup->dev_id)
-		return -ENOMEM;
+	adev->id = id;
+	adev->name = "gpio";
+	adev->dev.parent = parent;
+	adev->dev.platform_data = pdata;
+	adev->dev.release = reset_gpio_aux_device_release;
+	device_set_node(&adev->dev, swnode);
 
-	lookup_flags = GPIO_PERSISTENT;
-	lookup_flags |= of_flags & GPIO_ACTIVE_LOW;
-	lookup->table[0] = GPIO_LOOKUP(no_free_ptr(label), gpio, "reset",
-				       lookup_flags);
+	ret = auxiliary_device_init(adev);
+	if (ret) {
+		kfree(adev);
+		return ret;
+	}
 
-	/* Not freed on success, because it is persisent subsystem data. */
-	gpiod_add_lookup_table(no_free_ptr(lookup));
+	ret = __auxiliary_device_add(adev, "reset");
+	if (ret) {
+		auxiliary_device_uninit(adev);
+		kfree(adev);
+		return ret;
+	}
 
-	return 0;
+	return ret;
 }
 
 /*
  * @args:	phandle to the GPIO provider with all the args like GPIO number
  */
 static int __reset_add_reset_gpio_device(const struct of_phandle_args *args)
 {
+	struct property_entry properties[2] = { };
+	unsigned int offset, of_flags, lflags;
 	struct reset_gpio_lookup *rgpio_dev;
-	struct platform_device *pdev;
+	struct device *parent;
 	int id, ret;
 
 	/*
@@ -925,6 +920,28 @@ static int __reset_add_reset_gpio_device(const struct of_phandle_args *args)
 	 */
 	lockdep_assert_not_held(&reset_list_mutex);
 
+	offset = args->args[0];
+	of_flags = args->args[1];
+
+	/*
+	 * Later we map GPIO flags between OF and Linux, however not all
+	 * constants from include/dt-bindings/gpio/gpio.h and
+	 * include/linux/gpio/machine.h match each other.
+	 *
+	 * FIXME: Find a better way of translating OF flags to GPIO lookup
+	 * flags.
+	 */
+	if (of_flags > GPIO_ACTIVE_LOW) {
+		pr_err("reset-gpio code does not support GPIO flags %u for GPIO %u\n",
+		       of_flags, offset);
+		return -EINVAL;
+	}
+
+	struct gpio_device *gdev __free(gpio_device_put) =
+		gpio_device_find_by_fwnode(of_fwnode_handle(args->np));
+	if (!gdev)
+		return -EPROBE_DEFER;
+
 	guard(mutex)(&reset_gpio_lookup_mutex);
 
 	list_for_each_entry(rgpio_dev, &reset_gpio_lookup_list, list) {
@@ -934,6 +951,10 @@ static int __reset_add_reset_gpio_device(const struct of_phandle_args *args)
 		}
 	}
 
+	lflags = GPIO_PERSISTENT | (of_flags & GPIO_ACTIVE_LOW);
+	parent = gpio_device_to_device(gdev);
+	properties[0] = PROPERTY_ENTRY_GPIO("reset-gpios", parent->fwnode, offset, lflags);
+
 	id = ida_alloc(&reset_gpio_ida, GFP_KERNEL);
 	if (id < 0)
 		return id;
@@ -945,32 +966,33 @@ static int __reset_add_reset_gpio_device(const struct of_phandle_args *args)
 		goto err_ida_free;
 	}
 
-	ret = __reset_add_reset_gpio_lookup(id, args->np, args->args[0],
-					    args->args[1]);
-	if (ret < 0)
-		goto err_kfree;
-
 	rgpio_dev->of_args = *args;
 	/*
 	 * We keep the device_node reference, but of_args.np is put at the end
 	 * of __of_reset_control_get(), so get it one more time.
 	 * Hold reference as long as rgpio_dev memory is valid.
 	 */
 	of_node_get(rgpio_dev->of_args.np);
-	pdev = platform_device_register_data(NULL, "reset-gpio", id,
-					     &rgpio_dev->of_args,
-					     sizeof(rgpio_dev->of_args));
-	ret = PTR_ERR_OR_ZERO(pdev);
+
+	rgpio_dev->swnode = fwnode_create_software_node(properties, NULL);
+	if (IS_ERR(rgpio_dev->swnode)) {
+		ret = PTR_ERR(rgpio_dev->swnode);
+		goto err_put_of_node;
+	}
+
+	ret = reset_add_gpio_aux_device(parent, rgpio_dev->swnode, id,
+					&rgpio_dev->of_args);
 	if (ret)
-		goto err_put;
+		goto err_del_swnode;
 
 	list_add(&rgpio_dev->list, &reset_gpio_lookup_list);
 
 	return 0;
 
-err_put:
+err_del_swnode:
+	fwnode_remove_software_node(rgpio_dev->swnode);
+err_put_of_node:
 	of_node_put(rgpio_dev->of_args.np);
-err_kfree:
 	kfree(rgpio_dev);
 err_ida_free:
 	ida_free(&reset_gpio_ida, id);

drivers/reset/reset-gpio.c

@@ -1,10 +1,10 @@
 // SPDX-License-Identifier: GPL-2.0
 
+#include <linux/auxiliary_bus.h>
 #include <linux/gpio/consumer.h>
 #include <linux/mod_devicetable.h>
 #include <linux/module.h>
 #include <linux/of.h>
-#include <linux/platform_device.h>
 #include <linux/reset-controller.h>
 
 struct reset_gpio_priv {
@@ -61,9 +61,10 @@ static void reset_gpio_of_node_put(void *data)
 	of_node_put(data);
 }
 
-static int reset_gpio_probe(struct platform_device *pdev)
+static int reset_gpio_probe(struct auxiliary_device *adev,
+			    const struct auxiliary_device_id *id)
 {
-	struct device *dev = &pdev->dev;
+	struct device *dev = &adev->dev;
 	struct of_phandle_args *platdata = dev_get_platdata(dev);
 	struct reset_gpio_priv *priv;
 	int ret;
@@ -75,7 +76,7 @@ static int reset_gpio_probe(struct platform_device *pdev)
 	if (!priv)
 		return -ENOMEM;
 
-	platform_set_drvdata(pdev, &priv->rc);
+	auxiliary_set_drvdata(adev, &priv->rc);
 
 	priv->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
 	if (IS_ERR(priv->reset))
@@ -99,20 +100,20 @@ static int reset_gpio_probe(struct platform_device *pdev)
 	return devm_reset_controller_register(dev, &priv->rc);
 }
 
-static const struct platform_device_id reset_gpio_ids[] = {
-	{ .name = "reset-gpio", },
+static const struct auxiliary_device_id reset_gpio_ids[] = {
+	{ .name = "reset.gpio" },
 	{}
 };
-MODULE_DEVICE_TABLE(platform, reset_gpio_ids);
+MODULE_DEVICE_TABLE(auxiliary, reset_gpio_ids);
 
-static struct platform_driver reset_gpio_driver = {
+static struct auxiliary_driver reset_gpio_driver = {
 	.probe		= reset_gpio_probe,
 	.id_table	= reset_gpio_ids,
 	.driver	= {
 		.name = "reset-gpio",
 	},
 };
-module_platform_driver(reset_gpio_driver);
+module_auxiliary_driver(reset_gpio_driver);
 
 MODULE_AUTHOR("Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>");
 MODULE_DESCRIPTION("Generic GPIO reset driver");