[linux-block.git] / drivers / gpio / gpiolib-swnode.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * Software Node helpers for the GPIO API
 *
 * Copyright 2022 Google LLC
 */
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/printk.h>
#include <linux/property.h>
#include <linux/string.h>

#include <linux/gpio/consumer.h>
#include <linux/gpio/driver.h>

#include "gpiolib.h"
#include "gpiolib-swnode.h"

static void swnode_format_propname(const char *con_id, char *propname,
				   size_t max_size)
{
	/*
	 * 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.
	 */
	if (con_id)
		snprintf(propname, max_size, "%s-gpios", con_id);
	else
		strscpy(propname, "gpios", max_size);
}

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)
		return ERR_PTR(-EINVAL);

	gdev = gpio_device_find_by_label(gdev_node->name);
	return gdev ?: ERR_PTR(-EPROBE_DEFER);
}

struct gpio_desc *swnode_find_gpio(struct fwnode_handle *fwnode,
				   const char *con_id, unsigned int idx,
				   unsigned long *flags)
{
	const struct software_node *swnode;
	struct fwnode_reference_args args;
	struct gpio_desc *desc;
	char propname[32]; /* 32 is max size of property name */
	int error;

	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) {
		pr_debug("%s: can't parse '%s' property of node '%pfwP[%d]'\n",
			__func__, propname, fwnode, idx);
		return ERR_PTR(error);
	}

	struct gpio_device *gdev __free(gpio_device_put) =
					swnode_get_gpio_device(args.fwnode);
	fwnode_handle_put(args.fwnode);
	if (IS_ERR(gdev))
		return ERR_CAST(gdev);

	/*
	 * 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",
		 __func__, propname, fwnode, idx, PTR_ERR_OR_ZERO(desc));

	return desc;
}

/**
 * swnode_gpio_count - count the GPIOs associated with a device / function
 * @fwnode:	firmware node of the GPIO consumer, can be %NULL for
 *		system-global GPIOs
 * @con_id:	function within the GPIO consumer
 *
 * Return:
 * The number of GPIOs associated with a device / function or %-ENOENT,
 * if no GPIO has been assigned to the requested function.
 */
int swnode_gpio_count(const struct fwnode_handle *fwnode, const char *con_id)
{
	struct fwnode_reference_args args;
	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++;
	}

	return count ?: -ENOENT;
}
Commit	Line	Data
e7f9ff5d DT	1	// SPDX-License-Identifier: GPL-2.0+
	2	/*
	3	* Software Node helpers for the GPIO API
	4	*
	5	* Copyright 2022 Google LLC
	6	*/
	7	#include <linux/err.h>
	8	#include <linux/errno.h>
e7f9ff5d DT	9	#include <linux/kernel.h>
	10	#include <linux/printk.h>
	11	#include <linux/property.h>
	12	#include <linux/string.h>
	13
380c7ba3 AS	14	#include <linux/gpio/consumer.h>
	15	#include <linux/gpio/driver.h>
	16
e7f9ff5d DT	17	#include "gpiolib.h"
	18	#include "gpiolib-swnode.h"
	19
	20	static void swnode_format_propname(const char con_id, char propname,
	21	size_t max_size)
	22	{
	23	/*
	24	* Note we do not need to try both -gpios and -gpio suffixes,
	25	* as, unlike OF and ACPI, we can fix software nodes to conform
	26	* to the proper binding.
	27	*/
	28	if (con_id)
	29	snprintf(propname, max_size, "%s-gpios", con_id);
	30	else
	31	strscpy(propname, "gpios", max_size);
	32	}
	33
b7b56e64	34	static struct gpio_device swnode_get_gpio_device(struct fwnode_handle fwnode)
e7f9ff5d	35	{
b7b56e64 BG	36	const struct software_node *gdev_node;
b7b56e64 BG	37	struct gpio_device *gdev;
e7f9ff5d	38
b7b56e64 BG	39	gdev_node = to_software_node(fwnode);
b7b56e64 BG	40	if (!gdev_node \|\| !gdev_node->name)
e7f9ff5d DT	41	return ERR_PTR(-EINVAL);
e7f9ff5d DT	42
b7b56e64 BG	43	gdev = gpio_device_find_by_label(gdev_node->name);
b7b56e64 BG	44	return gdev ?: ERR_PTR(-EPROBE_DEFER);
e7f9ff5d DT	45	}
	46
	47	struct gpio_desc swnode_find_gpio(struct fwnode_handle fwnode,
	48	const char *con_id, unsigned int idx,
	49	unsigned long *flags)
	50	{
	51	const struct software_node *swnode;
	52	struct fwnode_reference_args args;
e7f9ff5d DT	53	struct gpio_desc *desc;
	54	char propname[32]; /* 32 is max size of property name */
	55	int error;
	56
	57	swnode = to_software_node(fwnode);
	58	if (!swnode)
	59	return ERR_PTR(-EINVAL);
	60
	61	swnode_format_propname(con_id, propname, sizeof(propname));
	62
	63	/*
	64	* We expect all swnode-described GPIOs have GPIO number and
	65	* polarity arguments, hence nargs is set to 2.
	66	*/
	67	error = fwnode_property_get_reference_args(fwnode, propname, NULL, 2, idx, &args);
	68	if (error) {
	69	pr_debug("%s: can't parse '%s' property of node '%pfwP[%d]'\n",
	70	__func__, propname, fwnode, idx);
	71	return ERR_PTR(error);
	72	}
	73
b7b56e64 BG	74	struct gpio_device *gdev __free(gpio_device_put) =
b7b56e64 BG	75	swnode_get_gpio_device(args.fwnode);
e7f9ff5d	76	fwnode_handle_put(args.fwnode);
b7b56e64 BG	77	if (IS_ERR(gdev))
b7b56e64 BG	78	return ERR_CAST(gdev);
e7f9ff5d	79
b7b56e64 BG	80	/*
	81	* FIXME: The GPIO device reference is put at return but the descriptor
	82	* is passed on. Find a proper solution.
	83	*/
	84	desc = gpio_device_get_desc(gdev, args.args[0]);
e7f9ff5d DT	85	flags = args.args[1]; / We expect native GPIO flags */
	86
	87	pr_debug("%s: parsed '%s' property of node '%pfwP[%d]' - status (%d)\n",
	88	__func__, propname, fwnode, idx, PTR_ERR_OR_ZERO(desc));
	89
	90	return desc;
	91	}
	92
	93	/**
	94	* swnode_gpio_count - count the GPIOs associated with a device / function
	95	* @fwnode: firmware node of the GPIO consumer, can be %NULL for
	96	* system-global GPIOs
	97	* @con_id: function within the GPIO consumer
	98	*
	99	* Return:
	100	* The number of GPIOs associated with a device / function or %-ENOENT,
	101	* if no GPIO has been assigned to the requested function.
	102	*/
	103	int swnode_gpio_count(const struct fwnode_handle fwnode, const char con_id)
	104	{
	105	struct fwnode_reference_args args;
	106	char propname[32];
	107	int count;
	108
	109	swnode_format_propname(con_id, propname, sizeof(propname));
	110
	111	/*
	112	* This is not very efficient, but GPIO lists usually have only
	113	* 1 or 2 entries.
	114	*/
	115	count = 0;
	116	while (fwnode_property_get_reference_args(fwnode, propname, NULL, 0,
	117	count, &args) == 0) {
	118	fwnode_handle_put(args.fwnode);
	119	count++;
	120	}
	121
	122	return count ?: -ENOENT;
	123	}