drivers/mfd/syscon.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * System Control Driver
  *
  * Copyright (C) 2012 Freescale Semiconductor, Inc.
  * Copyright (C) 2012 Linaro Ltd.
  *
  * Author: Dong Aisheng <dong.aisheng@linaro.org>
  */

 #include <linux/clk.h>
 #include <linux/err.h>
 #include <linux/hwspinlock.h>
 #include <linux/io.h>
 #include <linux/init.h>
 #include <linux/list.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/of_platform.h>
 #include <linux/platform_data/syscon.h>
 #include <linux/platform_device.h>
 #include <linux/regmap.h>
 #include <linux/reset.h>
 #include <linux/mfd/syscon.h>
 #include <linux/slab.h>

 static struct platform_driver syscon_driver;

 static DEFINE_SPINLOCK(syscon_list_slock);
 static LIST_HEAD(syscon_list);

 struct syscon {
 	struct device_node *np;
 	struct regmap *regmap;
 	struct reset_control *reset;
 	struct list_head list;
 };

 static const struct regmap_config syscon_regmap_config = {
 	.reg_bits = 32,
 	.val_bits = 32,
 	.reg_stride = 4,
 };

 static struct syscon *of_syscon_register(struct device_node *np, bool check_res)
 {
 	struct clk *clk;
 	struct syscon *syscon;
 	struct regmap *regmap;
 	void __iomem *base;
 	u32 reg_io_width;
 	int ret;
 	struct regmap_config syscon_config = syscon_regmap_config;
 	struct resource res;
 	struct reset_control *reset;

 	syscon = kzalloc(sizeof(*syscon), GFP_KERNEL);
 	if (!syscon)
 		return ERR_PTR(-ENOMEM);

 	if (of_address_to_resource(np, 0, &res)) {
 		ret = -ENOMEM;
 		goto err_map;
 	}

 	base = of_iomap(np, 0);
 	if (!base) {
 		ret = -ENOMEM;
 		goto err_map;
 	}

 	/* Parse the device's DT node for an endianness specification */
 	if (of_property_read_bool(np, "big-endian"))
 		syscon_config.val_format_endian = REGMAP_ENDIAN_BIG;
 	else if (of_property_read_bool(np, "little-endian"))
 		syscon_config.val_format_endian = REGMAP_ENDIAN_LITTLE;
 	else if (of_property_read_bool(np, "native-endian"))
 		syscon_config.val_format_endian = REGMAP_ENDIAN_NATIVE;

 	/*
 	 * search for reg-io-width property in DT. If it is not provided,
 	 * default to 4 bytes. regmap_init_mmio will return an error if values
 	 * are invalid so there is no need to check them here.
 	 */
 	ret = of_property_read_u32(np, "reg-io-width", &reg_io_width);
 	if (ret)
 		reg_io_width = 4;

 	ret = of_hwspin_lock_get_id(np, 0);
 	if (ret > 0 || (IS_ENABLED(CONFIG_HWSPINLOCK) && ret == 0)) {
 		syscon_config.use_hwlock = true;
 		syscon_config.hwlock_id = ret;
 		syscon_config.hwlock_mode = HWLOCK_IRQSTATE;
 	} else if (ret < 0) {
 		switch (ret) {
 		case -ENOENT:
 			/* Ignore missing hwlock, it's optional. */
 			break;
 		default:
 			pr_err("Failed to retrieve valid hwlock: %d\n", ret);
 			fallthrough;
 		case -EPROBE_DEFER:
 			goto err_regmap;
 		}
 	}

 	syscon_config.name = kasprintf(GFP_KERNEL, "%pOFn@%pa", np, &res.start);
 	if (!syscon_config.name) {
 		ret = -ENOMEM;
 		goto err_regmap;
 	}
 	syscon_config.reg_stride = reg_io_width;
 	syscon_config.val_bits = reg_io_width * 8;
 	syscon_config.max_register = resource_size(&res) - reg_io_width;

 	regmap = regmap_init_mmio(NULL, base, &syscon_config);
 	kfree(syscon_config.name);
 	if (IS_ERR(regmap)) {
 		pr_err("regmap init failed\n");
 		ret = PTR_ERR(regmap);
 		goto err_regmap;
 	}

 	if (check_res) {
 		clk = of_clk_get(np, 0);
 		if (IS_ERR(clk)) {
 			ret = PTR_ERR(clk);
 			/* clock is optional */
 			if (ret != -ENOENT)
 				goto err_clk;
 		} else {
 			ret = regmap_mmio_attach_clk(regmap, clk);
 			if (ret)
 				goto err_attach_clk;
 		}

 		reset = of_reset_control_get_optional_exclusive(np, NULL);
 		if (IS_ERR(reset)) {
 			ret = PTR_ERR(reset);
 			goto err_attach_clk;
 		}

 		ret = reset_control_deassert(reset);
 		if (ret)
 			goto err_reset;
 	}

 	syscon->regmap = regmap;
 	syscon->np = np;

 	spin_lock(&syscon_list_slock);
 	list_add_tail(&syscon->list, &syscon_list);
 	spin_unlock(&syscon_list_slock);

 	return syscon;

 err_reset:
 	reset_control_put(reset);
 err_attach_clk:
 	if (!IS_ERR(clk))
 		clk_put(clk);
 err_clk:
 	regmap_exit(regmap);
 err_regmap:
 	iounmap(base);
 err_map:
 	kfree(syscon);
 	return ERR_PTR(ret);
 }

 static struct regmap *device_node_get_regmap(struct device_node *np,
 					     bool check_res)
 {
 	struct syscon *entry, *syscon = NULL;

 	spin_lock(&syscon_list_slock);

 	list_for_each_entry(entry, &syscon_list, list)
 		if (entry->np == np) {
 			syscon = entry;
 			break;
 		}

 	spin_unlock(&syscon_list_slock);

 	if (!syscon)
 		syscon = of_syscon_register(np, check_res);

 	if (IS_ERR(syscon))
 		return ERR_CAST(syscon);

 	return syscon->regmap;
 }

 /**
  * of_syscon_register_regmap() - Register regmap for specified device node
  * @np: Device tree node
  * @regmap: Pointer to regmap object
  *
  * Register an externally created regmap object with syscon for the specified
  * device tree node. This regmap will then be returned to client drivers using
  * the syscon_regmap_lookup_by_phandle() API.
  *
  * Return: 0 on success, negative error code on failure.
  */
 int of_syscon_register_regmap(struct device_node *np, struct regmap *regmap)
 {
 	struct syscon *entry, *syscon = NULL;
 	int ret;

 	if (!np || !regmap)
 		return -EINVAL;

 	syscon = kzalloc(sizeof(*syscon), GFP_KERNEL);
 	if (!syscon)
 		return -ENOMEM;

 	/* check if syscon entry already exists */
 	spin_lock(&syscon_list_slock);

 	list_for_each_entry(entry, &syscon_list, list)
 		if (entry->np == np) {
 			ret = -EEXIST;
 			goto err_unlock;
 		}

 	syscon->regmap = regmap;
 	syscon->np = np;

 	/* register the regmap in syscon list */
 	list_add_tail(&syscon->list, &syscon_list);
 	spin_unlock(&syscon_list_slock);

 	return 0;

 err_unlock:
 	spin_unlock(&syscon_list_slock);
 	kfree(syscon);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(of_syscon_register_regmap);

 struct regmap *device_node_to_regmap(struct device_node *np)
 {
 	return device_node_get_regmap(np, false);
 }
 EXPORT_SYMBOL_GPL(device_node_to_regmap);

 struct regmap *syscon_node_to_regmap(struct device_node *np)
 {
 	if (!of_device_is_compatible(np, "syscon"))
 		return ERR_PTR(-EINVAL);

 	return device_node_get_regmap(np, true);
 }
 EXPORT_SYMBOL_GPL(syscon_node_to_regmap);

 struct regmap *syscon_regmap_lookup_by_compatible(const char *s)
 {
 	struct device_node *syscon_np;
 	struct regmap *regmap;

 	syscon_np = of_find_compatible_node(NULL, NULL, s);
 	if (!syscon_np)
 		return ERR_PTR(-ENODEV);

 	regmap = syscon_node_to_regmap(syscon_np);
 	of_node_put(syscon_np);

 	return regmap;
 }
 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible);

 struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np,
 					const char *property)
 {
 	struct device_node *syscon_np;
 	struct regmap *regmap;

 	if (property)
 		syscon_np = of_parse_phandle(np, property, 0);
 	else
 		syscon_np = np;

 	if (!syscon_np)
 		return ERR_PTR(-ENODEV);

 	regmap = syscon_node_to_regmap(syscon_np);

 	if (property)
 		of_node_put(syscon_np);

 	return regmap;
 }
 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle);

 struct regmap *syscon_regmap_lookup_by_phandle_args(struct device_node *np,
 					const char *property,
 					int arg_count,
 					unsigned int *out_args)
 {
 	struct device_node *syscon_np;
 	struct of_phandle_args args;
 	struct regmap *regmap;
 	unsigned int index;
 	int rc;

 	rc = of_parse_phandle_with_fixed_args(np, property, arg_count,
 			0, &args);
 	if (rc)
 		return ERR_PTR(rc);

 	syscon_np = args.np;
 	if (!syscon_np)
 		return ERR_PTR(-ENODEV);

 	regmap = syscon_node_to_regmap(syscon_np);
 	for (index = 0; index < arg_count; index++)
 		out_args[index] = args.args[index];
 	of_node_put(syscon_np);

 	return regmap;
 }
 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_args);

 /*
  * It behaves the same as syscon_regmap_lookup_by_phandle() except where
  * there is no regmap phandle. In this case, instead of returning -ENODEV,
  * the function returns NULL.
  */
 struct regmap *syscon_regmap_lookup_by_phandle_optional(struct device_node *np,
 					const char *property)
 {
 	struct regmap *regmap;

 	regmap = syscon_regmap_lookup_by_phandle(np, property);
 	if (IS_ERR(regmap) && PTR_ERR(regmap) == -ENODEV)
 		return NULL;

 	return regmap;
 }
 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_optional);

 static int syscon_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct syscon_platform_data *pdata = dev_get_platdata(dev);
 	struct syscon *syscon;
 	struct regmap_config syscon_config = syscon_regmap_config;
 	struct resource *res;
 	void __iomem *base;

 	syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL);
 	if (!syscon)
 		return -ENOMEM;

 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (!res)
 		return -ENOENT;

 	base = devm_ioremap(dev, res->start, resource_size(res));
 	if (!base)
 		return -ENOMEM;

 	syscon_config.max_register = resource_size(res) - 4;
 	if (pdata)
 		syscon_config.name = pdata->label;
 	syscon->regmap = devm_regmap_init_mmio(dev, base, &syscon_config);
 	if (IS_ERR(syscon->regmap)) {
 		dev_err(dev, "regmap init failed\n");
 		return PTR_ERR(syscon->regmap);
 	}

 	platform_set_drvdata(pdev, syscon);

 	dev_dbg(dev, "regmap %pR registered\n", res);

 	return 0;
 }

 static const struct platform_device_id syscon_ids[] = {
 	{ "syscon", },
 	{ }
 };

 static struct platform_driver syscon_driver = {
 	.driver = {
 		.name = "syscon",
 	},
 	.probe		= syscon_probe,
 	.id_table	= syscon_ids,
 };

 static int __init syscon_init(void)
 {
 	return platform_driver_register(&syscon_driver);
 }
 postcore_initcall(syscon_init);
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* System Control Driver
	*
	* Copyright (C) 2012 Freescale Semiconductor, Inc.
	* Copyright (C) 2012 Linaro Ltd.
	*
	* Author: Dong Aisheng <dong.aisheng@linaro.org>
	*/

	#include <linux/clk.h>
	#include <linux/err.h>
	#include <linux/hwspinlock.h>
	#include <linux/io.h>
	#include <linux/init.h>
	#include <linux/list.h>
	#include <linux/of.h>
	#include <linux/of_address.h>
	#include <linux/of_platform.h>
	#include <linux/platform_data/syscon.h>
	#include <linux/platform_device.h>
	#include <linux/regmap.h>
	#include <linux/reset.h>
	#include <linux/mfd/syscon.h>
	#include <linux/slab.h>

	static struct platform_driver syscon_driver;

	static DEFINE_SPINLOCK(syscon_list_slock);
	static LIST_HEAD(syscon_list);

	struct syscon {
	struct device_node *np;
	struct regmap *regmap;
	struct reset_control *reset;
	struct list_head list;
	};

	static const struct regmap_config syscon_regmap_config = {
	.reg_bits = 32,
	.val_bits = 32,
	.reg_stride = 4,
	};

	static struct syscon of_syscon_register(struct device_node np, bool check_res)
	{
	struct clk *clk;
	struct syscon *syscon;
	struct regmap *regmap;
	void __iomem *base;
	u32 reg_io_width;
	int ret;
	struct regmap_config syscon_config = syscon_regmap_config;
	struct resource res;
	struct reset_control *reset;

	syscon = kzalloc(sizeof(*syscon), GFP_KERNEL);
	if (!syscon)
	return ERR_PTR(-ENOMEM);

	if (of_address_to_resource(np, 0, &res)) {
	ret = -ENOMEM;
	goto err_map;
	}

	base = of_iomap(np, 0);
	if (!base) {
	ret = -ENOMEM;
	goto err_map;
	}

	/* Parse the device's DT node for an endianness specification */
	if (of_property_read_bool(np, "big-endian"))
	syscon_config.val_format_endian = REGMAP_ENDIAN_BIG;
	else if (of_property_read_bool(np, "little-endian"))
	syscon_config.val_format_endian = REGMAP_ENDIAN_LITTLE;
	else if (of_property_read_bool(np, "native-endian"))
	syscon_config.val_format_endian = REGMAP_ENDIAN_NATIVE;

	/*
	* search for reg-io-width property in DT. If it is not provided,
	* default to 4 bytes. regmap_init_mmio will return an error if values
	* are invalid so there is no need to check them here.
	*/
	ret = of_property_read_u32(np, "reg-io-width", &reg_io_width);
	if (ret)
	reg_io_width = 4;

	ret = of_hwspin_lock_get_id(np, 0);
	if (ret > 0 \|\| (IS_ENABLED(CONFIG_HWSPINLOCK) && ret == 0)) {
	syscon_config.use_hwlock = true;
	syscon_config.hwlock_id = ret;
	syscon_config.hwlock_mode = HWLOCK_IRQSTATE;
	} else if (ret < 0) {
	switch (ret) {
	case -ENOENT:
	/* Ignore missing hwlock, it's optional. */
	break;
	default:
	pr_err("Failed to retrieve valid hwlock: %d\n", ret);
	fallthrough;
	case -EPROBE_DEFER:
	goto err_regmap;
	}
	}

	syscon_config.name = kasprintf(GFP_KERNEL, "%pOFn@%pa", np, &res.start);
	if (!syscon_config.name) {
	ret = -ENOMEM;
	goto err_regmap;
	}
	syscon_config.reg_stride = reg_io_width;
	syscon_config.val_bits = reg_io_width * 8;
	syscon_config.max_register = resource_size(&res) - reg_io_width;

	regmap = regmap_init_mmio(NULL, base, &syscon_config);
	kfree(syscon_config.name);
	if (IS_ERR(regmap)) {
	pr_err("regmap init failed\n");
	ret = PTR_ERR(regmap);
	goto err_regmap;
	}

	if (check_res) {
	clk = of_clk_get(np, 0);
	if (IS_ERR(clk)) {
	ret = PTR_ERR(clk);
	/* clock is optional */
	if (ret != -ENOENT)
	goto err_clk;
	} else {
	ret = regmap_mmio_attach_clk(regmap, clk);
	if (ret)
	goto err_attach_clk;
	}

	reset = of_reset_control_get_optional_exclusive(np, NULL);
	if (IS_ERR(reset)) {
	ret = PTR_ERR(reset);
	goto err_attach_clk;
	}

	ret = reset_control_deassert(reset);
	if (ret)
	goto err_reset;
	}

	syscon->regmap = regmap;
	syscon->np = np;

	spin_lock(&syscon_list_slock);
	list_add_tail(&syscon->list, &syscon_list);
	spin_unlock(&syscon_list_slock);

	return syscon;

	err_reset:
	reset_control_put(reset);
	err_attach_clk:
	if (!IS_ERR(clk))
	clk_put(clk);
	err_clk:
	regmap_exit(regmap);
	err_regmap:
	iounmap(base);
	err_map:
	kfree(syscon);
	return ERR_PTR(ret);
	}

	static struct regmap device_node_get_regmap(struct device_node np,
	bool check_res)
	{
	struct syscon entry, syscon = NULL;

	spin_lock(&syscon_list_slock);

	list_for_each_entry(entry, &syscon_list, list)
	if (entry->np == np) {
	syscon = entry;
	break;
	}

	spin_unlock(&syscon_list_slock);

	if (!syscon)
	syscon = of_syscon_register(np, check_res);

	if (IS_ERR(syscon))
	return ERR_CAST(syscon);

	return syscon->regmap;
	}

	/**
	* of_syscon_register_regmap() - Register regmap for specified device node
	* @np: Device tree node
	* @regmap: Pointer to regmap object
	*
	* Register an externally created regmap object with syscon for the specified
	* device tree node. This regmap will then be returned to client drivers using
	* the syscon_regmap_lookup_by_phandle() API.
	*
	* Return: 0 on success, negative error code on failure.
	*/
	int of_syscon_register_regmap(struct device_node np, struct regmap regmap)
	{
	struct syscon entry, syscon = NULL;
	int ret;

	if (!np \|\| !regmap)
	return -EINVAL;

	syscon = kzalloc(sizeof(*syscon), GFP_KERNEL);
	if (!syscon)
	return -ENOMEM;

	/* check if syscon entry already exists */
	spin_lock(&syscon_list_slock);

	list_for_each_entry(entry, &syscon_list, list)
	if (entry->np == np) {
	ret = -EEXIST;
	goto err_unlock;
	}

	syscon->regmap = regmap;
	syscon->np = np;

	/* register the regmap in syscon list */
	list_add_tail(&syscon->list, &syscon_list);
	spin_unlock(&syscon_list_slock);

	return 0;

	err_unlock:
	spin_unlock(&syscon_list_slock);
	kfree(syscon);
	return ret;
	}
	EXPORT_SYMBOL_GPL(of_syscon_register_regmap);

	struct regmap device_node_to_regmap(struct device_node np)
	{
	return device_node_get_regmap(np, false);
	}
	EXPORT_SYMBOL_GPL(device_node_to_regmap);

	struct regmap syscon_node_to_regmap(struct device_node np)
	{
	if (!of_device_is_compatible(np, "syscon"))
	return ERR_PTR(-EINVAL);

	return device_node_get_regmap(np, true);
	}
	EXPORT_SYMBOL_GPL(syscon_node_to_regmap);

	struct regmap syscon_regmap_lookup_by_compatible(const char s)
	{
	struct device_node *syscon_np;
	struct regmap *regmap;

	syscon_np = of_find_compatible_node(NULL, NULL, s);
	if (!syscon_np)
	return ERR_PTR(-ENODEV);

	regmap = syscon_node_to_regmap(syscon_np);
	of_node_put(syscon_np);

	return regmap;
	}
	EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible);

	struct regmap syscon_regmap_lookup_by_phandle(struct device_node np,
	const char *property)
	{
	struct device_node *syscon_np;
	struct regmap *regmap;

	if (property)
	syscon_np = of_parse_phandle(np, property, 0);
	else
	syscon_np = np;

	if (!syscon_np)
	return ERR_PTR(-ENODEV);

	regmap = syscon_node_to_regmap(syscon_np);

	if (property)
	of_node_put(syscon_np);

	return regmap;
	}
	EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle);

	struct regmap syscon_regmap_lookup_by_phandle_args(struct device_node np,
	const char *property,
	int arg_count,
	unsigned int *out_args)
	{
	struct device_node *syscon_np;
	struct of_phandle_args args;
	struct regmap *regmap;
	unsigned int index;
	int rc;

	rc = of_parse_phandle_with_fixed_args(np, property, arg_count,
	0, &args);
	if (rc)
	return ERR_PTR(rc);

	syscon_np = args.np;
	if (!syscon_np)
	return ERR_PTR(-ENODEV);

	regmap = syscon_node_to_regmap(syscon_np);
	for (index = 0; index < arg_count; index++)
	out_args[index] = args.args[index];
	of_node_put(syscon_np);

	return regmap;
	}
	EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_args);

	/*
	* It behaves the same as syscon_regmap_lookup_by_phandle() except where
	* there is no regmap phandle. In this case, instead of returning -ENODEV,
	* the function returns NULL.
	*/
	struct regmap syscon_regmap_lookup_by_phandle_optional(struct device_node np,
	const char *property)
	{
	struct regmap *regmap;

	regmap = syscon_regmap_lookup_by_phandle(np, property);
	if (IS_ERR(regmap) && PTR_ERR(regmap) == -ENODEV)
	return NULL;

	return regmap;
	}
	EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_optional);

	static int syscon_probe(struct platform_device *pdev)
	{
	struct device *dev = &pdev->dev;
	struct syscon_platform_data *pdata = dev_get_platdata(dev);
	struct syscon *syscon;
	struct regmap_config syscon_config = syscon_regmap_config;
	struct resource *res;
	void __iomem *base;

	syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL);
	if (!syscon)
	return -ENOMEM;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res)
	return -ENOENT;

	base = devm_ioremap(dev, res->start, resource_size(res));
	if (!base)
	return -ENOMEM;

	syscon_config.max_register = resource_size(res) - 4;
	if (pdata)
	syscon_config.name = pdata->label;
	syscon->regmap = devm_regmap_init_mmio(dev, base, &syscon_config);
	if (IS_ERR(syscon->regmap)) {
	dev_err(dev, "regmap init failed\n");
	return PTR_ERR(syscon->regmap);
	}

	platform_set_drvdata(pdev, syscon);

	dev_dbg(dev, "regmap %pR registered\n", res);

	return 0;
	}

	static const struct platform_device_id syscon_ids[] = {
	{ "syscon", },
	{ }
	};

	static struct platform_driver syscon_driver = {
	.driver = {
	.name = "syscon",
	},
	.probe = syscon_probe,
	.id_table = syscon_ids,
	};

	static int __init syscon_init(void)
	{
	return platform_driver_register(&syscon_driver);
	}
	postcore_initcall(syscon_init);