1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * System Control Driver
  4 *
  5 * Copyright (C) 2012 Freescale Semiconductor, Inc.
  6 * Copyright (C) 2012 Linaro Ltd.
  7 *
  8 * Author: Dong Aisheng <dong.aisheng@linaro.org>
  9 */
 10
 11#include <linux/clk.h>
 12#include <linux/err.h>
 13#include <linux/hwspinlock.h>
 14#include <linux/io.h>
 15#include <linux/init.h>
 16#include <linux/list.h>
 17#include <linux/of.h>
 18#include <linux/of_address.h>
 19#include <linux/of_platform.h>
 20#include <linux/platform_data/syscon.h>
 21#include <linux/platform_device.h>
 22#include <linux/regmap.h>
 23#include <linux/mfd/syscon.h>
 24#include <linux/slab.h>
 25
 26static struct platform_driver syscon_driver;
 27
 28static DEFINE_SPINLOCK(syscon_list_slock);
 29static LIST_HEAD(syscon_list);
 30
 31struct syscon {
 32	struct device_node *np;
 33	struct regmap *regmap;
 34	struct list_head list;
 35};
 36
 37static const struct regmap_config syscon_regmap_config = {
 38	.reg_bits = 32,
 39	.val_bits = 32,
 40	.reg_stride = 4,
 41};
 42
 43static struct syscon *of_syscon_register(struct device_node *np, bool check_clk)
 44{
 45	struct clk *clk;
 46	struct syscon *syscon;
 47	struct regmap *regmap;
 48	void __iomem *base;
 49	u32 reg_io_width;
 50	int ret;
 51	struct regmap_config syscon_config = syscon_regmap_config;
 52	struct resource res;
 53
 54	syscon = kzalloc(sizeof(*syscon), GFP_KERNEL);
 55	if (!syscon)
 56		return ERR_PTR(-ENOMEM);
 57
 58	if (of_address_to_resource(np, 0, &res)) {
 59		ret = -ENOMEM;
 60		goto err_map;
 61	}
 62
 63	base = ioremap(res.start, resource_size(&res));
 64	if (!base) {
 65		ret = -ENOMEM;
 66		goto err_map;
 67	}
 68
 69	/* Parse the device's DT node for an endianness specification */
 70	if (of_property_read_bool(np, "big-endian"))
 71		syscon_config.val_format_endian = REGMAP_ENDIAN_BIG;
 72	else if (of_property_read_bool(np, "little-endian"))
 73		syscon_config.val_format_endian = REGMAP_ENDIAN_LITTLE;
 74	else if (of_property_read_bool(np, "native-endian"))
 75		syscon_config.val_format_endian = REGMAP_ENDIAN_NATIVE;
 76
 77	/*
 78	 * search for reg-io-width property in DT. If it is not provided,
 79	 * default to 4 bytes. regmap_init_mmio will return an error if values
 80	 * are invalid so there is no need to check them here.
 81	 */
 82	ret = of_property_read_u32(np, "reg-io-width", &reg_io_width);
 83	if (ret)
 84		reg_io_width = 4;
 85
 86	ret = of_hwspin_lock_get_id(np, 0);
 87	if (ret > 0 || (IS_ENABLED(CONFIG_HWSPINLOCK) && ret == 0)) {
 88		syscon_config.use_hwlock = true;
 89		syscon_config.hwlock_id = ret;
 90		syscon_config.hwlock_mode = HWLOCK_IRQSTATE;
 91	} else if (ret < 0) {
 92		switch (ret) {
 93		case -ENOENT:
 94			/* Ignore missing hwlock, it's optional. */
 95			break;
 96		default:
 97			pr_err("Failed to retrieve valid hwlock: %d\n", ret);
 98			/* fall-through */
 99		case -EPROBE_DEFER:
100			goto err_regmap;
101		}
102	}
103
104	syscon_config.name = of_node_full_name(np);
105	syscon_config.reg_stride = reg_io_width;
106	syscon_config.val_bits = reg_io_width * 8;
107	syscon_config.max_register = resource_size(&res) - reg_io_width;
108	syscon_config.name = of_node_full_name(np);
109
110	regmap = regmap_init_mmio(NULL, base, &syscon_config);
111	if (IS_ERR(regmap)) {
112		pr_err("regmap init failed\n");
113		ret = PTR_ERR(regmap);
114		goto err_regmap;
115	}
116
117	if (check_clk) {
118		clk = of_clk_get(np, 0);
119		if (IS_ERR(clk)) {
120			ret = PTR_ERR(clk);
121			/* clock is optional */
122			if (ret != -ENOENT)
123				goto err_clk;
124		} else {
125			ret = regmap_mmio_attach_clk(regmap, clk);
126			if (ret)
127				goto err_attach;
128		}
129	}
130
131	syscon->regmap = regmap;
132	syscon->np = np;
133
134	spin_lock(&syscon_list_slock);
135	list_add_tail(&syscon->list, &syscon_list);
136	spin_unlock(&syscon_list_slock);
137
138	return syscon;
139
140err_attach:
141	if (!IS_ERR(clk))
142		clk_put(clk);
143err_clk:
144	regmap_exit(regmap);
145err_regmap:
146	iounmap(base);
147err_map:
148	kfree(syscon);
149	return ERR_PTR(ret);
150}
151
152static struct regmap *device_node_get_regmap(struct device_node *np,
153					     bool check_clk)
154{
155	struct syscon *entry, *syscon = NULL;
156
157	spin_lock(&syscon_list_slock);
158
159	list_for_each_entry(entry, &syscon_list, list)
160		if (entry->np == np) {
161			syscon = entry;
162			break;
163		}
164
165	spin_unlock(&syscon_list_slock);
166
167	if (!syscon)
168		syscon = of_syscon_register(np, check_clk);
169
170	if (IS_ERR(syscon))
171		return ERR_CAST(syscon);
172
173	return syscon->regmap;
174}
175
176struct regmap *device_node_to_regmap(struct device_node *np)
177{
178	return device_node_get_regmap(np, false);
179}
180EXPORT_SYMBOL_GPL(device_node_to_regmap);
181
182struct regmap *syscon_node_to_regmap(struct device_node *np)
183{
184	if (!of_device_is_compatible(np, "syscon"))
185		return ERR_PTR(-EINVAL);
186
187	return device_node_get_regmap(np, true);
188}
189EXPORT_SYMBOL_GPL(syscon_node_to_regmap);
190
191struct regmap *syscon_regmap_lookup_by_compatible(const char *s)
192{
193	struct device_node *syscon_np;
194	struct regmap *regmap;
195
196	syscon_np = of_find_compatible_node(NULL, NULL, s);
197	if (!syscon_np)
198		return ERR_PTR(-ENODEV);
199
200	regmap = syscon_node_to_regmap(syscon_np);
201	of_node_put(syscon_np);
202
203	return regmap;
204}
205EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible);
206
207struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np,
208					const char *property)
209{
210	struct device_node *syscon_np;
211	struct regmap *regmap;
212
213	if (property)
214		syscon_np = of_parse_phandle(np, property, 0);
215	else
216		syscon_np = np;
217
218	if (!syscon_np)
219		return ERR_PTR(-ENODEV);
220
221	regmap = syscon_node_to_regmap(syscon_np);
222	of_node_put(syscon_np);
223
224	return regmap;
225}
226EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle);
227
228static int syscon_probe(struct platform_device *pdev)
229{
230	struct device *dev = &pdev->dev;
231	struct syscon_platform_data *pdata = dev_get_platdata(dev);
232	struct syscon *syscon;
233	struct regmap_config syscon_config = syscon_regmap_config;
234	struct resource *res;
235	void __iomem *base;
236
237	syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL);
238	if (!syscon)
239		return -ENOMEM;
240
241	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
242	if (!res)
243		return -ENOENT;
244
245	base = devm_ioremap(dev, res->start, resource_size(res));
246	if (!base)
247		return -ENOMEM;
248
249	syscon_config.max_register = res->end - res->start - 3;
250	if (pdata)
251		syscon_config.name = pdata->label;
252	syscon->regmap = devm_regmap_init_mmio(dev, base, &syscon_config);
253	if (IS_ERR(syscon->regmap)) {
254		dev_err(dev, "regmap init failed\n");
255		return PTR_ERR(syscon->regmap);
256	}
257
258	platform_set_drvdata(pdev, syscon);
259
260	dev_dbg(dev, "regmap %pR registered\n", res);
261
262	return 0;
263}
264
265static const struct platform_device_id syscon_ids[] = {
266	{ "syscon", },
267	{ }
268};
269
270static struct platform_driver syscon_driver = {
271	.driver = {
272		.name = "syscon",
273	},
274	.probe		= syscon_probe,
275	.id_table	= syscon_ids,
276};
277
278static int __init syscon_init(void)
279{
280	return platform_driver_register(&syscon_driver);
281}
282postcore_initcall(syscon_init);