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			fallthrough;
 99		case -EPROBE_DEFER:
100			goto err_regmap;
101		}
102	}
103
104	syscon_config.name = kasprintf(GFP_KERNEL, "%pOFn@%llx", np,
105				       (u64)res.start);
106	syscon_config.reg_stride = reg_io_width;
107	syscon_config.val_bits = reg_io_width * 8;
108	syscon_config.max_register = resource_size(&res) - reg_io_width;
109
110	regmap = regmap_init_mmio(NULL, base, &syscon_config);
111	kfree(syscon_config.name);
112	if (IS_ERR(regmap)) {
113		pr_err("regmap init failed\n");
114		ret = PTR_ERR(regmap);
115		goto err_regmap;
116	}
117
118	if (check_clk) {
119		clk = of_clk_get(np, 0);
120		if (IS_ERR(clk)) {
121			ret = PTR_ERR(clk);
122			/* clock is optional */
123			if (ret != -ENOENT)
124				goto err_clk;
125		} else {
126			ret = regmap_mmio_attach_clk(regmap, clk);
127			if (ret)
128				goto err_attach;
129		}
130	}
131
132	syscon->regmap = regmap;
133	syscon->np = np;
134
135	spin_lock(&syscon_list_slock);
136	list_add_tail(&syscon->list, &syscon_list);
137	spin_unlock(&syscon_list_slock);
138
139	return syscon;
140
141err_attach:
142	if (!IS_ERR(clk))
143		clk_put(clk);
144err_clk:
145	regmap_exit(regmap);
146err_regmap:
147	iounmap(base);
148err_map:
149	kfree(syscon);
150	return ERR_PTR(ret);
151}
152
153static struct regmap *device_node_get_regmap(struct device_node *np,
154					     bool check_clk)
155{
156	struct syscon *entry, *syscon = NULL;
157
158	spin_lock(&syscon_list_slock);
159
160	list_for_each_entry(entry, &syscon_list, list)
161		if (entry->np == np) {
162			syscon = entry;
163			break;
164		}
165
166	spin_unlock(&syscon_list_slock);
167
168	if (!syscon)
169		syscon = of_syscon_register(np, check_clk);
170
171	if (IS_ERR(syscon))
172		return ERR_CAST(syscon);
173
174	return syscon->regmap;
175}
176
177struct regmap *device_node_to_regmap(struct device_node *np)
178{
179	return device_node_get_regmap(np, false);
180}
181EXPORT_SYMBOL_GPL(device_node_to_regmap);
182
183struct regmap *syscon_node_to_regmap(struct device_node *np)
184{
185	if (!of_device_is_compatible(np, "syscon"))
186		return ERR_PTR(-EINVAL);
187
188	return device_node_get_regmap(np, true);
189}
190EXPORT_SYMBOL_GPL(syscon_node_to_regmap);
191
192struct regmap *syscon_regmap_lookup_by_compatible(const char *s)
193{
194	struct device_node *syscon_np;
195	struct regmap *regmap;
196
197	syscon_np = of_find_compatible_node(NULL, NULL, s);
198	if (!syscon_np)
199		return ERR_PTR(-ENODEV);
200
201	regmap = syscon_node_to_regmap(syscon_np);
202	of_node_put(syscon_np);
203
204	return regmap;
205}
206EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible);
207
208struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np,
209					const char *property)
210{
211	struct device_node *syscon_np;
212	struct regmap *regmap;
213
214	if (property)
215		syscon_np = of_parse_phandle(np, property, 0);
216	else
217		syscon_np = np;
218
219	if (!syscon_np)
220		return ERR_PTR(-ENODEV);
221
222	regmap = syscon_node_to_regmap(syscon_np);
223	of_node_put(syscon_np);
224
225	return regmap;
226}
227EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle);
228
229struct regmap *syscon_regmap_lookup_by_phandle_args(struct device_node *np,
230					const char *property,
231					int arg_count,
232					unsigned int *out_args)
233{
234	struct device_node *syscon_np;
235	struct of_phandle_args args;
236	struct regmap *regmap;
237	unsigned int index;
238	int rc;
239
240	rc = of_parse_phandle_with_fixed_args(np, property, arg_count,
241			0, &args);
242	if (rc)
243		return ERR_PTR(rc);
244
245	syscon_np = args.np;
246	if (!syscon_np)
247		return ERR_PTR(-ENODEV);
248
249	regmap = syscon_node_to_regmap(syscon_np);
250	for (index = 0; index < arg_count; index++)
251		out_args[index] = args.args[index];
252	of_node_put(syscon_np);
253
254	return regmap;
255}
256EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_args);
257
258static int syscon_probe(struct platform_device *pdev)
259{
260	struct device *dev = &pdev->dev;
261	struct syscon_platform_data *pdata = dev_get_platdata(dev);
262	struct syscon *syscon;
263	struct regmap_config syscon_config = syscon_regmap_config;
264	struct resource *res;
265	void __iomem *base;
266
267	syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL);
268	if (!syscon)
269		return -ENOMEM;
270
271	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
272	if (!res)
273		return -ENOENT;
274
275	base = devm_ioremap(dev, res->start, resource_size(res));
276	if (!base)
277		return -ENOMEM;
278
279	syscon_config.max_register = resource_size(res) - 4;
280	if (pdata)
281		syscon_config.name = pdata->label;
282	syscon->regmap = devm_regmap_init_mmio(dev, base, &syscon_config);
283	if (IS_ERR(syscon->regmap)) {
284		dev_err(dev, "regmap init failed\n");
285		return PTR_ERR(syscon->regmap);
286	}
287
288	platform_set_drvdata(pdev, syscon);
289
290	dev_dbg(dev, "regmap %pR registered\n", res);
291
292	return 0;
293}
294
295static const struct platform_device_id syscon_ids[] = {
296	{ "syscon", },
297	{ }
298};
299
300static struct platform_driver syscon_driver = {
301	.driver = {
302		.name = "syscon",
303	},
304	.probe		= syscon_probe,
305	.id_table	= syscon_ids,
306};
307
308static int __init syscon_init(void)
309{
310	return platform_driver_register(&syscon_driver);
311}
312postcore_initcall(syscon_init);