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/cleanup.h>
 12#include <linux/clk.h>
 13#include <linux/err.h>
 14#include <linux/hwspinlock.h>
 15#include <linux/io.h>
 16#include <linux/init.h>
 17#include <linux/list.h>
 18#include <linux/mutex.h>
 19#include <linux/of.h>
 20#include <linux/of_address.h>
 21#include <linux/of_platform.h>
 22#include <linux/platform_data/syscon.h>
 23#include <linux/platform_device.h>
 24#include <linux/regmap.h>
 25#include <linux/reset.h>
 26#include <linux/mfd/syscon.h>
 27#include <linux/slab.h>
 28
 29static struct platform_driver syscon_driver;
 30
 31static DEFINE_MUTEX(syscon_list_lock);
 32static LIST_HEAD(syscon_list);
 33
 34struct syscon {
 35	struct device_node *np;
 36	struct regmap *regmap;
 37	struct reset_control *reset;
 38	struct list_head list;
 39};
 40
 41static const struct regmap_config syscon_regmap_config = {
 42	.reg_bits = 32,
 43	.val_bits = 32,
 44	.reg_stride = 4,
 45};
 46
 47static struct syscon *of_syscon_register(struct device_node *np, bool check_res)
 48{
 49	struct clk *clk;
 50	struct regmap *regmap;
 51	void __iomem *base;
 52	u32 reg_io_width;
 53	int ret;
 54	struct regmap_config syscon_config = syscon_regmap_config;
 55	struct resource res;
 56	struct reset_control *reset;
 57
 58	WARN_ON(!mutex_is_locked(&syscon_list_lock));
 59
 60	struct syscon *syscon __free(kfree) = kzalloc(sizeof(*syscon), GFP_KERNEL);
 61	if (!syscon)
 62		return ERR_PTR(-ENOMEM);
 63
 64	if (of_address_to_resource(np, 0, &res))
 65		return ERR_PTR(-ENOMEM);
 66
 67	base = of_iomap(np, 0);
 68	if (!base)
 69		return ERR_PTR(-ENOMEM);
 70
 71	/* Parse the device's DT node for an endianness specification */
 72	if (of_property_read_bool(np, "big-endian"))
 73		syscon_config.val_format_endian = REGMAP_ENDIAN_BIG;
 74	else if (of_property_read_bool(np, "little-endian"))
 75		syscon_config.val_format_endian = REGMAP_ENDIAN_LITTLE;
 76	else if (of_property_read_bool(np, "native-endian"))
 77		syscon_config.val_format_endian = REGMAP_ENDIAN_NATIVE;
 78
 79	/*
 80	 * search for reg-io-width property in DT. If it is not provided,
 81	 * default to 4 bytes. regmap_init_mmio will return an error if values
 82	 * are invalid so there is no need to check them here.
 83	 */
 84	ret = of_property_read_u32(np, "reg-io-width", &reg_io_width);
 85	if (ret)
 86		reg_io_width = 4;
 87
 88	ret = of_hwspin_lock_get_id(np, 0);
 89	if (ret > 0 || (IS_ENABLED(CONFIG_HWSPINLOCK) && ret == 0)) {
 90		syscon_config.use_hwlock = true;
 91		syscon_config.hwlock_id = ret;
 92		syscon_config.hwlock_mode = HWLOCK_IRQSTATE;
 93	} else if (ret < 0) {
 94		switch (ret) {
 95		case -ENOENT:
 96			/* Ignore missing hwlock, it's optional. */
 97			break;
 98		default:
 99			pr_err("Failed to retrieve valid hwlock: %d\n", ret);
100			fallthrough;
101		case -EPROBE_DEFER:
102			goto err_regmap;
103		}
104	}
105
106	syscon_config.name = kasprintf(GFP_KERNEL, "%pOFn@%pa", np, &res.start);
107	if (!syscon_config.name) {
108		ret = -ENOMEM;
109		goto err_regmap;
110	}
111	syscon_config.reg_stride = reg_io_width;
112	syscon_config.val_bits = reg_io_width * 8;
113	syscon_config.max_register = resource_size(&res) - reg_io_width;
114	if (!syscon_config.max_register)
115		syscon_config.max_register_is_0 = true;
116
117	regmap = regmap_init_mmio(NULL, base, &syscon_config);
118	kfree(syscon_config.name);
119	if (IS_ERR(regmap)) {
120		pr_err("regmap init failed\n");
121		ret = PTR_ERR(regmap);
122		goto err_regmap;
123	}
124
125	if (check_res) {
126		clk = of_clk_get(np, 0);
127		if (IS_ERR(clk)) {
128			ret = PTR_ERR(clk);
129			/* clock is optional */
130			if (ret != -ENOENT)
131				goto err_clk;
132		} else {
133			ret = regmap_mmio_attach_clk(regmap, clk);
134			if (ret)
135				goto err_attach_clk;
136		}
137
138		reset = of_reset_control_get_optional_exclusive(np, NULL);
139		if (IS_ERR(reset)) {
140			ret = PTR_ERR(reset);
141			goto err_attach_clk;
142		}
143
144		ret = reset_control_deassert(reset);
145		if (ret)
146			goto err_reset;
147	}
148
149	syscon->regmap = regmap;
150	syscon->np = np;
151
152	list_add_tail(&syscon->list, &syscon_list);
153
154	return_ptr(syscon);
155
156err_reset:
157	reset_control_put(reset);
158err_attach_clk:
159	if (!IS_ERR(clk))
160		clk_put(clk);
161err_clk:
162	regmap_exit(regmap);
163err_regmap:
164	iounmap(base);
165	return ERR_PTR(ret);
166}
167
168static struct regmap *device_node_get_regmap(struct device_node *np,
169					     bool check_res)
170{
171	struct syscon *entry, *syscon = NULL;
172
173	mutex_lock(&syscon_list_lock);
174
175	list_for_each_entry(entry, &syscon_list, list)
176		if (entry->np == np) {
177			syscon = entry;
178			break;
179		}
180
181	if (!syscon)
182		syscon = of_syscon_register(np, check_res);
183
184	mutex_unlock(&syscon_list_lock);
185
186	if (IS_ERR(syscon))
187		return ERR_CAST(syscon);
188
189	return syscon->regmap;
190}
191
192/**
193 * of_syscon_register_regmap() - Register regmap for specified device node
194 * @np: Device tree node
195 * @regmap: Pointer to regmap object
196 *
197 * Register an externally created regmap object with syscon for the specified
198 * device tree node. This regmap will then be returned to client drivers using
199 * the syscon_regmap_lookup_by_phandle() API.
200 *
201 * Return: 0 on success, negative error code on failure.
202 */
203int of_syscon_register_regmap(struct device_node *np, struct regmap *regmap)
204{
205	struct syscon *entry, *syscon = NULL;
206	int ret;
207
208	if (!np || !regmap)
209		return -EINVAL;
210
211	syscon = kzalloc(sizeof(*syscon), GFP_KERNEL);
212	if (!syscon)
213		return -ENOMEM;
214
215	/* check if syscon entry already exists */
216	mutex_lock(&syscon_list_lock);
217
218	list_for_each_entry(entry, &syscon_list, list)
219		if (entry->np == np) {
220			ret = -EEXIST;
221			goto err_unlock;
222		}
223
224	syscon->regmap = regmap;
225	syscon->np = np;
226
227	/* register the regmap in syscon list */
228	list_add_tail(&syscon->list, &syscon_list);
229	mutex_unlock(&syscon_list_lock);
230
231	return 0;
232
233err_unlock:
234	mutex_unlock(&syscon_list_lock);
235	kfree(syscon);
236	return ret;
237}
238EXPORT_SYMBOL_GPL(of_syscon_register_regmap);
239
240struct regmap *device_node_to_regmap(struct device_node *np)
241{
242	return device_node_get_regmap(np, false);
243}
244EXPORT_SYMBOL_GPL(device_node_to_regmap);
245
246struct regmap *syscon_node_to_regmap(struct device_node *np)
247{
248	if (!of_device_is_compatible(np, "syscon"))
249		return ERR_PTR(-EINVAL);
250
251	return device_node_get_regmap(np, true);
252}
253EXPORT_SYMBOL_GPL(syscon_node_to_regmap);
254
255struct regmap *syscon_regmap_lookup_by_compatible(const char *s)
256{
257	struct device_node *syscon_np;
258	struct regmap *regmap;
259
260	syscon_np = of_find_compatible_node(NULL, NULL, s);
261	if (!syscon_np)
262		return ERR_PTR(-ENODEV);
263
264	regmap = syscon_node_to_regmap(syscon_np);
265	of_node_put(syscon_np);
266
267	return regmap;
268}
269EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible);
270
271struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np,
272					const char *property)
273{
274	struct device_node *syscon_np;
275	struct regmap *regmap;
276
277	if (property)
278		syscon_np = of_parse_phandle(np, property, 0);
279	else
280		syscon_np = np;
281
282	if (!syscon_np)
283		return ERR_PTR(-ENODEV);
284
285	regmap = syscon_node_to_regmap(syscon_np);
286
287	if (property)
288		of_node_put(syscon_np);
289
290	return regmap;
291}
292EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle);
293
294struct regmap *syscon_regmap_lookup_by_phandle_args(struct device_node *np,
295					const char *property,
296					int arg_count,
297					unsigned int *out_args)
298{
299	struct device_node *syscon_np;
300	struct of_phandle_args args;
301	struct regmap *regmap;
302	unsigned int index;
303	int rc;
304
305	rc = of_parse_phandle_with_fixed_args(np, property, arg_count,
306			0, &args);
307	if (rc)
308		return ERR_PTR(rc);
309
310	syscon_np = args.np;
311	if (!syscon_np)
312		return ERR_PTR(-ENODEV);
313
314	regmap = syscon_node_to_regmap(syscon_np);
315	for (index = 0; index < arg_count; index++)
316		out_args[index] = args.args[index];
317	of_node_put(syscon_np);
318
319	return regmap;
320}
321EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_args);
322
323/*
324 * It behaves the same as syscon_regmap_lookup_by_phandle() except where
325 * there is no regmap phandle. In this case, instead of returning -ENODEV,
326 * the function returns NULL.
327 */
328struct regmap *syscon_regmap_lookup_by_phandle_optional(struct device_node *np,
329					const char *property)
330{
331	struct regmap *regmap;
332
333	regmap = syscon_regmap_lookup_by_phandle(np, property);
334	if (IS_ERR(regmap) && PTR_ERR(regmap) == -ENODEV)
335		return NULL;
336
337	return regmap;
338}
339EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_optional);
340
341static int syscon_probe(struct platform_device *pdev)
342{
343	struct device *dev = &pdev->dev;
344	struct syscon_platform_data *pdata = dev_get_platdata(dev);
345	struct syscon *syscon;
346	struct regmap_config syscon_config = syscon_regmap_config;
347	struct resource *res;
348	void __iomem *base;
349
350	syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL);
351	if (!syscon)
352		return -ENOMEM;
353
354	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
355	if (!res)
356		return -ENOENT;
357
358	base = devm_ioremap(dev, res->start, resource_size(res));
359	if (!base)
360		return -ENOMEM;
361
362	syscon_config.max_register = resource_size(res) - 4;
363	if (!syscon_config.max_register)
364		syscon_config.max_register_is_0 = true;
365
366	if (pdata)
367		syscon_config.name = pdata->label;
368	syscon->regmap = devm_regmap_init_mmio(dev, base, &syscon_config);
369	if (IS_ERR(syscon->regmap)) {
370		dev_err(dev, "regmap init failed\n");
371		return PTR_ERR(syscon->regmap);
372	}
373
374	platform_set_drvdata(pdev, syscon);
375
376	dev_dbg(dev, "regmap %pR registered\n", res);
377
378	return 0;
379}
380
381static const struct platform_device_id syscon_ids[] = {
382	{ "syscon", },
383	{ }
384};
385
386static struct platform_driver syscon_driver = {
387	.driver = {
388		.name = "syscon",
389	},
390	.probe		= syscon_probe,
391	.id_table	= syscon_ids,
392};
393
394static int __init syscon_init(void)
395{
396	return platform_driver_register(&syscon_driver);
397}
398postcore_initcall(syscon_init);