xref: /openbmc/linux/drivers/rtc/rtc-pcf2127.c (revision 4f205687)
1 /*
2  * An I2C and SPI driver for the NXP PCF2127/29 RTC
3  * Copyright 2013 Til-Technologies
4  *
5  * Author: Renaud Cerrato <r.cerrato@til-technologies.fr>
6  *
7  * based on the other drivers in this same directory.
8  *
9  * Datasheet: http://cache.nxp.com/documents/data_sheet/PCF2127.pdf
10  *
11  * This program is free software; you can redistribute it and/or modify
12  * it under the terms of the GNU General Public License version 2 as
13  * published by the Free Software Foundation.
14  */
15 
16 #include <linux/i2c.h>
17 #include <linux/spi/spi.h>
18 #include <linux/bcd.h>
19 #include <linux/rtc.h>
20 #include <linux/slab.h>
21 #include <linux/module.h>
22 #include <linux/of.h>
23 #include <linux/regmap.h>
24 
25 #define PCF2127_REG_CTRL1       (0x00)  /* Control Register 1 */
26 #define PCF2127_REG_CTRL2       (0x01)  /* Control Register 2 */
27 
28 #define PCF2127_REG_CTRL3       (0x02)  /* Control Register 3 */
29 #define PCF2127_REG_CTRL3_BLF		BIT(2)
30 
31 #define PCF2127_REG_SC          (0x03)  /* datetime */
32 #define PCF2127_REG_MN          (0x04)
33 #define PCF2127_REG_HR          (0x05)
34 #define PCF2127_REG_DM          (0x06)
35 #define PCF2127_REG_DW          (0x07)
36 #define PCF2127_REG_MO          (0x08)
37 #define PCF2127_REG_YR          (0x09)
38 
39 #define PCF2127_OSF             BIT(7)  /* Oscillator Fail flag */
40 
41 struct pcf2127 {
42 	struct rtc_device *rtc;
43 	struct regmap *regmap;
44 };
45 
46 /*
47  * In the routines that deal directly with the pcf2127 hardware, we use
48  * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
49  */
50 static int pcf2127_rtc_read_time(struct device *dev, struct rtc_time *tm)
51 {
52 	struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
53 	unsigned char buf[10];
54 	int ret;
55 
56 	ret = regmap_bulk_read(pcf2127->regmap, PCF2127_REG_CTRL1, buf,
57 				sizeof(buf));
58 	if (ret) {
59 		dev_err(dev, "%s: read error\n", __func__);
60 		return ret;
61 	}
62 
63 	if (buf[PCF2127_REG_CTRL3] & PCF2127_REG_CTRL3_BLF)
64 		dev_info(dev,
65 			"low voltage detected, check/replace RTC battery.\n");
66 
67 	if (buf[PCF2127_REG_SC] & PCF2127_OSF) {
68 		/*
69 		 * no need clear the flag here,
70 		 * it will be cleared once the new date is saved
71 		 */
72 		dev_warn(dev,
73 			 "oscillator stop detected, date/time is not reliable\n");
74 		return -EINVAL;
75 	}
76 
77 	dev_dbg(dev,
78 		"%s: raw data is cr1=%02x, cr2=%02x, cr3=%02x, "
79 		"sec=%02x, min=%02x, hr=%02x, "
80 		"mday=%02x, wday=%02x, mon=%02x, year=%02x\n",
81 		__func__,
82 		buf[0], buf[1], buf[2],
83 		buf[3], buf[4], buf[5],
84 		buf[6], buf[7], buf[8], buf[9]);
85 
86 
87 	tm->tm_sec = bcd2bin(buf[PCF2127_REG_SC] & 0x7F);
88 	tm->tm_min = bcd2bin(buf[PCF2127_REG_MN] & 0x7F);
89 	tm->tm_hour = bcd2bin(buf[PCF2127_REG_HR] & 0x3F); /* rtc hr 0-23 */
90 	tm->tm_mday = bcd2bin(buf[PCF2127_REG_DM] & 0x3F);
91 	tm->tm_wday = buf[PCF2127_REG_DW] & 0x07;
92 	tm->tm_mon = bcd2bin(buf[PCF2127_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
93 	tm->tm_year = bcd2bin(buf[PCF2127_REG_YR]);
94 	if (tm->tm_year < 70)
95 		tm->tm_year += 100;	/* assume we are in 1970...2069 */
96 
97 	dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
98 		"mday=%d, mon=%d, year=%d, wday=%d\n",
99 		__func__,
100 		tm->tm_sec, tm->tm_min, tm->tm_hour,
101 		tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
102 
103 	return rtc_valid_tm(tm);
104 }
105 
106 static int pcf2127_rtc_set_time(struct device *dev, struct rtc_time *tm)
107 {
108 	struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
109 	unsigned char buf[7];
110 	int i = 0, err;
111 
112 	dev_dbg(dev, "%s: secs=%d, mins=%d, hours=%d, "
113 		"mday=%d, mon=%d, year=%d, wday=%d\n",
114 		__func__,
115 		tm->tm_sec, tm->tm_min, tm->tm_hour,
116 		tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
117 
118 	/* hours, minutes and seconds */
119 	buf[i++] = bin2bcd(tm->tm_sec);	/* this will also clear OSF flag */
120 	buf[i++] = bin2bcd(tm->tm_min);
121 	buf[i++] = bin2bcd(tm->tm_hour);
122 	buf[i++] = bin2bcd(tm->tm_mday);
123 	buf[i++] = tm->tm_wday & 0x07;
124 
125 	/* month, 1 - 12 */
126 	buf[i++] = bin2bcd(tm->tm_mon + 1);
127 
128 	/* year */
129 	buf[i++] = bin2bcd(tm->tm_year % 100);
130 
131 	/* write register's data */
132 	err = regmap_bulk_write(pcf2127->regmap, PCF2127_REG_SC, buf, i);
133 	if (err) {
134 		dev_err(dev,
135 			"%s: err=%d", __func__, err);
136 		return err;
137 	}
138 
139 	return 0;
140 }
141 
142 #ifdef CONFIG_RTC_INTF_DEV
143 static int pcf2127_rtc_ioctl(struct device *dev,
144 				unsigned int cmd, unsigned long arg)
145 {
146 	struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
147 	int touser;
148 	int ret;
149 
150 	switch (cmd) {
151 	case RTC_VL_READ:
152 		ret = regmap_read(pcf2127->regmap, PCF2127_REG_CTRL3, &touser);
153 		if (ret)
154 			return ret;
155 
156 		touser = touser & PCF2127_REG_CTRL3_BLF ? 1 : 0;
157 
158 		if (copy_to_user((void __user *)arg, &touser, sizeof(int)))
159 			return -EFAULT;
160 		return 0;
161 	default:
162 		return -ENOIOCTLCMD;
163 	}
164 }
165 #else
166 #define pcf2127_rtc_ioctl NULL
167 #endif
168 
169 static const struct rtc_class_ops pcf2127_rtc_ops = {
170 	.ioctl		= pcf2127_rtc_ioctl,
171 	.read_time	= pcf2127_rtc_read_time,
172 	.set_time	= pcf2127_rtc_set_time,
173 };
174 
175 static int pcf2127_probe(struct device *dev, struct regmap *regmap,
176 			const char *name)
177 {
178 	struct pcf2127 *pcf2127;
179 
180 	dev_dbg(dev, "%s\n", __func__);
181 
182 	pcf2127 = devm_kzalloc(dev, sizeof(*pcf2127), GFP_KERNEL);
183 	if (!pcf2127)
184 		return -ENOMEM;
185 
186 	pcf2127->regmap = regmap;
187 
188 	dev_set_drvdata(dev, pcf2127);
189 
190 	pcf2127->rtc = devm_rtc_device_register(dev, name, &pcf2127_rtc_ops,
191 						THIS_MODULE);
192 
193 	return PTR_ERR_OR_ZERO(pcf2127->rtc);
194 }
195 
196 #ifdef CONFIG_OF
197 static const struct of_device_id pcf2127_of_match[] = {
198 	{ .compatible = "nxp,pcf2127" },
199 	{ .compatible = "nxp,pcf2129" },
200 	{}
201 };
202 MODULE_DEVICE_TABLE(of, pcf2127_of_match);
203 #endif
204 
205 #if IS_ENABLED(CONFIG_I2C)
206 
207 static int pcf2127_i2c_write(void *context, const void *data, size_t count)
208 {
209 	struct device *dev = context;
210 	struct i2c_client *client = to_i2c_client(dev);
211 	int ret;
212 
213 	ret = i2c_master_send(client, data, count);
214 	if (ret != count)
215 		return ret < 0 ? ret : -EIO;
216 
217 	return 0;
218 }
219 
220 static int pcf2127_i2c_gather_write(void *context,
221 				const void *reg, size_t reg_size,
222 				const void *val, size_t val_size)
223 {
224 	struct device *dev = context;
225 	struct i2c_client *client = to_i2c_client(dev);
226 	int ret;
227 	void *buf;
228 
229 	if (WARN_ON(reg_size != 1))
230 		return -EINVAL;
231 
232 	buf = kmalloc(val_size + 1, GFP_KERNEL);
233 	if (!buf)
234 		return -ENOMEM;
235 
236 	memcpy(buf, reg, 1);
237 	memcpy(buf + 1, val, val_size);
238 
239 	ret = i2c_master_send(client, buf, val_size + 1);
240 	if (ret != val_size + 1)
241 		return ret < 0 ? ret : -EIO;
242 
243 	return 0;
244 }
245 
246 static int pcf2127_i2c_read(void *context, const void *reg, size_t reg_size,
247 				void *val, size_t val_size)
248 {
249 	struct device *dev = context;
250 	struct i2c_client *client = to_i2c_client(dev);
251 	int ret;
252 
253 	if (WARN_ON(reg_size != 1))
254 		return -EINVAL;
255 
256 	ret = i2c_master_send(client, reg, 1);
257 	if (ret != 1)
258 		return ret < 0 ? ret : -EIO;
259 
260 	ret = i2c_master_recv(client, val, val_size);
261 	if (ret != val_size)
262 		return ret < 0 ? ret : -EIO;
263 
264 	return 0;
265 }
266 
267 /*
268  * The reason we need this custom regmap_bus instead of using regmap_init_i2c()
269  * is that the STOP condition is required between set register address and
270  * read register data when reading from registers.
271  */
272 static const struct regmap_bus pcf2127_i2c_regmap = {
273 	.write = pcf2127_i2c_write,
274 	.gather_write = pcf2127_i2c_gather_write,
275 	.read = pcf2127_i2c_read,
276 };
277 
278 static struct i2c_driver pcf2127_i2c_driver;
279 
280 static int pcf2127_i2c_probe(struct i2c_client *client,
281 				const struct i2c_device_id *id)
282 {
283 	struct regmap *regmap;
284 	static const struct regmap_config config = {
285 		.reg_bits = 8,
286 		.val_bits = 8,
287 	};
288 
289 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
290 		return -ENODEV;
291 
292 	regmap = devm_regmap_init(&client->dev, &pcf2127_i2c_regmap,
293 					&client->dev, &config);
294 	if (IS_ERR(regmap)) {
295 		dev_err(&client->dev, "%s: regmap allocation failed: %ld\n",
296 			__func__, PTR_ERR(regmap));
297 		return PTR_ERR(regmap);
298 	}
299 
300 	return pcf2127_probe(&client->dev, regmap,
301 				pcf2127_i2c_driver.driver.name);
302 }
303 
304 static const struct i2c_device_id pcf2127_i2c_id[] = {
305 	{ "pcf2127", 0 },
306 	{ "pcf2129", 0 },
307 	{ }
308 };
309 MODULE_DEVICE_TABLE(i2c, pcf2127_i2c_id);
310 
311 static struct i2c_driver pcf2127_i2c_driver = {
312 	.driver		= {
313 		.name	= "rtc-pcf2127-i2c",
314 		.of_match_table = of_match_ptr(pcf2127_of_match),
315 	},
316 	.probe		= pcf2127_i2c_probe,
317 	.id_table	= pcf2127_i2c_id,
318 };
319 
320 static int pcf2127_i2c_register_driver(void)
321 {
322 	return i2c_add_driver(&pcf2127_i2c_driver);
323 }
324 
325 static void pcf2127_i2c_unregister_driver(void)
326 {
327 	i2c_del_driver(&pcf2127_i2c_driver);
328 }
329 
330 #else
331 
332 static int pcf2127_i2c_register_driver(void)
333 {
334 	return 0;
335 }
336 
337 static void pcf2127_i2c_unregister_driver(void)
338 {
339 }
340 
341 #endif
342 
343 #if IS_ENABLED(CONFIG_SPI_MASTER)
344 
345 static struct spi_driver pcf2127_spi_driver;
346 
347 static int pcf2127_spi_probe(struct spi_device *spi)
348 {
349 	static const struct regmap_config config = {
350 		.reg_bits = 8,
351 		.val_bits = 8,
352 		.read_flag_mask = 0xa0,
353 		.write_flag_mask = 0x20,
354 	};
355 	struct regmap *regmap;
356 
357 	regmap = devm_regmap_init_spi(spi, &config);
358 	if (IS_ERR(regmap)) {
359 		dev_err(&spi->dev, "%s: regmap allocation failed: %ld\n",
360 			__func__, PTR_ERR(regmap));
361 		return PTR_ERR(regmap);
362 	}
363 
364 	return pcf2127_probe(&spi->dev, regmap, pcf2127_spi_driver.driver.name);
365 }
366 
367 static const struct spi_device_id pcf2127_spi_id[] = {
368 	{ "pcf2127", 0 },
369 	{ "pcf2129", 0 },
370 	{ }
371 };
372 MODULE_DEVICE_TABLE(spi, pcf2127_spi_id);
373 
374 static struct spi_driver pcf2127_spi_driver = {
375 	.driver		= {
376 		.name	= "rtc-pcf2127-spi",
377 		.of_match_table = of_match_ptr(pcf2127_of_match),
378 	},
379 	.probe		= pcf2127_spi_probe,
380 	.id_table	= pcf2127_spi_id,
381 };
382 
383 static int pcf2127_spi_register_driver(void)
384 {
385 	return spi_register_driver(&pcf2127_spi_driver);
386 }
387 
388 static void pcf2127_spi_unregister_driver(void)
389 {
390 	spi_unregister_driver(&pcf2127_spi_driver);
391 }
392 
393 #else
394 
395 static int pcf2127_spi_register_driver(void)
396 {
397 	return 0;
398 }
399 
400 static void pcf2127_spi_unregister_driver(void)
401 {
402 }
403 
404 #endif
405 
406 static int __init pcf2127_init(void)
407 {
408 	int ret;
409 
410 	ret = pcf2127_i2c_register_driver();
411 	if (ret) {
412 		pr_err("Failed to register pcf2127 i2c driver: %d\n", ret);
413 		return ret;
414 	}
415 
416 	ret = pcf2127_spi_register_driver();
417 	if (ret) {
418 		pr_err("Failed to register pcf2127 spi driver: %d\n", ret);
419 		pcf2127_i2c_unregister_driver();
420 	}
421 
422 	return ret;
423 }
424 module_init(pcf2127_init)
425 
426 static void __exit pcf2127_exit(void)
427 {
428 	pcf2127_spi_unregister_driver();
429 	pcf2127_i2c_unregister_driver();
430 }
431 module_exit(pcf2127_exit)
432 
433 MODULE_AUTHOR("Renaud Cerrato <r.cerrato@til-technologies.fr>");
434 MODULE_DESCRIPTION("NXP PCF2127/29 RTC driver");
435 MODULE_LICENSE("GPL v2");
436