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Linux/drivers/rtc/rtc-pcf2127.c

  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 

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