Version:  2.0.40 2.2.26 2.4.37 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19

Linux/drivers/rtc/rtc-isl12057.c

  1 /*
  2  * rtc-isl12057 - Driver for Intersil ISL12057 I2C Real Time Clock
  3  *
  4  * Copyright (C) 2013, Arnaud EBALARD <arno@natisbad.org>
  5  *
  6  * This work is largely based on Intersil ISL1208 driver developed by
  7  * Hebert Valerio Riedel <hvr@gnu.org>.
  8  *
  9  * Detailed datasheet on which this development is based is available here:
 10  *
 11  *  http://natisbad.org/NAS2/refs/ISL12057.pdf
 12  *
 13  * This program is free software; you can redistribute it and/or modify
 14  * it under the terms of the GNU General Public License as published by
 15  * the Free Software Foundation; either version 2 of the License, or
 16  * (at your option) any later version.
 17  *
 18  * This program is distributed in the hope that it will be useful,
 19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 21  * GNU General Public License for more details.
 22  */
 23 
 24 #include <linux/module.h>
 25 #include <linux/mutex.h>
 26 #include <linux/rtc.h>
 27 #include <linux/i2c.h>
 28 #include <linux/bcd.h>
 29 #include <linux/of.h>
 30 #include <linux/of_device.h>
 31 #include <linux/regmap.h>
 32 
 33 #define DRV_NAME "rtc-isl12057"
 34 
 35 /* RTC section */
 36 #define ISL12057_REG_RTC_SC     0x00    /* Seconds */
 37 #define ISL12057_REG_RTC_MN     0x01    /* Minutes */
 38 #define ISL12057_REG_RTC_HR     0x02    /* Hours */
 39 #define ISL12057_REG_RTC_HR_PM  BIT(5)  /* AM/PM bit in 12h format */
 40 #define ISL12057_REG_RTC_HR_MIL BIT(6)  /* 24h/12h format */
 41 #define ISL12057_REG_RTC_DW     0x03    /* Day of the Week */
 42 #define ISL12057_REG_RTC_DT     0x04    /* Date */
 43 #define ISL12057_REG_RTC_MO     0x05    /* Month */
 44 #define ISL12057_REG_RTC_MO_CEN BIT(7)  /* Century bit */
 45 #define ISL12057_REG_RTC_YR     0x06    /* Year */
 46 #define ISL12057_RTC_SEC_LEN    7
 47 
 48 /* Alarm 1 section */
 49 #define ISL12057_REG_A1_SC      0x07    /* Alarm 1 Seconds */
 50 #define ISL12057_REG_A1_MN      0x08    /* Alarm 1 Minutes */
 51 #define ISL12057_REG_A1_HR      0x09    /* Alarm 1 Hours */
 52 #define ISL12057_REG_A1_HR_PM   BIT(5)  /* AM/PM bit in 12h format */
 53 #define ISL12057_REG_A1_HR_MIL  BIT(6)  /* 24h/12h format */
 54 #define ISL12057_REG_A1_DWDT    0x0A    /* Alarm 1 Date / Day of the week */
 55 #define ISL12057_REG_A1_DWDT_B  BIT(6)  /* DW / DT selection bit */
 56 #define ISL12057_A1_SEC_LEN     4
 57 
 58 /* Alarm 2 section */
 59 #define ISL12057_REG_A2_MN      0x0B    /* Alarm 2 Minutes */
 60 #define ISL12057_REG_A2_HR      0x0C    /* Alarm 2 Hours */
 61 #define ISL12057_REG_A2_DWDT    0x0D    /* Alarm 2 Date / Day of the week */
 62 #define ISL12057_A2_SEC_LEN     3
 63 
 64 /* Control/Status registers */
 65 #define ISL12057_REG_INT        0x0E
 66 #define ISL12057_REG_INT_A1IE   BIT(0)  /* Alarm 1 interrupt enable bit */
 67 #define ISL12057_REG_INT_A2IE   BIT(1)  /* Alarm 2 interrupt enable bit */
 68 #define ISL12057_REG_INT_INTCN  BIT(2)  /* Interrupt control enable bit */
 69 #define ISL12057_REG_INT_RS1    BIT(3)  /* Freq out control bit 1 */
 70 #define ISL12057_REG_INT_RS2    BIT(4)  /* Freq out control bit 2 */
 71 #define ISL12057_REG_INT_EOSC   BIT(7)  /* Oscillator enable bit */
 72 
 73 #define ISL12057_REG_SR         0x0F
 74 #define ISL12057_REG_SR_A1F     BIT(0)  /* Alarm 1 interrupt bit */
 75 #define ISL12057_REG_SR_A2F     BIT(1)  /* Alarm 2 interrupt bit */
 76 #define ISL12057_REG_SR_OSF     BIT(7)  /* Oscillator failure bit */
 77 
 78 /* Register memory map length */
 79 #define ISL12057_MEM_MAP_LEN    0x10
 80 
 81 struct isl12057_rtc_data {
 82         struct regmap *regmap;
 83         struct mutex lock;
 84 };
 85 
 86 static void isl12057_rtc_regs_to_tm(struct rtc_time *tm, u8 *regs)
 87 {
 88         tm->tm_sec = bcd2bin(regs[ISL12057_REG_RTC_SC]);
 89         tm->tm_min = bcd2bin(regs[ISL12057_REG_RTC_MN]);
 90 
 91         if (regs[ISL12057_REG_RTC_HR] & ISL12057_REG_RTC_HR_MIL) { /* AM/PM */
 92                 tm->tm_hour = bcd2bin(regs[ISL12057_REG_RTC_HR] & 0x1f);
 93                 if (regs[ISL12057_REG_RTC_HR] & ISL12057_REG_RTC_HR_PM)
 94                         tm->tm_hour += 12;
 95         } else {                                            /* 24 hour mode */
 96                 tm->tm_hour = bcd2bin(regs[ISL12057_REG_RTC_HR] & 0x3f);
 97         }
 98 
 99         tm->tm_mday = bcd2bin(regs[ISL12057_REG_RTC_DT]);
100         tm->tm_wday = bcd2bin(regs[ISL12057_REG_RTC_DW]) - 1; /* starts at 1 */
101         tm->tm_mon  = bcd2bin(regs[ISL12057_REG_RTC_MO] & 0x1f) - 1; /* ditto */
102         tm->tm_year = bcd2bin(regs[ISL12057_REG_RTC_YR]) + 100;
103 
104         /* Check if years register has overflown from 99 to 00 */
105         if (regs[ISL12057_REG_RTC_MO] & ISL12057_REG_RTC_MO_CEN)
106                 tm->tm_year += 100;
107 }
108 
109 static int isl12057_rtc_tm_to_regs(u8 *regs, struct rtc_time *tm)
110 {
111         u8 century_bit;
112 
113         /*
114          * The clock has an 8 bit wide bcd-coded register for the year.
115          * It also has a century bit encoded in MO flag which provides
116          * information about overflow of year register from 99 to 00.
117          * tm_year is an offset from 1900 and we are interested in the
118          * 2000-2199 range, so any value less than 100 or larger than
119          * 299 is invalid.
120          */
121         if (tm->tm_year < 100 || tm->tm_year > 299)
122                 return -EINVAL;
123 
124         century_bit = (tm->tm_year > 199) ? ISL12057_REG_RTC_MO_CEN : 0;
125 
126         regs[ISL12057_REG_RTC_SC] = bin2bcd(tm->tm_sec);
127         regs[ISL12057_REG_RTC_MN] = bin2bcd(tm->tm_min);
128         regs[ISL12057_REG_RTC_HR] = bin2bcd(tm->tm_hour); /* 24-hour format */
129         regs[ISL12057_REG_RTC_DT] = bin2bcd(tm->tm_mday);
130         regs[ISL12057_REG_RTC_MO] = bin2bcd(tm->tm_mon + 1) | century_bit;
131         regs[ISL12057_REG_RTC_YR] = bin2bcd(tm->tm_year % 100);
132         regs[ISL12057_REG_RTC_DW] = bin2bcd(tm->tm_wday + 1);
133 
134         return 0;
135 }
136 
137 /*
138  * Try and match register bits w/ fixed null values to see whether we
139  * are dealing with an ISL12057. Note: this function is called early
140  * during init and hence does need mutex protection.
141  */
142 static int isl12057_i2c_validate_chip(struct regmap *regmap)
143 {
144         u8 regs[ISL12057_MEM_MAP_LEN];
145         static const u8 mask[ISL12057_MEM_MAP_LEN] = { 0x80, 0x80, 0x80, 0xf8,
146                                                        0xc0, 0x60, 0x00, 0x00,
147                                                        0x00, 0x00, 0x00, 0x00,
148                                                        0x00, 0x00, 0x60, 0x7c };
149         int ret, i;
150 
151         ret = regmap_bulk_read(regmap, 0, regs, ISL12057_MEM_MAP_LEN);
152         if (ret)
153                 return ret;
154 
155         for (i = 0; i < ISL12057_MEM_MAP_LEN; ++i) {
156                 if (regs[i] & mask[i])  /* check if bits are cleared */
157                         return -ENODEV;
158         }
159 
160         return 0;
161 }
162 
163 static int isl12057_rtc_read_time(struct device *dev, struct rtc_time *tm)
164 {
165         struct isl12057_rtc_data *data = dev_get_drvdata(dev);
166         u8 regs[ISL12057_RTC_SEC_LEN];
167         unsigned int sr;
168         int ret;
169 
170         mutex_lock(&data->lock);
171         ret = regmap_read(data->regmap, ISL12057_REG_SR, &sr);
172         if (ret) {
173                 dev_err(dev, "%s: unable to read oscillator status flag (%d)\n",
174                         __func__, ret);
175                 goto out;
176         } else {
177                 if (sr & ISL12057_REG_SR_OSF) {
178                         ret = -ENODATA;
179                         goto out;
180                 }
181         }
182 
183         ret = regmap_bulk_read(data->regmap, ISL12057_REG_RTC_SC, regs,
184                                ISL12057_RTC_SEC_LEN);
185         if (ret)
186                 dev_err(dev, "%s: unable to read RTC time section (%d)\n",
187                         __func__, ret);
188 
189 out:
190         mutex_unlock(&data->lock);
191 
192         if (ret)
193                 return ret;
194 
195         isl12057_rtc_regs_to_tm(tm, regs);
196 
197         return rtc_valid_tm(tm);
198 }
199 
200 static int isl12057_rtc_set_time(struct device *dev, struct rtc_time *tm)
201 {
202         struct isl12057_rtc_data *data = dev_get_drvdata(dev);
203         u8 regs[ISL12057_RTC_SEC_LEN];
204         int ret;
205 
206         ret = isl12057_rtc_tm_to_regs(regs, tm);
207         if (ret)
208                 return ret;
209 
210         mutex_lock(&data->lock);
211         ret = regmap_bulk_write(data->regmap, ISL12057_REG_RTC_SC, regs,
212                                 ISL12057_RTC_SEC_LEN);
213         if (ret) {
214                 dev_err(dev, "%s: unable to write RTC time section (%d)\n",
215                         __func__, ret);
216                 goto out;
217         }
218 
219         /*
220          * Now that RTC time has been updated, let's clear oscillator
221          * failure flag, if needed.
222          */
223         ret = regmap_update_bits(data->regmap, ISL12057_REG_SR,
224                                  ISL12057_REG_SR_OSF, 0);
225         if (ret < 0)
226                 dev_err(dev, "%s: unable to clear osc. failure bit (%d)\n",
227                         __func__, ret);
228 
229 out:
230         mutex_unlock(&data->lock);
231 
232         return ret;
233 }
234 
235 /*
236  * Check current RTC status and enable/disable what needs to be. Return 0 if
237  * everything went ok and a negative value upon error. Note: this function
238  * is called early during init and hence does need mutex protection.
239  */
240 static int isl12057_check_rtc_status(struct device *dev, struct regmap *regmap)
241 {
242         int ret;
243 
244         /* Enable oscillator if not already running */
245         ret = regmap_update_bits(regmap, ISL12057_REG_INT,
246                                  ISL12057_REG_INT_EOSC, 0);
247         if (ret < 0) {
248                 dev_err(dev, "%s: unable to enable oscillator (%d)\n",
249                         __func__, ret);
250                 return ret;
251         }
252 
253         /* Clear alarm bit if needed */
254         ret = regmap_update_bits(regmap, ISL12057_REG_SR,
255                                  ISL12057_REG_SR_A1F, 0);
256         if (ret < 0) {
257                 dev_err(dev, "%s: unable to clear alarm bit (%d)\n",
258                         __func__, ret);
259                 return ret;
260         }
261 
262         return 0;
263 }
264 
265 static const struct rtc_class_ops rtc_ops = {
266         .read_time = isl12057_rtc_read_time,
267         .set_time = isl12057_rtc_set_time,
268 };
269 
270 static struct regmap_config isl12057_rtc_regmap_config = {
271         .reg_bits = 8,
272         .val_bits = 8,
273 };
274 
275 static int isl12057_probe(struct i2c_client *client,
276                           const struct i2c_device_id *id)
277 {
278         struct device *dev = &client->dev;
279         struct isl12057_rtc_data *data;
280         struct rtc_device *rtc;
281         struct regmap *regmap;
282         int ret;
283 
284         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
285                                      I2C_FUNC_SMBUS_BYTE_DATA |
286                                      I2C_FUNC_SMBUS_I2C_BLOCK))
287                 return -ENODEV;
288 
289         regmap = devm_regmap_init_i2c(client, &isl12057_rtc_regmap_config);
290         if (IS_ERR(regmap)) {
291                 ret = PTR_ERR(regmap);
292                 dev_err(dev, "%s: regmap allocation failed (%d)\n",
293                         __func__, ret);
294                 return ret;
295         }
296 
297         ret = isl12057_i2c_validate_chip(regmap);
298         if (ret)
299                 return ret;
300 
301         ret = isl12057_check_rtc_status(dev, regmap);
302         if (ret)
303                 return ret;
304 
305         data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
306         if (!data)
307                 return -ENOMEM;
308 
309         mutex_init(&data->lock);
310         data->regmap = regmap;
311         dev_set_drvdata(dev, data);
312 
313         rtc = devm_rtc_device_register(dev, DRV_NAME, &rtc_ops, THIS_MODULE);
314         return PTR_ERR_OR_ZERO(rtc);
315 }
316 
317 #ifdef CONFIG_OF
318 static const struct of_device_id isl12057_dt_match[] = {
319         { .compatible = "isl,isl12057" },
320         { },
321 };
322 #endif
323 
324 static const struct i2c_device_id isl12057_id[] = {
325         { "isl12057", 0 },
326         { }
327 };
328 MODULE_DEVICE_TABLE(i2c, isl12057_id);
329 
330 static struct i2c_driver isl12057_driver = {
331         .driver = {
332                 .name = DRV_NAME,
333                 .owner = THIS_MODULE,
334                 .of_match_table = of_match_ptr(isl12057_dt_match),
335         },
336         .probe    = isl12057_probe,
337         .id_table = isl12057_id,
338 };
339 module_i2c_driver(isl12057_driver);
340 
341 MODULE_AUTHOR("Arnaud EBALARD <arno@natisbad.org>");
342 MODULE_DESCRIPTION("Intersil ISL12057 RTC driver");
343 MODULE_LICENSE("GPL");
344 

This page was automatically generated by LXR 0.3.1 (source).  •  Linux is a registered trademark of Linus Torvalds  •  Contact us