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70e12337 AE |
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> | |
70e12337 AE |
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 */ | |
b5f4184d | 44 | #define ISL12057_REG_RTC_MO_CEN BIT(7) /* Century bit */ |
70e12337 AE |
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 */ | |
5945b288 | 92 | tm->tm_hour = bcd2bin(regs[ISL12057_REG_RTC_HR] & 0x1f); |
70e12337 AE |
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 */ | |
5945b288 | 101 | tm->tm_mon = bcd2bin(regs[ISL12057_REG_RTC_MO] & 0x1f) - 1; /* ditto */ |
70e12337 | 102 | tm->tm_year = bcd2bin(regs[ISL12057_REG_RTC_YR]) + 100; |
b5f4184d AE |
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; | |
70e12337 AE |
107 | } |
108 | ||
109 | static int isl12057_rtc_tm_to_regs(u8 *regs, struct rtc_time *tm) | |
110 | { | |
b5f4184d AE |
111 | u8 century_bit; |
112 | ||
70e12337 AE |
113 | /* |
114 | * The clock has an 8 bit wide bcd-coded register for the year. | |
b5f4184d AE |
115 | * It also has a century bit encoded in MO flag which provides |
116 | * information about overflow of year register from 99 to 00. | |
70e12337 | 117 | * tm_year is an offset from 1900 and we are interested in the |
b5f4184d AE |
118 | * 2000-2199 range, so any value less than 100 or larger than |
119 | * 299 is invalid. | |
70e12337 | 120 | */ |
b5f4184d | 121 | if (tm->tm_year < 100 || tm->tm_year > 299) |
70e12337 AE |
122 | return -EINVAL; |
123 | ||
b5f4184d AE |
124 | century_bit = (tm->tm_year > 199) ? ISL12057_REG_RTC_MO_CEN : 0; |
125 | ||
70e12337 AE |
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); | |
b5f4184d AE |
130 | regs[ISL12057_REG_RTC_MO] = bin2bcd(tm->tm_mon + 1) | century_bit; |
131 | regs[ISL12057_REG_RTC_YR] = bin2bcd(tm->tm_year % 100); | |
70e12337 AE |
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]; | |
10df1e67 | 167 | unsigned int sr; |
70e12337 AE |
168 | int ret; |
169 | ||
170 | mutex_lock(&data->lock); | |
10df1e67 AE |
171 | ret = regmap_read(data->regmap, ISL12057_REG_SR, &sr); |
172 | if (ret) { | |
cf67d0b6 AE |
173 | dev_err(dev, "%s: unable to read oscillator status flag (%d)\n", |
174 | __func__, ret); | |
10df1e67 AE |
175 | goto out; |
176 | } else { | |
177 | if (sr & ISL12057_REG_SR_OSF) { | |
178 | ret = -ENODATA; | |
179 | goto out; | |
180 | } | |
181 | } | |
182 | ||
70e12337 AE |
183 | ret = regmap_bulk_read(data->regmap, ISL12057_REG_RTC_SC, regs, |
184 | ISL12057_RTC_SEC_LEN); | |
10df1e67 | 185 | if (ret) |
cf67d0b6 AE |
186 | dev_err(dev, "%s: unable to read RTC time section (%d)\n", |
187 | __func__, ret); | |
10df1e67 AE |
188 | |
189 | out: | |
70e12337 AE |
190 | mutex_unlock(&data->lock); |
191 | ||
10df1e67 | 192 | if (ret) |
70e12337 | 193 | return ret; |
70e12337 AE |
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); | |
10df1e67 | 213 | if (ret) { |
cf67d0b6 AE |
214 | dev_err(dev, "%s: unable to write RTC time section (%d)\n", |
215 | __func__, ret); | |
10df1e67 AE |
216 | goto out; |
217 | } | |
70e12337 | 218 | |
10df1e67 AE |
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) | |
cf67d0b6 AE |
226 | dev_err(dev, "%s: unable to clear osc. failure bit (%d)\n", |
227 | __func__, ret); | |
10df1e67 AE |
228 | |
229 | out: | |
230 | mutex_unlock(&data->lock); | |
70e12337 AE |
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) { | |
cf67d0b6 AE |
248 | dev_err(dev, "%s: unable to enable oscillator (%d)\n", |
249 | __func__, ret); | |
70e12337 AE |
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) { | |
cf67d0b6 AE |
257 | dev_err(dev, "%s: unable to clear alarm bit (%d)\n", |
258 | __func__, ret); | |
70e12337 AE |
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); | |
cf67d0b6 AE |
292 | dev_err(dev, "%s: regmap allocation failed (%d)\n", |
293 | __func__, ret); | |
70e12337 AE |
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); | |
00b28184 | 314 | return PTR_ERR_OR_ZERO(rtc); |
70e12337 AE |
315 | } |
316 | ||
317 | #ifdef CONFIG_OF | |
8c5bfac0 | 318 | static const struct of_device_id isl12057_dt_match[] = { |
70e12337 AE |
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"); |