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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 */ | |
44 | #define ISL12057_REG_RTC_YR 0x06 /* Year */ | |
45 | #define ISL12057_RTC_SEC_LEN 7 | |
46 | ||
47 | /* Alarm 1 section */ | |
48 | #define ISL12057_REG_A1_SC 0x07 /* Alarm 1 Seconds */ | |
49 | #define ISL12057_REG_A1_MN 0x08 /* Alarm 1 Minutes */ | |
50 | #define ISL12057_REG_A1_HR 0x09 /* Alarm 1 Hours */ | |
51 | #define ISL12057_REG_A1_HR_PM BIT(5) /* AM/PM bit in 12h format */ | |
52 | #define ISL12057_REG_A1_HR_MIL BIT(6) /* 24h/12h format */ | |
53 | #define ISL12057_REG_A1_DWDT 0x0A /* Alarm 1 Date / Day of the week */ | |
54 | #define ISL12057_REG_A1_DWDT_B BIT(6) /* DW / DT selection bit */ | |
55 | #define ISL12057_A1_SEC_LEN 4 | |
56 | ||
57 | /* Alarm 2 section */ | |
58 | #define ISL12057_REG_A2_MN 0x0B /* Alarm 2 Minutes */ | |
59 | #define ISL12057_REG_A2_HR 0x0C /* Alarm 2 Hours */ | |
60 | #define ISL12057_REG_A2_DWDT 0x0D /* Alarm 2 Date / Day of the week */ | |
61 | #define ISL12057_A2_SEC_LEN 3 | |
62 | ||
63 | /* Control/Status registers */ | |
64 | #define ISL12057_REG_INT 0x0E | |
65 | #define ISL12057_REG_INT_A1IE BIT(0) /* Alarm 1 interrupt enable bit */ | |
66 | #define ISL12057_REG_INT_A2IE BIT(1) /* Alarm 2 interrupt enable bit */ | |
67 | #define ISL12057_REG_INT_INTCN BIT(2) /* Interrupt control enable bit */ | |
68 | #define ISL12057_REG_INT_RS1 BIT(3) /* Freq out control bit 1 */ | |
69 | #define ISL12057_REG_INT_RS2 BIT(4) /* Freq out control bit 2 */ | |
70 | #define ISL12057_REG_INT_EOSC BIT(7) /* Oscillator enable bit */ | |
71 | ||
72 | #define ISL12057_REG_SR 0x0F | |
73 | #define ISL12057_REG_SR_A1F BIT(0) /* Alarm 1 interrupt bit */ | |
74 | #define ISL12057_REG_SR_A2F BIT(1) /* Alarm 2 interrupt bit */ | |
75 | #define ISL12057_REG_SR_OSF BIT(7) /* Oscillator failure bit */ | |
76 | ||
77 | /* Register memory map length */ | |
78 | #define ISL12057_MEM_MAP_LEN 0x10 | |
79 | ||
80 | struct isl12057_rtc_data { | |
81 | struct regmap *regmap; | |
82 | struct mutex lock; | |
83 | }; | |
84 | ||
85 | static void isl12057_rtc_regs_to_tm(struct rtc_time *tm, u8 *regs) | |
86 | { | |
87 | tm->tm_sec = bcd2bin(regs[ISL12057_REG_RTC_SC]); | |
88 | tm->tm_min = bcd2bin(regs[ISL12057_REG_RTC_MN]); | |
89 | ||
90 | if (regs[ISL12057_REG_RTC_HR] & ISL12057_REG_RTC_HR_MIL) { /* AM/PM */ | |
91 | tm->tm_hour = bcd2bin(regs[ISL12057_REG_RTC_HR] & 0x0f); | |
92 | if (regs[ISL12057_REG_RTC_HR] & ISL12057_REG_RTC_HR_PM) | |
93 | tm->tm_hour += 12; | |
94 | } else { /* 24 hour mode */ | |
95 | tm->tm_hour = bcd2bin(regs[ISL12057_REG_RTC_HR] & 0x3f); | |
96 | } | |
97 | ||
98 | tm->tm_mday = bcd2bin(regs[ISL12057_REG_RTC_DT]); | |
99 | tm->tm_wday = bcd2bin(regs[ISL12057_REG_RTC_DW]) - 1; /* starts at 1 */ | |
100 | tm->tm_mon = bcd2bin(regs[ISL12057_REG_RTC_MO]) - 1; /* starts at 1 */ | |
101 | tm->tm_year = bcd2bin(regs[ISL12057_REG_RTC_YR]) + 100; | |
102 | } | |
103 | ||
104 | static int isl12057_rtc_tm_to_regs(u8 *regs, struct rtc_time *tm) | |
105 | { | |
106 | /* | |
107 | * The clock has an 8 bit wide bcd-coded register for the year. | |
108 | * tm_year is an offset from 1900 and we are interested in the | |
109 | * 2000-2099 range, so any value less than 100 is invalid. | |
110 | */ | |
111 | if (tm->tm_year < 100) | |
112 | return -EINVAL; | |
113 | ||
114 | regs[ISL12057_REG_RTC_SC] = bin2bcd(tm->tm_sec); | |
115 | regs[ISL12057_REG_RTC_MN] = bin2bcd(tm->tm_min); | |
116 | regs[ISL12057_REG_RTC_HR] = bin2bcd(tm->tm_hour); /* 24-hour format */ | |
117 | regs[ISL12057_REG_RTC_DT] = bin2bcd(tm->tm_mday); | |
118 | regs[ISL12057_REG_RTC_MO] = bin2bcd(tm->tm_mon + 1); | |
119 | regs[ISL12057_REG_RTC_YR] = bin2bcd(tm->tm_year - 100); | |
120 | regs[ISL12057_REG_RTC_DW] = bin2bcd(tm->tm_wday + 1); | |
121 | ||
122 | return 0; | |
123 | } | |
124 | ||
125 | /* | |
126 | * Try and match register bits w/ fixed null values to see whether we | |
127 | * are dealing with an ISL12057. Note: this function is called early | |
128 | * during init and hence does need mutex protection. | |
129 | */ | |
130 | static int isl12057_i2c_validate_chip(struct regmap *regmap) | |
131 | { | |
132 | u8 regs[ISL12057_MEM_MAP_LEN]; | |
133 | static const u8 mask[ISL12057_MEM_MAP_LEN] = { 0x80, 0x80, 0x80, 0xf8, | |
134 | 0xc0, 0x60, 0x00, 0x00, | |
135 | 0x00, 0x00, 0x00, 0x00, | |
136 | 0x00, 0x00, 0x60, 0x7c }; | |
137 | int ret, i; | |
138 | ||
139 | ret = regmap_bulk_read(regmap, 0, regs, ISL12057_MEM_MAP_LEN); | |
140 | if (ret) | |
141 | return ret; | |
142 | ||
143 | for (i = 0; i < ISL12057_MEM_MAP_LEN; ++i) { | |
144 | if (regs[i] & mask[i]) /* check if bits are cleared */ | |
145 | return -ENODEV; | |
146 | } | |
147 | ||
148 | return 0; | |
149 | } | |
150 | ||
151 | static int isl12057_rtc_read_time(struct device *dev, struct rtc_time *tm) | |
152 | { | |
153 | struct isl12057_rtc_data *data = dev_get_drvdata(dev); | |
154 | u8 regs[ISL12057_RTC_SEC_LEN]; | |
155 | int ret; | |
156 | ||
157 | mutex_lock(&data->lock); | |
158 | ret = regmap_bulk_read(data->regmap, ISL12057_REG_RTC_SC, regs, | |
159 | ISL12057_RTC_SEC_LEN); | |
160 | mutex_unlock(&data->lock); | |
161 | ||
162 | if (ret) { | |
163 | dev_err(dev, "%s: RTC read failed\n", __func__); | |
164 | return ret; | |
165 | } | |
166 | ||
167 | isl12057_rtc_regs_to_tm(tm, regs); | |
168 | ||
169 | return rtc_valid_tm(tm); | |
170 | } | |
171 | ||
172 | static int isl12057_rtc_set_time(struct device *dev, struct rtc_time *tm) | |
173 | { | |
174 | struct isl12057_rtc_data *data = dev_get_drvdata(dev); | |
175 | u8 regs[ISL12057_RTC_SEC_LEN]; | |
176 | int ret; | |
177 | ||
178 | ret = isl12057_rtc_tm_to_regs(regs, tm); | |
179 | if (ret) | |
180 | return ret; | |
181 | ||
182 | mutex_lock(&data->lock); | |
183 | ret = regmap_bulk_write(data->regmap, ISL12057_REG_RTC_SC, regs, | |
184 | ISL12057_RTC_SEC_LEN); | |
185 | mutex_unlock(&data->lock); | |
186 | ||
187 | if (ret) | |
188 | dev_err(dev, "%s: RTC write failed\n", __func__); | |
189 | ||
190 | return ret; | |
191 | } | |
192 | ||
193 | /* | |
194 | * Check current RTC status and enable/disable what needs to be. Return 0 if | |
195 | * everything went ok and a negative value upon error. Note: this function | |
196 | * is called early during init and hence does need mutex protection. | |
197 | */ | |
198 | static int isl12057_check_rtc_status(struct device *dev, struct regmap *regmap) | |
199 | { | |
200 | int ret; | |
201 | ||
202 | /* Enable oscillator if not already running */ | |
203 | ret = regmap_update_bits(regmap, ISL12057_REG_INT, | |
204 | ISL12057_REG_INT_EOSC, 0); | |
205 | if (ret < 0) { | |
206 | dev_err(dev, "Unable to enable oscillator\n"); | |
207 | return ret; | |
208 | } | |
209 | ||
210 | /* Clear oscillator failure bit if needed */ | |
211 | ret = regmap_update_bits(regmap, ISL12057_REG_SR, | |
212 | ISL12057_REG_SR_OSF, 0); | |
213 | if (ret < 0) { | |
214 | dev_err(dev, "Unable to clear oscillator failure bit\n"); | |
215 | return ret; | |
216 | } | |
217 | ||
218 | /* Clear alarm bit if needed */ | |
219 | ret = regmap_update_bits(regmap, ISL12057_REG_SR, | |
220 | ISL12057_REG_SR_A1F, 0); | |
221 | if (ret < 0) { | |
222 | dev_err(dev, "Unable to clear alarm bit\n"); | |
223 | return ret; | |
224 | } | |
225 | ||
226 | return 0; | |
227 | } | |
228 | ||
229 | static const struct rtc_class_ops rtc_ops = { | |
230 | .read_time = isl12057_rtc_read_time, | |
231 | .set_time = isl12057_rtc_set_time, | |
232 | }; | |
233 | ||
234 | static struct regmap_config isl12057_rtc_regmap_config = { | |
235 | .reg_bits = 8, | |
236 | .val_bits = 8, | |
237 | }; | |
238 | ||
239 | static int isl12057_probe(struct i2c_client *client, | |
240 | const struct i2c_device_id *id) | |
241 | { | |
242 | struct device *dev = &client->dev; | |
243 | struct isl12057_rtc_data *data; | |
244 | struct rtc_device *rtc; | |
245 | struct regmap *regmap; | |
246 | int ret; | |
247 | ||
248 | if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C | | |
249 | I2C_FUNC_SMBUS_BYTE_DATA | | |
250 | I2C_FUNC_SMBUS_I2C_BLOCK)) | |
251 | return -ENODEV; | |
252 | ||
253 | regmap = devm_regmap_init_i2c(client, &isl12057_rtc_regmap_config); | |
254 | if (IS_ERR(regmap)) { | |
255 | ret = PTR_ERR(regmap); | |
256 | dev_err(dev, "regmap allocation failed: %d\n", ret); | |
257 | return ret; | |
258 | } | |
259 | ||
260 | ret = isl12057_i2c_validate_chip(regmap); | |
261 | if (ret) | |
262 | return ret; | |
263 | ||
264 | ret = isl12057_check_rtc_status(dev, regmap); | |
265 | if (ret) | |
266 | return ret; | |
267 | ||
268 | data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); | |
269 | if (!data) | |
270 | return -ENOMEM; | |
271 | ||
272 | mutex_init(&data->lock); | |
273 | data->regmap = regmap; | |
274 | dev_set_drvdata(dev, data); | |
275 | ||
276 | rtc = devm_rtc_device_register(dev, DRV_NAME, &rtc_ops, THIS_MODULE); | |
00b28184 | 277 | return PTR_ERR_OR_ZERO(rtc); |
70e12337 AE |
278 | } |
279 | ||
280 | #ifdef CONFIG_OF | |
281 | static struct of_device_id isl12057_dt_match[] = { | |
282 | { .compatible = "isl,isl12057" }, | |
283 | { }, | |
284 | }; | |
285 | #endif | |
286 | ||
287 | static const struct i2c_device_id isl12057_id[] = { | |
288 | { "isl12057", 0 }, | |
289 | { } | |
290 | }; | |
291 | MODULE_DEVICE_TABLE(i2c, isl12057_id); | |
292 | ||
293 | static struct i2c_driver isl12057_driver = { | |
294 | .driver = { | |
295 | .name = DRV_NAME, | |
296 | .owner = THIS_MODULE, | |
297 | .of_match_table = of_match_ptr(isl12057_dt_match), | |
298 | }, | |
299 | .probe = isl12057_probe, | |
300 | .id_table = isl12057_id, | |
301 | }; | |
302 | module_i2c_driver(isl12057_driver); | |
303 | ||
304 | MODULE_AUTHOR("Arnaud EBALARD <arno@natisbad.org>"); | |
305 | MODULE_DESCRIPTION("Intersil ISL12057 RTC driver"); | |
306 | MODULE_LICENSE("GPL"); |