1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * An I2C driver for the Epson RX8581 RTC |
4 | * |
5 | * Author: Martyn Welch <martyn.welch@ge.com> |
6 | * Copyright 2008 GE Intelligent Platforms Embedded Systems, Inc. |
7 | * |
8 | * Based on: rtc-pcf8563.c (An I2C driver for the Philips PCF8563 RTC) |
9 | * Copyright 2005-06 Tower Technologies |
10 | */ |
11 | |
12 | #include <linux/module.h> |
13 | #include <linux/i2c.h> |
14 | #include <linux/bcd.h> |
15 | #include <linux/of.h> |
16 | #include <linux/regmap.h> |
17 | #include <linux/rtc.h> |
18 | #include <linux/log2.h> |
19 | |
20 | #define RX8581_REG_SC 0x00 /* Second in BCD */ |
21 | #define RX8581_REG_MN 0x01 /* Minute in BCD */ |
22 | #define RX8581_REG_HR 0x02 /* Hour in BCD */ |
23 | #define RX8581_REG_DW 0x03 /* Day of Week */ |
24 | #define RX8581_REG_DM 0x04 /* Day of Month in BCD */ |
25 | #define RX8581_REG_MO 0x05 /* Month in BCD */ |
26 | #define RX8581_REG_YR 0x06 /* Year in BCD */ |
27 | #define RX8581_REG_RAM 0x07 /* RAM */ |
28 | #define RX8581_REG_AMN 0x08 /* Alarm Min in BCD*/ |
29 | #define RX8581_REG_AHR 0x09 /* Alarm Hour in BCD */ |
30 | #define RX8581_REG_ADM 0x0A |
31 | #define RX8581_REG_ADW 0x0A |
32 | #define RX8581_REG_TMR0 0x0B |
33 | #define RX8581_REG_TMR1 0x0C |
34 | #define RX8581_REG_EXT 0x0D /* Extension Register */ |
35 | #define RX8581_REG_FLAG 0x0E /* Flag Register */ |
36 | #define RX8581_REG_CTRL 0x0F /* Control Register */ |
37 | |
38 | |
39 | /* Flag Register bit definitions */ |
40 | #define RX8581_FLAG_UF 0x20 /* Update */ |
41 | #define RX8581_FLAG_TF 0x10 /* Timer */ |
42 | #define RX8581_FLAG_AF 0x08 /* Alarm */ |
43 | #define RX8581_FLAG_VLF 0x02 /* Voltage Low */ |
44 | |
45 | /* Control Register bit definitions */ |
46 | #define RX8581_CTRL_UIE 0x20 /* Update Interrupt Enable */ |
47 | #define RX8581_CTRL_TIE 0x10 /* Timer Interrupt Enable */ |
48 | #define RX8581_CTRL_AIE 0x08 /* Alarm Interrupt Enable */ |
49 | #define RX8581_CTRL_STOP 0x02 /* STOP bit */ |
50 | #define RX8581_CTRL_RESET 0x01 /* RESET bit */ |
51 | |
52 | #define RX8571_USER_RAM 0x10 |
53 | #define RX8571_NVRAM_SIZE 0x10 |
54 | |
55 | struct rx8581 { |
56 | struct regmap *regmap; |
57 | struct rtc_device *rtc; |
58 | }; |
59 | |
60 | struct rx85x1_config { |
61 | struct regmap_config regmap; |
62 | unsigned int num_nvram; |
63 | }; |
64 | |
65 | /* |
66 | * In the routines that deal directly with the rx8581 hardware, we use |
67 | * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch. |
68 | */ |
69 | static int rx8581_rtc_read_time(struct device *dev, struct rtc_time *tm) |
70 | { |
71 | struct i2c_client *client = to_i2c_client(dev); |
72 | unsigned char date[7]; |
73 | unsigned int data; |
74 | int err; |
75 | struct rx8581 *rx8581 = i2c_get_clientdata(client); |
76 | |
77 | /* First we ensure that the "update flag" is not set, we read the |
78 | * time and date then re-read the "update flag". If the update flag |
79 | * has been set, we know that the time has changed during the read so |
80 | * we repeat the whole process again. |
81 | */ |
82 | err = regmap_read(map: rx8581->regmap, RX8581_REG_FLAG, val: &data); |
83 | if (err < 0) |
84 | return err; |
85 | |
86 | if (data & RX8581_FLAG_VLF) { |
87 | dev_warn(dev, |
88 | "low voltage detected, date/time is not reliable.\n" ); |
89 | return -EINVAL; |
90 | } |
91 | |
92 | do { |
93 | /* If update flag set, clear it */ |
94 | if (data & RX8581_FLAG_UF) { |
95 | err = regmap_write(map: rx8581->regmap, RX8581_REG_FLAG, |
96 | val: data & ~RX8581_FLAG_UF); |
97 | if (err < 0) |
98 | return err; |
99 | } |
100 | |
101 | /* Now read time and date */ |
102 | err = regmap_bulk_read(map: rx8581->regmap, RX8581_REG_SC, val: date, |
103 | val_count: sizeof(date)); |
104 | if (err < 0) |
105 | return err; |
106 | |
107 | /* Check flag register */ |
108 | err = regmap_read(map: rx8581->regmap, RX8581_REG_FLAG, val: &data); |
109 | if (err < 0) |
110 | return err; |
111 | } while (data & RX8581_FLAG_UF); |
112 | |
113 | dev_dbg(dev, "%s: raw data is sec=%02x, min=%02x, hr=%02x, " |
114 | "wday=%02x, mday=%02x, mon=%02x, year=%02x\n" , |
115 | __func__, |
116 | date[0], date[1], date[2], date[3], date[4], date[5], date[6]); |
117 | |
118 | tm->tm_sec = bcd2bin(date[RX8581_REG_SC] & 0x7F); |
119 | tm->tm_min = bcd2bin(date[RX8581_REG_MN] & 0x7F); |
120 | tm->tm_hour = bcd2bin(date[RX8581_REG_HR] & 0x3F); /* rtc hr 0-23 */ |
121 | tm->tm_wday = ilog2(date[RX8581_REG_DW] & 0x7F); |
122 | tm->tm_mday = bcd2bin(date[RX8581_REG_DM] & 0x3F); |
123 | tm->tm_mon = bcd2bin(date[RX8581_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */ |
124 | tm->tm_year = bcd2bin(date[RX8581_REG_YR]) + 100; |
125 | |
126 | dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, " |
127 | "mday=%d, mon=%d, year=%d, wday=%d\n" , |
128 | __func__, |
129 | tm->tm_sec, tm->tm_min, tm->tm_hour, |
130 | tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); |
131 | |
132 | return 0; |
133 | } |
134 | |
135 | static int rx8581_rtc_set_time(struct device *dev, struct rtc_time *tm) |
136 | { |
137 | struct i2c_client *client = to_i2c_client(dev); |
138 | int err; |
139 | unsigned char buf[7]; |
140 | struct rx8581 *rx8581 = i2c_get_clientdata(client); |
141 | |
142 | dev_dbg(dev, "%s: secs=%d, mins=%d, hours=%d, " |
143 | "mday=%d, mon=%d, year=%d, wday=%d\n" , |
144 | __func__, |
145 | tm->tm_sec, tm->tm_min, tm->tm_hour, |
146 | tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); |
147 | |
148 | /* hours, minutes and seconds */ |
149 | buf[RX8581_REG_SC] = bin2bcd(tm->tm_sec); |
150 | buf[RX8581_REG_MN] = bin2bcd(tm->tm_min); |
151 | buf[RX8581_REG_HR] = bin2bcd(tm->tm_hour); |
152 | |
153 | buf[RX8581_REG_DM] = bin2bcd(tm->tm_mday); |
154 | |
155 | /* month, 1 - 12 */ |
156 | buf[RX8581_REG_MO] = bin2bcd(tm->tm_mon + 1); |
157 | |
158 | /* year and century */ |
159 | buf[RX8581_REG_YR] = bin2bcd(tm->tm_year - 100); |
160 | buf[RX8581_REG_DW] = (0x1 << tm->tm_wday); |
161 | |
162 | /* Stop the clock */ |
163 | err = regmap_update_bits(map: rx8581->regmap, RX8581_REG_CTRL, |
164 | RX8581_CTRL_STOP, RX8581_CTRL_STOP); |
165 | if (err < 0) |
166 | return err; |
167 | |
168 | /* write register's data */ |
169 | err = regmap_bulk_write(map: rx8581->regmap, RX8581_REG_SC, |
170 | val: buf, val_count: sizeof(buf)); |
171 | if (err < 0) |
172 | return err; |
173 | |
174 | /* get VLF and clear it */ |
175 | err = regmap_update_bits(map: rx8581->regmap, RX8581_REG_FLAG, |
176 | RX8581_FLAG_VLF, val: 0); |
177 | if (err < 0) |
178 | return err; |
179 | |
180 | /* Restart the clock */ |
181 | return regmap_update_bits(map: rx8581->regmap, RX8581_REG_CTRL, |
182 | RX8581_CTRL_STOP, val: 0); |
183 | } |
184 | |
185 | static const struct rtc_class_ops rx8581_rtc_ops = { |
186 | .read_time = rx8581_rtc_read_time, |
187 | .set_time = rx8581_rtc_set_time, |
188 | }; |
189 | |
190 | static int rx8571_nvram_read(void *priv, unsigned int offset, void *val, |
191 | size_t bytes) |
192 | { |
193 | struct rx8581 *rx8581 = priv; |
194 | |
195 | return regmap_bulk_read(map: rx8581->regmap, RX8571_USER_RAM + offset, |
196 | val, val_count: bytes); |
197 | } |
198 | |
199 | static int rx8571_nvram_write(void *priv, unsigned int offset, void *val, |
200 | size_t bytes) |
201 | { |
202 | struct rx8581 *rx8581 = priv; |
203 | |
204 | return regmap_bulk_write(map: rx8581->regmap, RX8571_USER_RAM + offset, |
205 | val, val_count: bytes); |
206 | } |
207 | |
208 | static int rx85x1_nvram_read(void *priv, unsigned int offset, void *val, |
209 | size_t bytes) |
210 | { |
211 | struct rx8581 *rx8581 = priv; |
212 | unsigned int tmp_val; |
213 | int ret; |
214 | |
215 | ret = regmap_read(map: rx8581->regmap, RX8581_REG_RAM, val: &tmp_val); |
216 | (*(unsigned char *)val) = (unsigned char) tmp_val; |
217 | |
218 | return ret; |
219 | } |
220 | |
221 | static int rx85x1_nvram_write(void *priv, unsigned int offset, void *val, |
222 | size_t bytes) |
223 | { |
224 | struct rx8581 *rx8581 = priv; |
225 | unsigned char tmp_val; |
226 | |
227 | tmp_val = *((unsigned char *)val); |
228 | return regmap_write(map: rx8581->regmap, RX8581_REG_RAM, |
229 | val: (unsigned int)tmp_val); |
230 | } |
231 | |
232 | static const struct rx85x1_config rx8581_config = { |
233 | .regmap = { |
234 | .reg_bits = 8, |
235 | .val_bits = 8, |
236 | .max_register = 0xf, |
237 | }, |
238 | .num_nvram = 1 |
239 | }; |
240 | |
241 | static const struct rx85x1_config rx8571_config = { |
242 | .regmap = { |
243 | .reg_bits = 8, |
244 | .val_bits = 8, |
245 | .max_register = 0x1f, |
246 | }, |
247 | .num_nvram = 2 |
248 | }; |
249 | |
250 | static int rx8581_probe(struct i2c_client *client) |
251 | { |
252 | struct rx8581 *rx8581; |
253 | const struct rx85x1_config *config = &rx8581_config; |
254 | const void *data = of_device_get_match_data(dev: &client->dev); |
255 | static struct nvmem_config nvmem_cfg[] = { |
256 | { |
257 | .name = "rx85x1-" , |
258 | .word_size = 1, |
259 | .stride = 1, |
260 | .size = 1, |
261 | .reg_read = rx85x1_nvram_read, |
262 | .reg_write = rx85x1_nvram_write, |
263 | }, { |
264 | .name = "rx8571-" , |
265 | .word_size = 1, |
266 | .stride = 1, |
267 | .size = RX8571_NVRAM_SIZE, |
268 | .reg_read = rx8571_nvram_read, |
269 | .reg_write = rx8571_nvram_write, |
270 | }, |
271 | }; |
272 | int ret, i; |
273 | |
274 | dev_dbg(&client->dev, "%s\n" , __func__); |
275 | |
276 | if (data) |
277 | config = data; |
278 | |
279 | rx8581 = devm_kzalloc(dev: &client->dev, size: sizeof(struct rx8581), GFP_KERNEL); |
280 | if (!rx8581) |
281 | return -ENOMEM; |
282 | |
283 | i2c_set_clientdata(client, data: rx8581); |
284 | |
285 | rx8581->regmap = devm_regmap_init_i2c(client, &config->regmap); |
286 | if (IS_ERR(ptr: rx8581->regmap)) |
287 | return PTR_ERR(ptr: rx8581->regmap); |
288 | |
289 | rx8581->rtc = devm_rtc_allocate_device(dev: &client->dev); |
290 | if (IS_ERR(ptr: rx8581->rtc)) |
291 | return PTR_ERR(ptr: rx8581->rtc); |
292 | |
293 | rx8581->rtc->ops = &rx8581_rtc_ops; |
294 | rx8581->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000; |
295 | rx8581->rtc->range_max = RTC_TIMESTAMP_END_2099; |
296 | rx8581->rtc->start_secs = 0; |
297 | rx8581->rtc->set_start_time = true; |
298 | |
299 | ret = devm_rtc_register_device(rx8581->rtc); |
300 | |
301 | for (i = 0; i < config->num_nvram; i++) { |
302 | nvmem_cfg[i].priv = rx8581; |
303 | devm_rtc_nvmem_register(rtc: rx8581->rtc, nvmem_config: &nvmem_cfg[i]); |
304 | } |
305 | |
306 | return ret; |
307 | } |
308 | |
309 | static const struct i2c_device_id rx8581_id[] = { |
310 | { "rx8581" , 0 }, |
311 | { } |
312 | }; |
313 | MODULE_DEVICE_TABLE(i2c, rx8581_id); |
314 | |
315 | static const __maybe_unused struct of_device_id rx8581_of_match[] = { |
316 | { .compatible = "epson,rx8571" , .data = &rx8571_config }, |
317 | { .compatible = "epson,rx8581" , .data = &rx8581_config }, |
318 | { /* sentinel */ } |
319 | }; |
320 | MODULE_DEVICE_TABLE(of, rx8581_of_match); |
321 | |
322 | static struct i2c_driver rx8581_driver = { |
323 | .driver = { |
324 | .name = "rtc-rx8581" , |
325 | .of_match_table = of_match_ptr(rx8581_of_match), |
326 | }, |
327 | .probe = rx8581_probe, |
328 | .id_table = rx8581_id, |
329 | }; |
330 | |
331 | module_i2c_driver(rx8581_driver); |
332 | |
333 | MODULE_AUTHOR("Martyn Welch <martyn.welch@ge.com>" ); |
334 | MODULE_DESCRIPTION("Epson RX-8571/RX-8581 RTC driver" ); |
335 | MODULE_LICENSE("GPL" ); |
336 | |