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/of_device.h>
17 #include <linux/regmap.h>
18 #include <linux/rtc.h>
19 #include <linux/log2.h>
20
21 #define RX8581_REG_SC 0x00 /* Second in BCD */
22 #define RX8581_REG_MN 0x01 /* Minute in BCD */
23 #define RX8581_REG_HR 0x02 /* Hour in BCD */
24 #define RX8581_REG_DW 0x03 /* Day of Week */
25 #define RX8581_REG_DM 0x04 /* Day of Month in BCD */
26 #define RX8581_REG_MO 0x05 /* Month in BCD */
27 #define RX8581_REG_YR 0x06 /* Year in BCD */
28 #define RX8581_REG_RAM 0x07 /* RAM */
29 #define RX8581_REG_AMN 0x08 /* Alarm Min in BCD*/
30 #define RX8581_REG_AHR 0x09 /* Alarm Hour in BCD */
31 #define RX8581_REG_ADM 0x0A
32 #define RX8581_REG_ADW 0x0A
33 #define RX8581_REG_TMR0 0x0B
34 #define RX8581_REG_TMR1 0x0C
35 #define RX8581_REG_EXT 0x0D /* Extension Register */
36 #define RX8581_REG_FLAG 0x0E /* Flag Register */
37 #define RX8581_REG_CTRL 0x0F /* Control Register */
38
39
40 /* Flag Register bit definitions */
41 #define RX8581_FLAG_UF 0x20 /* Update */
42 #define RX8581_FLAG_TF 0x10 /* Timer */
43 #define RX8581_FLAG_AF 0x08 /* Alarm */
44 #define RX8581_FLAG_VLF 0x02 /* Voltage Low */
45
46 /* Control Register bit definitions */
47 #define RX8581_CTRL_UIE 0x20 /* Update Interrupt Enable */
48 #define RX8581_CTRL_TIE 0x10 /* Timer Interrupt Enable */
49 #define RX8581_CTRL_AIE 0x08 /* Alarm Interrupt Enable */
50 #define RX8581_CTRL_STOP 0x02 /* STOP bit */
51 #define RX8581_CTRL_RESET 0x01 /* RESET bit */
52
53 #define RX8571_USER_RAM 0x10
54 #define RX8571_NVRAM_SIZE 0x10
55
56 struct rx8581 {
57 struct regmap *regmap;
58 struct rtc_device *rtc;
59 };
60
61 struct rx85x1_config {
62 struct regmap_config regmap;
63 unsigned int num_nvram;
64 };
65
66 /*
67 * In the routines that deal directly with the rx8581 hardware, we use
68 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
69 */
rx8581_rtc_read_time(struct device * dev,struct rtc_time * tm)70 static int rx8581_rtc_read_time(struct device *dev, struct rtc_time *tm)
71 {
72 struct i2c_client *client = to_i2c_client(dev);
73 unsigned char date[7];
74 unsigned int data;
75 int err;
76 struct rx8581 *rx8581 = i2c_get_clientdata(client);
77
78 /* First we ensure that the "update flag" is not set, we read the
79 * time and date then re-read the "update flag". If the update flag
80 * has been set, we know that the time has changed during the read so
81 * we repeat the whole process again.
82 */
83 err = regmap_read(rx8581->regmap, RX8581_REG_FLAG, &data);
84 if (err < 0)
85 return err;
86
87 if (data & RX8581_FLAG_VLF) {
88 dev_warn(dev,
89 "low voltage detected, date/time is not reliable.\n");
90 return -EINVAL;
91 }
92
93 do {
94 /* If update flag set, clear it */
95 if (data & RX8581_FLAG_UF) {
96 err = regmap_write(rx8581->regmap, RX8581_REG_FLAG,
97 data & ~RX8581_FLAG_UF);
98 if (err < 0)
99 return err;
100 }
101
102 /* Now read time and date */
103 err = regmap_bulk_read(rx8581->regmap, RX8581_REG_SC, date,
104 sizeof(date));
105 if (err < 0)
106 return err;
107
108 /* Check flag register */
109 err = regmap_read(rx8581->regmap, RX8581_REG_FLAG, &data);
110 if (err < 0)
111 return err;
112 } while (data & RX8581_FLAG_UF);
113
114 dev_dbg(dev, "%s: raw data is sec=%02x, min=%02x, hr=%02x, "
115 "wday=%02x, mday=%02x, mon=%02x, year=%02x\n",
116 __func__,
117 date[0], date[1], date[2], date[3], date[4], date[5], date[6]);
118
119 tm->tm_sec = bcd2bin(date[RX8581_REG_SC] & 0x7F);
120 tm->tm_min = bcd2bin(date[RX8581_REG_MN] & 0x7F);
121 tm->tm_hour = bcd2bin(date[RX8581_REG_HR] & 0x3F); /* rtc hr 0-23 */
122 tm->tm_wday = ilog2(date[RX8581_REG_DW] & 0x7F);
123 tm->tm_mday = bcd2bin(date[RX8581_REG_DM] & 0x3F);
124 tm->tm_mon = bcd2bin(date[RX8581_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
125 tm->tm_year = bcd2bin(date[RX8581_REG_YR]) + 100;
126
127 dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
128 "mday=%d, mon=%d, year=%d, wday=%d\n",
129 __func__,
130 tm->tm_sec, tm->tm_min, tm->tm_hour,
131 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
132
133 return 0;
134 }
135
rx8581_rtc_set_time(struct device * dev,struct rtc_time * tm)136 static int rx8581_rtc_set_time(struct device *dev, struct rtc_time *tm)
137 {
138 struct i2c_client *client = to_i2c_client(dev);
139 int err;
140 unsigned char buf[7];
141 struct rx8581 *rx8581 = i2c_get_clientdata(client);
142
143 dev_dbg(dev, "%s: secs=%d, mins=%d, hours=%d, "
144 "mday=%d, mon=%d, year=%d, wday=%d\n",
145 __func__,
146 tm->tm_sec, tm->tm_min, tm->tm_hour,
147 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
148
149 /* hours, minutes and seconds */
150 buf[RX8581_REG_SC] = bin2bcd(tm->tm_sec);
151 buf[RX8581_REG_MN] = bin2bcd(tm->tm_min);
152 buf[RX8581_REG_HR] = bin2bcd(tm->tm_hour);
153
154 buf[RX8581_REG_DM] = bin2bcd(tm->tm_mday);
155
156 /* month, 1 - 12 */
157 buf[RX8581_REG_MO] = bin2bcd(tm->tm_mon + 1);
158
159 /* year and century */
160 buf[RX8581_REG_YR] = bin2bcd(tm->tm_year - 100);
161 buf[RX8581_REG_DW] = (0x1 << tm->tm_wday);
162
163 /* Stop the clock */
164 err = regmap_update_bits(rx8581->regmap, RX8581_REG_CTRL,
165 RX8581_CTRL_STOP, RX8581_CTRL_STOP);
166 if (err < 0)
167 return err;
168
169 /* write register's data */
170 err = regmap_bulk_write(rx8581->regmap, RX8581_REG_SC,
171 buf, sizeof(buf));
172 if (err < 0)
173 return err;
174
175 /* get VLF and clear it */
176 err = regmap_update_bits(rx8581->regmap, RX8581_REG_FLAG,
177 RX8581_FLAG_VLF, 0);
178 if (err < 0)
179 return err;
180
181 /* Restart the clock */
182 return regmap_update_bits(rx8581->regmap, RX8581_REG_CTRL,
183 RX8581_CTRL_STOP, 0);
184 }
185
186 static const struct rtc_class_ops rx8581_rtc_ops = {
187 .read_time = rx8581_rtc_read_time,
188 .set_time = rx8581_rtc_set_time,
189 };
190
rx8571_nvram_read(void * priv,unsigned int offset,void * val,size_t bytes)191 static int rx8571_nvram_read(void *priv, unsigned int offset, void *val,
192 size_t bytes)
193 {
194 struct rx8581 *rx8581 = priv;
195
196 return regmap_bulk_read(rx8581->regmap, RX8571_USER_RAM + offset,
197 val, bytes);
198 }
199
rx8571_nvram_write(void * priv,unsigned int offset,void * val,size_t bytes)200 static int rx8571_nvram_write(void *priv, unsigned int offset, void *val,
201 size_t bytes)
202 {
203 struct rx8581 *rx8581 = priv;
204
205 return regmap_bulk_write(rx8581->regmap, RX8571_USER_RAM + offset,
206 val, bytes);
207 }
208
rx85x1_nvram_read(void * priv,unsigned int offset,void * val,size_t bytes)209 static int rx85x1_nvram_read(void *priv, unsigned int offset, void *val,
210 size_t bytes)
211 {
212 struct rx8581 *rx8581 = priv;
213 unsigned int tmp_val;
214 int ret;
215
216 ret = regmap_read(rx8581->regmap, RX8581_REG_RAM, &tmp_val);
217 (*(unsigned char *)val) = (unsigned char) tmp_val;
218
219 return ret;
220 }
221
rx85x1_nvram_write(void * priv,unsigned int offset,void * val,size_t bytes)222 static int rx85x1_nvram_write(void *priv, unsigned int offset, void *val,
223 size_t bytes)
224 {
225 struct rx8581 *rx8581 = priv;
226 unsigned char tmp_val;
227
228 tmp_val = *((unsigned char *)val);
229 return regmap_write(rx8581->regmap, RX8581_REG_RAM,
230 (unsigned int)tmp_val);
231 }
232
233 static const struct rx85x1_config rx8581_config = {
234 .regmap = {
235 .reg_bits = 8,
236 .val_bits = 8,
237 .max_register = 0xf,
238 },
239 .num_nvram = 1
240 };
241
242 static const struct rx85x1_config rx8571_config = {
243 .regmap = {
244 .reg_bits = 8,
245 .val_bits = 8,
246 .max_register = 0x1f,
247 },
248 .num_nvram = 2
249 };
250
rx8581_probe(struct i2c_client * client,const struct i2c_device_id * id)251 static int rx8581_probe(struct i2c_client *client,
252 const struct i2c_device_id *id)
253 {
254 struct rx8581 *rx8581;
255 const struct rx85x1_config *config = &rx8581_config;
256 const void *data = of_device_get_match_data(&client->dev);
257 static struct nvmem_config nvmem_cfg[] = {
258 {
259 .name = "rx85x1-",
260 .word_size = 1,
261 .stride = 1,
262 .size = 1,
263 .reg_read = rx85x1_nvram_read,
264 .reg_write = rx85x1_nvram_write,
265 }, {
266 .name = "rx8571-",
267 .word_size = 1,
268 .stride = 1,
269 .size = RX8571_NVRAM_SIZE,
270 .reg_read = rx8571_nvram_read,
271 .reg_write = rx8571_nvram_write,
272 },
273 };
274 int ret, i;
275
276 dev_dbg(&client->dev, "%s\n", __func__);
277
278 if (data)
279 config = data;
280
281 rx8581 = devm_kzalloc(&client->dev, sizeof(struct rx8581), GFP_KERNEL);
282 if (!rx8581)
283 return -ENOMEM;
284
285 i2c_set_clientdata(client, rx8581);
286
287 rx8581->regmap = devm_regmap_init_i2c(client, &config->regmap);
288 if (IS_ERR(rx8581->regmap))
289 return PTR_ERR(rx8581->regmap);
290
291 rx8581->rtc = devm_rtc_allocate_device(&client->dev);
292 if (IS_ERR(rx8581->rtc))
293 return PTR_ERR(rx8581->rtc);
294
295 rx8581->rtc->ops = &rx8581_rtc_ops;
296 rx8581->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
297 rx8581->rtc->range_max = RTC_TIMESTAMP_END_2099;
298 rx8581->rtc->start_secs = 0;
299 rx8581->rtc->set_start_time = true;
300
301 ret = rtc_register_device(rx8581->rtc);
302
303 for (i = 0; i < config->num_nvram; i++) {
304 nvmem_cfg[i].priv = rx8581;
305 rtc_nvmem_register(rx8581->rtc, &nvmem_cfg[i]);
306 }
307
308 return ret;
309 }
310
311 static const struct i2c_device_id rx8581_id[] = {
312 { "rx8581", 0 },
313 { }
314 };
315 MODULE_DEVICE_TABLE(i2c, rx8581_id);
316
317 static const struct of_device_id rx8581_of_match[] = {
318 { .compatible = "epson,rx8571", .data = &rx8571_config },
319 { .compatible = "epson,rx8581", .data = &rx8581_config },
320 { /* sentinel */ }
321 };
322 MODULE_DEVICE_TABLE(of, rx8581_of_match);
323
324 static struct i2c_driver rx8581_driver = {
325 .driver = {
326 .name = "rtc-rx8581",
327 .of_match_table = of_match_ptr(rx8581_of_match),
328 },
329 .probe = rx8581_probe,
330 .id_table = rx8581_id,
331 };
332
333 module_i2c_driver(rx8581_driver);
334
335 MODULE_AUTHOR("Martyn Welch <martyn.welch@ge.com>");
336 MODULE_DESCRIPTION("Epson RX-8571/RX-8581 RTC driver");
337 MODULE_LICENSE("GPL");
338
