tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * An I2C driver for the Epson RX8581 RTC
3 *
4 * Author: Martyn Welch <martyn.welch@ge.com>
5 * Copyright 2008 GE Intelligent Platforms Embedded Systems, Inc.
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 *
11 * Based on: rtc-pcf8563.c (An I2C driver for the Philips PCF8563 RTC)
12 * Copyright 2005-06 Tower Technologies
13 */
14
15#include <linux/module.h>
16#include <linux/i2c.h>
17#include <linux/bcd.h>
18#include <linux/of.h>
19#include <linux/of_device.h>
20#include <linux/regmap.h>
21#include <linux/rtc.h>
22#include <linux/log2.h>
23
24#define RX8581_REG_SC 0x00 /* Second in BCD */
25#define RX8581_REG_MN 0x01 /* Minute in BCD */
26#define RX8581_REG_HR 0x02 /* Hour in BCD */
27#define RX8581_REG_DW 0x03 /* Day of Week */
28#define RX8581_REG_DM 0x04 /* Day of Month in BCD */
29#define RX8581_REG_MO 0x05 /* Month in BCD */
30#define RX8581_REG_YR 0x06 /* Year in BCD */
31#define RX8581_REG_RAM 0x07 /* RAM */
32#define RX8581_REG_AMN 0x08 /* Alarm Min in BCD*/
33#define RX8581_REG_AHR 0x09 /* Alarm Hour in BCD */
34#define RX8581_REG_ADM 0x0A
35#define RX8581_REG_ADW 0x0A
36#define RX8581_REG_TMR0 0x0B
37#define RX8581_REG_TMR1 0x0C
38#define RX8581_REG_EXT 0x0D /* Extension Register */
39#define RX8581_REG_FLAG 0x0E /* Flag Register */
40#define RX8581_REG_CTRL 0x0F /* Control Register */
41
42
43/* Flag Register bit definitions */
44#define RX8581_FLAG_UF 0x20 /* Update */
45#define RX8581_FLAG_TF 0x10 /* Timer */
46#define RX8581_FLAG_AF 0x08 /* Alarm */
47#define RX8581_FLAG_VLF 0x02 /* Voltage Low */
48
49/* Control Register bit definitions */
50#define RX8581_CTRL_UIE 0x20 /* Update Interrupt Enable */
51#define RX8581_CTRL_TIE 0x10 /* Timer Interrupt Enable */
52#define RX8581_CTRL_AIE 0x08 /* Alarm Interrupt Enable */
53#define RX8581_CTRL_STOP 0x02 /* STOP bit */
54#define RX8581_CTRL_RESET 0x01 /* RESET bit */
55
56#define RX8571_USER_RAM 0x10
57#define RX8571_NVRAM_SIZE 0x10
58
59struct rx8581 {
60 struct regmap *regmap;
61 struct rtc_device *rtc;
62};
63
64struct rx85x1_config {
65 struct regmap_config regmap;
66 unsigned int num_nvram;
67};
68
69/*
70 * In the routines that deal directly with the rx8581 hardware, we use
71 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
72 */
73static int rx8581_rtc_read_time(struct device *dev, struct rtc_time *tm)
74{
75 struct i2c_client *client = to_i2c_client(dev);
76 unsigned char date[7];
77 unsigned int data;
78 int err;
79 struct rx8581 *rx8581 = i2c_get_clientdata(client);
80
81 /* First we ensure that the "update flag" is not set, we read the
82 * time and date then re-read the "update flag". If the update flag
83 * has been set, we know that the time has changed during the read so
84 * we repeat the whole process again.
85 */
86 err = regmap_read(rx8581->regmap, RX8581_REG_FLAG, &data);
87 if (err < 0)
88 return err;
89
90 if (data & RX8581_FLAG_VLF) {
91 dev_warn(dev,
92 "low voltage detected, date/time is not reliable.\n");
93 return -EINVAL;
94 }
95
96 do {
97 /* If update flag set, clear it */
98 if (data & RX8581_FLAG_UF) {
99 err = regmap_write(rx8581->regmap, RX8581_REG_FLAG,
100 data & ~RX8581_FLAG_UF);
101 if (err < 0)
102 return err;
103 }
104
105 /* Now read time and date */
106 err = regmap_bulk_read(rx8581->regmap, RX8581_REG_SC, date,
107 sizeof(date));
108 if (err < 0)
109 return err;
110
111 /* Check flag register */
112 err = regmap_read(rx8581->regmap, RX8581_REG_FLAG, &data);
113 if (err < 0)
114 return err;
115 } while (data & RX8581_FLAG_UF);
116
117 dev_dbg(dev, "%s: raw data is sec=%02x, min=%02x, hr=%02x, "
118 "wday=%02x, mday=%02x, mon=%02x, year=%02x\n",
119 __func__,
120 date[0], date[1], date[2], date[3], date[4], date[5], date[6]);
121
122 tm->tm_sec = bcd2bin(date[RX8581_REG_SC] & 0x7F);
123 tm->tm_min = bcd2bin(date[RX8581_REG_MN] & 0x7F);
124 tm->tm_hour = bcd2bin(date[RX8581_REG_HR] & 0x3F); /* rtc hr 0-23 */
125 tm->tm_wday = ilog2(date[RX8581_REG_DW] & 0x7F);
126 tm->tm_mday = bcd2bin(date[RX8581_REG_DM] & 0x3F);
127 tm->tm_mon = bcd2bin(date[RX8581_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
128 tm->tm_year = bcd2bin(date[RX8581_REG_YR]) + 100;
129
130 dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
131 "mday=%d, mon=%d, year=%d, wday=%d\n",
132 __func__,
133 tm->tm_sec, tm->tm_min, tm->tm_hour,
134 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
135
136 return 0;
137}
138
139static int rx8581_rtc_set_time(struct device *dev, struct rtc_time *tm)
140{
141 struct i2c_client *client = to_i2c_client(dev);
142 int err;
143 unsigned char buf[7];
144 struct rx8581 *rx8581 = i2c_get_clientdata(client);
145
146 dev_dbg(dev, "%s: secs=%d, mins=%d, hours=%d, "
147 "mday=%d, mon=%d, year=%d, wday=%d\n",
148 __func__,
149 tm->tm_sec, tm->tm_min, tm->tm_hour,
150 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
151
152 /* hours, minutes and seconds */
153 buf[RX8581_REG_SC] = bin2bcd(tm->tm_sec);
154 buf[RX8581_REG_MN] = bin2bcd(tm->tm_min);
155 buf[RX8581_REG_HR] = bin2bcd(tm->tm_hour);
156
157 buf[RX8581_REG_DM] = bin2bcd(tm->tm_mday);
158
159 /* month, 1 - 12 */
160 buf[RX8581_REG_MO] = bin2bcd(tm->tm_mon + 1);
161
162 /* year and century */
163 buf[RX8581_REG_YR] = bin2bcd(tm->tm_year - 100);
164 buf[RX8581_REG_DW] = (0x1 << tm->tm_wday);
165
166 /* Stop the clock */
167 err = regmap_update_bits(rx8581->regmap, RX8581_REG_CTRL,
168 RX8581_CTRL_STOP, RX8581_CTRL_STOP);
169 if (err < 0)
170 return err;
171
172 /* write register's data */
173 err = regmap_bulk_write(rx8581->regmap, RX8581_REG_SC,
174 buf, sizeof(buf));
175 if (err < 0)
176 return err;
177
178 /* get VLF and clear it */
179 err = regmap_update_bits(rx8581->regmap, RX8581_REG_FLAG,
180 RX8581_FLAG_VLF, 0);
181 if (err < 0)
182 return err;
183
184 /* Restart the clock */
185 return regmap_update_bits(rx8581->regmap, RX8581_REG_CTRL,
186 RX8581_CTRL_STOP, 0);
187}
188
189static const struct rtc_class_ops rx8581_rtc_ops = {
190 .read_time = rx8581_rtc_read_time,
191 .set_time = rx8581_rtc_set_time,
192};
193
194static int rx8571_nvram_read(void *priv, unsigned int offset, void *val,
195 size_t bytes)
196{
197 struct rx8581 *rx8581 = priv;
198
199 return regmap_bulk_read(rx8581->regmap, RX8571_USER_RAM + offset,
200 val, bytes);
201}
202
203static int rx8571_nvram_write(void *priv, unsigned int offset, void *val,
204 size_t bytes)
205{
206 struct rx8581 *rx8581 = priv;
207
208 return regmap_bulk_write(rx8581->regmap, RX8571_USER_RAM + offset,
209 val, bytes);
210}
211
212static int rx85x1_nvram_read(void *priv, unsigned int offset, void *val,
213 size_t bytes)
214{
215 struct rx8581 *rx8581 = priv;
216 unsigned int tmp_val;
217 int ret;
218
219 ret = regmap_read(rx8581->regmap, RX8581_REG_RAM, &tmp_val);
220 (*(unsigned char *)val) = (unsigned char) tmp_val;
221
222 return ret;
223}
224
225static int rx85x1_nvram_write(void *priv, unsigned int offset, void *val,
226 size_t bytes)
227{
228 struct rx8581 *rx8581 = priv;
229 unsigned char tmp_val;
230
231 tmp_val = *((unsigned char *)val);
232 return regmap_write(rx8581->regmap, RX8581_REG_RAM,
233 (unsigned int)tmp_val);
234}
235
236static const struct rx85x1_config rx8581_config = {
237 .regmap = {
238 .reg_bits = 8,
239 .val_bits = 8,
240 .max_register = 0xf,
241 },
242 .num_nvram = 1
243};
244
245static const struct rx85x1_config rx8571_config = {
246 .regmap = {
247 .reg_bits = 8,
248 .val_bits = 8,
249 .max_register = 0x1f,
250 },
251 .num_nvram = 2
252};
253
254static int rx8581_probe(struct i2c_client *client,
255 const struct i2c_device_id *id)
256{
257 struct rx8581 *rx8581;
258 const struct rx85x1_config *config = &rx8581_config;
259 const void *data = of_device_get_match_data(&client->dev);
260 static struct nvmem_config nvmem_cfg[] = {
261 {
262 .name = "rx85x1-",
263 .word_size = 1,
264 .stride = 1,
265 .size = 1,
266 .reg_read = rx85x1_nvram_read,
267 .reg_write = rx85x1_nvram_write,
268 }, {
269 .name = "rx8571-",
270 .word_size = 1,
271 .stride = 1,
272 .size = RX8571_NVRAM_SIZE,
273 .reg_read = rx8571_nvram_read,
274 .reg_write = rx8571_nvram_write,
275 },
276 };
277 int ret, i;
278
279 dev_dbg(&client->dev, "%s\n", __func__);
280
281 if (data)
282 config = data;
283
284 rx8581 = devm_kzalloc(&client->dev, sizeof(struct rx8581), GFP_KERNEL);
285 if (!rx8581)
286 return -ENOMEM;
287
288 i2c_set_clientdata(client, rx8581);
289
290 rx8581->regmap = devm_regmap_init_i2c(client, &config->regmap);
291 if (IS_ERR(rx8581->regmap))
292 return PTR_ERR(rx8581->regmap);
293
294 rx8581->rtc = devm_rtc_allocate_device(&client->dev);
295 if (IS_ERR(rx8581->rtc))
296 return PTR_ERR(rx8581->rtc);
297
298 rx8581->rtc->ops = &rx8581_rtc_ops;
299 rx8581->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
300 rx8581->rtc->range_max = RTC_TIMESTAMP_END_2099;
301 rx8581->rtc->start_secs = 0;
302 rx8581->rtc->set_start_time = true;
303
304 ret = rtc_register_device(rx8581->rtc);
305
306 for (i = 0; i < config->num_nvram; i++) {
307 nvmem_cfg[i].priv = rx8581;
308 rtc_nvmem_register(rx8581->rtc, &nvmem_cfg[i]);
309 }
310
311 return ret;
312}
313
314static const struct i2c_device_id rx8581_id[] = {
315 { "rx8581", 0 },
316 { }
317};
318MODULE_DEVICE_TABLE(i2c, rx8581_id);
319
320static const struct of_device_id rx8581_of_match[] = {
321 { .compatible = "epson,rx8571", .data = &rx8571_config },
322 { .compatible = "epson,rx8581", .data = &rx8581_config },
323 { /* sentinel */ }
324};
325MODULE_DEVICE_TABLE(of, rx8581_of_match);
326
327static struct i2c_driver rx8581_driver = {
328 .driver = {
329 .name = "rtc-rx8581",
330 .of_match_table = of_match_ptr(rx8581_of_match),
331 },
332 .probe = rx8581_probe,
333 .id_table = rx8581_id,
334};
335
336module_i2c_driver(rx8581_driver);
337
338MODULE_AUTHOR("Martyn Welch <martyn.welch@ge.com>");
339MODULE_DESCRIPTION("Epson RX-8571/RX-8581 RTC driver");
340MODULE_LICENSE("GPL");