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Nandor Handa5337a2017-11-08 15:35:14 +00001/*
2 * SII Semiconductor Corporation S35392A RTC driver.
3 *
4 * Copyright (c) 2017, General Electric Company
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms and conditions of the GNU General Public License,
8 * version 2, as published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
13 * more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program. If not, see <http://www.gnu.org/licenses/>.
17 *
18 * SPDX-License-Identifier: GPL-2.0
19 */
20
21#include <command.h>
22#include <common.h>
23#include <dm.h>
24#include <i2c.h>
25#include <linux/bitrev.h>
26#include <rtc.h>
27
28#define S35390A_CMD_STATUS1 0x30
29#define S35390A_CMD_STATUS2 0x31
30#define S35390A_CMD_TIME1 0x32
31#define S35390A_CMD_TIME2 0x33
32#define S35390A_CMD_INT2_REG1 0x35
33
34#define S35390A_BYTE_YEAR 0
35#define S35390A_BYTE_MONTH 1
36#define S35390A_BYTE_DAY 2
37#define S35390A_BYTE_WDAY 3
38#define S35390A_BYTE_HOURS 4
39#define S35390A_BYTE_MINS 5
40#define S35390A_BYTE_SECS 6
41
42/* flags for STATUS1 */
43#define S35390A_FLAG_POC 0x01
44#define S35390A_FLAG_BLD 0x02
45#define S35390A_FLAG_INT2 0x04
46#define S35390A_FLAG_24H 0x40
47#define S35390A_FLAG_RESET 0x80
48
49/*
50 * If either BLD or POC is set, then the chip has lost power long enough for
51 * the time value to become invalid.
52 */
53#define S35390A_LOW_VOLTAGE (S35390A_FLAG_POC | S35390A_FLAG_BLD)
54
55/*---------------------------------------------------------------------*/
56#undef DEBUG_RTC
57
58#ifdef DEBUG_RTC
59#define DEBUGR(fmt, args...) printf(fmt, ##args)
60#else
61#define DEBUGR(fmt, args...)
62#endif
63/*---------------------------------------------------------------------*/
64
65#ifdef CONFIG_DM_RTC
66#define DEV_TYPE struct udevice
67#else
68/* Local udevice */
69struct ludevice {
70 u8 chip;
71};
72
73#define DEV_TYPE struct ludevice
74struct ludevice dev;
75
76#endif
77
78#define msleep(a) udelay(a * 1000)
79
80int lowvoltage;
81
82static int s35392a_rtc_reset(DEV_TYPE *dev);
83
84static int s35392a_rtc_read(DEV_TYPE *dev, u8 reg, u8 *buf, int len)
85{
86 int ret;
87
88#ifdef CONFIG_DM_RTC
89 /* TODO: we need to tweak the chip address to reg */
90 ret = dm_i2c_read(dev, 0, buf, len);
91#else
92 (void)dev;
93 ret = i2c_read(reg, 0, -1, buf, len);
94#endif
95
96 return ret;
97}
98
99static int s35392a_rtc_write(DEV_TYPE *dev, u8 reg, u8 *buf, int len)
100{
101 int ret;
102
103#ifdef CONFIG_DM_RTC
104 /* TODO: we need to tweak the chip address to reg */
105 ret = dm_i2c_write(dev, 0, buf, 1);
106#else
107 (void)dev;
108 ret = i2c_write(reg, 0, 0, buf, len);
109#endif
110
111 return ret;
112}
113
114static int s35392a_rtc_read8(DEV_TYPE *dev, unsigned int reg)
115{
116 u8 val;
117 int ret;
118
119 ret = s35392a_rtc_read(dev, reg, &val, sizeof(val));
120 return ret < 0 ? ret : val;
121}
122
123static int s35392a_rtc_write8(DEV_TYPE *dev, unsigned int reg, int val)
124{
125 int ret;
126 u8 lval = val;
127
128 ret = s35392a_rtc_write(dev, reg, &lval, sizeof(lval));
129 return ret < 0 ? ret : 0;
130}
131
132static int validate_time(const struct rtc_time *tm)
133{
134 if ((tm->tm_year < 2000) || (tm->tm_year > 2099))
135 return -EINVAL;
136
137 if ((tm->tm_mon < 1) || (tm->tm_mon > 12))
138 return -EINVAL;
139
140 if ((tm->tm_mday < 1) || (tm->tm_mday > 31))
141 return -EINVAL;
142
143 if ((tm->tm_wday < 0) || (tm->tm_wday > 6))
144 return -EINVAL;
145
146 if ((tm->tm_hour < 0) || (tm->tm_hour > 23))
147 return -EINVAL;
148
149 if ((tm->tm_min < 0) || (tm->tm_min > 59))
150 return -EINVAL;
151
152 if ((tm->tm_sec < 0) || (tm->tm_sec > 59))
153 return -EINVAL;
154
155 return 0;
156}
157
158void s35392a_rtc_init(DEV_TYPE *dev)
159{
160 int status;
161
162 status = s35392a_rtc_read8(dev, S35390A_CMD_STATUS1);
163 if (status < 0)
164 goto error;
165
166 DEBUGR("init: S35390A_CMD_STATUS1: 0x%x\n", status);
167
168 lowvoltage = status & S35390A_LOW_VOLTAGE ? 1 : 0;
169
170 if (status & S35390A_FLAG_POC)
171 /*
172 * Do not communicate for 0.5 seconds since the power-on
173 * detection circuit is in operation.
174 */
175 msleep(500);
176
177 else if (!lowvoltage)
178 /*
179 * If both POC and BLD are unset everything is fine.
180 */
181 return;
182
183 if (lowvoltage)
184 printf("RTC low voltage detected\n");
185
186 if (!s35392a_rtc_reset(dev))
187 return;
188
189error:
190 printf("Error RTC init.\n");
191}
192
193/* Get the current time from the RTC */
194static int s35392a_rtc_get(DEV_TYPE *dev, struct rtc_time *tm)
195{
196 u8 date[7];
197 int ret, i;
198
199 if (lowvoltage) {
200 DEBUGR("RTC low voltage detected\n");
201 return -EINVAL;
202 }
203
204 ret = s35392a_rtc_read(dev, S35390A_CMD_TIME1, date, sizeof(date));
205 if (ret < 0) {
206 DEBUGR("Error reading date from RTC\n");
207 return -EIO;
208 }
209
210 /* This chip returns the bits of each byte in reverse order */
211 for (i = 0; i < 7; ++i)
212 date[i] = bitrev8(date[i]);
213
214 tm->tm_sec = bcd2bin(date[S35390A_BYTE_SECS]);
215 tm->tm_min = bcd2bin(date[S35390A_BYTE_MINS]);
216 tm->tm_hour = bcd2bin(date[S35390A_BYTE_HOURS] & ~S35390A_FLAG_24H);
217 tm->tm_wday = bcd2bin(date[S35390A_BYTE_WDAY]);
218 tm->tm_mday = bcd2bin(date[S35390A_BYTE_DAY]);
219 tm->tm_mon = bcd2bin(date[S35390A_BYTE_MONTH]);
220 tm->tm_year = bcd2bin(date[S35390A_BYTE_YEAR]) + 2000;
221
222 DEBUGR("Get DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
223 tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_wday,
224 tm->tm_hour, tm->tm_min, tm->tm_sec);
225
226 return 0;
227}
228
229/* Set the RTC */
230static int s35392a_rtc_set(DEV_TYPE *dev, const struct rtc_time *tm)
231{
232 int i, ret;
233 int status;
234 u8 date[7];
235
236 DEBUGR("Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
237 tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_wday,
238 tm->tm_hour, tm->tm_min, tm->tm_sec);
239
240 ret = validate_time(tm);
241 if (ret < 0)
242 return -EINVAL;
243
244 /* We support only 24h mode */
245 ret = s35392a_rtc_read8(dev, S35390A_CMD_STATUS1);
246 if (ret < 0)
247 return -EIO;
248 status = ret;
249
250 ret = s35392a_rtc_write8(dev, S35390A_CMD_STATUS1,
251 status | S35390A_FLAG_24H);
252 if (ret < 0)
253 return -EIO;
254
255 date[S35390A_BYTE_YEAR] = bin2bcd(tm->tm_year - 2000);
256 date[S35390A_BYTE_MONTH] = bin2bcd(tm->tm_mon);
257 date[S35390A_BYTE_DAY] = bin2bcd(tm->tm_mday);
258 date[S35390A_BYTE_WDAY] = bin2bcd(tm->tm_wday);
259 date[S35390A_BYTE_HOURS] = bin2bcd(tm->tm_hour);
260 date[S35390A_BYTE_MINS] = bin2bcd(tm->tm_min);
261 date[S35390A_BYTE_SECS] = bin2bcd(tm->tm_sec);
262
263 /* This chip expects the bits of each byte to be in reverse order */
264 for (i = 0; i < 7; ++i)
265 date[i] = bitrev8(date[i]);
266
267 ret = s35392a_rtc_write(dev, S35390A_CMD_TIME1, date, sizeof(date));
268 if (ret < 0) {
269 DEBUGR("Error writing date to RTC\n");
270 return -EIO;
271 }
272
273 /* Now we have time. Reset the low voltage status */
274 lowvoltage = 0;
275
276 return 0;
277}
278
279/* Reset the RTC. */
280static int s35392a_rtc_reset(DEV_TYPE *dev)
281{
282 int buf;
283 int ret;
284 unsigned int initcount = 0;
285
286 buf = S35390A_FLAG_RESET;
287
288initialize:
289 ret = s35392a_rtc_write8(dev, S35390A_CMD_STATUS1, buf);
290 if (ret < 0)
291 return -EIO;
292
293 ret = s35392a_rtc_read8(dev, S35390A_CMD_STATUS1);
294 if (ret < 0)
295 return -EIO;
296 buf = ret;
297
298 if (!lowvoltage)
299 lowvoltage = buf & S35390A_LOW_VOLTAGE ? 1 : 0;
300
301 if (buf & S35390A_LOW_VOLTAGE) {
302 /* Try up to five times to reset the chip */
303 if (initcount < 5) {
304 ++initcount;
305 goto initialize;
306 } else {
307 return -EIO;
308 }
309 }
310
311 return 0;
312}
313
314#ifndef CONFIG_DM_RTC
315
316int rtc_get(struct rtc_time *tm)
317{
318 return s35392a_rtc_get(&dev, tm);
319}
320
321int rtc_set(struct rtc_time *tm)
322{
323 return s35392a_rtc_set(&dev, tm);
324}
325
326void rtc_reset(void)
327{
328 s35392a_rtc_reset(&dev);
329}
330
331void rtc_init(void)
332{
333 s35392a_rtc_init(&dev);
334}
335
336#else
337
338static int s35392a_probe(struct udevice *dev)
339{
340 s35392a_rtc_init(dev);
341 return 0;
342}
343
344static const struct rtc_ops s35392a_rtc_ops = {
345 .get = s35392a_rtc_get,
346 .set = s35392a_rtc_set,
347 .read8 = s35392a_rtc_read8,
348 .write8 = s35392a_rtc_write8,
349 .reset = s35392a_rtc_reset,
350};
351
352static const struct udevice_id s35392a_rtc_ids[] = {
353 { .compatible = "sii,s35392a-rtc" },
354 { }
355};
356
357U_BOOT_DRIVER(s35392a_rtc) = {
358 .name = "s35392a_rtc",
359 .id = UCLASS_RTC,
360 .probe = s35392a_probe,
361 .of_match = s35392a_rtc_ids,
362 .ops = &s35392a_rtc_ops,
363};
364
365#endif