1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * (C) Copyright 2007
4 * Matthias Fuchs, esd gmbh, matthias.fuchs@esd-electronics.com.
5 */
6
7 /*
8 * Epson RX8025 RTC driver.
9 */
10
11 #include <common.h>
12 #include <command.h>
13 #include <dm.h>
14 #include <i2c.h>
15 #include <rtc.h>
16
17 /*---------------------------------------------------------------------*/
18 #undef DEBUG_RTC
19
20 #ifdef DEBUG_RTC
21 #define DEBUGR(fmt,args...) printf(fmt ,##args)
22 #else
23 #define DEBUGR(fmt,args...)
24 #endif
25 /*---------------------------------------------------------------------*/
26
27 enum rx_model {
28 model_rx_8025,
29 model_rx_8035,
30 };
31
32 /*
33 * RTC register addresses
34 */
35 #define RTC_SEC_REG_ADDR 0x00
36 #define RTC_MIN_REG_ADDR 0x01
37 #define RTC_HR_REG_ADDR 0x02
38 #define RTC_DAY_REG_ADDR 0x03
39 #define RTC_DATE_REG_ADDR 0x04
40 #define RTC_MON_REG_ADDR 0x05
41 #define RTC_YR_REG_ADDR 0x06
42 #define RTC_OFFSET_REG_ADDR 0x07
43
44 #define RTC_CTL1_REG_ADDR 0x0e
45 #define RTC_CTL2_REG_ADDR 0x0f
46
47 /*
48 * Control register 1 bits
49 */
50 #define RTC_CTL1_BIT_2412 0x20
51
52 /*
53 * Control register 2 bits
54 */
55 #define RTC_CTL2_BIT_PON 0x10
56 #define RTC_CTL2_BIT_VDET 0x40
57 #define RTC_CTL2_BIT_XST 0x20
58 #define RTC_CTL2_BIT_VDSL 0x80
59
60 /*
61 * Note: the RX8025 I2C RTC requires register
62 * reads and write to consist of a single bus
63 * cycle. It is not allowed to write the register
64 * address in a first cycle that is terminated by
65 * a STOP condition. The chips needs a 'restart'
66 * sequence (start sequence without a prior stop).
67 */
68
69 #define rtc_read(reg) buf[(reg) & 0xf]
70
71 static int rtc_write(struct udevice *dev, uchar reg, uchar val);
72
rx8025_is_osc_stopped(enum rx_model model,int ctrl2)73 static int rx8025_is_osc_stopped(enum rx_model model, int ctrl2)
74 {
75 int xstp = ctrl2 & RTC_CTL2_BIT_XST;
76 /* XSTP bit has different polarity on RX-8025 vs RX-8035.
77 * RX-8025: 0 == oscillator stopped
78 * RX-8035: 1 == oscillator stopped
79 */
80
81 if (model == model_rx_8025)
82 xstp = !xstp;
83
84 return xstp;
85 }
86
87 /*
88 * Get the current time from the RTC
89 */
rx8025_rtc_get(struct udevice * dev,struct rtc_time * tmp)90 static int rx8025_rtc_get(struct udevice *dev, struct rtc_time *tmp)
91 {
92 int rel = 0;
93 uchar sec, min, hour, mday, wday, mon, year, ctl2;
94 uchar buf[16];
95
96 if (dm_i2c_read(dev, 0, buf, sizeof(buf))) {
97 printf("Error reading from RTC\n");
98 return -EIO;
99 }
100
101 sec = rtc_read(RTC_SEC_REG_ADDR);
102 min = rtc_read(RTC_MIN_REG_ADDR);
103 hour = rtc_read(RTC_HR_REG_ADDR);
104 wday = rtc_read(RTC_DAY_REG_ADDR);
105 mday = rtc_read(RTC_DATE_REG_ADDR);
106 mon = rtc_read(RTC_MON_REG_ADDR);
107 year = rtc_read(RTC_YR_REG_ADDR);
108
109 DEBUGR("Get RTC year: %02x mon: %02x mday: %02x wday: %02x "
110 "hr: %02x min: %02x sec: %02x\n",
111 year, mon, mday, wday, hour, min, sec);
112
113 /* dump status */
114 ctl2 = rtc_read(RTC_CTL2_REG_ADDR);
115 if (ctl2 & RTC_CTL2_BIT_PON) {
116 printf("RTC: power-on detected\n");
117 rel = -1;
118 }
119
120 if (ctl2 & RTC_CTL2_BIT_VDET) {
121 printf("RTC: voltage drop detected\n");
122 rel = -1;
123 }
124 if (rx8025_is_osc_stopped(dev->driver_data, ctl2)) {
125 printf("RTC: oscillator stop detected\n");
126 rel = -1;
127 }
128
129 tmp->tm_sec = bcd2bin(sec & 0x7F);
130 tmp->tm_min = bcd2bin(min & 0x7F);
131 if (rtc_read(RTC_CTL1_REG_ADDR) & RTC_CTL1_BIT_2412)
132 tmp->tm_hour = bcd2bin(hour & 0x3F);
133 else
134 tmp->tm_hour = bcd2bin(hour & 0x1F) % 12 +
135 ((hour & 0x20) ? 12 : 0);
136
137 tmp->tm_mday = bcd2bin (mday & 0x3F);
138 tmp->tm_mon = bcd2bin (mon & 0x1F);
139 tmp->tm_year = bcd2bin (year) + ( bcd2bin (year) >= 70 ? 1900 : 2000);
140 tmp->tm_wday = bcd2bin (wday & 0x07);
141 tmp->tm_yday = 0;
142 tmp->tm_isdst= 0;
143
144 DEBUGR("Get DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
145 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
146 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
147
148 return rel;
149 }
150
151 /*
152 * Set the RTC
153 */
rx8025_rtc_set(struct udevice * dev,const struct rtc_time * tmp)154 static int rx8025_rtc_set(struct udevice *dev, const struct rtc_time *tmp)
155 {
156 /* To work around the read/write cycle issue mentioned
157 * at the top of this file, write all the time registers
158 * in one I2C transaction
159 */
160 u8 write_op[8];
161
162 /* 2412 flag must be set before doing a RTC write,
163 * otherwise the seconds and minute register
164 * will be cleared when the flag is set
165 */
166 if (rtc_write(dev, RTC_CTL1_REG_ADDR, RTC_CTL1_BIT_2412))
167 return -EIO;
168
169 DEBUGR("Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
170 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
171 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
172
173 if (tmp->tm_year < 1970 || tmp->tm_year > 2069)
174 printf("WARNING: year should be between 1970 and 2069!\n");
175
176 write_op[RTC_SEC_REG_ADDR] = bin2bcd(tmp->tm_sec);
177 write_op[RTC_MIN_REG_ADDR] = bin2bcd(tmp->tm_min);
178 write_op[RTC_HR_REG_ADDR] = bin2bcd(tmp->tm_hour);
179 write_op[RTC_DAY_REG_ADDR] = bin2bcd(tmp->tm_wday);
180 write_op[RTC_DATE_REG_ADDR] = bin2bcd(tmp->tm_mday);
181 write_op[RTC_MON_REG_ADDR] = bin2bcd(tmp->tm_mon);
182 write_op[RTC_YR_REG_ADDR] = bin2bcd(tmp->tm_year % 100);
183 write_op[RTC_OFFSET_REG_ADDR] = 0;
184
185 return dm_i2c_write(dev, 0, &write_op[0], 8);
186 }
187
188 /*
189 * Reset the RTC
190 */
rx8025_rtc_reset(struct udevice * dev)191 static int rx8025_rtc_reset(struct udevice *dev)
192 {
193 uchar buf[16];
194 uchar ctl2;
195
196 if (dm_i2c_read(dev, 0, buf, sizeof(buf))) {
197 printf("Error reading from RTC\n");
198 return -EIO;
199 }
200
201 ctl2 = rtc_read(RTC_CTL2_REG_ADDR);
202 ctl2 &= ~(RTC_CTL2_BIT_PON | RTC_CTL2_BIT_VDET);
203
204 if (dev->driver_data == model_rx_8035)
205 ctl2 &= ~(RTC_CTL2_BIT_XST);
206 else
207 ctl2 |= RTC_CTL2_BIT_XST;
208
209 return rtc_write(dev, RTC_CTL2_REG_ADDR, ctl2);
210 }
211
212 /*
213 * Helper functions
214 */
rtc_write(struct udevice * dev,uchar reg,uchar val)215 static int rtc_write(struct udevice *dev, uchar reg, uchar val)
216 {
217 /* The RX8025/RX8035 uses the top 4 bits of the
218 * 'offset' byte as the start register address,
219 * and the bottom 4 bits as a 'transfer' mode setting
220 * (only applicable for reads)
221 */
222 u8 offset = (reg << 4);
223
224 if (dm_i2c_reg_write(dev, offset, val)) {
225 printf("Error writing to RTC\n");
226 return -EIO;
227 }
228
229 return 0;
230 }
231
rx8025_probe(struct udevice * dev)232 static int rx8025_probe(struct udevice *dev)
233 {
234 uchar buf[16];
235 int ret = 0;
236
237 if (i2c_get_chip_offset_len(dev) != 1)
238 ret = i2c_set_chip_offset_len(dev, 1);
239
240 if (ret)
241 return ret;
242
243 return dm_i2c_read(dev, 0, buf, sizeof(buf));
244 }
245
246 static const struct rtc_ops rx8025_rtc_ops = {
247 .get = rx8025_rtc_get,
248 .set = rx8025_rtc_set,
249 .reset = rx8025_rtc_reset,
250 };
251
252 static const struct udevice_id rx8025_rtc_ids[] = {
253 { .compatible = "epson,rx8025", .data = model_rx_8025 },
254 { .compatible = "epson,rx8035", .data = model_rx_8035 },
255 { }
256 };
257
258 U_BOOT_DRIVER(rx8025_rtc) = {
259 .name = "rx8025_rtc",
260 .id = UCLASS_RTC,
261 .probe = rx8025_probe,
262 .of_match = rx8025_rtc_ids,
263 .ops = &rx8025_rtc_ops,
264 };
265