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d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
cce2da9a TH |
2 | /* drivers/rtc/rtc-rx4581.c |
3 | * | |
4 | * written by Torben Hohn <torbenh@linutronix.de> | |
5 | * | |
6 | * Based on: | |
7 | * drivers/rtc/rtc-max6902.c | |
8 | * | |
9 | * Copyright (C) 2006 8D Technologies inc. | |
10 | * Copyright (C) 2004 Compulab Ltd. | |
11 | * | |
cce2da9a TH |
12 | * Driver for MAX6902 spi RTC |
13 | * | |
14 | * and based on: | |
15 | * drivers/rtc/rtc-rx8581.c | |
16 | * | |
17 | * An I2C driver for the Epson RX8581 RTC | |
18 | * | |
19 | * Author: Martyn Welch <martyn.welch@ge.com> | |
20 | * Copyright 2008 GE Intelligent Platforms Embedded Systems, Inc. | |
21 | * | |
cce2da9a TH |
22 | * Based on: rtc-pcf8563.c (An I2C driver for the Philips PCF8563 RTC) |
23 | * Copyright 2005-06 Tower Technologies | |
cce2da9a TH |
24 | */ |
25 | ||
26 | #include <linux/module.h> | |
27 | #include <linux/kernel.h> | |
28 | #include <linux/platform_device.h> | |
29 | #include <linux/init.h> | |
30 | #include <linux/rtc.h> | |
31 | #include <linux/spi/spi.h> | |
32 | #include <linux/bcd.h> | |
33 | ||
34 | #define RX4581_REG_SC 0x00 /* Second in BCD */ | |
35 | #define RX4581_REG_MN 0x01 /* Minute in BCD */ | |
36 | #define RX4581_REG_HR 0x02 /* Hour in BCD */ | |
37 | #define RX4581_REG_DW 0x03 /* Day of Week */ | |
38 | #define RX4581_REG_DM 0x04 /* Day of Month in BCD */ | |
39 | #define RX4581_REG_MO 0x05 /* Month in BCD */ | |
40 | #define RX4581_REG_YR 0x06 /* Year in BCD */ | |
41 | #define RX4581_REG_RAM 0x07 /* RAM */ | |
42 | #define RX4581_REG_AMN 0x08 /* Alarm Min in BCD*/ | |
43 | #define RX4581_REG_AHR 0x09 /* Alarm Hour in BCD */ | |
44 | #define RX4581_REG_ADM 0x0A | |
45 | #define RX4581_REG_ADW 0x0A | |
46 | #define RX4581_REG_TMR0 0x0B | |
47 | #define RX4581_REG_TMR1 0x0C | |
48 | #define RX4581_REG_EXT 0x0D /* Extension Register */ | |
49 | #define RX4581_REG_FLAG 0x0E /* Flag Register */ | |
50 | #define RX4581_REG_CTRL 0x0F /* Control Register */ | |
51 | ||
52 | ||
53 | /* Flag Register bit definitions */ | |
54 | #define RX4581_FLAG_UF 0x20 /* Update */ | |
55 | #define RX4581_FLAG_TF 0x10 /* Timer */ | |
56 | #define RX4581_FLAG_AF 0x08 /* Alarm */ | |
57 | #define RX4581_FLAG_VLF 0x02 /* Voltage Low */ | |
58 | ||
59 | /* Control Register bit definitions */ | |
60 | #define RX4581_CTRL_UIE 0x20 /* Update Interrupt Enable */ | |
61 | #define RX4581_CTRL_TIE 0x10 /* Timer Interrupt Enable */ | |
62 | #define RX4581_CTRL_AIE 0x08 /* Alarm Interrupt Enable */ | |
63 | #define RX4581_CTRL_STOP 0x02 /* STOP bit */ | |
64 | #define RX4581_CTRL_RESET 0x01 /* RESET bit */ | |
65 | ||
66 | static int rx4581_set_reg(struct device *dev, unsigned char address, | |
67 | unsigned char data) | |
68 | { | |
69 | struct spi_device *spi = to_spi_device(dev); | |
70 | unsigned char buf[2]; | |
71 | ||
72 | /* high nibble must be '0' to write */ | |
73 | buf[0] = address & 0x0f; | |
74 | buf[1] = data; | |
75 | ||
76 | return spi_write_then_read(spi, buf, 2, NULL, 0); | |
77 | } | |
78 | ||
79 | static int rx4581_get_reg(struct device *dev, unsigned char address, | |
80 | unsigned char *data) | |
81 | { | |
82 | struct spi_device *spi = to_spi_device(dev); | |
83 | ||
84 | /* Set MSB to indicate read */ | |
85 | *data = address | 0x80; | |
86 | ||
87 | return spi_write_then_read(spi, data, 1, data, 1); | |
88 | } | |
89 | ||
90 | /* | |
91 | * In the routines that deal directly with the rx8581 hardware, we use | |
92 | * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch. | |
93 | */ | |
94 | static int rx4581_get_datetime(struct device *dev, struct rtc_time *tm) | |
95 | { | |
96 | struct spi_device *spi = to_spi_device(dev); | |
97 | unsigned char date[7]; | |
98 | unsigned char data; | |
99 | int err; | |
100 | ||
101 | /* First we ensure that the "update flag" is not set, we read the | |
102 | * time and date then re-read the "update flag". If the update flag | |
103 | * has been set, we know that the time has changed during the read so | |
104 | * we repeat the whole process again. | |
105 | */ | |
106 | err = rx4581_get_reg(dev, RX4581_REG_FLAG, &data); | |
107 | if (err != 0) { | |
108 | dev_err(dev, "Unable to read device flags\n"); | |
109 | return -EIO; | |
110 | } | |
111 | ||
112 | do { | |
113 | /* If update flag set, clear it */ | |
114 | if (data & RX4581_FLAG_UF) { | |
115 | err = rx4581_set_reg(dev, | |
116 | RX4581_REG_FLAG, (data & ~RX4581_FLAG_UF)); | |
117 | if (err != 0) { | |
118 | dev_err(dev, "Unable to write device " | |
119 | "flags\n"); | |
120 | return -EIO; | |
121 | } | |
122 | } | |
123 | ||
124 | /* Now read time and date */ | |
125 | date[0] = 0x80; | |
126 | err = spi_write_then_read(spi, date, 1, date, 7); | |
127 | if (err < 0) { | |
128 | dev_err(dev, "Unable to read date\n"); | |
129 | return -EIO; | |
130 | } | |
131 | ||
132 | /* Check flag register */ | |
133 | err = rx4581_get_reg(dev, RX4581_REG_FLAG, &data); | |
134 | if (err != 0) { | |
135 | dev_err(dev, "Unable to read device flags\n"); | |
136 | return -EIO; | |
137 | } | |
138 | } while (data & RX4581_FLAG_UF); | |
139 | ||
140 | if (data & RX4581_FLAG_VLF) | |
141 | dev_info(dev, | |
142 | "low voltage detected, date/time is not reliable.\n"); | |
143 | ||
144 | dev_dbg(dev, | |
145 | "%s: raw data is sec=%02x, min=%02x, hr=%02x, " | |
146 | "wday=%02x, mday=%02x, mon=%02x, year=%02x\n", | |
147 | __func__, | |
148 | date[0], date[1], date[2], date[3], date[4], date[5], date[6]); | |
149 | ||
150 | tm->tm_sec = bcd2bin(date[RX4581_REG_SC] & 0x7F); | |
151 | tm->tm_min = bcd2bin(date[RX4581_REG_MN] & 0x7F); | |
152 | tm->tm_hour = bcd2bin(date[RX4581_REG_HR] & 0x3F); /* rtc hr 0-23 */ | |
153 | tm->tm_wday = ilog2(date[RX4581_REG_DW] & 0x7F); | |
154 | tm->tm_mday = bcd2bin(date[RX4581_REG_DM] & 0x3F); | |
155 | tm->tm_mon = bcd2bin(date[RX4581_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */ | |
156 | tm->tm_year = bcd2bin(date[RX4581_REG_YR]); | |
157 | if (tm->tm_year < 70) | |
158 | tm->tm_year += 100; /* assume we are in 1970...2069 */ | |
159 | ||
160 | ||
161 | dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, " | |
162 | "mday=%d, mon=%d, year=%d, wday=%d\n", | |
163 | __func__, | |
164 | tm->tm_sec, tm->tm_min, tm->tm_hour, | |
165 | tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); | |
166 | ||
02d28997 | 167 | return 0; |
cce2da9a TH |
168 | } |
169 | ||
170 | static int rx4581_set_datetime(struct device *dev, struct rtc_time *tm) | |
171 | { | |
172 | struct spi_device *spi = to_spi_device(dev); | |
173 | int err; | |
174 | unsigned char buf[8], data; | |
175 | ||
176 | dev_dbg(dev, "%s: secs=%d, mins=%d, hours=%d, " | |
177 | "mday=%d, mon=%d, year=%d, wday=%d\n", | |
178 | __func__, | |
179 | tm->tm_sec, tm->tm_min, tm->tm_hour, | |
180 | tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); | |
181 | ||
182 | buf[0] = 0x00; | |
183 | /* hours, minutes and seconds */ | |
184 | buf[RX4581_REG_SC+1] = bin2bcd(tm->tm_sec); | |
185 | buf[RX4581_REG_MN+1] = bin2bcd(tm->tm_min); | |
186 | buf[RX4581_REG_HR+1] = bin2bcd(tm->tm_hour); | |
187 | ||
188 | buf[RX4581_REG_DM+1] = bin2bcd(tm->tm_mday); | |
189 | ||
190 | /* month, 1 - 12 */ | |
191 | buf[RX4581_REG_MO+1] = bin2bcd(tm->tm_mon + 1); | |
192 | ||
193 | /* year and century */ | |
194 | buf[RX4581_REG_YR+1] = bin2bcd(tm->tm_year % 100); | |
195 | buf[RX4581_REG_DW+1] = (0x1 << tm->tm_wday); | |
196 | ||
197 | /* Stop the clock */ | |
198 | err = rx4581_get_reg(dev, RX4581_REG_CTRL, &data); | |
199 | if (err != 0) { | |
200 | dev_err(dev, "Unable to read control register\n"); | |
201 | return -EIO; | |
202 | } | |
203 | ||
204 | err = rx4581_set_reg(dev, RX4581_REG_CTRL, | |
205 | (data | RX4581_CTRL_STOP)); | |
206 | if (err != 0) { | |
207 | dev_err(dev, "Unable to write control register\n"); | |
208 | return -EIO; | |
209 | } | |
210 | ||
211 | /* write register's data */ | |
212 | err = spi_write_then_read(spi, buf, 8, NULL, 0); | |
213 | if (err != 0) { | |
214 | dev_err(dev, "Unable to write to date registers\n"); | |
215 | return -EIO; | |
216 | } | |
217 | ||
218 | /* get VLF and clear it */ | |
219 | err = rx4581_get_reg(dev, RX4581_REG_FLAG, &data); | |
220 | if (err != 0) { | |
221 | dev_err(dev, "Unable to read flag register\n"); | |
222 | return -EIO; | |
223 | } | |
224 | ||
225 | err = rx4581_set_reg(dev, RX4581_REG_FLAG, | |
226 | (data & ~(RX4581_FLAG_VLF))); | |
227 | if (err != 0) { | |
228 | dev_err(dev, "Unable to write flag register\n"); | |
229 | return -EIO; | |
230 | } | |
231 | ||
232 | /* Restart the clock */ | |
233 | err = rx4581_get_reg(dev, RX4581_REG_CTRL, &data); | |
234 | if (err != 0) { | |
235 | dev_err(dev, "Unable to read control register\n"); | |
236 | return -EIO; | |
237 | } | |
238 | ||
239 | err = rx4581_set_reg(dev, RX4581_REG_CTRL, | |
240 | (data & ~(RX4581_CTRL_STOP))); | |
241 | if (err != 0) { | |
242 | dev_err(dev, "Unable to write control register\n"); | |
243 | return -EIO; | |
244 | } | |
245 | ||
246 | return 0; | |
247 | } | |
248 | ||
249 | static const struct rtc_class_ops rx4581_rtc_ops = { | |
250 | .read_time = rx4581_get_datetime, | |
251 | .set_time = rx4581_set_datetime, | |
252 | }; | |
253 | ||
254 | static int rx4581_probe(struct spi_device *spi) | |
255 | { | |
256 | struct rtc_device *rtc; | |
257 | unsigned char tmp; | |
258 | int res; | |
259 | ||
260 | res = rx4581_get_reg(&spi->dev, RX4581_REG_SC, &tmp); | |
261 | if (res != 0) | |
262 | return res; | |
263 | ||
92bb34ca JH |
264 | rtc = devm_rtc_device_register(&spi->dev, "rx4581", |
265 | &rx4581_rtc_ops, THIS_MODULE); | |
cce2da9a TH |
266 | if (IS_ERR(rtc)) |
267 | return PTR_ERR(rtc); | |
268 | ||
bb49a3a7 | 269 | spi_set_drvdata(spi, rtc); |
cce2da9a TH |
270 | return 0; |
271 | } | |
272 | ||
cce2da9a TH |
273 | static const struct spi_device_id rx4581_id[] = { |
274 | { "rx4581", 0 }, | |
275 | { } | |
276 | }; | |
277 | MODULE_DEVICE_TABLE(spi, rx4581_id); | |
278 | ||
279 | static struct spi_driver rx4581_driver = { | |
280 | .driver = { | |
281 | .name = "rtc-rx4581", | |
cce2da9a TH |
282 | }, |
283 | .probe = rx4581_probe, | |
cce2da9a TH |
284 | .id_table = rx4581_id, |
285 | }; | |
286 | ||
287 | module_spi_driver(rx4581_driver); | |
288 | ||
289 | MODULE_DESCRIPTION("rx4581 spi RTC driver"); | |
290 | MODULE_AUTHOR("Torben Hohn"); | |
291 | MODULE_LICENSE("GPL"); | |
292 | MODULE_ALIAS("spi:rtc-rx4581"); |