1 | // SPDX-License-Identifier: GPL-2.0-only |
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 | * |
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 | * |
22 | * Based on: rtc-pcf8563.c (An I2C driver for the Philips PCF8563 RTC) |
23 | * Copyright 2005-06 Tower Technologies |
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, txbuf: buf, n_tx: 2, NULL, n_rx: 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, txbuf: data, n_tx: 1, rxbuf: data, n_rx: 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: &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: (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, txbuf: date, n_tx: 1, rxbuf: date, n_rx: 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: &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 | |
167 | return 0; |
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: &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: (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, txbuf: buf, n_tx: 8, NULL, n_rx: 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: &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: (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: &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: (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(dev: &spi->dev, RX4581_REG_SC, data: &tmp); |
261 | if (res != 0) |
262 | return res; |
263 | |
264 | rtc = devm_rtc_device_register(dev: &spi->dev, name: "rx4581" , |
265 | ops: &rx4581_rtc_ops, THIS_MODULE); |
266 | if (IS_ERR(ptr: rtc)) |
267 | return PTR_ERR(ptr: rtc); |
268 | |
269 | spi_set_drvdata(spi, data: rtc); |
270 | return 0; |
271 | } |
272 | |
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" , |
282 | }, |
283 | .probe = rx4581_probe, |
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" ); |
293 | |