1 /* drivers/rtc/rtc-r9701.c
3 * Driver for Epson RTC-9701JE
5 * Copyright (C) 2008 Magnus Damm
7 * Based on drivers/rtc/rtc-max6902.c
9 * Copyright (C) 2006 8D Technologies inc.
10 * Copyright (C) 2004 Compulab Ltd.
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License version 2 as
14 * published by the Free Software Foundation.
17 #include <linux/module.h>
18 #include <linux/version.h>
19 #include <linux/kernel.h>
20 #include <linux/platform_device.h>
21 #include <linux/device.h>
22 #include <linux/init.h>
23 #include <linux/rtc.h>
24 #include <linux/spi/spi.h>
25 #include <linux/bcd.h>
26 #include <linux/delay.h>
27 #include <linux/bitops.h>
29 #define RSECCNT 0x00 /* Second Counter */
30 #define RMINCNT 0x01 /* Minute Counter */
31 #define RHRCNT 0x02 /* Hour Counter */
32 #define RWKCNT 0x03 /* Week Counter */
33 #define RDAYCNT 0x04 /* Day Counter */
34 #define RMONCNT 0x05 /* Month Counter */
35 #define RYRCNT 0x06 /* Year Counter */
36 #define R100CNT 0x07 /* Y100 Counter */
37 #define RMINAR 0x08 /* Minute Alarm */
38 #define RHRAR 0x09 /* Hour Alarm */
39 #define RWKAR 0x0a /* Week/Day Alarm */
40 #define RTIMCNT 0x0c /* Interval Timer */
41 #define REXT 0x0d /* Extension Register */
42 #define RFLAG 0x0e /* RTC Flag Register */
43 #define RCR 0x0f /* RTC Control Register */
45 static int write_reg(struct device *dev, int address, unsigned char data)
47 struct spi_device *spi = to_spi_device(dev);
50 buf[0] = address & 0x7f;
53 return spi_write(spi, buf, ARRAY_SIZE(buf));
56 static int read_regs(struct device *dev, unsigned char *regs, int no_regs)
58 struct spi_device *spi = to_spi_device(dev);
59 u8 txbuf[1], rxbuf[1];
64 for (k = 0; ret == 0 && k < no_regs; k++) {
65 txbuf[0] = 0x80 | regs[k];
66 ret = spi_write_then_read(spi, txbuf, 1, rxbuf, 1);
73 static int r9701_get_datetime(struct device *dev, struct rtc_time *dt)
75 struct spi_device *spi = to_spi_device(dev);
78 unsigned char buf[] = { RSECCNT, RMINCNT, RHRCNT,
79 RDAYCNT, RMONCNT, RYRCNT };
81 ret = read_regs(&spi->dev, buf, ARRAY_SIZE(buf));
85 memset(dt, 0, sizeof(*dt));
87 dt->tm_sec = BCD2BIN(buf[0]); /* RSECCNT */
88 dt->tm_min = BCD2BIN(buf[1]); /* RMINCNT */
89 dt->tm_hour = BCD2BIN(buf[2]); /* RHRCNT */
91 dt->tm_mday = BCD2BIN(buf[3]); /* RDAYCNT */
92 dt->tm_mon = BCD2BIN(buf[4]) - 1; /* RMONCNT */
93 dt->tm_year = BCD2BIN(buf[5]) + 100; /* RYRCNT */
95 /* the rtc device may contain illegal values on power up
96 * according to the data sheet. make sure they are valid.
99 ret = rtc_valid_tm(dt);
103 /* don't bother with yday, wday and isdst.
104 * let the rtc core calculate them for us.
107 rtc_tm_to_time(dt, &time);
108 rtc_time_to_tm(time, dt);
112 static int r9701_set_datetime(struct device *dev, struct rtc_time *dt)
116 year = dt->tm_year + 1900;
117 if (year >= 2100 || year < 2000)
120 ret = write_reg(dev, RHRCNT, BIN2BCD(dt->tm_hour));
121 ret |= write_reg(dev, RMINCNT, BIN2BCD(dt->tm_min));
122 ret |= write_reg(dev, RSECCNT, BIN2BCD(dt->tm_sec));
123 ret |= write_reg(dev, RDAYCNT, BIN2BCD(dt->tm_mday));
124 ret |= write_reg(dev, RMONCNT, BIN2BCD(dt->tm_mon + 1));
125 ret |= write_reg(dev, RYRCNT, BIN2BCD(dt->tm_year - 100));
126 ret |= write_reg(dev, RWKCNT, 1 << dt->tm_wday);
131 static const struct rtc_class_ops r9701_rtc_ops = {
132 .read_time = r9701_get_datetime,
133 .set_time = r9701_set_datetime,
136 static int __devinit r9701_probe(struct spi_device *spi)
138 struct rtc_device *rtc;
142 rtc = rtc_device_register("r9701",
143 &spi->dev, &r9701_rtc_ops, THIS_MODULE);
147 dev_set_drvdata(&spi->dev, rtc);
149 spi->mode = SPI_MODE_3;
150 spi->bits_per_word = 8;
154 res = read_regs(&spi->dev, &tmp, 1);
155 if (res || tmp != 0x20) {
156 rtc_device_unregister(rtc);
163 static int __devexit r9701_remove(struct spi_device *spi)
165 struct rtc_device *rtc = dev_get_drvdata(&spi->dev);
167 rtc_device_unregister(rtc);
171 static struct spi_driver r9701_driver = {
174 .bus = &spi_bus_type,
175 .owner = THIS_MODULE,
177 .probe = r9701_probe,
178 .remove = __devexit_p(r9701_remove),
181 static __init int r9701_init(void)
183 return spi_register_driver(&r9701_driver);
185 module_init(r9701_init);
187 static __exit void r9701_exit(void)
189 spi_unregister_driver(&r9701_driver);
191 module_exit(r9701_exit);
193 MODULE_DESCRIPTION("r9701 spi RTC driver");
194 MODULE_AUTHOR("Magnus Damm <damm@opensource.se>");
195 MODULE_LICENSE("GPL");