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2805b969 MD |
1 | /* drivers/rtc/rtc-r9701.c |
2 | * | |
3 | * Driver for Epson RTC-9701JE | |
4 | * | |
5 | * Copyright (C) 2008 Magnus Damm | |
6 | * | |
7 | * Based on drivers/rtc/rtc-max6902.c | |
8 | * | |
9 | * Copyright (C) 2006 8D Technologies inc. | |
10 | * Copyright (C) 2004 Compulab Ltd. | |
11 | * | |
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. | |
15 | */ | |
16 | ||
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> | |
28 | ||
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 */ | |
44 | ||
45 | static int write_reg(struct device *dev, int address, unsigned char data) | |
46 | { | |
47 | struct spi_device *spi = to_spi_device(dev); | |
48 | unsigned char buf[2]; | |
49 | ||
50 | buf[0] = address & 0x7f; | |
51 | buf[1] = data; | |
52 | ||
53 | return spi_write(spi, buf, ARRAY_SIZE(buf)); | |
54 | } | |
55 | ||
56 | static int read_regs(struct device *dev, unsigned char *regs, int no_regs) | |
57 | { | |
58 | struct spi_device *spi = to_spi_device(dev); | |
59 | u8 txbuf[1], rxbuf[1]; | |
60 | int k, ret; | |
61 | ||
62 | ret = 0; | |
63 | ||
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); | |
67 | regs[k] = rxbuf[0]; | |
68 | } | |
69 | ||
70 | return ret; | |
71 | } | |
72 | ||
73 | static int r9701_get_datetime(struct device *dev, struct rtc_time *dt) | |
74 | { | |
75 | struct spi_device *spi = to_spi_device(dev); | |
76 | unsigned long time; | |
77 | int ret; | |
78 | unsigned char buf[] = { RSECCNT, RMINCNT, RHRCNT, | |
79 | RDAYCNT, RMONCNT, RYRCNT }; | |
80 | ||
81 | ret = read_regs(&spi->dev, buf, ARRAY_SIZE(buf)); | |
82 | if (ret) | |
83 | return ret; | |
84 | ||
85 | memset(dt, 0, sizeof(*dt)); | |
86 | ||
87 | dt->tm_sec = BCD2BIN(buf[0]); /* RSECCNT */ | |
88 | dt->tm_min = BCD2BIN(buf[1]); /* RMINCNT */ | |
89 | dt->tm_hour = BCD2BIN(buf[2]); /* RHRCNT */ | |
90 | ||
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 */ | |
94 | ||
95 | /* the rtc device may contain illegal values on power up | |
96 | * according to the data sheet. make sure they are valid. | |
97 | */ | |
98 | ||
99 | ret = rtc_valid_tm(dt); | |
100 | if (ret) | |
101 | return ret; | |
102 | ||
103 | /* don't bother with yday, wday and isdst. | |
104 | * let the rtc core calculate them for us. | |
105 | */ | |
106 | ||
107 | rtc_tm_to_time(dt, &time); | |
108 | rtc_time_to_tm(time, dt); | |
109 | return 0; | |
110 | } | |
111 | ||
112 | static int r9701_set_datetime(struct device *dev, struct rtc_time *dt) | |
113 | { | |
114 | int ret, year; | |
115 | ||
116 | year = dt->tm_year + 1900; | |
117 | if (year >= 2100 || year < 2000) | |
118 | return -EINVAL; | |
119 | ||
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); | |
127 | ||
128 | return ret; | |
129 | } | |
130 | ||
131 | static const struct rtc_class_ops r9701_rtc_ops = { | |
132 | .read_time = r9701_get_datetime, | |
133 | .set_time = r9701_set_datetime, | |
134 | }; | |
135 | ||
136 | static int __devinit r9701_probe(struct spi_device *spi) | |
137 | { | |
138 | struct rtc_device *rtc; | |
139 | unsigned char tmp; | |
140 | int res; | |
141 | ||
142 | rtc = rtc_device_register("r9701", | |
143 | &spi->dev, &r9701_rtc_ops, THIS_MODULE); | |
144 | if (IS_ERR(rtc)) | |
145 | return PTR_ERR(rtc); | |
146 | ||
147 | dev_set_drvdata(&spi->dev, rtc); | |
148 | ||
149 | spi->mode = SPI_MODE_3; | |
150 | spi->bits_per_word = 8; | |
151 | spi_setup(spi); | |
152 | ||
153 | tmp = R100CNT; | |
154 | res = read_regs(&spi->dev, &tmp, 1); | |
155 | if (res || tmp != 0x20) { | |
156 | rtc_device_unregister(rtc); | |
157 | return res; | |
158 | } | |
159 | ||
160 | return 0; | |
161 | } | |
162 | ||
163 | static int __devexit r9701_remove(struct spi_device *spi) | |
164 | { | |
165 | struct rtc_device *rtc = dev_get_drvdata(&spi->dev); | |
166 | ||
167 | rtc_device_unregister(rtc); | |
168 | return 0; | |
169 | } | |
170 | ||
171 | static struct spi_driver r9701_driver = { | |
172 | .driver = { | |
173 | .name = "rtc-r9701", | |
174 | .bus = &spi_bus_type, | |
175 | .owner = THIS_MODULE, | |
176 | }, | |
177 | .probe = r9701_probe, | |
178 | .remove = __devexit_p(r9701_remove), | |
179 | }; | |
180 | ||
181 | static __init int r9701_init(void) | |
182 | { | |
183 | return spi_register_driver(&r9701_driver); | |
184 | } | |
185 | module_init(r9701_init); | |
186 | ||
187 | static __exit void r9701_exit(void) | |
188 | { | |
189 | spi_unregister_driver(&r9701_driver); | |
190 | } | |
191 | module_exit(r9701_exit); | |
192 | ||
193 | MODULE_DESCRIPTION("r9701 spi RTC driver"); | |
194 | MODULE_AUTHOR("Magnus Damm <damm@opensource.se>"); | |
195 | MODULE_LICENSE("GPL"); |