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f6009157 | 1 | /* rtc-ds3234.c |
2f9b75e0 DA |
2 | * |
3 | * Driver for Dallas Semiconductor (DS3234) SPI RTC with Integrated Crystal | |
4 | * and SRAM. | |
5 | * | |
6 | * Copyright (C) 2008 MIMOMax Wireless Ltd. | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License version 2 as | |
10 | * published by the Free Software Foundation. | |
11 | * | |
2f9b75e0 DA |
12 | */ |
13 | ||
f6009157 AZ |
14 | #include <linux/init.h> |
15 | #include <linux/module.h> | |
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16 | #include <linux/device.h> |
17 | #include <linux/platform_device.h> | |
18 | #include <linux/rtc.h> | |
19 | #include <linux/spi/spi.h> | |
20 | #include <linux/bcd.h> | |
21 | ||
22 | #define DS3234_REG_SECONDS 0x00 | |
23 | #define DS3234_REG_MINUTES 0x01 | |
24 | #define DS3234_REG_HOURS 0x02 | |
25 | #define DS3234_REG_DAY 0x03 | |
26 | #define DS3234_REG_DATE 0x04 | |
27 | #define DS3234_REG_MONTH 0x05 | |
28 | #define DS3234_REG_YEAR 0x06 | |
29 | #define DS3234_REG_CENTURY (1 << 7) /* Bit 7 of the Month register */ | |
30 | ||
31 | #define DS3234_REG_CONTROL 0x0E | |
32 | #define DS3234_REG_CONT_STAT 0x0F | |
33 | ||
f6009157 | 34 | static int ds3234_set_reg(struct device *dev, unsigned char address, |
2f9b75e0 DA |
35 | unsigned char data) |
36 | { | |
37 | struct spi_device *spi = to_spi_device(dev); | |
38 | unsigned char buf[2]; | |
39 | ||
40 | /* MSB must be '1' to indicate write */ | |
41 | buf[0] = address | 0x80; | |
42 | buf[1] = data; | |
43 | ||
f6009157 | 44 | return spi_write_then_read(spi, buf, 2, NULL, 0); |
2f9b75e0 DA |
45 | } |
46 | ||
47 | static int ds3234_get_reg(struct device *dev, unsigned char address, | |
48 | unsigned char *data) | |
49 | { | |
50 | struct spi_device *spi = to_spi_device(dev); | |
2f9b75e0 | 51 | |
f6009157 | 52 | *data = address & 0x7f; |
2f9b75e0 | 53 | |
f6009157 | 54 | return spi_write_then_read(spi, data, 1, data, 1); |
2f9b75e0 DA |
55 | } |
56 | ||
f6009157 | 57 | static int ds3234_read_time(struct device *dev, struct rtc_time *dt) |
2f9b75e0 | 58 | { |
f6009157 AZ |
59 | int err; |
60 | unsigned char buf[8]; | |
2f9b75e0 | 61 | struct spi_device *spi = to_spi_device(dev); |
2f9b75e0 | 62 | |
f6009157 | 63 | buf[0] = 0x00; /* Start address */ |
2f9b75e0 | 64 | |
f6009157 AZ |
65 | err = spi_write_then_read(spi, buf, 1, buf, 8); |
66 | if (err != 0) | |
67 | return err; | |
68 | ||
69 | /* Seconds, Minutes, Hours, Day, Date, Month, Year */ | |
70 | dt->tm_sec = bcd2bin(buf[0]); | |
71 | dt->tm_min = bcd2bin(buf[1]); | |
72 | dt->tm_hour = bcd2bin(buf[2] & 0x3f); | |
73 | dt->tm_wday = bcd2bin(buf[3]) - 1; /* 0 = Sun */ | |
74 | dt->tm_mday = bcd2bin(buf[4]); | |
75 | dt->tm_mon = bcd2bin(buf[5] & 0x1f) - 1; /* 0 = Jan */ | |
97dd8969 | 76 | dt->tm_year = bcd2bin(buf[6] & 0xff) + 100; /* Assume 20YY */ |
f6009157 AZ |
77 | |
78 | return rtc_valid_tm(dt); | |
2f9b75e0 DA |
79 | } |
80 | ||
f6009157 | 81 | static int ds3234_set_time(struct device *dev, struct rtc_time *dt) |
2f9b75e0 | 82 | { |
2f9b75e0 DA |
83 | ds3234_set_reg(dev, DS3234_REG_SECONDS, bin2bcd(dt->tm_sec)); |
84 | ds3234_set_reg(dev, DS3234_REG_MINUTES, bin2bcd(dt->tm_min)); | |
85 | ds3234_set_reg(dev, DS3234_REG_HOURS, bin2bcd(dt->tm_hour) & 0x3f); | |
86 | ||
87 | /* 0 = Sun */ | |
88 | ds3234_set_reg(dev, DS3234_REG_DAY, bin2bcd(dt->tm_wday + 1)); | |
89 | ds3234_set_reg(dev, DS3234_REG_DATE, bin2bcd(dt->tm_mday)); | |
90 | ||
91 | /* 0 = Jan */ | |
92 | ds3234_set_reg(dev, DS3234_REG_MONTH, bin2bcd(dt->tm_mon + 1)); | |
93 | ||
94 | /* Assume 20YY although we just want to make sure not to go negative. */ | |
95 | if (dt->tm_year > 100) | |
96 | dt->tm_year -= 100; | |
97 | ||
98 | ds3234_set_reg(dev, DS3234_REG_YEAR, bin2bcd(dt->tm_year)); | |
99 | ||
100 | return 0; | |
101 | } | |
102 | ||
2f9b75e0 DA |
103 | static const struct rtc_class_ops ds3234_rtc_ops = { |
104 | .read_time = ds3234_read_time, | |
105 | .set_time = ds3234_set_time, | |
106 | }; | |
107 | ||
5a167f45 | 108 | static int ds3234_probe(struct spi_device *spi) |
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109 | { |
110 | struct rtc_device *rtc; | |
111 | unsigned char tmp; | |
2f9b75e0 DA |
112 | int res; |
113 | ||
2f9b75e0 DA |
114 | spi->mode = SPI_MODE_3; |
115 | spi->bits_per_word = 8; | |
116 | spi_setup(spi); | |
117 | ||
2f9b75e0 | 118 | res = ds3234_get_reg(&spi->dev, DS3234_REG_SECONDS, &tmp); |
f6009157 | 119 | if (res != 0) |
2f9b75e0 | 120 | return res; |
2f9b75e0 DA |
121 | |
122 | /* Control settings | |
123 | * | |
124 | * CONTROL_REG | |
125 | * BIT 7 6 5 4 3 2 1 0 | |
126 | * EOSC BBSQW CONV RS2 RS1 INTCN A2IE A1IE | |
127 | * | |
128 | * 0 0 0 1 1 1 0 0 | |
129 | * | |
130 | * CONTROL_STAT_REG | |
131 | * BIT 7 6 5 4 3 2 1 0 | |
132 | * OSF BB32kHz CRATE1 CRATE0 EN32kHz BSY A2F A1F | |
133 | * | |
134 | * 1 0 0 0 1 0 0 0 | |
135 | */ | |
136 | ds3234_get_reg(&spi->dev, DS3234_REG_CONTROL, &tmp); | |
137 | ds3234_set_reg(&spi->dev, DS3234_REG_CONTROL, tmp & 0x1c); | |
138 | ||
139 | ds3234_get_reg(&spi->dev, DS3234_REG_CONT_STAT, &tmp); | |
140 | ds3234_set_reg(&spi->dev, DS3234_REG_CONT_STAT, tmp & 0x88); | |
141 | ||
142 | /* Print our settings */ | |
143 | ds3234_get_reg(&spi->dev, DS3234_REG_CONTROL, &tmp); | |
144 | dev_info(&spi->dev, "Control Reg: 0x%02x\n", tmp); | |
145 | ||
146 | ds3234_get_reg(&spi->dev, DS3234_REG_CONT_STAT, &tmp); | |
147 | dev_info(&spi->dev, "Ctrl/Stat Reg: 0x%02x\n", tmp); | |
148 | ||
2c0011dd JH |
149 | rtc = devm_rtc_device_register(&spi->dev, "ds3234", |
150 | &ds3234_rtc_ops, THIS_MODULE); | |
f6009157 AZ |
151 | if (IS_ERR(rtc)) |
152 | return PTR_ERR(rtc); | |
153 | ||
3cf79005 | 154 | spi_set_drvdata(spi, rtc); |
f6009157 | 155 | |
2f9b75e0 DA |
156 | return 0; |
157 | } | |
158 | ||
2f9b75e0 DA |
159 | static struct spi_driver ds3234_driver = { |
160 | .driver = { | |
161 | .name = "ds3234", | |
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162 | }, |
163 | .probe = ds3234_probe, | |
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164 | }; |
165 | ||
109e9418 | 166 | module_spi_driver(ds3234_driver); |
2f9b75e0 DA |
167 | |
168 | MODULE_DESCRIPTION("DS3234 SPI RTC driver"); | |
169 | MODULE_AUTHOR("Dennis Aberilla <denzzzhome@yahoo.com>"); | |
170 | MODULE_LICENSE("GPL"); | |
e0626e38 | 171 | MODULE_ALIAS("spi:ds3234"); |