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1 | /* rtc-ds1347.c |
2 | * | |
3 | * Driver for Dallas Semiconductor DS1347 Low Current, SPI Compatible | |
4 | * Real Time Clock | |
5 | * | |
6 | * Author : Raghavendra Chandra Ganiga <ravi23ganiga@gmail.com> | |
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 | * | |
12 | */ | |
13 | ||
14 | #include <linux/init.h> | |
15 | #include <linux/module.h> | |
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> | |
ee85bb5b | 21 | #include <linux/regmap.h> |
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22 | |
23 | /* Registers in ds1347 rtc */ | |
24 | ||
25 | #define DS1347_SECONDS_REG 0x01 | |
26 | #define DS1347_MINUTES_REG 0x03 | |
27 | #define DS1347_HOURS_REG 0x05 | |
28 | #define DS1347_DATE_REG 0x07 | |
29 | #define DS1347_MONTH_REG 0x09 | |
30 | #define DS1347_DAY_REG 0x0B | |
31 | #define DS1347_YEAR_REG 0x0D | |
32 | #define DS1347_CONTROL_REG 0x0F | |
33 | #define DS1347_STATUS_REG 0x17 | |
34 | #define DS1347_CLOCK_BURST 0x3F | |
35 | ||
ee85bb5b RG |
36 | static const struct regmap_range ds1347_ranges[] = { |
37 | { | |
38 | .range_min = DS1347_SECONDS_REG, | |
39 | .range_max = DS1347_STATUS_REG, | |
40 | }, | |
41 | }; | |
617b26a0 | 42 | |
ee85bb5b RG |
43 | static const struct regmap_access_table ds1347_access_table = { |
44 | .yes_ranges = ds1347_ranges, | |
45 | .n_yes_ranges = ARRAY_SIZE(ds1347_ranges), | |
46 | }; | |
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47 | |
48 | static int ds1347_read_time(struct device *dev, struct rtc_time *dt) | |
49 | { | |
50 | struct spi_device *spi = to_spi_device(dev); | |
ee85bb5b | 51 | struct regmap *map; |
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52 | int err; |
53 | unsigned char buf[8]; | |
54 | ||
ee85bb5b | 55 | map = spi_get_drvdata(spi); |
617b26a0 | 56 | |
ee85bb5b | 57 | err = regmap_bulk_read(map, DS1347_CLOCK_BURST, buf, 8); |
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58 | if (err) |
59 | return err; | |
60 | ||
61 | dt->tm_sec = bcd2bin(buf[0]); | |
62 | dt->tm_min = bcd2bin(buf[1]); | |
63 | dt->tm_hour = bcd2bin(buf[2] & 0x3F); | |
64 | dt->tm_mday = bcd2bin(buf[3]); | |
65 | dt->tm_mon = bcd2bin(buf[4]) - 1; | |
66 | dt->tm_wday = bcd2bin(buf[5]) - 1; | |
67 | dt->tm_year = bcd2bin(buf[6]) + 100; | |
68 | ||
69 | return rtc_valid_tm(dt); | |
70 | } | |
71 | ||
72 | static int ds1347_set_time(struct device *dev, struct rtc_time *dt) | |
73 | { | |
74 | struct spi_device *spi = to_spi_device(dev); | |
ee85bb5b RG |
75 | struct regmap *map; |
76 | unsigned char buf[8]; | |
77 | ||
78 | map = spi_get_drvdata(spi); | |
617b26a0 | 79 | |
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80 | buf[0] = bin2bcd(dt->tm_sec); |
81 | buf[1] = bin2bcd(dt->tm_min); | |
82 | buf[2] = (bin2bcd(dt->tm_hour) & 0x3F); | |
83 | buf[3] = bin2bcd(dt->tm_mday); | |
84 | buf[4] = bin2bcd(dt->tm_mon + 1); | |
85 | buf[5] = bin2bcd(dt->tm_wday + 1); | |
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86 | |
87 | /* year in linux is from 1900 i.e in range of 100 | |
88 | in rtc it is from 00 to 99 */ | |
89 | dt->tm_year = dt->tm_year % 100; | |
90 | ||
ee85bb5b RG |
91 | buf[6] = bin2bcd(dt->tm_year); |
92 | buf[7] = bin2bcd(0x00); | |
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93 | |
94 | /* write the rtc settings */ | |
ee85bb5b | 95 | return regmap_bulk_write(map, DS1347_CLOCK_BURST, buf, 8); |
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96 | } |
97 | ||
98 | static const struct rtc_class_ops ds1347_rtc_ops = { | |
99 | .read_time = ds1347_read_time, | |
100 | .set_time = ds1347_set_time, | |
101 | }; | |
102 | ||
103 | static int ds1347_probe(struct spi_device *spi) | |
104 | { | |
105 | struct rtc_device *rtc; | |
ee85bb5b RG |
106 | struct regmap_config config; |
107 | struct regmap *map; | |
108 | unsigned int data; | |
617b26a0 RG |
109 | int res; |
110 | ||
ee85bb5b RG |
111 | memset(&config, 0, sizeof(config)); |
112 | config.reg_bits = 8; | |
113 | config.val_bits = 8; | |
114 | config.read_flag_mask = 0x80; | |
115 | config.max_register = 0x3F; | |
116 | config.wr_table = &ds1347_access_table; | |
117 | ||
617b26a0 RG |
118 | /* spi setup with ds1347 in mode 3 and bits per word as 8 */ |
119 | spi->mode = SPI_MODE_3; | |
120 | spi->bits_per_word = 8; | |
121 | spi_setup(spi); | |
122 | ||
ee85bb5b RG |
123 | map = devm_regmap_init_spi(spi, &config); |
124 | ||
125 | if (IS_ERR(map)) { | |
126 | dev_err(&spi->dev, "ds1347 regmap init spi failed\n"); | |
127 | return PTR_ERR(map); | |
128 | } | |
129 | ||
130 | spi_set_drvdata(spi, map); | |
131 | ||
617b26a0 | 132 | /* RTC Settings */ |
ee85bb5b | 133 | res = regmap_read(map, DS1347_SECONDS_REG, &data); |
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134 | if (res) |
135 | return res; | |
136 | ||
137 | /* Disable the write protect of rtc */ | |
ee85bb5b | 138 | regmap_read(map, DS1347_CONTROL_REG, &data); |
617b26a0 | 139 | data = data & ~(1<<7); |
ee85bb5b | 140 | regmap_write(map, DS1347_CONTROL_REG, data); |
617b26a0 RG |
141 | |
142 | /* Enable the oscillator , disable the oscillator stop flag, | |
143 | and glitch filter to reduce current consumption */ | |
ee85bb5b | 144 | regmap_read(map, DS1347_STATUS_REG, &data); |
617b26a0 | 145 | data = data & 0x1B; |
ee85bb5b | 146 | regmap_write(map, DS1347_STATUS_REG, data); |
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147 | |
148 | /* display the settings */ | |
ee85bb5b | 149 | regmap_read(map, DS1347_CONTROL_REG, &data); |
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150 | dev_info(&spi->dev, "DS1347 RTC CTRL Reg = 0x%02x\n", data); |
151 | ||
ee85bb5b | 152 | regmap_read(map, DS1347_STATUS_REG, &data); |
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153 | dev_info(&spi->dev, "DS1347 RTC Status Reg = 0x%02x\n", data); |
154 | ||
155 | rtc = devm_rtc_device_register(&spi->dev, "ds1347", | |
156 | &ds1347_rtc_ops, THIS_MODULE); | |
157 | ||
158 | if (IS_ERR(rtc)) | |
159 | return PTR_ERR(rtc); | |
160 | ||
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161 | return 0; |
162 | } | |
163 | ||
164 | static struct spi_driver ds1347_driver = { | |
165 | .driver = { | |
166 | .name = "ds1347", | |
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167 | }, |
168 | .probe = ds1347_probe, | |
169 | }; | |
170 | ||
171 | module_spi_driver(ds1347_driver); | |
172 | ||
173 | MODULE_DESCRIPTION("DS1347 SPI RTC DRIVER"); | |
174 | MODULE_AUTHOR("Raghavendra C Ganiga <ravi23ganiga@gmail.com>"); | |
175 | MODULE_LICENSE("GPL v2"); |