Commit | Line | Data |
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06de1808 | 1 | /* |
7b9b2ef1 | 2 | * rtc-ds1390.c -- driver for the Dallas/Maxim DS1390/93/94 SPI RTC |
06de1808 MJ |
3 | * |
4 | * Copyright (C) 2008 Mercury IMC Ltd | |
5 | * Written by Mark Jackson <mpfj@mimc.co.uk> | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License version 2 as | |
9 | * published by the Free Software Foundation. | |
10 | * | |
7b9b2ef1 AZ |
11 | * NOTE: Currently this driver only supports the bare minimum for read |
12 | * and write the RTC. The extra features provided by the chip family | |
06de1808 MJ |
13 | * (alarms, trickle charger, different control registers) are unavailable. |
14 | */ | |
15 | ||
7b9b2ef1 AZ |
16 | #include <linux/init.h> |
17 | #include <linux/module.h> | |
06de1808 MJ |
18 | #include <linux/platform_device.h> |
19 | #include <linux/rtc.h> | |
20 | #include <linux/spi/spi.h> | |
21 | #include <linux/bcd.h> | |
22 | ||
23 | #define DS1390_REG_100THS 0x00 | |
24 | #define DS1390_REG_SECONDS 0x01 | |
25 | #define DS1390_REG_MINUTES 0x02 | |
26 | #define DS1390_REG_HOURS 0x03 | |
27 | #define DS1390_REG_DAY 0x04 | |
28 | #define DS1390_REG_DATE 0x05 | |
29 | #define DS1390_REG_MONTH_CENT 0x06 | |
30 | #define DS1390_REG_YEAR 0x07 | |
31 | ||
32 | #define DS1390_REG_ALARM_100THS 0x08 | |
33 | #define DS1390_REG_ALARM_SECONDS 0x09 | |
34 | #define DS1390_REG_ALARM_MINUTES 0x0A | |
35 | #define DS1390_REG_ALARM_HOURS 0x0B | |
36 | #define DS1390_REG_ALARM_DAY_DATE 0x0C | |
37 | ||
38 | #define DS1390_REG_CONTROL 0x0D | |
39 | #define DS1390_REG_STATUS 0x0E | |
40 | #define DS1390_REG_TRICKLE 0x0F | |
41 | ||
42 | struct ds1390 { | |
43 | struct rtc_device *rtc; | |
44 | u8 txrx_buf[9]; /* cmd + 8 registers */ | |
45 | }; | |
46 | ||
06de1808 MJ |
47 | static int ds1390_get_reg(struct device *dev, unsigned char address, |
48 | unsigned char *data) | |
49 | { | |
50 | struct spi_device *spi = to_spi_device(dev); | |
51 | struct ds1390 *chip = dev_get_drvdata(dev); | |
52 | int status; | |
53 | ||
54 | if (!data) | |
55 | return -EINVAL; | |
56 | ||
57 | /* Clear MSB to indicate read */ | |
58 | chip->txrx_buf[0] = address & 0x7f; | |
59 | /* do the i/o */ | |
60 | status = spi_write_then_read(spi, chip->txrx_buf, 1, chip->txrx_buf, 1); | |
61 | if (status != 0) | |
62 | return status; | |
63 | ||
64 | *data = chip->txrx_buf[1]; | |
65 | ||
66 | return 0; | |
67 | } | |
68 | ||
7b9b2ef1 | 69 | static int ds1390_read_time(struct device *dev, struct rtc_time *dt) |
06de1808 MJ |
70 | { |
71 | struct spi_device *spi = to_spi_device(dev); | |
72 | struct ds1390 *chip = dev_get_drvdata(dev); | |
73 | int status; | |
74 | ||
75 | /* build the message */ | |
76 | chip->txrx_buf[0] = DS1390_REG_SECONDS; | |
77 | ||
78 | /* do the i/o */ | |
79 | status = spi_write_then_read(spi, chip->txrx_buf, 1, chip->txrx_buf, 8); | |
80 | if (status != 0) | |
81 | return status; | |
82 | ||
83 | /* The chip sends data in this order: | |
84 | * Seconds, Minutes, Hours, Day, Date, Month / Century, Year */ | |
85 | dt->tm_sec = bcd2bin(chip->txrx_buf[0]); | |
86 | dt->tm_min = bcd2bin(chip->txrx_buf[1]); | |
87 | dt->tm_hour = bcd2bin(chip->txrx_buf[2]); | |
88 | dt->tm_wday = bcd2bin(chip->txrx_buf[3]); | |
89 | dt->tm_mday = bcd2bin(chip->txrx_buf[4]); | |
90 | /* mask off century bit */ | |
91 | dt->tm_mon = bcd2bin(chip->txrx_buf[5] & 0x7f) - 1; | |
92 | /* adjust for century bit */ | |
93 | dt->tm_year = bcd2bin(chip->txrx_buf[6]) + ((chip->txrx_buf[5] & 0x80) ? 100 : 0); | |
94 | ||
95 | return rtc_valid_tm(dt); | |
96 | } | |
97 | ||
7b9b2ef1 | 98 | static int ds1390_set_time(struct device *dev, struct rtc_time *dt) |
06de1808 MJ |
99 | { |
100 | struct spi_device *spi = to_spi_device(dev); | |
101 | struct ds1390 *chip = dev_get_drvdata(dev); | |
102 | ||
103 | /* build the message */ | |
104 | chip->txrx_buf[0] = DS1390_REG_SECONDS | 0x80; | |
105 | chip->txrx_buf[1] = bin2bcd(dt->tm_sec); | |
106 | chip->txrx_buf[2] = bin2bcd(dt->tm_min); | |
107 | chip->txrx_buf[3] = bin2bcd(dt->tm_hour); | |
108 | chip->txrx_buf[4] = bin2bcd(dt->tm_wday); | |
109 | chip->txrx_buf[5] = bin2bcd(dt->tm_mday); | |
110 | chip->txrx_buf[6] = bin2bcd(dt->tm_mon + 1) | | |
111 | ((dt->tm_year > 99) ? 0x80 : 0x00); | |
112 | chip->txrx_buf[7] = bin2bcd(dt->tm_year % 100); | |
113 | ||
114 | /* do the i/o */ | |
115 | return spi_write_then_read(spi, chip->txrx_buf, 8, NULL, 0); | |
116 | } | |
117 | ||
06de1808 MJ |
118 | static const struct rtc_class_ops ds1390_rtc_ops = { |
119 | .read_time = ds1390_read_time, | |
120 | .set_time = ds1390_set_time, | |
121 | }; | |
122 | ||
123 | static int __devinit ds1390_probe(struct spi_device *spi) | |
124 | { | |
06de1808 MJ |
125 | unsigned char tmp; |
126 | struct ds1390 *chip; | |
127 | int res; | |
128 | ||
06de1808 MJ |
129 | spi->mode = SPI_MODE_3; |
130 | spi->bits_per_word = 8; | |
131 | spi_setup(spi); | |
132 | ||
133 | chip = kzalloc(sizeof *chip, GFP_KERNEL); | |
134 | if (!chip) { | |
7b9b2ef1 | 135 | dev_err(&spi->dev, "unable to allocate device memory\n"); |
06de1808 MJ |
136 | return -ENOMEM; |
137 | } | |
06de1808 MJ |
138 | dev_set_drvdata(&spi->dev, chip); |
139 | ||
140 | res = ds1390_get_reg(&spi->dev, DS1390_REG_SECONDS, &tmp); | |
7b9b2ef1 AZ |
141 | if (res != 0) { |
142 | dev_err(&spi->dev, "unable to read device\n"); | |
143 | kfree(chip); | |
06de1808 MJ |
144 | return res; |
145 | } | |
146 | ||
7b9b2ef1 AZ |
147 | chip->rtc = rtc_device_register("ds1390", |
148 | &spi->dev, &ds1390_rtc_ops, THIS_MODULE); | |
149 | if (IS_ERR(chip->rtc)) { | |
150 | dev_err(&spi->dev, "unable to register device\n"); | |
151 | res = PTR_ERR(chip->rtc); | |
152 | kfree(chip); | |
153 | } | |
154 | ||
155 | return res; | |
06de1808 MJ |
156 | } |
157 | ||
158 | static int __devexit ds1390_remove(struct spi_device *spi) | |
159 | { | |
160 | struct ds1390 *chip = platform_get_drvdata(spi); | |
06de1808 | 161 | |
7b9b2ef1 | 162 | rtc_device_unregister(chip->rtc); |
06de1808 MJ |
163 | kfree(chip); |
164 | ||
165 | return 0; | |
166 | } | |
167 | ||
168 | static struct spi_driver ds1390_driver = { | |
169 | .driver = { | |
170 | .name = "rtc-ds1390", | |
171 | .owner = THIS_MODULE, | |
172 | }, | |
173 | .probe = ds1390_probe, | |
174 | .remove = __devexit_p(ds1390_remove), | |
175 | }; | |
176 | ||
177 | static __init int ds1390_init(void) | |
178 | { | |
179 | return spi_register_driver(&ds1390_driver); | |
180 | } | |
181 | module_init(ds1390_init); | |
182 | ||
183 | static __exit void ds1390_exit(void) | |
184 | { | |
185 | spi_unregister_driver(&ds1390_driver); | |
186 | } | |
187 | module_exit(ds1390_exit); | |
188 | ||
7b9b2ef1 | 189 | MODULE_DESCRIPTION("Dallas/Maxim DS1390/93/94 SPI RTC driver"); |
06de1808 MJ |
190 | MODULE_AUTHOR("Mark Jackson <mpfj@mimc.co.uk>"); |
191 | MODULE_LICENSE("GPL"); | |
e0626e38 | 192 | MODULE_ALIAS("spi:rtc-ds1390"); |