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06de1808 MJ |
1 | /* |
2 | * rtc-ds1390.c -- driver for DS1390/93/94 | |
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 | * | |
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 | |
13 | * (alarms, trickle charger, different control registers) are unavailable. | |
14 | */ | |
15 | ||
16 | #include <linux/platform_device.h> | |
17 | #include <linux/rtc.h> | |
18 | #include <linux/spi/spi.h> | |
19 | #include <linux/bcd.h> | |
20 | ||
21 | #define DS1390_REG_100THS 0x00 | |
22 | #define DS1390_REG_SECONDS 0x01 | |
23 | #define DS1390_REG_MINUTES 0x02 | |
24 | #define DS1390_REG_HOURS 0x03 | |
25 | #define DS1390_REG_DAY 0x04 | |
26 | #define DS1390_REG_DATE 0x05 | |
27 | #define DS1390_REG_MONTH_CENT 0x06 | |
28 | #define DS1390_REG_YEAR 0x07 | |
29 | ||
30 | #define DS1390_REG_ALARM_100THS 0x08 | |
31 | #define DS1390_REG_ALARM_SECONDS 0x09 | |
32 | #define DS1390_REG_ALARM_MINUTES 0x0A | |
33 | #define DS1390_REG_ALARM_HOURS 0x0B | |
34 | #define DS1390_REG_ALARM_DAY_DATE 0x0C | |
35 | ||
36 | #define DS1390_REG_CONTROL 0x0D | |
37 | #define DS1390_REG_STATUS 0x0E | |
38 | #define DS1390_REG_TRICKLE 0x0F | |
39 | ||
40 | struct ds1390 { | |
41 | struct rtc_device *rtc; | |
42 | u8 txrx_buf[9]; /* cmd + 8 registers */ | |
43 | }; | |
44 | ||
45 | static void ds1390_set_reg(struct device *dev, unsigned char address, | |
46 | unsigned char data) | |
47 | { | |
48 | struct spi_device *spi = to_spi_device(dev); | |
49 | struct ds1390 *chip = dev_get_drvdata(dev); | |
50 | ||
51 | /* Set MSB to indicate write */ | |
52 | chip->txrx_buf[0] = address | 0x80; | |
53 | chip->txrx_buf[1] = data; | |
54 | ||
55 | /* do the i/o */ | |
56 | spi_write_then_read(spi, chip->txrx_buf, 2, NULL, 0); | |
57 | } | |
58 | ||
59 | static int ds1390_get_reg(struct device *dev, unsigned char address, | |
60 | unsigned char *data) | |
61 | { | |
62 | struct spi_device *spi = to_spi_device(dev); | |
63 | struct ds1390 *chip = dev_get_drvdata(dev); | |
64 | int status; | |
65 | ||
66 | if (!data) | |
67 | return -EINVAL; | |
68 | ||
69 | /* Clear MSB to indicate read */ | |
70 | chip->txrx_buf[0] = address & 0x7f; | |
71 | /* do the i/o */ | |
72 | status = spi_write_then_read(spi, chip->txrx_buf, 1, chip->txrx_buf, 1); | |
73 | if (status != 0) | |
74 | return status; | |
75 | ||
76 | *data = chip->txrx_buf[1]; | |
77 | ||
78 | return 0; | |
79 | } | |
80 | ||
81 | static int ds1390_get_datetime(struct device *dev, struct rtc_time *dt) | |
82 | { | |
83 | struct spi_device *spi = to_spi_device(dev); | |
84 | struct ds1390 *chip = dev_get_drvdata(dev); | |
85 | int status; | |
86 | ||
87 | /* build the message */ | |
88 | chip->txrx_buf[0] = DS1390_REG_SECONDS; | |
89 | ||
90 | /* do the i/o */ | |
91 | status = spi_write_then_read(spi, chip->txrx_buf, 1, chip->txrx_buf, 8); | |
92 | if (status != 0) | |
93 | return status; | |
94 | ||
95 | /* The chip sends data in this order: | |
96 | * Seconds, Minutes, Hours, Day, Date, Month / Century, Year */ | |
97 | dt->tm_sec = bcd2bin(chip->txrx_buf[0]); | |
98 | dt->tm_min = bcd2bin(chip->txrx_buf[1]); | |
99 | dt->tm_hour = bcd2bin(chip->txrx_buf[2]); | |
100 | dt->tm_wday = bcd2bin(chip->txrx_buf[3]); | |
101 | dt->tm_mday = bcd2bin(chip->txrx_buf[4]); | |
102 | /* mask off century bit */ | |
103 | dt->tm_mon = bcd2bin(chip->txrx_buf[5] & 0x7f) - 1; | |
104 | /* adjust for century bit */ | |
105 | dt->tm_year = bcd2bin(chip->txrx_buf[6]) + ((chip->txrx_buf[5] & 0x80) ? 100 : 0); | |
106 | ||
107 | return rtc_valid_tm(dt); | |
108 | } | |
109 | ||
110 | static int ds1390_set_datetime(struct device *dev, struct rtc_time *dt) | |
111 | { | |
112 | struct spi_device *spi = to_spi_device(dev); | |
113 | struct ds1390 *chip = dev_get_drvdata(dev); | |
114 | ||
115 | /* build the message */ | |
116 | chip->txrx_buf[0] = DS1390_REG_SECONDS | 0x80; | |
117 | chip->txrx_buf[1] = bin2bcd(dt->tm_sec); | |
118 | chip->txrx_buf[2] = bin2bcd(dt->tm_min); | |
119 | chip->txrx_buf[3] = bin2bcd(dt->tm_hour); | |
120 | chip->txrx_buf[4] = bin2bcd(dt->tm_wday); | |
121 | chip->txrx_buf[5] = bin2bcd(dt->tm_mday); | |
122 | chip->txrx_buf[6] = bin2bcd(dt->tm_mon + 1) | | |
123 | ((dt->tm_year > 99) ? 0x80 : 0x00); | |
124 | chip->txrx_buf[7] = bin2bcd(dt->tm_year % 100); | |
125 | ||
126 | /* do the i/o */ | |
127 | return spi_write_then_read(spi, chip->txrx_buf, 8, NULL, 0); | |
128 | } | |
129 | ||
130 | static int ds1390_read_time(struct device *dev, struct rtc_time *tm) | |
131 | { | |
132 | return ds1390_get_datetime(dev, tm); | |
133 | } | |
134 | ||
135 | static int ds1390_set_time(struct device *dev, struct rtc_time *tm) | |
136 | { | |
137 | return ds1390_set_datetime(dev, tm); | |
138 | } | |
139 | ||
140 | static const struct rtc_class_ops ds1390_rtc_ops = { | |
141 | .read_time = ds1390_read_time, | |
142 | .set_time = ds1390_set_time, | |
143 | }; | |
144 | ||
145 | static int __devinit ds1390_probe(struct spi_device *spi) | |
146 | { | |
147 | struct rtc_device *rtc; | |
148 | unsigned char tmp; | |
149 | struct ds1390 *chip; | |
150 | int res; | |
151 | ||
152 | printk(KERN_DEBUG "DS1390 SPI RTC driver\n"); | |
153 | ||
154 | rtc = rtc_device_register("ds1390", | |
155 | &spi->dev, &ds1390_rtc_ops, THIS_MODULE); | |
156 | if (IS_ERR(rtc)) { | |
157 | printk(KERN_ALERT "RTC : unable to register device\n"); | |
158 | return PTR_ERR(rtc); | |
159 | } | |
160 | ||
161 | spi->mode = SPI_MODE_3; | |
162 | spi->bits_per_word = 8; | |
163 | spi_setup(spi); | |
164 | ||
165 | chip = kzalloc(sizeof *chip, GFP_KERNEL); | |
166 | if (!chip) { | |
167 | printk(KERN_ALERT "RTC : unable to allocate device memory\n"); | |
168 | rtc_device_unregister(rtc); | |
169 | return -ENOMEM; | |
170 | } | |
171 | chip->rtc = rtc; | |
172 | dev_set_drvdata(&spi->dev, chip); | |
173 | ||
174 | res = ds1390_get_reg(&spi->dev, DS1390_REG_SECONDS, &tmp); | |
175 | if (res) { | |
176 | printk(KERN_ALERT "RTC : unable to read device\n"); | |
177 | rtc_device_unregister(rtc); | |
178 | return res; | |
179 | } | |
180 | ||
181 | return 0; | |
182 | } | |
183 | ||
184 | static int __devexit ds1390_remove(struct spi_device *spi) | |
185 | { | |
186 | struct ds1390 *chip = platform_get_drvdata(spi); | |
187 | struct rtc_device *rtc = chip->rtc; | |
188 | ||
189 | if (rtc) | |
190 | rtc_device_unregister(rtc); | |
191 | ||
192 | kfree(chip); | |
193 | ||
194 | return 0; | |
195 | } | |
196 | ||
197 | static struct spi_driver ds1390_driver = { | |
198 | .driver = { | |
199 | .name = "rtc-ds1390", | |
200 | .owner = THIS_MODULE, | |
201 | }, | |
202 | .probe = ds1390_probe, | |
203 | .remove = __devexit_p(ds1390_remove), | |
204 | }; | |
205 | ||
206 | static __init int ds1390_init(void) | |
207 | { | |
208 | return spi_register_driver(&ds1390_driver); | |
209 | } | |
210 | module_init(ds1390_init); | |
211 | ||
212 | static __exit void ds1390_exit(void) | |
213 | { | |
214 | spi_unregister_driver(&ds1390_driver); | |
215 | } | |
216 | module_exit(ds1390_exit); | |
217 | ||
218 | MODULE_DESCRIPTION("DS1390/93/94 SPI RTC driver"); | |
219 | MODULE_AUTHOR("Mark Jackson <mpfj@mimc.co.uk>"); | |
220 | MODULE_LICENSE("GPL"); |