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f30c2269 | 1 | /* drivers/rtc/rtc-max6902.c |
8e12ecc2 RA |
2 | * |
3 | * Copyright (C) 2006 8D Technologies inc. | |
4 | * Copyright (C) 2004 Compulab Ltd. | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License version 2 as | |
8 | * published by the Free Software Foundation. | |
9 | * | |
10 | * Driver for MAX6902 spi RTC | |
11 | * | |
12 | * Changelog: | |
13 | * | |
14 | * 24-May-2006: Raphael Assenat <raph@8d.com> | |
15 | * - Major rework | |
5c076fce | 16 | * Converted to rtc_device and uses the SPI layer. |
8e12ecc2 RA |
17 | * |
18 | * ??-???-2005: Someone at Compulab | |
19 | * - Initial driver creation. | |
20 | */ | |
21 | ||
8e12ecc2 RA |
22 | #include <linux/module.h> |
23 | #include <linux/version.h> | |
24 | ||
25 | #include <linux/kernel.h> | |
26 | #include <linux/platform_device.h> | |
27 | #include <linux/init.h> | |
28 | #include <linux/rtc.h> | |
29 | #include <linux/spi/spi.h> | |
30 | #include <linux/bcd.h> | |
31 | #include <linux/delay.h> | |
32 | ||
33 | #define MAX6902_REG_SECONDS 0x01 | |
34 | #define MAX6902_REG_MINUTES 0x03 | |
35 | #define MAX6902_REG_HOURS 0x05 | |
36 | #define MAX6902_REG_DATE 0x07 | |
37 | #define MAX6902_REG_MONTH 0x09 | |
38 | #define MAX6902_REG_DAY 0x0B | |
39 | #define MAX6902_REG_YEAR 0x0D | |
40 | #define MAX6902_REG_CONTROL 0x0F | |
41 | #define MAX6902_REG_CENTURY 0x13 | |
42 | ||
43 | #undef MAX6902_DEBUG | |
44 | ||
45 | struct max6902 { | |
46 | struct rtc_device *rtc; | |
47 | u8 buf[9]; /* Burst read cmd + 8 registers */ | |
48 | u8 tx_buf[2]; | |
49 | u8 rx_buf[2]; | |
50 | }; | |
51 | ||
52 | static void max6902_set_reg(struct device *dev, unsigned char address, | |
53 | unsigned char data) | |
54 | { | |
55 | struct spi_device *spi = to_spi_device(dev); | |
56 | unsigned char buf[2]; | |
57 | ||
58 | /* MSB must be '0' to write */ | |
59 | buf[0] = address & 0x7f; | |
60 | buf[1] = data; | |
61 | ||
62 | spi_write(spi, buf, 2); | |
63 | } | |
64 | ||
65 | static int max6902_get_reg(struct device *dev, unsigned char address, | |
66 | unsigned char *data) | |
67 | { | |
68 | struct spi_device *spi = to_spi_device(dev); | |
69 | struct max6902 *chip = dev_get_drvdata(dev); | |
70 | struct spi_message message; | |
71 | struct spi_transfer xfer; | |
72 | int status; | |
73 | ||
74 | if (!data) | |
75 | return -EINVAL; | |
76 | ||
77 | /* Build our spi message */ | |
78 | spi_message_init(&message); | |
79 | memset(&xfer, 0, sizeof(xfer)); | |
80 | xfer.len = 2; | |
81 | /* Can tx_buf and rx_buf be equal? The doc in spi.h is not sure... */ | |
82 | xfer.tx_buf = chip->tx_buf; | |
83 | xfer.rx_buf = chip->rx_buf; | |
84 | ||
85 | /* Set MSB to indicate read */ | |
86 | chip->tx_buf[0] = address | 0x80; | |
87 | ||
88 | spi_message_add_tail(&xfer, &message); | |
89 | ||
90 | /* do the i/o */ | |
91 | status = spi_sync(spi, &message); | |
8e12ecc2 | 92 | |
c24b2602 MP |
93 | if (status == 0) |
94 | *data = chip->rx_buf[1]; | |
8e12ecc2 RA |
95 | return status; |
96 | } | |
97 | ||
98 | static int max6902_get_datetime(struct device *dev, struct rtc_time *dt) | |
99 | { | |
100 | unsigned char tmp; | |
101 | int century; | |
102 | int err; | |
103 | struct spi_device *spi = to_spi_device(dev); | |
104 | struct max6902 *chip = dev_get_drvdata(dev); | |
105 | struct spi_message message; | |
106 | struct spi_transfer xfer; | |
107 | int status; | |
108 | ||
109 | err = max6902_get_reg(dev, MAX6902_REG_CENTURY, &tmp); | |
110 | if (err) | |
111 | return err; | |
112 | ||
113 | /* build the message */ | |
114 | spi_message_init(&message); | |
115 | memset(&xfer, 0, sizeof(xfer)); | |
116 | xfer.len = 1 + 7; /* Burst read command + 7 registers */ | |
117 | xfer.tx_buf = chip->buf; | |
118 | xfer.rx_buf = chip->buf; | |
119 | chip->buf[0] = 0xbf; /* Burst read */ | |
120 | spi_message_add_tail(&xfer, &message); | |
121 | ||
122 | /* do the i/o */ | |
123 | status = spi_sync(spi, &message); | |
c24b2602 | 124 | if (status) |
8e12ecc2 RA |
125 | return status; |
126 | ||
127 | /* The chip sends data in this order: | |
128 | * Seconds, Minutes, Hours, Date, Month, Day, Year */ | |
129 | dt->tm_sec = BCD2BIN(chip->buf[1]); | |
130 | dt->tm_min = BCD2BIN(chip->buf[2]); | |
131 | dt->tm_hour = BCD2BIN(chip->buf[3]); | |
132 | dt->tm_mday = BCD2BIN(chip->buf[4]); | |
c430169e | 133 | dt->tm_mon = BCD2BIN(chip->buf[5]) - 1; |
8e12ecc2 RA |
134 | dt->tm_wday = BCD2BIN(chip->buf[6]); |
135 | dt->tm_year = BCD2BIN(chip->buf[7]); | |
136 | ||
137 | century = BCD2BIN(tmp) * 100; | |
138 | ||
139 | dt->tm_year += century; | |
140 | dt->tm_year -= 1900; | |
141 | ||
142 | #ifdef MAX6902_DEBUG | |
143 | printk("\n%s : Read RTC values\n",__FUNCTION__); | |
144 | printk("tm_hour: %i\n",dt->tm_hour); | |
145 | printk("tm_min : %i\n",dt->tm_min); | |
146 | printk("tm_sec : %i\n",dt->tm_sec); | |
147 | printk("tm_year: %i\n",dt->tm_year); | |
148 | printk("tm_mon : %i\n",dt->tm_mon); | |
149 | printk("tm_mday: %i\n",dt->tm_mday); | |
150 | printk("tm_wday: %i\n",dt->tm_wday); | |
151 | #endif | |
152 | ||
153 | return 0; | |
154 | } | |
155 | ||
156 | static int max6902_set_datetime(struct device *dev, struct rtc_time *dt) | |
157 | { | |
158 | dt->tm_year = dt->tm_year+1900; | |
159 | ||
160 | #ifdef MAX6902_DEBUG | |
161 | printk("\n%s : Setting RTC values\n",__FUNCTION__); | |
162 | printk("tm_sec : %i\n",dt->tm_sec); | |
163 | printk("tm_min : %i\n",dt->tm_min); | |
164 | printk("tm_hour: %i\n",dt->tm_hour); | |
165 | printk("tm_mday: %i\n",dt->tm_mday); | |
166 | printk("tm_wday: %i\n",dt->tm_wday); | |
167 | printk("tm_year: %i\n",dt->tm_year); | |
168 | #endif | |
169 | ||
170 | /* Remove write protection */ | |
171 | max6902_set_reg(dev, 0xF, 0); | |
172 | ||
173 | max6902_set_reg(dev, 0x01, BIN2BCD(dt->tm_sec)); | |
174 | max6902_set_reg(dev, 0x03, BIN2BCD(dt->tm_min)); | |
175 | max6902_set_reg(dev, 0x05, BIN2BCD(dt->tm_hour)); | |
176 | ||
177 | max6902_set_reg(dev, 0x07, BIN2BCD(dt->tm_mday)); | |
178 | max6902_set_reg(dev, 0x09, BIN2BCD(dt->tm_mon+1)); | |
179 | max6902_set_reg(dev, 0x0B, BIN2BCD(dt->tm_wday)); | |
180 | max6902_set_reg(dev, 0x0D, BIN2BCD(dt->tm_year%100)); | |
181 | max6902_set_reg(dev, 0x13, BIN2BCD(dt->tm_year/100)); | |
182 | ||
183 | /* Compulab used a delay here. However, the datasheet | |
184 | * does not mention a delay being required anywhere... */ | |
185 | /* delay(2000); */ | |
186 | ||
187 | /* Write protect */ | |
188 | max6902_set_reg(dev, 0xF, 0x80); | |
189 | ||
190 | return 0; | |
191 | } | |
192 | ||
193 | static int max6902_read_time(struct device *dev, struct rtc_time *tm) | |
194 | { | |
195 | return max6902_get_datetime(dev, tm); | |
196 | } | |
197 | ||
198 | static int max6902_set_time(struct device *dev, struct rtc_time *tm) | |
199 | { | |
200 | return max6902_set_datetime(dev, tm); | |
201 | } | |
202 | ||
ff8371ac | 203 | static const struct rtc_class_ops max6902_rtc_ops = { |
8e12ecc2 RA |
204 | .read_time = max6902_read_time, |
205 | .set_time = max6902_set_time, | |
206 | }; | |
207 | ||
208 | static int __devinit max6902_probe(struct spi_device *spi) | |
209 | { | |
210 | struct rtc_device *rtc; | |
211 | unsigned char tmp; | |
212 | struct max6902 *chip; | |
213 | int res; | |
214 | ||
215 | rtc = rtc_device_register("max6902", | |
216 | &spi->dev, &max6902_rtc_ops, THIS_MODULE); | |
217 | if (IS_ERR(rtc)) | |
218 | return PTR_ERR(rtc); | |
219 | ||
220 | spi->mode = SPI_MODE_3; | |
221 | spi->bits_per_word = 8; | |
222 | spi_setup(spi); | |
223 | ||
224 | chip = kzalloc(sizeof *chip, GFP_KERNEL); | |
225 | if (!chip) { | |
226 | rtc_device_unregister(rtc); | |
227 | return -ENOMEM; | |
228 | } | |
229 | chip->rtc = rtc; | |
230 | dev_set_drvdata(&spi->dev, chip); | |
231 | ||
232 | res = max6902_get_reg(&spi->dev, MAX6902_REG_SECONDS, &tmp); | |
233 | if (res) { | |
234 | rtc_device_unregister(rtc); | |
235 | return res; | |
236 | } | |
237 | ||
238 | return 0; | |
239 | } | |
240 | ||
241 | static int __devexit max6902_remove(struct spi_device *spi) | |
242 | { | |
243 | struct max6902 *chip = platform_get_drvdata(spi); | |
244 | struct rtc_device *rtc = chip->rtc; | |
245 | ||
246 | if (rtc) | |
247 | rtc_device_unregister(rtc); | |
248 | ||
249 | kfree(chip); | |
250 | ||
251 | return 0; | |
252 | } | |
253 | ||
254 | static struct spi_driver max6902_driver = { | |
255 | .driver = { | |
5c076fce | 256 | .name = "rtc-max6902", |
8e12ecc2 RA |
257 | .bus = &spi_bus_type, |
258 | .owner = THIS_MODULE, | |
259 | }, | |
5c076fce | 260 | .probe = max6902_probe, |
8e12ecc2 RA |
261 | .remove = __devexit_p(max6902_remove), |
262 | }; | |
263 | ||
264 | static __init int max6902_init(void) | |
265 | { | |
266 | printk("max6902 spi driver\n"); | |
267 | return spi_register_driver(&max6902_driver); | |
268 | } | |
269 | module_init(max6902_init); | |
270 | ||
271 | static __exit void max6902_exit(void) | |
272 | { | |
273 | spi_unregister_driver(&max6902_driver); | |
274 | } | |
275 | module_exit(max6902_exit); | |
276 | ||
277 | MODULE_DESCRIPTION ("max6902 spi RTC driver"); | |
278 | MODULE_AUTHOR ("Raphael Assenat"); | |
279 | MODULE_LICENSE ("GPL"); |