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1 | /* drivers/char/max6902.c |
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 | |
16 | * Converted to rtc_device and uses the SPI layer. | |
17 | * | |
18 | * ??-???-2005: Someone at Compulab | |
19 | * - Initial driver creation. | |
20 | */ | |
21 | ||
22 | #include <linux/config.h> | |
23 | #include <linux/module.h> | |
24 | #include <linux/version.h> | |
25 | ||
26 | #include <linux/kernel.h> | |
27 | #include <linux/platform_device.h> | |
28 | #include <linux/init.h> | |
29 | #include <linux/rtc.h> | |
30 | #include <linux/spi/spi.h> | |
31 | #include <linux/bcd.h> | |
32 | #include <linux/delay.h> | |
33 | ||
34 | #define MAX6902_REG_SECONDS 0x01 | |
35 | #define MAX6902_REG_MINUTES 0x03 | |
36 | #define MAX6902_REG_HOURS 0x05 | |
37 | #define MAX6902_REG_DATE 0x07 | |
38 | #define MAX6902_REG_MONTH 0x09 | |
39 | #define MAX6902_REG_DAY 0x0B | |
40 | #define MAX6902_REG_YEAR 0x0D | |
41 | #define MAX6902_REG_CONTROL 0x0F | |
42 | #define MAX6902_REG_CENTURY 0x13 | |
43 | ||
44 | #undef MAX6902_DEBUG | |
45 | ||
46 | struct max6902 { | |
47 | struct rtc_device *rtc; | |
48 | u8 buf[9]; /* Burst read cmd + 8 registers */ | |
49 | u8 tx_buf[2]; | |
50 | u8 rx_buf[2]; | |
51 | }; | |
52 | ||
53 | static void max6902_set_reg(struct device *dev, unsigned char address, | |
54 | unsigned char data) | |
55 | { | |
56 | struct spi_device *spi = to_spi_device(dev); | |
57 | unsigned char buf[2]; | |
58 | ||
59 | /* MSB must be '0' to write */ | |
60 | buf[0] = address & 0x7f; | |
61 | buf[1] = data; | |
62 | ||
63 | spi_write(spi, buf, 2); | |
64 | } | |
65 | ||
66 | static int max6902_get_reg(struct device *dev, unsigned char address, | |
67 | unsigned char *data) | |
68 | { | |
69 | struct spi_device *spi = to_spi_device(dev); | |
70 | struct max6902 *chip = dev_get_drvdata(dev); | |
71 | struct spi_message message; | |
72 | struct spi_transfer xfer; | |
73 | int status; | |
74 | ||
75 | if (!data) | |
76 | return -EINVAL; | |
77 | ||
78 | /* Build our spi message */ | |
79 | spi_message_init(&message); | |
80 | memset(&xfer, 0, sizeof(xfer)); | |
81 | xfer.len = 2; | |
82 | /* Can tx_buf and rx_buf be equal? The doc in spi.h is not sure... */ | |
83 | xfer.tx_buf = chip->tx_buf; | |
84 | xfer.rx_buf = chip->rx_buf; | |
85 | ||
86 | /* Set MSB to indicate read */ | |
87 | chip->tx_buf[0] = address | 0x80; | |
88 | ||
89 | spi_message_add_tail(&xfer, &message); | |
90 | ||
91 | /* do the i/o */ | |
92 | status = spi_sync(spi, &message); | |
93 | if (status == 0) | |
94 | status = message.status; | |
95 | else | |
96 | return status; | |
97 | ||
98 | *data = chip->rx_buf[1]; | |
99 | ||
100 | return status; | |
101 | } | |
102 | ||
103 | static int max6902_get_datetime(struct device *dev, struct rtc_time *dt) | |
104 | { | |
105 | unsigned char tmp; | |
106 | int century; | |
107 | int err; | |
108 | struct spi_device *spi = to_spi_device(dev); | |
109 | struct max6902 *chip = dev_get_drvdata(dev); | |
110 | struct spi_message message; | |
111 | struct spi_transfer xfer; | |
112 | int status; | |
113 | ||
114 | err = max6902_get_reg(dev, MAX6902_REG_CENTURY, &tmp); | |
115 | if (err) | |
116 | return err; | |
117 | ||
118 | /* build the message */ | |
119 | spi_message_init(&message); | |
120 | memset(&xfer, 0, sizeof(xfer)); | |
121 | xfer.len = 1 + 7; /* Burst read command + 7 registers */ | |
122 | xfer.tx_buf = chip->buf; | |
123 | xfer.rx_buf = chip->buf; | |
124 | chip->buf[0] = 0xbf; /* Burst read */ | |
125 | spi_message_add_tail(&xfer, &message); | |
126 | ||
127 | /* do the i/o */ | |
128 | status = spi_sync(spi, &message); | |
129 | if (status == 0) | |
130 | status = message.status; | |
131 | else | |
132 | return status; | |
133 | ||
134 | /* The chip sends data in this order: | |
135 | * Seconds, Minutes, Hours, Date, Month, Day, Year */ | |
136 | dt->tm_sec = BCD2BIN(chip->buf[1]); | |
137 | dt->tm_min = BCD2BIN(chip->buf[2]); | |
138 | dt->tm_hour = BCD2BIN(chip->buf[3]); | |
139 | dt->tm_mday = BCD2BIN(chip->buf[4]); | |
140 | dt->tm_mon = BCD2BIN(chip->buf[5] - 1); | |
141 | dt->tm_wday = BCD2BIN(chip->buf[6]); | |
142 | dt->tm_year = BCD2BIN(chip->buf[7]); | |
143 | ||
144 | century = BCD2BIN(tmp) * 100; | |
145 | ||
146 | dt->tm_year += century; | |
147 | dt->tm_year -= 1900; | |
148 | ||
149 | #ifdef MAX6902_DEBUG | |
150 | printk("\n%s : Read RTC values\n",__FUNCTION__); | |
151 | printk("tm_hour: %i\n",dt->tm_hour); | |
152 | printk("tm_min : %i\n",dt->tm_min); | |
153 | printk("tm_sec : %i\n",dt->tm_sec); | |
154 | printk("tm_year: %i\n",dt->tm_year); | |
155 | printk("tm_mon : %i\n",dt->tm_mon); | |
156 | printk("tm_mday: %i\n",dt->tm_mday); | |
157 | printk("tm_wday: %i\n",dt->tm_wday); | |
158 | #endif | |
159 | ||
160 | return 0; | |
161 | } | |
162 | ||
163 | static int max6902_set_datetime(struct device *dev, struct rtc_time *dt) | |
164 | { | |
165 | dt->tm_year = dt->tm_year+1900; | |
166 | ||
167 | #ifdef MAX6902_DEBUG | |
168 | printk("\n%s : Setting RTC values\n",__FUNCTION__); | |
169 | printk("tm_sec : %i\n",dt->tm_sec); | |
170 | printk("tm_min : %i\n",dt->tm_min); | |
171 | printk("tm_hour: %i\n",dt->tm_hour); | |
172 | printk("tm_mday: %i\n",dt->tm_mday); | |
173 | printk("tm_wday: %i\n",dt->tm_wday); | |
174 | printk("tm_year: %i\n",dt->tm_year); | |
175 | #endif | |
176 | ||
177 | /* Remove write protection */ | |
178 | max6902_set_reg(dev, 0xF, 0); | |
179 | ||
180 | max6902_set_reg(dev, 0x01, BIN2BCD(dt->tm_sec)); | |
181 | max6902_set_reg(dev, 0x03, BIN2BCD(dt->tm_min)); | |
182 | max6902_set_reg(dev, 0x05, BIN2BCD(dt->tm_hour)); | |
183 | ||
184 | max6902_set_reg(dev, 0x07, BIN2BCD(dt->tm_mday)); | |
185 | max6902_set_reg(dev, 0x09, BIN2BCD(dt->tm_mon+1)); | |
186 | max6902_set_reg(dev, 0x0B, BIN2BCD(dt->tm_wday)); | |
187 | max6902_set_reg(dev, 0x0D, BIN2BCD(dt->tm_year%100)); | |
188 | max6902_set_reg(dev, 0x13, BIN2BCD(dt->tm_year/100)); | |
189 | ||
190 | /* Compulab used a delay here. However, the datasheet | |
191 | * does not mention a delay being required anywhere... */ | |
192 | /* delay(2000); */ | |
193 | ||
194 | /* Write protect */ | |
195 | max6902_set_reg(dev, 0xF, 0x80); | |
196 | ||
197 | return 0; | |
198 | } | |
199 | ||
200 | static int max6902_read_time(struct device *dev, struct rtc_time *tm) | |
201 | { | |
202 | return max6902_get_datetime(dev, tm); | |
203 | } | |
204 | ||
205 | static int max6902_set_time(struct device *dev, struct rtc_time *tm) | |
206 | { | |
207 | return max6902_set_datetime(dev, tm); | |
208 | } | |
209 | ||
ff8371ac | 210 | static const struct rtc_class_ops max6902_rtc_ops = { |
8e12ecc2 RA |
211 | .read_time = max6902_read_time, |
212 | .set_time = max6902_set_time, | |
213 | }; | |
214 | ||
215 | static int __devinit max6902_probe(struct spi_device *spi) | |
216 | { | |
217 | struct rtc_device *rtc; | |
218 | unsigned char tmp; | |
219 | struct max6902 *chip; | |
220 | int res; | |
221 | ||
222 | rtc = rtc_device_register("max6902", | |
223 | &spi->dev, &max6902_rtc_ops, THIS_MODULE); | |
224 | if (IS_ERR(rtc)) | |
225 | return PTR_ERR(rtc); | |
226 | ||
227 | spi->mode = SPI_MODE_3; | |
228 | spi->bits_per_word = 8; | |
229 | spi_setup(spi); | |
230 | ||
231 | chip = kzalloc(sizeof *chip, GFP_KERNEL); | |
232 | if (!chip) { | |
233 | rtc_device_unregister(rtc); | |
234 | return -ENOMEM; | |
235 | } | |
236 | chip->rtc = rtc; | |
237 | dev_set_drvdata(&spi->dev, chip); | |
238 | ||
239 | res = max6902_get_reg(&spi->dev, MAX6902_REG_SECONDS, &tmp); | |
240 | if (res) { | |
241 | rtc_device_unregister(rtc); | |
242 | return res; | |
243 | } | |
244 | ||
245 | return 0; | |
246 | } | |
247 | ||
248 | static int __devexit max6902_remove(struct spi_device *spi) | |
249 | { | |
250 | struct max6902 *chip = platform_get_drvdata(spi); | |
251 | struct rtc_device *rtc = chip->rtc; | |
252 | ||
253 | if (rtc) | |
254 | rtc_device_unregister(rtc); | |
255 | ||
256 | kfree(chip); | |
257 | ||
258 | return 0; | |
259 | } | |
260 | ||
261 | static struct spi_driver max6902_driver = { | |
262 | .driver = { | |
263 | .name = "max6902", | |
264 | .bus = &spi_bus_type, | |
265 | .owner = THIS_MODULE, | |
266 | }, | |
267 | .probe = max6902_probe, | |
268 | .remove = __devexit_p(max6902_remove), | |
269 | }; | |
270 | ||
271 | static __init int max6902_init(void) | |
272 | { | |
273 | printk("max6902 spi driver\n"); | |
274 | return spi_register_driver(&max6902_driver); | |
275 | } | |
276 | module_init(max6902_init); | |
277 | ||
278 | static __exit void max6902_exit(void) | |
279 | { | |
280 | spi_unregister_driver(&max6902_driver); | |
281 | } | |
282 | module_exit(max6902_exit); | |
283 | ||
284 | MODULE_DESCRIPTION ("max6902 spi RTC driver"); | |
285 | MODULE_AUTHOR ("Raphael Assenat"); | |
286 | MODULE_LICENSE ("GPL"); |