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1 | /* |
2 | * A SPI driver for the Ricoh RS5C348 RTC |
3 | * |
4 | * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp> |
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 | * The board specific init code should provide characteristics of this |
11 | * device: |
12 | * Mode 1 (High-Active, Shift-Then-Sample), High Avtive CS |
13 | */ |
14 | |
15 | #include <linux/bcd.h> |
16 | #include <linux/delay.h> |
17 | #include <linux/device.h> |
18 | #include <linux/errno.h> |
19 | #include <linux/init.h> |
20 | #include <linux/kernel.h> |
21 | #include <linux/string.h> |
22 | #include <linux/slab.h> |
23 | #include <linux/rtc.h> |
24 | #include <linux/workqueue.h> |
25 | #include <linux/spi/spi.h> |
26 | #include <linux/module.h> |
27 | |
28 | #define DRV_VERSION "0.2" |
29 | |
30 | #define RS5C348_REG_SECS 0 |
31 | #define RS5C348_REG_MINS 1 |
32 | #define RS5C348_REG_HOURS 2 |
33 | #define RS5C348_REG_WDAY 3 |
34 | #define RS5C348_REG_DAY 4 |
35 | #define RS5C348_REG_MONTH 5 |
36 | #define RS5C348_REG_YEAR 6 |
37 | #define RS5C348_REG_CTL1 14 |
38 | #define RS5C348_REG_CTL2 15 |
39 | |
40 | #define RS5C348_SECS_MASK 0x7f |
41 | #define RS5C348_MINS_MASK 0x7f |
42 | #define RS5C348_HOURS_MASK 0x3f |
43 | #define RS5C348_WDAY_MASK 0x03 |
44 | #define RS5C348_DAY_MASK 0x3f |
45 | #define RS5C348_MONTH_MASK 0x1f |
46 | |
47 | #define RS5C348_BIT_PM 0x20 /* REG_HOURS */ |
48 | #define RS5C348_BIT_Y2K 0x80 /* REG_MONTH */ |
49 | #define RS5C348_BIT_24H 0x20 /* REG_CTL1 */ |
50 | #define RS5C348_BIT_XSTP 0x10 /* REG_CTL2 */ |
51 | #define RS5C348_BIT_VDET 0x40 /* REG_CTL2 */ |
52 | |
53 | #define RS5C348_CMD_W(addr) (((addr) << 4) | 0x08) /* single write */ |
54 | #define RS5C348_CMD_R(addr) (((addr) << 4) | 0x0c) /* single read */ |
55 | #define RS5C348_CMD_MW(addr) (((addr) << 4) | 0x00) /* burst write */ |
56 | #define RS5C348_CMD_MR(addr) (((addr) << 4) | 0x04) /* burst read */ |
57 | |
58 | struct rs5c348_plat_data { |
59 | struct rtc_device *rtc; |
60 | int rtc_24h; |
61 | }; |
62 | |
63 | static int |
64 | rs5c348_rtc_set_time(struct device *dev, struct rtc_time *tm) |
65 | { |
66 | struct spi_device *spi = to_spi_device(dev); |
67 | struct rs5c348_plat_data *pdata = spi->dev.platform_data; |
68 | u8 txbuf[5+7], *txp; |
69 | int ret; |
70 | |
71 | /* Transfer 5 bytes before writing SEC. This gives 31us for carry. */ |
72 | txp = txbuf; |
73 | txbuf[0] = RS5C348_CMD_R(RS5C348_REG_CTL2); /* cmd, ctl2 */ |
74 | txbuf[1] = 0; /* dummy */ |
75 | txbuf[2] = RS5C348_CMD_R(RS5C348_REG_CTL2); /* cmd, ctl2 */ |
76 | txbuf[3] = 0; /* dummy */ |
77 | txbuf[4] = RS5C348_CMD_MW(RS5C348_REG_SECS); /* cmd, sec, ... */ |
78 | txp = &txbuf[5]; |
79 | txp[RS5C348_REG_SECS] = bin2bcd(tm->tm_sec); |
80 | txp[RS5C348_REG_MINS] = bin2bcd(tm->tm_min); |
81 | if (pdata->rtc_24h) { |
82 | txp[RS5C348_REG_HOURS] = bin2bcd(tm->tm_hour); |
83 | } else { |
84 | /* hour 0 is AM12, noon is PM12 */ |
85 | txp[RS5C348_REG_HOURS] = bin2bcd((tm->tm_hour + 11) % 12 + 1) | |
86 | (tm->tm_hour >= 12 ? RS5C348_BIT_PM : 0); |
87 | } |
88 | txp[RS5C348_REG_WDAY] = bin2bcd(tm->tm_wday); |
89 | txp[RS5C348_REG_DAY] = bin2bcd(tm->tm_mday); |
90 | txp[RS5C348_REG_MONTH] = bin2bcd(tm->tm_mon + 1) | |
91 | (tm->tm_year >= 100 ? RS5C348_BIT_Y2K : 0); |
92 | txp[RS5C348_REG_YEAR] = bin2bcd(tm->tm_year % 100); |
93 | /* write in one transfer to avoid data inconsistency */ |
94 | ret = spi_write_then_read(spi, txbuf, sizeof(txbuf), NULL, 0); |
95 | udelay(62); /* Tcsr 62us */ |
96 | return ret; |
97 | } |
98 | |
99 | static int |
100 | rs5c348_rtc_read_time(struct device *dev, struct rtc_time *tm) |
101 | { |
102 | struct spi_device *spi = to_spi_device(dev); |
103 | struct rs5c348_plat_data *pdata = spi->dev.platform_data; |
104 | u8 txbuf[5], rxbuf[7]; |
105 | int ret; |
106 | |
107 | /* Transfer 5 byte befores reading SEC. This gives 31us for carry. */ |
108 | txbuf[0] = RS5C348_CMD_R(RS5C348_REG_CTL2); /* cmd, ctl2 */ |
109 | txbuf[1] = 0; /* dummy */ |
110 | txbuf[2] = RS5C348_CMD_R(RS5C348_REG_CTL2); /* cmd, ctl2 */ |
111 | txbuf[3] = 0; /* dummy */ |
112 | txbuf[4] = RS5C348_CMD_MR(RS5C348_REG_SECS); /* cmd, sec, ... */ |
113 | |
114 | /* read in one transfer to avoid data inconsistency */ |
115 | ret = spi_write_then_read(spi, txbuf, sizeof(txbuf), |
116 | rxbuf, sizeof(rxbuf)); |
117 | udelay(62); /* Tcsr 62us */ |
118 | if (ret < 0) |
119 | return ret; |
120 | |
121 | tm->tm_sec = bcd2bin(rxbuf[RS5C348_REG_SECS] & RS5C348_SECS_MASK); |
122 | tm->tm_min = bcd2bin(rxbuf[RS5C348_REG_MINS] & RS5C348_MINS_MASK); |
123 | tm->tm_hour = bcd2bin(rxbuf[RS5C348_REG_HOURS] & RS5C348_HOURS_MASK); |
124 | if (!pdata->rtc_24h) { |
125 | if (rxbuf[RS5C348_REG_HOURS] & RS5C348_BIT_PM) { |
126 | tm->tm_hour -= 20; |
127 | tm->tm_hour %= 12; |
128 | tm->tm_hour += 12; |
129 | } else |
130 | tm->tm_hour %= 12; |
131 | } |
132 | tm->tm_wday = bcd2bin(rxbuf[RS5C348_REG_WDAY] & RS5C348_WDAY_MASK); |
133 | tm->tm_mday = bcd2bin(rxbuf[RS5C348_REG_DAY] & RS5C348_DAY_MASK); |
134 | tm->tm_mon = |
135 | bcd2bin(rxbuf[RS5C348_REG_MONTH] & RS5C348_MONTH_MASK) - 1; |
136 | /* year is 1900 + tm->tm_year */ |
137 | tm->tm_year = bcd2bin(rxbuf[RS5C348_REG_YEAR]) + |
138 | ((rxbuf[RS5C348_REG_MONTH] & RS5C348_BIT_Y2K) ? 100 : 0); |
139 | |
140 | if (rtc_valid_tm(tm) < 0) { |
141 | dev_err(&spi->dev, "retrieved date/time is not valid.\n"); |
142 | rtc_time_to_tm(0, tm); |
143 | } |
144 | |
145 | return 0; |
146 | } |
147 | |
148 | static const struct rtc_class_ops rs5c348_rtc_ops = { |
149 | .read_time = rs5c348_rtc_read_time, |
150 | .set_time = rs5c348_rtc_set_time, |
151 | }; |
152 | |
153 | static struct spi_driver rs5c348_driver; |
154 | |
155 | static int rs5c348_probe(struct spi_device *spi) |
156 | { |
157 | int ret; |
158 | struct rtc_device *rtc; |
159 | struct rs5c348_plat_data *pdata; |
160 | |
161 | pdata = kzalloc(sizeof(struct rs5c348_plat_data), GFP_KERNEL); |
162 | if (!pdata) |
163 | return -ENOMEM; |
164 | spi->dev.platform_data = pdata; |
165 | |
166 | /* Check D7 of SECOND register */ |
167 | ret = spi_w8r8(spi, RS5C348_CMD_R(RS5C348_REG_SECS)); |
168 | if (ret < 0 || (ret & 0x80)) { |
169 | dev_err(&spi->dev, "not found.\n"); |
170 | goto kfree_exit; |
171 | } |
172 | |
173 | dev_info(&spi->dev, "chip found, driver version " DRV_VERSION "\n"); |
174 | dev_info(&spi->dev, "spiclk %u KHz.\n", |
175 | (spi->max_speed_hz + 500) / 1000); |
176 | |
177 | /* turn RTC on if it was not on */ |
178 | ret = spi_w8r8(spi, RS5C348_CMD_R(RS5C348_REG_CTL2)); |
179 | if (ret < 0) |
180 | goto kfree_exit; |
181 | if (ret & (RS5C348_BIT_XSTP | RS5C348_BIT_VDET)) { |
182 | u8 buf[2]; |
183 | struct rtc_time tm; |
184 | if (ret & RS5C348_BIT_VDET) |
185 | dev_warn(&spi->dev, "voltage-low detected.\n"); |
186 | if (ret & RS5C348_BIT_XSTP) |
187 | dev_warn(&spi->dev, "oscillator-stop detected.\n"); |
188 | rtc_time_to_tm(0, &tm); /* 1970/1/1 */ |
189 | ret = rs5c348_rtc_set_time(&spi->dev, &tm); |
190 | if (ret < 0) |
191 | goto kfree_exit; |
192 | buf[0] = RS5C348_CMD_W(RS5C348_REG_CTL2); |
193 | buf[1] = 0; |
194 | ret = spi_write_then_read(spi, buf, sizeof(buf), NULL, 0); |
195 | if (ret < 0) |
196 | goto kfree_exit; |
197 | } |
198 | |
199 | ret = spi_w8r8(spi, RS5C348_CMD_R(RS5C348_REG_CTL1)); |
200 | if (ret < 0) |
201 | goto kfree_exit; |
202 | if (ret & RS5C348_BIT_24H) |
203 | pdata->rtc_24h = 1; |
204 | |
205 | rtc = rtc_device_register(rs5c348_driver.driver.name, &spi->dev, |
206 | &rs5c348_rtc_ops, THIS_MODULE); |
207 | |
208 | if (IS_ERR(rtc)) { |
209 | ret = PTR_ERR(rtc); |
210 | goto kfree_exit; |
211 | } |
212 | |
213 | pdata->rtc = rtc; |
214 | |
215 | return 0; |
216 | kfree_exit: |
217 | kfree(pdata); |
218 | return ret; |
219 | } |
220 | |
221 | static int rs5c348_remove(struct spi_device *spi) |
222 | { |
223 | struct rs5c348_plat_data *pdata = spi->dev.platform_data; |
224 | struct rtc_device *rtc = pdata->rtc; |
225 | |
226 | if (rtc) |
227 | rtc_device_unregister(rtc); |
228 | kfree(pdata); |
229 | return 0; |
230 | } |
231 | |
232 | static struct spi_driver rs5c348_driver = { |
233 | .driver = { |
234 | .name = "rtc-rs5c348", |
235 | .owner = THIS_MODULE, |
236 | }, |
237 | .probe = rs5c348_probe, |
238 | .remove = rs5c348_remove, |
239 | }; |
240 | |
241 | module_spi_driver(rs5c348_driver); |
242 | |
243 | MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>"); |
244 | MODULE_DESCRIPTION("Ricoh RS5C348 RTC driver"); |
245 | MODULE_LICENSE("GPL"); |
246 | MODULE_VERSION(DRV_VERSION); |
247 | MODULE_ALIAS("spi:rtc-rs5c348"); |
248 |
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