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path: root/drivers/rtc/rtc-rs5c348.c
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-rw-r--r--drivers/rtc/rtc-rs5c348.c246
1 files changed, 246 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-rs5c348.c b/drivers/rtc/rtc-rs5c348.c
new file mode 100644
index 000000000000..0964d1dba925
--- /dev/null
+++ b/drivers/rtc/rtc-rs5c348.c
@@ -0,0 +1,246 @@
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/rtc.h>
23#include <linux/workqueue.h>
24#include <linux/spi/spi.h>
25
26#define DRV_VERSION "0.1"
27
28#define RS5C348_REG_SECS 0
29#define RS5C348_REG_MINS 1
30#define RS5C348_REG_HOURS 2
31#define RS5C348_REG_WDAY 3
32#define RS5C348_REG_DAY 4
33#define RS5C348_REG_MONTH 5
34#define RS5C348_REG_YEAR 6
35#define RS5C348_REG_CTL1 14
36#define RS5C348_REG_CTL2 15
37
38#define RS5C348_SECS_MASK 0x7f
39#define RS5C348_MINS_MASK 0x7f
40#define RS5C348_HOURS_MASK 0x3f
41#define RS5C348_WDAY_MASK 0x03
42#define RS5C348_DAY_MASK 0x3f
43#define RS5C348_MONTH_MASK 0x1f
44
45#define RS5C348_BIT_PM 0x20 /* REG_HOURS */
46#define RS5C348_BIT_Y2K 0x80 /* REG_MONTH */
47#define RS5C348_BIT_24H 0x20 /* REG_CTL1 */
48#define RS5C348_BIT_XSTP 0x10 /* REG_CTL2 */
49#define RS5C348_BIT_VDET 0x40 /* REG_CTL2 */
50
51#define RS5C348_CMD_W(addr) (((addr) << 4) | 0x08) /* single write */
52#define RS5C348_CMD_R(addr) (((addr) << 4) | 0x0c) /* single read */
53#define RS5C348_CMD_MW(addr) (((addr) << 4) | 0x00) /* burst write */
54#define RS5C348_CMD_MR(addr) (((addr) << 4) | 0x04) /* burst read */
55
56struct rs5c348_plat_data {
57 struct rtc_device *rtc;
58 int rtc_24h;
59};
60
61static int
62rs5c348_rtc_set_time(struct device *dev, struct rtc_time *tm)
63{
64 struct spi_device *spi = to_spi_device(dev);
65 struct rs5c348_plat_data *pdata = spi->dev.platform_data;
66 u8 txbuf[5+7], *txp;
67 int ret;
68
69 /* Transfer 5 bytes before writing SEC. This gives 31us for carry. */
70 txp = txbuf;
71 txbuf[0] = RS5C348_CMD_R(RS5C348_REG_CTL2); /* cmd, ctl2 */
72 txbuf[1] = 0; /* dummy */
73 txbuf[2] = RS5C348_CMD_R(RS5C348_REG_CTL2); /* cmd, ctl2 */
74 txbuf[3] = 0; /* dummy */
75 txbuf[4] = RS5C348_CMD_MW(RS5C348_REG_SECS); /* cmd, sec, ... */
76 txp = &txbuf[5];
77 txp[RS5C348_REG_SECS] = BIN2BCD(tm->tm_sec);
78 txp[RS5C348_REG_MINS] = BIN2BCD(tm->tm_min);
79 if (pdata->rtc_24h) {
80 txp[RS5C348_REG_HOURS] = BIN2BCD(tm->tm_hour);
81 } else {
82 /* hour 0 is AM12, noon is PM12 */
83 txp[RS5C348_REG_HOURS] = BIN2BCD((tm->tm_hour + 11) % 12 + 1) |
84 (tm->tm_hour >= 12 ? RS5C348_BIT_PM : 0);
85 }
86 txp[RS5C348_REG_WDAY] = BIN2BCD(tm->tm_wday);
87 txp[RS5C348_REG_DAY] = BIN2BCD(tm->tm_mday);
88 txp[RS5C348_REG_MONTH] = BIN2BCD(tm->tm_mon + 1) |
89 (tm->tm_year >= 100 ? RS5C348_BIT_Y2K : 0);
90 txp[RS5C348_REG_YEAR] = BIN2BCD(tm->tm_year % 100);
91 /* write in one transfer to avoid data inconsistency */
92 ret = spi_write_then_read(spi, txbuf, sizeof(txbuf), NULL, 0);
93 udelay(62); /* Tcsr 62us */
94 return ret;
95}
96
97static int
98rs5c348_rtc_read_time(struct device *dev, struct rtc_time *tm)
99{
100 struct spi_device *spi = to_spi_device(dev);
101 struct rs5c348_plat_data *pdata = spi->dev.platform_data;
102 u8 txbuf[5], rxbuf[7];
103 int ret;
104
105 /* Transfer 5 byte befores reading SEC. This gives 31us for carry. */
106 txbuf[0] = RS5C348_CMD_R(RS5C348_REG_CTL2); /* cmd, ctl2 */
107 txbuf[1] = 0; /* dummy */
108 txbuf[2] = RS5C348_CMD_R(RS5C348_REG_CTL2); /* cmd, ctl2 */
109 txbuf[3] = 0; /* dummy */
110 txbuf[4] = RS5C348_CMD_MR(RS5C348_REG_SECS); /* cmd, sec, ... */
111
112 /* read in one transfer to avoid data inconsistency */
113 ret = spi_write_then_read(spi, txbuf, sizeof(txbuf),
114 rxbuf, sizeof(rxbuf));
115 udelay(62); /* Tcsr 62us */
116 if (ret < 0)
117 return ret;
118
119 tm->tm_sec = BCD2BIN(rxbuf[RS5C348_REG_SECS] & RS5C348_SECS_MASK);
120 tm->tm_min = BCD2BIN(rxbuf[RS5C348_REG_MINS] & RS5C348_MINS_MASK);
121 tm->tm_hour = BCD2BIN(rxbuf[RS5C348_REG_HOURS] & RS5C348_HOURS_MASK);
122 if (!pdata->rtc_24h) {
123 tm->tm_hour %= 12;
124 if (rxbuf[RS5C348_REG_HOURS] & RS5C348_BIT_PM)
125 tm->tm_hour += 12;
126 }
127 tm->tm_wday = BCD2BIN(rxbuf[RS5C348_REG_WDAY] & RS5C348_WDAY_MASK);
128 tm->tm_mday = BCD2BIN(rxbuf[RS5C348_REG_DAY] & RS5C348_DAY_MASK);
129 tm->tm_mon =
130 BCD2BIN(rxbuf[RS5C348_REG_MONTH] & RS5C348_MONTH_MASK) - 1;
131 /* year is 1900 + tm->tm_year */
132 tm->tm_year = BCD2BIN(rxbuf[RS5C348_REG_YEAR]) +
133 ((rxbuf[RS5C348_REG_MONTH] & RS5C348_BIT_Y2K) ? 100 : 0);
134
135 if (rtc_valid_tm(tm) < 0) {
136 dev_err(&spi->dev, "retrieved date/time is not valid.\n");
137 rtc_time_to_tm(0, tm);
138 }
139
140 return 0;
141}
142
143static struct rtc_class_ops rs5c348_rtc_ops = {
144 .read_time = rs5c348_rtc_read_time,
145 .set_time = rs5c348_rtc_set_time,
146};
147
148static struct spi_driver rs5c348_driver;
149
150static int __devinit rs5c348_probe(struct spi_device *spi)
151{
152 int ret;
153 struct rtc_device *rtc;
154 struct rs5c348_plat_data *pdata;
155
156 pdata = kzalloc(sizeof(struct rs5c348_plat_data), GFP_KERNEL);
157 if (!pdata)
158 return -ENOMEM;
159 spi->dev.platform_data = pdata;
160
161 /* Check D7 of SECOND register */
162 ret = spi_w8r8(spi, RS5C348_CMD_R(RS5C348_REG_SECS));
163 if (ret < 0 || (ret & 0x80)) {
164 dev_err(&spi->dev, "not found.\n");
165 goto kfree_exit;
166 }
167
168 dev_info(&spi->dev, "chip found, driver version " DRV_VERSION "\n");
169 dev_info(&spi->dev, "spiclk %u KHz.\n",
170 (spi->max_speed_hz + 500) / 1000);
171
172 /* turn RTC on if it was not on */
173 ret = spi_w8r8(spi, RS5C348_CMD_R(RS5C348_REG_CTL2));
174 if (ret < 0)
175 goto kfree_exit;
176 if (ret & (RS5C348_BIT_XSTP | RS5C348_BIT_VDET)) {
177 u8 buf[2];
178 if (ret & RS5C348_BIT_VDET)
179 dev_warn(&spi->dev, "voltage-low detected.\n");
180 buf[0] = RS5C348_CMD_W(RS5C348_REG_CTL2);
181 buf[1] = 0;
182 ret = spi_write_then_read(spi, buf, sizeof(buf), NULL, 0);
183 if (ret < 0)
184 goto kfree_exit;
185 }
186
187 ret = spi_w8r8(spi, RS5C348_CMD_R(RS5C348_REG_CTL1));
188 if (ret < 0)
189 goto kfree_exit;
190 if (ret & RS5C348_BIT_24H)
191 pdata->rtc_24h = 1;
192
193 rtc = rtc_device_register(rs5c348_driver.driver.name, &spi->dev,
194 &rs5c348_rtc_ops, THIS_MODULE);
195
196 if (IS_ERR(rtc)) {
197 ret = PTR_ERR(rtc);
198 goto kfree_exit;
199 }
200
201 pdata->rtc = rtc;
202
203 return 0;
204 kfree_exit:
205 kfree(pdata);
206 return ret;
207}
208
209static int __devexit rs5c348_remove(struct spi_device *spi)
210{
211 struct rs5c348_plat_data *pdata = spi->dev.platform_data;
212 struct rtc_device *rtc = pdata->rtc;
213
214 if (rtc)
215 rtc_device_unregister(rtc);
216 kfree(pdata);
217 return 0;
218}
219
220static struct spi_driver rs5c348_driver = {
221 .driver = {
222 .name = "rs5c348",
223 .bus = &spi_bus_type,
224 .owner = THIS_MODULE,
225 },
226 .probe = rs5c348_probe,
227 .remove = __devexit_p(rs5c348_remove),
228};
229
230static __init int rs5c348_init(void)
231{
232 return spi_register_driver(&rs5c348_driver);
233}
234
235static __exit void rs5c348_exit(void)
236{
237 spi_unregister_driver(&rs5c348_driver);
238}
239
240module_init(rs5c348_init);
241module_exit(rs5c348_exit);
242
243MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
244MODULE_DESCRIPTION("Ricoh RS5C348 RTC driver");
245MODULE_LICENSE("GPL");
246MODULE_VERSION(DRV_VERSION);
generated by cgit v1.2.2 (git 2.25.0) at 2025-10-27 05:51:14 -0400