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gerrit.devboardsforandroid.linaro.org / platform / external / u-boot / 0d042037b3cf8693ea0f793d0c292430bfc5a95c / . / drivers / rtc / m41t94.c
blob: 02b41d91b1ac29f95a550b6ea17c18747e210e0c [file] [log] [blame]
Albin Tonnerre6b8548b2009-08-13 19:12:44 +0200[diff] [blame]1/*
2 * Driver for ST M41T94 SPI RTC
3 *
4 * Taken from the Linux kernel drivier:
5 * Copyright (C) 2008 Kim B. Heino
6 *
7 * Adaptation for U-Boot:
8 * Copyright (C) 2009
9 * Albin Tonnerre, Free Electrons <albin.tonnerre@free-electrons.com>
10 *
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License version 2 as
13 * published by the Free Software Foundation.
14 */
15
16#include <common.h>
17#include <rtc.h>
18#include <spi.h>
19
20static struct spi_slave *slave;
21
22#define M41T94_REG_SECONDS 0x01
23#define M41T94_REG_MINUTES 0x02
24#define M41T94_REG_HOURS 0x03
25#define M41T94_REG_WDAY 0x04
26#define M41T94_REG_DAY 0x05
27#define M41T94_REG_MONTH 0x06
28#define M41T94_REG_YEAR 0x07
29#define M41T94_REG_HT 0x0c
30
31#define M41T94_BIT_HALT 0x40
32#define M41T94_BIT_STOP 0x80
33#define M41T94_BIT_CB 0x40
34#define M41T94_BIT_CEB 0x80
35
36int rtc_set(struct rtc_time *tm)
37{
38 u8 buf[8]; /* write cmd + 7 registers */
39 int ret;
40
41 if (!slave) {
42 slave = spi_setup_slave(CONFIG_M41T94_SPI_BUS,
43 CONFIG_M41T94_SPI_CS, 1000000,
44 SPI_MODE_3);
45 if (!slave)
46 return -1;
47 }
48 spi_claim_bus(slave);
49
50 buf[0] = 0x80 | M41T94_REG_SECONDS; /* write time + date */
51 buf[M41T94_REG_SECONDS] = bin2bcd(tm->tm_sec);
52 buf[M41T94_REG_MINUTES] = bin2bcd(tm->tm_min);
53 buf[M41T94_REG_HOURS] = bin2bcd(tm->tm_hour);
54 buf[M41T94_REG_WDAY] = bin2bcd(tm->tm_wday + 1);
55 buf[M41T94_REG_DAY] = bin2bcd(tm->tm_mday);
56 buf[M41T94_REG_MONTH] = bin2bcd(tm->tm_mon + 1);
57
58 buf[M41T94_REG_HOURS] |= M41T94_BIT_CEB;
59 if (tm->tm_year >= 100)
60 buf[M41T94_REG_HOURS] |= M41T94_BIT_CB;
61 buf[M41T94_REG_YEAR] = bin2bcd(tm->tm_year % 100);
62
63 ret = spi_xfer(slave, 64, buf, NULL, SPI_XFER_BEGIN | SPI_XFER_END);
64 spi_release_bus(slave);
65 return ret;
66}
67
68int rtc_get(struct rtc_time *tm)
69{
70 u8 buf[2];
71 int ret, hour;
72
73 if (!slave) {
74 slave = spi_setup_slave(CONFIG_M41T94_SPI_BUS,
75 CONFIG_M41T94_SPI_CS, 1000000,
76 SPI_MODE_3);
77 if (!slave)
78 return -1;
79 }
80 spi_claim_bus(slave);
81
82 /* clear halt update bit */
83 ret = spi_w8r8(slave, M41T94_REG_HT);
84 if (ret < 0)
85 return ret;
86 if (ret & M41T94_BIT_HALT) {
87 buf[0] = 0x80 | M41T94_REG_HT;
88 buf[1] = ret & ~M41T94_BIT_HALT;
89 spi_xfer(slave, 16, buf, NULL, SPI_XFER_BEGIN | SPI_XFER_END);
90 }
91
92 /* clear stop bit */
93 ret = spi_w8r8(slave, M41T94_REG_SECONDS);
94 if (ret < 0)
95 return ret;
96 if (ret & M41T94_BIT_STOP) {
97 buf[0] = 0x80 | M41T94_REG_SECONDS;
98 buf[1] = ret & ~M41T94_BIT_STOP;
99 spi_xfer(slave, 16, buf, NULL, SPI_XFER_BEGIN | SPI_XFER_END);
100 }
101
102 tm->tm_sec = bcd2bin(spi_w8r8(slave, M41T94_REG_SECONDS));
103 tm->tm_min = bcd2bin(spi_w8r8(slave, M41T94_REG_MINUTES));
104 hour = spi_w8r8(slave, M41T94_REG_HOURS);
105 tm->tm_hour = bcd2bin(hour & 0x3f);
106 tm->tm_wday = bcd2bin(spi_w8r8(slave, M41T94_REG_WDAY)) - 1;
107 tm->tm_mday = bcd2bin(spi_w8r8(slave, M41T94_REG_DAY));
108 tm->tm_mon = bcd2bin(spi_w8r8(slave, M41T94_REG_MONTH)) - 1;
109 tm->tm_year = bcd2bin(spi_w8r8(slave, M41T94_REG_YEAR));
110 if ((hour & M41T94_BIT_CB) || !(hour & M41T94_BIT_CEB))
111 tm->tm_year += 100;
112
113 spi_release_bus(slave);
114 return 0;
115}
116
117void rtc_reset(void)
118{
119 /*
120 * Could not be tested as the reset pin is not wired on
121 * the sbc35-ag20 board
122 */
123 return 0;
124}