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6b8548b0 AT |
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 | ||
20 | static 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 | ||
36 | int 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 | ||
68 | int 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 | ||
117 | void rtc_reset(void) | |
118 | { | |
119 | /* | |
120 | * Could not be tested as the reset pin is not wired on | |
121 | * the sbc35-ag20 board | |
122 | */ | |
6b8548b0 | 123 | } |