124 lines
3.1 KiB
C
124 lines
3.1 KiB
C
/*
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* Driver for ST M41T94 SPI RTC
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*
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* Taken from the Linux kernel drivier:
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* Copyright (C) 2008 Kim B. Heino
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*
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* Adaptation for U-Boot:
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* Copyright (C) 2009
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* Albin Tonnerre, Free Electrons <albin.tonnerre@free-electrons.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <common.h>
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#include <rtc.h>
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#include <spi.h>
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static struct spi_slave *slave;
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#define M41T94_REG_SECONDS 0x01
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#define M41T94_REG_MINUTES 0x02
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#define M41T94_REG_HOURS 0x03
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#define M41T94_REG_WDAY 0x04
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#define M41T94_REG_DAY 0x05
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#define M41T94_REG_MONTH 0x06
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#define M41T94_REG_YEAR 0x07
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#define M41T94_REG_HT 0x0c
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#define M41T94_BIT_HALT 0x40
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#define M41T94_BIT_STOP 0x80
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#define M41T94_BIT_CB 0x40
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#define M41T94_BIT_CEB 0x80
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int rtc_set(struct rtc_time *tm)
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{
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u8 buf[8]; /* write cmd + 7 registers */
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int ret;
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if (!slave) {
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slave = spi_setup_slave(CONFIG_M41T94_SPI_BUS,
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CONFIG_M41T94_SPI_CS, 1000000,
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SPI_MODE_3);
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if (!slave)
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return -1;
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}
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spi_claim_bus(slave);
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buf[0] = 0x80 | M41T94_REG_SECONDS; /* write time + date */
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buf[M41T94_REG_SECONDS] = bin2bcd(tm->tm_sec);
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buf[M41T94_REG_MINUTES] = bin2bcd(tm->tm_min);
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buf[M41T94_REG_HOURS] = bin2bcd(tm->tm_hour);
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buf[M41T94_REG_WDAY] = bin2bcd(tm->tm_wday + 1);
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buf[M41T94_REG_DAY] = bin2bcd(tm->tm_mday);
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buf[M41T94_REG_MONTH] = bin2bcd(tm->tm_mon + 1);
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buf[M41T94_REG_HOURS] |= M41T94_BIT_CEB;
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if (tm->tm_year >= 100)
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buf[M41T94_REG_HOURS] |= M41T94_BIT_CB;
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buf[M41T94_REG_YEAR] = bin2bcd(tm->tm_year % 100);
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ret = spi_xfer(slave, 64, buf, NULL, SPI_XFER_BEGIN | SPI_XFER_END);
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spi_release_bus(slave);
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return ret;
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}
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int rtc_get(struct rtc_time *tm)
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{
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u8 buf[2];
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int ret, hour;
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if (!slave) {
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slave = spi_setup_slave(CONFIG_M41T94_SPI_BUS,
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CONFIG_M41T94_SPI_CS, 1000000,
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SPI_MODE_3);
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if (!slave)
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return -1;
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}
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spi_claim_bus(slave);
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/* clear halt update bit */
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ret = spi_w8r8(slave, M41T94_REG_HT);
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if (ret < 0)
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return ret;
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if (ret & M41T94_BIT_HALT) {
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buf[0] = 0x80 | M41T94_REG_HT;
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buf[1] = ret & ~M41T94_BIT_HALT;
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spi_xfer(slave, 16, buf, NULL, SPI_XFER_BEGIN | SPI_XFER_END);
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}
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/* clear stop bit */
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ret = spi_w8r8(slave, M41T94_REG_SECONDS);
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if (ret < 0)
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return ret;
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if (ret & M41T94_BIT_STOP) {
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buf[0] = 0x80 | M41T94_REG_SECONDS;
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buf[1] = ret & ~M41T94_BIT_STOP;
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spi_xfer(slave, 16, buf, NULL, SPI_XFER_BEGIN | SPI_XFER_END);
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}
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tm->tm_sec = bcd2bin(spi_w8r8(slave, M41T94_REG_SECONDS));
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tm->tm_min = bcd2bin(spi_w8r8(slave, M41T94_REG_MINUTES));
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hour = spi_w8r8(slave, M41T94_REG_HOURS);
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tm->tm_hour = bcd2bin(hour & 0x3f);
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tm->tm_wday = bcd2bin(spi_w8r8(slave, M41T94_REG_WDAY)) - 1;
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tm->tm_mday = bcd2bin(spi_w8r8(slave, M41T94_REG_DAY));
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tm->tm_mon = bcd2bin(spi_w8r8(slave, M41T94_REG_MONTH)) - 1;
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tm->tm_year = bcd2bin(spi_w8r8(slave, M41T94_REG_YEAR));
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if ((hour & M41T94_BIT_CB) || !(hour & M41T94_BIT_CEB))
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tm->tm_year += 100;
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spi_release_bus(slave);
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return 0;
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}
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void rtc_reset(void)
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{
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/*
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* Could not be tested as the reset pin is not wired on
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* the sbc35-ag20 board
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*/
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}
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