This RTC is used in some Calao boards. The driver code is taken from the linux rtc-m41t94 driver
Signed-off-by: Albin Tonnerre albin.tonnerre@free-electrons.com --- Changelog since V1: - Use the common bin2bcd/bcd2bin functions. This patch depends on: 1250170272-25909-2-git-send-email-albin.tonnerre@free-electrons.com
drivers/rtc/Makefile | 1 + drivers/rtc/m41t94.c | 124 ++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 125 insertions(+), 0 deletions(-) create mode 100644 drivers/rtc/m41t94.c
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile index 822dc1a..ea7d899 100644 --- a/drivers/rtc/Makefile +++ b/drivers/rtc/Makefile @@ -44,6 +44,7 @@ COBJS-$(CONFIG_RTC_ISL1208) += isl1208.o COBJS-$(CONFIG_RTC_M41T11) += m41t11.o COBJS-$(CONFIG_RTC_M41T60) += m41t60.o COBJS-$(CONFIG_RTC_M41T62) += m41t62.o +COBJS-$(CONFIG_RTC_M41T94) += m41t94.o COBJS-$(CONFIG_RTC_M48T35A) += m48t35ax.o COBJS-$(CONFIG_RTC_MAX6900) += max6900.o COBJS-$(CONFIG_RTC_MC13783) += mc13783-rtc.o diff --git a/drivers/rtc/m41t94.c b/drivers/rtc/m41t94.c new file mode 100644 index 0000000..02b41d9 --- /dev/null +++ b/drivers/rtc/m41t94.c @@ -0,0 +1,124 @@ +/* + * Driver for ST M41T94 SPI RTC + * + * Taken from the Linux kernel drivier: + * Copyright (C) 2008 Kim B. Heino + * + * Adaptation for U-Boot: + * Copyright (C) 2009 + * Albin Tonnerre, Free Electrons albin.tonnerre@free-electrons.com + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <common.h> +#include <rtc.h> +#include <spi.h> + +static struct spi_slave *slave; + +#define M41T94_REG_SECONDS 0x01 +#define M41T94_REG_MINUTES 0x02 +#define M41T94_REG_HOURS 0x03 +#define M41T94_REG_WDAY 0x04 +#define M41T94_REG_DAY 0x05 +#define M41T94_REG_MONTH 0x06 +#define M41T94_REG_YEAR 0x07 +#define M41T94_REG_HT 0x0c + +#define M41T94_BIT_HALT 0x40 +#define M41T94_BIT_STOP 0x80 +#define M41T94_BIT_CB 0x40 +#define M41T94_BIT_CEB 0x80 + +int rtc_set(struct rtc_time *tm) +{ + u8 buf[8]; /* write cmd + 7 registers */ + int ret; + + if (!slave) { + slave = spi_setup_slave(CONFIG_M41T94_SPI_BUS, + CONFIG_M41T94_SPI_CS, 1000000, + SPI_MODE_3); + if (!slave) + return -1; + } + spi_claim_bus(slave); + + buf[0] = 0x80 | M41T94_REG_SECONDS; /* write time + date */ + buf[M41T94_REG_SECONDS] = bin2bcd(tm->tm_sec); + buf[M41T94_REG_MINUTES] = bin2bcd(tm->tm_min); + buf[M41T94_REG_HOURS] = bin2bcd(tm->tm_hour); + buf[M41T94_REG_WDAY] = bin2bcd(tm->tm_wday + 1); + buf[M41T94_REG_DAY] = bin2bcd(tm->tm_mday); + buf[M41T94_REG_MONTH] = bin2bcd(tm->tm_mon + 1); + + buf[M41T94_REG_HOURS] |= M41T94_BIT_CEB; + if (tm->tm_year >= 100) + buf[M41T94_REG_HOURS] |= M41T94_BIT_CB; + buf[M41T94_REG_YEAR] = bin2bcd(tm->tm_year % 100); + + ret = spi_xfer(slave, 64, buf, NULL, SPI_XFER_BEGIN | SPI_XFER_END); + spi_release_bus(slave); + return ret; +} + +int rtc_get(struct rtc_time *tm) +{ + u8 buf[2]; + int ret, hour; + + if (!slave) { + slave = spi_setup_slave(CONFIG_M41T94_SPI_BUS, + CONFIG_M41T94_SPI_CS, 1000000, + SPI_MODE_3); + if (!slave) + return -1; + } + spi_claim_bus(slave); + + /* clear halt update bit */ + ret = spi_w8r8(slave, M41T94_REG_HT); + if (ret < 0) + return ret; + if (ret & M41T94_BIT_HALT) { + buf[0] = 0x80 | M41T94_REG_HT; + buf[1] = ret & ~M41T94_BIT_HALT; + spi_xfer(slave, 16, buf, NULL, SPI_XFER_BEGIN | SPI_XFER_END); + } + + /* clear stop bit */ + ret = spi_w8r8(slave, M41T94_REG_SECONDS); + if (ret < 0) + return ret; + if (ret & M41T94_BIT_STOP) { + buf[0] = 0x80 | M41T94_REG_SECONDS; + buf[1] = ret & ~M41T94_BIT_STOP; + spi_xfer(slave, 16, buf, NULL, SPI_XFER_BEGIN | SPI_XFER_END); + } + + tm->tm_sec = bcd2bin(spi_w8r8(slave, M41T94_REG_SECONDS)); + tm->tm_min = bcd2bin(spi_w8r8(slave, M41T94_REG_MINUTES)); + hour = spi_w8r8(slave, M41T94_REG_HOURS); + tm->tm_hour = bcd2bin(hour & 0x3f); + tm->tm_wday = bcd2bin(spi_w8r8(slave, M41T94_REG_WDAY)) - 1; + tm->tm_mday = bcd2bin(spi_w8r8(slave, M41T94_REG_DAY)); + tm->tm_mon = bcd2bin(spi_w8r8(slave, M41T94_REG_MONTH)) - 1; + tm->tm_year = bcd2bin(spi_w8r8(slave, M41T94_REG_YEAR)); + if ((hour & M41T94_BIT_CB) || !(hour & M41T94_BIT_CEB)) + tm->tm_year += 100; + + spi_release_bus(slave); + return 0; +} + +void rtc_reset(void) +{ + /* + * Could not be tested as the reset pin is not wired on + * the sbc35-ag20 board + */ + return 0; +}