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authorAlbin Tonnerre <albin.tonnerre@free-electrons.com>2009-08-13 19:12:44 +0200
committerWolfgang Denk <wd@denx.de>2009-08-25 12:57:55 +0200
commit6b8548b0f7068379ad1efa4fa28725f361b2d3cd (patch)
tree6d71ad5a8d899acad0be594fe9f3e839d7859d93
parent885fc78c28fbe773bcb4edc9dd0fdac05ebb5b38 (diff)
Add driver for the ST M41T94 SPI RTC
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>
-rw-r--r--drivers/rtc/Makefile1
-rw-r--r--drivers/rtc/m41t94.c124
2 files changed, 125 insertions, 0 deletions
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 822dc1a0e1..ea7d899ea9 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 0000000000..02b41d91b1
--- /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;
+}