iMX28: Add driver for internal RTC

Signed-off-by: Marek Vasut <marek.vasut@gmail.com>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Wolfgang Denk <wd@denx.de>
Cc: Detlev Zundel <dzu@denx.de>

drivers/rtc/Makefile

@@ -57,6 +57,7 @@ COBJS-$(CONFIG_RTC_MK48T59) += mk48t59.o
 COBJS-$(CONFIG_RTC_MPC5200) += mpc5xxx.o
 COBJS-$(CONFIG_RTC_MPC8xx) += mpc8xx.o
 COBJS-$(CONFIG_RTC_MV) += mvrtc.o
+COBJS-$(CONFIG_RTC_MXS) += mxsrtc.o
 COBJS-$(CONFIG_RTC_PCF8563) += pcf8563.o
 COBJS-$(CONFIG_RTC_PL031) += pl031.o
 COBJS-$(CONFIG_RTC_PT7C4338) += pt7c4338.o

drivers/rtc/mxsrtc.c

@@ -0,0 +1,86 @@
+/*
+ * Freescale i.MX28 RTC Driver
+ *
+ * Copyright (C) 2011 Marek Vasut <marek.vasut@gmail.com>
+ * on behalf of DENX Software Engineering GmbH
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
+ *
+ */
+
+#include <common.h>
+#include <rtc.h>
+#include <asm/io.h>
+#include <asm/arch/imx-regs.h>
+#include <asm/arch/sys_proto.h>
+
+#define	MXS_RTC_MAX_TIMEOUT	1000000
+
+/* Set time in seconds since 1970-01-01 */
+int mxs_rtc_set_time(uint32_t secs)
+{
+	struct mx28_rtc_regs *rtc_regs = (struct mx28_rtc_regs *)MXS_RTC_BASE;
+	int ret;
+
+	writel(secs, &rtc_regs->hw_rtc_seconds);
+
+	/*
+	 * The 0x80 here means seconds were copied to analog. This information
+	 * is taken from the linux kernel driver for the STMP37xx RTC since
+	 * documentation doesn't mention it.
+	 */
+	ret = mx28_wait_mask_clr(&rtc_regs->hw_rtc_stat_reg,
+		0x80 << RTC_STAT_STALE_REGS_OFFSET, MXS_RTC_MAX_TIMEOUT);
+
+	if (ret)
+		printf("MXS RTC: Timeout waiting for update\n");
+
+	return ret;
+}
+
+int rtc_get(struct rtc_time *time)
+{
+	struct mx28_rtc_regs *rtc_regs = (struct mx28_rtc_regs *)MXS_RTC_BASE;
+	uint32_t secs;
+
+	secs = readl(&rtc_regs->hw_rtc_seconds);
+	to_tm(secs, time);
+
+	return 0;
+}
+
+int rtc_set(struct rtc_time *time)
+{
+	uint32_t secs;
+
+	secs = mktime(time->tm_year, time->tm_mon, time->tm_mday,
+		time->tm_hour, time->tm_min, time->tm_sec);
+
+	return mxs_rtc_set_time(secs);
+}
+
+void rtc_reset(void)
+{
+	struct mx28_rtc_regs *rtc_regs = (struct mx28_rtc_regs *)MXS_RTC_BASE;
+	int ret;
+
+	/* Set time to 1970-01-01 */
+	mxs_rtc_set_time(0);
+
+	/* Reset the RTC block */
+	ret = mx28_reset_block(&rtc_regs->hw_rtc_ctrl_reg);
+	if (ret)
+		printf("MXS RTC: Block reset timeout\n");
+}