AT91: add RTT and GPBR based RTC
Signed-off-by: Reinhard Meyer <u-boot@emk-elektronik.de>
diff --git a/drivers/rtc/at91sam9_rtt.c b/drivers/rtc/at91sam9_rtt.c
new file mode 100644
index 0000000..de8e30d
--- /dev/null
+++ b/drivers/rtc/at91sam9_rtt.c
@@ -0,0 +1,100 @@
+/*
+ * (C) Copyright 2010
+ * Reinhard Meyer, reinhard.meyer@emk-elektronik.de
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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
+ */
+
+/*
+ * Date & Time support for the internal Real-time Timer
+ * of AT91SAM9260 and compatibles.
+ * Compatible with the LinuX rtc driver workaround:
+ * The RTT cannot be written to, but only reset.
+ * The actual time is the sum of RTT and one of
+ * the four GPBR registers.
+ *
+ * The at91sam9260 has 4 GPBR (0-3).
+ * For their typical use see at91_gpbr.h !
+ *
+ * make sure u-boot and kernel use the same GPBR !
+ */
+
+#include <common.h>
+#include <command.h>
+#include <rtc.h>
+#include <asm/errno.h>
+#include <asm/arch/hardware.h>
+#include <asm/arch/io.h>
+#include <asm/arch/at91_rtt.h>
+#include <asm/arch/at91_gpbr.h>
+
+#if defined(CONFIG_CMD_DATE)
+
+int rtc_get (struct rtc_time *tmp)
+{
+ at91_rtt_t *rtt = (at91_rtt_t *) AT91_RTT_BASE;
+ at91_gpbr_t *gpbr = (at91_gpbr_t *) AT91_GPR_BASE;
+ ulong tim;
+ ulong tim2;
+ ulong off;
+
+ do {
+ tim = readl(&rtt->vr);
+ tim2 = readl(&rtt->vr);
+ } while (tim!=tim2);
+ off = readl(&gpbr->reg[AT91_GPBR_INDEX_TIMEOFF]);
+ /* off==0 means time is invalid, but we ignore that */
+ to_tm (tim+off, tmp);
+ return 0;
+}
+
+int rtc_set (struct rtc_time *tmp)
+{
+ at91_rtt_t *rtt = (at91_rtt_t *) AT91_RTT_BASE;
+ at91_gpbr_t *gpbr = (at91_gpbr_t *) AT91_GPR_BASE;
+ ulong tim;
+
+ tim = mktime (tmp->tm_year, tmp->tm_mon, tmp->tm_mday,
+ tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
+
+ /* clear alarm, set prescaler to 32768, clear counter */
+ writel(32768+AT91_RTT_RTTRST, &rtt->mr);
+ writel(~0, &rtt->ar);
+ writel(tim, &gpbr->reg[AT91_GPBR_INDEX_TIMEOFF]);
+ /* wait for counter clear to happen, takes less than a 1/32768th second */
+ while (readl(&rtt->vr) != 0)
+ ;
+ return 0;
+}
+
+void rtc_reset (void)
+{
+ at91_rtt_t *rtt = (at91_rtt_t *) AT91_RTT_BASE;
+ at91_gpbr_t *gpbr = (at91_gpbr_t *) AT91_GPR_BASE;
+
+ /* clear alarm, set prescaler to 32768, clear counter */
+ writel(32768+AT91_RTT_RTTRST, &rtt->mr);
+ writel(~0, &rtt->ar);
+ writel(0, &gpbr->reg[AT91_GPBR_INDEX_TIMEOFF]);
+ /* wait for counter clear to happen, takes less than a 1/32768th second */
+ while (readl(&rtt->vr) != 0)
+ ;
+}
+
+#endif