rk808: Implement RTC driver

This adds RTC functions to the existing RK808 driver.

BUG=chrome-os-partner:34436
BRANCH=none
TEST=with eventlog patches applied to pinky, booted and saw eventlog
entries generated with correct timestamps:
localhost ~ # mosys -k eventlog list
entry="0" timestamp="2015-01-06 13:45:33" type="Log area cleared" bytes="4096"
entry="1" timestamp="2015-01-06 13:45:33" type="System boot" count="0"
entry="2" timestamp="2015-01-06 13:45:33" type="Chrome OS Developer Mode"

Change-Id: I1df70a2ca94ff463ffea8d9f02d951d6c62e6b08
Signed-off-by: Stefan Reinauer <reinauer@chromium.org>
Original-Commit-Id: a304f7e6954f585f04feef54c4902dcb25a39fcc
Original-Signed-off-by: David Hendricks <dhendrix@chromium.org>
Original-Change-Id: I3a240e342a54b2e7023da71708d0d70f5131f0b9
Original-Reviewed-on: https://chromium-review.googlesource.com/238525
Original-Reviewed-by: Julius Werner <jwerner@chromium.org>
Original-Commit-Queue: Julius Werner <jwerner@chromium.org>
Original-Tested-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: http://review.coreboot.org/9643
Tested-by: build bot (Jenkins)
Reviewed-by: Marc Jones <marc.jones@se-eng.com>

1 files changed, 79 insertions, 0 deletions

diff --git a/src/soc/rockchip/rk3288/rk808.c b/src/soc/rockchip/rk3288/rk808.c
index de19a55135..b763454903 100644
--- a/src/soc/rockchip/rk3288/rk808.c
+++ b/src/soc/rockchip/rk3288/rk808.c
@@ -18,9 +18,11 @@
  */
 
 #include <assert.h>
+#include <bcd.h>
 #include <console/console.h>
 #include <delay.h>
 #include <device/i2c.h>
+#include <rtc.h>
 #include <soc/rk808.h>
 #include <stdint.h>
 #include <stdlib.h>
@@ -38,6 +40,20 @@
 #define LDO_ONSEL(i)		(0x39 + 2 * i)
 #define LDO_SLPSEL(i)		(0x3a + 2 * i)
 
+#define RTC_SECOND		0x00
+#define RTC_MINUTE		0x01
+#define RTC_HOUR		0x02
+#define RTC_DAY			0x03
+#define RTC_MONTH		0x04
+#define RTC_YEAR		0x05
+#define RTC_WEEKS		0x06
+#define RTC_CTRL		0x10
+#define RTC_STATUS		0x11
+
+#define RTC_CTRL_STOP_RTC	(1 << 0)
+#define RTC_CTRL_GET_TIME	(1 << 6)
+#define RTC_CTRL_RTC_READSEL	(1 << 7)
+
 static int rk808_read(uint8_t reg, uint8_t *value)
 {
 	return i2c_readb(CONFIG_PMIC_BUS, RK808_ADDR, reg, value);
@@ -118,3 +134,66 @@ void rk808_configure_buck(int buck, int millivolts)
 	rk808_clrsetbits(buck_reg, 0x3f, vsel);
 	rk808_clrsetbits(DCDC_EN, 0, 1 << (buck - 1));
 }
+
+static void rk808rtc_stop(void)
+{
+	rk808_clrsetbits(RTC_CTRL, RTC_CTRL_STOP_RTC, 0);
+}
+
+static void rk808rtc_start(void)
+{
+	rk808_clrsetbits(RTC_CTRL, 0, RTC_CTRL_STOP_RTC);
+}
+
+int rtc_set(const struct rtc_time *time)
+{
+	int ret = 0;
+
+	/* RTC time can only be set when RTC is frozen */
+	rk808rtc_stop();
+
+	ret |= rk808_write(RTC_SECOND, bin2bcd(time->sec));
+	ret |= rk808_write(RTC_MINUTE, bin2bcd(time->min));
+	ret |= rk808_write(RTC_HOUR, bin2bcd(time->hour));
+	ret |= rk808_write(RTC_DAY, bin2bcd(time->mday));
+	ret |= rk808_write(RTC_MONTH, bin2bcd(time->mon));
+	ret |= rk808_write(RTC_YEAR, bin2bcd(time->year));
+
+	rk808rtc_start();
+	return ret;
+}
+
+int rtc_get(struct rtc_time *time)
+{
+	uint8_t value;
+	int ret = 0;
+
+	/*
+	 * Set RTC_READSEL to cause reads to access shadow registers and
+	 * transition GET_TIME from 0 to 1 to cause dynamic register content
+	 * to be copied into shadow registers. This ensures a coherent reading
+	 * of time values as we access each register using slow I2C transfers.
+	 */
+	rk808_clrsetbits(RTC_CTRL, RTC_CTRL_GET_TIME, 0);
+	rk808_clrsetbits(RTC_CTRL, 0, RTC_CTRL_GET_TIME | RTC_CTRL_RTC_READSEL);
+
+	ret |= rk808_read(RTC_SECOND, &value);
+	time->sec = bcd2bin(value & 0x7f);
+
+	ret |= rk808_read(RTC_MINUTE, &value);
+	time->min = bcd2bin(value & 0x7f);
+
+	ret |= rk808_read(RTC_HOUR, &value);
+	time->hour = bcd2bin(value & 0x3f);
+
+	ret |= rk808_read(RTC_DAY, &value);
+	time->mday = bcd2bin(value & 0x3f);
+
+	ret |= rk808_read(RTC_MONTH, &value);
+	time->mon = bcd2bin(value & 0x1f);
+
+	ret |= rk808_read(RTC_YEAR, &value);
+	time->year = bcd2bin(value);
+
+	return ret;
+}