rtc: add Microcrystal RV-8803 driver

Signed-off-by: Michael Walle <michael@walle.cc>

3 files changed, 178 insertions, 0 deletions

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index fd0009b..532e94d 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -70,6 +70,16 @@ config RTC_RV3029
 	  This driver supports reading and writing the RTC/calendar and the
 	  battery-baced SRAM section.
 
+config RTC_RV8803
+	bool "Enable RV8803 driver"
+	depends on DM_RTC
+	help
+	  The Micro Crystal RV8803 is a high accuracy, ultra-low power I2C
+	  Real Time Clock (RTC) with temperature compensation.
+
+	  This driver supports reading and writing the RTC/calendar and
+	  detects total power failures.
+
 config RTC_RX8010SJ
 	bool "Enable RX8010SJ driver"
 	depends on DM_RTC
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 1724602..915adb8 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -46,6 +46,7 @@ obj-$(CONFIG_RTC_PL031) += pl031.o
 obj-$(CONFIG_RTC_PT7C4338) += pt7c4338.o
 obj-$(CONFIG_RTC_RS5C372A) += rs5c372.o
 obj-$(CONFIG_RTC_RV3029) += rv3029.o
+obj-$(CONFIG_RTC_RV8803) += rv8803.o
 obj-$(CONFIG_RTC_RX8025) += rx8025.o
 obj-$(CONFIG_RTC_RX8010SJ) += rx8010sj.o
 obj-$(CONFIG_RTC_S3C24X0) += s3c24x0_rtc.o
diff --git a/drivers/rtc/rv8803.c b/drivers/rtc/rv8803.c
new file mode 100644
index 0000000..2ab40f0
--- /dev/null
+++ b/drivers/rtc/rv8803.c
@@ -0,0 +1,167 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Date & Time support for Micro Crystal RV-8803-C7.
+ *
+ * based on ds1307.c which is
+ *   (C) Copyright 2001, 2002, 2003
+ *   Wolfgang Denk, DENX Software Engineering, wd@denx.de.
+ *   Keith Outwater, keith_outwater@mvis.com`
+ *   Steven Scholz, steven.scholz@imc-berlin.de
+ *
+ */
+
+#include <common.h>
+#include <command.h>
+#include <dm.h>
+#include <rtc.h>
+#include <i2c.h>
+
+/*
+ * RTC register addresses
+ */
+#define RTC_SEC_REG_ADDR	0x00
+#define RTC_MIN_REG_ADDR	0x01
+#define RTC_HR_REG_ADDR		0x02
+#define RTC_DAY_REG_ADDR	0x03
+#define RTC_DATE_REG_ADDR	0x04
+#define RTC_MON_REG_ADDR	0x05
+#define RTC_YR_REG_ADDR		0x06
+
+#define RTC_FLAG_REG_ADDR	0x0E
+#define RTC_FLAG_BIT_V1F	BIT(0)
+#define RTC_FLAG_BIT_V2F	BIT(1)
+
+#define RTC_CTL_REG_ADDR	0x0F
+#define RTC_CTL_BIT_RST		BIT(0)
+
+static int rv8803_rtc_set(struct udevice *dev, const struct rtc_time *tm)
+{
+	int ret;
+	u8 buf[7];
+
+	debug("Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
+	      tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_wday,
+	      tm->tm_hour, tm->tm_min, tm->tm_sec);
+
+	if (tm->tm_year < 2000 || tm->tm_year > 2099)
+		printf("WARNING: year should be between 2000 and 2099!\n");
+
+	buf[RTC_YR_REG_ADDR] = bin2bcd(tm->tm_year % 100);
+	buf[RTC_MON_REG_ADDR] = bin2bcd(tm->tm_mon);
+	buf[RTC_DAY_REG_ADDR] = 1 << (tm->tm_wday & 0x7);
+	buf[RTC_DATE_REG_ADDR] = bin2bcd(tm->tm_mday);
+	buf[RTC_HR_REG_ADDR] = bin2bcd(tm->tm_hour);
+	buf[RTC_MIN_REG_ADDR] = bin2bcd(tm->tm_min);
+	buf[RTC_SEC_REG_ADDR] = bin2bcd(tm->tm_sec);
+
+	ret = dm_i2c_write(dev, 0, buf, sizeof(buf));
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static int rv8803_rtc_get(struct udevice *dev, struct rtc_time *tm)
+{
+	int ret;
+	u8 buf[7];
+	int flags;
+
+	flags = dm_i2c_reg_read(dev, RTC_FLAG_REG_ADDR);
+	if (flags < 0)
+		return flags;
+	debug("%s: flags=%Xh\n", __func__, flags);
+
+	if (flags & RTC_FLAG_BIT_V1F)
+		printf("### Warning: temperature compensation has stopped\n");
+
+	if (flags & RTC_FLAG_BIT_V2F) {
+		printf("### Warning: Voltage low, data is invalid\n");
+		return -1;
+	}
+
+	ret = dm_i2c_read(dev, 0, buf, sizeof(buf));
+	if (ret < 0)
+		return ret;
+
+	tm->tm_sec  = bcd2bin(buf[RTC_SEC_REG_ADDR] & 0x7F);
+	tm->tm_min  = bcd2bin(buf[RTC_MIN_REG_ADDR] & 0x7F);
+	tm->tm_hour = bcd2bin(buf[RTC_HR_REG_ADDR] & 0x3F);
+	tm->tm_mday = bcd2bin(buf[RTC_DATE_REG_ADDR] & 0x3F);
+	tm->tm_mon  = bcd2bin(buf[RTC_MON_REG_ADDR] & 0x1F);
+	tm->tm_year = bcd2bin(buf[RTC_YR_REG_ADDR]) + 2000;
+	tm->tm_wday = fls(buf[RTC_DAY_REG_ADDR] & 0x7F) - 1;
+	tm->tm_yday = 0;
+	tm->tm_isdst = 0;
+
+	debug("Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
+	      tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_wday,
+	      tm->tm_hour, tm->tm_min, tm->tm_sec);
+
+	return 0;
+}
+
+static int rv8803_rtc_reset(struct udevice *dev)
+{
+	int ret;
+	struct rtc_time tmp = {
+		.tm_year = 2000,
+		.tm_mon = 1,
+		.tm_mday = 1,
+		.tm_hour = 0,
+		.tm_min = 0,
+		.tm_sec = 0,
+	};
+
+	/* assert reset */
+	ret = dm_i2c_reg_write(dev, RTC_CTL_REG_ADDR, RTC_CTL_BIT_RST);
+	if (ret < 0)
+		return ret;
+
+	/* clear all flags */
+	ret = dm_i2c_reg_write(dev, RTC_FLAG_REG_ADDR, 0);
+	if (ret < 0)
+		return ret;
+
+	ret = rv8803_rtc_set(dev, &tmp);
+	if (ret < 0)
+		return ret;
+
+	/* clear reset */
+	ret = dm_i2c_reg_write(dev, RTC_CTL_REG_ADDR, 0);
+	if (ret < 0)
+		return ret;
+
+	debug("RTC:   %4d-%02d-%02d %2d:%02d:%02d UTC\n",
+	      tmp.tm_year, tmp.tm_mon, tmp.tm_mday,
+	      tmp.tm_hour, tmp.tm_min, tmp.tm_sec);
+
+	return 0;
+}
+
+static int rv8803_probe(struct udevice *dev)
+{
+	i2c_set_chip_flags(dev, DM_I2C_CHIP_RD_ADDRESS |
+			   DM_I2C_CHIP_WR_ADDRESS);
+
+	return 0;
+}
+
+static const struct rtc_ops rv8803_rtc_ops = {
+	.get = rv8803_rtc_get,
+	.set = rv8803_rtc_set,
+	.reset = rv8803_rtc_reset,
+};
+
+static const struct udevice_id rv8803_rtc_ids[] = {
+	{ .compatible = "microcrystal,rv8803", },
+	{ }
+};
+
+U_BOOT_DRIVER(rtc_rv8803) = {
+	.name	= "rtc-rv8803",
+	.id	= UCLASS_RTC,
+	.probe	= rv8803_probe,
+	.of_match = rv8803_rtc_ids,
+	.ops	= &rv8803_rtc_ops,
+};