git: d22051b18e9b - main - iicbus/rtc: Add driver for the Ricoh rs5c372 RTC
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Date: Sun, 03 May 2026 19:11:56 UTC
The branch main has been updated by jhibbits:
URL: https://cgit.FreeBSD.org/src/commit/?id=d22051b18e9b7512c5cf033d7b6eee2df03c985b
commit d22051b18e9b7512c5cf033d7b6eee2df03c985b
Author: Justin Hibbits <jhibbits@FreeBSD.org>
AuthorDate: 2026-04-22 02:15:02 +0000
Commit: Justin Hibbits <jhibbits@FreeBSD.org>
CommitDate: 2026-05-03 19:09:28 +0000
iicbus/rtc: Add driver for the Ricoh rs5c372 RTC
This RTC chip supports 2 alarm timers in addition to RTC functionality,
but this driver only supports the RTC at this time.
---
sys/conf/files | 1 +
sys/dev/iicbus/rtc/rs5c372a.c | 182 ++++++++++++++++++++++++++++++++++++++
sys/modules/i2c/Makefile | 1 +
sys/modules/i2c/rs5c372a/Makefile | 14 +++
4 files changed, 198 insertions(+)
diff --git a/sys/conf/files b/sys/conf/files
index 2b4a453ca556..6804c9c81c69 100644
--- a/sys/conf/files
+++ b/sys/conf/files
@@ -1858,6 +1858,7 @@ dev/iicbus/rtc/hym8563.c optional hym8563 iicbus fdt
dev/iicbus/rtc/isl12xx.c optional isl12xx
dev/iicbus/rtc/nxprtc.c optional nxprtc | pcf8563
dev/iicbus/rtc/pcf85063.c optional pcf85063 iicbus fdt
+dev/iicbus/rtc/rs5c372a.c optional rs5c372a iicbus fdt
dev/iicbus/rtc/rtc8583.c optional rtc8583
dev/iicbus/rtc/rv3032.c optional rv3032 iicbus fdt
dev/iicbus/rtc/rx8803.c optional rx8803 iicbus fdt
diff --git a/sys/dev/iicbus/rtc/rs5c372a.c b/sys/dev/iicbus/rtc/rs5c372a.c
new file mode 100644
index 000000000000..c5743e840d25
--- /dev/null
+++ b/sys/dev/iicbus/rtc/rs5c372a.c
@@ -0,0 +1,182 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2026 Justin Hibbits
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/bus.h>
+#include <sys/clock.h>
+#include <sys/kernel.h>
+#include <sys/lock.h>
+#include <sys/module.h>
+
+#include <dev/ofw/ofw_bus.h>
+#include <dev/ofw/ofw_bus_subr.h>
+
+#include <dev/iicbus/iiconf.h>
+#include <dev/iicbus/iicbus.h>
+
+#include "clock_if.h"
+#include "iicbus_if.h"
+
+/*
+ * Driver for the Richo rs5c372a RTC. The chip itself includes 2 alarm clocks
+ * in addition to the clock component, but this driver offers only the RTC
+ * component.
+ *
+ * Like many other RTCs, this reports the date and time in BCD.
+ *
+ * The `Hour' register uses bit 5 in a dual role: In 24-hour time, it's a part
+ * of the first digit (0, 1, 2). In 12-hour time it denotes PM, so 12PM is
+ * reported as 0x32, 1PM is 0x21, etc.
+ */
+#define RS5C372_REG_SEC 0x0
+#define RS5C372_REG_MIN 0x1
+#define RS5C372_REG_HOUR 0x2
+#define HOUR_HR_M 0x1f
+#define HOUR_PM 0x20
+#define RS5C372_REG_DOW 0x3
+#define RS5C372_REG_DAY 0x4
+#define RS5C372_REG_MON 0x5
+#define RS5C372_REG_YEAR 0x6
+#define RS5C372_REG_CTRL1 0xe
+#define RS5C372_REG_CTRL2 0xf
+#define CTRL_PM 0x20
+
+static struct ofw_compat_data compat_data[] = {
+ { "ricoh,rs5c372a", 1 },
+ { NULL, 0 }
+};
+
+static int
+rs5c372a_gettime(device_t dev, struct timespec *ts)
+{
+ struct bcd_clocktime ct = {};
+ uint8_t clock_regs[7];
+ int err;
+ uint8_t ctrl2;
+ bool is_12hr = true;
+
+ err = iicdev_readfrom(dev, RS5C372_REG_CTRL2, &ctrl2,
+ sizeof(ctrl2), IIC_WAIT);
+ if (err != 0)
+ return (err);
+ err = iicdev_readfrom(dev, RS5C372_REG_SEC, clock_regs,
+ sizeof(clock_regs), IIC_WAIT);
+ if (err != 0)
+ return (err);
+
+ if (ctrl2 & CTRL_PM)
+ is_12hr = false;
+ ct.sec = clock_regs[RS5C372_REG_SEC];
+ ct.min = clock_regs[RS5C372_REG_MIN];
+ ct.hour = clock_regs[RS5C372_REG_HOUR];
+ ct.dow = clock_regs[RS5C372_REG_DOW];
+ ct.day = clock_regs[RS5C372_REG_DAY];
+ ct.mon = clock_regs[RS5C372_REG_MON];
+ ct.year = clock_regs[RS5C372_REG_YEAR];
+
+ if (is_12hr) {
+ ct.ispm = ct.hour & HOUR_PM;
+ ct.hour &= HOUR_HR_M;
+ }
+ clock_bcd_to_ts(&ct, ts, ct.ispm);
+
+ return (0);
+}
+
+static int
+rs5c372a_settime(device_t dev, struct timespec *ts)
+{
+ struct bcd_clocktime ct;
+ uint8_t clock_regs[7];
+ uint8_t ctrl2;
+ int err;
+ bool is_12hr = true;
+
+ err = iicdev_readfrom(dev, RS5C372_REG_CTRL2, &ctrl2,
+ sizeof(ctrl2), IIC_WAIT);
+ if (err != 0)
+ return (err);
+ if (ctrl2 & CTRL_PM)
+ is_12hr = false;
+ clock_ts_to_bcd(ts, &ct, is_12hr);
+ clock_regs[RS5C372_REG_SEC] = ct.sec;
+ clock_regs[RS5C372_REG_MIN] = ct.min;
+ clock_regs[RS5C372_REG_HOUR] = ct.hour;
+ clock_regs[RS5C372_REG_DAY] = ct.day;
+ clock_regs[RS5C372_REG_DOW] = ct.dow;
+ clock_regs[RS5C372_REG_MON] = ct.mon;
+ clock_regs[RS5C372_REG_YEAR] = ct.year & 0xff;
+
+ if (is_12hr) {
+ if (ct.ispm)
+ clock_regs[RS5C372_REG_HOUR] |= HOUR_PM;
+ }
+
+ err = iicdev_writeto(dev, RS5C372_REG_SEC, clock_regs,
+ sizeof(clock_regs), IIC_WAIT);
+
+ return (err);
+}
+
+static int
+rs5c372a_probe(device_t dev)
+{
+ if (ofw_bus_search_compatible(dev, compat_data)->ocd_data == 0)
+ return (ENXIO);
+
+ device_set_desc(dev, "Richo RS5C372A RTC");
+
+ return (BUS_PROBE_DEFAULT);
+}
+
+static int
+rs5c372a_attach(device_t dev)
+{
+
+ /* Register with 1s resolution */
+ clock_register(dev, 1000000);
+ clock_schedule(dev, 1);
+ return (0);
+}
+
+static device_method_t rs5c372a_methods[] = {
+ /* Device methods */
+ DEVMETHOD(device_probe, rs5c372a_probe),
+ DEVMETHOD(device_attach, rs5c372a_attach),
+
+ /* Clock methods */
+ DEVMETHOD(clock_gettime, rs5c372a_gettime),
+ DEVMETHOD(clock_settime, rs5c372a_settime),
+ DEVMETHOD_END
+};
+
+
+DEFINE_CLASS_0(rs5c372a, rs5c372a_driver, rs5c372a_methods, 0);
+DRIVER_MODULE(rs5c372a, iicbus, rs5c372a_driver, NULL, NULL);
+MODULE_VERSION(rs5c372a, 1);
+MODULE_DEPEND(rs5c372a, iicbus, IICBUS_MINVER, IICBUS_PREFVER, IICBUS_MAXVER);
+IICBUS_FDT_PNP_INFO(compat_data);
diff --git a/sys/modules/i2c/Makefile b/sys/modules/i2c/Makefile
index 6561327abfca..ff4536694dfc 100644
--- a/sys/modules/i2c/Makefile
+++ b/sys/modules/i2c/Makefile
@@ -28,6 +28,7 @@ SUBDIR = \
.if !empty(OPT_FDT)
SUBDIR += hym8563 \
+ rs5c372a \
rv3032 \
rx8803 \
tca64xx \
diff --git a/sys/modules/i2c/rs5c372a/Makefile b/sys/modules/i2c/rs5c372a/Makefile
new file mode 100644
index 000000000000..3bd387115a8a
--- /dev/null
+++ b/sys/modules/i2c/rs5c372a/Makefile
@@ -0,0 +1,14 @@
+.PATH: ${SRCTOP}/sys/dev/iicbus/rtc/
+KMOD = rs5c372a
+SRCS = rs5c372a.c
+
+# Generated files...
+SRCS+= \
+ bus_if.h \
+ clock_if.h \
+ device_if.h \
+ iicbus_if.h \
+ opt_platform.h \
+ ofw_bus_if.h \
+
+.include <bsd.kmod.mk>