[PATCH v2 0/3] rtc: rs5c372: add Ricoh R2223x support

[PATCH v2 0/3] rtc: rs5c372: add Ricoh R2223x support

[Heiko Schocher]

The Ricoh R2223x is an I2C RTC from the same family as the r2025sd and
r2221tl which the rtc-rs5c372 already supports. It shares the R2x2x
control register layout, so only the new type must be added to the driver.

The ricoh R2223x drives a clock output and offers an eco mode that
lowers its current consumption while running from the backup supply.

The trivial-rtc binding does not cover this, so give the device its
own binding in patch 1. Patch 2 adds the R2223x to the rs5c372 rtc
driver, and patch 3 implements the eco-mode setting.

v2 answers the sashiko review of v1 and a local run of the same review
prompts. This resulted in 2 changes:

Patch 2 now handles the new type in rs5c372_ioctl(), where RTC_VL_READ
read CTRL2 bit 4 as XSTP although the R2x2x parts have PON there and
RTC_VL_CLR did nothing at all, and in the two offset helpers, where the
R2223x fell back to the coarse trim resolution.

Patch 3 now applies the device tree setting in both directions. V1 only
set the eco bit before, so a board that dropped the property kept running
in eco mode, because CTRL2 is backed by the backup supply.

Not touched sashiko reviews (some from local run):

- #clock-cells stays out of the required list. Requiring it would
  reject every node that does not use the clock output; the other
  discrete I2C RTC bindings with a clock output keep it optional too.
  Also the clock output can be disabled per hardware pin CLKC. So
  #clock-cells is optional.

  https://sashiko.dev/#/patchset/20260824110452.4038870-1-hs@nabladev.com?part=1

- additionalProperties: false together with $ref: rtc.yaml# means the
  properties from rtc.yaml are not allowed here unless they are listed.
  Only start-year is, the others can be added once a board needs them.
  microcrystal,rv3032.yaml is built the same way.

- ricoh,eco-mode is a vendor boolean. Whether the RTC may run in eco
  mode depends on the backup cell the board is fitted with, so it
  describes the board and not a runtime policy.

Changes in v2:
- Added Reviewed-by from Conor, no code change in patch 1
- Fixed the sashiko review of v1: handle the new type in
  rs5c372_ioctl(), rs5c372_read_offset() and rs5c372_set_offset()
  https://sashiko.dev/#/patchset/20260824110452.4038870-1-hs@nabladev.com?part=2
- Added sashiko review for patch 3 in this patch, as it fits better here
  https://sashiko.dev/#/patchset/20260824110452.4038870-1-hs@nabladev.com?part=3
- Fixed results of a local run of the sashiko review prompts: apply the
  device tree setting in both directions. v1 only set the eco bit, so
  the mode stayed on when a board dropped the property.
- Leave rs5c372_probe() through goto exit like its other error paths,
  instead of returning directly.

Heiko Schocher (3):
  dt-bindings: rtc: add ricoh,r2223x binding
  rtc: rs5c372: add support for Ricoh R2223x
  rtc: rs5c372: support eco mode on R2223x

 .../devicetree/bindings/rtc/ricoh,r2223x.yaml | 58 +++++++++++++++++++
 drivers/rtc/rtc-rs5c372.c                     | 52 ++++++++++++++++-
 2 files changed, 107 insertions(+), 3 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/rtc/ricoh,r2223x.yaml

---
base-commit: 2709dd5ae32f0828f386327c76bba9f39f63a1c6

-- 
2.55.0

[PATCH v2 1/3] dt-bindings: rtc: add ricoh,r2223x binding

[Heiko Schocher]

The Ricoh R2223x is an I2C RTC of the same family as the r2025sd and
r2221tl which the rtc-rs5c372 already supports. It drives a clock output
and can be put into an eco mode that lowers its current consumption from
the backup supply, so it needs #clock-cells and a property for the eco
mode.

The trivial-rtc binding does not cover this, so give the device its
own binding.

Signed-off-by: Heiko Schocher <hs@nabladev.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
---

Changes in v2:
- Added Reviewed-by from Conor, no code change in patch 1

 .../devicetree/bindings/rtc/ricoh,r2223x.yaml | 58 +++++++++++++++++++
 1 file changed, 58 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/rtc/ricoh,r2223x.yaml

diff --git a/Documentation/devicetree/bindings/rtc/ricoh,r2223x.yaml b/Documentation/devicetree/bindings/rtc/ricoh,r2223x.yaml
new file mode 100644
index 000000000000..e64a1ee378e6
--- /dev/null
+++ b/Documentation/devicetree/bindings/rtc/ricoh,r2223x.yaml
@@ -0,0 +1,58 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/rtc/ricoh,r2223x.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Ricoh R2223x Real-Time Clock
+
+maintainers:
+  - Heiko Schocher <hs@nabladev.com>
+
+allOf:
+  - $ref: rtc.yaml#
+
+properties:
+  compatible:
+    const: ricoh,r2223x
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  "#clock-cells":
+    const: 0
+
+  ricoh,eco-mode:
+    type: boolean
+    description:
+      Put the RTC into eco mode, which lowers its current consumption while
+      running from the backup supply. Set this on boards where the RTC is
+      expected to keep time on a small backup cell.
+
+  start-year: true
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        rtc@32 {
+            compatible = "ricoh,r2223x";
+            reg = <0x32>;
+            interrupts = <6 IRQ_TYPE_EDGE_FALLING>;
+            #clock-cells = <0>;
+            ricoh,eco-mode;
+        };
+    };
-- 
2.55.0

[PATCH v2 2/3] rtc: rs5c372: add support for Ricoh R2223x

[Heiko Schocher]

The R2223x is an I2C RTC from the same family as the r2025sd and r2221tl
that this driver already handles. It shares the R2x2x control register
layout, so treat it like the r2221tl. The oscillator interrupt flag is
reported through XSTP, and the 24 hour mode bit lives in CTRL1. It also
has the DEV bit in the trim register, so same as r2221tl.

Signed-off-by: Heiko Schocher <hs@nabladev.com>
Reported-by: Sashiko AI review <sashiko-bot@kernel.org>
Closes: https://sashiko.dev/#/patchset/20260824110452.4038870-1-hs@nabladev.com?part=2
Closes: https://sashiko.dev/#/patchset/20260824110452.4038870-1-hs@nabladev.com?part=3
---
checkpatch reports on this patch

  ERROR: trailing statements should be on next line
  +                     case rtc_r2223x:        s = "r2223x"; break;

I did not fix this checkpatch error, as the whole switch statement uses
this format.

Changes in v2:
- Fixed the sashiko review of v1: handle the new type in
  rs5c372_ioctl(), rs5c372_read_offset() and rs5c372_set_offset()
  https://sashiko.dev/#/patchset/20260824110452.4038870-1-hs@nabladev.com?part=2
- Added sashiko review for patch 3 in this patch, as it fits better here
  https://sashiko.dev/#/patchset/20260824110452.4038870-1-hs@nabladev.com?part=3

 drivers/rtc/rtc-rs5c372.c | 24 +++++++++++++++++++++---
 1 file changed, 21 insertions(+), 3 deletions(-)

diff --git a/drivers/rtc/rtc-rs5c372.c b/drivers/rtc/rtc-rs5c372.c
index 24bd795d9d95..c65b76cc0dc6 100644
--- a/drivers/rtc/rtc-rs5c372.c
+++ b/drivers/rtc/rtc-rs5c372.c
@@ -68,6 +68,7 @@ enum rtc_type {
 	rtc_undef = 0,
 	rtc_r2025sd,
 	rtc_r2221tl,
+	rtc_r2223x,
 	rtc_rs5c372a,
 	rtc_rs5c372b,
 	rtc_rv5c386,
@@ -77,6 +78,7 @@ enum rtc_type {
 static const struct i2c_device_id rs5c372_id[] = {
 	{ .name = "r2025sd", .driver_data = rtc_r2025sd },
 	{ .name = "r2221tl", .driver_data = rtc_r2221tl },
+	{ .name = "r2223x", .driver_data = rtc_r2223x },
 	{ .name = "rs5c372a", .driver_data = rtc_rs5c372a },
 	{ .name = "rs5c372b", .driver_data = rtc_rs5c372b },
 	{ .name = "rv5c386", .driver_data = rtc_rv5c386 },
@@ -94,6 +96,10 @@ static const __maybe_unused struct of_device_id rs5c372_of_match[] = {
 		.compatible = "ricoh,r2221tl",
 		.data = (void *)rtc_r2221tl
 	},
+	{
+		.compatible = "ricoh,r2223x",
+		.data = (void *)rtc_r2223x
+	},
 	{
 		.compatible = "ricoh,rs5c372a",
 		.data = (void *)rtc_rs5c372a
@@ -221,8 +227,10 @@ static int rs5c372_rtc_read_time(struct device *dev, struct rtc_time *tm)
 	switch (rs5c->type) {
 	case rtc_r2025sd:
 	case rtc_r2221tl:
+	case rtc_r2223x:
 		if ((rs5c->type == rtc_r2025sd && !(ctrl2 & R2x2x_CTRL2_XSTP)) ||
-		    (rs5c->type == rtc_r2221tl &&  (ctrl2 & R2x2x_CTRL2_XSTP))) {
+		    ((rs5c->type == rtc_r2221tl || rs5c->type == rtc_r2223x) &&
+		     (ctrl2 & R2x2x_CTRL2_XSTP))) {
 			dev_warn(&client->dev, "rtc oscillator interruption detected. Please reset the rtc clock.\n");
 			return -EINVAL;
 		}
@@ -292,6 +300,7 @@ static int rs5c372_rtc_set_time(struct device *dev, struct rtc_time *tm)
 	switch (rs5c->type) {
 	case rtc_r2025sd:
 	case rtc_r2221tl:
+	case rtc_r2223x:
 		ctrl2 &= ~(R2x2x_CTRL2_VDET | R2x2x_CTRL2_PON);
 		if (rs5c->type == rtc_r2025sd)
 			ctrl2 |= R2x2x_CTRL2_XSTP;
@@ -511,8 +520,10 @@ static int rs5c372_ioctl(struct device *dev, unsigned int cmd, unsigned long arg
 		switch (rs5c->type) {
 		case rtc_r2025sd:
 		case rtc_r2221tl:
+		case rtc_r2223x:
 			if ((rs5c->type == rtc_r2025sd && !(ctrl2 & R2x2x_CTRL2_XSTP)) ||
-				(rs5c->type == rtc_r2221tl &&  (ctrl2 & R2x2x_CTRL2_XSTP))) {
+			    ((rs5c->type == rtc_r2221tl || rs5c->type == rtc_r2223x) &&
+			     (ctrl2 & R2x2x_CTRL2_XSTP))) {
 				flags |= RTC_VL_DATA_INVALID;
 			}
 			if (ctrl2 & R2x2x_CTRL2_VDET)
@@ -527,7 +538,8 @@ static int rs5c372_ioctl(struct device *dev, unsigned int cmd, unsigned long arg
 		return put_user(flags, (unsigned int __user *)arg);
 	case RTC_VL_CLR:
 		/* clear VDET bit */
-		if (rs5c->type == rtc_r2025sd || rs5c->type == rtc_r2221tl) {
+		if (rs5c->type == rtc_r2025sd || rs5c->type == rtc_r2221tl ||
+		    rs5c->type == rtc_r2223x) {
 			ctrl2 &= ~R2x2x_CTRL2_VDET;
 			if (i2c_smbus_write_byte_data(rs5c->client, addr, ctrl2) < 0) {
 				dev_dbg(&rs5c->client->dev, "%s: write error in line %i\n",
@@ -554,6 +566,7 @@ static int rs5c372_read_offset(struct device *dev, long *offset)
 
 	switch (rs5c->type) {
 	case rtc_r2221tl:
+	case rtc_r2223x:
 		ppb_per_step = val & R2221TL_TRIM_DEV ? 1017 : 3051;
 		break;
 	case rtc_rs5c372a:
@@ -600,6 +613,7 @@ static int rs5c372_set_offset(struct device *dev, long offset)
 		}
 		break;
 	case rtc_r2221tl:
+	case rtc_r2223x:
 		/*
 		 * Check if it is possible to use high resolution mode (DEV=1).
 		 * In this mode, the minimum resolution is 2 / (32768 * 20 * 3),
@@ -750,6 +764,7 @@ static int rs5c_oscillator_setup(struct rs5c372 *rs5c372)
 			return ret;
 		break;
 	case rtc_r2221tl:
+	case rtc_r2223x:
 		if (!(buf[1] & R2x2x_CTRL2_XSTP))
 			return ret;
 		break;
@@ -768,6 +783,7 @@ static int rs5c_oscillator_setup(struct rs5c372 *rs5c372)
 		break;
 	case rtc_r2025sd:
 	case rtc_r2221tl:
+	case rtc_r2223x:
 	case rtc_rv5c386:
 	case rtc_rv5c387a:
 		buf[0] |= RV5C387_CTRL1_24;
@@ -847,6 +863,7 @@ static int rs5c372_probe(struct i2c_client *client)
 		break;
 	case rtc_r2025sd:
 	case rtc_r2221tl:
+	case rtc_r2223x:
 	case rtc_rv5c386:
 	case rtc_rv5c387a:
 		if (rs5c372->regs[RS5C_REG_CTRL1] & RV5C387_CTRL1_24)
@@ -876,6 +893,7 @@ static int rs5c372_probe(struct i2c_client *client)
 			({ char *s; switch (rs5c372->type) {
 			case rtc_r2025sd:	s = "r2025sd"; break;
 			case rtc_r2221tl:	s = "r2221tl"; break;
+			case rtc_r2223x:	s = "r2223x"; break;
 			case rtc_rs5c372a:	s = "rs5c372a"; break;
 			case rtc_rs5c372b:	s = "rs5c372b"; break;
 			case rtc_rv5c386:	s = "rv5c386"; break;
-- 
2.55.0

[PATCH v2 3/3] rtc: rs5c372: support eco mode on R2223x

[Heiko Schocher]

The R2223x can run in an eco mode that lowers its current consumption
from the backup supply. Follow the ricoh,eco-mode property from the
device tree: enable the mode when the property is set, turn it off when
it is not set, as the bit is in CTRL2 register, which is backed by the
same supply and keeps its contents across a reset, and no other path in
the driver touches it.

Signed-off-by: Heiko Schocher <hs@nabladev.com>
---

Changes in v2:
- Fixed results of a local run of the sashiko review prompts: apply the
  device tree setting in both directions. v1 only set the eco bit, so
  the mode stayed on when a board dropped the property.
- Leave rs5c372_probe() through goto exit like its other error paths,
  instead of returning directly.

 drivers/rtc/rtc-rs5c372.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/drivers/rtc/rtc-rs5c372.c b/drivers/rtc/rtc-rs5c372.c
index c65b76cc0dc6..9ab6f2c28f7b 100644
--- a/drivers/rtc/rtc-rs5c372.c
+++ b/drivers/rtc/rtc-rs5c372.c
@@ -52,6 +52,7 @@
 #define RS5C_REG_CTRL2		15
 #	define RS5C372_CTRL2_24		(1 << 5)
 #	define RS5C_CTRL2_XSTP		(1 << 4)	/* only if !R2x2x */
+#	define R2223x_CTRL2_ECO		(1 << 7)	/* only if  R2223x */
 #	define R2x2x_CTRL2_VDET		(1 << 6)	/* only if  R2x2x */
 #	define R2x2x_CTRL2_XSTP		(1 << 5)	/* only if  R2x2x */
 #	define R2x2x_CTRL2_PON		(1 << 4)	/* only if  R2x2x */
@@ -807,6 +808,24 @@ static int rs5c_oscillator_setup(struct rs5c372 *rs5c372)
 	return 0;
 }
 
+static int rs5c372_set_eco_mode(struct rs5c372 *rs5c372, bool eco)
+{
+	struct i2c_client *client = rs5c372->client;
+	int ctrl2;
+
+	ctrl2 = i2c_smbus_read_byte_data(client, RS5C_ADDR(RS5C_REG_CTRL2));
+	if (ctrl2 < 0)
+		return ctrl2;
+
+	if (eco)
+		ctrl2 |= R2223x_CTRL2_ECO;
+	else
+		ctrl2 &= ~R2223x_CTRL2_ECO;
+
+	return i2c_smbus_write_byte_data(client, RS5C_ADDR(RS5C_REG_CTRL2),
+					 ctrl2);
+}
+
 static int rs5c372_probe(struct i2c_client *client)
 {
 	int err = 0;
@@ -903,6 +922,15 @@ static int rs5c372_probe(struct i2c_client *client)
 			rs5c372->time24 ? "24hr" : "am/pm"
 			);
 
+	if (rs5c372->type == rtc_r2223x) {
+		bool eco = device_property_read_bool(&client->dev,
+						     "ricoh,eco-mode");
+
+		err = rs5c372_set_eco_mode(rs5c372, eco);
+		if (err < 0)
+			goto exit;
+	}
+
 	/* REVISIT use client->irq to register alarm irq ... */
 	rs5c372->rtc = devm_rtc_device_register(&client->dev,
 					rs5c372_driver.driver.name,
-- 
2.55.0