[PATCH v1 0/3] rtc: rs5c372: add Ricoh R2223x support

[PATCH v1 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 enable setting.



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                     | 41 ++++++++++++-
 2 files changed, 98 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/devicetree/bindings/rtc/ricoh,r2223x.yaml

---
base-commit: 2709dd5ae32f0828f386327c76bba9f39f63a1c6

-- 
2.55.0

[PATCH v1 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>
---

 .../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

Re: [PATCH v1 1/3] dt-bindings: rtc: add ricoh,r2223x binding

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] The `#clock-cells` property is missing from the `required` list for a device that acts as a clock provider.
--

--- Patch [1]: [PATCH v1 1/3] dt-bindings: rtc: add ricoh,r2223x binding ---
commit 650ba92edebadde8c761f1e4168721297f6edde4
Author: Heiko Schocher <hs@nabladev.com>

dt-bindings: rtc: add ricoh,r2223x binding

This commit introduces a new device tree binding for the Ricoh R2223x
Real-Time Clock. It adds schema definitions for its compatible string,
clock provider capabilities, and an eco mode property.

> diff --git a/Documentation/devicetree/bindings/rtc/ricoh,r2223x.yaml b/Documentation/devicetree/bindings/rtc/ricoh,r2223x.yaml
> new file mode 100644
> index 0000000000000..e64a1ee378e64
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/rtc/ricoh,r2223x.yaml
[ ... ]
> +  start-year: true
> +
> +required:
> +  - compatible
> +  - reg

[Severity: Medium]
Since this device acts as a clock provider and defines #clock-cells above,
should #clock-cells be explicitly included in this required list?

Without it, device tree nodes that omit the property could silently pass
schema validation, potentially leading to runtime failures in dependent
drivers attempting to use the clock functionality.

> +
> +additionalProperties: false

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

Re: [PATCH v1 1/3] dt-bindings: rtc: add ricoh,r2223x binding

[Conor Dooley]

[-- Attachment #1: Type: text/plain, Size: 600 bytes --]

On Mon, Aug 24, 2026 at 01:04:24PM +0200, Heiko Schocher wrote:
> 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>
pw-bot: not-applicable

[-- Attachment #2: signature.asc --]
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[PATCH v1 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.

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

 drivers/rtc/rtc-rs5c372.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/rtc/rtc-rs5c372.c b/drivers/rtc/rtc-rs5c372.c
index 24bd795d9d95..30e272d65021 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;
@@ -750,6 +759,7 @@ 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 +778,7 @@ 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 +858,7 @@ 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 +888,7 @@ 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

Re: [PATCH v1 2/3] rtc: rs5c372: add support for Ricoh R2223x

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] The new RTC type `rtc_r2223x` is missing from the switch statements in `rs5c372_ioctl()`, `rs5c372_read_offset()`, and `rs5c372_set_offset()`.
--

--- Patch [2]: [PATCH v1 2/3] rtc: rs5c372: add support for Ricoh R2223x ---
commit f8cda87e08814c0d84a3917bdc200d86363e7127
Author: Heiko Schocher <hs@nabladev.com>

rtc: rs5c372: add support for Ricoh R2223x
    
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.

> diff --git a/drivers/rtc/rtc-rs5c372.c b/drivers/rtc/rtc-rs5c372.c
> index 24bd795d9d95d..30e272d650219 100644
> --- a/drivers/rtc/rtc-rs5c372.c
> +++ b/drivers/rtc/rtc-rs5c372.c
[ ... ]
> @@ -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))) {

[Severity: Medium]
Since rtc_r2223x shares the register layout with rtc_r2221tl, should it also be
added to the switch statements in rs5c372_ioctl(), rs5c372_read_offset(), and
rs5c372_set_offset()?

Without it, RTC_VL_READ falls into the default path, ignoring VDET and
returning incorrect XSTP bits. RTC_VL_CLR also fails to clear the VDET hardware
flag:

	case RTC_VL_CLR:
		/* clear VDET bit */
		if (rs5c->type == rtc_r2025sd || rs5c->type == rtc_r2221tl) {
			ctrl2 &= ~R2x2x_CTRL2_VDET;
			...

Additionally, rs5c372_read_offset() and rs5c372_set_offset() will skip using
the higher resolution DEV mode for rtc_r2223x, falling back to the default low
resolution calculations:

	switch (rs5c->type) {
	case rtc_r2221tl:
		ppb_per_step = val & R2221TL_TRIM_DEV ? 1017 : 3051;
		break;
	...

>  			dev_warn(&client->dev, "rtc oscillator interruption detected. Please reset the rtc clock.\n");
>  			return -EINVAL;
>  		}

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260824110452.4038870-1-hs@nabladev.com?part=2

[PATCH v1 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. Enable it when ricoh,eco-mode property is
set in the device tree.

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

 drivers/rtc/rtc-rs5c372.c | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/drivers/rtc/rtc-rs5c372.c b/drivers/rtc/rtc-rs5c372.c
index 30e272d65021..41d391bf07f7 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 */
@@ -802,6 +803,24 @@ 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;
@@ -898,6 +917,13 @@ static int rs5c372_probe(struct i2c_client *client)
 			rs5c372->time24 ? "24hr" : "am/pm"
 			);
 
+	if (rs5c372->type == rtc_r2223x &&
+	    device_property_read_bool(&client->dev, "ricoh,eco-mode")) {
+		err = rs5c372_set_eco_mode(rs5c372, true);
+		if (err < 0)
+			return err;
+	}
+
 	/* REVISIT use client->irq to register alarm irq ... */
 	rs5c372->rtc = devm_rtc_device_register(&client->dev,
 					rs5c372_driver.driver.name,
-- 
2.55.0

Re: [PATCH v1 3/3] rtc: rs5c372: support eco mode on R2223x

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] The `rtc_r2223x` device is unhandled in the `RTC_VL_READ` and `RTC_VL_CLR` ioctls, causing incorrect voltage reporting and an inability to clear voltage warnings.
--

--- Patch [3]: [PATCH v1 3/3] rtc: rs5c372: support eco mode on R2223x ---
commit 03356cfada315a3baf4a319faaa5eba9b7ccba15
Author: Heiko Schocher <hs@nabladev.com>

rtc: rs5c372: support eco mode on R2223x
    
The R2223x can run in an eco mode that lowers its current consumption
from the backup supply. Enable it when ricoh,eco-mode property is
set in the device tree.

> diff --git a/drivers/rtc/rtc-rs5c372.c b/drivers/rtc/rtc-rs5c372.c
> index 30e272d650219..41d391bf07f7c 100644
> --- a/drivers/rtc/rtc-rs5c372.c
> +++ b/drivers/rtc/rtc-rs5c372.c

[ ... ]

> @@ -898,6 +917,13 @@ static int rs5c372_probe(struct i2c_client *client)
>  			rs5c372->time24 ? "24hr" : "am/pm"
>  			);
>  
> +	if (rs5c372->type == rtc_r2223x &&
> +	    device_property_read_bool(&client->dev, "ricoh,eco-mode")) {
> +		err = rs5c372_set_eco_mode(rs5c372, true);
> +		if (err < 0)
> +			return err;
> +	}
> +

[Severity: Medium]
Are we missing rtc_r2223x support in rs5c372_ioctl() for RTC_VL_READ and
RTC_VL_CLR?

For RTC_VL_READ, without rtc_r2223x in the switch statement, it falls through
to the default handler which misinterprets the PON bit (bit 4) as the
oscillator stopped (XSTP) bit, and ignores the voltage low (VDET) bit:

drivers/rtc/rtc-rs5c372.c:rs5c372_ioctl() {
    ...
		switch (rs5c->type) {
		case rtc_r2025sd:
		case rtc_r2221tl:
			// ... checks R2x2x_CTRL2_XSTP and R2x2x_CTRL2_VDET ...
			break;
		default:
			if (ctrl2 & RS5C_CTRL2_XSTP)
				flags |= RTC_VL_DATA_INVALID;
			break;
		}
    ...
}

Similarly, for RTC_VL_CLR, userspace cannot clear the voltage warning bit
because rtc_r2223x is omitted from the check:

drivers/rtc/rtc-rs5c372.c:rs5c372_ioctl() {
    ...
	case RTC_VL_CLR:
		/* clear VDET bit */
		if (rs5c->type == rtc_r2025sd || rs5c->type == rtc_r2221tl) {
			ctrl2 &= ~R2x2x_CTRL2_VDET;
    ...
}

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260824110452.4038870-1-hs@nabladev.com?part=3