[PATCH v3 0/3] On-chip RTC support for ExynosAutov9

[PATCH v3 0/3] On-chip RTC support for ExynosAutov9

[Devang Tailor]

Enable on-chip RTC support. The on-chip RTC of this SoC is similar
to the previous version of Samsung SoCs except for TICNT tick time
counter. So re-use the existing RTC driver with applicable call-backs
for initialization and IRQ handling without accessing TICNT counter.

As suggested in review comment, instead of adding separate disable()
call-back, re-used the existing s3c24xx_rtc_disable() by adding a new
bool 'use_s3c2410_ticnt' in rtc_data to avoid accessing TICNT counter
which is not valid for RTC of ExynosAutov9.

Setting and getting hardware clock has been tested using 'hwclock'
and 'date' utilities.

Alarm interrupt has been checked with incrementing interrupt
count via "cat /proc/interrupts | grep rtc" for 10sec
wakeup time via "echo +10 > /sys/class/rtc/rtc0/wakealarm"

changelog
---
Changes in v3:
- 1/3 : Added Tag 'Reviewed-by'
- 2/3 : Fixed the review comment of v2 to re-use the existing disable()
	instead of adding new one.
      : Not adding Tag 'Reviewed-by' from V2 since the patch has been
	changed
- 3/3 : Added Tag 'Reviewed-by'
link for v2 : https://lore.kernel.org/linux-rtc/20250710083434.1821671-1-dev.tailor@samsung.com/


Changes in v2:
- Fixed the review comment of v1 for mis-aligmnent & asymmetry bit logic.
- link for v1 : https://lore.kernel.org/linux-rtc/20250702052426.2404256-1-dev.tailor@samsung.com/


Devang Tailor (3):
  dt-bindings: rtc: s3c-rtc: add compatible for exynosautov9
  rtc: s3c: support for exynosautov9 on-chip RTC
  arm64: dts: exynosautov9: add RTC DT node

 .../devicetree/bindings/rtc/s3c-rtc.yaml      |  1 +
 .../boot/dts/exynos/exynosautov9-sadk.dts     |  4 ++++
 arch/arm64/boot/dts/exynos/exynosautov9.dtsi  | 10 +++++++++
 drivers/rtc/rtc-s3c.c                         | 21 ++++++++++++++++---
 4 files changed, 33 insertions(+), 3 deletions(-)


base-commit: 4ac65880ebca1b68495bd8704263b26c050ac010
-- 
2.34.1

[PATCH v3 1/3] dt-bindings: rtc: s3c-rtc: add compatible for exynosautov9

[Devang Tailor]

Add "samsung,exynosautov9-rtc" dedicated compatible for
on-chip RTC found in ExynosAutov9 SoC.

Signed-off-by: Devang Tailor <dev.tailor@samsung.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
---
 Documentation/devicetree/bindings/rtc/s3c-rtc.yaml | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Documentation/devicetree/bindings/rtc/s3c-rtc.yaml b/Documentation/devicetree/bindings/rtc/s3c-rtc.yaml
index bf4e11d6dffb..5daee2a5f866 100644
--- a/Documentation/devicetree/bindings/rtc/s3c-rtc.yaml
+++ b/Documentation/devicetree/bindings/rtc/s3c-rtc.yaml
@@ -13,6 +13,7 @@ properties:
   compatible:
     oneOf:
       - enum:
+          - samsung,exynosautov9-rtc
           - samsung,s3c2410-rtc
           - samsung,s3c2416-rtc
           - samsung,s3c2443-rtc
-- 
2.34.1

[PATCH v3 2/3] rtc: s3c: support for exynosautov9 on-chip RTC

[Devang Tailor]

The on-chip RTC of this SoC is almost similar to the previous version of
SoCs except for S3C2410_TICNT tick time counter, which is used in this
driver but not applicable for exynosautov9. So re-use the existing driver
skipping disablement of S3C2410_TICNT in s3c24xx_rtc_disable() callback
via a new boolean member of s3c_rtc_data.

This has been tested with 'hwclock' & 'date' utilities

Suggested-by: Henrik Grimler <henrik@grimler.se>
Signed-off-by: Devang Tailor <dev.tailor@samsung.com>
---
 drivers/rtc/rtc-s3c.c | 21 ++++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

diff --git a/drivers/rtc/rtc-s3c.c b/drivers/rtc/rtc-s3c.c
index 79b2a16f15ad..8fc5b4582b6d 100644
--- a/drivers/rtc/rtc-s3c.c
+++ b/drivers/rtc/rtc-s3c.c
@@ -48,6 +48,7 @@ struct s3c_rtc {
 
 struct s3c_rtc_data {
 	bool needs_src_clk;
+	bool use_s3c2410_ticnt;
 
 	void (*irq_handler) (struct s3c_rtc *info, int mask);
 	void (*enable) (struct s3c_rtc *info);
@@ -369,9 +370,11 @@ static void s3c24xx_rtc_disable(struct s3c_rtc *info)
 	con &= ~S3C2410_RTCCON_RTCEN;
 	writew(con, info->base + S3C2410_RTCCON);
 
-	con = readb(info->base + S3C2410_TICNT);
-	con &= ~S3C2410_TICNT_ENABLE;
-	writeb(con, info->base + S3C2410_TICNT);
+	if (info->data->use_s3c2410_ticnt) {
+		con = readb(info->base + S3C2410_TICNT);
+		con &= ~S3C2410_TICNT_ENABLE;
+		writeb(con, info->base + S3C2410_TICNT);
+	}
 }
 
 static void s3c6410_rtc_disable(struct s3c_rtc *info)
@@ -550,18 +553,21 @@ static void s3c6410_rtc_irq(struct s3c_rtc *info, int mask)
 }
 
 static const struct s3c_rtc_data s3c2410_rtc_data = {
+	.use_s3c2410_ticnt	= true,
 	.irq_handler		= s3c24xx_rtc_irq,
 	.enable			= s3c24xx_rtc_enable,
 	.disable		= s3c24xx_rtc_disable,
 };
 
 static const struct s3c_rtc_data s3c2416_rtc_data = {
+	.use_s3c2410_ticnt	= true,
 	.irq_handler		= s3c24xx_rtc_irq,
 	.enable			= s3c24xx_rtc_enable,
 	.disable		= s3c24xx_rtc_disable,
 };
 
 static const struct s3c_rtc_data s3c2443_rtc_data = {
+	.use_s3c2410_ticnt	= true,
 	.irq_handler		= s3c24xx_rtc_irq,
 	.enable			= s3c24xx_rtc_enable,
 	.disable		= s3c24xx_rtc_disable,
@@ -574,6 +580,12 @@ static const struct s3c_rtc_data s3c6410_rtc_data = {
 	.disable		= s3c6410_rtc_disable,
 };
 
+static const struct s3c_rtc_data exynosautov9_rtc_data = {
+	.irq_handler		= s3c6410_rtc_irq,
+	.enable			= s3c24xx_rtc_enable,
+	.disable		= s3c24xx_rtc_disable,
+};
+
 static const __maybe_unused struct of_device_id s3c_rtc_dt_match[] = {
 	{
 		.compatible = "samsung,s3c2410-rtc",
@@ -590,6 +602,9 @@ static const __maybe_unused struct of_device_id s3c_rtc_dt_match[] = {
 	}, {
 		.compatible = "samsung,exynos3250-rtc",
 		.data = &s3c6410_rtc_data,
+	}, {
+		.compatible = "samsung,exynosautov9-rtc",
+		.data = &exynosautov9_rtc_data,
 	},
 	{ /* sentinel */ },
 };
-- 
2.34.1

Re: [PATCH v3 2/3] rtc: s3c: support for exynosautov9 on-chip RTC

[Henrik Grimler]

Hi Devang,

On Fri, Sep 05, 2025 at 04:35:53PM +0530, Devang Tailor wrote:
> The on-chip RTC of this SoC is almost similar to the previous version of
> SoCs except for S3C2410_TICNT tick time counter, which is used in this
> driver but not applicable for exynosautov9. So re-use the existing driver
> skipping disablement of S3C2410_TICNT in s3c24xx_rtc_disable() callback
> via a new boolean member of s3c_rtc_data.
> 
> This has been tested with 'hwclock' & 'date' utilities
> 
> Suggested-by: Henrik Grimler <henrik@grimler.se>
> Signed-off-by: Devang Tailor <dev.tailor@samsung.com>

Reviewed-by: Henrik Grimler <henrik@grimler.se>

Thank you, looks good!

Best regards,
Henrik Grimler

> ---
>  drivers/rtc/rtc-s3c.c | 21 ++++++++++++++++++---
>  1 file changed, 18 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/rtc/rtc-s3c.c b/drivers/rtc/rtc-s3c.c
> index 79b2a16f15ad..8fc5b4582b6d 100644
> --- a/drivers/rtc/rtc-s3c.c
> +++ b/drivers/rtc/rtc-s3c.c
> @@ -48,6 +48,7 @@ struct s3c_rtc {
>  
>  struct s3c_rtc_data {
>  	bool needs_src_clk;
> +	bool use_s3c2410_ticnt;
>  
>  	void (*irq_handler) (struct s3c_rtc *info, int mask);
>  	void (*enable) (struct s3c_rtc *info);
> @@ -369,9 +370,11 @@ static void s3c24xx_rtc_disable(struct s3c_rtc *info)
>  	con &= ~S3C2410_RTCCON_RTCEN;
>  	writew(con, info->base + S3C2410_RTCCON);
>  
> -	con = readb(info->base + S3C2410_TICNT);
> -	con &= ~S3C2410_TICNT_ENABLE;
> -	writeb(con, info->base + S3C2410_TICNT);
> +	if (info->data->use_s3c2410_ticnt) {
> +		con = readb(info->base + S3C2410_TICNT);
> +		con &= ~S3C2410_TICNT_ENABLE;
> +		writeb(con, info->base + S3C2410_TICNT);
> +	}
>  }
>  
>  static void s3c6410_rtc_disable(struct s3c_rtc *info)
> @@ -550,18 +553,21 @@ static void s3c6410_rtc_irq(struct s3c_rtc *info, int mask)
>  }
>  
>  static const struct s3c_rtc_data s3c2410_rtc_data = {
> +	.use_s3c2410_ticnt	= true,
>  	.irq_handler		= s3c24xx_rtc_irq,
>  	.enable			= s3c24xx_rtc_enable,
>  	.disable		= s3c24xx_rtc_disable,
>  };
>  
>  static const struct s3c_rtc_data s3c2416_rtc_data = {
> +	.use_s3c2410_ticnt	= true,
>  	.irq_handler		= s3c24xx_rtc_irq,
>  	.enable			= s3c24xx_rtc_enable,
>  	.disable		= s3c24xx_rtc_disable,
>  };
>  
>  static const struct s3c_rtc_data s3c2443_rtc_data = {
> +	.use_s3c2410_ticnt	= true,
>  	.irq_handler		= s3c24xx_rtc_irq,
>  	.enable			= s3c24xx_rtc_enable,
>  	.disable		= s3c24xx_rtc_disable,
> @@ -574,6 +580,12 @@ static const struct s3c_rtc_data s3c6410_rtc_data = {
>  	.disable		= s3c6410_rtc_disable,
>  };
>  
> +static const struct s3c_rtc_data exynosautov9_rtc_data = {
> +	.irq_handler		= s3c6410_rtc_irq,
> +	.enable			= s3c24xx_rtc_enable,
> +	.disable		= s3c24xx_rtc_disable,
> +};
> +
>  static const __maybe_unused struct of_device_id s3c_rtc_dt_match[] = {
>  	{
>  		.compatible = "samsung,s3c2410-rtc",
> @@ -590,6 +602,9 @@ static const __maybe_unused struct of_device_id s3c_rtc_dt_match[] = {
>  	}, {
>  		.compatible = "samsung,exynos3250-rtc",
>  		.data = &s3c6410_rtc_data,
> +	}, {
> +		.compatible = "samsung,exynosautov9-rtc",
> +		.data = &exynosautov9_rtc_data,
>  	},
>  	{ /* sentinel */ },
>  };
> -- 
> 2.34.1
> 

[PATCH v3 3/3] arm64: dts: exynosautov9: add RTC DT node

[Devang Tailor]

Add DT node for on-chip RTC for ExynosAutov9

Signed-off-by: Devang Tailor <dev.tailor@samsung.com>
Reviewed-by: Alim Akhtar <alim.akhtar@samsung.com>
---
 arch/arm64/boot/dts/exynos/exynosautov9-sadk.dts |  4 ++++
 arch/arm64/boot/dts/exynos/exynosautov9.dtsi     | 10 ++++++++++
 2 files changed, 14 insertions(+)

diff --git a/arch/arm64/boot/dts/exynos/exynosautov9-sadk.dts b/arch/arm64/boot/dts/exynos/exynosautov9-sadk.dts
index de2c1de51a76..5f5167571f7a 100644
--- a/arch/arm64/boot/dts/exynos/exynosautov9-sadk.dts
+++ b/arch/arm64/boot/dts/exynos/exynosautov9-sadk.dts
@@ -106,6 +106,10 @@ &pwm {
 	status = "okay";
 };
 
+&rtc {
+	status = "okay";
+};
+
 &serial_0 {
 	pinctrl-0 = <&uart0_bus_dual>;
 	status = "okay";
diff --git a/arch/arm64/boot/dts/exynos/exynosautov9.dtsi b/arch/arm64/boot/dts/exynos/exynosautov9.dtsi
index 66628cb32776..afa6b258153c 100644
--- a/arch/arm64/boot/dts/exynos/exynosautov9.dtsi
+++ b/arch/arm64/boot/dts/exynos/exynosautov9.dtsi
@@ -1633,6 +1633,16 @@ pwm: pwm@103f0000 {
 			clock-names = "timers";
 			status = "disabled";
 		};
+
+		rtc: rtc@10540000 {
+			compatible = "samsung,exynosautov9-rtc";
+			reg = <0x10540000 0x100>;
+			interrupts = <GIC_SPI 26 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 27 IRQ_TYPE_LEVEL_HIGH>;
+			clocks = <&xtcxo>;
+			clock-names = "rtc";
+			status = "disabled";
+		};
 	};
 };
 
-- 
2.34.1

Re: [PATCH v3 0/3] On-chip RTC support for ExynosAutov9

[Alexandre Belloni]

On 05/09/2025 16:35:51+0530, Devang Tailor wrote:
> Enable on-chip RTC support. The on-chip RTC of this SoC is similar
> to the previous version of Samsung SoCs except for TICNT tick time
> counter. So re-use the existing RTC driver with applicable call-backs
> for initialization and IRQ handling without accessing TICNT counter.
> 
> As suggested in review comment, instead of adding separate disable()
> call-back, re-used the existing s3c24xx_rtc_disable() by adding a new
> bool 'use_s3c2410_ticnt' in rtc_data to avoid accessing TICNT counter
> which is not valid for RTC of ExynosAutov9.
> 
> Setting and getting hardware clock has been tested using 'hwclock'
> and 'date' utilities.
> 
> Alarm interrupt has been checked with incrementing interrupt
> count via "cat /proc/interrupts | grep rtc" for 10sec
> wakeup time via "echo +10 > /sys/class/rtc/rtc0/wakealarm"
> 
> changelog
> ---
> Changes in v3:
> - 1/3 : Added Tag 'Reviewed-by'
> - 2/3 : Fixed the review comment of v2 to re-use the existing disable()
> 	instead of adding new one.
>       : Not adding Tag 'Reviewed-by' from V2 since the patch has been
> 	changed
> - 3/3 : Added Tag 'Reviewed-by'
> link for v2 : https://lore.kernel.org/linux-rtc/20250710083434.1821671-1-dev.tailor@samsung.com/
> 
> 
> Changes in v2:
> - Fixed the review comment of v1 for mis-aligmnent & asymmetry bit logic.
> - link for v1 : https://lore.kernel.org/linux-rtc/20250702052426.2404256-1-dev.tailor@samsung.com/
> 
> 
> Devang Tailor (3):
>   dt-bindings: rtc: s3c-rtc: add compatible for exynosautov9
>   rtc: s3c: support for exynosautov9 on-chip RTC
>   arm64: dts: exynosautov9: add RTC DT node
> 
>  .../devicetree/bindings/rtc/s3c-rtc.yaml      |  1 +
>  .../boot/dts/exynos/exynosautov9-sadk.dts     |  4 ++++
>  arch/arm64/boot/dts/exynos/exynosautov9.dtsi  | 10 +++++++++
>  drivers/rtc/rtc-s3c.c                         | 21 ++++++++++++++++---
>  4 files changed, 33 insertions(+), 3 deletions(-)
> 
> 
> base-commit: 4ac65880ebca1b68495bd8704263b26c050ac010

You should rebase on top of rtc-next as s3c2410 support has been
removed.


-- 
Alexandre Belloni, co-owner and COO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com