* Re: [PATCH 1/1] riscv: dts: sophgo: enable hardware clock (RTC) on the Milk-V Pioneer
2026-01-05 12:01 ` [PATCH 1/1] riscv: dts: sophgo: enable " Michael Orlitzky
@ 2026-01-05 12:07 ` Krzysztof Kozlowski
2026-01-06 2:10 ` Chen Wang
1 sibling, 0 replies; 4+ messages in thread
From: Krzysztof Kozlowski @ 2026-01-05 12:07 UTC (permalink / raw)
To: Michael Orlitzky, unicorn_wang, inochiama
Cc: robh, krzk+dt, conor+dt, pjw, palmer, aou, alex, devicetree,
sophgo, linux-riscv
On 05/01/2026 13:01, Michael Orlitzky wrote:
> These boards have a working hardware clock if you put a CR-1220
> battery in them. Let's enable it:
>
> 1. Enable the (already defined) i2c0 by overriding the default
> status = "disabled" with "okay".
Do not describe the diff. This is obvious. Explain WHY you are doing all
this.
>
> 2. Define the rtc on &i2c0. This is more or less the example from the
> documentation (devicetree/bindings/rtc/rtc-ds1307.yaml), and it was
> present in the same form in an earlier 6.1.x vendor kernel.
>
> 3. Copy the pinctrl stuff from &i2c1 and update the PINMUX constants
> with the IIC0 values from dt-bindings/pinctrl/pinctrl-sg2042.h.
Drop, irrelevant.
>
> Afterwards, the new I2C and RTC can be enabled with,
>
> * CONFIG_I2C_DESIGNWARE_CORE=y
> * CONFIG_I2C_DESIGNWARE_PLATFORM=y
> * CONFIG_RTC_DRV_DS1307=y
Drop, irrelevant. You describe here hardware, not Linux kernel config.
>
> The new I2C should appear under /sys/devices/platform/soc, and with
> any luck you'll have a clock the next time you boot:
>
> [ T367] rtc-ds1307 5-0068: registered as rtc0
> [ T367] rtc-ds1307 5-0068: setting system clock to ...
Drop, obvious.
>
> Signed-off-by: Michael Orlitzky <michael@orlitzky.com>
> ---
> .../boot/dts/sophgo/sg2042-milkv-pioneer.dts | 21 +++++++++++++++++++
> 1 file changed, 21 insertions(+)
>
Best regards,
Krzysztof
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* Re: [PATCH 1/1] riscv: dts: sophgo: enable hardware clock (RTC) on the Milk-V Pioneer
2026-01-05 12:01 ` [PATCH 1/1] riscv: dts: sophgo: enable " Michael Orlitzky
2026-01-05 12:07 ` Krzysztof Kozlowski
@ 2026-01-06 2:10 ` Chen Wang
1 sibling, 0 replies; 4+ messages in thread
From: Chen Wang @ 2026-01-06 2:10 UTC (permalink / raw)
To: Michael Orlitzky, inochiama
Cc: robh, krzk+dt, conor+dt, pjw, palmer, aou, alex, devicetree,
sophgo, linux-riscv
On 1/5/2026 8:01 PM, Michael Orlitzky wrote:
> These boards have a working hardware clock if you put a CR-1220
> battery in them. Let's enable it:
>
> 1. Enable the (already defined) i2c0 by overriding the default
> status = "disabled" with "okay".
>
> 2. Define the rtc on &i2c0. This is more or less the example from the
> documentation (devicetree/bindings/rtc/rtc-ds1307.yaml), and it was
> present in the same form in an earlier 6.1.x vendor kernel.
>
> 3. Copy the pinctrl stuff from &i2c1 and update the PINMUX constants
> with the IIC0 values from dt-bindings/pinctrl/pinctrl-sg2042.h.
>
> Afterwards, the new I2C and RTC can be enabled with,
>
> * CONFIG_I2C_DESIGNWARE_CORE=y
> * CONFIG_I2C_DESIGNWARE_PLATFORM=y
> * CONFIG_RTC_DRV_DS1307=y
>
> The new I2C should appear under /sys/devices/platform/soc, and with
> any luck you'll have a clock the next time you boot:
>
> [ T367] rtc-ds1307 5-0068: registered as rtc0
> [ T367] rtc-ds1307 5-0068: setting system clock to ...
>
> Signed-off-by: Michael Orlitzky <michael@orlitzky.com>
> ---
> .../boot/dts/sophgo/sg2042-milkv-pioneer.dts | 21 +++++++++++++++++++
> 1 file changed, 21 insertions(+)
>
> diff --git a/arch/riscv/boot/dts/sophgo/sg2042-milkv-pioneer.dts b/arch/riscv/boot/dts/sophgo/sg2042-milkv-pioneer.dts
> index 54d8386bf9c0..ecf8c1e29079 100644
> --- a/arch/riscv/boot/dts/sophgo/sg2042-milkv-pioneer.dts
> +++ b/arch/riscv/boot/dts/sophgo/sg2042-milkv-pioneer.dts
> @@ -52,6 +52,17 @@ &emmc {
> status = "okay";
> };
>
> +&i2c0 {
> + pinctrl-0 = <&i2c0_cfg>;
> + pinctrl-names = "default";
> + status = "okay";
> +
> + rtc: rtc@68 {
> + compatible = "dallas,ds1307";
> + reg = <0x68>;
> + };
> +};
> +
> &i2c1 {
> pinctrl-0 = <&i2c1_cfg>;
> pinctrl-names = "default";
> @@ -89,6 +100,16 @@ sdhci-emmc-rst-pwr-pins {
> };
> };
>
> + i2c0_cfg: i2c0-cfg {
> + i2c0-pins {
> + pinmux = <PINMUX(PIN_IIC0_SDA, 0)>,
> + <PINMUX(PIN_IIC0_SCL, 0)>;
> + bias-pull-up;
> + drive-strength-microamp = <26800>;
> + input-schmitt-enable;
> + };
> + };
> +
> i2c1_cfg: i2c1-cfg {
> i2c1-pins {
> pinmux = <PINMUX(PIN_IIC1_SDA, 0)>,
DTS changes LGTM.
Reviewed-by: Chen Wang <unicorn_wang@outlook.com>
For commit description issues, please refer to Krzysztof's suggestions.
Thanks,
Chen
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