Add SD card controller infrastructure for SpacemiT K1 SoC with complete
pinctrl support for both standard and UHS modes.
- Add sdhci0 controller definition with clocks, resets and interrupts
- Add mmc1_cfg pinctrl for 3.3V standard SD operation
- Add mmc1_uhs_cfg pinctrl for 1.8V UHS high-speed operation
- Configure appropriate drive strength and power-source properties
This provides complete SD card infrastructure that K1-based boards can
enable.
Tested-by: Anand Moon <linux.amoon@gmail.com>
Tested-by: Trevor Gamblin <tgamblin@baylibre.com>
Signed-off-by: Iker Pedrosa <ikerpedrosam@gmail.com>
---
arch/riscv/boot/dts/spacemit/k1-pinctrl.dtsi | 40 ++++++++++++++++++++++++++++
arch/riscv/boot/dts/spacemit/k1.dtsi | 13 +++++++++
2 files changed, 53 insertions(+)
diff --git a/arch/riscv/boot/dts/spacemit/k1-pinctrl.dtsi b/arch/riscv/boot/dts/spacemit/k1-pinctrl.dtsi
index b13dcb10f4d66022d27307de73a6ea3287e97441..8d82011f1af666fb78c282a2abcc0cb88f962053 100644
--- a/arch/riscv/boot/dts/spacemit/k1-pinctrl.dtsi
+++ b/arch/riscv/boot/dts/spacemit/k1-pinctrl.dtsi
@@ -570,4 +570,44 @@ pwm14-1-pins {
drive-strength = <32>;
};
};
+
+ mmc1_cfg: mmc1-cfg {
+ mmc1-data-cmd-pins {
+ pinmux = <K1_PADCONF(104, 0)>, /* mmc1_d3 */
+ <K1_PADCONF(105, 0)>, /* mmc1_d2 */
+ <K1_PADCONF(106, 0)>, /* mmc1_d1 */
+ <K1_PADCONF(107, 0)>, /* mmc1_d0 */
+ <K1_PADCONF(108, 0)>; /* mmc1_cmd */
+ bias-pull-up = <1>;
+ drive-strength = <7>;
+ power-source = <3300>;
+ };
+
+ mmc1-clk-pins {
+ pinmux = <K1_PADCONF(109, 0)>; /* mmc1_clk */
+ bias-pull-down = <1>;
+ drive-strength = <7>;
+ power-source = <3300>;
+ };
+ };
+
+ mmc1_uhs_cfg: mmc1-uhs-cfg {
+ mmc1-data-cmd-pins {
+ pinmux = <K1_PADCONF(104, 0)>, /* mmc1_d3 */
+ <K1_PADCONF(105, 0)>, /* mmc1_d2 */
+ <K1_PADCONF(106, 0)>, /* mmc1_d1 */
+ <K1_PADCONF(107, 0)>, /* mmc1_d0 */
+ <K1_PADCONF(108, 0)>; /* mmc1_cmd */
+ bias-pull-up = <1>;
+ drive-strength = <13>;
+ power-source = <1800>;
+ };
+
+ mmc1-clk-pins {
+ pinmux = <K1_PADCONF(109, 0)>; /* mmc1_clk */
+ bias-pull-down = <1>;
+ drive-strength = <13>;
+ power-source = <1800>;
+ };
+ };
};
diff --git a/arch/riscv/boot/dts/spacemit/k1.dtsi b/arch/riscv/boot/dts/spacemit/k1.dtsi
index f0bad6855c970a609253d4b0ca2a4fcbf06bb8e3..28949f804610c60b7fa89d957507be32e3b49f34 100644
--- a/arch/riscv/boot/dts/spacemit/k1.dtsi
+++ b/arch/riscv/boot/dts/spacemit/k1.dtsi
@@ -1211,6 +1211,19 @@ emmc: mmc@d4281000 {
interrupts = <101>;
status = "disabled";
};
+
+ sdhci0: mmc@d4280000 {
+ compatible = "spacemit,k1-sdhci";
+ reg = <0x0 0xd4280000 0x0 0x200>;
+ clocks = <&syscon_apmu CLK_SDH_AXI>,
+ <&syscon_apmu CLK_SDH0>;
+ clock-names = "core", "io";
+ resets = <&syscon_apmu RESET_SDH_AXI>,
+ <&syscon_apmu RESET_SDH0>;
+ reset-names = "axi", "sdh";
+ interrupts = <99>;
+ status = "disabled";
+ };
};
};
};
--
2.53.0On Mon, Mar 30, 2026 at 16:38:06 CST, Iker Pedrosa wrote:
> Add SD card controller infrastructure for SpacemiT K1 SoC with complete
> pinctrl support for both standard and UHS modes.
>
> - Add sdhci0 controller definition with clocks, resets and interrupts
> - Add mmc1_cfg pinctrl for 3.3V standard SD operation
> - Add mmc1_uhs_cfg pinctrl for 1.8V UHS high-speed operation
> - Configure appropriate drive strength and power-source properties
>
> This provides complete SD card infrastructure that K1-based boards can
> enable.
>
> Tested-by: Anand Moon <linux.amoon@gmail.com>
> Tested-by: Trevor Gamblin <tgamblin@baylibre.com>
> Signed-off-by: Iker Pedrosa <ikerpedrosam@gmail.com>
> ---
> arch/riscv/boot/dts/spacemit/k1-pinctrl.dtsi | 40 ++++++++++++++++++++++++++++
> arch/riscv/boot/dts/spacemit/k1.dtsi | 13 +++++++++
> 2 files changed, 53 insertions(+)
>
> diff --git a/arch/riscv/boot/dts/spacemit/k1-pinctrl.dtsi b/arch/riscv/boot/dts/spacemit/k1-pinctrl.dtsi
> index b13dcb10f4d66022d27307de73a6ea3287e97441..8d82011f1af666fb78c282a2abcc0cb88f962053 100644
> --- a/arch/riscv/boot/dts/spacemit/k1-pinctrl.dtsi
> +++ b/arch/riscv/boot/dts/spacemit/k1-pinctrl.dtsi
> @@ -570,4 +570,44 @@ pwm14-1-pins {
> drive-strength = <32>;
> };
> };
> +
> + mmc1_cfg: mmc1-cfg {
> + mmc1-data-cmd-pins {
> + pinmux = <K1_PADCONF(104, 0)>, /* mmc1_d3 */
> + <K1_PADCONF(105, 0)>, /* mmc1_d2 */
> + <K1_PADCONF(106, 0)>, /* mmc1_d1 */
> + <K1_PADCONF(107, 0)>, /* mmc1_d0 */
> + <K1_PADCONF(108, 0)>; /* mmc1_cmd */
> + bias-pull-up = <1>;
> + drive-strength = <7>;
I'm a bit concerned about this value. Looking at the downstream 6.6 code, 3.3V uses DS4,
which equals 13mA. Since 7mA maps to DS0, what's the reasoning for using it here?
Do we have any documentation or measurement to back this up?
> + power-source = <3300>;
> + };
> +
> + mmc1-clk-pins {
> + pinmux = <K1_PADCONF(109, 0)>; /* mmc1_clk */
> + bias-pull-down = <1>;
> + drive-strength = <7>;
> + power-source = <3300>;
> + };
> + };
> +
> + mmc1_uhs_cfg: mmc1-uhs-cfg {
> + mmc1-data-cmd-pins {
> + pinmux = <K1_PADCONF(104, 0)>, /* mmc1_d3 */
> + <K1_PADCONF(105, 0)>, /* mmc1_d2 */
> + <K1_PADCONF(106, 0)>, /* mmc1_d1 */
> + <K1_PADCONF(107, 0)>, /* mmc1_d0 */
> + <K1_PADCONF(108, 0)>; /* mmc1_cmd */
> + bias-pull-up = <1>;
> + drive-strength = <13>;
See above.
- Troy
El lun, 30 mar 2026 a las 11:08, Troy Mitchell
(<troy.mitchell@linux.dev>) escribió:
>
> On Mon, Mar 30, 2026 at 16:38:06 CST, Iker Pedrosa wrote:
> > Add SD card controller infrastructure for SpacemiT K1 SoC with complete
> > pinctrl support for both standard and UHS modes.
> >
> > - Add sdhci0 controller definition with clocks, resets and interrupts
> > - Add mmc1_cfg pinctrl for 3.3V standard SD operation
> > - Add mmc1_uhs_cfg pinctrl for 1.8V UHS high-speed operation
> > - Configure appropriate drive strength and power-source properties
> >
> > This provides complete SD card infrastructure that K1-based boards can
> > enable.
> >
> > Tested-by: Anand Moon <linux.amoon@gmail.com>
> > Tested-by: Trevor Gamblin <tgamblin@baylibre.com>
> > Signed-off-by: Iker Pedrosa <ikerpedrosam@gmail.com>
> > ---
> > arch/riscv/boot/dts/spacemit/k1-pinctrl.dtsi | 40 ++++++++++++++++++++++++++++
> > arch/riscv/boot/dts/spacemit/k1.dtsi | 13 +++++++++
> > 2 files changed, 53 insertions(+)
> >
> > diff --git a/arch/riscv/boot/dts/spacemit/k1-pinctrl.dtsi b/arch/riscv/boot/dts/spacemit/k1-pinctrl.dtsi
> > index b13dcb10f4d66022d27307de73a6ea3287e97441..8d82011f1af666fb78c282a2abcc0cb88f962053 100644
> > --- a/arch/riscv/boot/dts/spacemit/k1-pinctrl.dtsi
> > +++ b/arch/riscv/boot/dts/spacemit/k1-pinctrl.dtsi
> > @@ -570,4 +570,44 @@ pwm14-1-pins {
> > drive-strength = <32>;
> > };
> > };
> > +
> > + mmc1_cfg: mmc1-cfg {
> > + mmc1-data-cmd-pins {
> > + pinmux = <K1_PADCONF(104, 0)>, /* mmc1_d3 */
> > + <K1_PADCONF(105, 0)>, /* mmc1_d2 */
> > + <K1_PADCONF(106, 0)>, /* mmc1_d1 */
> > + <K1_PADCONF(107, 0)>, /* mmc1_d0 */
> > + <K1_PADCONF(108, 0)>; /* mmc1_cmd */
> > + bias-pull-up = <1>;
> > + drive-strength = <7>;
> I'm a bit concerned about this value. Looking at the downstream 6.6 code, 3.3V uses DS4,
> which equals 13mA. Since 7mA maps to DS0, what's the reasoning for using it here?
> Do we have any documentation or measurement to back this up?
Thank you for catching this! You're absolutely right to question these
drive strength values.
Looking back at my development process, I remember hitting signal
integrity issues in the early stages of this driver development. As a
quick solution, I lowered the drive strength values, which seemed to
resolve the immediate problems, and I moved on without revisiting the
electrical characteristics.
After your feedback, I investigated this properly by comparing with
the vendor kernel. It uses:
- 3.3V mode: PAD_3V_DS4 (19mA)
- 1.8V UHS mode: PAD_1V8_DS3 (42mA)
My original values were indeed backwards from both electrical theory
and proven vendor implementation. Testing with the corrected values
(19mA/42mA) confirms SD card is working.
I'll send v6 with the corrected drive strength values: drive-strength
= <19> for 3.3V and drive-strength = <42> for 1.8V UHS modes.
> > + power-source = <3300>;
> > + };
> > +
> > + mmc1-clk-pins {
> > + pinmux = <K1_PADCONF(109, 0)>; /* mmc1_clk */
> > + bias-pull-down = <1>;
> > + drive-strength = <7>;
> > + power-source = <3300>;
> > + };
> > + };
> > +
> > + mmc1_uhs_cfg: mmc1-uhs-cfg {
> > + mmc1-data-cmd-pins {
> > + pinmux = <K1_PADCONF(104, 0)>, /* mmc1_d3 */
> > + <K1_PADCONF(105, 0)>, /* mmc1_d2 */
> > + <K1_PADCONF(106, 0)>, /* mmc1_d1 */
> > + <K1_PADCONF(107, 0)>, /* mmc1_d0 */
> > + <K1_PADCONF(108, 0)>; /* mmc1_cmd */
> > + bias-pull-up = <1>;
> > + drive-strength = <13>;
> See above.
>
> - Troy
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