From: Jan Dakinevich <yvdakinevich@sberdevices.ru>

The definition is inspired by a similar one for AXG SoC family.
'sdio_pins' and 'sdio_clk_gate_pins' pinctrls are supposed to be used as
"default" and "clk-gate" in board-specific device trees.

'meson-gx' driver during initialization sets clock to safe low-frequency
value (400kHz). However, both source clocks ("clkin0" and "clkin1") are
high-frequency by default, and using of eMMC's internal divider is not
enough to achieve so low values. To provide low-frequency source,
reparent "sd_emmc_sel2" clock using 'assigned-clocks' property.

Signed-off-by: Jan Dakinevich <yvdakinevich@sberdevices.ru>
Signed-off-by: Dmitry Rokosov <ddrokosov@sberdevices.ru>
---
 arch/arm64/boot/dts/amlogic/meson-a1.dtsi | 43 +++++++++++++++++++++++
 1 file changed, 43 insertions(+)

diff --git a/arch/arm64/boot/dts/amlogic/meson-a1.dtsi b/arch/arm64/boot/dts/amlogic/meson-a1.dtsi
index 3eb6aa9c00e0..a25170c61462 100644
--- a/arch/arm64/boot/dts/amlogic/meson-a1.dtsi
+++ b/arch/arm64/boot/dts/amlogic/meson-a1.dtsi
@@ -134,6 +134,32 @@ mux {
 						bias-pull-down;
 					};
 				};
+
+				sdio_pins: sdio {
+					mux-0 {
+						groups = "sdcard_d0_x",
+							 "sdcard_d1_x",
+							 "sdcard_d2_x",
+							 "sdcard_d3_x",
+							 "sdcard_cmd_x";
+						function = "sdcard";
+						bias-pull-up;
+					};
+
+					mux-1 {
+						groups = "sdcard_clk_x";
+						function = "sdcard";
+						bias-disable;
+					};
+				};
+
+				sdio_clk_gate_pins: sdio_clk_gate {
+					mux {
+						groups = "sdcard_clk_x";
+						function = "sdcard";
+						bias-pull-down;
+					};
+				};
 			};
 
 			uart_AO: serial@1c00 {
@@ -200,6 +226,23 @@ usb2_phy1: phy@4000 {
 				#phy-cells = <0>;
 				power-domains = <&pwrc PWRC_USB_ID>;
 			};
+
+			sd_emmc: sd@10000 {
+				compatible = "amlogic,meson-axg-mmc";
+				reg = <0x0 0x10000 0x0 0x800>;
+				interrupts = <GIC_SPI 58 IRQ_TYPE_LEVEL_HIGH>;
+				clocks = <&clkc_periphs CLKID_SD_EMMC_A>,
+					 <&clkc_periphs CLKID_SD_EMMC>,
+					 <&clkc_pll CLKID_FCLK_DIV2>;
+				clock-names = "core",
+					      "clkin0",
+					      "clkin1";
+				assigned-clocks = <&clkc_periphs CLKID_SD_EMMC_SEL2>;
+				assigned-clock-parents = <&xtal>;
+				resets = <&reset RESET_SD_EMMC_A>;
+				power-domains = <&pwrc PWRC_SD_EMMC_ID>;
+				status = "disabled";
+			};
 		};
 
 		gic: interrupt-controller@ff901000 {
-- 
2.36.0

On Wed, Jun 7, 2023 at 10:16 PM Dmitry Rokosov <ddrokosov@sberdevices.ru> wrote:
>
> From: Jan Dakinevich <yvdakinevich@sberdevices.ru>
>
> The definition is inspired by a similar one for AXG SoC family.
> 'sdio_pins' and 'sdio_clk_gate_pins' pinctrls are supposed to be used as
> "default" and "clk-gate" in board-specific device trees.
Let's wait for Neil's response on the other patch for the question
about pin mux settings

> 'meson-gx' driver during initialization sets clock to safe low-frequency
> value (400kHz). However, both source clocks ("clkin0" and "clkin1") are
> high-frequency by default, and using of eMMC's internal divider is not
> enough to achieve so low values. To provide low-frequency source,
> reparent "sd_emmc_sel2" clock using 'assigned-clocks' property.
Even if the pinctrl part should be postponed then I think it's worth
adding &sd_emmc

Hi,

On 25/06/2023 23:11, Martin Blumenstingl wrote:
> On Wed, Jun 7, 2023 at 10:16 PM Dmitry Rokosov <ddrokosov@sberdevices.ru> wrote:
>>
>> From: Jan Dakinevich <yvdakinevich@sberdevices.ru>
>>
>> The definition is inspired by a similar one for AXG SoC family.
>> 'sdio_pins' and 'sdio_clk_gate_pins' pinctrls are supposed to be used as
>> "default" and "clk-gate" in board-specific device trees.
> Let's wait for Neil's response on the other patch for the question
> about pin mux settings
> 
>> 'meson-gx' driver during initialization sets clock to safe low-frequency
>> value (400kHz). However, both source clocks ("clkin0" and "clkin1") are
>> high-frequency by default, and using of eMMC's internal divider is not
>> enough to achieve so low values. To provide low-frequency source,
>> reparent "sd_emmc_sel2" clock using 'assigned-clocks' property.
> Even if the pinctrl part should be postponed then I think it's worth
> adding &sd_emmc

Yeah it's weird to add HW definition and to not enable them,
so please enable them in the board if you add them in the DTSI.

Neil

Hello Neil,

Thank you for the review!

On Mon, Jun 26, 2023 at 03:36:23PM +0200, neil.armstrong@linaro.org wrote:
> Hi,
> 
> On 25/06/2023 23:11, Martin Blumenstingl wrote:
> > On Wed, Jun 7, 2023 at 10:16 PM Dmitry Rokosov <ddrokosov@sberdevices.ru> wrote:
> > > 
> > > From: Jan Dakinevich <yvdakinevich@sberdevices.ru>
> > > 
> > > The definition is inspired by a similar one for AXG SoC family.
> > > 'sdio_pins' and 'sdio_clk_gate_pins' pinctrls are supposed to be used as
> > > "default" and "clk-gate" in board-specific device trees.
> > Let's wait for Neil's response on the other patch for the question
> > about pin mux settings
> > 
> > > 'meson-gx' driver during initialization sets clock to safe low-frequency
> > > value (400kHz). However, both source clocks ("clkin0" and "clkin1") are
> > > high-frequency by default, and using of eMMC's internal divider is not
> > > enough to achieve so low values. To provide low-frequency source,
> > > reparent "sd_emmc_sel2" clock using 'assigned-clocks' property.
> > Even if the pinctrl part should be postponed then I think it's worth
> > adding &sd_emmc
> 
> Yeah it's weird to add HW definition and to not enable them,
> so please enable them in the board if you add them in the DTSI.

Unfortunately, I'm unable to provide our internal board DTS. However, I
have an AD401 reference board on hand, so it's possible to test
everything there. I'll include these changes in the next version.

-- 
Thank you,
Dmitry