Question regarding Linux-6.3.5 and Sunxi A20 NAND/NFC support

Fawad Lateef fawadlateef at gmail.com
Sun Aug 13 19:40:26 EDT 2023 

Hi,

I am trying to make Linux-6.3.5 working on Olimex/Sunxi A20 SOM with NAND.

Found that the Sunxi A20 NAND is supported in mainline kernel
(drivers/mtd/nand/raw/sunxi_nand.c) and following the guidelines here
(https://linux-sunxi.org/Mainline_NAND_Howto); I added the NFC chip
pin information in sunxi-a20.dtsi and defined/enabled the nfc
controller in the sunxi-a20-olinuxino-micro.dts files.

The changes I made are below. Problem is when I define the nfc node
entry in dts file "without" pinctrl entry (pinctrl-0 = <&nand_pins_a>,
<&nand_cs0_pins_a>, <&nand_rb0_pins_a>;), the sunxi_nfc_probe function
is called (though the No NAND chip is detected).

And if I define the pinctrl-0  in the nfc node, all I see related to
NAND/sunxi in the kernel boot log is this line:  platform
1c03000.nand-controller: deferred probe pending.

Can someone please guide me why the deferred probe is pending but
never call the sunxi_nfc_probe function?  And without pinctrl-0 entry
why probe function is being called?

Seems like I am missing something basic here and any pointers to debug
this will be appreciated.


--- linux-6.3.5.orig/arch/arm/boot/dts/sun7i-a20-olinuxino-micro.dts
2023-05-30 14:17:29.000000000 +0100
+++ linux-6.3.5/arch/arm/boot/dts/sun7i-a20-olinuxino-micro.dts
2023-08-13 23:27:22.405058025 +0100
@@ -56,7 +56,7 @@

  aliases {
  serial0 = &uart0;
- serial1 = &uart6;
+ serial1 = &uart2;
  serial2 = &uart7;
  spi0 = &spi1;
  spi1 = &spi2;
@@ -66,17 +66,6 @@
  stdout-path = "serial0:115200n8";
  };

- hdmi-connector {
- compatible = "hdmi-connector";
- type = "a";
-
- port {
- hdmi_con_in: endpoint {
- remote-endpoint = <&hdmi_out_con>;
- };
- };
- };
-
  leds {
  compatible = "gpio-leds";
  pinctrl-names = "default";
@@ -90,16 +79,55 @@
  };
 };

-&ahci {
- target-supply = <&reg_ahci_5v>;
+&nfc {
+ pinctrl-names = "default";
+ pinctrl-0 = <&nand_pins_a>, <&nand_cs0_pins_a>, <&nand_rb0_pins_a>;
  status = "okay";
+
+ nand at 0 {
+ #address-cells = <2>;
+ #size-cells = <2>;
+ reg = <0>;
+ allwinner,rb = <0>;
+
+ nand-ecc-mode = "hw";
+ nand-on-flash-bbt;
+ };
+
+ boot0 at 0 {
+ label = "boot0";
+ reg = /bits/ 64 <0x0 0x200000>;
+ };
+
+ boot0-rescue at 200000 {
+ label = "boot0-rescue";
+ reg = /bits/ 64 <0x200000 0x200000>;
+ };
+
+ uboot at 400000 {
+ label = "uboot";
+ reg = /bits/ 64 <0x400000 0x200000>;
+ };
+
+ uboot-rescue at 600000 {
+ label = "uboot-rescue";
+ reg = /bits/ 64 <0x600000 0x200000>;
+ };
+
+ main at 800000 {
+ label = "main";
+ reg = /bits/ 64 <0x800000 0xff800000>;
+ };
+
 };

-&codec {
+&ahci {
+ target-supply = <&reg_ahci_5v>;
  status = "okay";
 };

 &cpu0 {
+ clock-frequency = <900000000>;
  cpu-supply = <&reg_dcdc2>;
 };

@@ -123,34 +151,24 @@
  status = "okay";
 };

-&hdmi {
- status = "okay";
-};
-
-&hdmi_out {
- hdmi_out_con: endpoint {
- remote-endpoint = <&hdmi_con_in>;
- };
-};
-
 &i2c0 {
- status = "okay";
+        status = "okay";

- axp209: pmic at 34 {
- reg = <0x34>;
- interrupt-parent = <&nmi_intc>;
- interrupts = <0 IRQ_TYPE_LEVEL_LOW>;
- };
+        axp209: pmic at 34 {
+                reg = <0x34>;
+                interrupt-parent = <&nmi_intc>;
+                interrupts = <0 IRQ_TYPE_LEVEL_LOW>;
+        };
 };

 &i2c1 {
- status = "okay";
+        status = "okay";

- eeprom: eeprom at 50 {
- compatible = "atmel,24c16";
- reg = <0x50>;
- pagesize = <16>;
- };
+        eeprom: eeprom at 50 {
+                compatible = "atmel,24c16";
+                reg = <0x50>;
+                pagesize = <16>;
+        };
 };

 &i2c2 {
@@ -160,55 +178,6 @@
 &lradc {
  vref-supply = <&reg_vcc3v0>;
  status = "okay";
-
- button-191 {
- label = "Volume Up";
- linux,code = <KEY_VOLUMEUP>;
- channel = <0>;
- voltage = <191274>;
- };
-
- button-392 {
- label = "Volume Down";
- linux,code = <KEY_VOLUMEDOWN>;
- channel = <0>;
- voltage = <392644>;
- };
-
- button-601 {
- label = "Menu";
- linux,code = <KEY_MENU>;
- channel = <0>;
- voltage = <601151>;
- };
-
- button-795 {
- label = "Search";
- linux,code = <KEY_SEARCH>;
- channel = <0>;
- voltage = <795090>;
- };
-
- button-987 {
- label = "Home";
- linux,code = <KEY_HOMEPAGE>;
- channel = <0>;
- voltage = <987387>;
- };
-
- button-1184 {
- label = "Esc";
- linux,code = <KEY_ESC>;
- channel = <0>;
- voltage = <1184678>;
- };
-
- button-1398 {
- label = "Enter";
- linux,code = <KEY_ENTER>;
- channel = <0>;
- voltage = <1398804>;
- };
 };

 &gmac_mdio {
@@ -239,10 +208,6 @@
  status = "okay";
 };

-&otg_sram {
- status = "okay";
-};
-
 &pio {
  gmac_txerr: gmac-txerr-pin {
  pins = "PA17";
@@ -323,9 +288,9 @@
  status = "okay";
 };

-&uart6 {
+&uart2 {
  pinctrl-names = "default";
- pinctrl-0 = <&uart6_pi_pins>;
+ pinctrl-0 = <&uart2_pi_pins>;
  status = "okay";
 };

@@ -352,3 +317,28 @@
  usb2_vbus-supply = <&reg_usb2_vbus>;
  status = "okay";
 };
+
+&fe0 {
+ status = "disabled";
+};
+
+&fe1 {
+ status = "disabled";
+};
+
+&be0 {
+ status = "disabled";
+};
+
+&be1 {
+ status = "disabled";
+};
+
+&tcon0 {
+ status = "disabled";
+};
+
+&tcon1 {
+ status = "disabled";
+};
+


--- linux-6.3.5.orig/arch/arm/boot/dts/sun7i-a20.dtsi 2023-05-30
14:17:29.000000000 +0100
+++ linux-6.3.5/arch/arm/boot/dts/sun7i-a20.dtsi 2023-08-08
00:30:04.689288733 +0100
@@ -345,6 +345,58 @@
  #size-cells = <0>;
  };

+ nand_pins_a: nand_base0 at 0 {
+ allwinner,pins = "PC0", "PC1", "PC2",
+ "PC5", "PC8", "PC9", "PC10",
+ "PC11", "PC12", "PC13", "PC14",
+ "PC15", "PC16";
+ allwinner,function = "nand0";
+ allwinner,drive = <SUN4I_PINCTRL_10_MA>;
+ allwinner,pull = <SUN4I_PINCTRL_NO_PULL>;
+ };
+
+ nand_cs0_pins_a: nand_cs at 0 {
+ allwinner,pins = "PC4";
+ allwinner,function = "nand0";
+ allwinner,drive = <SUN4I_PINCTRL_10_MA>;
+ allwinner,pull = <SUN4I_PINCTRL_NO_PULL>;
+ };
+
+ nand_cs1_pins_a: nand_cs at 1 {
+ allwinner,pins = "PC3";
+ allwinner,function = "nand0";
+ allwinner,drive = <SUN4I_PINCTRL_10_MA>;
+ allwinner,pull = <SUN4I_PINCTRL_NO_PULL>;
+ };
+
+ nand_cs2_pins_a: nand_cs at 2 {
+ allwinner,pins = "PC17";
+ allwinner,function = "nand0";
+ allwinner,drive = <SUN4I_PINCTRL_10_MA>;
+ allwinner,pull = <SUN4I_PINCTRL_NO_PULL>;
+ };
+
+ nand_cs3_pins_a: nand_cs at 3 {
+ allwinner,pins = "PC18";
+ allwinner,function = "nand0";
+ allwinner,drive = <SUN4I_PINCTRL_10_MA>;
+ allwinner,pull = <SUN4I_PINCTRL_NO_PULL>;
+ };
+
+ nand_rb0_pins_a: nand_rb at 0 {
+ allwinner,pins = "PC6";
+ allwinner,function = "nand0";
+ allwinner,drive = <SUN4I_PINCTRL_10_MA>;
+ allwinner,pull = <SUN4I_PINCTRL_NO_PULL>;
+ };
+
+ nand_rb1_pins_a: nand_rb at 1 {
+ allwinner,pins = "PC7";
+ allwinner,function = "nand0";
+ allwinner,drive = <SUN4I_PINCTRL_10_MA>;
+ allwinner,pull = <SUN4I_PINCTRL_NO_PULL>;
+ };
+
  spi0: spi at 1c05000 {
  compatible = "allwinner,sun4i-a10-spi";
  reg = <0x01c05000 0x1000>;


Thanks and regards,

-- Fawad Lateef
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