背景
根据orangepi zero2用户手册说明，linux5.13内核不能使用 modprobe fbtft_device 驱动spi lcd
查看linux内核源码提交记录，发现在v5.4-rc3中删除了fbtft_device.c文件
commit如下
shell
staging/fbtft: Remove fbtft_device
Commit c440eee ("Staging: fbtft: Switch to the gpio descriptor
interface") removed the gpio code from fbtft_device rendering it useless.
fbtft_device is a module that was used on the Raspberry Pi to dynamically
add fbtft devices when the Pi didn't have Device Tree support.
Just remove the module since it's the responsibility of Device Tree, ACPI
or platform code to add devices.
Fixes: c440eee ("Staging: fbtft: Switch to the gpio descriptor interface")
Signed-off-by: Noralf Trønnes <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>"fbtft_device用来在树莓派没有设备树时，自动添加fbtft设备，删除这个模块因为添加设备是设备树、ACPI或者平台代码的责任"
所以是因为原来的代码不符合设备和驱动分离的原则，所以给删除了，但其实驱动程序依然在，理论上只需要将设备硬件信息注册到内核，就可以正常运行了，可以通过设备树或者模块
dts
下面看下orangepi官方修改后的内核源码中的设备树，分支orange-pi-6.1-sun50iw9
https://github.com/orangepi-xunlong/linux-orangepi
sun50i-h616.dtsi
从芯片级（h616）的dts可以看到spi有spi0和spi1，spi0有一个cs0，spi1有cs0和cs1
shell
/omit-if-no-ref/
spi0_pins: spi0-pins {
pins = "PC0", "PC2", "PC4";
function = "spi0";
};
/omit-if-no-ref/
spi0_cs0_pin: spi0-cs0-pin {
pins = "PC3";
function = "spi0";
};
/omit-if-no-ref/
spi1_pins: spi1-pins {
pins = "PH6", "PH7", "PH8";
function = "spi1";
};
/omit-if-no-ref/
spi1_cs0_pin: spi1-cs0-pin {
pins = "PH5";
function = "spi1";
};
/omit-if-no-ref/
spi1_cs1_pin: spi1-cs1-pin {
pins = "PH9";
function = "spi1";
};spi1设备只添加了cs1，cs0引脚没有用在spi1上，而是复用在了i2c3
shell
spi0: spi@5010000 {
compatible = "allwinner,sun50i-h616-spi",
"allwinner,sun8i-h3-spi";
reg = <0x05010000 0x1000>;
interrupts = <GIC_SPI 12 IRQ_TYPE_LEVEL_HIGH>;
clocks = <&ccu CLK_BUS_SPI0>, <&ccu CLK_SPI0>;
clock-names = "ahb", "mod";
resets = <&ccu RST_BUS_SPI0>;
pinctrl-names = "default";
pinctrl-0 = <&spi0_pins>;
dmas = <&dma 22>, <&dma 22>;
dma-names = "rx", "tx";
status = "disabled";
#address-cells = <1>;
#size-cells = <0>;
};
spi1: spi@5011000 {
compatible = "allwinner,sun50i-h616-spi",
"allwinner,sun8i-h3-spi";
reg = <0x05011000 0x1000>;
interrupts = <GIC_SPI 13 IRQ_TYPE_LEVEL_HIGH>;
clocks = <&ccu CLK_BUS_SPI1>, <&ccu CLK_SPI1>;
clock-names = "ahb", "mod";
resets = <&ccu RST_BUS_SPI1>;
pinctrl-names = "default";
pinctrl-0 = <&spi1_pins>, <&spi1_cs1_pin>;
dmas = <&dma 23>, <&dma 23>;
dma-names = "rx", "tx";
status = "disabled";
#address-cells = <1>;
#size-cells = <0>;
};sun50i-h616-orangepi-zero2.dts
从板级（orangepi zero2）dts可以看到添加了一个spidev@1设备，但是默认未启用
shell
&spi1 {
status = "disabled";
#address-cells = <1>;
#size-cells = <0>;
pinctrl-names = "default";
pinctrl-0 = <&spi1_pins>, <&spi1_cs1_pin>;
spidev@1 {
compatible = "rohm,dh2228fv";
status = "disabled";
reg = <1>;
spi-max-frequency = <1000000>;
};
};硬件
可以看到spi0用来连接NOR FLASH，所以肯定不可以再用来连接lcd了
spi1在26PIN引出，并且cs0和cs1都有，不过cs0复用在了i2c3的TWI3-SDA引脚上，所以我们使用spi1驱动lcd，并且使用cs1
硬件接线如下，实际上就是用户手册推荐的连接
dts替换
新建ili9341.dts文件
vim ili9341.dts
shell
/dts-v1/;
/plugin/;
/ {
fragment@0 {
target = <&spi1>;
__overlay__ {
status = "okay";
ili9341: ili9341@0 {
compatible = "ilitek,ili9341";
reg = <1>;
spi-max-frequency = <40000000>;
rotate = <0>;
bgr;
fps = <30>;
buswidth = <8>;
reset-gpios = <&pio 2 9 1>;
dc-gpios = <&pio 2 6 0>;
led-gpios = <&pio 2 5 0>;
debug = <0>;
};
};
};
};替换设备树，执行后reboot
orangepi-add-overlay ili9341.dts
不出意外的话，console默认会显示在lcd上，可以使用fbi指令测试
shell
su root
apt update
apt install fbi
fbi -vt 1 -noverbose -d /dev/fb0 /boot/boot.bmp
关于pinctrl-0和cs-gpios
使用cs-gpios定义片选信号使用的引脚，来自ChatGPT3.5
shell
spi@40013000 {
compatible = "some-vendor,spi-bus";
reg = <0x40013000>;
#address-cells = <1>;
#size-cells = <0>;
status = "okay";
cs-gpios = <&gpio1 10 0>, <&gpio1 11 0>; // 定义两个片选 GPIO
spidev0: spidev@0 {
compatible = "some-vendor,spidev";
reg = <0>; // 对应 cs-gpios 的第一个 GPIO (gpio1 10)
spi-max-frequency = <10000000>;
status = "okay";
};
spidev1: spidev@1 {
compatible = "some-vendor,spidev";
reg = <1>; // 对应 cs-gpios 的第二个 GPIO (gpio1 11)
spi-max-frequency = <10000000>;
status = "okay";
};
};pinctrl-0已经包含了spi1_cs1_pin，所以spidev的reg直接使用1也可以找到，就不需要cs-gpios了
shell
&spi1 {
status = "disabled";
#address-cells = <1>;
#size-cells = <0>;
pinctrl-names = "default";
pinctrl-0 = <&spi1_pins>, <&spi1_cs1_pin>;
spidev@1 {
compatible = "rohm,dh2228fv";
status = "disabled";
reg = <1>;
spi-max-frequency = <1000000>;
};
};