请问 uboot 不能驱动PWM7 (PD22) 是什么原因呢？

whycan晕哥 LV 9

uboot-board.dts：

&pwm7_pin_a {
        pins = "PD22";
        function = "pwm7";
        allwinner,muxsel = <5>;
        drive-strength = <10>;
        bias-pull-up;
};

&pwm7_pin_b {
        pins = "PD22";
        muxsel = <0>;
        function = "gpio_in";
};

&pwm7 {
        pinctrl-names = "active", "sleep";
        pinctrl-0 = <&pwm7_pin_a>;
        pinctrl-1 = <&pwm7_pin_b>;
        status = "okay";
};

或者：

&pio {
        pwm7_pin_a: pwm7@0 {
                pins = "PD22";
                function = "pwm7";
                drive-strength = <10>;
                bias-pull-up;
        };

        pwm7_pin_b: pwm7@1 {
                pins = "PD22";
                function = "gpio_in";
        };
};

&pwm7 {
        pinctrl-names = "active", "sleep";
        pinctrl-0 = <&pwm7_pin_a>;
        pinctrl-1 = <&pwm7_pin_b>;
        status = "okay";
};

LCD0配置：

&lcd0 {
...
lcd_backlight = <100>;
lcd_pwm_used = <1>;
lcd_pwm_ch = <7>;
lcd_pwm_freq = <9000>;
lcd_pwm_pol = <1>;
...
}

日志：

U-Boot 2018.05-g0a88ac9-dirty-config-dirty (Jan 14 2022 - 08:49:40 +0800) Allwinner Technology

[00.273]DRAM:  64 MiB
[00.275]Relocation Offset is: 01f02000
[00.279]secure enable bit: 0
[00.282]CPU=1008 MHz,PLL6=600 Mhz,AHB=200 Mhz, APB1=100Mhz  MBus=300Mhz
[00.288]flash init start
[00.290]workmode = 0,storage type = 1
[00.294][mmc]: mmc driver ver uboot2018:2021-04-16 14:23:00-1
[00.299][mmc]: get sdc_type fail and use default host:tm1.
[00.306][mmc]: can't find node "mmc0",will add new node
[00.310][mmc]: fdt err returned <no error>
[00.314][mmc]: Using default timing para
[00.318][mmc]: SUNXI SDMMC Controller Version:0x50310
[00.336][mmc]: card_caps:0x3000000a
[00.339][mmc]: host_caps:0x3000003f
[00.343]sunxi flash init ok
[00.345]line:714 init_clocks
__clk_init: clk pll_periph0x2 already initialized
register fix_factor clk error
[00.355]drv_disp_init
request pwm success, pwm7:pwm7:0x2000c00.
[00.370]###LCD init
[00.372]drv_disp_init finish
[00.374]boot_gui_init:start
[00.377]set disp.dev2_output_type fail. using defval=0
[00.382]I80_HX8537 NO info[00.386]I80_HX8537 POWER ON[00.408]boot_gui_init:finish
[00.578]I80_HX8537 INITED ![00.757]hx8357 inited[00.759]hx8357 inited[00.761]hx8357 inited[00.763]hx8357 inited[00.764]hx8357 inited[00.766]hx8357 initedpartno erro : can't find partition bootloader
54 bytes read in 2 ms (26.4 KiB/s)
[00.784]bmp_name=bootlogo.bmp size 307254
307254 bytes read in 15 ms (19.5 MiB/s)
[00.823]Loading Environment from SUNXI_FLASH... OK
[00.843]out of usb burn from boot: not need burn key
root_partition is rootfs
set root to /dev/mmcblk0p5
[00.853]update part info
[00.857]update bootcmd
[00.860]change working_fdt 0x42ac1da8 to 0x42aa1da8
[00.882]update dts
Hit any key to stop autoboot:  0
FDT ERROR:get muxsel err returned FDT_ERR_INTERNAL
sunxi_pwm_pin_set_state, fdt_set_all_pin, ret=-1
[00.929]I80_HX8537 BL OPEN ![00.932]LCD open finish
Android's image name: d1-whycanpi0a_hx
No reserved memory region found in source FDT
[01.314]
Starting kernel ...

都是这个错误：

FDT ERROR:get muxsel err returned FDT_ERR_INTERNAL
sunxi_pwm_pin_set_state, fdt_set_all_pin, ret=-1

引脚设置复用失败？

whycan晕哥 LV 9

然后死马做活马医，改成gpio配置背光：

&lcd0 {
...
lcd_gpio_1 = <&pio PD 22 1 0 3 1>;
...
}

然后 lcd驱动里面：

static void LCD_power_on(u32 sel)
{
        sunxi_lcd_pin_cfg(sel, 1);
        sunxi_lcd_delay_ms(20);
        sunxi_lcd_gpio_set_value(sel, 1, 1);//backlight on
}

这样背光正常了。

whycan晕哥 LV 9

@whycan

u-boot 命令行读 PD_CFG2 的寄存器内容是：

=> mm 0x02000098
02000098: 0f222222

说明 PD22_SELECT 是 1111 （IO disable）

那是dts配错了，还是u-boot有 bug 呢？

whycan晕哥 LV 9

@whycan

root@TinaLinux:/# devmem 0x02000098
0x05222222

进入Linux 之后，读出 PD22_SELECT 是 0101，
刚好是 PWM 复用。

whycan晕哥 LV 9

按住 s 上电启动可以进入u-boot命令行，输入两行命令可以把PD22拉高：

mw 0x02000098 0x01222222
mw 0x020000A0 0x00400000