摘要：
当usbit被拉起时，开发板被用作外围设备。当然，除了使用硬件模式外，您还可以直接通过Linux系统更改当前的USB模式。具体示意图如下：2。完成设备树和驱动程序代码配置的硬件处理，然后修改软件。打开Linux 5.7.1内核源代码2.1。首先，修改设备树文件arch/arm/boot/dts/suniv-f1c100s.dtsi，以在soc节点_ otg下添加usb：usb@1c13000｛compatible=“allwinner，suniv musb”；reg=；时钟=；重置=；中断=；中断名称=“mc”；phys=；phy名称=“usb”；extcon=；allwinner；sram=；状态=“禁用”；｝；美国药典：phy@1c13400｛compatible=“allwinner，suniv usb-phy”；reg=；reg names=“phy_ctrl”；clocks=；clock names=“usb0_phy”；reset=；reset names=“usb0_reset”；#phy cells=；status=“disabled”；｝；2.2修改arch/arm/boot/dts/suniv-f1c100s-lichepi-nano.dts文件，并将&otg添加到文件_ sram｛status=“ok”；｝；&usb_ Otg｛dr_mode=“host”；/*三个选项：Otg/主机/外围设备我在这里指定为主机模式*/status=“ok”；｝&usbphy｛usb0_id_det-gpio=；/*PE2*/status=“OK”；}；2.3修改驱动程序/phy/allwinder/phy sun4i usb。c文件，因为我们在设备树中定义的驱动程序是sunivusbphy，所以我们需要添加这部分代码。
本文章基于
https://whycan.com/t_3087.html
https://whycan.com/t_6021.html
整理
F1c100s芯片支持USB的OTG模式，也就是可以通过更改UsbId拉低或拉高方式定义当前的开发板可以作为host还是device。
- usbid 拉高时，开发板作为外设方式。
- usbid 拉低时，开发板作为主机方式。
当然除了使用硬件方式，还可以通过Linux系统直接更改当前USB的模式。
1. 原理图
在F1c100s中PE2引脚是作为usbid功能来使用，因为为了使用Sunxi-tool 所以我在画原理图的时候默认将PE2做了上拉处理。
这个芯片只有一个usb引脚
为了可以引出更多的usb外设，所以这里使用了FE8.1这个USB Hub芯片，这个芯片最多可以引出4个Usb接口。具体原理图如下：
2. 设备树与驱动代码配置
硬件处理完成，接下来就是软件部分修改了，打开Linux5.7.1内核源码
2.1 首先修改设备树文件arch/arm/boot/dts/suniv-f1c100s.dtsi文件
在soc节点下增加
usb_otg: usb@1c13000 { compatible = "allwinner,suniv-musb"; reg = <0x01c13000 0x0400>; clocks = <&ccu CLK_BUS_OTG>; resets = <&ccu RST_BUS_OTG>; interrupts = <26>; interrupt-names = "mc"; phys = <&usbphy 0>; phy-names = "usb"; extcon = <&usbphy 0>; allwinner,sram = <&otg_sram 1>; status = "disabled"; }; usbphy: phy@1c13400 { compatible = "allwinner,suniv-usb-phy"; reg = <0x01c13400 0x10>; reg-names = "phy_ctrl"; clocks = <&ccu CLK_USB_PHY0>; clock-names = "usb0_phy"; resets = <&ccu RST_USB_PHY0>; reset-names = "usb0_reset"; #phy-cells = <1>; status = "disabled"; };
2.2 修改arch/arm/boot/dts/suniv-f1c100s-licheepi-nano.dts文件
在文件里面添加
&otg_sram { status = "okay"; }; &usb_otg { dr_mode = "host"; /* 三个可选项: otg / host / peripheral 我在这里指定为host模式*/ status = "okay"; }; &usbphy { usb0_id_det-gpio = <&pio 4 2 GPIO_ACTIVE_HIGH>; /* PE2 */ status = "okay"; };
2.3 修改drivers/phy/allwinner/phy-sun4i-usb.c文件
因为我们在设备树中定义的驱动是suniv-usb-phy，所以我们需要添加这部分代码。
enum sun4i_usb_phy_type { suniv_phy, //新增枚举值 sun4i_a10_phy, sun6i_a31_phy, sun8i_a33_phy, sun8i_a83t_phy, sun8i_h3_phy, sun8i_r40_phy, sun8i_v3s_phy, sun50i_a64_phy, sun50i_h6_phy, };
//新增以下结构 static const struct sun4i_usb_phy_cfg suniv_cfg = { .num_phys = 1, .type = suniv_phy, .disc_thresh = 3, .phyctl_offset = REG_PHYCTL_A10, .dedicated_clocks = true, };
static const struct of_device_id sun4i_usb_phy_of_match[] = { { .compatible = "allwinner,suniv-usb-phy", .data = &suniv_cfg }, //新增配置项 { .compatible = "allwinner,sun4i-a10-usb-phy", .data = &sun4i_a10_cfg }, { .compatible = "allwinner,sun5i-a13-usb-phy", .data = &sun5i_a13_cfg }, { .compatible = "allwinner,sun6i-a31-usb-phy", .data = &sun6i_a31_cfg }, { .compatible = "allwinner,sun7i-a20-usb-phy", .data = &sun7i_a20_cfg }, { .compatible = "allwinner,sun8i-a23-usb-phy", .data = &sun8i_a23_cfg }, { .compatible = "allwinner,sun8i-a33-usb-phy", .data = &sun8i_a33_cfg }, { .compatible = "allwinner,sun8i-a83t-usb-phy", .data = &sun8i_a83t_cfg }, { .compatible = "allwinner,sun8i-h3-usb-phy", .data = &sun8i_h3_cfg }, { .compatible = "allwinner,sun8i-r40-usb-phy", .data = &sun8i_r40_cfg }, { .compatible = "allwinner,sun8i-v3s-usb-phy", .data = &sun8i_v3s_cfg }, { .compatible = "allwinner,sun50i-a64-usb-phy", .data = &sun50i_a64_cfg}, { .compatible = "allwinner,sun50i-h6-usb-phy", .data = &sun50i_h6_cfg }, { }, };
2.4 修改drivers/usb/musb/sunxi.c文件
这里主要处理设备树中定义的驱动suniv-musb。
static int sunxi_musb_probe(struct platform_device *pdev) { struct musb_hdrc_platform_data pdata; struct platform_device_info pinfo; struct sunxi_glue *glue; struct device_node *np = pdev->dev.of_node; int ret; if (!np) { dev_err(&pdev->dev, "Error no device tree node found "); return -EINVAL; } glue = devm_kzalloc(&pdev->dev, sizeof(*glue), GFP_KERNEL); if (!glue) return -ENOMEM; memset(&pdata, 0, sizeof(pdata)); switch (usb_get_dr_mode(&pdev->dev)) { #if defined CONFIG_USB_MUSB_DUAL_ROLE || defined CONFIG_USB_MUSB_HOST case USB_DR_MODE_HOST: pdata.mode = MUSB_HOST; glue->phy_mode = PHY_MODE_USB_HOST; break; #endif #if defined CONFIG_USB_MUSB_DUAL_ROLE || defined CONFIG_USB_MUSB_GADGET case USB_DR_MODE_PERIPHERAL: pdata.mode = MUSB_PERIPHERAL; glue->phy_mode = PHY_MODE_USB_DEVICE; break; #endif #ifdef CONFIG_USB_MUSB_DUAL_ROLE case USB_DR_MODE_OTG: pdata.mode = MUSB_OTG; glue->phy_mode = PHY_MODE_USB_OTG; break; #endif default: dev_err(&pdev->dev, "Invalid or missing 'dr_mode' property "); return -EINVAL; } pdata.platform_ops = &sunxi_musb_ops; if (!of_device_is_compatible(np, "allwinner,sun8i-h3-musb")) pdata.config = &sunxi_musb_hdrc_config; else pdata.config = &sunxi_musb_hdrc_config_h3; glue->dev = &pdev->dev; INIT_WORK(&glue->work, sunxi_musb_work); glue->host_nb.notifier_call = sunxi_musb_host_notifier; if (of_device_is_compatible(np, "allwinner,sun4i-a10-musb")|| of_device_is_compatible(np, "allwinner,suniv-musb")){ //新增判断项代码 set_bit(SUNXI_MUSB_FL_HAS_SRAM, &glue->flags); } if (of_device_is_compatible(np, "allwinner,sun6i-a31-musb")) set_bit(SUNXI_MUSB_FL_HAS_RESET, &glue->flags); if (of_device_is_compatible(np, "allwinner,sun8i-a33-musb") || of_device_is_compatible(np, "allwinner,sun8i-h3-musb") || of_device_is_compatible(np, "allwinner,suniv-musb")) { //新增判断项代码 set_bit(SUNXI_MUSB_FL_HAS_RESET, &glue->flags); set_bit(SUNXI_MUSB_FL_NO_CONFIGDATA, &glue->flags); } glue->clk = devm_clk_get(&pdev->dev, NULL); if (IS_ERR(glue->clk)) { dev_err(&pdev->dev, "Error getting clock: %ld ", PTR_ERR(glue->clk)); return PTR_ERR(glue->clk); } if (test_bit(SUNXI_MUSB_FL_HAS_RESET, &glue->flags)) { glue->rst = devm_reset_control_get(&pdev->dev, NULL); if (IS_ERR(glue->rst)) { if (PTR_ERR(glue->rst) == -EPROBE_DEFER) return -EPROBE_DEFER; dev_err(&pdev->dev, "Error getting reset %ld ", PTR_ERR(glue->rst)); return PTR_ERR(glue->rst); } } …………
static const struct of_device_id sunxi_musb_match[] = { { .compatible = "allwinner,suniv-musb", }, //新增代码 { .compatible = "allwinner,sun4i-a10-musb", }, { .compatible = "allwinner,sun6i-a31-musb", }, { .compatible = "allwinner,sun8i-a33-musb", }, { .compatible = "allwinner,sun8i-h3-musb", }, {} };
2.5 通过menuconfig配置usb相关的选项
进入：Device Drivers - USB support
进行配置，当然可以根据自己实际情况进行开启与配置。
接下载编译Linux编译内核和设备树，就可以得到内核文件和设备树文件了。
3. 测试USB键盘
这里我默认设置开发板为host模式，然后我要通过usb连接键盘进行输入操作：
[ 31.653231] cfg80211: failed to load regulatory.db [ 31.696053] EXT4-fs (mmcblk0p2): mounted filesystem with ordered data mode. Opts: (null) [ 31.707915] VFS: Mounted root (ext4 filesystem) on device 179:2. [ 31.726584] devtmpfs: mounted [ 31.736031] Freeing unused kernel memory: 1024K [ 31.746083] Run /sbin/init as init process [ 32.023410] usb 1-1: new high-speed USB device number 2 using musb-hdrc [ 32.215728] hub 1-1:1.0: USB hub found [ 32.221496] hub 1-1:1.0: 4 ports detected
启动日志中我们可以看到usb已经被检测到，并且检测到4个端口，但是我们只用到两个。
插入键盘。
拔出键盘。
键盘操作开发板：
如果想要进一步了解usb相关的操作，可以借助usbutils相关组件。
首先安装usbutils组件
apt-get install usbutils安装完成后执行：
lsusb
就可以查看相关usb设备信息了。
4 通过LINUX方式更改USB属性
首先更改设备树，改为otg模式
&usb_otg { dr_mode = "otg"; /* 三个可选项: otg / host / peripheral */ status = "okay"; };
进入Linux系统,执行,usb将会被设置成为host模式
echo host > /sys/devices/platform/soc/1c13000.usb/musb-hdrc.1.auto/mode
运行结果如下，此时可以插入键盘，就可以使用键盘操作Linux了。
# echo host > /sys/devices/platform/soc/1c13000.usb/musb-hdrc.1.auto/mode # [117.758152] phy phy-1c13400.phy.0: Changing dr_mode to 1 [ 118.414817] usb 1-1: new high-speed USB device number 3 using musb-hdrc [ 118.598193] usb-storage 1-1:1.0: USB Mass Storage device detected [ 118.611789] scsi host0: usb-storage 1-1:1.0 [ 119.686198] scsi 0:0:0:0: Direct-Access Mass Storage Device 1.00 PQ: 0 ANSI: 0 CCS [ 119.703976] sd 0:0:0:0: [sda] 3842048 512-byte logical blocks: (1.97 GB/1.83 GiB) [ 119.725260] sd 0:0:0:0: Attached scsi generic sg0 type 0 [ 119.739844] sd 0:0:0:0: [sda] Write Protect is off [ 119.771819] sd 0:0:0:0: [sda] No Caching mode page found [ 119.777288] sd 0:0:0:0: [sda] Assuming drive cache: write through [ 119.801571] sda: sda1 sda2 sda3 [ 119.817224] sd 0:0:0:0: [sda] Attached SCSI removable disk
如果执行如下命令，则进入设备模式
# ##切换到device模式: # echo peripheral > /sys/devices/platform/soc/1c13000.usb/musb-hdrc.1.auto/mode [ 123.880272] phy phy-1c13400.phy.0: Changing dr_mode to 2 # [ 123.890905] usb 1-1: USB disconnect, device number 3
后记
在论坛中用有测试表明，在这个方案配置完USB后，可能无法同时运行两个控制设备，墨云没做相关测试，如果有相关需求的还请注意核实。谢谢