i.mx6ull 移植串口3，串口4 不通，@左神小哥哥

casy99 · 发表于 2020-3-5 15:30:19

照葫芦画瓢哦，嘿嘿!修改alientek_emmc.dts文件：

重点第一部分：

&uart1 {
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_uart1>;
status = "okay";
};

/* infer the ttymxc2 */
&uart3 {
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_uart3>;
status = "okay";
};

/* infer the ttymxc3 */
&uart4 {
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_uart4>;
status = "okay";
};

/* infer the ttymxc4 */
&uart5 {
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_uart5>;
status = "okay";
};

重点第二处：

pinctrl_uart1: uart1grp {
fsl,pins = <
MX6UL_PAD_UART1_TX_DATA__UART1_DCE_TX 0x1b0b1
MX6UL_PAD_UART1_RX_DATA__UART1_DCE_RX 0x1b0b1
>;
};

pinctrl_uart2: uart2grp {
fsl,pins = <
/* MX6UL_PAD_UART2_TX_DATA__UART2_DCE_TX 0x1b0b1 */
/* MX6UL_PAD_UART2_RX_DATA__UART2_DCE_RX 0x1b0b1 */
/*MX6UL_PAD_UART3_RX_DATA__UART2_DCE_RTS 0x1b0b1 */
/*MX6UL_PAD_UART3_TX_DATA__UART2_DCE_CTS 0x1b0b1 */
>;
};

pinctrl_uart2dte: uart2dtegrp {
fsl,pins = <
/* MX6UL_PAD_UART2_TX_DATA__UART2_DTE_RX 0x1b0b1 */
/* MX6UL_PAD_UART2_RX_DATA__UART2_DTE_TX 0x1b0b1 */
/* MX6UL_PAD_UART3_RX_DATA__UART2_DTE_CTS 0x1b0b1 */
/* MX6UL_PAD_UART3_TX_DATA__UART2_DTE_RTS 0x1b0b1 */
>;
};

/* zuozhongkai */
pinctrl_uart3: uart3grp {
fsl,pins = <
MX6UL_PAD_UART3_TX_DATA__UART3_DCE_TX 0X1b0b1
MX6UL_PAD_UART3_RX_DATA__UART3_DCE_RX 0X1b0b1
>;
};

      /* add by casy */
pinctrl_uart4: uart4grp {
fsl,pins = <
MX6UL_PAD_UART4_TX_DATA__UART4_DCE_TX 0X1b0b1
MX6UL_PAD_UART4_RX_DATA__UART4_DCE_RX 0X1b0b1
>;
};

pinctrl_uart5: uart5grp {
fsl,pins = <
   MX6UL_PAD_UART5_RX_DATA__UART5_DCE_RX    0x1b0b1
   MX6UL_PAD_UART5_TX_DATA__UART5_DCE_TX    0x1b0b1
>;
};

casy99 · 发表于 2020-3-5 15:33:55

进去后，奇迹出现了！无标题.jpg

casy99 · 发表于 2020-3-5 15:34:42

说明设备树起了作用，平台总线驱动和设备已经匹配了！Good

casy99 · 发表于 2020-3-5 15:36:31

接下来测试很失望；uart4 只能接受，不能发送； uart5 不能发不能收
但是uart2 一切正常
环境：左神牌linux开发板
测试方法：
查看串口接收数据：
cat /dev/ttymxc2

16进制查看串口接收数据：

hexdump -C /dev/ttymxc2
向串口发数据：
echo "test" > /dev/ttymxc2

casy99 · 发表于 2020-3-5 15:51:00

分析打印：

imx-sdma 20ec000.sdma: loaded firmware 3.3
imx-sdma 20ec000.sdma: initialized
2020000.serial: ttymxc0 at MMIO 0x2020000 (irq = 19, base_baud = 5000000) is a IMX
console [ttymxc0] enabled
21ec000.serial: ttymxc2 at MMIO 0x21ec000 (irq = 236, base_baud = 5000000) is a IMX
imx6ul-pinctrl 20e0000.iomuxc: pin MX6UL_PAD_UART4_TX_DATA already requested by 21a0000.i2c; cannot claim for 21f0000.serial
imx6ul-pinctrl 20e0000.iomuxc: pin-45 (21f0000.serial) status -22
imx6ul-pinctrl 20e0000.iomuxc: could not request pin 45 (MX6UL_PAD_UART4_TX_DATA) from group uart4grp on device 20e0000.iomuxc
imx-uart 21f0000.serial: Error applying setting, reverse things back
21f0000.serial: ttymxc3 at MMIO 0x21f0000 (irq = 237, base_baud = 5000000) is a IMX
imx6ul-pinctrl 20e0000.iomuxc: pin MX6UL_PAD_UART5_RX_DATA already requested by 21a4000.i2c; cannot claim for 21f4000.serial
imx6ul-pinctrl 20e0000.iomuxc: pin-48 (21f4000.serial) status -22
imx6ul-pinctrl 20e0000.iomuxc: could not request pin 48 (MX6UL_PAD_UART5_RX_DATA) from group uart5grp on device 20e0000.iomuxc
imx-uart 21f4000.serial: Error applying setting, reverse things back
21f4000.serial: ttymxc4 at MMIO 0x21f4000 (irq = 238, base_baud = 5000000) is a IMX
imx-rng 2284000.rngb: iMX RNG Registered.
imx sema4 driver is registered.

复制代码

casy99 · 发表于 2020-3-5 15:52:16

@左盟主，期待回复~

jiangfan111 · 发表于 2020-3-5 16:17:57

看一看设备树文件管脚有没有被其他的占用，我之前用过教程的串口和I2C连接的那俩串口都是好的啊。

casy99 · 发表于 2020-3-5 17:40:22

2020000.serial: ttymxc0 at MMIO 0x2020000 (irq = 19, base_baud = 5000000) is a IMX
console [ttymxc0] enabled
21ec000.serial: ttymxc2 at MMIO 0x21ec000 (irq = 235, base_baud = 5000000) is a IMX
21f0000.serial: ttymxc3 at MMIO 0x21f0000 (irq = 236, base_baud = 5000000) is a IMX
imx-rng 2284000.rngb: iMX RNG Registered.