lkml.org 
[lkml]   [2022]   [May]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: Question about SC16IS752 device tree.
    Hi Zhou,

    Le mar., mai 10 2022 at 02:08:28 +0800, Zhou Yanjie
    <zhouyanjie@wanyeetech.com> a écrit :
    > Hi folks,
    >
    > I encountered a problem when using the SC16IS752 to expand the serial
    > port.
    > I connected two Bluetooth modules to the two serial ports extended by
    > the
    > SC16IS752. The device tree is as follows:
    >
    > &ssi0 {
    > status = "okay";
    >
    > num-cs = <2>;
    >
    > pinctrl-names = "default";
    > pinctrl-0 = <&pins_ssi0>;
    >
    > sc16is752: expander@0 {
    > compatible = "nxp,sc16is752";
    > reg = <0>; /* CE0 */
    >
    > spi-rx-bus-width = <1>;
    > spi-tx-bus-width = <1>;
    > spi-max-frequency = <6000000>;
    >
    > clocks = <&exclk_sc16is752>;
    >
    > interrupt-parent = <&gpb>;
    > interrupts = <18 IRQ_TYPE_EDGE_FALLING>;
    >
    > gpio-controller;
    > #gpio-cells = <2>;
    >
    > bluetooth@0 {
    > compatible = "brcm,bcm43438-bt";
    > max-speed = <1000000>;
    >
    > device-wakeup-gpios = <&gpc 26 GPIO_ACTIVE_HIGH>;
    > reset-gpios = <&gpb 17 GPIO_ACTIVE_LOW>;
    > };
    >
    > bluetooth@1 {
    > compatible = "brcm,bcm43438-bt";
    >
    > device-wakeup-gpios = <&gpc 28 GPIO_ACTIVE_HIGH>;
    > reset-gpios = <&gpb 19 GPIO_ACTIVE_LOW>;
    > };
    > };
    > };
    >
    >
    >
    > There are the following error messages after startup:
    >
    > [ 0.548417] serial serial0-0: controller busy
    > [ 0.553572] serial serial0-0: failure adding device. status -EBUSY
    > [ 0.559764] serial serial0: tty port ttySC0 registered
    > [ 0.565545] spi0.0: ttySC1 at I/O 0x1 (irq = 18, base_baud =
    > 3000000) is a SC16IS752
    > [ 0.573987] serial serial1-0: controller busy
    > [ 0.578351] serial serial1-0: failure adding device. status -EBUSY
    > [ 0.585003] serial serial1: tty port ttySC1 registered
    >
    > And only the module connected to the first serial port (ttySC0) can
    > work normally.

    I can't say for sure that it's your problem, but your bluetooth nodes
    are missing "reg" properties.

    Cheers,
    -Paul

    >
    >
    >
    > If I change the device tree to:
    >
    > &ssi0 {
    > status = "okay";
    >
    > num-cs = <2>;
    >
    > pinctrl-names = "default";
    > pinctrl-0 = <&pins_ssi0>;
    >
    > sc16is752: expander@0 {
    > compatible = "nxp,sc16is752";
    > reg = <0>; /* CE0 */
    >
    > spi-rx-bus-width = <1>;
    > spi-tx-bus-width = <1>;
    > spi-max-frequency = <6000000>;
    >
    > clocks = <&exclk_sc16is752>;
    >
    > interrupt-parent = <&gpb>;
    > interrupts = <18 IRQ_TYPE_EDGE_FALLING>;
    >
    > gpio-controller;
    > #gpio-cells = <2>;
    >
    > bluetooth@0 {
    > compatible = "brcm,bcm43438-bt";
    > max-speed = <1000000>;
    >
    > device-wakeup-gpios = <&gpc 26 GPIO_ACTIVE_HIGH>;
    > reset-gpios = <&gpb 17 GPIO_ACTIVE_LOW>;
    > };
    > };
    > };
    >
    > Then there will be no error message, and the module connected to the
    > first
    > serial port (ttySC0) can also work normally.
    >
    >
    >
    > After tracing, the problem seems to be in "serdev_device_add()" (line
    > 111) of
    > "drivers/tty/serdev/core.c":
    >
    > int serdev_device_add(struct serdev_device *serdev)
    > {
    > struct serdev_controller *ctrl = serdev->ctrl;
    > struct device *parent = serdev->dev.parent;
    > int err;
    >
    > dev_set_name(&serdev->dev, "%s-%d", dev_name(parent), serdev->nr);
    >
    > /* Only a single slave device is currently supported. */
    > if (ctrl->serdev) {
    > dev_err(&serdev->dev, "controller busy\n");
    > return -EBUSY;
    > }
    > ctrl->serdev = serdev;
    >
    > err = device_add(&serdev->dev);
    > if (err < 0) {
    > dev_err(&serdev->dev, "Can't add %s, status %pe\n",
    > dev_name(&serdev->dev), ERR_PTR(err));
    > goto err_clear_serdev;
    > }
    >
    > dev_dbg(&serdev->dev, "device %s registered\n",
    > dev_name(&serdev->dev));
    >
    > return 0;
    >
    > err_clear_serdev:
    > ctrl->serdev = NULL;
    > return err;
    > }
    > EXPORT_SYMBOL_GPL(serdev_device_add);
    >
    >
    >
    > Is there any way to correctly describe the device mounted on the
    > second
    > serial port (ttySC1) in the device tree? Or how do I need to modify
    > the
    > "drivers/tty/serdev/core.c" to make the SC16IS752 still work properly
    > with two child nodes mounted?
    >
    > Thanks and beset regards!


    \
     
     \ /
      Last update: 2022-05-09 20:16    [W:6.270 / U:0.556 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site