Messages in this thread | | | Date | Mon, 09 May 2022 19:13:47 +0100 | From | Paul Cercueil <> | Subject | Re: Question about SC16IS752 device tree. |
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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!
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