Hi Zhou,
Le mar., mai 10 2022 at 02:08:28 +0800, Zhou Yanjie
<zhouyanjie@xxxxxxxxxxxxxx> 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!