Mon, Jul 05, 2021 at 09:00:10PM +0800, Huacai Chen kirjoitti:

From: Jianmin Lv <lvjianmin@loongson.cn>

ACPI-based Loongson boards need configurable rather than fixed clock
frequency for serial ports.

...

 #include <linux/kernel.h>
 #include <linux/serial_core.h>
 #include <linux/bitops.h>
+#include <linux/property.h>

Can you try to keep it ordered (to some extend), please?

...

 	uart.port.flags |= UPF_SKIP_TEST | UPF_BOOT_AUTOCONF;
 	if (pnp_irq_flags(dev, 0) & IORESOURCE_IRQ_SHAREABLE)
 		uart.port.flags |= UPF_SHARE_IRQ;
-	uart.port.uartclk = 1843200;
+	if (device_property_read_u32(&dev->dev, "clock-frequency", &uart.port.uartclk))
+		uart.port.uartclk = 1843200;
 	uart.port.dev = &dev->dev;

You can avoid conditional completely by calling 

	device_property_read_u32(&dev->dev, "clock-frequency", &uart.port.uartclk);

here.

-- 
With Best Regards,
Andy Shevchenko