serial: 8250_mtk: Add ACPI support

Add ACPI support to 8250_mtk driver. This makes it possible to
use UART on ARM-based desktops with EDK2 UEFI firmware.

Signed-off-by: Yenchia Chen <yenchia.chen@mediatek.com>
Signed-off-by: Zhiyong Tao <zhiyong.tao@mediatek.com>
Link: https://patch.msgid.link/20260423062345.2473300-2-zhiyong.tao@mediatek.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/8250/8250_mtk.c b/drivers/tty/serial/8250/8250_mtk.c
index 5875a7b9b4b100f15bd4b3434cd30839a48c1e04..e6a56cf54ae0c1fe8664fc08e9059bc1559f2728 100644 (file)
--- a/drivers/tty/serial/8250/8250_mtk.c
+++ b/drivers/tty/serial/8250/8250_mtk.c
@@ -19,6 +19,7 @@
 #include <linux/dma-mapping.h>
 #include <linux/tty.h>
 #include <linux/tty_flip.h>
+#include <linux/units.h>
 
 #include "8250.h"
 
@@ -521,6 +522,7 @@ static int mtk8250_probe(struct platform_device *pdev)
        struct mtk8250_data *data;
        struct resource *regs;
        int irq, err;
+       struct fwnode_handle *fwnode = dev_fwnode(&pdev->dev);
 
        irq = platform_get_irq(pdev, 0);
        if (irq < 0)
@@ -543,12 +545,13 @@ static int mtk8250_probe(struct platform_device *pdev)
 
        data->clk_count = 0;
 
-       if (pdev->dev.of_node) {
+       if (is_of_node(fwnode)) {
                err = mtk8250_probe_of(pdev, &uart.port, data);
                if (err)
                        return err;
-       } else
+       } else if (!fwnode) {
                return -ENODEV;
+       }
 
        spin_lock_init(&uart.port.lock);
        uart.port.mapbase = regs->start;
@@ -564,14 +567,18 @@ static int mtk8250_probe(struct platform_device *pdev)
        uart.port.startup = mtk8250_startup;
        uart.port.set_termios = mtk8250_set_termios;
        uart.port.uartclk = clk_get_rate(data->uart_clk);
+       if (!uart.port.uartclk)
+               uart.port.uartclk = 26 * HZ_PER_MHZ;
 #ifdef CONFIG_SERIAL_8250_DMA
        if (data->dma)
                uart.dma = data->dma;
 #endif
 
-       /* Disable Rate Fix function */
-       writel(0x0, uart.port.membase +
+       if (is_of_node(fwnode)) {
+               /* Disable Rate Fix function */
+               writel(0x0, uart.port.membase +
                        (MTK_UART_RATE_FIX << uart.port.regshift));
+       }
 
        platform_set_drvdata(pdev, data);
 
@@ -649,11 +656,19 @@ static const struct of_device_id mtk8250_of_match[] = {
 };
 MODULE_DEVICE_TABLE(of, mtk8250_of_match);
 
+static const struct acpi_device_id mtk8250_acpi_match[] = {
+       { "MTKI0511" },
+       { "NVDA0240" },
+       {}
+};
+MODULE_DEVICE_TABLE(acpi, mtk8250_acpi_match);
+
 static struct platform_driver mtk8250_platform_driver = {
        .driver = {
                .name           = "mt6577-uart",
                .pm             = &mtk8250_pm_ops,
                .of_match_table = mtk8250_of_match,
+               .acpi_match_table = mtk8250_acpi_match,
        },
        .probe                  = mtk8250_probe,
        .remove                 = mtk8250_remove,