Re: [PATCH] MEDIATEK: serial: 8250_mtk: Add ACPI support

Re: [PATCH] MEDIATEK: serial: 8250_mtk: Add ACPI support

[Greg Kroah-Hartman]

On Fri, Nov 28, 2025 at 10:17:56AM +0800, zhiyong.tao wrote:
> From: "Zhiyong.Tao" <zhiyong.tao@mediatek.com>

Please use your name, not your email alias (i.e. drop the "." from the
name portion.)

> 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>
> ---
>  drivers/tty/serial/8250/8250_mtk.c | 23 +++++++++++++++++++----
>  1 file changed, 19 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/tty/serial/8250/8250_mtk.c b/drivers/tty/serial/8250/8250_mtk.c
> index 5875a7b9b4b1..e6a56cf54ae0 100644
> --- 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>

Do you also need to update the Kconfig dependencies?

thanks,

greg k-h

[PATCH 0/1] Mediatek uart patch

[Zhiyong Tao]

This series includes 1 patch:
Add ACPI support on 8250_mtk driver

Zhiyong.Tao (1):
  MEDIATEK: serial: 8250_mtk: Add ACPI support

 drivers/tty/serial/8250/8250_mtk.c | 22 ++++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

--
2.45.2

[PATCH] MEDIATEK: serial: 8250_mtk: Add ACPI support

[Zhiyong Tao]

From: "Zhiyong.Tao" <zhiyong.tao@mediatek.com>

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>
---
 drivers/tty/serial/8250/8250_mtk.c | 23 +++++++++++++++++++----
 1 file changed, 19 insertions(+), 4 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_mtk.c b/drivers/tty/serial/8250/8250_mtk.c
index 5875a7b9b4b1..e6a56cf54ae0 100644
--- 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,
-- 
2.45.2

Re: [PATCH] MEDIATEK: serial: 8250_mtk: Add ACPI support

[Greg KH]

On Mon, Jan 05, 2026 at 10:39:55AM +0800, Zhiyong Tao wrote:
> From: "Zhiyong.Tao" <zhiyong.tao@mediatek.com>
> 
> 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>
> ---
>  drivers/tty/serial/8250/8250_mtk.c | 23 +++++++++++++++++++----
>  1 file changed, 19 insertions(+), 4 deletions(-)

This is a resend of the previous version, right?  Or did something
change?

confused,

greg k-h

Re: [PATCH] MEDIATEK: serial: 8250_mtk: Add ACPI support

[Zhiyong Tao (陶志勇)]

On Tue, 2026-01-06 at 11:02 +0100, Greg KH wrote:
> On Mon, Jan 05, 2026 at 10:39:55AM +0800, Zhiyong Tao wrote:
> > From: "Zhiyong.Tao" <zhiyong.tao@mediatek.com>
> > 
> > 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>
> > ---
> >  drivers/tty/serial/8250/8250_mtk.c | 23 +++++++++++++++++++----
> >  1 file changed, 19 insertions(+), 4 deletions(-)
> 
> This is a resend of the previous version, right?  Or did something
> change?
> 
> confused,
> 
> greg k-h

==> Hi Greg,
Yes, previously Yenchia Chen helped to send out a version. Currently,
this solution is specifically for the GB10 project and was made to
support Windows ACPI settings. 

In actual application scenarios, the apdma clk will not be turned off
in normal mode. It is only turned off in the SSPM microprocessor after
entering standby, and when resuming, the apdma clk is re-enabled by
SSPM.

As for other Linux projects, apdma still uses the DTS node.

Thanks

Re: [PATCH] MEDIATEK: serial: 8250_mtk: Add ACPI support

[Zhiyong Tao (陶志勇)]

On Wed, 2026-01-21 at 14:23 +0800, Zhiyong Tao wrote:
> On Tue, 2026-01-06 at 11:02 +0100, Greg KH wrote:
> > On Mon, Jan 05, 2026 at 10:39:55AM +0800, Zhiyong Tao wrote:
> > > From: "Zhiyong.Tao" <zhiyong.tao@mediatek.com>
> > > 
> > > 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>
> > > ---
> > >  drivers/tty/serial/8250/8250_mtk.c | 23 +++++++++++++++++++----
> > >  1 file changed, 19 insertions(+), 4 deletions(-)
> > 
> > This is a resend of the previous version, right?  Or did something
> > change?
> > 
> > confused,
> > 
> > greg k-h
> 
> ==> Hi Greg,
> Yes, previously Yenchia Chen helped to send out a version. Currently,
> this solution is specifically for the GB10 project and was made to
> support Windows ACPI settings. 
> 
> In actual application scenarios, the apdma clk will not be turned off
> in normal mode. It is only turned off in the SSPM microprocessor
> after
> entering standby, and when resuming, the apdma clk is re-enabled by
> SSPM.
> 
> As for other Linux projects, apdma still uses the DTS node.
> 
> Thanks
> 

Hi Greg,
Do you have other suggestion for this?

Thanks

Re: [PATCH] MEDIATEK: serial: 8250_mtk: Add ACPI support

[gregkh]

On Wed, Mar 18, 2026 at 12:12:36PM +0000, Zhiyong Tao (陶志勇) wrote:
> On Wed, 2026-01-21 at 14:23 +0800, Zhiyong Tao wrote:
> > On Tue, 2026-01-06 at 11:02 +0100, Greg KH wrote:
> > > On Mon, Jan 05, 2026 at 10:39:55AM +0800, Zhiyong Tao wrote:
> > > > From: "Zhiyong.Tao" <zhiyong.tao@mediatek.com>
> > > > 
> > > > 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>
> > > > ---
> > > >  drivers/tty/serial/8250/8250_mtk.c | 23 +++++++++++++++++++----
> > > >  1 file changed, 19 insertions(+), 4 deletions(-)
> > > 
> > > This is a resend of the previous version, right?  Or did something
> > > change?
> > > 
> > > confused,
> > > 
> > > greg k-h
> > 
> > ==> Hi Greg,
> > Yes, previously Yenchia Chen helped to send out a version. Currently,
> > this solution is specifically for the GB10 project and was made to
> > support Windows ACPI settings. 
> > 
> > In actual application scenarios, the apdma clk will not be turned off
> > in normal mode. It is only turned off in the SSPM microprocessor
> > after
> > entering standby, and when resuming, the apdma clk is re-enabled by
> > SSPM.
> > 
> > As for other Linux projects, apdma still uses the DTS node.
> > 
> > Thanks
> > 
> 
> Hi Greg,
> Do you have other suggestion for this?

You can't just resend something and not say why you are resending it.
Also, the authorship information seems to be backwards.

thanks,

greg k-h

Re: [PATCH] MEDIATEK: serial: 8250_mtk: Add ACPI support

[Zhiyong Tao (陶志勇)]

On Wed, 2026-03-18 at 15:19 +0100, gregkh@linuxfoundation.org wrote:
> On Wed, Mar 18, 2026 at 12:12:36PM +0000, Zhiyong Tao (陶志勇) wrote:
> > On Wed, 2026-01-21 at 14:23 +0800, Zhiyong Tao wrote:
> > > On Tue, 2026-01-06 at 11:02 +0100, Greg KH wrote:
> > > > On Mon, Jan 05, 2026 at 10:39:55AM +0800, Zhiyong Tao wrote:
> > > > > From: "Zhiyong.Tao" <zhiyong.tao@mediatek.com>
> > > > > 
> > > > > 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>
> > > > > ---
> > > > >  drivers/tty/serial/8250/8250_mtk.c | 23 +++++++++++++++++++-
> > > > > ---
> > > > >  1 file changed, 19 insertions(+), 4 deletions(-)

==>Hi Greg,

Yes, it is a resend of the previous version to rebase to tip for
friendly ping. it is based on the latest linux-next version.

Thanks

> > > > 
> > > > This is a resend of the previous version, right?  Or did
> > > > something
> > > > change?
> > > > 
> > > > confused,
> > > > 
> > > > greg k-h
> > > 
> > > ==> Hi Greg,
> > > Yes, previously Yenchia Chen helped to send out a version.
> > > Currently,
> > > this solution is specifically for the GB10 project and was made
> > > to
> > > support Windows ACPI settings. 
> > > 
> > > In actual application scenarios, the apdma clk will not be turned
> > > off
> > > in normal mode. It is only turned off in the SSPM microprocessor
> > > after
> > > entering standby, and when resuming, the apdma clk is re-enabled
> > > by
> > > SSPM.
> > > 
> > > As for other Linux projects, apdma still uses the DTS node.
> > > 
> > > Thanks
> > > 
> > 
> > Hi Greg,
> > Do you have other suggestion for this?
> 
> You can't just resend something and not say why you are resending it.
> Also, the authorship information seems to be backwards.
> 
> thanks,
> 
> greg k-h

Re: [PATCH] MEDIATEK: serial: 8250_mtk: Add ACPI support

[Greg KH]

On Mon, Jan 05, 2026 at 10:39:55AM +0800, Zhiyong Tao wrote:
> From: "Zhiyong.Tao" <zhiyong.tao@mediatek.com>
> 
> 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>

Please use your name, not '.' in it, like your email has.  Yenchia did
it properly here.

thanks,

greg k-h

Re: [PATCH] MEDIATEK: serial: 8250_mtk: Add ACPI support

[Zhiyong Tao (陶志勇)]

On Fri, 2026-01-16 at 14:20 +0100, Greg KH wrote:
> On Mon, Jan 05, 2026 at 10:39:55AM +0800, Zhiyong Tao wrote:
> > From: "Zhiyong.Tao" <zhiyong.tao@mediatek.com>
> > 
> > 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>
> 
> Please use your name, not '.' in it, like your email has.  Yenchia
> did
> it properly here.
> 
> thanks,
> 
> greg k-h
> 
> ==> Thank you for your suggestion. I will fix this change in the next
> version. 

[PATCH v2 0/1] Mediatek uart patch

[Zhiyong Tao]

This series includes 1 patch:
Add ACPI support on 8250_mtk driver

Changes in patch v2:
1)Change pacth name from 'zhiyong.tao<zhiyong.tao@mediatek.com>'
  to 'Zhiyong Tao <zhiyong.tao@mediatek.com>'.
2)Resend the UART upstream patch based on the latest Linux
  kernel version(from 'tag: next-20251118' to 'tag: next-20260417').

There is no code change compare to v1.

Zhiyong Tao (1):
  MEDIATEK: serial: 8250_mtk: Add ACPI support

 drivers/tty/serial/8250/8250_mtk.c | 23 +++++++++++++++++++----
 1 file changed, 19 insertions(+), 4 deletions(-)

--
2.45.2

[PATCH] MEDIATEK: serial: 8250_mtk: Add ACPI support

[Zhiyong Tao]

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>
---
 drivers/tty/serial/8250/8250_mtk.c | 23 +++++++++++++++++++----
 1 file changed, 19 insertions(+), 4 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_mtk.c b/drivers/tty/serial/8250/8250_mtk.c
index 5875a7b9b4b10..e6a56cf54ae0c 100644
--- 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,
-- 
2.45.2