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[PATCH v2 2/2] serial: 8250_dw: Add Sophgo SG2044 quirk

Inochi Amaoto posted 2 patches 1 month ago
There is a newer version of this series
[PATCH v2 2/2] serial: 8250_dw: Add Sophgo SG2044 quirk
Posted by Inochi Amaoto 1 month ago 
SG2044 relys on an internal divisor when calculating bitrate, which
means a wrong clock for the most common bitrates. So add a quirk for
this uart device to skip the set rate call and only relys on the
internal UART divisor.

Signed-off-by: Inochi Amaoto <inochiama@gmail.com>
---
 drivers/tty/serial/8250/8250_dw.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c
index ab9e7f204260..51894c93c8a3 100644
--- a/drivers/tty/serial/8250/8250_dw.c
+++ b/drivers/tty/serial/8250/8250_dw.c
@@ -750,7 +750,7 @@ static const struct dw8250_platform_data dw8250_renesas_rzn1_data = {
 	.quirks = DW_UART_QUIRK_CPR_VALUE | DW_UART_QUIRK_IS_DMA_FC,
 };
 
-static const struct dw8250_platform_data dw8250_starfive_jh7100_data = {
+static const struct dw8250_platform_data dw8250_skip_set_rate_data = {
 	.usr_reg = DW_UART_USR,
 	.quirks = DW_UART_QUIRK_SKIP_SET_RATE,
 };
@@ -760,7 +760,8 @@ static const struct of_device_id dw8250_of_match[] = {
 	{ .compatible = "cavium,octeon-3860-uart", .data = &dw8250_octeon_3860_data },
 	{ .compatible = "marvell,armada-38x-uart", .data = &dw8250_armada_38x_data },
 	{ .compatible = "renesas,rzn1-uart", .data = &dw8250_renesas_rzn1_data },
-	{ .compatible = "starfive,jh7100-uart", .data = &dw8250_starfive_jh7100_data },
+	{ .compatible = "sophgo,sg2044-uart", .data = &dw8250_skip_set_rate_data },
+	{ .compatible = "starfive,jh7100-uart", .data = &dw8250_skip_set_rate_data },
 	{ /* Sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, dw8250_of_match);
-- 
2.47.0
Re: [PATCH v2 2/2] serial: 8250_dw: Add Sophgo SG2044 quirk
Posted by Ilpo Järvinen 1 month ago 
On Mon, 21 Oct 2024, Inochi Amaoto wrote:

> SG2044 relys on an internal divisor when calculating bitrate, which
> means a wrong clock for the most common bitrates. So add a quirk for
> this uart device to skip the set rate call and only relys on the
> internal UART divisor.
> 
> Signed-off-by: Inochi Amaoto <inochiama@gmail.com>

Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

I wonder though does this mean the numbers userspace can read from kernel 
are bogus and if something can be done about that?

-- 
 i.

> ---
>  drivers/tty/serial/8250/8250_dw.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c
> index ab9e7f204260..51894c93c8a3 100644
> --- a/drivers/tty/serial/8250/8250_dw.c
> +++ b/drivers/tty/serial/8250/8250_dw.c
> @@ -750,7 +750,7 @@ static const struct dw8250_platform_data dw8250_renesas_rzn1_data = {
>  	.quirks = DW_UART_QUIRK_CPR_VALUE | DW_UART_QUIRK_IS_DMA_FC,
>  };
>  
> -static const struct dw8250_platform_data dw8250_starfive_jh7100_data = {
> +static const struct dw8250_platform_data dw8250_skip_set_rate_data = {
>  	.usr_reg = DW_UART_USR,
>  	.quirks = DW_UART_QUIRK_SKIP_SET_RATE,
>  };
> @@ -760,7 +760,8 @@ static const struct of_device_id dw8250_of_match[] = {
>  	{ .compatible = "cavium,octeon-3860-uart", .data = &dw8250_octeon_3860_data },
>  	{ .compatible = "marvell,armada-38x-uart", .data = &dw8250_armada_38x_data },
>  	{ .compatible = "renesas,rzn1-uart", .data = &dw8250_renesas_rzn1_data },
> -	{ .compatible = "starfive,jh7100-uart", .data = &dw8250_starfive_jh7100_data },
> +	{ .compatible = "sophgo,sg2044-uart", .data = &dw8250_skip_set_rate_data },
> +	{ .compatible = "starfive,jh7100-uart", .data = &dw8250_skip_set_rate_data },
>  	{ /* Sentinel */ }
>  };
>  MODULE_DEVICE_TABLE(of, dw8250_of_match);
>
Re: [PATCH v2 2/2] serial: 8250_dw: Add Sophgo SG2044 quirk
Posted by Inochi Amaoto 1 month ago 
On Mon, Oct 21, 2024 at 11:52:38AM +0300, Ilpo Järvinen wrote:
> On Mon, 21 Oct 2024, Inochi Amaoto wrote:
> 
> > SG2044 relys on an internal divisor when calculating bitrate, which
> > means a wrong clock for the most common bitrates. So add a quirk for
> > this uart device to skip the set rate call and only relys on the
> > internal UART divisor.
> > 
> > Signed-off-by: Inochi Amaoto <inochiama@gmail.com>
> 
> Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
> 
> I wonder though does this mean the numbers userspace can read from kernel 
> are bogus and if something can be done about that?
> 

I am not sure whether the clock rate can be read by the userspace.
At least it report the right baud speed by using stty.

Regards,
Inochi

> 
> > ---
> >  drivers/tty/serial/8250/8250_dw.c | 5 +++--
> >  1 file changed, 3 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c
> > index ab9e7f204260..51894c93c8a3 100644
> > --- a/drivers/tty/serial/8250/8250_dw.c
> > +++ b/drivers/tty/serial/8250/8250_dw.c
> > @@ -750,7 +750,7 @@ static const struct dw8250_platform_data dw8250_renesas_rzn1_data = {
> >  	.quirks = DW_UART_QUIRK_CPR_VALUE | DW_UART_QUIRK_IS_DMA_FC,
> >  };
> >  
> > -static const struct dw8250_platform_data dw8250_starfive_jh7100_data = {
> > +static const struct dw8250_platform_data dw8250_skip_set_rate_data = {
> >  	.usr_reg = DW_UART_USR,
> >  	.quirks = DW_UART_QUIRK_SKIP_SET_RATE,
> >  };
> > @@ -760,7 +760,8 @@ static const struct of_device_id dw8250_of_match[] = {
> >  	{ .compatible = "cavium,octeon-3860-uart", .data = &dw8250_octeon_3860_data },
> >  	{ .compatible = "marvell,armada-38x-uart", .data = &dw8250_armada_38x_data },
> >  	{ .compatible = "renesas,rzn1-uart", .data = &dw8250_renesas_rzn1_data },
> > -	{ .compatible = "starfive,jh7100-uart", .data = &dw8250_starfive_jh7100_data },
> > +	{ .compatible = "sophgo,sg2044-uart", .data = &dw8250_skip_set_rate_data },
> > +	{ .compatible = "starfive,jh7100-uart", .data = &dw8250_skip_set_rate_data },
> >  	{ /* Sentinel */ }
> >  };
> >  MODULE_DEVICE_TABLE(of, dw8250_of_match);
> >
Re: [PATCH v2 2/2] serial: 8250_dw: Add Sophgo SG2044 quirk
Posted by Ilpo Järvinen 1 month ago 
On Mon, 21 Oct 2024, Inochi Amaoto wrote:

> On Mon, Oct 21, 2024 at 11:52:38AM +0300, Ilpo Järvinen wrote:
> > On Mon, 21 Oct 2024, Inochi Amaoto wrote:
> > 
> > > SG2044 relys on an internal divisor when calculating bitrate, which
> > > means a wrong clock for the most common bitrates. So add a quirk for
> > > this uart device to skip the set rate call and only relys on the
> > > internal UART divisor.
> > > 
> > > Signed-off-by: Inochi Amaoto <inochiama@gmail.com>
> > 
> > Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
> > 
> > I wonder though does this mean the numbers userspace can read from kernel 
> > are bogus and if something can be done about that?
> > 
> 
> I am not sure whether the clock rate can be read by the userspace.
> At least it report the right baud speed by using stty.

Okay, I meant baud & other settings. Thanks for checking it.

-- 
 i.

> Regards,
> Inochi
> 
> > 
> > > ---
> > >  drivers/tty/serial/8250/8250_dw.c | 5 +++--
> > >  1 file changed, 3 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c
> > > index ab9e7f204260..51894c93c8a3 100644
> > > --- a/drivers/tty/serial/8250/8250_dw.c
> > > +++ b/drivers/tty/serial/8250/8250_dw.c
> > > @@ -750,7 +750,7 @@ static const struct dw8250_platform_data dw8250_renesas_rzn1_data = {
> > >  	.quirks = DW_UART_QUIRK_CPR_VALUE | DW_UART_QUIRK_IS_DMA_FC,
> > >  };
> > >  
> > > -static const struct dw8250_platform_data dw8250_starfive_jh7100_data = {
> > > +static const struct dw8250_platform_data dw8250_skip_set_rate_data = {
> > >  	.usr_reg = DW_UART_USR,
> > >  	.quirks = DW_UART_QUIRK_SKIP_SET_RATE,
> > >  };
> > > @@ -760,7 +760,8 @@ static const struct of_device_id dw8250_of_match[] = {
> > >  	{ .compatible = "cavium,octeon-3860-uart", .data = &dw8250_octeon_3860_data },
> > >  	{ .compatible = "marvell,armada-38x-uart", .data = &dw8250_armada_38x_data },
> > >  	{ .compatible = "renesas,rzn1-uart", .data = &dw8250_renesas_rzn1_data },
> > > -	{ .compatible = "starfive,jh7100-uart", .data = &dw8250_starfive_jh7100_data },
> > > +	{ .compatible = "sophgo,sg2044-uart", .data = &dw8250_skip_set_rate_data },
> > > +	{ .compatible = "starfive,jh7100-uart", .data = &dw8250_skip_set_rate_data },
> > >  	{ /* Sentinel */ }
> > >  };
> > >  MODULE_DEVICE_TABLE(of, dw8250_of_match);
> > > 
>
Re: [PATCH v2 2/2] serial: 8250_dw: Add Sophgo SG2044 quirk
Posted by Andy Shevchenko 1 month ago 
On Mon, Oct 21, 2024 at 01:17:55PM +0300, Ilpo Järvinen wrote:
> On Mon, 21 Oct 2024, Inochi Amaoto wrote:
> > On Mon, Oct 21, 2024 at 11:52:38AM +0300, Ilpo Järvinen wrote:
> > > On Mon, 21 Oct 2024, Inochi Amaoto wrote:

> > > > SG2044 relys on an internal divisor when calculating bitrate, which
> > > > means a wrong clock for the most common bitrates. So add a quirk for
> > > > this uart device to skip the set rate call and only relys on the
> > > > internal UART divisor.
> > > > 
> > > > Signed-off-by: Inochi Amaoto <inochiama@gmail.com>
> > > 
> > > Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
> > > 
> > > I wonder though does this mean the numbers userspace can read from kernel 
> > > are bogus and if something can be done about that?
> > 
> > I am not sure whether the clock rate can be read by the userspace.
> > At least it report the right baud speed by using stty.
> 
> Okay, I meant baud & other settings. Thanks for checking it.

oBut there is clock rate for user space. I think Ilpo has a point.

Documentation/ABI/testing/sysfs-tty:21:What:            /sys/class/tty/ttyS<x>/uartclk

-- 
With Best Regards,
Andy Shevchenko
Re: [PATCH v2 2/2] serial: 8250_dw: Add Sophgo SG2044 quirk
Posted by Andy Shevchenko 1 month ago 
On Mon, Oct 21, 2024 at 03:26:06PM +0800, Inochi Amaoto wrote:
> SG2044 relys on an internal divisor when calculating bitrate, which
> means a wrong clock for the most common bitrates. So add a quirk for
> this uart device to skip the set rate call and only relys on the
> internal UART divisor.

Assuming DT bindings are okay,
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

-- 
With Best Regards,
Andy Shevchenko

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