All of lore.kernel.org
 help / color / mirror / Atom feed
From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: "Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>
Cc: Inochi Amaoto <inochiama@gmail.com>,
	Chen Wang <unicorn_wang@outlook.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Jiri Slaby <jirislaby@kernel.org>, Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Inochi Amaoto <inochiama@outlook.com>,
	Yixun Lan <dlan@gentoo.org>, LKML <linux-kernel@vger.kernel.org>,
	linux-serial <linux-serial@vger.kernel.org>,
	devicetree@vger.kernel.org, linux-riscv@lists.infradead.org
Subject: Re: [PATCH v2 2/2] serial: 8250_dw: Add Sophgo SG2044 quirk
Date: Mon, 21 Oct 2024 15:03:34 +0300	[thread overview]
Message-ID: <ZxZDFiUANo0Jqaai@smile.fi.intel.com> (raw)
In-Reply-To: <3dafd285-f56f-de2a-1544-b6ce092607b5@linux.intel.com>

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



_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

WARNING: multiple messages have this Message-ID (diff)
From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: "Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>
Cc: Inochi Amaoto <inochiama@gmail.com>,
	Chen Wang <unicorn_wang@outlook.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Jiri Slaby <jirislaby@kernel.org>, Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Inochi Amaoto <inochiama@outlook.com>,
	Yixun Lan <dlan@gentoo.org>, LKML <linux-kernel@vger.kernel.org>,
	linux-serial <linux-serial@vger.kernel.org>,
	devicetree@vger.kernel.org, linux-riscv@lists.infradead.org
Subject: Re: [PATCH v2 2/2] serial: 8250_dw: Add Sophgo SG2044 quirk
Date: Mon, 21 Oct 2024 15:03:34 +0300	[thread overview]
Message-ID: <ZxZDFiUANo0Jqaai@smile.fi.intel.com> (raw)
In-Reply-To: <3dafd285-f56f-de2a-1544-b6ce092607b5@linux.intel.com>

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



  reply	other threads:[~2024-10-21 12:04 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-10-21  7:26 [PATCH v2 0/2] serial: 8250_dw: Introduce SG2044 uart support Inochi Amaoto
2024-10-21  7:26 ` Inochi Amaoto
2024-10-21  7:26 ` [PATCH v2 1/2] dt-bindings: serial: snps-dw-apb-uart: Add Sophgo SG2044 uarts Inochi Amaoto
2024-10-21  7:26   ` Inochi Amaoto
2024-10-21 12:10   ` Conor Dooley
2024-10-21 12:10     ` Conor Dooley
2024-10-21 12:18     ` Inochi Amaoto
2024-10-21 12:18       ` Inochi Amaoto
2024-10-21 12:21       ` Conor Dooley
2024-10-21 12:21         ` Conor Dooley
2024-10-21 12:23         ` Inochi Amaoto
2024-10-21 12:23           ` Inochi Amaoto
2024-10-22 17:25           ` Conor Dooley
2024-10-22 17:25             ` Conor Dooley
2024-10-23  0:32             ` Inochi Amaoto
2024-10-23  0:32               ` Inochi Amaoto
2024-10-23 18:53               ` Conor Dooley
2024-10-23 18:53                 ` Conor Dooley
2024-10-21 18:00         ` Rob Herring
2024-10-21 18:00           ` Rob Herring
2024-10-21  7:26 ` [PATCH v2 2/2] serial: 8250_dw: Add Sophgo SG2044 quirk Inochi Amaoto
2024-10-21  7:26   ` Inochi Amaoto
2024-10-21  8:29   ` Andy Shevchenko
2024-10-21  8:29     ` Andy Shevchenko
2024-10-21  8:52   ` Ilpo Järvinen
2024-10-21  8:52     ` Ilpo Järvinen
2024-10-21 10:08     ` Inochi Amaoto
2024-10-21 10:08       ` Inochi Amaoto
2024-10-21 10:17       ` Ilpo Järvinen
2024-10-21 10:17         ` Ilpo Järvinen
2024-10-21 12:03         ` Andy Shevchenko [this message]
2024-10-21 12:03           ` Andy Shevchenko

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=ZxZDFiUANo0Jqaai@smile.fi.intel.com \
    --to=andriy.shevchenko@linux.intel.com \
    --cc=aou@eecs.berkeley.edu \
    --cc=conor+dt@kernel.org \
    --cc=devicetree@vger.kernel.org \
    --cc=dlan@gentoo.org \
    --cc=gregkh@linuxfoundation.org \
    --cc=ilpo.jarvinen@linux.intel.com \
    --cc=inochiama@gmail.com \
    --cc=inochiama@outlook.com \
    --cc=jirislaby@kernel.org \
    --cc=krzk+dt@kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-riscv@lists.infradead.org \
    --cc=linux-serial@vger.kernel.org \
    --cc=palmer@dabbelt.com \
    --cc=paul.walmsley@sifive.com \
    --cc=robh@kernel.org \
    --cc=unicorn_wang@outlook.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.