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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



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

Thread overview: 16+ 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 ` [PATCH v2 1/2] dt-bindings: serial: snps-dw-apb-uart: Add Sophgo SG2044 uarts Inochi Amaoto
2024-10-21 12:10   ` Conor Dooley
2024-10-21 12:18     ` Inochi Amaoto
2024-10-21 12:21       ` Conor Dooley
2024-10-21 12:23         ` Inochi Amaoto
2024-10-22 17:25           ` Conor Dooley
2024-10-23  0:32             ` Inochi Amaoto
2024-10-23 18:53               ` Conor Dooley
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  8:29   ` Andy Shevchenko
2024-10-21  8:52   ` Ilpo Järvinen
2024-10-21 10:08     ` Inochi Amaoto
2024-10-21 10:17       ` Ilpo Järvinen
2024-10-21 12:03         ` Andy Shevchenko [this message]

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