linux-kernel - Re: [PATCH v9 1/4] serial: 8250: Add 8250 port clock update method

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Message-ID: <ZdNvBtOlxo4FlLUH@smile.fi.intel.com>
Date: Mon, 19 Feb 2024 17:08:54 +0200
From: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To: Serge Semin <fancer.lancer@...il.com>
Cc: Andy Shevchenko <andy@...ck.fi.intel.com>,
	Serge Semin <Sergey.Semin@...kalelectronics.ru>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Jiri Slaby <jslaby@...e.com>,
	Alexey Malahov <Alexey.Malahov@...kalelectronics.ru>,
	Pavel Parkhomenko <Pavel.Parkhomenko@...kalelectronics.ru>,
	Maxime Ripard <mripard@...nel.org>, Will Deacon <will@...nel.org>,
	Russell King <linux@...linux.org.uk>,
	linux-arm-kernel@...ts.infradead.org, linux-serial@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v9 1/4] serial: 8250: Add 8250 port clock update method

On Fri, Feb 16, 2024 at 08:19:37PM +0300, Serge Semin wrote:
> On Thu, Feb 15, 2024 at 09:39:12PM +0200, Andy Shevchenko wrote:

..

(thanks for the detailed explanation why you have done it that way)

> If what you suggest is to replace the serial8250_update_uartclk() body
> with a direct uart_port::set_termios() invocation then I don't find it
> being much clearer really. The serial8250_update_uartclk() is
> currently specialized on doing one thing: adjusting the divider in
> case of the UART-clock change. If instead the entire
> serial8250_set_termios() method is called then for a reader it won't
> be easy to understand what is really required for a 8250 serial port
> to perceive the ref-clock change. But from the maintainability point
> of view I guess that it might be safer to just call
> serial8250_set_termios() indeed, since among the other things the
> later method implies the divider update too. Thus the maintainer won't
> need to support the two clock divider update implementations.

> From that perspective I agree, directly calling serial8250_set_termios()
> might be more suitable despite of it' doing more than required.

Would it be possible for you to cook the patch (and test on your HW,
since it seems the only user of that)?

-- 
With Best Regards,
Andy Shevchenko