linux-kernel - Re: Versaclock usage and improvement question

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Message-ID: <1352fbee-c768-315e-4042-d666db3d9456@gmail.com>
Date:   Tue, 24 Mar 2020 18:30:35 +0100
From:   Marek Vasut <marek.vasut@...il.com>
To:     Adam Ford <aford173@...il.com>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>,
        linux-clk <linux-clk@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: Versaclock usage and improvement question

On 3/24/20 6:15 PM, Adam Ford wrote:
> Marek,

Hi,

> I am working on a board that uses two versaclock chips using different
> i2c buses, but it appears to the driver is hard-coding the names of
> the clocks.  This appears to be a problem when the second instance is
> loaded, it fails, because the clock names already exist.  I am
> inquiring to you as how you'd prefer to see the clock names generated
> so we can do multiple instances. I am planning on using kasprintf and
> following a pattern similar to drivers/clk/keystone/sci-clk.c.

I never had a board with two of them indeed, sorry.

> Secondly, our Versaclock chips are un-programmed, so we need to both
> enable the clock signal and set the output type which means adding a
> few device tree options.  I am curious to know if you have an opinion
> on how the new flags should be named.

I'd say, send an RFC patch and let's move on from there ?
The chips I use are factory pre-programmed btw.

> Lastly, we're going to use the versaclock to drive multiple devices,
> and some of them do not call the function to enable the clocks, so we
> need some method to force the clocks on.  Is there a method to forcing
> the clock outputs on similar to a gpio-hog holding a GPIO line in a
> known state?

I think something around assigned-clock DT props might help here ?

-- 
Best regards,
Marek Vasut