Re: [PATCH v1 1/1] serial: max310x: Use clock-names property matching to recognize XTAL

From: Dennis Giaya
Date: Thu Jul 22 2021 - 17:05:18 EST


Andy,

I've tested this out on my hardware that uses an external oscillator
'osc' (as opposed to external crystal 'xtal').

With the relevant asl
Package () {"compatible", "maxim,max14830"},
Package ()
{"clock-frequency", 19200000},
Package () {"clock-names", "osc"},

Previously, the driver logic would default to 'xtal' and then compare
against the narrower frequency range and throw an error because 19.2MHz
was not allowed. With your patch, it proceeds as 'osc' and appears to
work as intended.

Thanks!
Dennis


On Thu, 2021-07-22 at 18:45 +0300, Andy Shevchenko wrote:
> On Thu, Jul 22, 2021 at 06:02:33PM +0300, Andy Shevchenko wrote:
> > Dennis reported that on ACPI-based systems the clock frequency
> > isn't enough to configure device properly. We have to respect
> > the clock source as well. To achieve this match the clock-names
> > property against "xtal" to recognize crystal connection.
>
> Dennis, please test this.
>
> ...
>
> > - s->clk = devm_clk_get_optional(dev, "osc");
> > + xtal = device_property_match_string(dev, "clock-names", "xtal")
> > >= 0;
>
> Meanwhile I will change this (not affects the testing in your case)
> to actually
> negative one as:
>
> ..., "osc") < 0;
>
> to be compatible with the original flow (in case there are two clock
> names, the
> "osc" has a priority).
>
>

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