linux-kernel - Re: [PATCH] pmbus: added possibility to change timeout for device update

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Message-ID: <20171102192108.GA6049@roeck-us.net>
Date:   Thu, 2 Nov 2017 12:21:08 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     Romain Porte <romain.porte@...ia.com>
Cc:     linux-hwmon@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] pmbus: added possibility to change timeout for device
 update

On Thu, Nov 02, 2017 at 05:17:21PM +0100, Romain Porte wrote:
> On 02/11/2017 14:58, Guenter Roeck wrote:
> >NACK, I'd rather drop the caching entirely, and possibly convert the
> >driver to
> >regmap for caching non-volatile registers.
> I need to familiarize myself with regmap then, it looks like a nice
> abstraction to have.
> 
> Do you think I can propose an intermediate patch for removing the cache
> support? (both time-based and data->valid based, so that every read actually
> performs a read, everytime)
> 

If you manage to do that, yes. That should limit reads to required reads,
not just drop ->valid and re-read every register for each attribute
access. Essentially, pmbus_update_device() should be completely gone.
That isn't easy to implement, which is why I never got to doing it.

Guenter