linux-kernel - Re: [PATCH] drivers: hwmon: add EMC2101 driver

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Message-ID: <9df1cc49-34bd-42d4-96dc-ec9b512e0c5f@roeck-us.net>
Date: Thu, 3 Jul 2025 17:25:28 -0700
From: Guenter Roeck <linux@...ck-us.net>
To: Álvaro Fernández Rojas <noltari@...il.com>
Cc: Krzysztof Kozlowski <krzk@...nel.org>, jdelvare@...e.com,
	robh@...nel.org, krzk+dt@...nel.org, conor+dt@...nel.org,
	corbet@....net, linux-hwmon@...r.kernel.org,
	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-doc@...r.kernel.org
Subject: Re: [PATCH] drivers: hwmon: add EMC2101 driver

On Thu, Jul 03, 2025 at 09:23:41AM +0200, Álvaro Fernández Rojas wrote:
> >
> > Add a comment describing what you are protecting here. It looks so far
> > like you could just use regmap and drop the mutex, but I didn't check
> > thoroughly.
> 
> The EMC2101 datasheet is explicit about the Look Up Table registers
> (REG_FAN_LUT_TEMP and REG_FAN_LUT_SPEED) being RO if FAN_LUT_DISABLE
> isn't set, so I believe that we need the mutex even if we switch to
> regmap.
> I will add an explanation with that in the next version.
> Should I still switch the implementation to regmap considering that we
> need a mutex?
> 
What does r/w vs. r/o register access have to do with locking ?

Guenter