lkml.org 
[lkml]   [2023]   [Mar]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: [PATCH] i2c: lpi2c: cache peripheral clock rate
Date
Hi!

On Thu, 2023-03-09 at 15:37 +0100, Alexander Stein wrote:
>  From: Alexander Sverdlin <alexander.sverdlin@siemens.com>
> >
> > One of the reasons to do it is to save some CPU cycles on
> > cpu_freq_get()
> > under mutex. The second reason if the (false-positive) lockdep
> > splat caused
> > by the recursive feature of the "prepare_lock" (one clock instance
> > is I2C
> > peripheral clock and another is pcf85063 RTC as clock provider):
> >
> > ======================================================
> > WARNING: possible circular locking dependency detected
> > 5.15.71+... #1 Tainted: G           O
>
> Which kernel is this? Mainline or downstream vendor kernel?

found and tested on downstream vendor kernel.

[...]

>
>
> What if the peripheral clock rate changes? I guess a notifier similar
> to
> 90ad2cbe88c2 ("i2c: imx: use clk notifier for rate changes") should
> be added
> as well.
>

Good point! Thank you for the hint!

--
Alexander Sverdlin
Siemens AG
www.siemens.com
\
 
 \ /
  Last update: 2023-03-27 00:51    [W:0.031 / U:0.756 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site