linux-kernel - Re: [PATCH v2 6/6] mfd: iqs62x: Do not change clock frequency during ATI

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Message-ID: <20210120084821.GS4903@dell>
Date:   Wed, 20 Jan 2021 08:48:21 +0000
From:   Lee Jones <lee.jones@...aro.org>
To:     Jeff LaBundy <jeff@...undy.com>
Cc:     linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 6/6] mfd: iqs62x: Do not change clock frequency during
 ATI

On Sun, 17 Jan 2021, Jeff LaBundy wrote:

> After a reset event, the device automatically triggers ATI at the
> default core clock frequency (16 MHz). Soon afterward, the driver
> loads firmware which may attempt to lower the frequency.
> 
> If this initial ATI cycle is still in progress when the frequency
> is changed, however, the device incorrectly reports channels 0, 1
> and 2 to be in a state of touch once ATI finally completes.
> 
> To solve this problem, wait until ATI is complete before lowering
> the frequency. Because this particular ATI cycle occurs following
> a reset event, its duration is predictable and a simple delay can
> suffice.
> 
> Signed-off-by: Jeff LaBundy <jeff@...undy.com>
> Acked-for-MFD-by: Lee Jones <lee.jones@...aro.org>
> ---
> Changes in v2:
>   - Added Acked-for-MFD-by trailer
> 
>  drivers/mfd/iqs62x.c | 9 +++++++++
>  1 file changed, 9 insertions(+)

Applied, thanks.

-- 
Lee Jones [李琼斯]
Senior Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
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