linux-kernel - Re: [PATCH 1/3] fbtft: Make sysfs and dev_*() logging conditional on FB

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Message-ID: <89b08d9a-9f96-40f0-9ae6-e54b16b65879@gmail.com>
Date: Tue, 9 Dec 2025 20:24:47 -0800
From: Chintan Patel <chintanlike@...il.com>
To: Thomas Zimmermann <tzimmermann@...e.de>, linux-fbdev@...r.kernel.org,
 linux-staging@...ts.linux.dev, linux-omap@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org,
 andy@...nel.org, deller@....de, gregkh@...uxfoundation.org
Subject: Re: [PATCH 1/3] fbtft: Make sysfs and dev_*() logging conditional on
 FB_DEVICE

Hi Thomas,

On 12/8/25 23:25, Thomas Zimmermann wrote:
> Hi
> 
> Am 09.12.25 um 05:27 schrieb Chintan Patel:
>> The fbtft core and sysfs implementation unconditionally dereference
>> fb_info->dev and register sysfs attributes. When FB_DEVICE=n, these
>> fields are unavailable, leading to build failures.
>>
>> This patch wraps all sysfs attribute creation/removal and dev_dbg/ 
>> dev_info
>> logging in #ifdef CONFIG_FB_DEVICE, with pr_*() fallbacks for the
>> non-FB_DEVICE case. This makes fbtft fully buildable when FB_DEVICE is
>> disabled.
>>
>> Signed-off-by: Chintan Patel <chintanlike@...il.com>
>> ---
>>   drivers/staging/fbtft/fbtft-core.c  | 20 ++++++++++++++++++--
>>   drivers/staging/fbtft/fbtft-sysfs.c |  8 ++++++++
>>   2 files changed, 26 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/staging/fbtft/fbtft-core.c b/drivers/staging/ 
>> fbtft/fbtft-core.c
>> index 9e7b84071174..dc967bdeabe8 100644
>> --- a/drivers/staging/fbtft/fbtft-core.c
>> +++ b/drivers/staging/fbtft/fbtft-core.c
>> @@ -365,9 +365,14 @@ static int fbtft_fb_setcolreg(unsigned int regno, 
>> unsigned int red,
>>       unsigned int val;
>>       int ret = 1;
>> +#ifdef CONFIG_FB_DEVICE
>>       dev_dbg(info->dev,
> 
> Rather use fb_dbg() [1] and similar helpers for logging. They only need 
> the info pointer and do the correct output by themselves.
> 
> [1] https://elixir.bootlin.com/linux/v6.18/source/include/linux/fb.h#L895

Thank you for this pointer - I actually didnt now this existed. Will do v2.