[v3] fbdev: Make CONFIG_FB_DEVICE optional for drivers

[PATCH v3 0/4] fbdev: Make CONFIG_FB_DEVICE optional for drivers

Posted by Chintan Patel 1 month, 1 week ago

This series makes CONFIG_FB_DEVICE optional for fbdev drivers that use
it only for sysfs interfaces, addressing Thomas Zimmermann’s TODO to
remove hard FB_DEVICE dependencies.

The series introduces a small helper, dev_of_fbinfo(), which returns
NULL when CONFIG_FB_DEVICE=n. This allows sysfs code paths to be skipped
via runtime checks, avoids #ifdef CONFIG_FB_DEVICE clutter, and keeps
full compile-time syntax checking.

Signed-off-by: Chintan Patel <chintanlike@gmail.com>
---
Changes in v3:
- Use PTR_IF() to conditionally include overlay_sysfs_group in 
  overlay_sysfs_groups
- Decouple variable definition and assignment in fbtft_sysfs_init/exit

Changes in v2:
- Add dev_of_fbinfo() helper (suggested by Geert Uytterhoeven)
- Replace #ifdef CONFIG_FB_DEVICE blocks with runtime NULL checks
- Switch to fb_dbg() / fb_info() logging (suggested by Thomas Zimmermann)

---

Chintan Patel (4):
  fb: Add dev_of_fbinfo() helper for optional sysfs support
  staging: fbtft: Make FB_DEVICE dependency optional
  fbdev: omapfb: Make FB_DEVICE dependency optional
  fbdev: sh_mobile_lcdc: Make FB_DEVICE dependency optional

 drivers/staging/fbtft/Kconfig                 |  5 ++++-
 drivers/staging/fbtft/fbtft-sysfs.c           | 20 +++++++++++++++----
 drivers/video/fbdev/omap2/omapfb/Kconfig      |  3 ++-
 .../video/fbdev/omap2/omapfb/omapfb-sysfs.c   | 16 +++++++++++----
 drivers/video/fbdev/sh_mobile_lcdcfb.c        | 12 ++++++++++-
 include/linux/fb.h                            |  9 +++++++++
 6 files changed, 54 insertions(+), 11 deletions(-)

-- 
2.43.0

Re: [PATCH v3 0/4] fbdev: Make CONFIG_FB_DEVICE optional for drivers

Posted by Andy Shevchenko 1 month, 1 week ago

On Mon, Dec 29, 2025 at 09:28:18PM -0800, Chintan Patel wrote:
> This series makes CONFIG_FB_DEVICE optional for fbdev drivers that use
> it only for sysfs interfaces, addressing Thomas Zimmermann’s TODO to
> remove hard FB_DEVICE dependencies.
> 
> The series introduces a small helper, dev_of_fbinfo(), which returns
> NULL when CONFIG_FB_DEVICE=n. This allows sysfs code paths to be skipped
> via runtime checks, avoids #ifdef CONFIG_FB_DEVICE clutter, and keeps
> full compile-time syntax checking.

> Signed-off-by: Chintan Patel <chintanlike@gmail.com>
> ---
> Changes in v3:
> - Use PTR_IF() to conditionally include overlay_sysfs_group in 
>   overlay_sysfs_groups
> - Decouple variable definition and assignment in fbtft_sysfs_init/exit

Any particular reasons you ignored my tag from v2?

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v3 0/4] fbdev: Make CONFIG_FB_DEVICE optional for drivers

Posted by Chintan Patel 1 month, 1 week ago


On 12/30/25 03:33, Andy Shevchenko wrote:
> On Mon, Dec 29, 2025 at 09:28:18PM -0800, Chintan Patel wrote:
>> This series makes CONFIG_FB_DEVICE optional for fbdev drivers that use
>> it only for sysfs interfaces, addressing Thomas Zimmermann’s TODO to
>> remove hard FB_DEVICE dependencies.
>>
>> The series introduces a small helper, dev_of_fbinfo(), which returns
>> NULL when CONFIG_FB_DEVICE=n. This allows sysfs code paths to be skipped
>> via runtime checks, avoids #ifdef CONFIG_FB_DEVICE clutter, and keeps
>> full compile-time syntax checking.
> 
>> Signed-off-by: Chintan Patel <chintanlike@gmail.com>
>> ---
>> Changes in v3:
>> - Use PTR_IF() to conditionally include overlay_sysfs_group in
>>    overlay_sysfs_groups
>> - Decouple variable definition and assignment in fbtft_sysfs_init/exit
> 
> Any particular reasons you ignored my tag from v2?
> 
Ah.. This is typo. I see what happened now. Looks like my script picked 
wrong or old patches instead of new updated one. Should I send v4 or v4 
is fine?

Re: [PATCH v3 0/4] fbdev: Make CONFIG_FB_DEVICE optional for drivers

Posted by Geert Uytterhoeven 1 month, 1 week ago

Hi Chintan.

On Tue, 30 Dec 2025 at 06:29, Chintan Patel <chintanlike@gmail.com> wrote:
> This series makes CONFIG_FB_DEVICE optional for fbdev drivers that use
> it only for sysfs interfaces, addressing Thomas Zimmermann’s TODO to
> remove hard FB_DEVICE dependencies.
>
> The series introduces a small helper, dev_of_fbinfo(), which returns
> NULL when CONFIG_FB_DEVICE=n. This allows sysfs code paths to be skipped
> via runtime checks, avoids #ifdef CONFIG_FB_DEVICE clutter, and keeps
> full compile-time syntax checking.
>
> Signed-off-by: Chintan Patel <chintanlike@gmail.com>
> ---
> Changes in v3:
> - Use PTR_IF() to conditionally include overlay_sysfs_group in
>   overlay_sysfs_groups
> - Decouple variable definition and assignment in fbtft_sysfs_init/exit
>
> Changes in v2:
> - Add dev_of_fbinfo() helper (suggested by Geert Uytterhoeven)

by Helge Deller, not me.

> - Replace #ifdef CONFIG_FB_DEVICE blocks with runtime NULL checks
> - Switch to fb_dbg() / fb_info() logging (suggested by Thomas Zimmermann)

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds