linux-kernel - Re: [PATCH v3 0/4] cros_kbd_led_backlight: allow binding through cros

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Message-ID: <edc637ff-d26d-4500-8ad3-23bf7a9d527e@t-8ch.de>
Date: Fri, 31 May 2024 17:59:01 +0200
From: Thomas Weißschuh <linux@...ssschuh.net>
To: Lee Jones <lee@...nel.org>
Cc: Benson Leung <bleung@...omium.org>, 
	Guenter Roeck <groeck@...omium.org>, Tzung-Bi Shih <tzungbi@...nel.org>, Pavel Machek <pavel@....cz>, 
	chrome-platform@...ts.linux.dev, linux-kernel@...r.kernel.org, Dustin Howett <dustin@...ett.net>, 
	Mario Limonciello <mario.limonciello@....com>, linux-leds@...r.kernel.org, 
	Rajas Paranjpe <paranjperajas@...il.com>
Subject: Re: [PATCH v3 0/4] cros_kbd_led_backlight: allow binding through
 cros_ec mfd device

On 2024-05-31 16:53:56+0000, Lee Jones wrote:
> On Fri, 31 May 2024, Thomas Weißschuh wrote:
> 
> > On 2024-05-31 16:35:30+0000, Lee Jones wrote:
> > > On Sun, 26 May 2024, Thomas Weißschuh wrote:
> > > 
> > > > Extend the cros_ec MFD device to also load cros_kbd_led_backlight
> > > > when the EC reports EC_FEATURE_PWM_KEYB.
> > > > As the driver can now be probed multiple times, some preparation in the
> > > > LED core is necessary to avoid name collisions.
> > > > 
> > > > Patch 1 is a general cleanup for the LED core.
> > > > Patch 2 modifies the LED core to skip the default collision handling.
> > > > Patch 3 adds the new probing logic to cros_kbd_led_backlight.
> > > > Patch 4 wires up the driver to the cros_ec mfd devices.
> > > > 
> > > > The helper keyboard_led_is_mfd_device is a bit iffy.
> > > > But using match data doesn't work.
> > > > 
> > > > * driver_data from platform_device_id is overwritten by the mfd platform data
> > > > * Setting the driver_data in drivers/mfd/cros_ec_dev.c would expose the
> > > > internals of cros_kbd_led_backlight
> > > > 
> > > > Tested on a Framework 13 AMD, Firmware 3.05, and a Jinlon Chromebook.
> > > > 
> > > > To: Lee Jones <lee@...nel.org>
> > > > To: Benson Leung <bleung@...omium.org>
> > > > To: Guenter Roeck <groeck@...omium.org>
> > > > To: Tzung-Bi Shih <tzungbi@...nel.org>
> > > > To: Pavel Machek <pavel@....cz>
> > > > Cc: chrome-platform@...ts.linux.dev
> > > > Cc: linux-kernel@...r.kernel.org
> > > > Cc: Dustin Howett <dustin@...ett.net>
> > > > Cc: Mario Limonciello <mario.limonciello@....com>
> > > > Cc: linux-leds@...r.kernel.org
> > > > Cc: Rajas Paranjpe <paranjperajas@...il.com>
> > > > Signed-off-by: Thomas Weißschuh <linux@...ssschuh.net>
> > > > 
> > > > Changes in v3:
> > > > - Avoid probing multiple times (Confirmed by Rajas)
> > > > - Add Kconfig dependency on MFD_CROS_EC_DEV
> > > > - Link to v2: https://lore.kernel.org/r/20240511-cros_ec-kbd-led-framework-v2-0-b20c48109e46@weissschuh.net
> > > > 
> > > > Changes in v2:
> > > > - Fix build with CONFIG_MFD_CROS_EC_DEV=n (kernel test robot)
> > > > - Split out mfd registration into own commit (Lee)
> > > > - Simplify keyboard_led_is_mfd_device() with mfd_get_cell()
> > > > - Link to v1: https://lore.kernel.org/r/20240505-cros_ec-kbd-led-framework-v1-1-bfcca69013d2@weissschuh.net
> > > > 
> > > > ---
> > > > Thomas Weißschuh (4):
> > > >       leds: class: warn about name collisions earlier
> > > >       leds: add flag to avoid automatic renaming of led devices
> > > >       platform/chrome: cros_kbd_led_backlight: allow binding through mfd device
> > > >       mfd: cros_ec: Register keyboard backlight subdevice
> > > > 
> > > >  drivers/leds/led-class.c                         |  9 +++---
> > > >  drivers/mfd/cros_ec_dev.c                        |  9 ++++++
> > > >  drivers/platform/chrome/Kconfig                  |  2 +-
> > > >  drivers/platform/chrome/cros_kbd_led_backlight.c | 40 ++++++++++++++++++++++--
> > > >  include/linux/leds.h                             |  1 +
> > > >  5 files changed, 54 insertions(+), 7 deletions(-)
> > > 
> > > Looks okay.
> > 
> > Thanks.
> > 
> > > Does the platform patch need to be applied with the others?
> > 
> > Each patch depends on all its predecessors.
> > (but I'm not sure I understood your question)
> 
> Does the Platform patch have 'build-time' deps on the others?

Yes.

Patch 3 makes use of LED_REJECT_NAME_CONFLICT which was introduced in Patch 2.

Patch 1, 2, 3 have build-time deps on their predecessors.
Patch 4 has a run-time deps on Patch 3.