[PATCH v2 00/10] backlight: Replace struct fb_info in interfaces

[PATCH v2 00/10] backlight: Replace struct fb_info in interfaces

[Thomas Zimmermann]

Backlight drivers implement struct backlight_ops.check_fb, which
uses struct fb_info in its interface. Replace the callback with one
that does not use fb_info.

In DRM, we have several drivers that implement backlight support. By
including <linux/backlight.h> these drivers depend on <linux/fb.h>.
At the same time, fbdev is deprecated for new drivers and likely to
be replaced on many systems.

This patchset is part of a larger effort to implement the backlight
code without depending on fbdev.

Patch 1 makes the backlight core match backlight and framebuffer
devices via struct fb_info.bl_dev. Patches 2 to 9 then go through
drivers and remove unnecessary implementations of check_fb. Finally,
patch 10 replaces the check_fb hook with controls_device, which
uses the framebuffer's Linux device instead of the framebuffer.

v2:
	* fix hid-picolcd for CONFIG_FB_BACKLIGHT=n
	* fixes to commit messages

Thomas Zimmermann (10):
  backlight: Match backlight device against struct fb_info.bl_dev
  auxdisplay/ht16k33: Remove struct backlight_ops.check_fb
  hid/hid-picolcd: Fix initialization order
  hid/hid-picolcd: Remove struct backlight_ops.check_fb
  backlight/aat2870-backlight: Remove struct backlight.check_fb
  backlight/pwm-backlight: Remove struct backlight_ops.check_fb
  fbdev/sh_mobile_lcdc_fb: Remove struct backlight_ops.check_fb
  fbdev/ssd1307fb: Init backlight before registering framebuffer
  fbdev/ssd1307fb: Remove struct backlight_ops.check_fb
  backlight: Add controls_device callback to struct backlight_ops

 drivers/auxdisplay/ht16k33.c             |  8 ------
 drivers/hid/hid-picolcd_backlight.c      |  7 ------
 drivers/hid/hid-picolcd_core.c           | 14 +++++------
 drivers/hid/hid-picolcd_fb.c             |  6 +++++
 drivers/video/backlight/aat2870_bl.c     |  7 ------
 drivers/video/backlight/backlight.c      |  9 +++++--
 drivers/video/backlight/bd6107.c         | 12 ++++-----
 drivers/video/backlight/gpio_backlight.c | 12 ++++-----
 drivers/video/backlight/lv5207lp.c       | 12 ++++-----
 drivers/video/backlight/pwm_bl.c         | 12 ---------
 drivers/video/fbdev/sh_mobile_lcdcfb.c   |  7 ------
 drivers/video/fbdev/ssd1307fb.c          | 31 +++++++++---------------
 include/linux/backlight.h                | 16 ++++++------
 include/linux/pwm_backlight.h            |  1 -
 14 files changed, 57 insertions(+), 97 deletions(-)

-- 
2.43.0

[PATCH v2 01/10] backlight: Match backlight device against struct fb_info.bl_dev

[Thomas Zimmermann]

Framebuffer drivers for devices with dedicated backlight are supposed
to set struct fb_info.bl_dev to the backlight's respective device. Use
the value to match backlight and framebuffer in the backlight core code.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
---
 drivers/video/backlight/backlight.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/video/backlight/backlight.c b/drivers/video/backlight/backlight.c
index 86e1cdc8e3697..48844a4f28ad3 100644
--- a/drivers/video/backlight/backlight.c
+++ b/drivers/video/backlight/backlight.c
@@ -98,7 +98,8 @@ static int fb_notifier_callback(struct notifier_block *self,
 {
 	struct backlight_device *bd;
 	struct fb_event *evdata = data;
-	int node = evdata->info->node;
+	struct fb_info *info = evdata->info;
+	int node = info->node;
 	int fb_blank = 0;
 
 	/* If we aren't interested in this event, skip it immediately ... */
@@ -110,8 +111,12 @@ static int fb_notifier_callback(struct notifier_block *self,
 
 	if (!bd->ops)
 		goto out;
-	if (bd->ops->check_fb && !bd->ops->check_fb(bd, evdata->info))
+	else if (bd->ops->check_fb && !bd->ops->check_fb(bd, info))
 		goto out;
+#if IS_ENABLED(CONFIG_FB_BACKLIGHT)
+	else if (info->bl_dev && info->bl_dev != bd)
+		goto out;
+#endif
 
 	fb_blank = *(int *)evdata->data;
 	if (fb_blank == FB_BLANK_UNBLANK && !bd->fb_bl_on[node]) {
-- 
2.43.0

Re: [PATCH v2 01/10] backlight: Match backlight device against struct fb_info.bl_dev

[Andy Shevchenko]

On Wed, Feb 21, 2024 at 10:41:28AM +0100, Thomas Zimmermann wrote:
> Framebuffer drivers for devices with dedicated backlight are supposed
> to set struct fb_info.bl_dev to the backlight's respective device. Use
> the value to match backlight and framebuffer in the backlight core code.

...

>  	if (!bd->ops)
>  		goto out;
> -	if (bd->ops->check_fb && !bd->ops->check_fb(bd, evdata->info))
> +	else if (bd->ops->check_fb && !bd->ops->check_fb(bd, info))

What's the point of adding redundant 'else'?

>  		goto out;
> +#if IS_ENABLED(CONFIG_FB_BACKLIGHT)
> +	else if (info->bl_dev && info->bl_dev != bd)

Ditto.

> +		goto out;
> +#endif

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v2 01/10] backlight: Match backlight device against struct fb_info.bl_dev

[Thomas Zimmermann]

Hi

Am 21.02.24 um 15:34 schrieb Andy Shevchenko:
> On Wed, Feb 21, 2024 at 10:41:28AM +0100, Thomas Zimmermann wrote:
>> Framebuffer drivers for devices with dedicated backlight are supposed
>> to set struct fb_info.bl_dev to the backlight's respective device. Use
>> the value to match backlight and framebuffer in the backlight core code.
> ...
>
>>   	if (!bd->ops)
>>   		goto out;
>> -	if (bd->ops->check_fb && !bd->ops->check_fb(bd, evdata->info))
>> +	else if (bd->ops->check_fb && !bd->ops->check_fb(bd, info))
> What's the point of adding redundant 'else'?
>
>>   		goto out;
>> +#if IS_ENABLED(CONFIG_FB_BACKLIGHT)
>> +	else if (info->bl_dev && info->bl_dev != bd)
> Ditto.

They group these tests into one single block of code; signaling that 
these tests serve the same purpose.

Best regards
Thomas

>
>> +		goto out;
>> +#endif

-- 
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)

Re: [PATCH v2 01/10] backlight: Match backlight device against struct fb_info.bl_dev

[Andy Shevchenko]

On Wed, Feb 21, 2024 at 5:45 PM Thomas Zimmermann <tzimmermann@suse.de> wrote:
> Am 21.02.24 um 15:34 schrieb Andy Shevchenko:
> > On Wed, Feb 21, 2024 at 10:41:28AM +0100, Thomas Zimmermann wrote:
> >> Framebuffer drivers for devices with dedicated backlight are supposed
> >> to set struct fb_info.bl_dev to the backlight's respective device. Use
> >> the value to match backlight and framebuffer in the backlight core code.

...

> >>      if (!bd->ops)
> >>              goto out;
> >> -    if (bd->ops->check_fb && !bd->ops->check_fb(bd, evdata->info))
> >> +    else if (bd->ops->check_fb && !bd->ops->check_fb(bd, info))
> > What's the point of adding redundant 'else'?
> >
> >>              goto out;
> >> +#if IS_ENABLED(CONFIG_FB_BACKLIGHT)
> >> +    else if (info->bl_dev && info->bl_dev != bd)
> > Ditto.
>
> They group these tests into one single block of code; signaling that
> these tests serve the same purpose.

Commit message has nothing about this.
Also if needed, it should be a separate change.

> >> +            goto out;
> >> +#endif

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v2 01/10] backlight: Match backlight device against struct fb_info.bl_dev

[Lee Jones]

On Wed, 21 Feb 2024, Thomas Zimmermann wrote:

> Framebuffer drivers for devices with dedicated backlight are supposed
> to set struct fb_info.bl_dev to the backlight's respective device. Use
> the value to match backlight and framebuffer in the backlight core code.
> 
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
> Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
> ---
>  drivers/video/backlight/backlight.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/video/backlight/backlight.c b/drivers/video/backlight/backlight.c
> index 86e1cdc8e3697..48844a4f28ad3 100644
> --- a/drivers/video/backlight/backlight.c
> +++ b/drivers/video/backlight/backlight.c
> @@ -98,7 +98,8 @@ static int fb_notifier_callback(struct notifier_block *self,
>  {
>  	struct backlight_device *bd;
>  	struct fb_event *evdata = data;
> -	int node = evdata->info->node;
> +	struct fb_info *info = evdata->info;
> +	int node = info->node;
>  	int fb_blank = 0;
>  
>  	/* If we aren't interested in this event, skip it immediately ... */
> @@ -110,8 +111,12 @@ static int fb_notifier_callback(struct notifier_block *self,
>  
>  	if (!bd->ops)
>  		goto out;
> -	if (bd->ops->check_fb && !bd->ops->check_fb(bd, evdata->info))
> +	else if (bd->ops->check_fb && !bd->ops->check_fb(bd, info))
>  		goto out;
> +#if IS_ENABLED(CONFIG_FB_BACKLIGHT)

I don't want #ifery in C files.

Please find another way.

> +	else if (info->bl_dev && info->bl_dev != bd)
> +		goto out;
> +#endif
>  
>  	fb_blank = *(int *)evdata->data;
>  	if (fb_blank == FB_BLANK_UNBLANK && !bd->fb_bl_on[node]) {
> -- 
> 2.43.0
> 

-- 
Lee Jones [李琼斯]

[PATCH v2 02/10] auxdisplay/ht16k33: Remove struct backlight_ops.check_fb

[Thomas Zimmermann]

The driver sets struct fb_info.bl_dev to the correct backlight
device. Thus rely on the backlight core code to match backlight
and framebuffer devices, and remove the extra check_fb function
from struct backlight_ops.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Robin van der Gracht <robin@protonic.nl>
Acked-by: Robin van der Gracht <robin@protonic.nl>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
---
 drivers/auxdisplay/ht16k33.c | 8 --------
 1 file changed, 8 deletions(-)

diff --git a/drivers/auxdisplay/ht16k33.c b/drivers/auxdisplay/ht16k33.c
index a90430b7d07ba..0a858db32486b 100644
--- a/drivers/auxdisplay/ht16k33.c
+++ b/drivers/auxdisplay/ht16k33.c
@@ -325,16 +325,8 @@ static int ht16k33_bl_update_status(struct backlight_device *bl)
 	return ht16k33_brightness_set(priv, brightness);
 }
 
-static int ht16k33_bl_check_fb(struct backlight_device *bl, struct fb_info *fi)
-{
-	struct ht16k33_priv *priv = bl_get_data(bl);
-
-	return (fi == NULL) || (fi->par == priv);
-}
-
 static const struct backlight_ops ht16k33_bl_ops = {
 	.update_status	= ht16k33_bl_update_status,
-	.check_fb	= ht16k33_bl_check_fb,
 };
 
 /*
-- 
2.43.0

Re: [PATCH v2 02/10] auxdisplay/ht16k33: Remove struct backlight_ops.check_fb

[Andy Shevchenko]

On Wed, Feb 21, 2024 at 10:41:29AM +0100, Thomas Zimmermann wrote:
> The driver sets struct fb_info.bl_dev to the correct backlight
> device. Thus rely on the backlight core code to match backlight
> and framebuffer devices, and remove the extra check_fb function
> from struct backlight_ops.

check_fb()

Acked-by: Andy Shevchenko <andy@kernel.org>

-- 
With Best Regards,
Andy Shevchenko

[PATCH v2 03/10] hid/hid-picolcd: Fix initialization order

[Thomas Zimmermann]

For drivers that support backlight, LCD and fbdev devices, fbdev has
to be initialized last. See documentation for struct fbinfo.bl_dev.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Cc: "Bruno Prémont" <bonbons@linux-vserver.org>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
---
 drivers/hid/hid-picolcd_core.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/hid/hid-picolcd_core.c b/drivers/hid/hid-picolcd_core.c
index bbda231a7ce30..5ddebe25eb91f 100644
--- a/drivers/hid/hid-picolcd_core.c
+++ b/drivers/hid/hid-picolcd_core.c
@@ -474,11 +474,6 @@ static int picolcd_probe_lcd(struct hid_device *hdev, struct picolcd_data *data)
 	if (error)
 		goto err;
 
-	/* Set up the framebuffer device */
-	error = picolcd_init_framebuffer(data);
-	if (error)
-		goto err;
-
 	/* Setup lcd class device */
 	error = picolcd_init_lcd(data, picolcd_out_report(REPORT_CONTRAST, hdev));
 	if (error)
@@ -489,6 +484,11 @@ static int picolcd_probe_lcd(struct hid_device *hdev, struct picolcd_data *data)
 	if (error)
 		goto err;
 
+	/* Set up the framebuffer device */
+	error = picolcd_init_framebuffer(data);
+	if (error)
+		goto err;
+
 	/* Setup the LED class devices */
 	error = picolcd_init_leds(data, picolcd_out_report(REPORT_LED_STATE, hdev));
 	if (error)
@@ -502,9 +502,9 @@ static int picolcd_probe_lcd(struct hid_device *hdev, struct picolcd_data *data)
 	return 0;
 err:
 	picolcd_exit_leds(data);
+	picolcd_exit_framebuffer(data);
 	picolcd_exit_backlight(data);
 	picolcd_exit_lcd(data);
-	picolcd_exit_framebuffer(data);
 	picolcd_exit_cir(data);
 	picolcd_exit_keys(data);
 	return error;
@@ -623,9 +623,9 @@ static void picolcd_remove(struct hid_device *hdev)
 	/* Cleanup LED */
 	picolcd_exit_leds(data);
 	/* Clean up the framebuffer */
+	picolcd_exit_framebuffer(data);
 	picolcd_exit_backlight(data);
 	picolcd_exit_lcd(data);
-	picolcd_exit_framebuffer(data);
 	/* Cleanup input */
 	picolcd_exit_cir(data);
 	picolcd_exit_keys(data);
-- 
2.43.0

[PATCH v2 04/10] hid/hid-picolcd: Remove struct backlight_ops.check_fb

[Thomas Zimmermann]

Update the driver to initialize struct fb_info.bl_dev to its backlight
device, if any. Thus rely on the backlight core code to match backlight
and framebuffer devices, and remove the extra check_fb function from
struct backlight_ops.

v2:
	* protect against CONFIG_FB_BACKLIGHT (Javier, kernel test robot)
	* reword commit message (Daniel)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Cc: "Bruno Prémont" <bonbons@linux-vserver.org>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
---
 drivers/hid/hid-picolcd_backlight.c | 7 -------
 drivers/hid/hid-picolcd_fb.c        | 6 ++++++
 2 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/drivers/hid/hid-picolcd_backlight.c b/drivers/hid/hid-picolcd_backlight.c
index 5bd2a8c4bbd66..08d16917eb60b 100644
--- a/drivers/hid/hid-picolcd_backlight.c
+++ b/drivers/hid/hid-picolcd_backlight.c
@@ -9,7 +9,6 @@
 
 #include <linux/hid.h>
 
-#include <linux/fb.h>
 #include <linux/backlight.h>
 
 #include "hid-picolcd.h"
@@ -39,15 +38,9 @@ static int picolcd_set_brightness(struct backlight_device *bdev)
 	return 0;
 }
 
-static int picolcd_check_bl_fb(struct backlight_device *bdev, struct fb_info *fb)
-{
-	return fb && fb == picolcd_fbinfo((struct picolcd_data *)bl_get_data(bdev));
-}
-
 static const struct backlight_ops picolcd_blops = {
 	.update_status  = picolcd_set_brightness,
 	.get_brightness = picolcd_get_brightness,
-	.check_fb       = picolcd_check_bl_fb,
 };
 
 int picolcd_init_backlight(struct picolcd_data *data, struct hid_report *report)
diff --git a/drivers/hid/hid-picolcd_fb.c b/drivers/hid/hid-picolcd_fb.c
index d7dddd99d325e..750206f5fc674 100644
--- a/drivers/hid/hid-picolcd_fb.c
+++ b/drivers/hid/hid-picolcd_fb.c
@@ -493,6 +493,12 @@ int picolcd_init_framebuffer(struct picolcd_data *data)
 	info->fix = picolcdfb_fix;
 	info->fix.smem_len   = PICOLCDFB_SIZE*8;
 
+#ifdef CONFIG_FB_BACKLIGHT
+#ifdef CONFIG_HID_PICOLCD_BACKLIGHT
+	info->bl_dev = data->backlight;
+#endif
+#endif
+
 	fbdata = info->par;
 	spin_lock_init(&fbdata->lock);
 	fbdata->picolcd = data;
-- 
2.43.0

[PATCH v2 05/10] backlight/aat2870-backlight: Remove struct backlight.check_fb

[Thomas Zimmermann]

The driver's implementation of check_fb always returns true, which
is the default if no implementation has been set. So remove the code
from the driver.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
---
 drivers/video/backlight/aat2870_bl.c | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/drivers/video/backlight/aat2870_bl.c b/drivers/video/backlight/aat2870_bl.c
index 81fde3abb92c4..b4c3354a1a8a6 100644
--- a/drivers/video/backlight/aat2870_bl.c
+++ b/drivers/video/backlight/aat2870_bl.c
@@ -12,7 +12,6 @@
 #include <linux/platform_device.h>
 #include <linux/mutex.h>
 #include <linux/delay.h>
-#include <linux/fb.h>
 #include <linux/backlight.h>
 #include <linux/mfd/aat2870.h>
 
@@ -90,15 +89,9 @@ static int aat2870_bl_update_status(struct backlight_device *bd)
 	return 0;
 }
 
-static int aat2870_bl_check_fb(struct backlight_device *bd, struct fb_info *fi)
-{
-	return 1;
-}
-
 static const struct backlight_ops aat2870_bl_ops = {
 	.options = BL_CORE_SUSPENDRESUME,
 	.update_status = aat2870_bl_update_status,
-	.check_fb = aat2870_bl_check_fb,
 };
 
 static int aat2870_bl_probe(struct platform_device *pdev)
-- 
2.43.0

[PATCH v2 06/10] backlight/pwm-backlight: Remove struct backlight_ops.check_fb

[Thomas Zimmermann]

The internal check_fb callback from struct pwm_bl_data is never
implemented. The driver's implementation of check_fb always
returns true, which is the backlight core's default if no
implementation has been set. So remove the code from the driver.

v2:
	* reword commit message

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Cc: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
---
 drivers/video/backlight/pwm_bl.c | 12 ------------
 include/linux/pwm_backlight.h    |  1 -
 2 files changed, 13 deletions(-)

diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index ffcebf6aa76a9..61d30bc98eea5 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -11,7 +11,6 @@
 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/platform_device.h>
-#include <linux/fb.h>
 #include <linux/backlight.h>
 #include <linux/err.h>
 #include <linux/pwm.h>
@@ -34,7 +33,6 @@ struct pwm_bl_data {
 					  int brightness);
 	void			(*notify_after)(struct device *,
 					int brightness);
-	int			(*check_fb)(struct device *, struct fb_info *);
 	void			(*exit)(struct device *);
 };
 
@@ -129,17 +127,8 @@ static int pwm_backlight_update_status(struct backlight_device *bl)
 	return 0;
 }
 
-static int pwm_backlight_check_fb(struct backlight_device *bl,
-				  struct fb_info *info)
-{
-	struct pwm_bl_data *pb = bl_get_data(bl);
-
-	return !pb->check_fb || pb->check_fb(pb->dev, info);
-}
-
 static const struct backlight_ops pwm_backlight_ops = {
 	.update_status	= pwm_backlight_update_status,
-	.check_fb	= pwm_backlight_check_fb,
 };
 
 #ifdef CONFIG_OF
@@ -482,7 +471,6 @@ static int pwm_backlight_probe(struct platform_device *pdev)
 
 	pb->notify = data->notify;
 	pb->notify_after = data->notify_after;
-	pb->check_fb = data->check_fb;
 	pb->exit = data->exit;
 	pb->dev = &pdev->dev;
 	pb->enabled = false;
diff --git a/include/linux/pwm_backlight.h b/include/linux/pwm_backlight.h
index cdd2ac366bc72..0bf80e98d5b40 100644
--- a/include/linux/pwm_backlight.h
+++ b/include/linux/pwm_backlight.h
@@ -19,7 +19,6 @@ struct platform_pwm_backlight_data {
 	int (*notify)(struct device *dev, int brightness);
 	void (*notify_after)(struct device *dev, int brightness);
 	void (*exit)(struct device *dev);
-	int (*check_fb)(struct device *dev, struct fb_info *info);
 };
 
 #endif
-- 
2.43.0

[PATCH v2 07/10] fbdev/sh_mobile_lcdc_fb: Remove struct backlight_ops.check_fb

[Thomas Zimmermann]

The driver sets struct fb_info.bl_dev to the correct backlight
device. Thus rely on the backlight core code to match backlight
and framebuffer devices, and remove the extra check_fb function
from struct backlight_ops.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
---
 drivers/video/fbdev/sh_mobile_lcdcfb.c | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/drivers/video/fbdev/sh_mobile_lcdcfb.c b/drivers/video/fbdev/sh_mobile_lcdcfb.c
index eb2297b37504c..bf34c8ec1a26c 100644
--- a/drivers/video/fbdev/sh_mobile_lcdcfb.c
+++ b/drivers/video/fbdev/sh_mobile_lcdcfb.c
@@ -2140,17 +2140,10 @@ static int sh_mobile_lcdc_get_brightness(struct backlight_device *bdev)
 	return ch->bl_brightness;
 }
 
-static int sh_mobile_lcdc_check_fb(struct backlight_device *bdev,
-				   struct fb_info *info)
-{
-	return (info->bl_dev == bdev);
-}
-
 static const struct backlight_ops sh_mobile_lcdc_bl_ops = {
 	.options	= BL_CORE_SUSPENDRESUME,
 	.update_status	= sh_mobile_lcdc_update_bl,
 	.get_brightness	= sh_mobile_lcdc_get_brightness,
-	.check_fb	= sh_mobile_lcdc_check_fb,
 };
 
 static struct backlight_device *sh_mobile_lcdc_bl_probe(struct device *parent,
-- 
2.43.0

[PATCH v2 08/10] fbdev/ssd1307fb: Init backlight before registering framebuffer

[Thomas Zimmermann]

For drivers that support backlight, LCD and fbdev devices, fbdev has
to be initialized last. See documentation for struct fbinfo.bl_dev.

The backlight name's index number comes from register_framebuffer(),
which now happens after initializing the backlight device. So like
in all other backlight drivers, we now give the backlight device a
generic name without the fbdev index.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
---
 drivers/video/fbdev/ssd1307fb.c | 24 +++++++++++-------------
 1 file changed, 11 insertions(+), 13 deletions(-)

diff --git a/drivers/video/fbdev/ssd1307fb.c b/drivers/video/fbdev/ssd1307fb.c
index 1a4f90ea7d5a8..0d1590c61eb06 100644
--- a/drivers/video/fbdev/ssd1307fb.c
+++ b/drivers/video/fbdev/ssd1307fb.c
@@ -594,7 +594,6 @@ static int ssd1307fb_probe(struct i2c_client *client)
 {
 	struct device *dev = &client->dev;
 	struct backlight_device *bl;
-	char bl_name[12];
 	struct fb_info *info;
 	struct fb_deferred_io *ssd1307fb_defio;
 	u32 vmem_size;
@@ -733,31 +732,30 @@ static int ssd1307fb_probe(struct i2c_client *client)
 	if (ret)
 		goto regulator_enable_error;
 
-	ret = register_framebuffer(info);
-	if (ret) {
-		dev_err(dev, "Couldn't register the framebuffer\n");
-		goto panel_init_error;
-	}
-
-	snprintf(bl_name, sizeof(bl_name), "ssd1307fb%d", info->node);
-	bl = backlight_device_register(bl_name, dev, par, &ssd1307fb_bl_ops,
+	bl = backlight_device_register("ssd1307fb-bl", dev, par, &ssd1307fb_bl_ops,
 				       NULL);
 	if (IS_ERR(bl)) {
 		ret = PTR_ERR(bl);
 		dev_err(dev, "unable to register backlight device: %d\n", ret);
-		goto bl_init_error;
+		goto panel_init_error;
+	}
+	info->bl_dev = bl;
+
+	ret = register_framebuffer(info);
+	if (ret) {
+		dev_err(dev, "Couldn't register the framebuffer\n");
+		goto fb_init_error;
 	}
 
 	bl->props.brightness = par->contrast;
 	bl->props.max_brightness = MAX_CONTRAST;
-	info->bl_dev = bl;
 
 	dev_info(dev, "fb%d: %s framebuffer device registered, using %d bytes of video memory\n", info->node, info->fix.id, vmem_size);
 
 	return 0;
 
-bl_init_error:
-	unregister_framebuffer(info);
+fb_init_error:
+	backlight_device_unregister(bl);
 panel_init_error:
 	pwm_disable(par->pwm);
 	pwm_put(par->pwm);
-- 
2.43.0

[PATCH v2 09/10] fbdev/ssd1307fb: Remove struct backlight_ops.check_fb

[Thomas Zimmermann]

The driver sets struct fb_info.bl_dev to the correct backlight
device. Thus rely on the backlight core code to match backlight
and framebuffer devices, and remove the extra check_fb function
from struct backlight_ops.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
---
 drivers/video/fbdev/ssd1307fb.c | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/drivers/video/fbdev/ssd1307fb.c b/drivers/video/fbdev/ssd1307fb.c
index 0d1590c61eb06..3f30af3c059e0 100644
--- a/drivers/video/fbdev/ssd1307fb.c
+++ b/drivers/video/fbdev/ssd1307fb.c
@@ -530,17 +530,10 @@ static int ssd1307fb_get_brightness(struct backlight_device *bdev)
 	return par->contrast;
 }
 
-static int ssd1307fb_check_fb(struct backlight_device *bdev,
-				   struct fb_info *info)
-{
-	return (info->bl_dev == bdev);
-}
-
 static const struct backlight_ops ssd1307fb_bl_ops = {
 	.options	= BL_CORE_SUSPENDRESUME,
 	.update_status	= ssd1307fb_update_bl,
 	.get_brightness	= ssd1307fb_get_brightness,
-	.check_fb	= ssd1307fb_check_fb,
 };
 
 static struct ssd1307fb_deviceinfo ssd1307fb_ssd1305_deviceinfo = {
-- 
2.43.0

[PATCH v2 10/10] backlight: Add controls_device callback to struct backlight_ops

[Thomas Zimmermann]

Replace check_fb with controls_device in struct backlight_ops. The
new callback interface takes a Linux device instead of a framebuffer.
Resolves one of the dependencies of backlight.h on fb.h.

The few drivers that had custom implementations of check_fb can easily
use the framebuffer's Linux device instead. Update them accordingly.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
---
 drivers/video/backlight/backlight.c      |  2 +-
 drivers/video/backlight/bd6107.c         | 12 ++++++------
 drivers/video/backlight/gpio_backlight.c | 12 ++++++------
 drivers/video/backlight/lv5207lp.c       | 12 ++++++------
 include/linux/backlight.h                | 16 ++++++++--------
 5 files changed, 27 insertions(+), 27 deletions(-)

diff --git a/drivers/video/backlight/backlight.c b/drivers/video/backlight/backlight.c
index 48844a4f28ad3..18a0ac4bd6005 100644
--- a/drivers/video/backlight/backlight.c
+++ b/drivers/video/backlight/backlight.c
@@ -111,7 +111,7 @@ static int fb_notifier_callback(struct notifier_block *self,
 
 	if (!bd->ops)
 		goto out;
-	else if (bd->ops->check_fb && !bd->ops->check_fb(bd, info))
+	else if (bd->ops->controls_device && !bd->ops->controls_device(bd, info->device))
 		goto out;
 #if IS_ENABLED(CONFIG_FB_BACKLIGHT)
 	else if (info->bl_dev && info->bl_dev != bd)
diff --git a/drivers/video/backlight/bd6107.c b/drivers/video/backlight/bd6107.c
index c95a12bf0ce26..d124ede084ef9 100644
--- a/drivers/video/backlight/bd6107.c
+++ b/drivers/video/backlight/bd6107.c
@@ -99,18 +99,18 @@ static int bd6107_backlight_update_status(struct backlight_device *backlight)
 	return 0;
 }
 
-static int bd6107_backlight_check_fb(struct backlight_device *backlight,
-				       struct fb_info *info)
+static bool bd6107_backlight_controls_device(struct backlight_device *backlight,
+					     struct device *display_dev)
 {
 	struct bd6107 *bd = bl_get_data(backlight);
 
-	return !bd->pdata->dev || bd->pdata->dev == info->device;
+	return !bd->pdata->dev || bd->pdata->dev == display_dev;
 }
 
 static const struct backlight_ops bd6107_backlight_ops = {
-	.options	= BL_CORE_SUSPENDRESUME,
-	.update_status	= bd6107_backlight_update_status,
-	.check_fb	= bd6107_backlight_check_fb,
+	.options	 = BL_CORE_SUSPENDRESUME,
+	.update_status	 = bd6107_backlight_update_status,
+	.controls_device = bd6107_backlight_controls_device,
 };
 
 static int bd6107_probe(struct i2c_client *client)
diff --git a/drivers/video/backlight/gpio_backlight.c b/drivers/video/backlight/gpio_backlight.c
index d28c30b2a35d2..c0cff685ea848 100644
--- a/drivers/video/backlight/gpio_backlight.c
+++ b/drivers/video/backlight/gpio_backlight.c
@@ -30,18 +30,18 @@ static int gpio_backlight_update_status(struct backlight_device *bl)
 	return 0;
 }
 
-static int gpio_backlight_check_fb(struct backlight_device *bl,
-				   struct fb_info *info)
+static bool gpio_backlight_controls_device(struct backlight_device *bl,
+					   struct device *display_dev)
 {
 	struct gpio_backlight *gbl = bl_get_data(bl);
 
-	return !gbl->dev || gbl->dev == info->device;
+	return !gbl->dev || gbl->dev == display_dev;
 }
 
 static const struct backlight_ops gpio_backlight_ops = {
-	.options	= BL_CORE_SUSPENDRESUME,
-	.update_status	= gpio_backlight_update_status,
-	.check_fb	= gpio_backlight_check_fb,
+	.options	 = BL_CORE_SUSPENDRESUME,
+	.update_status	 = gpio_backlight_update_status,
+	.controls_device = gpio_backlight_controls_device,
 };
 
 static int gpio_backlight_probe(struct platform_device *pdev)
diff --git a/drivers/video/backlight/lv5207lp.c b/drivers/video/backlight/lv5207lp.c
index 1f1d06b4e119a..0cf00fee0f605 100644
--- a/drivers/video/backlight/lv5207lp.c
+++ b/drivers/video/backlight/lv5207lp.c
@@ -62,18 +62,18 @@ static int lv5207lp_backlight_update_status(struct backlight_device *backlight)
 	return 0;
 }
 
-static int lv5207lp_backlight_check_fb(struct backlight_device *backlight,
-				       struct fb_info *info)
+static bool lv5207lp_backlight_controls_device(struct backlight_device *backlight,
+					       struct device *display_dev)
 {
 	struct lv5207lp *lv = bl_get_data(backlight);
 
-	return !lv->pdata->dev || lv->pdata->dev == info->device;
+	return !lv->pdata->dev || lv->pdata->dev == display_dev;
 }
 
 static const struct backlight_ops lv5207lp_backlight_ops = {
-	.options	= BL_CORE_SUSPENDRESUME,
-	.update_status	= lv5207lp_backlight_update_status,
-	.check_fb	= lv5207lp_backlight_check_fb,
+	.options	 = BL_CORE_SUSPENDRESUME,
+	.update_status	 = lv5207lp_backlight_update_status,
+	.controls_device = lv5207lp_backlight_controls_device,
 };
 
 static int lv5207lp_probe(struct i2c_client *client)
diff --git a/include/linux/backlight.h b/include/linux/backlight.h
index 614653e07e3a8..2db4c70053c46 100644
--- a/include/linux/backlight.h
+++ b/include/linux/backlight.h
@@ -13,6 +13,7 @@
 #include <linux/fb.h>
 #include <linux/mutex.h>
 #include <linux/notifier.h>
+#include <linux/types.h>
 
 /**
  * enum backlight_update_reason - what method was used to update backlight
@@ -110,7 +111,6 @@ enum backlight_scale {
 };
 
 struct backlight_device;
-struct fb_info;
 
 /**
  * struct backlight_ops - backlight operations
@@ -160,18 +160,18 @@ struct backlight_ops {
 	int (*get_brightness)(struct backlight_device *);
 
 	/**
-	 * @check_fb: Check the framebuffer device.
+	 * @controls_device: Check against the display device
 	 *
-	 * Check if given framebuffer device is the one bound to this backlight.
-	 * This operation is optional and if not implemented it is assumed that the
-	 * fbdev is always the one bound to the backlight.
+	 * Check if the backlight controls the given display device. This
+	 * operation is optional and if not implemented it is assumed that
+	 * the display is always the one controlled by the backlight.
 	 *
 	 * RETURNS:
 	 *
-	 * If info is NULL or the info matches the fbdev bound to the backlight return true.
-	 * If info does not match the fbdev bound to the backlight return false.
+	 * If display_dev is NULL or display_dev matches the device controlled by
+	 * the backlight, return true. Otherwise return false.
 	 */
-	int (*check_fb)(struct backlight_device *bd, struct fb_info *info);
+	bool (*controls_device)(struct backlight_device *bd, struct device *display_dev);
 };
 
 /**
-- 
2.43.0