From 80f9eb70fd9276938f0a131f76d438021bfd8b34 Mon Sep 17 00:00:00 2001
From: Geert Uytterhoeven <geert@linux-m68k.org>
Date: Tue, 19 Oct 2021 16:45:08 +0200
Subject: [PATCH] auxdisplay: ht16k33: Connect backlight to fbdev
Git-commit: 80f9eb70fd9276938f0a131f76d438021bfd8b34
Patch-mainline: v5.16-rc1
References: git-fixes stable-5.14.19

Currently /sys/class/graphics/fb0/bl_curve is not accessible (-ENODEV),
as the driver does not connect the backlight to the frame buffer device.
Fix this moving backlight initialization up, and filling in
fb_info.bl_dev.

Fixes: 8992da44c6805d53 ("auxdisplay: ht16k33: Driver for LED controller")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Robin van der Gracht <robin@protonic.nl>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/auxdisplay/ht16k33.c | 56 ++++++++++++++++++------------------
 1 file changed, 28 insertions(+), 28 deletions(-)

diff --git a/drivers/auxdisplay/ht16k33.c b/drivers/auxdisplay/ht16k33.c
index 1e69cc6d21a0..2b630e194570 100644
--- a/drivers/auxdisplay/ht16k33.c
+++ b/drivers/auxdisplay/ht16k33.c
@@ -413,6 +413,33 @@ static int ht16k33_probe(struct i2c_client *client,
 	if (err)
 		return err;
 
+	/* Backlight */
+	memset(&bl_props, 0, sizeof(struct backlight_properties));
+	bl_props.type = BACKLIGHT_RAW;
+	bl_props.max_brightness = MAX_BRIGHTNESS;
+
+	bl = devm_backlight_device_register(&client->dev, DRIVER_NAME"-bl",
+					    &client->dev, priv,
+					    &ht16k33_bl_ops, &bl_props);
+	if (IS_ERR(bl)) {
+		dev_err(&client->dev, "failed to register backlight\n");
+		return PTR_ERR(bl);
+	}
+
+	err = of_property_read_u32(node, "default-brightness-level",
+				   &dft_brightness);
+	if (err) {
+		dft_brightness = MAX_BRIGHTNESS;
+	} else if (dft_brightness > MAX_BRIGHTNESS) {
+		dev_warn(&client->dev,
+			 "invalid default brightness level: %u, using %u\n",
+			 dft_brightness, MAX_BRIGHTNESS);
+		dft_brightness = MAX_BRIGHTNESS;
+	}
+
+	bl->props.brightness = dft_brightness;
+	ht16k33_bl_update_status(bl);
+
 	/* Framebuffer (2 bytes per column) */
 	BUILD_BUG_ON(PAGE_SIZE < HT16K33_FB_SIZE);
 	fbdev->buffer = (unsigned char *) get_zeroed_page(GFP_KERNEL);
@@ -445,6 +472,7 @@ static int ht16k33_probe(struct i2c_client *client,
 	fbdev->info->screen_size = HT16K33_FB_SIZE;
 	fbdev->info->fix = ht16k33_fb_fix;
 	fbdev->info->var = ht16k33_fb_var;
+	fbdev->info->bl_dev = bl;
 	fbdev->info->pseudo_palette = NULL;
 	fbdev->info->flags = FBINFO_FLAG_DEFAULT;
 	fbdev->info->par = priv;
@@ -460,34 +488,6 @@ static int ht16k33_probe(struct i2c_client *client,
 			goto err_fbdev_unregister;
 	}
 
-	/* Backlight */
-	memset(&bl_props, 0, sizeof(struct backlight_properties));
-	bl_props.type = BACKLIGHT_RAW;
-	bl_props.max_brightness = MAX_BRIGHTNESS;
-
-	bl = devm_backlight_device_register(&client->dev, DRIVER_NAME"-bl",
-					    &client->dev, priv,
-					    &ht16k33_bl_ops, &bl_props);
-	if (IS_ERR(bl)) {
-		dev_err(&client->dev, "failed to register backlight\n");
-		err = PTR_ERR(bl);
-		goto err_fbdev_unregister;
-	}
-
-	err = of_property_read_u32(node, "default-brightness-level",
-				   &dft_brightness);
-	if (err) {
-		dft_brightness = MAX_BRIGHTNESS;
-	} else if (dft_brightness > MAX_BRIGHTNESS) {
-		dev_warn(&client->dev,
-			 "invalid default brightness level: %u, using %u\n",
-			 dft_brightness, MAX_BRIGHTNESS);
-		dft_brightness = MAX_BRIGHTNESS;
-	}
-
-	bl->props.brightness = dft_brightness;
-	ht16k33_bl_update_status(bl);
-
 	ht16k33_fb_queue(priv);
 	return 0;
 
-- 
2.26.2