drm/simpledrm: Make backlight support a Kconfig option

And make it mutually exclusive with DCP.

Signed-off-by: Hector Martin <marcan@marcan.st>

Author: marcan

drivers/gpu/drm/tiny/Kconfig

@@ -97,6 +97,13 @@ config DRM_SIMPLEDRM
 	  On x86 BIOS or UEFI systems, you should also select SYSFB_SIMPLEFB
 	  to use UEFI and VESA framebuffers.
 
+config DRM_SIMPLEDRM_BACKLIGHT
+	bool "Backlight support for simpledrm"
+	depends on DRM_SIMPLEDRM && !DRM_APPLE
+	select BACKLIGHT_CLASS_DEVICE
+	help
+	  Enable backlight support for simpledrm.
+
 config TINYDRM_HX8357D
 	tristate "DRM support for HX8357D display panels"
 	depends on DRM && SPI

drivers/gpu/drm/tiny/simpledrm.c

@@ -1,6 +1,8 @@
 // SPDX-License-Identifier: GPL-2.0-only
 
+#if defined CONFIG_DRM_SIMPLEDRM_BACKLIGHT
 #include <linux/backlight.h>
+#endif
 #include <linux/clk.h>
 #include <linux/of_clk.h>
 #include <linux/minmax.h>
@@ -244,8 +246,10 @@ struct simpledrm_device {
 	struct drm_crtc crtc;
 	struct drm_encoder encoder;
 	struct drm_connector connector;
+#if defined CONFIG_DRM_SIMPLEDRM_BACKLIGHT
 	/* backlight */
 	struct backlight_device *backlight;
+#endif
 };
 
 static struct simpledrm_device *simpledrm_device_of_dev(struct drm_device *dev)
@@ -556,6 +560,7 @@ static enum drm_mode_status simpledrm_crtc_helper_mode_valid(struct drm_crtc *cr
 	return drm_crtc_helper_mode_valid_fixed(crtc, mode, &sdev->mode);
 }
 
+#if defined CONFIG_DRM_SIMPLEDRM_BACKLIGHT
 static void simpledrm_crtc_helper_atomic_enable(struct drm_crtc *crtc,
 						struct drm_atomic_state *state)
 {
@@ -575,6 +580,7 @@ static void simpledrm_crtc_helper_atomic_disable(struct drm_crtc *crtc,
 	if (sdev->backlight)
 		backlight_disable(sdev->backlight);
 }
+#endif
 
 /*
  * The CRTC is always enabled. Screen updates are performed by
@@ -584,8 +590,10 @@ static void simpledrm_crtc_helper_atomic_disable(struct drm_crtc *crtc,
 static const struct drm_crtc_helper_funcs simpledrm_crtc_helper_funcs = {
 	.mode_valid = simpledrm_crtc_helper_mode_valid,
 	.atomic_check = drm_crtc_helper_atomic_check,
+#if defined CONFIG_DRM_SIMPLEDRM_BACKLIGHT
 	.atomic_enable = simpledrm_crtc_helper_atomic_enable,
 	.atomic_disable = simpledrm_crtc_helper_atomic_disable,
+#endif
 };
 
 static const struct drm_crtc_funcs simpledrm_crtc_funcs = {
@@ -674,10 +682,11 @@ static struct simpledrm_device *simpledrm_device_create(struct drm_driver *drv,
 	 * Hardware settings
 	 */
 
+#if defined CONFIG_DRM_SIMPLEDRM_BACKLIGHT
 	sdev->backlight = devm_of_find_backlight(&pdev->dev);
 	if (IS_ERR(sdev->backlight))
 		sdev->backlight = NULL;
-
+#endif
 	ret = simpledrm_device_init_clocks(sdev);
 	if (ret)
 		return ERR_PTR(ret);