Commit 072ed343 authored by Douglas Anderson's avatar Douglas Anderson
Browse files

drm/dp: Move panel DP AUX backlight support to drm_dp_helper 



We were getting a depmod error:
  depmod: ERROR: Cycle detected: drm_kms_helper -> drm -> drm_kms_helper

It looks like the rule is that drm_kms_helper can call into drm, but
drm can't call into drm_kms_helper. That means we've got to move the
DP AUX backlight support into drm_dp_helper.

NOTE: as part of this, I didn't try to do any renames of the main
registration function. Even though it's in the drm_dp_helper, it still
feels very parallel to drm_panel_of_backlight().

Fixes: 10f7b40e ("drm/panel: add basic DP AUX backlight support")
Reported-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Reported-by: default avatarThomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: default avatarDouglas Anderson <dianders@chromium.org>
Reviewed-by: default avatarRajeev Nandan <rajeevny@codeaurora.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210712075933.v2.1.I23eb4cc5a680341e7b3e791632a635566fa5806a@changeid
parent bbeb7461

drivers/gpu/drm/drm_dp_helper.c

+113 −0
Original line number Diff line number Diff line
@@ -33,9 +33,17 @@ 
#include <drm/drm_print.h>

#include <drm/drm_vblank.h>

#include <drm/drm_dp_mst_helper.h>

#include <drm/drm_panel.h>



#include "drm_crtc_helper_internal.h"



struct dp_aux_backlight {

	struct backlight_device *base;

	struct drm_dp_aux *aux;

	struct drm_edp_backlight_info info;

	bool enabled;

};



/**

 * DOC: dp helpers

 *
@@ -3462,3 +3470,108 @@ drm_edp_backlight_init(struct drm_dp_aux *aux, struct drm_edp_backlight_info *bl 
	return 0;

}

EXPORT_SYMBOL(drm_edp_backlight_init);



#if IS_BUILTIN(CONFIG_BACKLIGHT_CLASS_DEVICE) || \

	(IS_MODULE(CONFIG_DRM_KMS_HELPER) && IS_MODULE(CONFIG_BACKLIGHT_CLASS_DEVICE))



static int dp_aux_backlight_update_status(struct backlight_device *bd)

{

	struct dp_aux_backlight *bl = bl_get_data(bd);

	u16 brightness = backlight_get_brightness(bd);

	int ret = 0;



	if (!backlight_is_blank(bd)) {

		if (!bl->enabled) {

			drm_edp_backlight_enable(bl->aux, &bl->info, brightness);

			bl->enabled = true;

			return 0;

		}

		ret = drm_edp_backlight_set_level(bl->aux, &bl->info, brightness);

	} else {

		if (bl->enabled) {

			drm_edp_backlight_disable(bl->aux, &bl->info);

			bl->enabled = false;

		}

	}



	return ret;

}



static const struct backlight_ops dp_aux_bl_ops = {

	.update_status = dp_aux_backlight_update_status,

};



/**

 * drm_panel_dp_aux_backlight - create and use DP AUX backlight

 * @panel: DRM panel

 * @aux: The DP AUX channel to use

 *

 * Use this function to create and handle backlight if your panel

 * supports backlight control over DP AUX channel using DPCD

 * registers as per VESA's standard backlight control interface.

 *

 * When the panel is enabled backlight will be enabled after a

 * successful call to &drm_panel_funcs.enable()

 *

 * When the panel is disabled backlight will be disabled before the

 * call to &drm_panel_funcs.disable().

 *

 * A typical implementation for a panel driver supporting backlight

 * control over DP AUX will call this function at probe time.

 * Backlight will then be handled transparently without requiring

 * any intervention from the driver.

 *

 * drm_panel_dp_aux_backlight() must be called after the call to drm_panel_init().

 *

 * Return: 0 on success or a negative error code on failure.

 */

int drm_panel_dp_aux_backlight(struct drm_panel *panel, struct drm_dp_aux *aux)

{

	struct dp_aux_backlight *bl;

	struct backlight_properties props = { 0 };

	u16 current_level;

	u8 current_mode;

	u8 edp_dpcd[EDP_DISPLAY_CTL_CAP_SIZE];

	int ret;



	if (!panel || !panel->dev || !aux)

		return -EINVAL;



	ret = drm_dp_dpcd_read(aux, DP_EDP_DPCD_REV, edp_dpcd,

			       EDP_DISPLAY_CTL_CAP_SIZE);

	if (ret < 0)

		return ret;



	if (!drm_edp_backlight_supported(edp_dpcd)) {

		DRM_DEV_INFO(panel->dev, "DP AUX backlight is not supported\n");

		return 0;

	}



	bl = devm_kzalloc(panel->dev, sizeof(*bl), GFP_KERNEL);

	if (!bl)

		return -ENOMEM;



	bl->aux = aux;



	ret = drm_edp_backlight_init(aux, &bl->info, 0, edp_dpcd,

				     &current_level, &current_mode);

	if (ret < 0)

		return ret;



	props.type = BACKLIGHT_RAW;

	props.brightness = current_level;

	props.max_brightness = bl->info.max;



	bl->base = devm_backlight_device_register(panel->dev, "dp_aux_backlight",

						  panel->dev, bl,

						  &dp_aux_bl_ops, &props);

	if (IS_ERR(bl->base))

		return PTR_ERR(bl->base);



	panel->backlight = bl->base;



	return 0;

}

EXPORT_SYMBOL(drm_panel_dp_aux_backlight);



#endif

drivers/gpu/drm/drm_panel.c

+0 −108
Original line number Diff line number Diff line
@@ -26,20 +26,12 @@ 
#include <linux/module.h>



#include <drm/drm_crtc.h>

#include <drm/drm_dp_helper.h>

#include <drm/drm_panel.h>

#include <drm/drm_print.h>



static DEFINE_MUTEX(panel_lock);

static LIST_HEAD(panel_list);



struct dp_aux_backlight {

	struct backlight_device *base;

	struct drm_dp_aux *aux;

	struct drm_edp_backlight_info info;

	bool enabled;

};



/**

 * DOC: drm panel

 *
@@ -350,106 +342,6 @@ int drm_panel_of_backlight(struct drm_panel *panel) 
	return 0;

}

EXPORT_SYMBOL(drm_panel_of_backlight);



static int dp_aux_backlight_update_status(struct backlight_device *bd)

{

	struct dp_aux_backlight *bl = bl_get_data(bd);

	u16 brightness = backlight_get_brightness(bd);

	int ret = 0;



	if (!backlight_is_blank(bd)) {

		if (!bl->enabled) {

			drm_edp_backlight_enable(bl->aux, &bl->info, brightness);

			bl->enabled = true;

			return 0;

		}

		ret = drm_edp_backlight_set_level(bl->aux, &bl->info, brightness);

	} else {

		if (bl->enabled) {

			drm_edp_backlight_disable(bl->aux, &bl->info);

			bl->enabled = false;

		}

	}



	return ret;

}



static const struct backlight_ops dp_aux_bl_ops = {

	.update_status = dp_aux_backlight_update_status,

};



/**

 * drm_panel_dp_aux_backlight - create and use DP AUX backlight

 * @panel: DRM panel

 * @aux: The DP AUX channel to use

 *

 * Use this function to create and handle backlight if your panel

 * supports backlight control over DP AUX channel using DPCD

 * registers as per VESA's standard backlight control interface.

 *

 * When the panel is enabled backlight will be enabled after a

 * successful call to &drm_panel_funcs.enable()

 *

 * When the panel is disabled backlight will be disabled before the

 * call to &drm_panel_funcs.disable().

 *

 * A typical implementation for a panel driver supporting backlight

 * control over DP AUX will call this function at probe time.

 * Backlight will then be handled transparently without requiring

 * any intervention from the driver.

 *

 * drm_panel_dp_aux_backlight() must be called after the call to drm_panel_init().

 *

 * Return: 0 on success or a negative error code on failure.

 */

int drm_panel_dp_aux_backlight(struct drm_panel *panel, struct drm_dp_aux *aux)

{

	struct dp_aux_backlight *bl;

	struct backlight_properties props = { 0 };

	u16 current_level;

	u8 current_mode;

	u8 edp_dpcd[EDP_DISPLAY_CTL_CAP_SIZE];

	int ret;



	if (!panel || !panel->dev || !aux)

		return -EINVAL;



	ret = drm_dp_dpcd_read(aux, DP_EDP_DPCD_REV, edp_dpcd,

			       EDP_DISPLAY_CTL_CAP_SIZE);

	if (ret < 0)

		return ret;



	if (!drm_edp_backlight_supported(edp_dpcd)) {

		DRM_DEV_INFO(panel->dev, "DP AUX backlight is not supported\n");

		return 0;

	}



	bl = devm_kzalloc(panel->dev, sizeof(*bl), GFP_KERNEL);

	if (!bl)

		return -ENOMEM;



	bl->aux = aux;



	ret = drm_edp_backlight_init(aux, &bl->info, 0, edp_dpcd,

				     &current_level, &current_mode);

	if (ret < 0)

		return ret;



	props.type = BACKLIGHT_RAW;

	props.brightness = current_level;

	props.max_brightness = bl->info.max;



	bl->base = devm_backlight_device_register(panel->dev, "dp_aux_backlight",

						  panel->dev, bl,

						  &dp_aux_bl_ops, &props);

	if (IS_ERR(bl->base))

		return PTR_ERR(bl->base);



	panel->backlight = bl->base;



	return 0;

}

EXPORT_SYMBOL(drm_panel_dp_aux_backlight);

#endif



MODULE_AUTHOR("Thierry Reding <treding@nvidia.com>");

include/drm/drm_dp_helper.h

+16 −0
Original line number Diff line number Diff line
@@ -30,6 +30,7 @@ 


struct drm_device;

struct drm_dp_aux;

struct drm_panel;



/*

 * Unless otherwise noted, all values are from the DP 1.1a spec.  Note that
@@ -2200,6 +2201,21 @@ int drm_edp_backlight_enable(struct drm_dp_aux *aux, const struct drm_edp_backli 
			     u16 level);

int drm_edp_backlight_disable(struct drm_dp_aux *aux, const struct drm_edp_backlight_info *bl);



#if IS_ENABLED(CONFIG_DRM_KMS_HELPER) && (IS_BUILTIN(CONFIG_BACKLIGHT_CLASS_DEVICE) || \

	(IS_MODULE(CONFIG_DRM_KMS_HELPER) && IS_MODULE(CONFIG_BACKLIGHT_CLASS_DEVICE)))



int drm_panel_dp_aux_backlight(struct drm_panel *panel, struct drm_dp_aux *aux);



#else



static inline int drm_panel_dp_aux_backlight(struct drm_panel *panel,

					     struct drm_dp_aux *aux)

{

	return 0;

}



#endif



#ifdef CONFIG_DRM_DP_CEC

void drm_dp_cec_irq(struct drm_dp_aux *aux);

void drm_dp_cec_register_connector(struct drm_dp_aux *aux,

include/drm/drm_panel.h

+0 −8
Original line number Diff line number Diff line
@@ -32,7 +32,6 @@ struct backlight_device; 
struct device_node;

struct drm_connector;

struct drm_device;

struct drm_dp_aux;

struct drm_panel;

struct display_timing;
@@ -209,18 +208,11 @@ static inline int of_drm_get_panel_orientation(const struct device_node *np, 
#if IS_ENABLED(CONFIG_DRM_PANEL) && (IS_BUILTIN(CONFIG_BACKLIGHT_CLASS_DEVICE) || \

	(IS_MODULE(CONFIG_DRM) && IS_MODULE(CONFIG_BACKLIGHT_CLASS_DEVICE)))

int drm_panel_of_backlight(struct drm_panel *panel);

int drm_panel_dp_aux_backlight(struct drm_panel *panel, struct drm_dp_aux *aux);

#else

static inline int drm_panel_of_backlight(struct drm_panel *panel)

{

	return 0;

}



static inline int drm_panel_dp_aux_backlight(struct drm_panel *panel,

					     struct drm_dp_aux *aux)

{

	return 0;

}

#endif



#endif