drm/amd/display: make all backlight calls link based

[Why]
Backlight adjustment is tied to a specific display.  So make the calls
target a link rather than making it a global state.

[How]
make all backlight calls link based
Signed-off-by: Anthony Koo <Anthony.Koo@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c

@@ -1228,8 +1228,9 @@ static int current_backlight_read(struct seq_file *m, void *data)
 	struct drm_info_node *node = (struct drm_info_node *)m->private;
 	struct drm_device *dev = node->minor->dev;
 	struct amdgpu_device *adev = dev->dev_private;
-	struct dc *dc = adev->dm.dc;
-	unsigned int backlight = dc_get_current_backlight_pwm(dc);
+	struct amdgpu_display_manager *dm = &adev->dm;
+
+	unsigned int backlight = dc_link_get_backlight_level(dm->backlight_link);
 
 	seq_printf(m, "0x%x\n", backlight);
 	return 0;
@@ -1245,8 +1246,9 @@ static int target_backlight_read(struct seq_file *m, void *data)
 	struct drm_info_node *node = (struct drm_info_node *)m->private;
 	struct drm_device *dev = node->minor->dev;
 	struct amdgpu_device *adev = dev->dev_private;
-	struct dc *dc = adev->dm.dc;
-	unsigned int backlight = dc_get_target_backlight_pwm(dc);
+	struct amdgpu_display_manager *dm = &adev->dm;
+
+	unsigned int backlight = dc_link_get_target_backlight_pwm(dm->backlight_link);
 
 	seq_printf(m, "0x%x\n", backlight);
 	return 0;

drivers/gpu/drm/amd/display/dc/core/dc.c

@@ -2646,33 +2646,12 @@ void dc_set_power_state(
 
 void dc_resume(struct dc *dc)
 {
-
 	uint32_t i;
 
 	for (i = 0; i < dc->link_count; i++)
 		core_link_resume(dc->links[i]);
 }
 
-unsigned int dc_get_current_backlight_pwm(struct dc *dc)
-{
-	struct abm *abm = dc->res_pool->abm;
-
-	if (abm)
-		return abm->funcs->get_current_backlight(abm);
-
-	return 0;
-}
-
-unsigned int dc_get_target_backlight_pwm(struct dc *dc)
-{
-	struct abm *abm = dc->res_pool->abm;
-
-	if (abm)
-		return abm->funcs->get_target_backlight(abm);
-
-	return 0;
-}
-
 bool dc_is_dmcu_initialized(struct dc *dc)
 {
 	struct dmcu *dmcu = dc->res_pool->dmcu;

drivers/gpu/drm/amd/display/dc/core/dc_link.c

@@ -2450,6 +2450,16 @@ int dc_link_get_backlight_level(const struct dc_link *link)
 	return (int) abm->funcs->get_current_backlight(abm);
 }
 
+int dc_link_get_target_backlight_pwm(const struct dc_link *link)
+{
+	struct abm *abm = link->ctx->dc->res_pool->abm;
+
+	if (abm == NULL || abm->funcs->get_target_backlight == NULL)
+		return DC_ERROR_UNEXPECTED;
+
+	return (int) abm->funcs->get_target_backlight(abm);
+}
+
 bool dc_link_set_backlight_level(const struct dc_link *link,
 		uint32_t backlight_pwm_u16_16,
 		uint32_t frame_ramp)
@@ -2507,14 +2517,24 @@ bool dc_link_set_backlight_level(const struct dc_link *link,
 bool dc_link_set_abm_disable(const struct dc_link *link)
 {
 	struct dc  *dc = link->ctx->dc;
-	struct abm *abm = dc->res_pool->abm;
+	struct abm *abm = NULL;
+	bool success = false;
+	int i;
 
-	if ((abm == NULL) || (abm->funcs->set_backlight_level_pwm == NULL))
-		return false;
+	for (i = 0; i < MAX_PIPES; i++) {
+		struct pipe_ctx pipe_ctx = dc->current_state->res_ctx.pipe_ctx[i];
+		struct dc_stream_state *stream = pipe_ctx.stream;
+
+		if (stream && stream->link == link) {
+			abm = pipe_ctx.stream_res.abm;
+			break;
+		}
+	}
 
-	abm->funcs->set_abm_immediate_disable(abm);
+	if (abm)
+		success = abm->funcs->set_abm_immediate_disable(abm);
 
-	return true;
+	return success;
 }
 
 bool dc_link_set_psr_allow_active(struct dc_link *link, bool allow_active, bool wait)

drivers/gpu/drm/amd/display/dc/dc.h

@@ -1139,8 +1139,6 @@ void dc_set_power_state(
 		struct dc *dc,
 		enum dc_acpi_cm_power_state power_state);
 void dc_resume(struct dc *dc);
-unsigned int dc_get_current_backlight_pwm(struct dc *dc);
-unsigned int dc_get_target_backlight_pwm(struct dc *dc);
 
 #if defined(CONFIG_DRM_AMD_DC_HDCP)
 /*

drivers/gpu/drm/amd/display/dc/dc_link.h

@@ -217,6 +217,8 @@ bool dc_link_set_default_brightness_aux(struct dc_link *link);
 
 int dc_link_get_backlight_level(const struct dc_link *dc_link);
 
+int dc_link_get_target_backlight_pwm(const struct dc_link *link);
+
 bool dc_link_set_abm_disable(const struct dc_link *dc_link);
 
 bool dc_link_set_psr_allow_active(struct dc_link *dc_link, bool enable, bool wait);