openwrt/target/linux/bcm27xx/patches-5.10/950-0574-drm-vc4-hdmi-Properly-compute-the-BVB-clock-rate.patch

From acc8ac41d15594d4f735531c89bbeb03d85c344d Mon Sep 17 00:00:00 2001
From: Maxime Ripard <maxime@cerno.tech>
Date: Thu, 8 Oct 2020 16:06:08 +0200
Subject: [PATCH] drm/vc4: hdmi: Properly compute the BVB clock rate

The BVB clock rate computation doesn't take into account a mode clock of
594MHz that we're going to need to support 4k60.

Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
---
 drivers/gpu/drm/vc4/vc4_hdmi.c | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -93,7 +93,6 @@
 
 #define HSM_MIN_CLOCK_FREQ	120000000
 #define CEC_CLOCK_FREQ 40000
-#define VC4_HSM_MID_CLOCK 149985000
 
 static int vc4_hdmi_debugfs_regs(struct seq_file *m, void *unused)
 {
@@ -814,7 +813,7 @@ static void vc4_hdmi_encoder_pre_crtc_co
 		conn_state_to_vc4_hdmi_conn_state(conn_state);
 	struct drm_display_mode *mode = &encoder->crtc->state->adjusted_mode;
 	struct vc4_hdmi *vc4_hdmi = encoder_to_vc4_hdmi(encoder);
-	unsigned long pixel_rate, hsm_rate;
+	unsigned long bvb_rate, pixel_rate, hsm_rate;
 	int ret;
 
 	ret = pm_runtime_resume_and_get(&vc4_hdmi->pdev->dev);
@@ -863,12 +862,14 @@ static void vc4_hdmi_encoder_pre_crtc_co
 
 	vc4_hdmi_cec_update_clk_div(vc4_hdmi);
 
-	/*
-	 * FIXME: When the pixel freq is 594MHz (4k60), this needs to be setup
-	 * at 300MHz.
-	 */
-	vc4_hdmi->bvb_req = clk_request_start(vc4_hdmi->pixel_bvb_clock,
-					      (hsm_rate > VC4_HSM_MID_CLOCK ? 150000000 : 75000000));
+	if (pixel_rate > 297000000)
+		bvb_rate = 300000000;
+	else if (pixel_rate > 148500000)
+		bvb_rate = 150000000;
+	else
+		bvb_rate = 75000000;
+
+	vc4_hdmi->bvb_req = clk_request_start(vc4_hdmi->pixel_bvb_clock, bvb_rate);
 	if (IS_ERR(vc4_hdmi->bvb_req)) {
 		DRM_ERROR("Failed to set pixel bvb clock rate: %ld\n", PTR_ERR(vc4_hdmi->bvb_req));
 		clk_request_done(vc4_hdmi->hsm_req);