From 32b3911a79b0ede875d7f5ea11695e29141a1088 Mon Sep 17 00:00:00 2001
From: Maxime Ripard <maxime@cerno.tech>
Date: Fri, 25 Feb 2022 15:35:33 +0100
Subject: drm/vc4: Add logging and comments
Git-commit: 5b6ef06ea6225570bc0b33325306c7b8c6bdf5eb
Patch-mainline: v5.19-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225

The HVS core clock isn't really obvious, so let's add a bunch more
comments and some logging for easier debugging.

Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://lore.kernel.org/r/20220225143534.405820-12-maxime@cerno.tech
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/vc4/vc4_kms.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/gpu/drm/vc4/vc4_kms.c b/drivers/gpu/drm/vc4/vc4_kms.c
index bffd81d4bfcf..4d01697a77b1 100644
--- a/drivers/gpu/drm/vc4/vc4_kms.c
+++ b/drivers/gpu/drm/vc4/vc4_kms.c
@@ -390,8 +390,15 @@ static void vc4_atomic_commit_tail(struct drm_atomic_state *state)
 						500000000,
 						new_hvs_state->core_clock_rate);
 
+		drm_dbg(dev, "Raising the core clock at %lu Hz\n", core_rate);
+
+		/*
+		 * Do a temporary request on the core clock during the
+		 * modeset.
+		 */
 		clk_set_min_rate(hvs->core_clk, core_rate);
 	}
+
 	drm_atomic_helper_commit_modeset_disables(dev, state);
 
 	vc4_ctm_commit(vc4, state);
@@ -417,6 +424,10 @@ static void vc4_atomic_commit_tail(struct drm_atomic_state *state)
 		drm_dbg(dev, "Running the core clock at %lu Hz\n",
 			new_hvs_state->core_clock_rate);
 
+		/*
+		 * Request a clock rate based on the current HVS
+		 * requirements.
+		 */
 		clk_set_min_rate(hvs->core_clk, new_hvs_state->core_clock_rate);
 	}
 }
-- 
2.38.1