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Subject[PATCH v5 75/80] drm/vc4: hdmi: Add pixel BVB clock control
Date
From: Hoegeun Kwon <hoegeun.kwon@samsung.com>

The BCM2711 has another clock that needs to be ramped up depending on the
pixel rate: the pixel BVB clock. Add the code to adjust that clock when
changing the mode.

Signed-off-by: Hoegeun Kwon <hoegeun.kwon@samsung.com>
[Maxime: Changed the commit log, used clk_set_min_rate]
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20200901040759.29992-3-hoegeun.kwon@samsung.com
---
drivers/gpu/drm/vc4/vc4_hdmi.c | 23 +++++++++++++++++++++++
drivers/gpu/drm/vc4/vc4_hdmi.h | 1 +
2 files changed, 24 insertions(+)

diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
index ab7abb409de2..39508107dafd 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -54,6 +54,7 @@
#include "vc4_regs.h"

#define CEC_CLOCK_FREQ 40000
+#define VC4_HSM_MID_CLOCK 149985000

static int vc4_hdmi_debugfs_regs(struct seq_file *m, void *unused)
{
@@ -344,6 +345,7 @@ static void vc4_hdmi_encoder_post_crtc_powerdown(struct drm_encoder *encoder)
HDMI_WRITE(HDMI_VID_CTL,
HDMI_READ(HDMI_VID_CTL) & ~VC4_HD_VID_CTL_ENABLE);

+ clk_disable_unprepare(vc4_hdmi->pixel_bvb_clock);
clk_disable_unprepare(vc4_hdmi->hsm_clock);
clk_disable_unprepare(vc4_hdmi->pixel_clock);

@@ -516,6 +518,27 @@ static void vc4_hdmi_encoder_pre_crtc_configure(struct drm_encoder *encoder)
return;
}

+ /*
+ * FIXME: When the pixel freq is 594MHz (4k60), this needs to be setup
+ * at 150MHz.
+ */
+ ret = clk_set_min_rate(vc4_hdmi->pixel_bvb_clock,
+ (hsm_rate > VC4_HSM_MID_CLOCK ? 150000000 : 75000000));
+ if (ret) {
+ DRM_ERROR("Failed to set pixel bvb clock rate: %d\n", ret);
+ clk_disable_unprepare(vc4_hdmi->hsm_clock);
+ clk_disable_unprepare(vc4_hdmi->pixel_clock);
+ return;
+ }
+
+ ret = clk_prepare_enable(vc4_hdmi->pixel_bvb_clock);
+ if (ret) {
+ DRM_ERROR("Failed to turn on pixel bvb clock: %d\n", ret);
+ clk_disable_unprepare(vc4_hdmi->hsm_clock);
+ clk_disable_unprepare(vc4_hdmi->pixel_clock);
+ return;
+ }
+
if (vc4_hdmi->variant->reset)
vc4_hdmi->variant->reset(vc4_hdmi);

diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.h b/drivers/gpu/drm/vc4/vc4_hdmi.h
index 34138e0dd4a6..59639b405b7f 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.h
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.h
@@ -119,6 +119,7 @@ struct vc4_hdmi {
struct clk *pixel_clock;
struct clk *hsm_clock;
struct clk *audio_clock;
+ struct clk *pixel_bvb_clock;

struct debugfs_regset32 hdmi_regset;
struct debugfs_regset32 hd_regset;
--
git-series 0.9.1
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