[PATCH 5.11 277/775] drm/vc4: hdmi: Compute the CEC clock divider from the clock rate
From: Greg Kroah-Hartman
Date: Mon Mar 01 2021 - 19:58:21 EST
From: Maxime Ripard <maxime@xxxxxxxxxx>
[ Upstream commit 163a3ef681e5e9d5df558e855d86ccd4708d6200 ]
The CEC clock divider needs to output a frequency of 40kHz from the HSM
rate on the BCM2835. The driver used to have a fixed frequency for it,
but that changed for the BCM2711 and we now need to compute it
dynamically to maintain the proper rate.
Fixes: cd4cb49dc5bb ("drm/vc4: hdmi: Adjust HSM clock rate depending on pixel rate")
Reviewed-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
Signed-off-by: Maxime Ripard <maxime@xxxxxxxxxx>
Acked-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
Tested-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20210111142309.193441-7-maxime@xxxxxxxxxx
(cherry picked from commit f1ceb9d10043683b89e5e5e5848fb4e855295762)
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/gpu/drm/vc4/vc4_hdmi.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
index a9a6552bdae93..eff9014750e2d 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -1467,6 +1467,7 @@ static int vc4_hdmi_cec_init(struct vc4_hdmi *vc4_hdmi)
{
struct cec_connector_info conn_info;
struct platform_device *pdev = vc4_hdmi->pdev;
+ u16 clk_cnt;
u32 value;
int ret;
@@ -1492,8 +1493,9 @@ static int vc4_hdmi_cec_init(struct vc4_hdmi *vc4_hdmi)
* divider: the hsm_clock rate and this divider setting will
* give a 40 kHz CEC clock.
*/
+ clk_cnt = clk_get_rate(vc4_hdmi->hsm_clock) / CEC_CLOCK_FREQ;
value |= VC4_HDMI_CEC_ADDR_MASK |
- (4091 << VC4_HDMI_CEC_DIV_CLK_CNT_SHIFT);
+ (clk_cnt << VC4_HDMI_CEC_DIV_CLK_CNT_SHIFT);
HDMI_WRITE(HDMI_CEC_CNTRL_1, value);
ret = devm_request_threaded_irq(&pdev->dev, platform_get_irq(pdev, 0),
vc4_cec_irq_handler,
--
2.27.0