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 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")
Signed-off-by: Maxime Ripard <maxime@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 eff3bac562c6..0c53d7427d15 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -1586,6 +1586,7 @@ 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;
@@ -1611,8 +1612,9 @@ 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,
--
2.28.0
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