[PATCH v2 06/15] drm/vc4: hdmi: Compute the CEC clock divider from the clock rate
From: Maxime Ripard <hidden>
Date: 2021-01-11 14:26:10
Also in:
dri-devel, linux-media, lkml
Subsystem:
drm drivers, drm drivers and misc gpu patches, drm drivers for vc4, the rest · Maintainers:
David Airlie, Simona Vetter, Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann, Dave Stevenson, Linus Torvalds
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@raspberrypi.com>
Signed-off-by: Maxime Ripard <redacted>
---
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 c3a301396aad..50008513edfc 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c@@ -1598,6 +1598,7 @@ 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;
@@ -1623,8 +1624,9 @@ 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,
--
2.29.2
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel