| Message ID | 20201210134648.272857-7-maxime@cerno.tech (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/vc4: hdmi: Add CEC support for the BCM2711 | expand |
Hi Maxime On Thu, 10 Dec 2020 at 13:47, Maxime Ripard <maxime@cerno.tech> wrote: > > 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@cerno.tech> Reviewed-by: Dave Stevenson <dave.stevenson@raspberrypi.com> (To be a total pedant it's still a fixed frequency on vc4, but it's configurable via the variant entry). > --- > 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 >
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,
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@cerno.tech> --- drivers/gpu/drm/vc4/vc4_hdmi.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)