This adds DW-HDMI driver a glue option to disable loading of the CEC sub-driver.
On some SoCs, the CEC functionality is enabled in the IP config bits, but the CEC bus is non-functional like on Amlogic SoCs, where the CEC config bit is set but the DW-HDMI CEC signal is not connected to a physical pin, leading to some confusion when the DW-HDMI CEC controller can't communicate on the bus.
Jernej Skrabec (1): drm/bridge/synopsys: dw-hdmi: Add an option to suppress loading CEC driver
Neil Armstrong (1): drm/meson: dw-hdmi: disable DW-HDMI CEC sub-driver
drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 2 +- drivers/gpu/drm/meson/meson_dw_hdmi.c | 1 + include/drm/bridge/dw_hdmi.h | 2 ++ 3 files changed, 4 insertions(+), 1 deletion(-)
From: Jernej Skrabec jernej.skrabec@siol.net
This adds DW-HDMI driver a glue option to disable loading of the CEC sub-driver.
On some SoCs, the CEC functionality is enabled in the IP config bits, but the CEC bus is non-functional like on Amlogic SoCs, where the CEC config bit is set but the DW-HDMI CEC signal is not connected to a physical pin, leading to some confusion when the DW-HDMI CEC controller can't communicate on the bus.
Reviewed-by: Neil Armstrong narmstrong@baylibre.com Signed-off-by: Jernej Skrabec jernej.skrabec@siol.net Signed-off-by: Neil Armstrong narmstrong@baylibre.com --- drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 2 +- include/drm/bridge/dw_hdmi.h | 2 ++ 2 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c index dda4fa9a1a08..ae97513ef886 100644 --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c @@ -3421,7 +3421,7 @@ struct dw_hdmi *dw_hdmi_probe(struct platform_device *pdev, hdmi->audio = platform_device_register_full(&pdevinfo); }
- if (config0 & HDMI_CONFIG0_CEC) { + if (!plat_data->disable_cec && (config0 & HDMI_CONFIG0_CEC)) { cec.hdmi = hdmi; cec.ops = &dw_hdmi_cec_ops; cec.irq = irq; diff --git a/include/drm/bridge/dw_hdmi.h b/include/drm/bridge/dw_hdmi.h index ea34ca146b82..6a5716655619 100644 --- a/include/drm/bridge/dw_hdmi.h +++ b/include/drm/bridge/dw_hdmi.h @@ -153,6 +153,8 @@ struct dw_hdmi_plat_data { const struct dw_hdmi_phy_config *phy_config; int (*configure_phy)(struct dw_hdmi *hdmi, void *data, unsigned long mpixelclock); + + unsigned int disable_cec : 1; };
struct dw_hdmi *dw_hdmi_probe(struct platform_device *pdev,
On the Amlogic SoCs, the DW-HDMI HW support is here but the DW-HDMI CEC signal is not connected to a physical pin, leading to confusion when the dw-hdmi cec controller can't communicate on the bus.
Disable it to avoid exposing a non-functinal bus.
Signed-off-by: Neil Armstrong narmstrong@baylibre.com --- drivers/gpu/drm/meson/meson_dw_hdmi.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/drivers/gpu/drm/meson/meson_dw_hdmi.c b/drivers/gpu/drm/meson/meson_dw_hdmi.c index aad75a22dc33..2ed87cfdd735 100644 --- a/drivers/gpu/drm/meson/meson_dw_hdmi.c +++ b/drivers/gpu/drm/meson/meson_dw_hdmi.c @@ -1103,6 +1103,7 @@ static int meson_dw_hdmi_bind(struct device *dev, struct device *master, dw_plat_data->phy_data = meson_dw_hdmi; dw_plat_data->input_bus_encoding = V4L2_YCBCR_ENC_709; dw_plat_data->ycbcr_420_allowed = true; + dw_plat_data->disable_cec = true;
if (dw_hdmi_is_compatible(meson_dw_hdmi, "amlogic,meson-gxl-dw-hdmi") || dw_hdmi_is_compatible(meson_dw_hdmi, "amlogic,meson-gxm-dw-hdmi") ||
Hi Neil,
On Fri, Apr 16, 2021 at 11:27:35AM +0200, Neil Armstrong wrote:
This adds DW-HDMI driver a glue option to disable loading of the CEC sub-driver.
On some SoCs, the CEC functionality is enabled in the IP config bits, but the CEC bus is non-functional like on Amlogic SoCs, where the CEC config bit is set but the DW-HDMI CEC signal is not connected to a physical pin, leading to some confusion when the DW-HDMI CEC controller can't communicate on the bus.
If we can't trust the CEC config bit, would it be better to not use it at all, and instead let each platform glue logic tell whether to enable CEC or not ?
Jernej Skrabec (1): drm/bridge/synopsys: dw-hdmi: Add an option to suppress loading CEC driver
Neil Armstrong (1): drm/meson: dw-hdmi: disable DW-HDMI CEC sub-driver
drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 2 +- drivers/gpu/drm/meson/meson_dw_hdmi.c | 1 + include/drm/bridge/dw_hdmi.h | 2 ++ 3 files changed, 4 insertions(+), 1 deletion(-)
On 16/04/2021 11:58, Laurent Pinchart wrote:
Hi Neil,
On Fri, Apr 16, 2021 at 11:27:35AM +0200, Neil Armstrong wrote:
This adds DW-HDMI driver a glue option to disable loading of the CEC sub-driver.
On some SoCs, the CEC functionality is enabled in the IP config bits, but the CEC bus is non-functional like on Amlogic SoCs, where the CEC config bit is set but the DW-HDMI CEC signal is not connected to a physical pin, leading to some confusion when the DW-HDMI CEC controller can't communicate on the bus.
If we can't trust the CEC config bit, would it be better to not use it at all, and instead let each platform glue logic tell whether to enable CEC or not ?
Actually, the CEC config bit is right, the HW exists and should be functional, but this bit doesn't tell if the CEC signal is connected to something.
This lies in the IP integration, like other bits under the "amlogic,meson-*-dw-hdmi" umbrella.
The first attempt was by Hans using DT, but adding a property in DT for a vendor specific compatible doesn't make sense. Another idea would be to describe the CEC signal endpoint like we do for video signal, but I think this is out of scope and this solution is much simpler and straightforward, and it's more an exception than a general use case to solve.
Neil
Jernej Skrabec (1): drm/bridge/synopsys: dw-hdmi: Add an option to suppress loading CEC driver
Neil Armstrong (1): drm/meson: dw-hdmi: disable DW-HDMI CEC sub-driver
drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 2 +- drivers/gpu/drm/meson/meson_dw_hdmi.c | 1 + include/drm/bridge/dw_hdmi.h | 2 ++ 3 files changed, 4 insertions(+), 1 deletion(-)
CC Hans Verkuil
Dne petek, 16. april 2021 ob 13:38:59 CEST je Neil Armstrong napisal(a):
On 16/04/2021 11:58, Laurent Pinchart wrote:
Hi Neil,
On Fri, Apr 16, 2021 at 11:27:35AM +0200, Neil Armstrong wrote:
This adds DW-HDMI driver a glue option to disable loading of the CEC sub-driver.
On some SoCs, the CEC functionality is enabled in the IP config bits, but the CEC bus is non-functional like on Amlogic SoCs, where the CEC config bit is set but the DW-HDMI CEC signal is not connected to a physical pin, leading to some confusion when the DW-HDMI CEC controller can't communicate on the bus.>
If we can't trust the CEC config bit, would it be better to not use it at all, and instead let each platform glue logic tell whether to enable CEC or not ?
Actually, the CEC config bit is right, the HW exists and should be functional, but this bit doesn't tell if the CEC signal is connected to something.
I'm in favour of Neil's solution. Currently we have only one exception.
This lies in the IP integration, like other bits under the "amlogic,meson-*-dw-hdmi" umbrella.
The first attempt was by Hans using DT, but adding a property in DT for a vendor specific compatible doesn't make sense. Another idea would be to describe the CEC signal endpoint like we do for video signal, but I think this is out of scope and this solution is much simpler and straightforward, and it's more an exception than a general use case to solve.
Note that we still need DT property for disabling CEC. I have one Allwinner H3 board where board designer decided to use GPIO CEC implementation instead of DW HDMI one (vendor Linux doesn't implement DW HDMI CEC driver). Other H3 boards happily use DW HDMI CEC.
Best regards, Jernej
Neil
Jernej Skrabec (1): drm/bridge/synopsys: dw-hdmi: Add an option to suppress loading CEC
driverNeil Armstrong (1): drm/meson: dw-hdmi: disable DW-HDMI CEC sub-driver
drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 2 +- drivers/gpu/drm/meson/meson_dw_hdmi.c | 1 + include/drm/bridge/dw_hdmi.h | 2 ++ 3 files changed, 4 insertions(+), 1 deletion(-)
On 16/04/2021 13:38, Neil Armstrong wrote:
On 16/04/2021 11:58, Laurent Pinchart wrote:
Hi Neil,
On Fri, Apr 16, 2021 at 11:27:35AM +0200, Neil Armstrong wrote:
This adds DW-HDMI driver a glue option to disable loading of the CEC sub-driver.
On some SoCs, the CEC functionality is enabled in the IP config bits, but the CEC bus is non-functional like on Amlogic SoCs, where the CEC config bit is set but the DW-HDMI CEC signal is not connected to a physical pin, leading to some confusion when the DW-HDMI CEC controller can't communicate on the bus.
If we can't trust the CEC config bit, would it be better to not use it at all, and instead let each platform glue logic tell whether to enable CEC or not ?
Actually, the CEC config bit is right, the HW exists and should be functional, but this bit doesn't tell if the CEC signal is connected to something.
This lies in the IP integration, like other bits under the "amlogic,meson-*-dw-hdmi" umbrella.
The first attempt was by Hans using DT, but adding a property in DT for a vendor specific compatible doesn't make sense. Another idea would be to describe the CEC signal endpoint like we do for video signal, but I think this is out of scope and this solution is much simpler and straightforward, and it's more an exception than a general use case to solve.
While a DT property might not make sense in this particular case, I still believe that it is a perfectly valid approach in general: whether or not the CEC pin is connected is at the hardware level decision, it is not something that software can detect. If the designer of the board didn't connect it, then the only place you can define that is in the device tree.
Anyway, for meson I am fine with this solution. At least it prevents creating a non-functioning cec device. So for this series:
Acked-by: Hans Verkuil hverkuil-cisco@xs4all.nl
Regards,
Hans
Neil
Jernej Skrabec (1): drm/bridge/synopsys: dw-hdmi: Add an option to suppress loading CEC driver
Neil Armstrong (1): drm/meson: dw-hdmi: disable DW-HDMI CEC sub-driver
drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 2 +- drivers/gpu/drm/meson/meson_dw_hdmi.c | 1 + include/drm/bridge/dw_hdmi.h | 2 ++ 3 files changed, 4 insertions(+), 1 deletion(-)
dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
On 20/04/2021 17:13, Hans Verkuil wrote:
On 16/04/2021 13:38, Neil Armstrong wrote:
On 16/04/2021 11:58, Laurent Pinchart wrote:
Hi Neil,
On Fri, Apr 16, 2021 at 11:27:35AM +0200, Neil Armstrong wrote:
This adds DW-HDMI driver a glue option to disable loading of the CEC sub-driver.
On some SoCs, the CEC functionality is enabled in the IP config bits, but the CEC bus is non-functional like on Amlogic SoCs, where the CEC config bit is set but the DW-HDMI CEC signal is not connected to a physical pin, leading to some confusion when the DW-HDMI CEC controller can't communicate on the bus.
If we can't trust the CEC config bit, would it be better to not use it at all, and instead let each platform glue logic tell whether to enable CEC or not ?
Actually, the CEC config bit is right, the HW exists and should be functional, but this bit doesn't tell if the CEC signal is connected to something.
This lies in the IP integration, like other bits under the "amlogic,meson-*-dw-hdmi" umbrella.
The first attempt was by Hans using DT, but adding a property in DT for a vendor specific compatible doesn't make sense. Another idea would be to describe the CEC signal endpoint like we do for video signal, but I think this is out of scope and this solution is much simpler and straightforward, and it's more an exception than a general use case to solve.
While a DT property might not make sense in this particular case, I still believe that it is a perfectly valid approach in general: whether or not the CEC pin is connected is at the hardware level decision, it is not something that software can detect. If the designer of the board didn't connect it, then the only place you can define that is in the device tree.
Agreed, we need to define a smart way to declare CEC bus relationship in DT, the side effect would be to handle this particular case.
Anyway, for meson I am fine with this solution. At least it prevents creating a non-functioning cec device. So for this series:
Acked-by: Hans Verkuil hverkuil-cisco@xs4all.nl
Thanks,
Applying this serie to drm-misc-next
Neil
Regards,
Hans
Neil
Jernej Skrabec (1): drm/bridge/synopsys: dw-hdmi: Add an option to suppress loading CEC driver
Neil Armstrong (1): drm/meson: dw-hdmi: disable DW-HDMI CEC sub-driver
drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 2 +- drivers/gpu/drm/meson/meson_dw_hdmi.c | 1 + include/drm/bridge/dw_hdmi.h | 2 ++ 3 files changed, 4 insertions(+), 1 deletion(-)
dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
On Tue, Apr 20, 2021 at 05:19:52PM +0200, Neil Armstrong wrote:
On 20/04/2021 17:13, Hans Verkuil wrote:
On 16/04/2021 13:38, Neil Armstrong wrote:
On 16/04/2021 11:58, Laurent Pinchart wrote:
Hi Neil,
On Fri, Apr 16, 2021 at 11:27:35AM +0200, Neil Armstrong wrote:
This adds DW-HDMI driver a glue option to disable loading of the CEC sub-driver.
On some SoCs, the CEC functionality is enabled in the IP config bits, but the CEC bus is non-functional like on Amlogic SoCs, where the CEC config bit is set but the DW-HDMI CEC signal is not connected to a physical pin, leading to some confusion when the DW-HDMI CEC controller can't communicate on the bus.
If we can't trust the CEC config bit, would it be better to not use it at all, and instead let each platform glue logic tell whether to enable CEC or not ?
Actually, the CEC config bit is right, the HW exists and should be functional, but this bit doesn't tell if the CEC signal is connected to something.
This lies in the IP integration, like other bits under the "amlogic,meson-*-dw-hdmi" umbrella.
The first attempt was by Hans using DT, but adding a property in DT for a vendor specific compatible doesn't make sense. Another idea would be to describe the CEC signal endpoint like we do for video signal, but I think this is out of scope and this solution is much simpler and straightforward, and it's more an exception than a general use case to solve.
While a DT property might not make sense in this particular case, I still believe that it is a perfectly valid approach in general: whether or not the CEC pin is connected is at the hardware level decision, it is not something that software can detect. If the designer of the board didn't connect it, then the only place you can define that is in the device tree.
Agreed, we need to define a smart way to declare CEC bus relationship in DT, the side effect would be to handle this particular case.
I wonder if it would make sense to use the OF graph bindings to describe the connection between the CEC controller and the CEC "device" (which I assume in most cases will be a DT node for a physical connector). Or is this overkill ?
Anyway, for meson I am fine with this solution. At least it prevents creating a non-functioning cec device. So for this series:
Acked-by: Hans Verkuil hverkuil-cisco@xs4all.nl
Thanks,
Applying this serie to drm-misc-next
Jernej Skrabec (1): drm/bridge/synopsys: dw-hdmi: Add an option to suppress loading CEC driver
Neil Armstrong (1): drm/meson: dw-hdmi: disable DW-HDMI CEC sub-driver
drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 2 +- drivers/gpu/drm/meson/meson_dw_hdmi.c | 1 + include/drm/bridge/dw_hdmi.h | 2 ++ 3 files changed, 4 insertions(+), 1 deletion(-)
dri-devel@lists.freedesktop.org
-
Hans Verkuil -
Jernej Škrabec -
Laurent Pinchart -
Neil Armstrong