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SubjectRe: [PATCH 1/2] drm/bridge/synopsys: dw-hdmi: Add an option to suppress loading CEC driver


Le 25/03/2019 02:35, Laurent Pinchart a écrit :
> Hi Jernej,
>
> Thank you for the patch.
>
> On Sun, Mar 24, 2019 at 10:21:42PM +0100, Jernej Skrabec wrote:
>> DW HDMI controller on some Allwinner SoCs has support for CEC, but due
>> to additional logic put between CEC controller and pins, it doesn't work
>> correctly, at least not with a lot of instrusive changes. Fortunately,
>> it's still possible to bitbang protocol.
>>
>> For such cases, add a platform option to suppress loading CEC driver. If
>> DW HDMI CEC driver would be loaded, it wouldn't work anyway and only
>> cause a confusion with multiple /dev entries.
>>
>> Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
>> ---
>> 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 a63e5f0dae56..fdda26f8b056 100644
>> --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
>> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
>> @@ -2634,7 +2634,7 @@ __dw_hdmi_probe(struct platform_device *pdev,
>> hdmi->audio = platform_device_register_full(&pdevinfo);
>> }
>>
>> - if (config0 & HDMI_CONFIG0_CEC) {
>> + if (!plat_data->is_cec_unusable && (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 66e70770cce5..764b8bcfa62c 100644
>> --- a/include/drm/bridge/dw_hdmi.h
>> +++ b/include/drm/bridge/dw_hdmi.h
>> @@ -144,6 +144,8 @@ struct dw_hdmi_plat_data {
>> int (*configure_phy)(struct dw_hdmi *hdmi,
>> const struct dw_hdmi_plat_data *pdata,
>> unsigned long mpixelclock);
>> +
>> + unsigned int is_cec_unusable : 1;
>
> Strictly speaking your CEC controller isn't unusable, it's just a bit
> difficult to use it according to your commit message. Would disable_cec
> be a more appropriate field name ?

Actually, it would be useful to have in for Amlogic SoCs also, the dw-hdmi
is configured with the CEC engine, but isn't connected to an external I/O.
And we have easy way to disable it unless disabling the DW-HDMI CEC driver...
With a more appropriate name,
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>

> And how difficult would it be to
> support the hardware CEC controller, would that result in changes that
> could be useful to other vendors too ?
>
>> };
>>
>> struct dw_hdmi *dw_hdmi_probe(struct platform_device *pdev,
>

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