[PATCH 2/4] drm/bridge: dw-hdmi: add cec notifier support

From: hverkuil@xs4all.nl (Hans Verkuil)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 2/4] drm/bridge: dw-hdmi: add cec notifier support
Date: Fri, 9 Jun 2017 16:04:20 +0200	[thread overview]
Message-ID: <34525119-5700-76fc-fcf4-5d90bd674b77@xs4all.nl> (raw)
In-Reply-To: <5b2fdadd-f1fa-c454-b3fe-facf221beb78@baylibre.com>

On 09/06/17 15:56, Neil Armstrong wrote:
> On 06/09/2017 03:38 PM, Russell King - ARM Linux wrote:
>> On Fri, Jun 09, 2017 at 02:59:20PM +0200, Neil Armstrong wrote:
>>> On 05/30/2017 04:23 PM, Russell King wrote:
>>>> Add CEC notifier support to the HDMI bridge driver, so that the CEC
>>>> part of the IP can receive its physical address.
>>>>
>>>> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
>>>> ---
>>>>  drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 22 +++++++++++++++++++++-
>>>>  1 file changed, 21 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
>>>> index 4e1f54a675d8..966422576c44 100644
>>>> --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
>>>> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
>>>> @@ -36,7 +36,10 @@
>>>>  #include "dw-hdmi.h"
>>>>  #include "dw-hdmi-audio.h"
>>>>  
>>>> +#include <media/cec-notifier.h>
>>>> +
>>>>  #define DDC_SEGMENT_ADDR	0x30
>>>> +
>>>>  #define HDMI_EDID_LEN		512
>>>>  
>>>>  enum hdmi_datamap {
>>>> @@ -173,6 +176,8 @@ struct dw_hdmi {
>>>>  
>>>>  	unsigned int reg_shift;
>>>>  	struct regmap *regm;
>>>> +
>>>> +	struct cec_notifier *cec_notifier;
>>>>  };
>>>>  
>>>>  #define HDMI_IH_PHY_STAT0_RX_SENSE \
>>>> @@ -1870,6 +1875,7 @@ static int dw_hdmi_connector_get_modes(struct drm_connector *connector)
>>>>  		hdmi->sink_is_hdmi = drm_detect_hdmi_monitor(edid);
>>>>  		hdmi->sink_has_audio = drm_detect_monitor_audio(edid);
>>>>  		drm_mode_connector_update_edid_property(connector, edid);
>>>> +		cec_notifier_set_phys_addr_from_edid(hdmi->cec_notifier, edid);
>>>>  		ret = drm_add_edid_modes(connector, edid);
>>>>  		/* Store the ELD */
>>>>  		drm_edid_to_eld(connector, edid);
>>>> @@ -2108,11 +2114,16 @@ static irqreturn_t dw_hdmi_irq(int irq, void *dev_id)
>>>>  	 * ask the source to re-read the EDID.
>>>>  	 */
>>>>  	if (intr_stat &
>>>> -	    (HDMI_IH_PHY_STAT0_RX_SENSE | HDMI_IH_PHY_STAT0_HPD))
>>>> +	    (HDMI_IH_PHY_STAT0_RX_SENSE | HDMI_IH_PHY_STAT0_HPD)) {
>>>>  		__dw_hdmi_setup_rx_sense(hdmi,
>>>>  					 phy_stat & HDMI_PHY_HPD,
>>>>  					 phy_stat & HDMI_PHY_RX_SENSE);
>>>>  
>>>> +		if ((phy_stat & (HDMI_PHY_RX_SENSE | HDMI_PHY_HPD)) == 0)
>>>> +			cec_notifier_set_phys_addr(hdmi->cec_notifier,
>>>> +						   CEC_PHYS_ADDR_INVALID);
>>>> +	}
>>>> +
>>>>  	if (intr_stat & HDMI_IH_PHY_STAT0_HPD) {
>>>>  		dev_dbg(hdmi->dev, "EVENT=%s\n",
>>>>  			phy_int_pol & HDMI_PHY_HPD ? "plugin" : "plugout");
>>>> @@ -2365,6 +2376,12 @@ __dw_hdmi_probe(struct platform_device *pdev,
>>>>  	if (ret)
>>>>  		goto err_iahb;
>>>>  
>>>> +	hdmi->cec_notifier = cec_notifier_get(dev);
>>>> +	if (!hdmi->cec_notifier) {
>>>> +		ret = -ENOMEM;
>>>> +		goto err_iahb;
>>>> +	}
>>>> +
>>>>  	/*
>>>>  	 * To prevent overflows in HDMI_IH_FC_STAT2, set the clk regenerator
>>>>  	 * N and cts values before enabling phy
>>>> @@ -2437,6 +2454,9 @@ __dw_hdmi_probe(struct platform_device *pdev,
>>>>  		hdmi->ddc = NULL;
>>>>  	}
>>>>  
>>>> +	if (hdmi->cec_notifier)
>>>> +		cec_notifier_put(hdmi->cec_notifier);
>>>> +
>>>>  	clk_disable_unprepare(hdmi->iahb_clk);
>>>>  err_isfr:
>>>>  	clk_disable_unprepare(hdmi->isfr_clk);
>>>>
>>>
>>> Hi Archit,
>>>
>>> I think this one could go through drm-next since it's quite
>>> standalone and will reduce the DW-HDMI CEC patchset and dependencies.
>>
>> Not a good idea.  If you read all the comments, Hans is suggesting that
>> CEC should be part of dw-hdmi itself, not stand-alone.  That would mean
>> this patch probably changes - basically, with CEC support built-in to
>> dw-hdmi, we don't need the notifier stuff.
> 
> Hi Russell,
> 
> Yes, but on the Amlogic Meson plarform, the DW-HDMI CEC controller is not used,
> but a custom one, so this notifier is actually useful for this platform and
> maybe others.
> 
>>
>> So, I'd suggest _not_ merging it at the moment, because the patch could
>> well become obsolete.
> 
> It won't since the Meson platform needs it...

Ah, I wasn't aware of that when I wrote my original comments. In that case
we do need the notifier. Which is fine, as long as the reason for that is
documented.

> 
>>
>> Wait until the CEC changes that Hans has talked about have hit mainline
>> and I've had a chance to rework this for those.  We're waiting on Mauro
>> for that at the moment.
>>
>> (I do find it rather frustrating that CEC seems to evolve very rapidly,
>> it makes it quite difficult to publish a patch set, and get it merged.)
>>
> 
> Should we really wait until I push the Amlogic AO CEC driver ? Having a
> notifier in the DW-HDMI driver won't harm anybody since it *will be used*.

I'm OK with the notifier in this case.

Regards,

	Hans