Re: [PATCH 4/4] drm/bridge: dw-hdmi: add cec driver

2017-06-12 Thread Hans Verkuil 

On 06/01/2017 10:31 AM, Hans Verkuil wrote:

Hi Russell,

First a few top-level questions:

1) What was the reason for using the cec-notifier here? Isn't this
tightly integrated into the main dw-hdmi block? For the tda driver
it is clearly required, but for tightly coupled HDMI & CEC HW I
just create the adapter from the HDMI driver. As a small bonus it
avoids adding the cec-notifier code and the control flow is a bit
easier to trace.

2) I may have asked this before, apologies if I repeat myself: does
this CEC implementation support CEC monitoring (aka snooping)? If
it does, then I recommend that it is implemented since it is very
useful.

3) Is the CEC still active if there is no hotplug signal? Or is it
powered off in that case? Ideally it should still be possible to
send CEC messages even if there is no hotplug. This is explicitly
allowed by the CEC 2.0 spec to wake up displays that turn off the
HPD, but that still have a working CEC controller.

If this is not possible, then you need to use the CEC_CAP_NEEDS_HPD
capability. See: https://patchwork.linuxtv.org/patch/41478/

This will almost certainly be merged for 4.13 since other CEC drivers
need this as well.


FYI: I tested your patch series with my cubox-i and CEC doesn't work if there
is no HPD. I fiddles around a bit in dw_hdmi.c to prevent it from powering off
the HDMI and PHY, but without any luck. It could be a hardware issue on the
cubox-i (e.g. a level-shifter that powers off when the HPD goes low, although
I don't see anything like that in the schematics), or it can be a driver issue
or a Synopsys IP issue. I really can't tell.

I added text in my status document 
(https://hverkuil.home.xs4all.nl/cec-status.txt)
at the end on how to test this.

Otherwise the CEC support on the cubox-i was working very well.

Regards,

Hans
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Re: [PATCH 4/4] drm/bridge: dw-hdmi: add cec driver

2017-06-03 Thread Russell King - ARM Linux 
On Fri, Jun 02, 2017 at 11:28:08AM +0200, Hans Verkuil wrote:
> The 'signal_free_time' argument of adap_transmit will have the recommended
> signal free time. You can test against the CEC_SIGNAL_FREE_TIME_* defines
> from media/cec.h. You probably saw this already, but just in case you missed
> this...

Yes, it's a recent addition to the CEC core, which I've added support
for, but it doesn't make too much sense until the retrying stuff is
sorted out.

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Re: [PATCH 4/4] drm/bridge: dw-hdmi: add cec driver

2017-06-03 Thread Russell King - ARM Linux 
On Fri, Jun 02, 2017 at 06:02:28AM +0100, Jose Abreu wrote:
> You should check that CEC is: not in standy, acknowledges
> broadcast messages, signal free time is 5bit period, and not lost
> arbitration, which basically means CEC_CTRL must be 0x2 and
> IH_CEC_STAT0 must not have ARB_LOST set.

If ARB_LOST is set, that will trigger an interrupt, and the interrupt
handler will clear the bit.  So all the time that the interrupt handler
is present, ARB_LOST should be clear whenever we try to send a message.

When we enable the CEC interface, we zero the CEC_CTRL register, which
takes the controller out of standby, and initialises the command
register.

Bits 2:1 select the signal free time, and there's no requirement
specified to require them to be set to '01' before writing the
message - in fact, it's legal for them to be set to other values,
particularly when retrying, which is something I've missed.

 2-1 Frame Type bit
  FRAME_TYP
 00Signal Free Time = 3-bit periods. Previous
   attempt to send frame is unsuccessful.
 01Signal Free Time = 5-bit periods. New initiator
   wants to send a frame.
 10Signal Free Time = 7-bit periods. Present
   initiator wants to send another frame
   immediately after its previous frame. (spec
   CEC 9.1)
 11Illegal value. If software write this value,
   hardware will set the value to the default 2'b01.

Clearly from that, there are times when we want to transmit a message
without a 5-bit signal free time period, particularly when we're
retrying or wanting to send another frame, so I don't believe that
there's a requirement for the control register to always be set to
0x02.  I suspect that where that value is coming from is an application
note describing how to send a brand new message each time, and not
covering the other cases.

It could be that we need to set the frame type before loading the
message - that I'll buy, but not that it must always be set to 0x02.

Provided that the standby and BC_NACK bits are both cleared should
be sufficient.

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Re: [PATCH 4/4] drm/bridge: dw-hdmi: add cec driver

2017-06-03 Thread Russell King - ARM Linux 
On Thu, Jun 01, 2017 at 10:31:10AM +0200, Hans Verkuil wrote:
> This will change. Patches to fix the config handling are pending for 4.12.
> 
> Here you can see the pending patches:
> https://git.linuxtv.org/hverkuil/media_tree.git/log/?h=drm-cec
> 
> The patches from 'cec-notifier.h: handle unreachable CONFIG_CEC_CORE' to
> 'cec: drop MEDIA_CEC_DEBUG' should all be merged in 4.12.

Hi Hans,

I'll wait until these have hit mainline before generating another
patch series.  Do you have any idea when that might happen?

Thanks.

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Re: [PATCH 4/4] drm/bridge: dw-hdmi: add cec driver

2017-06-03 Thread Russell King - ARM Linux 
On Fri, Jun 02, 2017 at 11:06:24AM +0200, Hans Verkuil wrote:
> On 06/02/17 08:43, Jose Abreu wrote:
> > Hi Hans,
> > 
> > 
> > On 02-06-2017 07:31, Hans Verkuil wrote:
> >> On 06/01/2017 03:47 PM, Neil Armstrong wrote:
> >>> On 05/30/2017 04:23 PM, Russell King wrote:
>  Add a CEC driver for the dw-hdmi hardware.
> 
>  Signed-off-by: Russell King 
>  ---
>    drivers/gpu/drm/bridge/synopsys/Kconfig   |   8 +
>    drivers/gpu/drm/bridge/synopsys/Makefile  |   1 +
>    drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c | 320
>  ++
>    drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.h |  19 ++
>    drivers/gpu/drm/bridge/synopsys/dw-hdmi.c |  40 +++-
>    5 files changed, 387 insertions(+), 1 deletion(-)
>    create mode 100644
>  drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c
>    create mode 100644
>  drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.h
> 
>  diff --git a/drivers/gpu/drm/bridge/synopsys/Kconfig
>  b/drivers/gpu/drm/bridge/synopsys/Kconfig
>  index 40d2827a6d19..bd30a0a07272 100644
>  --- a/drivers/gpu/drm/bridge/synopsys/Kconfig
>  +++ b/drivers/gpu/drm/bridge/synopsys/Kconfig
>  @@ -21,3 +21,11 @@ config DRM_DW_HDMI_I2S_AUDIO
>    help
>  Support the I2S Audio interface which is part of the
>  Synopsys
>  Designware HDMI block.
>  +
>  +config DRM_DW_HDMI_CEC
>  +tristate "Synopsis Designware CEC interface"
>  +depends on DRM_DW_HDMI && MEDIA_CEC_SUPPORT
>  +select MEDIA_CEC_NOTIFIER
>  +help
>  +  Support the CE interface which is part of the Synopsis
>  +  Designware HDMI block.
>  diff --git a/drivers/gpu/drm/bridge/synopsys/Makefile
>  b/drivers/gpu/drm/bridge/synopsys/Makefile
>  index 17aa7a65b57e..6fe415903668 100644
>  --- a/drivers/gpu/drm/bridge/synopsys/Makefile
>  +++ b/drivers/gpu/drm/bridge/synopsys/Makefile
>  @@ -3,3 +3,4 @@
>    obj-$(CONFIG_DRM_DW_HDMI) += dw-hdmi.o
>    obj-$(CONFIG_DRM_DW_HDMI_AHB_AUDIO) += dw-hdmi-ahb-audio.o
>    obj-$(CONFIG_DRM_DW_HDMI_I2S_AUDIO) += dw-hdmi-i2s-audio.o
>  +obj-$(CONFIG_DRM_DW_HDMI_CEC) += dw-hdmi-cec.o
>  diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c
>  b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c
>  new file mode 100644
>  index ..761ef5ae687d
>  --- /dev/null
>  +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c
>  @@ -0,0 +1,320 @@
>  +/*
>  + * Designware HDMI CEC driver
>  + *
>  + * Copyright (C) 2015-2017 Russell King.
>  + *
>  + * This program is free software; you can redistribute it
>  and/or modify
>  + * it under the terms of the GNU General Public License
>  version 2 as
>  + * published by the Free Software Foundation.
>  + */
>  +#include 
>  +#include 
>  +#include 
>  +#include 
>  +#include 
>  +#include 
>  +
>  +#include 
>  +
>  +#include 
>  +#include 
>  +
>  +#include "dw-hdmi-cec.h"
>  +
>  +enum {
>  +HDMI_IH_CEC_STAT0= 0x0106,
>  +HDMI_IH_MUTE_CEC_STAT0= 0x0186,
>  +
>  +HDMI_CEC_CTRL= 0x7d00,
>  +CEC_CTRL_START= BIT(0),
>  +CEC_CTRL_NORMAL= 1 << 1,
>  +
>  +HDMI_CEC_STAT= 0x7d01,
>  +CEC_STAT_DONE= BIT(0),
>  +CEC_STAT_EOM= BIT(1),
>  +CEC_STAT_NACK= BIT(2),
>  +CEC_STAT_ARBLOST= BIT(3),
>  +CEC_STAT_ERROR_INIT= BIT(4),
>  +CEC_STAT_ERROR_FOLL= BIT(5),
>  +CEC_STAT_WAKEUP= BIT(6),
> >>
> >> I hadn't realized until Jose Abreu's latest reply, but you need
> >> to check the
> >> ARBLOST status and set the TX state to CEC_TX_STATUS_ARB_LOST.
> >>
> >> I think CEC_STAT_ERROR_FOLL might equal
> >> CEC_TX_STATUS_LOW_DRIVE, but without
> >> documentation I can't be sure.
> >>
> >> My experience is that this low drive condition tends to be
> >> poorly reported by
> >> hardware. Either that or poorly documented. This is why I added a
> >> CEC_TX_STATUS_ERROR status as a catch-all error status when it
> >> is unclear from
> >> the hardware/documentation what error occurred.
> >>
> >> Jose, do you know which status bit is used to report a follower
> >> pulling the
> >> CEC line low for a long time (approx. 3.6 ms) to signal a CEC
> >> error?
> > 
> > Bit 5 for follower error, bit 4 for initiator error.
> 
> I gathered that from the define names :-)
> 
> But what does it mean? What sort of error is reported here?

I think the problem is that no one really knows, the documentation is
quite poor:

 5   An error is notified by a follower. Abnormal logic data
 ERROR_FOLL  bit error (for follower).
 4   An error is detected on cec line (for initiator only).
 ERROR_INIT

It is so vague that

Re: [PATCH 4/4] drm/bridge: dw-hdmi: add cec driver

2017-06-02 Thread Hans Verkuil 
On 06/02/17 14:07, Russell King - ARM Linux wrote:
> On Thu, Jun 01, 2017 at 10:31:10AM +0200, Hans Verkuil wrote:
>> This will change. Patches to fix the config handling are pending for 4.12.
>>
>> Here you can see the pending patches:
>> https://git.linuxtv.org/hverkuil/media_tree.git/log/?h=drm-cec
>>
>> The patches from 'cec-notifier.h: handle unreachable CONFIG_CEC_CORE' to
>> 'cec: drop MEDIA_CEC_DEBUG' should all be merged in 4.12.
> 
> Hi Hans,
> 
> I'll wait until these have hit mainline before generating another
> patch series.  Do you have any idea when that might happen?

rc6? Hard to tell, I know Mauro is very busy so it can be difficult to
predict.

Regards,

Hans
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Re: [PATCH 4/4] drm/bridge: dw-hdmi: add cec driver

2017-06-02 Thread Hans Verkuil 
On 06/02/17 11:15, Russell King - ARM Linux wrote:
> On Fri, Jun 02, 2017 at 06:02:28AM +0100, Jose Abreu wrote:
>> You should check that CEC is: not in standy, acknowledges
>> broadcast messages, signal free time is 5bit period, and not lost
>> arbitration, which basically means CEC_CTRL must be 0x2 and
>> IH_CEC_STAT0 must not have ARB_LOST set.
> 
> If ARB_LOST is set, that will trigger an interrupt, and the interrupt
> handler will clear the bit.  So all the time that the interrupt handler
> is present, ARB_LOST should be clear whenever we try to send a message.
> 
> When we enable the CEC interface, we zero the CEC_CTRL register, which
> takes the controller out of standby, and initialises the command
> register.
> 
> Bits 2:1 select the signal free time, and there's no requirement
> specified to require them to be set to '01' before writing the
> message - in fact, it's legal for them to be set to other values,
> particularly when retrying, which is something I've missed.
> 
>  2-1 Frame Type bit
>   FRAME_TYP
>  00Signal Free Time = 3-bit periods. Previous
>  attempt to send frame is unsuccessful.
>  01Signal Free Time = 5-bit periods. New initiator
>  wants to send a frame.
>  10Signal Free Time = 7-bit periods. Present
>  initiator wants to send another frame
>  immediately after its previous frame. (spec
>  CEC 9.1)
>  11Illegal value. If software write this value,
>  hardware will set the value to the default 2'b01.

The 'signal_free_time' argument of adap_transmit will have the recommended
signal free time. You can test against the CEC_SIGNAL_FREE_TIME_* defines
from media/cec.h. You probably saw this already, but just in case you missed
this...

Regards,

Hans
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Re: [PATCH 4/4] drm/bridge: dw-hdmi: add cec driver

2017-06-02 Thread Hans Verkuil 
On 06/02/17 08:43, Jose Abreu wrote:
> Hi Hans,
> 
> 
> On 02-06-2017 07:31, Hans Verkuil wrote:
>> On 06/01/2017 03:47 PM, Neil Armstrong wrote:
>>> On 05/30/2017 04:23 PM, Russell King wrote:
 Add a CEC driver for the dw-hdmi hardware.

 Signed-off-by: Russell King 
 ---
   drivers/gpu/drm/bridge/synopsys/Kconfig   |   8 +
   drivers/gpu/drm/bridge/synopsys/Makefile  |   1 +
   drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c | 320
 ++
   drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.h |  19 ++
   drivers/gpu/drm/bridge/synopsys/dw-hdmi.c |  40 +++-
   5 files changed, 387 insertions(+), 1 deletion(-)
   create mode 100644
 drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c
   create mode 100644
 drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.h

 diff --git a/drivers/gpu/drm/bridge/synopsys/Kconfig
 b/drivers/gpu/drm/bridge/synopsys/Kconfig
 index 40d2827a6d19..bd30a0a07272 100644
 --- a/drivers/gpu/drm/bridge/synopsys/Kconfig
 +++ b/drivers/gpu/drm/bridge/synopsys/Kconfig
 @@ -21,3 +21,11 @@ config DRM_DW_HDMI_I2S_AUDIO
   help
 Support the I2S Audio interface which is part of the
 Synopsys
 Designware HDMI block.
 +
 +config DRM_DW_HDMI_CEC
 +tristate "Synopsis Designware CEC interface"
 +depends on DRM_DW_HDMI && MEDIA_CEC_SUPPORT
 +select MEDIA_CEC_NOTIFIER
 +help
 +  Support the CE interface which is part of the Synopsis
 +  Designware HDMI block.
 diff --git a/drivers/gpu/drm/bridge/synopsys/Makefile
 b/drivers/gpu/drm/bridge/synopsys/Makefile
 index 17aa7a65b57e..6fe415903668 100644
 --- a/drivers/gpu/drm/bridge/synopsys/Makefile
 +++ b/drivers/gpu/drm/bridge/synopsys/Makefile
 @@ -3,3 +3,4 @@
   obj-$(CONFIG_DRM_DW_HDMI) += dw-hdmi.o
   obj-$(CONFIG_DRM_DW_HDMI_AHB_AUDIO) += dw-hdmi-ahb-audio.o
   obj-$(CONFIG_DRM_DW_HDMI_I2S_AUDIO) += dw-hdmi-i2s-audio.o
 +obj-$(CONFIG_DRM_DW_HDMI_CEC) += dw-hdmi-cec.o
 diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c
 b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c
 new file mode 100644
 index ..761ef5ae687d
 --- /dev/null
 +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c
 @@ -0,0 +1,320 @@
 +/*
 + * Designware HDMI CEC driver
 + *
 + * Copyright (C) 2015-2017 Russell King.
 + *
 + * This program is free software; you can redistribute it
 and/or modify
 + * it under the terms of the GNU General Public License
 version 2 as
 + * published by the Free Software Foundation.
 + */
 +#include 
 +#include 
 +#include 
 +#include 
 +#include 
 +#include 
 +
 +#include 
 +
 +#include 
 +#include 
 +
 +#include "dw-hdmi-cec.h"
 +
 +enum {
 +HDMI_IH_CEC_STAT0= 0x0106,
 +HDMI_IH_MUTE_CEC_STAT0= 0x0186,
 +
 +HDMI_CEC_CTRL= 0x7d00,
 +CEC_CTRL_START= BIT(0),
 +CEC_CTRL_NORMAL= 1 << 1,
 +
 +HDMI_CEC_STAT= 0x7d01,
 +CEC_STAT_DONE= BIT(0),
 +CEC_STAT_EOM= BIT(1),
 +CEC_STAT_NACK= BIT(2),
 +CEC_STAT_ARBLOST= BIT(3),
 +CEC_STAT_ERROR_INIT= BIT(4),
 +CEC_STAT_ERROR_FOLL= BIT(5),
 +CEC_STAT_WAKEUP= BIT(6),
>>
>> I hadn't realized until Jose Abreu's latest reply, but you need
>> to check the
>> ARBLOST status and set the TX state to CEC_TX_STATUS_ARB_LOST.
>>
>> I think CEC_STAT_ERROR_FOLL might equal
>> CEC_TX_STATUS_LOW_DRIVE, but without
>> documentation I can't be sure.
>>
>> My experience is that this low drive condition tends to be
>> poorly reported by
>> hardware. Either that or poorly documented. This is why I added a
>> CEC_TX_STATUS_ERROR status as a catch-all error status when it
>> is unclear from
>> the hardware/documentation what error occurred.
>>
>> Jose, do you know which status bit is used to report a follower
>> pulling the
>> CEC line low for a long time (approx. 3.6 ms) to signal a CEC
>> error?
> 
> Bit 5 for follower error, bit 4 for initiator error.

I gathered that from the define names :-)

But what does it mean? What sort of error is reported here?

I'm guessing here that "follower error" means that one of the remote
CEC devices forced a Low Drive condition, where "initiator error"
means that our adapter forced a Low Drive condition on the bus.

Would that be correct?

If so, then the CEC_STAT_ERROR_INIT can be ignored and ERROR_FOLL
maps to the LOW_DRIVE status.

(Low Drive condition is what is described in section CEC 7.4 "CEC Line
Error Handling" of the HDMI 1.4 Specification).

Regards,

Hans
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Re: [PATCH 4/4] drm/bridge: dw-hdmi: add cec driver

2017-06-02 Thread Jose Abreu 
Hi Hans,


On 02-06-2017 07:31, Hans Verkuil wrote:
> On 06/01/2017 03:47 PM, Neil Armstrong wrote:
>> On 05/30/2017 04:23 PM, Russell King wrote:
>>> Add a CEC driver for the dw-hdmi hardware.
>>>
>>> Signed-off-by: Russell King 
>>> ---
>>>   drivers/gpu/drm/bridge/synopsys/Kconfig   |   8 +
>>>   drivers/gpu/drm/bridge/synopsys/Makefile  |   1 +
>>>   drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c | 320
>>> ++
>>>   drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.h |  19 ++
>>>   drivers/gpu/drm/bridge/synopsys/dw-hdmi.c |  40 +++-
>>>   5 files changed, 387 insertions(+), 1 deletion(-)
>>>   create mode 100644
>>> drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c
>>>   create mode 100644
>>> drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.h
>>>
>>> diff --git a/drivers/gpu/drm/bridge/synopsys/Kconfig
>>> b/drivers/gpu/drm/bridge/synopsys/Kconfig
>>> index 40d2827a6d19..bd30a0a07272 100644
>>> --- a/drivers/gpu/drm/bridge/synopsys/Kconfig
>>> +++ b/drivers/gpu/drm/bridge/synopsys/Kconfig
>>> @@ -21,3 +21,11 @@ config DRM_DW_HDMI_I2S_AUDIO
>>>   help
>>> Support the I2S Audio interface which is part of the
>>> Synopsys
>>> Designware HDMI block.
>>> +
>>> +config DRM_DW_HDMI_CEC
>>> +tristate "Synopsis Designware CEC interface"
>>> +depends on DRM_DW_HDMI && MEDIA_CEC_SUPPORT
>>> +select MEDIA_CEC_NOTIFIER
>>> +help
>>> +  Support the CE interface which is part of the Synopsis
>>> +  Designware HDMI block.
>>> diff --git a/drivers/gpu/drm/bridge/synopsys/Makefile
>>> b/drivers/gpu/drm/bridge/synopsys/Makefile
>>> index 17aa7a65b57e..6fe415903668 100644
>>> --- a/drivers/gpu/drm/bridge/synopsys/Makefile
>>> +++ b/drivers/gpu/drm/bridge/synopsys/Makefile
>>> @@ -3,3 +3,4 @@
>>>   obj-$(CONFIG_DRM_DW_HDMI) += dw-hdmi.o
>>>   obj-$(CONFIG_DRM_DW_HDMI_AHB_AUDIO) += dw-hdmi-ahb-audio.o
>>>   obj-$(CONFIG_DRM_DW_HDMI_I2S_AUDIO) += dw-hdmi-i2s-audio.o
>>> +obj-$(CONFIG_DRM_DW_HDMI_CEC) += dw-hdmi-cec.o
>>> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c
>>> b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c
>>> new file mode 100644
>>> index ..761ef5ae687d
>>> --- /dev/null
>>> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c
>>> @@ -0,0 +1,320 @@
>>> +/*
>>> + * Designware HDMI CEC driver
>>> + *
>>> + * Copyright (C) 2015-2017 Russell King.
>>> + *
>>> + * This program is free software; you can redistribute it
>>> and/or modify
>>> + * it under the terms of the GNU General Public License
>>> version 2 as
>>> + * published by the Free Software Foundation.
>>> + */
>>> +#include 
>>> +#include 
>>> +#include 
>>> +#include 
>>> +#include 
>>> +#include 
>>> +
>>> +#include 
>>> +
>>> +#include 
>>> +#include 
>>> +
>>> +#include "dw-hdmi-cec.h"
>>> +
>>> +enum {
>>> +HDMI_IH_CEC_STAT0= 0x0106,
>>> +HDMI_IH_MUTE_CEC_STAT0= 0x0186,
>>> +
>>> +HDMI_CEC_CTRL= 0x7d00,
>>> +CEC_CTRL_START= BIT(0),
>>> +CEC_CTRL_NORMAL= 1 << 1,
>>> +
>>> +HDMI_CEC_STAT= 0x7d01,
>>> +CEC_STAT_DONE= BIT(0),
>>> +CEC_STAT_EOM= BIT(1),
>>> +CEC_STAT_NACK= BIT(2),
>>> +CEC_STAT_ARBLOST= BIT(3),
>>> +CEC_STAT_ERROR_INIT= BIT(4),
>>> +CEC_STAT_ERROR_FOLL= BIT(5),
>>> +CEC_STAT_WAKEUP= BIT(6),
>
> I hadn't realized until Jose Abreu's latest reply, but you need
> to check the
> ARBLOST status and set the TX state to CEC_TX_STATUS_ARB_LOST.
>
> I think CEC_STAT_ERROR_FOLL might equal
> CEC_TX_STATUS_LOW_DRIVE, but without
> documentation I can't be sure.
>
> My experience is that this low drive condition tends to be
> poorly reported by
> hardware. Either that or poorly documented. This is why I added a
> CEC_TX_STATUS_ERROR status as a catch-all error status when it
> is unclear from
> the hardware/documentation what error occurred.
>
> Jose, do you know which status bit is used to report a follower
> pulling the
> CEC line low for a long time (approx. 3.6 ms) to signal a CEC
> error?

Bit 5 for follower error, bit 4 for initiator error.

Best regards,
Jose Miguel Abreu

>
> Regards,
>
> Hans

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Re: [PATCH 4/4] drm/bridge: dw-hdmi: add cec driver

2017-06-02 Thread Jose Abreu 


On 01-06-2017 23:30, Russell King - ARM Linux wrote:
> On Thu, Jun 01, 2017 at 01:53:21AM +0100, Jose Abreu wrote:
>> Hi Russell,
>>
>>
>> On 30-05-2017 15:23, Russell King wrote:
>>> +static int dw_hdmi_cec_transmit(struct cec_adapter *adap, u8 attempts,
>>> +   u32 signal_free_time, struct cec_msg *msg)
>>> +{
>>> +   struct dw_hdmi_cec *cec = adap->priv;
>>> +   unsigned i;
>>> +
>>> +   cec->retries = attempts;
>> I think you should check first if CEC engine is in normal
>> operation mode, as a safety measure.
> I'm not sure what you mean there, because the iMX6 manuals don't mention
> anything about that.  The only "modes" it talks about is initiator mode
> and follower mode.  Moreover, there's nothing in what was FSL's driver
> that hints at that either.
>
> Maybe you could provide some further technical information on this
> point?
>

You should check that CEC is: not in standy, acknowledges
broadcast messages, signal free time is 5bit period, and not lost
arbitration, which basically means CEC_CTRL must be 0x2 and
IH_CEC_STAT0 must not have ARB_LOST set. I do know you set 0x3 at
the end of this function but according to all the docs I have you
must first set 0x2 before writing message.

Best regards,
Jose Miguel Abreu
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Re: [PATCH 4/4] drm/bridge: dw-hdmi: add cec driver

2017-06-02 Thread Hans Verkuil 

On 06/01/2017 03:47 PM, Neil Armstrong wrote:

On 05/30/2017 04:23 PM, Russell King wrote:

Add a CEC driver for the dw-hdmi hardware.

Signed-off-by: Russell King 
---
  drivers/gpu/drm/bridge/synopsys/Kconfig   |   8 +
  drivers/gpu/drm/bridge/synopsys/Makefile  |   1 +
  drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c | 320 ++
  drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.h |  19 ++
  drivers/gpu/drm/bridge/synopsys/dw-hdmi.c |  40 +++-
  5 files changed, 387 insertions(+), 1 deletion(-)
  create mode 100644 drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c
  create mode 100644 drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.h

diff --git a/drivers/gpu/drm/bridge/synopsys/Kconfig 
b/drivers/gpu/drm/bridge/synopsys/Kconfig
index 40d2827a6d19..bd30a0a07272 100644
--- a/drivers/gpu/drm/bridge/synopsys/Kconfig
+++ b/drivers/gpu/drm/bridge/synopsys/Kconfig
@@ -21,3 +21,11 @@ config DRM_DW_HDMI_I2S_AUDIO
help
  Support the I2S Audio interface which is part of the Synopsys
  Designware HDMI block.
+
+config DRM_DW_HDMI_CEC
+   tristate "Synopsis Designware CEC interface"
+   depends on DRM_DW_HDMI && MEDIA_CEC_SUPPORT
+   select MEDIA_CEC_NOTIFIER
+   help
+ Support the CE interface which is part of the Synopsis
+ Designware HDMI block.
diff --git a/drivers/gpu/drm/bridge/synopsys/Makefile 
b/drivers/gpu/drm/bridge/synopsys/Makefile
index 17aa7a65b57e..6fe415903668 100644
--- a/drivers/gpu/drm/bridge/synopsys/Makefile
+++ b/drivers/gpu/drm/bridge/synopsys/Makefile
@@ -3,3 +3,4 @@
  obj-$(CONFIG_DRM_DW_HDMI) += dw-hdmi.o
  obj-$(CONFIG_DRM_DW_HDMI_AHB_AUDIO) += dw-hdmi-ahb-audio.o
  obj-$(CONFIG_DRM_DW_HDMI_I2S_AUDIO) += dw-hdmi-i2s-audio.o
+obj-$(CONFIG_DRM_DW_HDMI_CEC) += dw-hdmi-cec.o
diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c 
b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c
new file mode 100644
index ..761ef5ae687d
--- /dev/null
+++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c
@@ -0,0 +1,320 @@
+/*
+ * Designware HDMI CEC driver
+ *
+ * Copyright (C) 2015-2017 Russell King.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include 
+#include 
+#include 
+#include 
+#include 
+#include 
+
+#include 
+
+#include 
+#include 
+
+#include "dw-hdmi-cec.h"
+
+enum {
+   HDMI_IH_CEC_STAT0   = 0x0106,
+   HDMI_IH_MUTE_CEC_STAT0  = 0x0186,
+
+   HDMI_CEC_CTRL   = 0x7d00,
+   CEC_CTRL_START  = BIT(0),
+   CEC_CTRL_NORMAL = 1 << 1,
+
+   HDMI_CEC_STAT   = 0x7d01,
+   CEC_STAT_DONE   = BIT(0),
+   CEC_STAT_EOM= BIT(1),
+   CEC_STAT_NACK   = BIT(2),
+   CEC_STAT_ARBLOST= BIT(3),
+   CEC_STAT_ERROR_INIT = BIT(4),
+   CEC_STAT_ERROR_FOLL = BIT(5),
+   CEC_STAT_WAKEUP = BIT(6),


I hadn't realized until Jose Abreu's latest reply, but you need to check the
ARBLOST status and set the TX state to CEC_TX_STATUS_ARB_LOST.

I think CEC_STAT_ERROR_FOLL might equal CEC_TX_STATUS_LOW_DRIVE, but without
documentation I can't be sure.

My experience is that this low drive condition tends to be poorly reported by
hardware. Either that or poorly documented. This is why I added a
CEC_TX_STATUS_ERROR status as a catch-all error status when it is unclear from
the hardware/documentation what error occurred.

Jose, do you know which status bit is used to report a follower pulling the
CEC line low for a long time (approx. 3.6 ms) to signal a CEC error?

Regards,

Hans
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Re: [PATCH 4/4] drm/bridge: dw-hdmi: add cec driver

2017-06-01 Thread Russell King - ARM Linux 
On Thu, Jun 01, 2017 at 10:31:10AM +0200, Hans Verkuil wrote:
> Hi Russell,
> 
> First a few top-level questions:

Hi Hans,

> 1) What was the reason for using the cec-notifier here? Isn't this
>tightly integrated into the main dw-hdmi block? For the tda driver
>it is clearly required, but for tightly coupled HDMI & CEC HW I
>just create the adapter from the HDMI driver. As a small bonus it
>avoids adding the cec-notifier code and the control flow is a bit
>easier to trace.

It's to avoid complex dependencies.  If it's all built in to the HDMI
driver, then the HDMI driver needs to depend on all the media stuff
being non-modular.  For a video output device, this is sub-optimal,
because you want the video output device to work during boot.

I feel strongly about this point, especially as we have had many years
of users being able to use dw-hdmi without needing CEC enabled.

> 2) I may have asked this before, apologies if I repeat myself: does
>this CEC implementation support CEC monitoring (aka snooping)? If
>it does, then I recommend that it is implemented since it is very
>useful.

It does not.

> 3) Is the CEC still active if there is no hotplug signal? Or is it
>powered off in that case? Ideally it should still be possible to
>send CEC messages even if there is no hotplug. This is explicitly
>allowed by the CEC 2.0 spec to wake up displays that turn off the
>HPD, but that still have a working CEC controller.

This is not specified in the documentation, so I don't think we know
without experimentation.  This would be a future enhancement to the
patch set.

> > diff --git a/drivers/gpu/drm/bridge/synopsys/Kconfig 
> > b/drivers/gpu/drm/bridge/synopsys/Kconfig
> > index 40d2827a6d19..bd30a0a07272 100644
> > --- a/drivers/gpu/drm/bridge/synopsys/Kconfig
> > +++ b/drivers/gpu/drm/bridge/synopsys/Kconfig
> > @@ -21,3 +21,11 @@ config DRM_DW_HDMI_I2S_AUDIO
> > help
> >   Support the I2S Audio interface which is part of the Synopsys
> >   Designware HDMI block.
> > +
> > +config DRM_DW_HDMI_CEC
> > +   tristate "Synopsis Designware CEC interface"
> > +   depends on DRM_DW_HDMI && MEDIA_CEC_SUPPORT
> > +   select MEDIA_CEC_NOTIFIER
> > +   help
> > + Support the CE interface which is part of the Synopsis
> > + Designware HDMI block.
> 
> This will change. Patches to fix the config handling are pending for 4.12.
> 
> Here you can see the pending patches:
> https://git.linuxtv.org/hverkuil/media_tree.git/log/?h=drm-cec
> 
> The patches from 'cec-notifier.h: handle unreachable CONFIG_CEC_CORE' to
> 'cec: drop MEDIA_CEC_DEBUG' should all be merged in 4.12.
> 
> That means that this config becomes:
> 
> +
> +config DRM_DW_HDMI_CEC
> + tristate "Synopsis Designware CEC interface"
> + depends on DRM_DW_HDMI
> + select CEC_CORE
> + select CEC_NOTIFIER
> + help
> +   Support the CE interface which is part of the Synopsis
> +   Designware HDMI block.

You will also need to select MEDIA_SUPPORT to avoid dependency issues.
CEC_CORE and CEC_NOTIFIER are both lumped under an "if MEDIA_SUPPORT"
block in drivers/media/Kconfig, so they depend on this symbol.  Asking
Kconfig to select these two symbols without MEDIA_SUPPORT creates an
invalid configuration - unless CEC has been moved out from being under
MEDIA_SUPPORT.  (I haven't looked at your tree yet.)

> > +static int dw_hdmi_cec_log_addr(struct cec_adapter *adap, u8 logical_addr)
> > +{
> > +   struct dw_hdmi_cec *cec = adap->priv;
> > +   u32 addresses;
> > +
> > +   if (logical_addr == CEC_LOG_ADDR_INVALID)
> > +   addresses = cec->addresses = 0;
> > +   else
> > +   addresses = cec->addresses |= BIT(logical_addr) | BIT(15);
> > +
> > +   dw_hdmi_write(cec, addresses & 255, HDMI_CEC_ADDR_L);
> > +   dw_hdmi_write(cec, addresses >> 8, HDMI_CEC_ADDR_H);
> 
> The addresses local variable doesn't really seem needed.

Ok.

> > +static int dw_hdmi_cec_transmit(struct cec_adapter *adap, u8 attempts,
> > +   u32 signal_free_time, struct cec_msg *msg)
> > +{
> > +   struct dw_hdmi_cec *cec = adap->priv;
> > +   unsigned i;
> > +
> > +   cec->retries = attempts;
> 
> Should probably be 'cec->retries = attempts - 1;'
> Since 2 attempts == 1 retry.

Probably correct, but rather moot given your comment below.

> > +static irqreturn_t dw_hdmi_cec_hardirq(int irq, void *data)
> > +{
> > +   struct cec_adapter *adap = data;
> > +   struct dw_hdmi_cec *cec = adap->priv;
> > +   unsigned stat = dw_hdmi_read(cec, HDMI_IH_CEC_STAT0);
> > +   irqreturn_t ret = IRQ_HANDLED;
> > +
> > +   if (stat == 0)
> > +   return IRQ_NONE;
> > +
> > +   dw_hdmi_write(cec, stat, HDMI_IH_CEC_STAT0);
> > +
> > +   if (stat & CEC_STAT_ERROR_INIT) {
> > +   if (cec->retries) {
> > +   unsigned v = dw_hdmi_read(cec, HDMI_CEC_CTRL);
> > +   dw_hdmi_write(cec, v | CEC_CTRL_START, HDMI_CEC_CTRL);
> > +   cec->retries

Re: [PATCH 4/4] drm/bridge: dw-hdmi: add cec driver

2017-06-01 Thread Russell King - ARM Linux 
On Thu, Jun 01, 2017 at 01:53:21AM +0100, Jose Abreu wrote:
> Hi Russell,
> 
> 
> On 30-05-2017 15:23, Russell King wrote:
> > +static int dw_hdmi_cec_transmit(struct cec_adapter *adap, u8 attempts,
> > +   u32 signal_free_time, struct cec_msg *msg)
> > +{
> > +   struct dw_hdmi_cec *cec = adap->priv;
> > +   unsigned i;
> > +
> > +   cec->retries = attempts;
> 
> I think you should check first if CEC engine is in normal
> operation mode, as a safety measure.

I'm not sure what you mean there, because the iMX6 manuals don't mention
anything about that.  The only "modes" it talks about is initiator mode
and follower mode.  Moreover, there's nothing in what was FSL's driver
that hints at that either.

Maybe you could provide some further technical information on this
point?

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Re: [PATCH 4/4] drm/bridge: dw-hdmi: add cec driver

2017-06-01 Thread Jose Abreu 
Hi Russell,


On 30-05-2017 15:23, Russell King wrote:
> Add a CEC driver for the dw-hdmi hardware.
>
> Signed-off-by: Russell King 
> ---
>  drivers/gpu/drm/bridge/synopsys/Kconfig   |   8 +
>  drivers/gpu/drm/bridge/synopsys/Makefile  |   1 +
>  drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c | 320 
> ++
>  drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.h |  19 ++
>  drivers/gpu/drm/bridge/synopsys/dw-hdmi.c |  40 +++-
>  5 files changed, 387 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c
>  create mode 100644 drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.h
>
> diff --git a/drivers/gpu/drm/bridge/synopsys/Kconfig 
> b/drivers/gpu/drm/bridge/synopsys/Kconfig
> index 40d2827a6d19..bd30a0a07272 100644
> --- a/drivers/gpu/drm/bridge/synopsys/Kconfig
> +++ b/drivers/gpu/drm/bridge/synopsys/Kconfig
> @@ -21,3 +21,11 @@ config DRM_DW_HDMI_I2S_AUDIO
>   help
> Support the I2S Audio interface which is part of the Synopsys
> Designware HDMI block.
> +
> +config DRM_DW_HDMI_CEC
> + tristate "Synopsis Designware CEC interface"
> + depends on DRM_DW_HDMI && MEDIA_CEC_SUPPORT
> + select MEDIA_CEC_NOTIFIER
> + help
> +   Support the CE interface which is part of the Synopsis

Synopsis -> Synopsys

> +   Designware HDMI block.
> diff --git a/drivers/gpu/drm/bridge/synopsys/Makefile 
> b/drivers/gpu/drm/bridge/synopsys/Makefile
> index 17aa7a65b57e..6fe415903668 100644
> --- a/drivers/gpu/drm/bridge/synopsys/Makefile
> +++ b/drivers/gpu/drm/bridge/synopsys/Makefile
> @@ -3,3 +3,4 @@
>  obj-$(CONFIG_DRM_DW_HDMI) += dw-hdmi.o
>  obj-$(CONFIG_DRM_DW_HDMI_AHB_AUDIO) += dw-hdmi-ahb-audio.o
>  obj-$(CONFIG_DRM_DW_HDMI_I2S_AUDIO) += dw-hdmi-i2s-audio.o
> +obj-$(CONFIG_DRM_DW_HDMI_CEC) += dw-hdmi-cec.o
> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c 
> b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c
> new file mode 100644
> index ..761ef5ae687d
> --- /dev/null
> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c
> @@ -0,0 +1,320 @@
> +/*
> + * Designware HDMI CEC driver
> + *
> + * Copyright (C) 2015-2017 Russell King.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +#include 
> +#include 
> +#include 
> +#include 
> +#include 
> +#include 
> +
> +#include 
> +
> +#include 
> +#include 
> +
> +#include "dw-hdmi-cec.h"
> +
> +enum {
> + HDMI_IH_CEC_STAT0   = 0x0106,
> + HDMI_IH_MUTE_CEC_STAT0  = 0x0186,
> +
> + HDMI_CEC_CTRL   = 0x7d00,
> + CEC_CTRL_START  = BIT(0),
> + CEC_CTRL_NORMAL = 1 << 1,
> +
> + HDMI_CEC_STAT   = 0x7d01,
> + CEC_STAT_DONE   = BIT(0),
> + CEC_STAT_EOM= BIT(1),
> + CEC_STAT_NACK   = BIT(2),
> + CEC_STAT_ARBLOST= BIT(3),
> + CEC_STAT_ERROR_INIT = BIT(4),
> + CEC_STAT_ERROR_FOLL = BIT(5),
> + CEC_STAT_WAKEUP = BIT(6),

I rather like the format HDMI_{REGISTER_NAME}_{FIELD_NAME} so
that it clearly identifies this is a internal driver register and
not a CEC core register, but I guess its up to you :)

> +
> + HDMI_CEC_MASK   = 0x7d02,
> + HDMI_CEC_POLARITY   = 0x7d03,
> + HDMI_CEC_INT= 0x7d04,
> + HDMI_CEC_ADDR_L = 0x7d05,
> + HDMI_CEC_ADDR_H = 0x7d06,
> + HDMI_CEC_TX_CNT = 0x7d07,
> + HDMI_CEC_RX_CNT = 0x7d08,
> + HDMI_CEC_TX_DATA0   = 0x7d10,
> + HDMI_CEC_RX_DATA0   = 0x7d20,
> + HDMI_CEC_LOCK   = 0x7d30,
> + HDMI_CEC_WKUPCTRL   = 0x7d31,
> +};
> +
> +struct dw_hdmi_cec {
> + struct dw_hdmi *hdmi;
> + const struct dw_hdmi_cec_ops *ops;
> + u32 addresses;
> + struct cec_adapter *adap;
> + struct cec_msg rx_msg;
> + unsigned int tx_status;
> + bool tx_done;
> + bool rx_done;
> + struct cec_notifier *notify;
> + int retries;
> + int irq;
> +};
> +
> +static void dw_hdmi_write(struct dw_hdmi_cec *cec, u8 val, int offset)
> +{
> + cec->ops->write(cec->hdmi, val, offset);
> +}
> +
> +static u8 dw_hdmi_read(struct dw_hdmi_cec *cec, int offset)
> +{
> + return cec->ops->read(cec->hdmi, offset);
> +}
> +
> +static int dw_hdmi_cec_log_addr(struct cec_adapter *adap, u8 logical_addr)
> +{
> + struct dw_hdmi_cec *cec = adap->priv;

You can use "cec = cec_get_drvdata(adap)" here, as in the rest of
the code.

> + u32 addresses;
> +
> + if (logical_addr == CEC_LOG_ADDR_INVALID)
> + addresses = cec->addresses = 0;
> + else
> + addresses = cec->addresses |= BIT(logical_addr) | BIT(15);
> +
> + dw_hdmi_write(cec, addresses & 255, HDMI_CEC_ADDR_L);
> + dw_hdmi_write(cec, addresses >> 8, HDMI_CEC_ADDR_H);
> +
> + return 0;
> +}
> +
>

Re: [PATCH 4/4] drm/bridge: dw-hdmi: add cec driver

2017-06-01 Thread Neil Armstrong 
On 05/30/2017 04:23 PM, Russell King wrote:
> Add a CEC driver for the dw-hdmi hardware.
> 
> Signed-off-by: Russell King 
> ---
>  drivers/gpu/drm/bridge/synopsys/Kconfig   |   8 +
>  drivers/gpu/drm/bridge/synopsys/Makefile  |   1 +
>  drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c | 320 
> ++
>  drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.h |  19 ++
>  drivers/gpu/drm/bridge/synopsys/dw-hdmi.c |  40 +++-
>  5 files changed, 387 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c
>  create mode 100644 drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.h
> 
> diff --git a/drivers/gpu/drm/bridge/synopsys/Kconfig 
> b/drivers/gpu/drm/bridge/synopsys/Kconfig
> index 40d2827a6d19..bd30a0a07272 100644
> --- a/drivers/gpu/drm/bridge/synopsys/Kconfig
> +++ b/drivers/gpu/drm/bridge/synopsys/Kconfig
> @@ -21,3 +21,11 @@ config DRM_DW_HDMI_I2S_AUDIO
>   help
> Support the I2S Audio interface which is part of the Synopsys
> Designware HDMI block.
> +
> +config DRM_DW_HDMI_CEC
> + tristate "Synopsis Designware CEC interface"
> + depends on DRM_DW_HDMI && MEDIA_CEC_SUPPORT
> + select MEDIA_CEC_NOTIFIER
> + help
> +   Support the CE interface which is part of the Synopsis
> +   Designware HDMI block.
> diff --git a/drivers/gpu/drm/bridge/synopsys/Makefile 
> b/drivers/gpu/drm/bridge/synopsys/Makefile
> index 17aa7a65b57e..6fe415903668 100644
> --- a/drivers/gpu/drm/bridge/synopsys/Makefile
> +++ b/drivers/gpu/drm/bridge/synopsys/Makefile
> @@ -3,3 +3,4 @@
>  obj-$(CONFIG_DRM_DW_HDMI) += dw-hdmi.o
>  obj-$(CONFIG_DRM_DW_HDMI_AHB_AUDIO) += dw-hdmi-ahb-audio.o
>  obj-$(CONFIG_DRM_DW_HDMI_I2S_AUDIO) += dw-hdmi-i2s-audio.o
> +obj-$(CONFIG_DRM_DW_HDMI_CEC) += dw-hdmi-cec.o
> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c 
> b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c
> new file mode 100644
> index ..761ef5ae687d
> --- /dev/null
> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c
> @@ -0,0 +1,320 @@
> +/*
> + * Designware HDMI CEC driver
> + *
> + * Copyright (C) 2015-2017 Russell King.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +#include 
> +#include 
> +#include 
> +#include 
> +#include 
> +#include 
> +
> +#include 
> +
> +#include 
> +#include 
> +
> +#include "dw-hdmi-cec.h"
> +
> +enum {
> + HDMI_IH_CEC_STAT0   = 0x0106,
> + HDMI_IH_MUTE_CEC_STAT0  = 0x0186,
> +
> + HDMI_CEC_CTRL   = 0x7d00,
> + CEC_CTRL_START  = BIT(0),
> + CEC_CTRL_NORMAL = 1 << 1,
> +
> + HDMI_CEC_STAT   = 0x7d01,
> + CEC_STAT_DONE   = BIT(0),
> + CEC_STAT_EOM= BIT(1),
> + CEC_STAT_NACK   = BIT(2),
> + CEC_STAT_ARBLOST= BIT(3),
> + CEC_STAT_ERROR_INIT = BIT(4),
> + CEC_STAT_ERROR_FOLL = BIT(5),
> + CEC_STAT_WAKEUP = BIT(6),
> +
> + HDMI_CEC_MASK   = 0x7d02,
> + HDMI_CEC_POLARITY   = 0x7d03,
> + HDMI_CEC_INT= 0x7d04,
> + HDMI_CEC_ADDR_L = 0x7d05,
> + HDMI_CEC_ADDR_H = 0x7d06,
> + HDMI_CEC_TX_CNT = 0x7d07,
> + HDMI_CEC_RX_CNT = 0x7d08,
> + HDMI_CEC_TX_DATA0   = 0x7d10,
> + HDMI_CEC_RX_DATA0   = 0x7d20,
> + HDMI_CEC_LOCK   = 0x7d30,
> + HDMI_CEC_WKUPCTRL   = 0x7d31,
> +};
> +
> +struct dw_hdmi_cec {
> + struct dw_hdmi *hdmi;
> + const struct dw_hdmi_cec_ops *ops;
> + u32 addresses;
> + struct cec_adapter *adap;
> + struct cec_msg rx_msg;
> + unsigned int tx_status;
> + bool tx_done;
> + bool rx_done;
> + struct cec_notifier *notify;
> + int retries;
> + int irq;
> +};
> +
> +static void dw_hdmi_write(struct dw_hdmi_cec *cec, u8 val, int offset)
> +{
> + cec->ops->write(cec->hdmi, val, offset);
> +}
> +
> +static u8 dw_hdmi_read(struct dw_hdmi_cec *cec, int offset)
> +{
> + return cec->ops->read(cec->hdmi, offset);
> +}
> +
> +static int dw_hdmi_cec_log_addr(struct cec_adapter *adap, u8 logical_addr)
> +{
> + struct dw_hdmi_cec *cec = adap->priv;
> + u32 addresses;
> +
> + if (logical_addr == CEC_LOG_ADDR_INVALID)
> + addresses = cec->addresses = 0;
> + else
> + addresses = cec->addresses |= BIT(logical_addr) | BIT(15);
> +
> + dw_hdmi_write(cec, addresses & 255, HDMI_CEC_ADDR_L);
> + dw_hdmi_write(cec, addresses >> 8, HDMI_CEC_ADDR_H);
> +
> + return 0;
> +}
> +
> +static int dw_hdmi_cec_transmit(struct cec_adapter *adap, u8 attempts,
> + u32 signal_free_time, struct cec_msg *msg)
> +{
> + struct dw_hdmi_cec *cec = adap->priv;
> + unsigned i;
> +
> + cec->retries = attempts;
> +
> + for (i = 0; i < msg->len; i++)
>

Re: [PATCH 4/4] drm/bridge: dw-hdmi: add cec driver

2017-06-01 Thread Hans Verkuil 
On 06/01/17 11:46, Russell King - ARM Linux wrote:
> On Thu, Jun 01, 2017 at 10:31:10AM +0200, Hans Verkuil wrote:
>> Hi Russell,
>>
>> First a few top-level questions:
> 
> Hi Hans,
> 
>> 1) What was the reason for using the cec-notifier here? Isn't this
>>tightly integrated into the main dw-hdmi block? For the tda driver
>>it is clearly required, but for tightly coupled HDMI & CEC HW I
>>just create the adapter from the HDMI driver. As a small bonus it
>>avoids adding the cec-notifier code and the control flow is a bit
>>easier to trace.
> 
> It's to avoid complex dependencies.  If it's all built in to the HDMI
> driver, then the HDMI driver needs to depend on all the media stuff
> being non-modular.  For a video output device, this is sub-optimal,
> because you want the video output device to work during boot.

This is no longer true after my rework of the CEC kernel config.

After doing a 'select CEC_CORE' the cec framework will be compiled
correctly.

It no longer depends on the media subsystem (except if you want to use
the remote control passthrough since the RC framework is part of media).

Selecting CEC_CORE will only select the cec core code.

> 
> I feel strongly about this point, especially as we have had many years
> of users being able to use dw-hdmi without needing CEC enabled.
> 
>> 2) I may have asked this before, apologies if I repeat myself: does
>>this CEC implementation support CEC monitoring (aka snooping)? If
>>it does, then I recommend that it is implemented since it is very
>>useful.
> 
> It does not.
> 
>> 3) Is the CEC still active if there is no hotplug signal? Or is it
>>powered off in that case? Ideally it should still be possible to
>>send CEC messages even if there is no hotplug. This is explicitly
>>allowed by the CEC 2.0 spec to wake up displays that turn off the
>>HPD, but that still have a working CEC controller.
> 
> This is not specified in the documentation, so I don't think we know
> without experimentation.  This would be a future enhancement to the
> patch set.
> 
>>> diff --git a/drivers/gpu/drm/bridge/synopsys/Kconfig 
>>> b/drivers/gpu/drm/bridge/synopsys/Kconfig
>>> index 40d2827a6d19..bd30a0a07272 100644
>>> --- a/drivers/gpu/drm/bridge/synopsys/Kconfig
>>> +++ b/drivers/gpu/drm/bridge/synopsys/Kconfig
>>> @@ -21,3 +21,11 @@ config DRM_DW_HDMI_I2S_AUDIO
>>> help
>>>   Support the I2S Audio interface which is part of the Synopsys
>>>   Designware HDMI block.
>>> +
>>> +config DRM_DW_HDMI_CEC
>>> +   tristate "Synopsis Designware CEC interface"
>>> +   depends on DRM_DW_HDMI && MEDIA_CEC_SUPPORT
>>> +   select MEDIA_CEC_NOTIFIER
>>> +   help
>>> + Support the CE interface which is part of the Synopsis
>>> + Designware HDMI block.
>>
>> This will change. Patches to fix the config handling are pending for 4.12.
>>
>> Here you can see the pending patches:
>> https://git.linuxtv.org/hverkuil/media_tree.git/log/?h=drm-cec
>>
>> The patches from 'cec-notifier.h: handle unreachable CONFIG_CEC_CORE' to
>> 'cec: drop MEDIA_CEC_DEBUG' should all be merged in 4.12.
>>
>> That means that this config becomes:
>>
>> +
>> +config DRM_DW_HDMI_CEC
>> +tristate "Synopsis Designware CEC interface"
>> +depends on DRM_DW_HDMI
>> +select CEC_CORE
>> +select CEC_NOTIFIER
>> +help
>> +  Support the CE interface which is part of the Synopsis
>> +  Designware HDMI block.
> 
> You will also need to select MEDIA_SUPPORT to avoid dependency issues.
> CEC_CORE and CEC_NOTIFIER are both lumped under an "if MEDIA_SUPPORT"
> block in drivers/media/Kconfig, so they depend on this symbol.

No, they've been moved up. They no longer depend on the MEDIA_SUPPORT.
So that's been fixed.

> Asking
> Kconfig to select these two symbols without MEDIA_SUPPORT creates an
> invalid configuration - unless CEC has been moved out from being under
> MEDIA_SUPPORT.  (I haven't looked at your tree yet.)
> 
>>> +static int dw_hdmi_cec_log_addr(struct cec_adapter *adap, u8 logical_addr)
>>> +{
>>> +   struct dw_hdmi_cec *cec = adap->priv;
>>> +   u32 addresses;
>>> +
>>> +   if (logical_addr == CEC_LOG_ADDR_INVALID)
>>> +   addresses = cec->addresses = 0;
>>> +   else
>>> +   addresses = cec->addresses |= BIT(logical_addr) | BIT(15);
>>> +
>>> +   dw_hdmi_write(cec, addresses & 255, HDMI_CEC_ADDR_L);
>>> +   dw_hdmi_write(cec, addresses >> 8, HDMI_CEC_ADDR_H);
>>
>> The addresses local variable doesn't really seem needed.
> 
> Ok.
> 
>>> +static int dw_hdmi_cec_transmit(struct cec_adapter *adap, u8 attempts,
>>> +   u32 signal_free_time, struct cec_msg *msg)
>>> +{
>>> +   struct dw_hdmi_cec *cec = adap->priv;
>>> +   unsigned i;
>>> +
>>> +   cec->retries = attempts;
>>
>> Should probably be 'cec->retries = attempts - 1;'
>> Since 2 attempts == 1 retry.
> 
> Probably correct, but rather moot given your comment below.
> 
>>> +static irqreturn_t dw_hdmi_cec_hardirq(int irq, void

Re: [PATCH 4/4] drm/bridge: dw-hdmi: add cec driver

2017-06-01 Thread Hans Verkuil 
Hi Russell,

First a few top-level questions:

1) What was the reason for using the cec-notifier here? Isn't this
   tightly integrated into the main dw-hdmi block? For the tda driver
   it is clearly required, but for tightly coupled HDMI & CEC HW I
   just create the adapter from the HDMI driver. As a small bonus it
   avoids adding the cec-notifier code and the control flow is a bit
   easier to trace.

2) I may have asked this before, apologies if I repeat myself: does
   this CEC implementation support CEC monitoring (aka snooping)? If
   it does, then I recommend that it is implemented since it is very
   useful.

3) Is the CEC still active if there is no hotplug signal? Or is it
   powered off in that case? Ideally it should still be possible to
   send CEC messages even if there is no hotplug. This is explicitly
   allowed by the CEC 2.0 spec to wake up displays that turn off the
   HPD, but that still have a working CEC controller.

   If this is not possible, then you need to use the CEC_CAP_NEEDS_HPD
   capability. See: https://patchwork.linuxtv.org/patch/41478/

   This will almost certainly be merged for 4.13 since other CEC drivers
   need this as well.

On 05/30/17 16:23, Russell King wrote:
> Add a CEC driver for the dw-hdmi hardware.
> 
> Signed-off-by: Russell King 
> ---
>  drivers/gpu/drm/bridge/synopsys/Kconfig   |   8 +
>  drivers/gpu/drm/bridge/synopsys/Makefile  |   1 +
>  drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c | 320 
> ++
>  drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.h |  19 ++
>  drivers/gpu/drm/bridge/synopsys/dw-hdmi.c |  40 +++-
>  5 files changed, 387 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c
>  create mode 100644 drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.h
> 
> diff --git a/drivers/gpu/drm/bridge/synopsys/Kconfig 
> b/drivers/gpu/drm/bridge/synopsys/Kconfig
> index 40d2827a6d19..bd30a0a07272 100644
> --- a/drivers/gpu/drm/bridge/synopsys/Kconfig
> +++ b/drivers/gpu/drm/bridge/synopsys/Kconfig
> @@ -21,3 +21,11 @@ config DRM_DW_HDMI_I2S_AUDIO
>   help
> Support the I2S Audio interface which is part of the Synopsys
> Designware HDMI block.
> +
> +config DRM_DW_HDMI_CEC
> + tristate "Synopsis Designware CEC interface"
> + depends on DRM_DW_HDMI && MEDIA_CEC_SUPPORT
> + select MEDIA_CEC_NOTIFIER
> + help
> +   Support the CE interface which is part of the Synopsis
> +   Designware HDMI block.

This will change. Patches to fix the config handling are pending for 4.12.

Here you can see the pending patches:
https://git.linuxtv.org/hverkuil/media_tree.git/log/?h=drm-cec

The patches from 'cec-notifier.h: handle unreachable CONFIG_CEC_CORE' to
'cec: drop MEDIA_CEC_DEBUG' should all be merged in 4.12.

That means that this config becomes:

+
+config DRM_DW_HDMI_CEC
+   tristate "Synopsis Designware CEC interface"
+   depends on DRM_DW_HDMI
+   select CEC_CORE
+   select CEC_NOTIFIER
+   help
+ Support the CE interface which is part of the Synopsis
+ Designware HDMI block.

> diff --git a/drivers/gpu/drm/bridge/synopsys/Makefile 
> b/drivers/gpu/drm/bridge/synopsys/Makefile
> index 17aa7a65b57e..6fe415903668 100644
> --- a/drivers/gpu/drm/bridge/synopsys/Makefile
> +++ b/drivers/gpu/drm/bridge/synopsys/Makefile
> @@ -3,3 +3,4 @@
>  obj-$(CONFIG_DRM_DW_HDMI) += dw-hdmi.o
>  obj-$(CONFIG_DRM_DW_HDMI_AHB_AUDIO) += dw-hdmi-ahb-audio.o
>  obj-$(CONFIG_DRM_DW_HDMI_I2S_AUDIO) += dw-hdmi-i2s-audio.o
> +obj-$(CONFIG_DRM_DW_HDMI_CEC) += dw-hdmi-cec.o
> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c 
> b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c
> new file mode 100644
> index ..761ef5ae687d
> --- /dev/null
> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c
> @@ -0,0 +1,320 @@
> +/*
> + * Designware HDMI CEC driver
> + *
> + * Copyright (C) 2015-2017 Russell King.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +#include 
> +#include 
> +#include 
> +#include 
> +#include 
> +#include 
> +
> +#include 
> +
> +#include 
> +#include 
> +
> +#include "dw-hdmi-cec.h"
> +
> +enum {
> + HDMI_IH_CEC_STAT0   = 0x0106,
> + HDMI_IH_MUTE_CEC_STAT0  = 0x0186,
> +
> + HDMI_CEC_CTRL   = 0x7d00,
> + CEC_CTRL_START  = BIT(0),
> + CEC_CTRL_NORMAL = 1 << 1,
> +
> + HDMI_CEC_STAT   = 0x7d01,
> + CEC_STAT_DONE   = BIT(0),
> + CEC_STAT_EOM= BIT(1),
> + CEC_STAT_NACK   = BIT(2),
> + CEC_STAT_ARBLOST= BIT(3),
> + CEC_STAT_ERROR_INIT = BIT(4),
> + CEC_STAT_ERROR_FOLL = BIT(5),
> + CEC_STAT_WAKEUP = BIT(6),
> +
> + HDMI_CEC_MASK   = 0x7d02,
> + HDMI_CEC_POLARITY   =