diff mbox

[v2,3/4] drm/bridge: dw-hdmi: add cec driver

Message ID E1dcBhf-00088t-Os@rmk-PC.armlinux.org.uk (mailing list archive)
State New, archived
Headers show

Commit Message

Russell King (Oracle) July 31, 2017, 2:29 p.m. UTC 
Add a CEC driver for the dw-hdmi hardware.

Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
---
 drivers/gpu/drm/bridge/synopsys/Kconfig       |   9 +
 drivers/gpu/drm/bridge/synopsys/Makefile      |   1 +
 drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c | 326 ++++++++++++++++++++++++++
 drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.h |  19 ++
 drivers/gpu/drm/bridge/synopsys/dw-hdmi.c     |  42 +++-
 drivers/gpu/drm/bridge/synopsys/dw-hdmi.h     |   1 +
 6 files changed, 397 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

Comments

Hans Verkuil July 31, 2017, 3:35 p.m. UTC | #1 
Hi Russell,

Just two small comments below.

After that's fixed you can add my:

Acked-by: Hans Verkuil <hans.verkuil@cisco.com>

and:

Tested-by: Hans Verkuil <hans.verkuil@cisco.com>

(on my SolidRun Cubox-i).

On 07/31/2017 04:29 PM, Russell King wrote:
> Add a CEC driver for the dw-hdmi hardware.
> 
> Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
> ---
>  drivers/gpu/drm/bridge/synopsys/Kconfig       |   9 +
>  drivers/gpu/drm/bridge/synopsys/Makefile      |   1 +
>  drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c | 326 ++++++++++++++++++++++++++
>  drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.h |  19 ++
>  drivers/gpu/drm/bridge/synopsys/dw-hdmi.c     |  42 +++-
>  drivers/gpu/drm/bridge/synopsys/dw-hdmi.h     |   1 +
>  6 files changed, 397 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
> 

<snip>

> 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 000000000000..52c9d93b9602
> --- /dev/null
> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c
> @@ -0,0 +1,326 @@

<snip>

> +static irqreturn_t dw_hdmi_cec_thread(int irq, void *data)
> +{
> +	struct cec_adapter *adap = data;
> +	struct dw_hdmi_cec *cec = cec_get_drvdata(adap);
> +
> +	if (cec->tx_done) {
> +		cec->tx_done = false;
> +		cec_transmit_done(adap, cec->tx_status, 0, 0, 0, 0);

Replace by:

		cec_transmit_attempt_done(adap, cec->tx_status);

This gets the counters right.

> +	}
> +	if (cec->rx_done) {
> +		cec->rx_done = false;
> +		smp_rmb();
> +		cec_received_msg(adap, &cec->rx_msg);
> +	}
> +	return IRQ_HANDLED;
> +}
> +
> +static int dw_hdmi_cec_probe(struct platform_device *pdev)
> +{
> +	struct dw_hdmi_cec_data *data = dev_get_platdata(&pdev->dev);
> +	struct dw_hdmi_cec *cec;
> +	int ret;
> +
> +	if (!data)
> +		return -ENXIO;
> +
> +	/*
> +	 * Our device is just a convenience - we want to link to the real
> +	 * hardware device here, so that userspace can see the association
> +	 * between the HDMI hardware and its associated CEC chardev.
> +	 */
> +	cec = devm_kzalloc(&pdev->dev, sizeof(*cec), GFP_KERNEL);
> +	if (!cec)
> +		return -ENOMEM;
> +
> +	cec->irq = data->irq;
> +	cec->ops = data->ops;
> +	cec->hdmi = data->hdmi;
> +
> +	platform_set_drvdata(pdev, cec);
> +
> +	dw_hdmi_write(cec, 0, HDMI_CEC_TX_CNT);
> +	dw_hdmi_write(cec, ~0, HDMI_CEC_MASK);
> +	dw_hdmi_write(cec, ~0, HDMI_IH_MUTE_CEC_STAT0);
> +	dw_hdmi_write(cec, 0, HDMI_CEC_POLARITY);
> +
> +	cec->adap = cec_allocate_adapter(&dw_hdmi_cec_ops, cec, "dw_hdmi",
> +					 CEC_CAP_LOG_ADDRS | CEC_CAP_TRANSMIT |
> +					 CEC_CAP_RC, CEC_MAX_LOG_ADDRS);

Add the missing CEC_CAP_PASSTHROUGH capability.

I think I am going to add a new define to media/cec.h:

#define CEC_CAP_DEFAULTS (CEC_CAP_LOG_ADDRS | CEC_CAP_TRANSMIT | \
			  CEC_CAP_PASSTHROUGH | CEC_CAP_RC)

to simplify this since these are standard capabilities.

But that's something I'll do later. For now just add CEC_CAP_PASSTHROUGH.

> +	if (IS_ERR(cec->adap))
> +		return PTR_ERR(cec->adap);
> +
> +	/* override the module pointer */
> +	cec->adap->owner = THIS_MODULE;
> +
> +	ret = devm_add_action(&pdev->dev, dw_hdmi_cec_del, cec);
> +	if (ret) {
> +		cec_delete_adapter(cec->adap);
> +		return ret;
> +	}
> +
> +	ret = devm_request_threaded_irq(&pdev->dev, cec->irq,
> +					dw_hdmi_cec_hardirq,
> +					dw_hdmi_cec_thread, IRQF_SHARED,
> +					"dw-hdmi-cec", cec->adap);
> +	if (ret < 0)
> +		return ret;
> +
> +	cec->notify = cec_notifier_get(pdev->dev.parent);
> +	if (!cec->notify)
> +		return -ENOMEM;
> +
> +	ret = cec_register_adapter(cec->adap, pdev->dev.parent);
> +	if (ret < 0) {
> +		cec_notifier_put(cec->notify);
> +		return ret;
> +	}
> +
> +	/*
> +	 * CEC documentation says we must not call cec_delete_adapter
> +	 * after a successful call to cec_register_adapter().
> +	 */
> +	devm_remove_action(&pdev->dev, dw_hdmi_cec_del, cec);
> +
> +	cec_register_cec_notifier(cec->adap, cec->notify);
> +
> +	return 0;
> +}

<snip>

Thank you for writing this driver!

	Hans
Laurent Pinchart Aug. 1, 2017, 10:32 p.m. UTC | #2 
Hi Russell,

Thank you for the patch.

On Monday 31 Jul 2017 15:29:51 Russell King wrote:
> Add a CEC driver for the dw-hdmi hardware.
> 
> Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
> ---
>  drivers/gpu/drm/bridge/synopsys/Kconfig       |   9 +
>  drivers/gpu/drm/bridge/synopsys/Makefile      |   1 +
>  drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c | 326 +++++++++++++++++++++++
>  drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.h |  19 ++
>  drivers/gpu/drm/bridge/synopsys/dw-hdmi.c     |  42 +++-
>  drivers/gpu/drm/bridge/synopsys/dw-hdmi.h     |   1 +
>  6 files changed, 397 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

[snip]

> 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 000000000000..52c9d93b9602
> --- /dev/null
> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c

[snip]

> +static int dw_hdmi_cec_probe(struct platform_device *pdev)
> +{
> +	struct dw_hdmi_cec_data *data = dev_get_platdata(&pdev->dev);
> +	struct dw_hdmi_cec *cec;
> +	int ret;
> +
> +	if (!data)
> +		return -ENXIO;
> +
> +	/*
> +	 * Our device is just a convenience - we want to link to the real
> +	 * hardware device here, so that userspace can see the association
> +	 * between the HDMI hardware and its associated CEC chardev.
> +	 */
> +	cec = devm_kzalloc(&pdev->dev, sizeof(*cec), GFP_KERNEL);
> +	if (!cec)
> +		return -ENOMEM;
> +
> +	cec->irq = data->irq;
> +	cec->ops = data->ops;
> +	cec->hdmi = data->hdmi;
> +
> +	platform_set_drvdata(pdev, cec);
> +
> +	dw_hdmi_write(cec, 0, HDMI_CEC_TX_CNT);
> +	dw_hdmi_write(cec, ~0, HDMI_CEC_MASK);
> +	dw_hdmi_write(cec, ~0, HDMI_IH_MUTE_CEC_STAT0);
> +	dw_hdmi_write(cec, 0, HDMI_CEC_POLARITY);
> +
> +	cec->adap = cec_allocate_adapter(&dw_hdmi_cec_ops, cec, "dw_hdmi",
> +					 CEC_CAP_LOG_ADDRS | CEC_CAP_TRANSMIT 
|
> +					 CEC_CAP_RC, CEC_MAX_LOG_ADDRS);
> +	if (IS_ERR(cec->adap))
> +		return PTR_ERR(cec->adap);
> +
> +	/* override the module pointer */
> +	cec->adap->owner = THIS_MODULE;
> +
> +	ret = devm_add_action(&pdev->dev, dw_hdmi_cec_del, cec);
> +	if (ret) {
> +		cec_delete_adapter(cec->adap);
> +		return ret;
> +	}
> +
> +	ret = devm_request_threaded_irq(&pdev->dev, cec->irq,
> +					dw_hdmi_cec_hardirq,
> +					dw_hdmi_cec_thread, IRQF_SHARED,
> +					"dw-hdmi-cec", cec->adap);
> +	if (ret < 0)
> +		return ret;
> +
> +	cec->notify = cec_notifier_get(pdev->dev.parent);
> +	if (!cec->notify)
> +		return -ENOMEM;
> +
> +	ret = cec_register_adapter(cec->adap, pdev->dev.parent);
> +	if (ret < 0) {
> +		cec_notifier_put(cec->notify);
> +		return ret;
> +	}
> +
> +	/*
> +	 * CEC documentation says we must not call cec_delete_adapter
> +	 * after a successful call to cec_register_adapter().
> +	 */
> +	devm_remove_action(&pdev->dev, dw_hdmi_cec_del, cec);

dw_hdmi_cec_del() is only used to clean up in the error path of the probe 
function. It would be simpler and less resource-consuming to add an error 
label to this function instead of using devm.

> +
> +	cec_register_cec_notifier(cec->adap, cec->notify);
> +
> +	return 0;
> +}
> +
> +static int dw_hdmi_cec_remove(struct platform_device *pdev)
> +{
> +	struct dw_hdmi_cec *cec = platform_get_drvdata(pdev);
> +
> +	cec_unregister_adapter(cec->adap);
> +	cec_notifier_put(cec->notify);
> +
> +	return 0;
> +}
> +
> +static struct platform_driver dw_hdmi_cec_driver = {
> +	.probe	= dw_hdmi_cec_probe,
> +	.remove	= dw_hdmi_cec_remove,
> +	.driver = {
> +		.name = "dw-hdmi-cec",
> +	},
> +};
> +module_platform_driver(dw_hdmi_cec_driver);

Is there a particular reason why this has to be a separate module instead of 
simply calling the CEC init/cleanup functions directly from the main dw-hdmi 
driver ?

> +MODULE_AUTHOR("Russell King <rmk+kernel@armlinux.org.uk>");
> +MODULE_DESCRIPTION("Synopsys Designware HDMI CEC driver for i.MX");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS(PLATFORM_MODULE_PREFIX "dw-hdmi-cec");
Hans Verkuil Aug. 2, 2017, 6:47 a.m. UTC | #3 
On 08/02/2017 12:32 AM, Laurent Pinchart wrote:
>> +
>> +	cec_register_cec_notifier(cec->adap, cec->notify);
>> +
>> +	return 0;
>> +}
>> +
>> +static int dw_hdmi_cec_remove(struct platform_device *pdev)
>> +{
>> +	struct dw_hdmi_cec *cec = platform_get_drvdata(pdev);
>> +
>> +	cec_unregister_adapter(cec->adap);
>> +	cec_notifier_put(cec->notify);
>> +
>> +	return 0;
>> +}
>> +
>> +static struct platform_driver dw_hdmi_cec_driver = {
>> +	.probe	= dw_hdmi_cec_probe,
>> +	.remove	= dw_hdmi_cec_remove,
>> +	.driver = {
>> +		.name = "dw-hdmi-cec",
>> +	},
>> +};
>> +module_platform_driver(dw_hdmi_cec_driver);
> 
> Is there a particular reason why this has to be a separate module instead of 
> simply calling the CEC init/cleanup functions directly from the main dw-hdmi 
> driver ?

Not all SoCs that use dw-hdmi also use the dw-hdmi CEC implementation. Some
use their own implementation (amlogic). So by implementing the cec-notifier in
the dw-hdmi driver and keeping dw-hdmi CEC separate you can easily choose
whether or not you want to use this CEC driver or another SoC CEC driver.

Regards,

	Hans

> 
>> +MODULE_AUTHOR("Russell King <rmk+kernel@armlinux.org.uk>");
>> +MODULE_DESCRIPTION("Synopsys Designware HDMI CEC driver for i.MX");
>> +MODULE_LICENSE("GPL");
>> +MODULE_ALIAS(PLATFORM_MODULE_PREFIX "dw-hdmi-cec");
>
Laurent Pinchart Aug. 2, 2017, 1:14 p.m. UTC | #4 
Hi Hans,

On Wednesday 02 Aug 2017 08:47:23 Hans Verkuil wrote:
> On 08/02/2017 12:32 AM, Laurent Pinchart wrote:
> >> +
> >> +	cec_register_cec_notifier(cec->adap, cec->notify);
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +static int dw_hdmi_cec_remove(struct platform_device *pdev)
> >> +{
> >> +	struct dw_hdmi_cec *cec = platform_get_drvdata(pdev);
> >> +
> >> +	cec_unregister_adapter(cec->adap);
> >> +	cec_notifier_put(cec->notify);
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +static struct platform_driver dw_hdmi_cec_driver = {
> >> +	.probe	= dw_hdmi_cec_probe,
> >> +	.remove	= dw_hdmi_cec_remove,
> >> +	.driver = {
> >> +		.name = "dw-hdmi-cec",
> >> +	},
> >> +};
> >> +module_platform_driver(dw_hdmi_cec_driver);
> > 
> > Is there a particular reason why this has to be a separate module instead
> > of simply calling the CEC init/cleanup functions directly from the main
> > dw-hdmi driver ?
> 
> Not all SoCs that use dw-hdmi also use the dw-hdmi CEC implementation. Some
> use their own implementation (amlogic).

Lovely. Of course we need to reinvent the wheel every time, where would the 
fun be otherwise ?

> So by implementing the cec-notifier in the dw-hdmi driver and keeping dw-
> hdmi CEC separate you can easily choose whether or not you want to use this
> CEC driver or another SoC CEC driver.

I'm certainly fine with such a split, but I don't think it requires a separate 
platform_driver. We could use a similar approach as with the HDMI PHY that can 
also differ between SoCs. The PHY is identified at runtime when possible, and 
the SoC-specific glue code can override that with a few data fields and 
function pointers.

> >> +MODULE_AUTHOR("Russell King <rmk+kernel@armlinux.org.uk>");
> >> +MODULE_DESCRIPTION("Synopsys Designware HDMI CEC driver for i.MX");
> >> +MODULE_LICENSE("GPL");
> >> +MODULE_ALIAS(PLATFORM_MODULE_PREFIX "dw-hdmi-cec");
Russell King (Oracle) Aug. 2, 2017, 1:27 p.m. UTC | #5 
On Wed, Aug 02, 2017 at 04:14:34PM +0300, Laurent Pinchart wrote:
> Hi Hans,
> 
> On Wednesday 02 Aug 2017 08:47:23 Hans Verkuil wrote:
> > On 08/02/2017 12:32 AM, Laurent Pinchart wrote:
> > >> +
> > >> +	cec_register_cec_notifier(cec->adap, cec->notify);
> > >> +
> > >> +	return 0;
> > >> +}
> > >> +
> > >> +static int dw_hdmi_cec_remove(struct platform_device *pdev)
> > >> +{
> > >> +	struct dw_hdmi_cec *cec = platform_get_drvdata(pdev);
> > >> +
> > >> +	cec_unregister_adapter(cec->adap);
> > >> +	cec_notifier_put(cec->notify);
> > >> +
> > >> +	return 0;
> > >> +}
> > >> +
> > >> +static struct platform_driver dw_hdmi_cec_driver = {
> > >> +	.probe	= dw_hdmi_cec_probe,
> > >> +	.remove	= dw_hdmi_cec_remove,
> > >> +	.driver = {
> > >> +		.name = "dw-hdmi-cec",
> > >> +	},
> > >> +};
> > >> +module_platform_driver(dw_hdmi_cec_driver);
> > > 
> > > Is there a particular reason why this has to be a separate module instead
> > > of simply calling the CEC init/cleanup functions directly from the main
> > > dw-hdmi driver ?
> > 
> > Not all SoCs that use dw-hdmi also use the dw-hdmi CEC implementation. Some
> > use their own implementation (amlogic).
> 
> Lovely. Of course we need to reinvent the wheel every time, where would the 
> fun be otherwise ?
> 
> > So by implementing the cec-notifier in the dw-hdmi driver and keeping dw-
> > hdmi CEC separate you can easily choose whether or not you want to use this
> > CEC driver or another SoC CEC driver.
> 
> I'm certainly fine with such a split, but I don't think it requires a separate 
> platform_driver. We could use a similar approach as with the HDMI PHY that can 
> also differ between SoCs. The PHY is identified at runtime when possible, and 
> the SoC-specific glue code can override that with a few data fields and 
> function pointers.

Excuse me if I completely lose interest in reworking the driver at this
point, as it's enough of an effort to follow the churn in CEC from one
kernel version to another.  I'm not about to rewrite the driver and
restart the review cycle from scratch and then have several iterations
of having to update it as CEC continues to evolve.

Let's get this driver in mainline, and then if we want further changes
we can do that later.
Hans Verkuil Aug. 2, 2017, 1:34 p.m. UTC | #6 
On 08/02/17 15:27, Russell King - ARM Linux wrote:
> On Wed, Aug 02, 2017 at 04:14:34PM +0300, Laurent Pinchart wrote:
>> Hi Hans,
>>
>> On Wednesday 02 Aug 2017 08:47:23 Hans Verkuil wrote:
>>> On 08/02/2017 12:32 AM, Laurent Pinchart wrote:
>>>>> +
>>>>> +	cec_register_cec_notifier(cec->adap, cec->notify);
>>>>> +
>>>>> +	return 0;
>>>>> +}
>>>>> +
>>>>> +static int dw_hdmi_cec_remove(struct platform_device *pdev)
>>>>> +{
>>>>> +	struct dw_hdmi_cec *cec = platform_get_drvdata(pdev);
>>>>> +
>>>>> +	cec_unregister_adapter(cec->adap);
>>>>> +	cec_notifier_put(cec->notify);
>>>>> +
>>>>> +	return 0;
>>>>> +}
>>>>> +
>>>>> +static struct platform_driver dw_hdmi_cec_driver = {
>>>>> +	.probe	= dw_hdmi_cec_probe,
>>>>> +	.remove	= dw_hdmi_cec_remove,
>>>>> +	.driver = {
>>>>> +		.name = "dw-hdmi-cec",
>>>>> +	},
>>>>> +};
>>>>> +module_platform_driver(dw_hdmi_cec_driver);
>>>>
>>>> Is there a particular reason why this has to be a separate module instead
>>>> of simply calling the CEC init/cleanup functions directly from the main
>>>> dw-hdmi driver ?
>>>
>>> Not all SoCs that use dw-hdmi also use the dw-hdmi CEC implementation. Some
>>> use their own implementation (amlogic).
>>
>> Lovely. Of course we need to reinvent the wheel every time, where would the 
>> fun be otherwise ?
>>
>>> So by implementing the cec-notifier in the dw-hdmi driver and keeping dw-
>>> hdmi CEC separate you can easily choose whether or not you want to use this
>>> CEC driver or another SoC CEC driver.
>>
>> I'm certainly fine with such a split, but I don't think it requires a separate 
>> platform_driver. We could use a similar approach as with the HDMI PHY that can 
>> also differ between SoCs. The PHY is identified at runtime when possible, and 
>> the SoC-specific glue code can override that with a few data fields and 
>> function pointers.
> 
> Excuse me if I completely lose interest in reworking the driver at this
> point, as it's enough of an effort to follow the churn in CEC from one
> kernel version to another.  I'm not about to rewrite the driver and
> restart the review cycle from scratch and then have several iterations
> of having to update it as CEC continues to evolve.
> 
> Let's get this driver in mainline, and then if we want further changes
> we can do that later.

+1

I also don't think the phy idea applies here. CEC implementations range from
tightly coupled to the HDMI implementation to a completely independent i2c
device that is unrelated to any HDMI receiver/transmitter. And various shades
in between those extremes.

The only thing that is needed is that the CEC device needs to be informed when
an EDID is read and when the hotplug disappears. The CEC notifier does just
that and it is already in use, so it is nothing new. No need to rework this.

Regards,

	Hans
Laurent Pinchart Aug. 2, 2017, 2:22 p.m. UTC | #7 
Hi Hans,

On Wednesday 02 Aug 2017 15:34:33 Hans Verkuil wrote:
> On 08/02/17 15:27, Russell King - ARM Linux wrote:
> > On Wed, Aug 02, 2017 at 04:14:34PM +0300, Laurent Pinchart wrote:
> >> On Wednesday 02 Aug 2017 08:47:23 Hans Verkuil wrote:
> >>> On 08/02/2017 12:32 AM, Laurent Pinchart wrote:
> >>>>> +
> >>>>> +	cec_register_cec_notifier(cec->adap, cec->notify);
> >>>>> +
> >>>>> +	return 0;
> >>>>> +}
> >>>>> +
> >>>>> +static int dw_hdmi_cec_remove(struct platform_device *pdev)
> >>>>> +{
> >>>>> +	struct dw_hdmi_cec *cec = platform_get_drvdata(pdev);
> >>>>> +
> >>>>> +	cec_unregister_adapter(cec->adap);
> >>>>> +	cec_notifier_put(cec->notify);
> >>>>> +
> >>>>> +	return 0;
> >>>>> +}
> >>>>> +
> >>>>> +static struct platform_driver dw_hdmi_cec_driver = {
> >>>>> +	.probe	= dw_hdmi_cec_probe,
> >>>>> +	.remove	= dw_hdmi_cec_remove,
> >>>>> +	.driver = {
> >>>>> +		.name = "dw-hdmi-cec",
> >>>>> +	},
> >>>>> +};
> >>>>> +module_platform_driver(dw_hdmi_cec_driver);
> >>>> 
> >>>> Is there a particular reason why this has to be a separate module
> >>>> instead of simply calling the CEC init/cleanup functions directly from
> >>>> the main dw-hdmi driver ?
> >>> 
> >>> Not all SoCs that use dw-hdmi also use the dw-hdmi CEC implementation.
> >>> Some use their own implementation (amlogic).
> >> 
> >> Lovely. Of course we need to reinvent the wheel every time, where would
> >> the fun be otherwise ?
> >> 
> >>> So by implementing the cec-notifier in the dw-hdmi driver and keeping
> >>> dw-hdmi CEC separate you can easily choose whether or not you want to
> >>> use this CEC driver or another SoC CEC driver.
> >> 
> >> I'm certainly fine with such a split, but I don't think it requires a
> >> separate platform_driver. We could use a similar approach as with the
> >> HDMI PHY that can also differ between SoCs. The PHY is identified at
> >> runtime when possible, and the SoC-specific glue code can override that
> >> with a few data fields and function pointers.
> > 
> > Excuse me if I completely lose interest in reworking the driver at this
> > point, as it's enough of an effort to follow the churn in CEC from one
> > kernel version to another.  I'm not about to rewrite the driver and
> > restart the review cycle from scratch and then have several iterations
> > of having to update it as CEC continues to evolve.
> > 
> > Let's get this driver in mainline, and then if we want further changes
> > we can do that later.
> 
> +1
> 
> I also don't think the phy idea applies here. CEC implementations range from
> tightly coupled to the HDMI implementation to a completely independent i2c
> device that is unrelated to any HDMI receiver/transmitter. And various
> shades in between those extremes.

Then it should be even simpler. Instead of creating a separate platform device 
for the DW HDMI CEC, we can just call the DW HDMI CEC driver init/cleanup 
functions directly when the IP core implements CEC. When it doesn't, a 
separate device will be described in DT (at least to my understanding, 
otherwise where would it come from ?) and a separate driver would handle it.

> The only thing that is needed is that the CEC device needs to be informed
> when an EDID is read and when the hotplug disappears. The CEC notifier does
> just that and it is already in use, so it is nothing new. No need to rework
> this.

The notifier implementation in patch 1/4 looks good to me (except for the 
missing cec_notifier_put() call that I mentioned in my review).
Russell King (Oracle) Aug. 2, 2017, 5:43 p.m. UTC | #8 
On Wed, Aug 02, 2017 at 05:22:54PM +0300, Laurent Pinchart wrote:
> Then it should be even simpler. Instead of creating a separate platform device 
> for the DW HDMI CEC, we can just call the DW HDMI CEC driver init/cleanup 
> functions directly when the IP core implements CEC. When it doesn't, a 
> separate device will be described in DT (at least to my understanding, 
> otherwise where would it come from ?) and a separate driver would handle it.

Let me put this plainly, because my previous message seems not to have
the desired effect.

I am not changing this driver again until it is merged.
diff mbox

Patch

diff --git a/drivers/gpu/drm/bridge/synopsys/Kconfig b/drivers/gpu/drm/bridge/synopsys/Kconfig
index 351db000599a..d34c3dc04ba9 100644
--- a/drivers/gpu/drm/bridge/synopsys/Kconfig
+++ b/drivers/gpu/drm/bridge/synopsys/Kconfig
@@ -23,3 +23,12 @@  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
+	select CEC_CORE
+	select CEC_NOTIFIER
+	help
+	  Support the CE interface which is part of the 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 000000000000..52c9d93b9602
--- /dev/null
+++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c
@@ -0,0 +1,326 @@ 
+/*
+ * 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 <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+
+#include <drm/drm_edid.h>
+
+#include <media/cec.h>
+#include <media/cec-notifier.h>
+
+#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_FRAME_TYP	= 3 << 1,
+	CEC_CTRL_RETRY		= 0 << 1,
+	CEC_CTRL_NORMAL		= 1 << 1,
+	CEC_CTRL_IMMED		= 2 << 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 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 = cec_get_drvdata(adap);
+
+	if (logical_addr == CEC_LOG_ADDR_INVALID)
+		cec->addresses = 0;
+	else
+		cec->addresses |= BIT(logical_addr) | BIT(15);
+
+	dw_hdmi_write(cec, cec->addresses & 255, HDMI_CEC_ADDR_L);
+	dw_hdmi_write(cec, 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 = cec_get_drvdata(adap);
+	unsigned i, ctrl;
+
+	switch (signal_free_time) {
+	case CEC_SIGNAL_FREE_TIME_RETRY:
+		ctrl = CEC_CTRL_RETRY;
+		break;
+	case CEC_SIGNAL_FREE_TIME_NEW_INITIATOR:
+	default:
+		ctrl = CEC_CTRL_NORMAL;
+		break;
+	case CEC_SIGNAL_FREE_TIME_NEXT_XFER:
+		ctrl = CEC_CTRL_IMMED;
+		break;
+	}
+
+	for (i = 0; i < msg->len; i++)
+		dw_hdmi_write(cec, msg->msg[i], HDMI_CEC_TX_DATA0 + i);
+
+	dw_hdmi_write(cec, msg->len, HDMI_CEC_TX_CNT);
+	dw_hdmi_write(cec, ctrl | CEC_CTRL_START, HDMI_CEC_CTRL);
+
+	return 0;
+}
+
+static irqreturn_t dw_hdmi_cec_hardirq(int irq, void *data)
+{
+	struct cec_adapter *adap = data;
+	struct dw_hdmi_cec *cec = cec_get_drvdata(adap);
+	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) {
+		cec->tx_status = CEC_TX_STATUS_ERROR;
+		cec->tx_done = true;
+		ret = IRQ_WAKE_THREAD;
+	} else if (stat & CEC_STAT_DONE) {
+		cec->tx_status = CEC_TX_STATUS_OK;
+		cec->tx_done = true;
+		ret = IRQ_WAKE_THREAD;
+	} else if (stat & CEC_STAT_NACK) {
+		cec->tx_status = CEC_TX_STATUS_NACK;
+		cec->tx_done = true;
+		ret = IRQ_WAKE_THREAD;
+	}
+
+	if (stat & CEC_STAT_EOM) {
+		unsigned len, i;
+
+		len = dw_hdmi_read(cec, HDMI_CEC_RX_CNT);
+		if (len > sizeof(cec->rx_msg.msg))
+			len = sizeof(cec->rx_msg.msg);
+
+		for (i = 0; i < len; i++)
+			cec->rx_msg.msg[i] =
+				dw_hdmi_read(cec, HDMI_CEC_RX_DATA0 + i);
+
+		dw_hdmi_write(cec, 0, HDMI_CEC_LOCK);
+
+		cec->rx_msg.len = len;
+		smp_wmb();
+		cec->rx_done = true;
+
+		ret = IRQ_WAKE_THREAD;
+	}
+
+	return ret;
+}
+
+static irqreturn_t dw_hdmi_cec_thread(int irq, void *data)
+{
+	struct cec_adapter *adap = data;
+	struct dw_hdmi_cec *cec = cec_get_drvdata(adap);
+
+	if (cec->tx_done) {
+		cec->tx_done = false;
+		cec_transmit_done(adap, cec->tx_status, 0, 0, 0, 0);
+	}
+	if (cec->rx_done) {
+		cec->rx_done = false;
+		smp_rmb();
+		cec_received_msg(adap, &cec->rx_msg);
+	}
+	return IRQ_HANDLED;
+}
+
+static int dw_hdmi_cec_enable(struct cec_adapter *adap, bool enable)
+{
+	struct dw_hdmi_cec *cec = cec_get_drvdata(adap);
+
+	if (!enable) {
+		dw_hdmi_write(cec, ~0, HDMI_CEC_MASK);
+		dw_hdmi_write(cec, ~0, HDMI_IH_MUTE_CEC_STAT0);
+		dw_hdmi_write(cec, 0, HDMI_CEC_POLARITY);
+
+		cec->ops->disable(cec->hdmi);
+	} else {
+		unsigned irqs;
+
+		dw_hdmi_write(cec, 0, HDMI_CEC_CTRL);
+		dw_hdmi_write(cec, ~0, HDMI_IH_CEC_STAT0);
+		dw_hdmi_write(cec, 0, HDMI_CEC_LOCK);
+
+		dw_hdmi_cec_log_addr(cec->adap, CEC_LOG_ADDR_INVALID);
+
+		cec->ops->enable(cec->hdmi);
+
+		irqs = CEC_STAT_ERROR_INIT | CEC_STAT_NACK | CEC_STAT_EOM |
+		       CEC_STAT_DONE;
+		dw_hdmi_write(cec, irqs, HDMI_CEC_POLARITY);
+		dw_hdmi_write(cec, ~irqs, HDMI_CEC_MASK);
+		dw_hdmi_write(cec, ~irqs, HDMI_IH_MUTE_CEC_STAT0);
+	}
+	return 0;
+}
+
+static const struct cec_adap_ops dw_hdmi_cec_ops = {
+	.adap_enable = dw_hdmi_cec_enable,
+	.adap_log_addr = dw_hdmi_cec_log_addr,
+	.adap_transmit = dw_hdmi_cec_transmit,
+};
+
+static void dw_hdmi_cec_del(void *data)
+{
+	struct dw_hdmi_cec *cec = data;
+
+	cec_delete_adapter(cec->adap);
+}
+
+static int dw_hdmi_cec_probe(struct platform_device *pdev)
+{
+	struct dw_hdmi_cec_data *data = dev_get_platdata(&pdev->dev);
+	struct dw_hdmi_cec *cec;
+	int ret;
+
+	if (!data)
+		return -ENXIO;
+
+	/*
+	 * Our device is just a convenience - we want to link to the real
+	 * hardware device here, so that userspace can see the association
+	 * between the HDMI hardware and its associated CEC chardev.
+	 */
+	cec = devm_kzalloc(&pdev->dev, sizeof(*cec), GFP_KERNEL);
+	if (!cec)
+		return -ENOMEM;
+
+	cec->irq = data->irq;
+	cec->ops = data->ops;
+	cec->hdmi = data->hdmi;
+
+	platform_set_drvdata(pdev, cec);
+
+	dw_hdmi_write(cec, 0, HDMI_CEC_TX_CNT);
+	dw_hdmi_write(cec, ~0, HDMI_CEC_MASK);
+	dw_hdmi_write(cec, ~0, HDMI_IH_MUTE_CEC_STAT0);
+	dw_hdmi_write(cec, 0, HDMI_CEC_POLARITY);
+
+	cec->adap = cec_allocate_adapter(&dw_hdmi_cec_ops, cec, "dw_hdmi",
+					 CEC_CAP_LOG_ADDRS | CEC_CAP_TRANSMIT |
+					 CEC_CAP_RC, CEC_MAX_LOG_ADDRS);
+	if (IS_ERR(cec->adap))
+		return PTR_ERR(cec->adap);
+
+	/* override the module pointer */
+	cec->adap->owner = THIS_MODULE;
+
+	ret = devm_add_action(&pdev->dev, dw_hdmi_cec_del, cec);
+	if (ret) {
+		cec_delete_adapter(cec->adap);
+		return ret;
+	}
+
+	ret = devm_request_threaded_irq(&pdev->dev, cec->irq,
+					dw_hdmi_cec_hardirq,
+					dw_hdmi_cec_thread, IRQF_SHARED,
+					"dw-hdmi-cec", cec->adap);
+	if (ret < 0)
+		return ret;
+
+	cec->notify = cec_notifier_get(pdev->dev.parent);
+	if (!cec->notify)
+		return -ENOMEM;
+
+	ret = cec_register_adapter(cec->adap, pdev->dev.parent);
+	if (ret < 0) {
+		cec_notifier_put(cec->notify);
+		return ret;
+	}
+
+	/*
+	 * CEC documentation says we must not call cec_delete_adapter
+	 * after a successful call to cec_register_adapter().
+	 */
+	devm_remove_action(&pdev->dev, dw_hdmi_cec_del, cec);
+
+	cec_register_cec_notifier(cec->adap, cec->notify);
+
+	return 0;
+}
+
+static int dw_hdmi_cec_remove(struct platform_device *pdev)
+{
+	struct dw_hdmi_cec *cec = platform_get_drvdata(pdev);
+
+	cec_unregister_adapter(cec->adap);
+	cec_notifier_put(cec->notify);
+
+	return 0;
+}
+
+static struct platform_driver dw_hdmi_cec_driver = {
+	.probe	= dw_hdmi_cec_probe,
+	.remove	= dw_hdmi_cec_remove,
+	.driver = {
+		.name = "dw-hdmi-cec",
+	},
+};
+module_platform_driver(dw_hdmi_cec_driver);
+
+MODULE_AUTHOR("Russell King <rmk+kernel@armlinux.org.uk>");
+MODULE_DESCRIPTION("Synopsys Designware HDMI CEC driver for i.MX");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS(PLATFORM_MODULE_PREFIX "dw-hdmi-cec");
diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.h b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.h
new file mode 100644
index 000000000000..cf4dc121a2c4
--- /dev/null
+++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.h
@@ -0,0 +1,19 @@ 
+#ifndef DW_HDMI_CEC_H
+#define DW_HDMI_CEC_H
+
+struct dw_hdmi;
+
+struct dw_hdmi_cec_ops {
+	void (*write)(struct dw_hdmi *hdmi, u8 val, int offset);
+	u8 (*read)(struct dw_hdmi *hdmi, int offset);
+	void (*enable)(struct dw_hdmi *hdmi);
+	void (*disable)(struct dw_hdmi *hdmi);
+};
+
+struct dw_hdmi_cec_data {
+	struct dw_hdmi *hdmi;
+	const struct dw_hdmi_cec_ops *ops;
+	int irq;
+};
+
+#endif
diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
index b08cc0c95590..63386976501d 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
@@ -35,6 +35,7 @@ 
 
 #include "dw-hdmi.h"
 #include "dw-hdmi-audio.h"
+#include "dw-hdmi-cec.h"
 
 #include <media/cec-notifier.h>
 
@@ -133,6 +134,7 @@  struct dw_hdmi {
 	unsigned int version;
 
 	struct platform_device *audio;
+	struct platform_device *cec;
 	struct device *dev;
 	struct clk *isfr_clk;
 	struct clk *iahb_clk;
@@ -1794,7 +1796,6 @@  static void initialize_hdmi_ih_mutes(struct dw_hdmi *hdmi)
 	hdmi_writeb(hdmi, 0xff, HDMI_AUD_HBR_MASK);
 	hdmi_writeb(hdmi, 0xff, HDMI_GP_MASK);
 	hdmi_writeb(hdmi, 0xff, HDMI_A_APIINTMSK);
-	hdmi_writeb(hdmi, 0xff, HDMI_CEC_MASK);
 	hdmi_writeb(hdmi, 0xff, HDMI_I2CM_INT);
 	hdmi_writeb(hdmi, 0xff, HDMI_I2CM_CTLINT);
 
@@ -2236,6 +2237,29 @@  static int dw_hdmi_detect_phy(struct dw_hdmi *hdmi)
 	return -ENODEV;
 }
 
+static void dw_hdmi_cec_enable(struct dw_hdmi *hdmi)
+{
+	mutex_lock(&hdmi->mutex);
+	hdmi->mc_clkdis &= ~HDMI_MC_CLKDIS_CECCLK_DISABLE;
+	hdmi_writeb(hdmi, hdmi->mc_clkdis, HDMI_MC_CLKDIS);
+	mutex_unlock(&hdmi->mutex);
+}
+
+static void dw_hdmi_cec_disable(struct dw_hdmi *hdmi)
+{
+	mutex_lock(&hdmi->mutex);
+	hdmi->mc_clkdis |= HDMI_MC_CLKDIS_CECCLK_DISABLE;
+	hdmi_writeb(hdmi, hdmi->mc_clkdis, HDMI_MC_CLKDIS);
+	mutex_unlock(&hdmi->mutex);
+}
+
+static const struct dw_hdmi_cec_ops dw_hdmi_cec_ops = {
+	.write = hdmi_writeb,
+	.read = hdmi_readb,
+	.enable = dw_hdmi_cec_enable,
+	.disable = dw_hdmi_cec_disable,
+};
+
 static const struct regmap_config hdmi_regmap_8bit_config = {
 	.reg_bits	= 32,
 	.val_bits	= 8,
@@ -2258,6 +2282,7 @@  __dw_hdmi_probe(struct platform_device *pdev,
 	struct device_node *np = dev->of_node;
 	struct platform_device_info pdevinfo;
 	struct device_node *ddc_node;
+	struct dw_hdmi_cec_data cec;
 	struct dw_hdmi *hdmi;
 	struct resource *iores = NULL;
 	int irq;
@@ -2462,6 +2487,19 @@  __dw_hdmi_probe(struct platform_device *pdev,
 		hdmi->audio = platform_device_register_full(&pdevinfo);
 	}
 
+	if (config0 & HDMI_CONFIG0_CEC) {
+		cec.hdmi = hdmi;
+		cec.ops = &dw_hdmi_cec_ops;
+		cec.irq = irq;
+
+		pdevinfo.name = "dw-hdmi-cec";
+		pdevinfo.data = &cec;
+		pdevinfo.size_data = sizeof(cec);
+		pdevinfo.dma_mask = 0;
+
+		hdmi->cec = platform_device_register_full(&pdevinfo);
+	}
+
 	/* Reset HDMI DDC I2C master controller and mute I2CM interrupts */
 	if (hdmi->i2c)
 		dw_hdmi_i2c_init(hdmi);
@@ -2492,6 +2530,8 @@  static void __dw_hdmi_remove(struct dw_hdmi *hdmi)
 {
 	if (hdmi->audio && !IS_ERR(hdmi->audio))
 		platform_device_unregister(hdmi->audio);
+	if (!IS_ERR(hdmi->cec))
+		platform_device_unregister(hdmi->cec);
 
 	/* Disable all interrupts */
 	hdmi_writeb(hdmi, ~0, HDMI_IH_MUTE_PHY_STAT0);
diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.h b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.h
index c59f87e1483e..69644c83a0f8 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.h
+++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.h
@@ -555,6 +555,7 @@  enum {
 
 /* CONFIG0_ID field values */
 	HDMI_CONFIG0_I2S = 0x10,
+	HDMI_CONFIG0_CEC = 0x02,
 
 /* CONFIG1_ID field values */
 	HDMI_CONFIG1_AHB = 0x01,