Re: [PATCH v3 3/4] [media] davinci: vpif_capture: get subdevs from DT

[Kevin Hilman <khilman-rdvid1DuHRBWk0Htik3J/w@public.gmane.org>]

Hi Sakari,

Sakari Ailus <sakari.ailus-X3B1VOXEql0@public.gmane.org> writes:

> On Tue, Nov 22, 2016 at 07:52:43AM -0800, Kevin Hilman wrote:
>> Allow getting of subdevs from DT ports and endpoints.
>> 
>> The _get_pdata() function was larely inspired by (i.e. stolen from)
>
> vpif_capture_get_pdata and "largely"?

Yes, thanks.

>> am437x-vpfe.c
>> 
>> Signed-off-by: Kevin Hilman <khilman-rdvid1DuHRBWk0Htik3J/w@public.gmane.org>
>> ---
>>  drivers/media/platform/davinci/vpif_capture.c | 130 +++++++++++++++++++++++++-
>>  include/media/davinci/vpif_types.h            |   9 +-
>>  2 files changed, 133 insertions(+), 6 deletions(-)
>> 
>> diff --git a/drivers/media/platform/davinci/vpif_capture.c b/drivers/media/platform/davinci/vpif_capture.c
>> index 94ee6cf03f02..47a4699157e7 100644
>> --- a/drivers/media/platform/davinci/vpif_capture.c
>> +++ b/drivers/media/platform/davinci/vpif_capture.c
>> @@ -26,6 +26,8 @@
>>  #include <linux/slab.h>
>>  
>>  #include <media/v4l2-ioctl.h>
>> +#include <media/v4l2-of.h>
>> +#include <media/i2c/tvp514x.h>
>
> Do you need this header?
>

Yes, based on discussion with Hans, since there is no DT binding for
selecting the input pins of the TVP514x, I have to select it in the
driver, so I need the defines from this header.  More on this below...

>>  
>>  #include "vpif.h"
>>  #include "vpif_capture.h"
>> @@ -650,6 +652,10 @@ static int vpif_input_to_subdev(
>>  
>>  	vpif_dbg(2, debug, "vpif_input_to_subdev\n");
>>  
>> +	if (!chan_cfg)
>> +		return -1;
>> +	if (input_index >= chan_cfg->input_count)
>> +		return -1;
>>  	subdev_name = chan_cfg->inputs[input_index].subdev_name;
>>  	if (subdev_name == NULL)
>>  		return -1;
>> @@ -657,7 +663,7 @@ static int vpif_input_to_subdev(
>>  	/* loop through the sub device list to get the sub device info */
>>  	for (i = 0; i < vpif_cfg->subdev_count; i++) {
>>  		subdev_info = &vpif_cfg->subdev_info[i];
>> -		if (!strcmp(subdev_info->name, subdev_name))
>> +		if (subdev_info && !strcmp(subdev_info->name, subdev_name))
>>  			return i;
>>  	}
>>  	return -1;
>> @@ -1327,6 +1333,21 @@ static int vpif_async_bound(struct v4l2_async_notifier *notifier,
>>  {
>>  	int i;
>>  
>> +	for (i = 0; i < vpif_obj.config->asd_sizes[0]; i++) {
>> +		struct v4l2_async_subdev *_asd = vpif_obj.config->asd[i];
>> +		const struct device_node *node = _asd->match.of.node;
>> +
>> +		if (node == subdev->of_node) {
>> +			vpif_obj.sd[i] = subdev;
>> +			vpif_obj.config->chan_config->inputs[i].subdev_name =
>> +				(char *)subdev->of_node->full_name;
>> +			vpif_dbg(2, debug,
>> +				 "%s: setting input %d subdev_name = %s\n",
>> +				 __func__, i, subdev->of_node->full_name);
>> +			return 0;
>> +		}
>> +	}
>> +
>>  	for (i = 0; i < vpif_obj.config->subdev_count; i++)
>>  		if (!strcmp(vpif_obj.config->subdev_info[i].name,
>>  			    subdev->name)) {
>> @@ -1422,6 +1443,110 @@ static int vpif_async_complete(struct v4l2_async_notifier *notifier)
>>  	return vpif_probe_complete();
>>  }
>>  
>> +static struct vpif_capture_config *
>> +vpif_capture_get_pdata(struct platform_device *pdev)
>> +{
>> +	struct device_node *endpoint = NULL;
>> +	struct v4l2_of_endpoint bus_cfg;
>> +	struct vpif_capture_config *pdata;
>> +	struct vpif_subdev_info *sdinfo;
>> +	struct vpif_capture_chan_config *chan;
>> +	unsigned int i;
>> +
>> +	dev_dbg(&pdev->dev, "vpif_get_pdata\n");
>> +
>> +	if (!IS_ENABLED(CONFIG_OF) || !pdev->dev.of_node)
>> +		return pdev->dev.platform_data;
>> +
>> +	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
>> +	if (!pdata)
>> +		return NULL;
>> +	pdata->subdev_info =
>> +		devm_kzalloc(&pdev->dev, sizeof(*pdata->subdev_info) *
>> +			     VPIF_CAPTURE_MAX_CHANNELS, GFP_KERNEL);
>> +
>> +	if (!pdata->subdev_info)
>> +		return NULL;
>> +	dev_dbg(&pdev->dev, "%s\n", __func__);
>> +
>> +	for (i = 0; ; i++) {
>> +		struct device_node *rem;
>> +		unsigned int flags;
>> +		int err;
>> +
>> +		endpoint = of_graph_get_next_endpoint(pdev->dev.of_node,
>> +						      endpoint);
>> +		if (!endpoint)
>> +			break;
>> +
>> +		sdinfo = &pdata->subdev_info[i];
>
> subdev_info[] has got VPIF_CAPTURE_MAX_CHANNELS entries only.
>

Right, I need to make the loop only go for a max of
VPIF_CAPTURE_MAX_CHANNELS iterations.

>> +		chan = &pdata->chan_config[i];
>> +		chan->inputs = devm_kzalloc(&pdev->dev,
>> +					    sizeof(*chan->inputs) *
>> +					    VPIF_DISPLAY_MAX_CHANNELS,
>> +					    GFP_KERNEL);
>> +
>> +		chan->input_count++;
>> +		chan->inputs[i].input.type = V4L2_INPUT_TYPE_CAMERA;
>
> I wonder what's the purpose of using index i on this array as well.

The number of endpoints in DT is the number of input channels configured
(up to a max of VPIF_CAPTURE_MAX_CHANNELS.)

> If you use that to access a corresponding entry in a different array, I'd
> just create a struct that contains the port configuration and the async
> sub-device. The omap3isp driver does that, for instance; see
> isp_of_parse_nodes() in drivers/media/platform/omap3isp/isp.c if you're
> interested. Up to you.

OK, I'll have a look at that driver. The goal here with this series is
just to get this working with DT, but also not break the existing legacy
platform_device support, so I'm trying not to mess with the
driver-interal data structures too much.

>> +		chan->inputs[i].input.std = V4L2_STD_ALL;
>> +		chan->inputs[i].input.capabilities = V4L2_IN_CAP_STD;
>> +
>> +		/* FIXME: need a new property? ch0:composite ch1: s-video */
>> +		if (i == 0)
>
> Can you assume that the first endopoint has got a particular kind of input?
> What if it's not connected?

On all the boards I know of (there aren't many using this SoC), it's a
safe assumption.

> If this is a different physical port (not in the meaning another) in the
> device, I'd use the reg property for this. Please see
> Documentation/devicetree/bindings/media/video-interfaces.txt .

My understanding (which is admittedly somewhat fuzzy) of the TVP514x is
that it's not physically a different port.  Instead, it's just telling
the TVP514x which pin(s) will be active inputs (and what kind of signal
will be present.)

I'm open to a better way to describe this input select from DT, but
based on what I heard from Hans, there isn't currently a good way to do
that except for in the driver:
(c.f. https://marc.info/?l=linux-arm-kernel&m=147887871615788)

Based on further discussion in that thread, it sounds like there may be
a way forward coming soon, and I'll be glad to switch to that when it
arrives.

>> +			chan->inputs[i].input_route = INPUT_CVBS_VI2B;
>> +		else
>> +			chan->inputs[i].input_route = INPUT_SVIDEO_VI2C_VI1C;
>> +		chan->inputs[i].output_route = OUTPUT_10BIT_422_EMBEDDED_SYNC;
>> +
>> +		err = v4l2_of_parse_endpoint(endpoint, &bus_cfg);
>> +		if (err) {
>> +			dev_err(&pdev->dev, "Could not parse the endpoint\n");
>> +			goto done;
>> +		}
>> +		dev_dbg(&pdev->dev, "Endpoint %s, bus_width = %d\n",
>> +			endpoint->full_name, bus_cfg.bus.parallel.bus_width);
>> +		flags = bus_cfg.bus.parallel.flags;
>> +
>> +		if (flags & V4L2_MBUS_HSYNC_ACTIVE_HIGH)
>> +			chan->vpif_if.hd_pol = 1;
>> +
>> +		if (flags & V4L2_MBUS_VSYNC_ACTIVE_HIGH)
>> +			chan->vpif_if.vd_pol = 1;
>> +
>> +		chan->vpif_if.if_type = VPIF_IF_BT656;
>> +		rem = of_graph_get_remote_port_parent(endpoint);
>> +		if (!rem) {
>> +			dev_dbg(&pdev->dev, "Remote device at %s not found\n",
>> +				endpoint->full_name);
>> +			goto done;
>> +		}
>> +
>> +		dev_dbg(&pdev->dev, "Remote device %s, %s found\n",
>> +			rem->name, rem->full_name);
>> +		sdinfo->name = rem->full_name;
>> +
>> +		pdata->asd[i] = devm_kzalloc(&pdev->dev,
>> +					     sizeof(struct v4l2_async_subdev),
>> +					     GFP_KERNEL);
>
> Do you ensure somewhere that i isn't overrunning the pdata->asd[] array?
> It's got VPIF_CAPTURE_MAX_CHANNELS entries.

Oops, no.  That will be fixed by making the outer for loop only iterate
for i = i..VPIF_CAPTURE_MAX_CHANNELS.


Thanks for the review,

Kevin
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