On Tue, Dec 6, 2016 at 9:40 AM, Kevin Hilman <khilman@xxxxxxxxxxxx> wrote:
> Hans Verkuil <hverkuil@xxxxxxxxx> writes:
>
>> On 12/01/2016 10:16 AM, Laurent Pinchart wrote:
>>> Hello,
>>>
>>> On Thursday 01 Dec 2016 09:57:31 Sakari Ailus wrote:
>>>> On Wed, Nov 30, 2016 at 04:14:11PM -0800, Kevin Hilman wrote:
>>>>> Sakari Ailus <sakari.ailus@xxxxxx> writes:
>>>>>> On Wed, Nov 23, 2016 at 03:25:32PM -0800, Kevin Hilman wrote:
>>>>>>> Sakari Ailus <sakari.ailus@xxxxxx> 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)
>>>>>>>>> am437x-vpfe.c
>>>>>>>>>
>>>>>>>>> Signed-off-by: Kevin Hilman <khilman@xxxxxxxxxxxx>
>>>>>>>>> ---
>>>>>>>>>
>>>>>>>>> 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...
>>>
>>> That's really ugly :-( The problem should be fixed properly instead of adding
>>> one more offender.
>>
>> Do you have time for that, Laurent? I don't. Until that time we just need to
>> make do with this workaround.
>>
>>>
>>>>>>>>> #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;
>>>
>>> Can subdev_name be made const instead of blindly casting the full_name pointer
>>> ? If not this is probably unsafe, and if yes it should be done :-)
>>>
>>>>>>>>> + 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.
>>>>>>
>>>>>> Ack.
>>>>>>
>>>>>>>>> + 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.
>>>
>>> I'm afraid I have to disappoint Hans here, I don't have code for that yet.
>>>
>>>>>> I'm not sure that properly supporting connectors will provide any help
>>>>>> here.
>>>>>>
>>>>>> Looking at the s_routing() API, it's the calling driver that has to be
>>>>>> aware of sub-device specific function parameters. As such it's not a
>>>>>> very good idea to require that a driver is aware of the value range of
>>>>>> another driver's parameter. I wonder if a simple enumeration interface
>>>>>> would help here --- if I understand correctly, the purpose is just to
>>>>>> provide a way to choose the input using VIDIOC_S_INPUT.
>>>>>>
>>>>>> I guess that's somehow ok as long as you have no other combinations of
>>>>>> these devices but this is hardly future-proof. (And certainly not a
>>>>>> problem created by this patch.)
>>>>>
>>>>> Yeah, this is far from future proof.
>>>>>
>>>>>> It'd be still nice to fix that as presumably we don't have the option of
>>>>>> reworking how we expect the device tree to look like.
>>>>>
>>>>> Agreed.
>>>>>
>>>>> I'm just hoping someone can shed som light on "how we expect the device
>>>>> tree to look". ;)
>>>>
>>>> :-)
>>>>
>>>> For the tvp514x, do you need more than a single endpoint on the receiver
>>>> side? Does the input that's selected affect the bus parameters?
>>>>
>>>> If it doesn't, you could create a custom endpoint property for the possible
>>>> input values. The s_routing() really should be fixed though, but that could
>>>> be postponed I guess. There are quite a few drivers using it.
>>>
>>> There's two ways to look at s_routing() in my opinion, as the calling driver
>>> should really not hardcode any knowledge specific to a particular subdev. We
>>> can either have the calling driver discover the possible routing options at
>>> runtime through the subdev API, or modify the s_routing() API.
>>>
>>
>> Some historical perspective: s_routing was added well before the device tree
>> was ever used for ARM. And at that time the vast majority of drivers were PCI
>> or USB drivers, very few platform drivers existed (and those typically used
>> sensors, not video receivers).
>>
>> Before s_routing existed the situation was even worse.
>>
>> Basically what s_routing does is a poor-man's device tree entry, telling the
>> subdev how to route video or audio from connector to the output of the chip.
>> Typically the card tables in PCI or USB drivers contain the correct arguments
>> for s_routing. Of course, today we'd do that with the DT, but that was not an
>> option years ago.
>
> So I'm still confused on the path forward here.
>
> I do not have the time (or the V4L2 knowledge/experience) to rework the
> V4L2 internals to make this work, but I'm happy to test if someone else
> is working on it.
>
> In the meantime, what do we do with this series? I have a couple minor
> things to fixup based on review comments, but other than that, the
> s_routing decision is blocking this from getting an update for use on DT
> platforms.
>
> The alternative is to go the OMAP route for legacy drivers like this and
> just use pdata quirks for passing the legacy pdata (which has the input
> and output routes hard-coded in platform_data).
Also, FYI, I have the same issue with the output/display side of this
controller. It's using an I2C-connected adv7343, where the input and
output routes are configured by the driver using s_routing, and the
current code passes the routes in using platform_data.
Kevin
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