Hi Kevin,
On Tue, Dec 06, 2016 at 11:50:58AM -0800, Kevin Hilman wrote:
> 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.
A quick and dirty way to get forward would be to add a davinci specific
property to tell the valid arguments for the s_routing() in DT. That's quite
ugly, but would avoid adding a dependency to the tvp514x driver.
A better solution would be to provide the davinci driver with an enumeration
of which routes the tvp514x supports, a bit like the enum_mbus_code() pad op
does.
It'd be an additional sub-device operation next to s_routing(). The valid
values could be found that way. Only the tvp514x would need to support that
from the beginning so we'd know which values are valid here. If there's a
need to limit what should be actually allowed on that board it'd be found in
the tvp514x DT node, not davinci's.
There are many, many drivers using s_routing() so there would be a lot more
work in changing how s_routing() works. An enumeration of what's possible is
also a cleaner way to achieve what's needed IMO.
Laurent, Hans; let me know if you agree / disagree.
--
Kind regards,
Sakari Ailus
e-mail: sakari.ailus@xxxxxx XMPP: sailus@xxxxxxxxxxxxxx
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