Hi Sakari,
On Mon, May 18, 2020 at 12:45:18PM +0100, Kieran Bingham wrote:
> Hi Sakari,
>
> There are only fairly minor comments here, fix ups will be included in a
> v10.
>
> Is there anything major blocking integration?
>
> On 16/05/2020 22:51, Sakari Ailus wrote:
> > On Tue, May 12, 2020 at 04:51:03PM +0100, Kieran Bingham wrote:
> >
> > ...
> >
> >> +static int max9286_enum_mbus_code(struct v4l2_subdev *sd,
> >> + struct v4l2_subdev_pad_config *cfg,
> >> + struct v4l2_subdev_mbus_code_enum *code)
> >> +{
> >> + if (code->pad || code->index > 0)
> >> + return -EINVAL;
> >> +
> >> + code->code = MEDIA_BUS_FMT_UYVY8_2X8;
> >
> > Why UYVY8_2X8 and not UYVY8_1X16? In general, the single sample / pixel
> > variant of the format is generally used on the serial busses. This choice
> > was made when serial busses were introduced.
This is a bit of a tricky one. On the camera size, for the RDACM20, the
O10635 sensor outputs UYVY8_2X8. This if fed to the MAX9271 serializer,
which doesn't care about the data type. The MAX9271 has a 16-bit input
bus, with 10 bits reserved for data, 2 bits dynamically configurable
to carry H/V sync or extra data, and 4 bits dynamically configurable to
carry GPIOs or extra data. The 16-bit words are then serialized (it's a
bit more complicated, when using the H/V sync signals they are
transmitted in a different way, and the MAX9271 also supports a DDR mode
that makes the "serial link word" carry up to 30 bits). Effectively, the
two samples of UYVY8_2X8 are serialized in a 16-bit word each.
Sakari, with this information in mind, what would you recommend ?
> Ok - I presume this doesn't really have much effect anyway, they just
> have to match for the transmitter/receiver?
>
> But it makes sense to me, so I'll update to the 1x16 variant.
>
> >> +
> >> + return 0;
> >> +}
> >> +
> >> +static struct v4l2_mbus_framefmt *
> >> +max9286_get_pad_format(struct max9286_priv *priv,
> >> + struct v4l2_subdev_pad_config *cfg,
> >> + unsigned int pad, u32 which)
> >> +{
> >> + switch (which) {
> >> + case V4L2_SUBDEV_FORMAT_TRY:
> >> + return v4l2_subdev_get_try_format(&priv->sd, cfg, pad);
> >> + case V4L2_SUBDEV_FORMAT_ACTIVE:
> >> + return &priv->fmt[pad];
> >> + default:
> >> + return NULL;
> >> + }
> >> +}
> >> +
> >> +static int max9286_set_fmt(struct v4l2_subdev *sd,
> >> + struct v4l2_subdev_pad_config *cfg,
> >> + struct v4l2_subdev_format *format)
> >> +{
> >> + struct max9286_priv *priv = sd_to_max9286(sd);
> >> + struct v4l2_mbus_framefmt *cfg_fmt;
> >> +
> >> + if (format->pad >= MAX9286_SRC_PAD)
> >> + return -EINVAL;
> >
> > You can remove these checks; it's been already done by the caller.
> >
>
> Ok.
>
>
> > ...
> >
> >> +static int max9286_parse_dt(struct max9286_priv *priv)
> >> +{
> >> + struct device *dev = &priv->client->dev;
> >> + struct device_node *i2c_mux;
> >> + struct device_node *node = NULL;
> >> + unsigned int i2c_mux_mask = 0;
> >> +
> >> + of_node_get(dev->of_node);
> >> + i2c_mux = of_find_node_by_name(dev->of_node, "i2c-mux");
> >> + if (!i2c_mux) {
> >> + dev_err(dev, "Failed to find i2c-mux node\n");
> >> + of_node_put(dev->of_node);
> >> + return -EINVAL;
> >> + }
> >> +
> >> + /* Identify which i2c-mux channels are enabled */
> >> + for_each_child_of_node(i2c_mux, node) {
> >> + u32 id = 0;
> >> +
> >> + of_property_read_u32(node, "reg", &id);
> >> + if (id >= MAX9286_NUM_GMSL)
> >> + continue;
> >> +
> >> + if (!of_device_is_available(node)) {
> >> + dev_dbg(dev, "Skipping disabled I2C bus port %u\n", id);
> >> + continue;
> >> + }
> >> +
> >> + i2c_mux_mask |= BIT(id);
> >> + }
> >> + of_node_put(node);
> >> + of_node_put(i2c_mux);
> >> +
> >> + /* Parse the endpoints */
> >> + for_each_endpoint_of_node(dev->of_node, node) {
> >> + struct max9286_source *source;
> >> + struct of_endpoint ep;
> >> +
> >> + of_graph_parse_endpoint(node, &ep);
> >> + dev_dbg(dev, "Endpoint %pOF on port %d",
> >> + ep.local_node, ep.port);
> >> +
> >> + if (ep.port > MAX9286_NUM_GMSL) {
> >> + dev_err(dev, "Invalid endpoint %s on port %d",
> >> + of_node_full_name(ep.local_node), ep.port);
> >> + continue;
> >> + }
> >> +
> >> + /* For the source endpoint just parse the bus configuration. */
> >> + if (ep.port == MAX9286_SRC_PAD) {
> >> + struct v4l2_fwnode_endpoint vep = {
> >> + .bus_type = V4L2_MBUS_CSI2_DPHY
> >> + };
> >> + int ret;
> >> +
> >> + ret = v4l2_fwnode_endpoint_parse(
> >> + of_fwnode_handle(node), &vep);
> >> + if (ret) {
> >> + of_node_put(node);
> >> + of_node_put(dev->of_node);
> >> + return ret;
> >> + }
> >> +
> >> + if (vep.bus_type != V4L2_MBUS_CSI2_DPHY) {
> >
> > This won't happen, the bus type will stay if you set it to a non-zero
> > value.
>
>
> Ok - I'll remove this check.
>
>
> >
> >> + dev_err(dev,
> >> + "Media bus %u type not supported\n",
> >> + vep.bus_type);
> >> + v4l2_fwnode_endpoint_free(&vep);
> >> + of_node_put(node);
> >> + of_node_put(dev->of_node);
> >> + return -EINVAL;
> >> + }
> >> +
> >> + priv->csi2_data_lanes =
> >> + vep.bus.mipi_csi2.num_data_lanes;
> >> + v4l2_fwnode_endpoint_free(&vep);
> >
> > No need to call this unless you use v4l2_fwnode_endpoint_alloc_parse().
> >
> > And as you don't, you also won't know which frequencies are known to be
> > safe to use. That said, perhaps where this device is used having a random
> > frequency on that bus could not be an issue. Perhaps.
>
> Does this generate a range? or a list of static supported frequencies?
>
> We configure the pixel clock based upon the number of cameras connected,
> and their pixel rates etc ...
>
> Are you saying that the frequency of this clock should be validated to
> be a specific range? or are you talking about a different frequency?
>
>
> For now I'll remove the v4l2_fwnode_endpoint_alloc_parse().
>
>
>
> >> +
> >> + continue;
> >> + }
> >> +
> >> + /* Skip if the corresponding GMSL link is unavailable. */
> >> + if (!(i2c_mux_mask & BIT(ep.port)))
> >> + continue;
> >> +
> >> + if (priv->sources[ep.port].fwnode) {
> >> + dev_err(dev,
> >> + "Multiple port endpoints are not supported: %d",
> >> + ep.port);
> >> +
> >> + continue;
> >> + }
> >> +
> >> + source = &priv->sources[ep.port];
> >> + source->fwnode = fwnode_graph_get_remote_endpoint(
> >> + of_fwnode_handle(node));
> >> + if (!source->fwnode) {
> >> + dev_err(dev,
> >> + "Endpoint %pOF has no remote endpoint connection\n",
> >> + ep.local_node);
> >> +
> >> + continue;
> >> + }
> >> +
> >> + priv->source_mask |= BIT(ep.port);
> >> + priv->nsources++;
> >> + }
> >> + of_node_put(node);
> >> + of_node_put(dev->of_node);
> >> +
> >> + priv->route_mask = priv->source_mask;
> >> +
> >> + return 0;
> >> +}
> >
>
--
Regards,
Laurent Pinchart
