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Message-ID: <CA+V-a8utQjTb44wuAOS7+GVKMwvv+OpPTFZ5Ons9Tj=i0KCqzw@mail.gmail.com>
Date: Mon, 10 Aug 2020 08:25:02 +0100
From: "Lad, Prabhakar" <prabhakar.csengg@...il.com>
To: Jacopo Mondi <jacopo@...ndi.org>
Cc: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>,
Mauro Carvalho Chehab <mchehab@...nel.org>,
Rob Herring <robh+dt@...nel.org>,
Hans Verkuil <hverkuil-cisco@...all.nl>,
Kieran Bingham <kieran.bingham+renesas@...asonboard.com>,
Sakari Ailus <sakari.ailus@...ux.intel.com>,
linux-media <linux-media@...r.kernel.org>,
"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
<devicetree@...r.kernel.org>, LKML <linux-kernel@...r.kernel.org>,
Biju Das <biju.das.jz@...renesas.com>,
Linux-Renesas <linux-renesas-soc@...r.kernel.org>
Subject: Re: [PATCH v2 2/3] media: i2c: ov772x: Add support for BT656 mode
Hi Jacopo,
Thank you for the review.
On Thu, Aug 6, 2020 at 3:41 PM Jacopo Mondi <jacopo@...ndi.org> wrote:
>
> On Mon, Aug 03, 2020 at 12:39:12PM +0100, Lad Prabhakar wrote:
> > Add support to read the bus-type and enable BT656 mode if needed.
> >
> > The driver defaults to parallel mode if bus-type is not specified in DT.
> >
> > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
> > Reviewed-by: Biju Das <biju.das.jz@...renesas.com>
> > ---
> > drivers/media/i2c/ov772x.c | 40 ++++++++++++++++++++++++++++++++++++++
> > 1 file changed, 40 insertions(+)
> >
> > diff --git a/drivers/media/i2c/ov772x.c b/drivers/media/i2c/ov772x.c
> > index 2cc6a678069a..2de9248e3689 100644
> > --- a/drivers/media/i2c/ov772x.c
> > +++ b/drivers/media/i2c/ov772x.c
> > @@ -31,6 +31,7 @@
> > #include <media/v4l2-ctrls.h>
> > #include <media/v4l2-device.h>
> > #include <media/v4l2-event.h>
> > +#include <media/v4l2-fwnode.h>
> > #include <media/v4l2-image-sizes.h>
> > #include <media/v4l2-subdev.h>
> >
> > @@ -434,6 +435,7 @@ struct ov772x_priv {
> > #ifdef CONFIG_MEDIA_CONTROLLER
> > struct media_pad pad;
> > #endif
> > + struct v4l2_fwnode_endpoint ep;
> > };
> >
> > /*
> > @@ -574,6 +576,7 @@ static int ov772x_s_stream(struct v4l2_subdev *sd, int enable)
> > {
> > struct i2c_client *client = v4l2_get_subdevdata(sd);
> > struct ov772x_priv *priv = to_ov772x(sd);
> > + unsigned int val;
> > int ret = 0;
> >
> > mutex_lock(&priv->lock);
> > @@ -581,6 +584,22 @@ static int ov772x_s_stream(struct v4l2_subdev *sd, int enable)
> > if (priv->streaming == enable)
> > goto done;
> >
> > + if (priv->ep.bus_type == V4L2_MBUS_BT656 && enable) {
> > + ret = regmap_read(priv->regmap, COM7, &val);
> > + if (ret)
> > + goto done;
> > + val |= ITU656_ON_OFF;
> > + ret = regmap_write(priv->regmap, COM7, val);
> > + } else if (priv->ep.bus_type == V4L2_MBUS_BT656 && !enable) {
>
> is the !enable intentional ? (sorry I don't have access to the sensor
> manual). If not, see below:
>
> > + ret = regmap_read(priv->regmap, COM7, &val);
> > + if (ret)
> > + goto done;
> > + val &= ~ITU656_ON_OFF;
> > + ret = regmap_write(priv->regmap, COM7, val);
> > + }
> > + if (ret)
> > + goto done;
>
> Could you write this as:
>
Agreed will do.
> static int ov772x_s_stream(struct v4l2_subdev *sd, int enable)
> {
> struct i2c_client *client = v4l2_get_subdevdata(sd);
> struct ov772x_priv *priv = to_ov772x(sd);
> int ret = 0;
>
> mutex_lock(&priv->lock);
>
> if (priv->streaming == enable)
> goto done;
>
> if (enable) {
> ret = regmap_read(priv->regmap, COM7, &val);
> if (ret)
> goto done;
>
> if (priv->ep.bus_type == V4L2_MBUS_BT656)
> val |= ITU656_ON_OFF;
> else /* if you accept my suggestion to consider othe
> bus types as errors */
> val &= ~ITU656_ON_OFF;
>
> ret = regmap_write(priv->regmap, COM7, val);
> if (ret)
> goto done;
>
> dev_dbg(&client->dev, "format %d, win %s\n",
> priv->cfmt->code, priv->win->name);
> }
>
> ret = regmap_update_bits(priv->regmap, COM2, SOFT_SLEEP_MODE,
> enable ? 0 : SOFT_SLEEP_MODE);
> if (ret)
> goto done;
> priv->streaming = enable;
>
> done:
> mutex_unlock(&priv->lock);
>
> return ret;
> }
>
>
> > ret = regmap_update_bits(priv->regmap, COM2, SOFT_SLEEP_MODE,
> > enable ? 0 : SOFT_SLEEP_MODE);
> > if (ret)
> > @@ -1354,6 +1373,7 @@ static const struct v4l2_subdev_ops ov772x_subdev_ops = {
> >
> > static int ov772x_probe(struct i2c_client *client)
> > {
> > + struct fwnode_handle *endpoint;
> > struct ov772x_priv *priv;
> > int ret;
> > static const struct regmap_config ov772x_regmap_config = {
> > @@ -1415,6 +1435,26 @@ static int ov772x_probe(struct i2c_client *client)
> > goto error_clk_put;
> > }
> >
> > + endpoint = fwnode_graph_get_next_endpoint(dev_fwnode(&client->dev),
> > + NULL);
> > + if (!endpoint) {
> > + dev_err(&client->dev, "endpoint node not found\n");
> > + ret = -EINVAL;
> > + goto error_clk_put;
> > + }
> > +
> > + ret = v4l2_fwnode_endpoint_parse(endpoint, &priv->ep);
> > + fwnode_handle_put(endpoint);
> > + if (ret) {
> > + dev_err(&client->dev, "Could not parse endpoint\n");
> > + goto error_clk_put;
> > + }
> > +
> > + /* fallback to parallel mode */
> > + if (priv->ep.bus_type != V4L2_MBUS_PARALLEL &&
> > + priv->ep.bus_type != V4L2_MBUS_BT656)
> > + priv->ep.bus_type = V4L2_MBUS_PARALLEL;
>
> shouldn't this be an error ? It's either the bus type has not been
> specified on DT (which is fine, otherwise old DTB without that
> properties will fail) and the bus identification routine implemented
> in v4l2_fwnode_endpoint_parse() detected a bus type which is not
> supported, hence the DT properties are wrong, and this should be an
> error. If you plan to expand the parsing routine to support, say
> bus-width and pclk polarity please break this out to a new function.
>
Agreed.
Cheers,
Prabhakar
> Thanks
> j
>
> > +
> > ret = ov772x_video_probe(priv);
> > if (ret < 0)
> > goto error_gpio_put;
> > --
> > 2.17.1
> >
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