linux-kernel - Re: [PATCH v2 3/6] media: ov5647: Add support for non-continuous clock mode

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Message-ID: <20200622083501.htr7mzngchyn7n7q@uno.localdomain>
Date:   Mon, 22 Jun 2020 10:35:01 +0200
From:   Jacopo Mondi <jacopo@...ndi.org>
To:     Roman Kovalivskyi <roman.kovalivskyi@...ballogic.com>
Cc:     Sakari Ailus <sakari.ailus@...ux.intel.com>,
        linux-kernel@...r.kernel.org, linux-media@...r.kernel.org,
        linux-renesas-soc@...r.kernel.org,
        Luis Oliveira <lolivei@...opsys.com>,
        Niklas Söderlund <niklas.soderlund@...natech.se>,
        Michael Rodin <mrodin@...adit-jv.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Hugues Fruchet <hugues.fruchet@...com>,
        Maxime Ripard <mripard@...nel.org>,
        Adam Ford <aford173@...il.com>,
        Todor Tomov <todor.tomov@...aro.org>,
        Suresh Udipi <sudipi@...adit-jv.com>,
        Andrew Gabbasov <andrew_gabbasov@...tor.com>,
        Eugeniu Rosca <erosca@...adit-jv.com>,
        Dave Stevenson <dave.stevenson@...pberrypi.org>
Subject: Re: [PATCH v2 3/6] media: ov5647: Add support for non-continuous
 clock mode

Hi Roman,

On Mon, Jun 22, 2020 at 10:00:46AM +0300, Roman Kovalivskyi wrote:
> Hi Jacopo,
>
> On 18.06.20 13:13, Jacopo Mondi wrote:
> > Hi Roman, Sakari
> >
> > On Tue, May 19, 2020 at 02:57:07PM +0300, Sakari Ailus wrote:
> >> Hi Roman,
> >>
> >> On Tue, May 19, 2020 at 04:16:18AM +0300, Roman Kovalivskyi wrote:
> >>> From: Dave Stevenson <dave.stevenson@...pberrypi.org>
> >>>
> >>> The driver was only supporting continuous clock mode
> >>> although this was not stated anywhere.
> >>> Non-continuous clock saves a small amount of power and
> >>> on some SoCs is easier to interface with.
> >>>
> > not much to add to what Sakari said, apart for
> >
> >>> Signed-off-by: Dave Stevenson <dave.stevenson@...pberrypi.org>
> >>> Signed-off-by: Roman Kovalivskyi <roman.kovalivskyi@...ballogic.com>
> >>> ---
> >>>  drivers/media/i2c/ov5647.c | 25 ++++++++++++++++++++++---
> >>>  1 file changed, 22 insertions(+), 3 deletions(-)
> >>>
> >>> diff --git a/drivers/media/i2c/ov5647.c b/drivers/media/i2c/ov5647.c
> >>> index 796cc80f8ee1..10f35c637f91 100644
> >>> --- a/drivers/media/i2c/ov5647.c
> >>> +++ b/drivers/media/i2c/ov5647.c
> >>> @@ -44,6 +44,7 @@
> >>>  #define PWDN_ACTIVE_DELAY_MS	20
> >>>
> >>>  #define MIPI_CTRL00_CLOCK_LANE_GATE		BIT(5)
> >>> +#define MIPI_CTRL00_LINE_SYNC_ENABLE		BIT(4)
> >>>  #define MIPI_CTRL00_BUS_IDLE			BIT(2)
> >>>  #define MIPI_CTRL00_CLOCK_LANE_DISABLE		BIT(0)
> >>>
> >>> @@ -95,6 +96,7 @@ struct ov5647 {
> >>>  	int				power_count;
> >>>  	struct clk			*xclk;
> >>>  	struct gpio_desc		*pwdn;
> >>> +	bool				is_clock_contiguous;
> > the clock is 'continuous' not contigous :)
> >
> > I plan to upport more ov5647 patches soon, Roman are you planning a
> > resend of this series or should I do so (keeping your signoffs of
> > course)
> >
> > Thanks
> >   j
>
> I would be grateful if someone more competent would continue with this
> patch series, so feel free to update it with v3.

I think you did a very good job, I just happen to have a bit more time
to dedicate to this.

I'll make sure I'll cc you and the cc list from your series.

Thanks
  j

>
> >>>  };
> >>>
> >>>  static inline struct ov5647 *to_state(struct v4l2_subdev *sd)
> >>> @@ -274,9 +276,15 @@ static int ov5647_set_virtual_channel(struct v4l2_subdev *sd, int channel)
> >>>
> >>>  static int ov5647_stream_on(struct v4l2_subdev *sd)
> >>>  {
> >>> +	struct ov5647 *ov5647 = to_state(sd);
> >>> +	u8 val = MIPI_CTRL00_BUS_IDLE;
> >>>  	int ret;
> >>>
> >>> -	ret = ov5647_write(sd, OV5647_REG_MIPI_CTRL00, MIPI_CTRL00_BUS_IDLE);
> >>> +	if (ov5647->is_clock_contiguous)
> >>> +		val |= MIPI_CTRL00_CLOCK_LANE_GATE |
> >>> +		       MIPI_CTRL00_LINE_SYNC_ENABLE;
> >>> +
> >>> +	ret = ov5647_write(sd, OV5647_REG_MIPI_CTRL00, val);
> >>>  	if (ret < 0)
> >>>  		return ret;
> >>>
> >>> @@ -573,7 +581,7 @@ static const struct v4l2_subdev_internal_ops ov5647_subdev_internal_ops = {
> >>>  	.open = ov5647_open,
> >>>  };
> >>>
> >>> -static int ov5647_parse_dt(struct device_node *np)
> >>> +static int ov5647_parse_dt(struct ov5647 *sensor, struct device_node *np)
> >>>  {
> >>>  	struct v4l2_fwnode_endpoint bus_cfg = { .bus_type = 0 };
> >>>  	struct device_node *ep;
> >>> @@ -586,6 +594,17 @@ static int ov5647_parse_dt(struct device_node *np)
> >>>
> >>>  	ret = v4l2_fwnode_endpoint_parse(of_fwnode_handle(ep), &bus_cfg);
> >>>
> >> Extra newline.
> >>
> >>> +	if (!ret) {
> >>> +		of_node_put(ep);
> >>> +		of_node_put(np);
> >> Why to put np as well?
> >>
> >>> +		return ret;
> >> Please add a label at the end; it makes error handling easier.
> >>
> >>> +	}
> >>> +
> >>> +	if (bus_cfg.bus_type == V4L2_MBUS_CSI2_DPHY
> >>> +		|| bus_cfg.bus_type == V4L2_MBUS_CSI2_CPHY)
> >> I bet this device is D-PHY only.
> >>
> >>> +		sensor->is_clock_contiguous = bus_cfg.bus.mipi_csi2.flags
> >>> +			& V4L2_MBUS_CSI2_NONCONTINUOUS_CLOCK;
> >> Now that you're making use of bus specific parameters, please set the bus
> >> type first before calling v4l2_fwnode_endpoint_parse().
> >>
> >>> +
> >>>  	of_node_put(ep);
> >>>  	return ret;
> >>>  }
> >>> @@ -604,7 +623,7 @@ static int ov5647_probe(struct i2c_client *client)
> >>>  		return -ENOMEM;
> >>>
> >>>  	if (IS_ENABLED(CONFIG_OF) && np) {
> >>> -		ret = ov5647_parse_dt(np);
> >>> +		ret = ov5647_parse_dt(sensor, np);
> >>>  		if (ret) {
> >>>  			dev_err(dev, "DT parsing error: %d\n", ret);
> >>>  			return ret;
> >> --
> >> Kind regards,
> >>
> >> Sakari Ailus
>
>
> --
>
> Best regards,
> Roman Kovalivskyi
>