linux-kernel - Re: [PATCH v2 06/18] media: cadence: csi2rx: Add external DPHY support

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Date:   Fri, 28 May 2021 13:00:40 +0530
From:   Pratyush Yadav <p.yadav@...com>
To:     Tomi Valkeinen <tomi.valkeinen@...asonboard.com>
CC:     Maxime Ripard <mripard@...nel.org>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Kishon Vijay Abraham I <kishon@...com>,
        Vinod Koul <vkoul@...nel.org>,
        Peter Ujfalusi <peter.ujfalusi@...il.com>,
        Steve Longerbeam <slongerbeam@...il.com>,
        Benoit Parrot <bparrot@...com>, <linux-media@...r.kernel.org>,
        <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-phy@...ts.infradead.org>, <dmaengine@...r.kernel.org>,
        Vignesh Raghavendra <vigneshr@...com>,
        Chunfeng Yun <chunfeng.yun@...iatek.com>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>
Subject: Re: [PATCH v2 06/18] media: cadence: csi2rx: Add external DPHY
 support

On 28/05/21 10:23AM, Tomi Valkeinen wrote:
> On 26/05/2021 18:22, Pratyush Yadav wrote:
> > Some platforms like TI's J721E can have the CSI2RX paired with an
> > external DPHY. Add support to enable and configure the DPHY using the
> > generic PHY framework.
> > 
> > Get the pixel rate and bpp from the subdev and pass them on to the DPHY
> > along with the number of lanes. All other settings are left to their
> > default values.
> > 
> > Signed-off-by: Pratyush Yadav <p.yadav@...com>
> > 
> > ---
> > 
> > Changes in v2:
> > - Use phy_pm_runtime_get_sync() and phy_pm_runtime_put() before making
> >    calls to set PHY mode, etc. to make sure it is ready.
> > 
> >   drivers/media/platform/cadence/cdns-csi2rx.c | 158 +++++++++++++++++--
> >   1 file changed, 148 insertions(+), 10 deletions(-)
> > 
> > diff --git a/drivers/media/platform/cadence/cdns-csi2rx.c b/drivers/media/platform/cadence/cdns-csi2rx.c
> > index c68a3eac62cd..459326de2eff 100644
> > --- a/drivers/media/platform/cadence/cdns-csi2rx.c
> > +++ b/drivers/media/platform/cadence/cdns-csi2rx.c
> > @@ -30,6 +30,12 @@
> >   #define CSI2RX_STATIC_CFG_DLANE_MAP(llane, plane)	((plane) << (16 + (llane) * 4))
> >   #define CSI2RX_STATIC_CFG_LANES_MASK			GENMASK(11, 8)
> > +#define CSI2RX_DPHY_LANE_CTRL_REG		0x40
> > +#define CSI2RX_DPHY_CL_RST			BIT(16)
> > +#define CSI2RX_DPHY_DL_RST(i)			BIT((i) + 12)
> > +#define CSI2RX_DPHY_CL_EN			BIT(4)
> > +#define CSI2RX_DPHY_DL_EN(i)			BIT(i)
> > +
> >   #define CSI2RX_STREAM_BASE(n)		(((n) + 1) * 0x100)
> >   #define CSI2RX_STREAM_CTRL_REG(n)		(CSI2RX_STREAM_BASE(n) + 0x000)
> > @@ -54,6 +60,11 @@ enum csi2rx_pads {
> >   	CSI2RX_PAD_MAX,
> >   };
> > +struct csi2rx_fmt {
> > +	u32				code;
> > +	u8				bpp;
> > +};
> > +
> >   struct csi2rx_priv {
> >   	struct device			*dev;
> >   	unsigned int			count;
> > @@ -85,6 +96,52 @@ struct csi2rx_priv {
> >   	int				source_pad;
> >   };
> > +static const struct csi2rx_fmt formats[] = {
> > +	{
> > +		.code	= MEDIA_BUS_FMT_YUYV8_2X8,
> > +		.bpp	= 16,
> > +	},
> > +	{
> > +		.code	= MEDIA_BUS_FMT_UYVY8_2X8,
> > +		.bpp	= 16,
> > +	},
> > +	{
> > +		.code	= MEDIA_BUS_FMT_YVYU8_2X8,
> > +		.bpp	= 16,
> > +	},
> > +	{
> > +		.code	= MEDIA_BUS_FMT_VYUY8_2X8,
> > +		.bpp	= 16,
> > +	},
> > +};
> > +
> > +static u8 csi2rx_get_bpp(u32 code)
> > +{
> > +	int i;
> > +
> > +	for (i = 0; i < ARRAY_SIZE(formats); i++) {
> > +		if (formats[i].code == code)
> > +			return formats[i].bpp;
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +static s64 csi2rx_get_pixel_rate(struct csi2rx_priv *csi2rx)
> > +{
> > +	struct v4l2_ctrl *ctrl;
> > +
> > +	ctrl = v4l2_ctrl_find(csi2rx->source_subdev->ctrl_handler,
> > +			      V4L2_CID_PIXEL_RATE);
> > +	if (!ctrl) {
> > +		dev_err(csi2rx->dev, "no pixel rate control in subdev: %s\n",
> > +			csi2rx->source_subdev->name);
> > +		return -EINVAL;
> > +	}
> > +
> > +	return v4l2_ctrl_g_ctrl_int64(ctrl);
> > +}
> > +
> >   static inline
> >   struct csi2rx_priv *v4l2_subdev_to_csi2rx(struct v4l2_subdev *subdev)
> >   {
> > @@ -101,6 +158,66 @@ static void csi2rx_reset(struct csi2rx_priv *csi2rx)
> >   	writel(0, csi2rx->base + CSI2RX_SOFT_RESET_REG);
> >   }
> > +static int csi2rx_configure_external_dphy(struct csi2rx_priv *csi2rx)
> > +{
> > +	union phy_configure_opts opts = { };
> > +	struct phy_configure_opts_mipi_dphy *cfg = &opts.mipi_dphy;
> > +	struct v4l2_subdev_format sd_fmt;
> > +	s64 pixel_rate;
> > +	int ret;
> > +	u8 bpp;
> > +	bool got_pm = true;
> > +
> > +	sd_fmt.which = V4L2_SUBDEV_FORMAT_ACTIVE;
> > +	sd_fmt.pad = 0;
> > +
> > +	ret = v4l2_subdev_call(csi2rx->source_subdev, pad, get_fmt, NULL,
> > +			       &sd_fmt);
> > +	if (ret)
> > +		return ret;
> > +
> > +	bpp = csi2rx_get_bpp(sd_fmt.format.code);
> > +	if (!bpp)
> > +		return -EINVAL;
> > +
> > +	pixel_rate = csi2rx_get_pixel_rate(csi2rx);
> > +	if (pixel_rate < 0)
> > +		return pixel_rate;
> > +
> > +	ret = phy_mipi_dphy_get_default_config(pixel_rate, bpp,
> > +					       csi2rx->num_lanes, cfg);
> > +	if (ret)
> > +		return ret;
> 
> I guess the above code works for now, but with multiple streams it won't.
> There's no (single) pixel rate or bpp with multiple streams, and the link
> freq is the one that needs to be used. There's v4l2_get_link_freq() helper
> which makes it easier to support both pixel rate and link freq.

Ok. I will use it instead. The less changes needed when adding 
multistream support the better.

-- 
Regards,
Pratyush Yadav
Texas Instruments Inc.