Re: [PATCH 05/16] media: cadence: csi2rx: Add external DPHY support

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On 08/04/2021 11:13, Chunfeng Yun wrote:
On Wed, 2021-04-07 at 00:24 +0530, Pratyush Yadav wrote:
On 31/03/21 05:24PM, Chunfeng Yun wrote:
On Tue, 2021-03-30 at 23:03 +0530, 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@xxxxxx>
---
  drivers/media/platform/cadence/cdns-csi2rx.c | 147 +++++++++++++++++--
  1 file changed, 137 insertions(+), 10 deletions(-)

diff --git a/drivers/media/platform/cadence/cdns-csi2rx.c b/drivers/media/platform/cadence/cdns-csi2rx.c
index c68a3eac62cd..31bd80e3f780 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 +158,55 @@ 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;
+
+	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;
+
+	ret = phy_set_mode_ext(csi2rx->dphy, PHY_MODE_MIPI_DPHY,
+			       PHY_MIPI_DPHY_SUBMODE_RX);
+	if (ret)
+		return ret;
+
+	ret = phy_power_on(csi2rx->dphy);
+	if (ret)
+		return ret;
Seems phy_power_on, then phy_set_mode_ext?

Shouldn't the mode be set before the PHY is powered on so the correct
power on procedure can be performed based on the mode of operation?
Of course, it is fine for cnds-dphy.
But it depends on HW design and also phy driver;
if the mode is controlled in PHY IP register, we can't access it before
phy_power_on if no phy_init called (e.g. clock/power is not enabled).

Just let you pay attention on the phy sequence.

I don't think the phy configuration should depend on phy_power_on, but the runtime PM.

I guess this could be solved with:

phy_pm_runtime_get_sync();
phy_set_mode_ext();
phy_power_on();
phy_pm_runtime_put();

 Tomi



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