[PATCH v7 04/13] media: cadence: csi2rx: Add external DPHY support

[Vaishnav Achath <vaishnav.a@ti.com>]

From: Pratyush Yadav <p.yadav@ti.com>

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.

Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
Signed-off-by: Vaishnav Achath <vaishnav.a@ti.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
---

Changes in v7:
- Fix multiplier and divider in v4l2_get_link_freq() which caused
  failures during streaming.

Changes in v6:
- Drop variable bpp and use fmt->bpp directly.
- Drop variable got_pm. Call phy_pm_runtime_put() unconditionally since
  it will just return an error if runtime PM is not enabled.
- Add Laurent's R-by.

Changes in v5:
- Only error out when phy_pm_runtime_get_sync() returns a negative
  value. A positive value can be returned if the phy was already
  resumed.
- Do not query the source subdev for format. Use the newly added
  internal format instead.

Changes in v4:
- Drop the call to set PHY submode. It is now being done via compatible
  on the DPHY side.

Changes in v3:
- Use v4l2_get_link_freq() to calculate pixel clock.

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 | 90 +++++++++++++++++---
 1 file changed, 80 insertions(+), 10 deletions(-)

diff --git a/drivers/media/platform/cadence/cdns-csi2rx.c b/drivers/media/platform/cadence/cdns-csi2rx.c
index ae3ebdb3890d..6933626adfc8 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)
@@ -137,6 +143,49 @@ 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;
+	const struct csi2rx_fmt *fmt;
+	s64 pixel_clock;
+	int ret;
+
+	fmt = csi2rx_get_fmt_by_code(csi2rx->fmt.code);
+
+	/*
+	 * Do not divide by the number of lanes here. That will be done by
+	 * phy_mipi_dphy_get_default_config().
+	 */
+	pixel_clock = v4l2_get_link_freq(csi2rx->source_subdev->ctrl_handler,
+					 fmt->bpp, 2 * csi2rx->num_lanes);
+	if (pixel_clock < 0)
+		return pixel_clock;
+
+	ret = phy_mipi_dphy_get_default_config(pixel_clock, 1, 1, cfg);
+	if (ret)
+		return ret;
+
+	ret = phy_pm_runtime_get_sync(csi2rx->dphy);
+	if (ret < 0 && ret != -ENOTSUPP)
+		return ret;
+
+	ret = phy_power_on(csi2rx->dphy);
+	if (ret)
+		goto out;
+
+	ret = phy_configure(csi2rx->dphy, &opts);
+	if (ret) {
+		/* Can't do anything if it fails. Ignore the return value. */
+		phy_power_off(csi2rx->dphy);
+		goto out;
+	}
+
+out:
+	phy_pm_runtime_put(csi2rx->dphy);
+	return ret;
+}
+
 static int csi2rx_start(struct csi2rx_priv *csi2rx)
 {
 	unsigned int i;
@@ -175,6 +224,17 @@ static int csi2rx_start(struct csi2rx_priv *csi2rx)
 	if (ret)
 		goto err_disable_pclk;
 
+	/* Enable DPHY clk and data lanes. */
+	if (csi2rx->dphy) {
+		reg = CSI2RX_DPHY_CL_EN | CSI2RX_DPHY_CL_RST;
+		for (i = 0; i < csi2rx->num_lanes; i++) {
+			reg |= CSI2RX_DPHY_DL_EN(csi2rx->lanes[i] - 1);
+			reg |= CSI2RX_DPHY_DL_RST(csi2rx->lanes[i] - 1);
+		}
+
+		writel(reg, csi2rx->base + CSI2RX_DPHY_LANE_CTRL_REG);
+	}
+
 	/*
 	 * Create a static mapping between the CSI virtual channels
 	 * and the output stream.
@@ -205,10 +265,21 @@ static int csi2rx_start(struct csi2rx_priv *csi2rx)
 	if (ret)
 		goto err_disable_pixclk;
 
+	if (csi2rx->dphy) {
+		ret = csi2rx_configure_external_dphy(csi2rx);
+		if (ret) {
+			dev_err(csi2rx->dev,
+				"Failed to configure external DPHY: %d\n", ret);
+			goto err_disable_sysclk;
+		}
+	}
+
 	clk_disable_unprepare(csi2rx->p_clk);
 
 	return 0;
 
+err_disable_sysclk:
+	clk_disable_unprepare(csi2rx->sys_clk);
 err_disable_pixclk:
 	for (; i > 0; i--)
 		clk_disable_unprepare(csi2rx->pixel_clk[i - 1]);
@@ -236,6 +307,13 @@ static void csi2rx_stop(struct csi2rx_priv *csi2rx)
 
 	if (v4l2_subdev_call(csi2rx->source_subdev, video, s_stream, false))
 		dev_warn(csi2rx->dev, "Couldn't disable our subdev\n");
+
+	if (csi2rx->dphy) {
+		writel(0, csi2rx->base + CSI2RX_DPHY_LANE_CTRL_REG);
+
+		if (phy_power_off(csi2rx->dphy))
+			dev_warn(csi2rx->dev, "Couldn't power off DPHY\n");
+	}
 }
 
 static int csi2rx_s_stream(struct v4l2_subdev *subdev, int enable)
@@ -432,15 +510,6 @@ static int csi2rx_get_resources(struct csi2rx_priv *csi2rx,
 		return PTR_ERR(csi2rx->dphy);
 	}
 
-	/*
-	 * FIXME: Once we'll have external D-PHY support, the check
-	 * will need to be removed.
-	 */
-	if (csi2rx->dphy) {
-		dev_err(&pdev->dev, "External D-PHY not supported yet\n");
-		return -EINVAL;
-	}
-
 	ret = clk_prepare_enable(csi2rx->p_clk);
 	if (ret) {
 		dev_err(&pdev->dev, "Couldn't prepare and enable P clock\n");
@@ -470,7 +539,7 @@ static int csi2rx_get_resources(struct csi2rx_priv *csi2rx,
 	 * FIXME: Once we'll have internal D-PHY support, the check
 	 * will need to be removed.
 	 */
-	if (csi2rx->has_internal_dphy) {
+	if (!csi2rx->dphy && csi2rx->has_internal_dphy) {
 		dev_err(&pdev->dev, "Internal D-PHY not supported yet\n");
 		return -EINVAL;
 	}
@@ -595,6 +664,7 @@ static int csi2rx_probe(struct platform_device *pdev)
 	dev_info(&pdev->dev,
 		 "Probed CSI2RX with %u/%u lanes, %u streams, %s D-PHY\n",
 		 csi2rx->num_lanes, csi2rx->max_lanes, csi2rx->max_streams,
+		 csi2rx->dphy ? "external" :
 		 csi2rx->has_internal_dphy ? "internal" : "no");
 
 	return 0;
-- 
2.17.1