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

From: Vaishnav Achath
Date: Tue Mar 14 2023 - 07:56:25 EST


From: Pratyush Yadav <p.yadav@xxxxxx>

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@xxxxxx>
Signed-off-by: Vaishnav Achath <vaishnav.a@xxxxxx>
Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
---

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