media: imx6-mipi-csi2: Call remote subdev get_mbus_config to get active lanes

Currently, the CSI2 subdevice is using the data-lanes from the
neareast endpoint to config the CSI2 lanes.

While this may work, the proper way to configure the hardware is
to obtain the remote subdevice in v4l2_async_notifier_operations.bound(),
and then call get_mbus_config using the remote subdevice to get
the active lanes.

Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

diff --git a/drivers/staging/media/imx/imx6-mipi-csi2.c b/drivers/staging/media/imx/imx6-mipi-csi2.c
index 94d87d27d38962e620c4f27c1cafabc9c15f3ef0..6b58899dcefe15442be0101cfd494a7f2bb066e9 100644 (file)
--- a/drivers/staging/media/imx/imx6-mipi-csi2.c
+++ b/drivers/staging/media/imx/imx6-mipi-csi2.c
@@ -42,7 +42,10 @@ struct csi2_dev {
        struct clk             *pllref_clk;
        struct clk             *pix_clk; /* what is this? */
        void __iomem           *base;
-       struct v4l2_fwnode_bus_mipi_csi2 bus;
+
+       struct v4l2_subdev      *remote;
+       unsigned int            remote_pad;
+       unsigned short          data_lanes;
 
        /* lock to protect all members below */
        struct mutex lock;
@@ -138,10 +141,8 @@ static void csi2_enable(struct csi2_dev *csi2, bool enable)
        }
 }
 
-static void csi2_set_lanes(struct csi2_dev *csi2)
+static void csi2_set_lanes(struct csi2_dev *csi2, unsigned int lanes)
 {
-       int lanes = csi2->bus.num_data_lanes;
-
        writel(lanes - 1, csi2->base + CSI2_N_LANES);
 }
 
@@ -250,13 +251,12 @@ static int __maybe_unused csi2_dphy_wait_ulp(struct csi2_dev *csi2)
 }
 
 /* Waits for low-power LP-11 state on data and clock lanes. */
-static void csi2_dphy_wait_stopstate(struct csi2_dev *csi2)
+static void csi2_dphy_wait_stopstate(struct csi2_dev *csi2, unsigned int lanes)
 {
        u32 mask, reg;
        int ret;
 
-       mask = PHY_STOPSTATECLK | (((1 << csi2->bus.num_data_lanes) - 1) <<
-                                  PHY_STOPSTATEDATA_BIT);
+       mask = PHY_STOPSTATECLK | (((1 << lanes) - 1) << PHY_STOPSTATEDATA_BIT);
 
        ret = readl_poll_timeout(csi2->base + CSI2_PHY_STATE, reg,
                                 (reg & mask) == mask, 0, 500000);
@@ -300,8 +300,65 @@ static void csi2ipu_gasket_init(struct csi2_dev *csi2)
        writel(reg, csi2->base + CSI2IPU_GASKET);
 }
 
+static int csi2_get_active_lanes(struct csi2_dev *csi2, unsigned int *lanes)
+{
+       struct v4l2_mbus_config mbus_config = { 0 };
+       unsigned int num_lanes = UINT_MAX;
+       int ret;
+
+       *lanes = csi2->data_lanes;
+
+       ret = v4l2_subdev_call(csi2->remote, pad, get_mbus_config,
+                              csi2->remote_pad, &mbus_config);
+       if (ret == -ENOIOCTLCMD) {
+               dev_dbg(csi2->dev, "No remote mbus configuration available\n");
+               return 0;
+       }
+
+       if (ret) {
+               dev_err(csi2->dev, "Failed to get remote mbus configuration\n");
+               return ret;
+       }
+
+       if (mbus_config.type != V4L2_MBUS_CSI2_DPHY) {
+               dev_err(csi2->dev, "Unsupported media bus type %u\n",
+                       mbus_config.type);
+               return -EINVAL;
+       }
+
+       switch (mbus_config.flags & V4L2_MBUS_CSI2_LANES) {
+       case V4L2_MBUS_CSI2_1_LANE:
+               num_lanes = 1;
+               break;
+       case V4L2_MBUS_CSI2_2_LANE:
+               num_lanes = 2;
+               break;
+       case V4L2_MBUS_CSI2_3_LANE:
+               num_lanes = 3;
+               break;
+       case V4L2_MBUS_CSI2_4_LANE:
+               num_lanes = 4;
+               break;
+       default:
+               num_lanes = csi2->data_lanes;
+               break;
+       }
+
+       if (num_lanes > csi2->data_lanes) {
+               dev_err(csi2->dev,
+                       "Unsupported mbus config: too many data lanes %u\n",
+                       num_lanes);
+               return -EINVAL;
+       }
+
+       *lanes = num_lanes;
+
+       return 0;
+}
+
 static int csi2_start(struct csi2_dev *csi2)
 {
+       unsigned int lanes;
        int ret;
 
        ret = clk_prepare_enable(csi2->pix_clk);
@@ -316,12 +373,16 @@ static int csi2_start(struct csi2_dev *csi2)
        if (ret)
                goto err_disable_clk;
 
+       ret = csi2_get_active_lanes(csi2, &lanes);
+       if (ret)
+               goto err_disable_clk;
+
        /* Step 4 */
-       csi2_set_lanes(csi2);
+       csi2_set_lanes(csi2, lanes);
        csi2_enable(csi2, true);
 
        /* Step 5 */
-       csi2_dphy_wait_stopstate(csi2);
+       csi2_dphy_wait_stopstate(csi2, lanes);
 
        /* Step 6 */
        ret = v4l2_subdev_call(csi2->src_sd, video, s_stream, 1);
@@ -544,12 +605,35 @@ static int csi2_notify_bound(struct v4l2_async_notifier *notifier,
 {
        struct csi2_dev *csi2 = notifier_to_dev(notifier);
        struct media_pad *sink = &csi2->sd.entity.pads[CSI2_SINK_PAD];
+       int pad;
+
+       pad = media_entity_get_fwnode_pad(&sd->entity, asd->match.fwnode,
+                                         MEDIA_PAD_FL_SOURCE);
+       if (pad < 0) {
+               dev_err(csi2->dev, "Failed to find pad for %s\n", sd->name);
+               return pad;
+       }
+
+       csi2->remote = sd;
+       csi2->remote_pad = pad;
+
+       dev_dbg(csi2->dev, "Bound %s pad: %d\n", sd->name, pad);
 
        return v4l2_create_fwnode_links_to_pad(sd, sink);
 }
 
+static void csi2_notify_unbind(struct v4l2_async_notifier *notifier,
+                              struct v4l2_subdev *sd,
+                              struct v4l2_async_subdev *asd)
+{
+       struct csi2_dev *csi2 = notifier_to_dev(notifier);
+
+       csi2->remote = NULL;
+}
+
 static const struct v4l2_async_notifier_operations csi2_notify_ops = {
        .bound = csi2_notify_bound,
+       .unbind = csi2_notify_unbind,
 };
 
 static int csi2_async_register(struct csi2_dev *csi2)
@@ -572,10 +656,10 @@ static int csi2_async_register(struct csi2_dev *csi2)
        if (ret)
                goto err_parse;
 
-       csi2->bus = vep.bus.mipi_csi2;
+       csi2->data_lanes = vep.bus.mipi_csi2.num_data_lanes;
 
-       dev_dbg(csi2->dev, "data lanes: %d\n", csi2->bus.num_data_lanes);
-       dev_dbg(csi2->dev, "flags: 0x%08x\n", csi2->bus.flags);
+       dev_dbg(csi2->dev, "data lanes: %d\n", vep.bus.mipi_csi2.num_data_lanes);
+       dev_dbg(csi2->dev, "flags: 0x%08x\n", vep.bus.mipi_csi2.flags);
 
        asd = kzalloc(sizeof(*asd), GFP_KERNEL);
        if (!asd) {