On 21 September 2017 at 16:30, Philipp Zabel <p.zabel@xxxxxxxxxxxxxx> wrote:
> g_mbus_config was supposed to indicate all supported lane numbers, not
> only the number of those currently in active use. Since the TC358743
> can dynamically reduce the number of active lanes if the required
> bandwidth allows for it, report all lane numbers up to the connected
> number of lanes as supported in pdata mode.
> In device tree mode, do not report lane count and clock mode at all, as
> the receiver driver can determine these from the device tree.
>
> To allow communicating the number of currently active lanes, add a new
> bitfield to the v4l2_mbus_config flags. This is a temporary fix, to be
> used only until a better solution is found.
>
> Signed-off-by: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
Tested-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> ---
> Changes since v1:
> - Check csi_lanes_in_use <= num_data_lanes before writing to cfg.
> - Increase size of lane mask to 4 bits and always explicitly report
> number of lanes in use.
> - Clear clock and connected lane flags in DT mode.
> ---
> drivers/media/i2c/tc358743.c | 30 ++++++++++++++++--------------
> include/media/v4l2-mediabus.h | 8 ++++++++
> 2 files changed, 24 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/media/i2c/tc358743.c b/drivers/media/i2c/tc358743.c
> index e6f5c363ccab5..a35043cefe128 100644
> --- a/drivers/media/i2c/tc358743.c
> +++ b/drivers/media/i2c/tc358743.c
> @@ -1458,28 +1458,29 @@ static int tc358743_g_mbus_config(struct v4l2_subdev *sd,
> struct v4l2_mbus_config *cfg)
> {
> struct tc358743_state *state = to_state(sd);
> + const u32 mask = V4L2_MBUS_CSI2_LANE_MASK;
> +
> + if (state->csi_lanes_in_use > state->bus.num_data_lanes)
> + return -EINVAL;
>
> cfg->type = V4L2_MBUS_CSI2;
> + cfg->flags = (state->csi_lanes_in_use << __ffs(mask)) & mask;
>
> - /* Support for non-continuous CSI-2 clock is missing in the driver */
> - cfg->flags = V4L2_MBUS_CSI2_CONTINUOUS_CLOCK;
> + /* In DT mode, only report the number of active lanes */
> + if (sd->dev->of_node)
> + return 0;
>
> - switch (state->csi_lanes_in_use) {
> - case 1:
> + /* Support for non-continuous CSI-2 clock is missing in pdata mode */
> + cfg->flags |= V4L2_MBUS_CSI2_CONTINUOUS_CLOCK;
> +
> + if (state->bus.num_data_lanes > 0)
> cfg->flags |= V4L2_MBUS_CSI2_1_LANE;
> - break;
> - case 2:
> + if (state->bus.num_data_lanes > 1)
> cfg->flags |= V4L2_MBUS_CSI2_2_LANE;
> - break;
> - case 3:
> + if (state->bus.num_data_lanes > 2)
> cfg->flags |= V4L2_MBUS_CSI2_3_LANE;
> - break;
> - case 4:
> + if (state->bus.num_data_lanes > 3)
> cfg->flags |= V4L2_MBUS_CSI2_4_LANE;
> - break;
> - default:
> - return -EINVAL;
> - }
>
> return 0;
> }
> @@ -1885,6 +1886,7 @@ static int tc358743_probe(struct i2c_client *client,
> if (pdata) {
> state->pdata = *pdata;
> state->bus.flags = V4L2_MBUS_CSI2_CONTINUOUS_CLOCK;
> + state->bus.num_data_lanes = 4;
> } else {
> err = tc358743_probe_of(state);
> if (err == -ENODEV)
> diff --git a/include/media/v4l2-mediabus.h b/include/media/v4l2-mediabus.h
> index 93f8afcb7a220..fc106c902bf47 100644
> --- a/include/media/v4l2-mediabus.h
> +++ b/include/media/v4l2-mediabus.h
> @@ -63,6 +63,14 @@
> V4L2_MBUS_CSI2_3_LANE | V4L2_MBUS_CSI2_4_LANE)
> #define V4L2_MBUS_CSI2_CHANNELS (V4L2_MBUS_CSI2_CHANNEL_0 | V4L2_MBUS_CSI2_CHANNEL_1 | \
> V4L2_MBUS_CSI2_CHANNEL_2 | V4L2_MBUS_CSI2_CHANNEL_3)
> +/*
> + * Number of lanes in use, 0 == use all available lanes (default)
> + *
> + * This is a temporary fix for devices that need to reduce the number of active
> + * lanes for certain modes, until g_mbus_config() can be replaced with a better
> + * solution.
> + */
> +#define V4L2_MBUS_CSI2_LANE_MASK (0xf << 10)
>
> /**
> * enum v4l2_mbus_type - media bus type
> --
> 2.11.0
>
