On 07.06.2019 06:45, Andrey Smirnov wrote:
> Transfer size of zero means a request to do an address-only
> transfer. Since the HW support this, we probably shouldn't be just
> ignoring such requests. While at it allow DP_AUX_I2C_MOT flag to pass
> through, since it is supported by the HW as well.
>
> Signed-off-by: Andrey Smirnov <andrew.smirnov@xxxxxxxxx>
Reviewed-by: Andrzej Hajda <a.hajda@xxxxxxxxxxx>
--
Regards
Andrzej
> Cc: Andrzej Hajda <a.hajda@xxxxxxxxxxx>
> Cc: Laurent Pinchart <Laurent.pinchart@xxxxxxxxxxxxxxxx>
> Cc: Tomi Valkeinen <tomi.valkeinen@xxxxxx>
> Cc: Andrey Gusakov <andrey.gusakov@xxxxxxxxxxxxxxxxxx>
> Cc: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
> Cc: Cory Tusar <cory.tusar@xxxxxxxx>
> Cc: Chris Healy <cphealy@xxxxxxxxx>
> Cc: Lucas Stach <l.stach@xxxxxxxxxxxxxx>
> Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> ---
> drivers/gpu/drm/bridge/tc358767.c | 30 +++++++++++++++++++++++-------
> 1 file changed, 23 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/tc358767.c b/drivers/gpu/drm/bridge/tc358767.c
> index 7d0fbb12195b..4bb9b15e1324 100644
> --- a/drivers/gpu/drm/bridge/tc358767.c
> +++ b/drivers/gpu/drm/bridge/tc358767.c
> @@ -145,6 +145,8 @@
>
> /* AUX channel */
> #define DP0_AUXCFG0 0x0660
> +#define DP0_AUXCFG0_BSIZE GENMASK(11, 8)
> +#define DP0_AUXCFG0_ADDR_ONLY BIT(4)
> #define DP0_AUXCFG1 0x0664
> #define AUX_RX_FILTER_EN BIT(16)
>
> @@ -327,6 +329,18 @@ static int tc_aux_read_data(struct tc_data *tc, void *data, size_t size)
> return size;
> }
>
> +static u32 tc_auxcfg0(struct drm_dp_aux_msg *msg, size_t size)
> +{
> + u32 auxcfg0 = msg->request;
> +
> + if (size)
> + auxcfg0 |= FIELD_PREP(DP0_AUXCFG0_BSIZE, size - 1);
> + else
> + auxcfg0 |= DP0_AUXCFG0_ADDR_ONLY;
> +
> + return auxcfg0;
> +}
> +
> static ssize_t tc_aux_transfer(struct drm_dp_aux *aux,
> struct drm_dp_aux_msg *msg)
> {
> @@ -336,9 +350,6 @@ static ssize_t tc_aux_transfer(struct drm_dp_aux *aux,
> u32 auxstatus;
> int ret;
>
> - if (size == 0)
> - return 0;
> -
> ret = tc_aux_wait_busy(tc, 100);
> if (ret)
> return ret;
> @@ -362,8 +373,7 @@ static ssize_t tc_aux_transfer(struct drm_dp_aux *aux,
> if (ret)
> return ret;
> /* Start transfer */
> - ret = regmap_write(tc->regmap, DP0_AUXCFG0,
> - ((size - 1) << 8) | request);
> + ret = regmap_write(tc->regmap, DP0_AUXCFG0, tc_auxcfg0(msg, size));
> if (ret)
> return ret;
>
> @@ -377,8 +387,14 @@ static ssize_t tc_aux_transfer(struct drm_dp_aux *aux,
>
> if (auxstatus & AUX_TIMEOUT)
> return -ETIMEDOUT;
> -
> - size = FIELD_GET(AUX_BYTES, auxstatus);
> + /*
> + * For some reason address-only DP_AUX_I2C_WRITE (MOT), still
> + * reports 1 byte transferred in its status. To deal we that
> + * we ignore aux_bytes field if we know that this was an
> + * address-only transfer
> + */
> + if (size)
> + size = FIELD_GET(AUX_BYTES, auxstatus);
> msg->reply = FIELD_GET(AUX_STATUS, auxstatus);
>
> switch (request) {
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