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> 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) { -- 2.21.0 _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel