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@gmail.com Reviewed-by: Andrzej Hajda a.hajda@samsung.com Cc: Andrzej Hajda a.hajda@samsung.com Cc: Laurent Pinchart Laurent.pinchart@ideasonboard.com Cc: Tomi Valkeinen tomi.valkeinen@ti.com Cc: Andrey Gusakov andrey.gusakov@cogentembedded.com Cc: Philipp Zabel p.zabel@pengutronix.de Cc: Cory Tusar cory.tusar@zii.aero Cc: Chris Healy cphealy@gmail.com Cc: Lucas Stach l.stach@pengutronix.de Cc: dri-devel@lists.freedesktop.org Cc: linux-kernel@vger.kernel.org --- drivers/gpu/drm/bridge/tc358767.c | 42 +++++++++++++++++++++++-------- 1 file changed, 31 insertions(+), 11 deletions(-)
diff --git a/drivers/gpu/drm/bridge/tc358767.c b/drivers/gpu/drm/bridge/tc358767.c index 3f8a15390813..7b8e19d6cf29 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)
@@ -326,6 +328,18 @@ 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) { @@ -335,9 +349,6 @@ 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); if (ret) return ret; @@ -348,9 +359,11 @@ static ssize_t tc_aux_transfer(struct drm_dp_aux *aux, break; case DP_AUX_NATIVE_WRITE: case DP_AUX_I2C_WRITE: - ret = tc_aux_write_data(tc, msg->buffer, size); - if (ret < 0) - return ret; + if (size) { + ret = tc_aux_write_data(tc, msg->buffer, size); + if (ret < 0) + return ret; + } break; default: return -EINVAL; @@ -361,8 +374,7 @@ 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;
@@ -376,14 +388,22 @@ 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) { case DP_AUX_NATIVE_READ: case DP_AUX_I2C_READ: - return tc_aux_read_data(tc, msg->buffer, size); + if (size) + return tc_aux_read_data(tc, msg->buffer, size); + break; }
return size;