Simplify AUX data write by dropping index arithmetic and shifting and replacing it with a call to a helper function that does two things:
1. Copies user-provided data into a write buffer 2. Transfers contents of the write buffer to up to 4 32-bit registers on the chip
Note that separate data endianness fix:
tmp = (tmp << 8) | buf[i];
that was reserved for DP_AUX_I2C_WRITE looks really strange, since it will place data differently depending on the passed user-data size. E.g. for a write of 1 byte, data transferred to the chip would look like:
[byte0] [dummy1] [dummy2] [dummy3]
whereas for a write of 4 bytes we'd get:
[byte3] [byte2] [byte1] [byte0]
Since there's no indication in the datasheet that I2C write buffer should be treated differently than AUX write buffer and no comment in the original code explaining why it was done this way, that special I2C write buffer transformation was dropped in this patch.
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 | 48 +++++++++++++++++-------------- 1 file changed, 26 insertions(+), 22 deletions(-)
diff --git a/drivers/gpu/drm/bridge/tc358767.c b/drivers/gpu/drm/bridge/tc358767.c index 02f6d907f5c4..a441e8e66287 100644 --- a/drivers/gpu/drm/bridge/tc358767.c +++ b/drivers/gpu/drm/bridge/tc358767.c @@ -321,6 +321,21 @@ static int tc_aux_get_status(struct tc_data *tc, u8 *reply) return 0; }
+static int tc_aux_write_data(struct tc_data *tc, const void *data, + size_t size) +{ + u32 auxwdata[DP_AUX_MAX_PAYLOAD_BYTES / sizeof(u32)] = { 0 }; + int ret, count = ALIGN(size, sizeof(u32)); + + memcpy(auxwdata, data, size); + + ret = regmap_raw_write(tc->regmap, DP0_AUXWDATA(0), auxwdata, count); + if (ret) + return ret; + + return size; +} + static int tc_aux_read_data(struct tc_data *tc, void *data, size_t size) { u32 auxrdata[DP_AUX_MAX_PAYLOAD_BYTES / sizeof(u32)]; @@ -341,9 +356,6 @@ static ssize_t tc_aux_transfer(struct drm_dp_aux *aux, struct tc_data *tc = aux_to_tc(aux); size_t size = min_t(size_t, 8, msg->size); u8 request = msg->request & ~DP_AUX_I2C_MOT; - u8 *buf = msg->buffer; - u32 tmp = 0; - int i = 0; int ret;
if (size == 0) @@ -353,25 +365,17 @@ static ssize_t tc_aux_transfer(struct drm_dp_aux *aux, if (ret) return ret;
- if (request == DP_AUX_I2C_WRITE || request == DP_AUX_NATIVE_WRITE) { - /* Store data */ - while (i < size) { - if (request == DP_AUX_NATIVE_WRITE) - tmp = tmp | (buf[i] << (8 * (i & 0x3))); - else - tmp = (tmp << 8) | buf[i]; - i++; - if (((i % 4) == 0) || (i == size)) { - ret = regmap_write(tc->regmap, - DP0_AUXWDATA((i - 1) >> 2), - tmp); - if (ret) - return ret; - tmp = 0; - } - } - } else if (request != DP_AUX_I2C_READ && - request != DP_AUX_NATIVE_READ) { + switch (request) { + case DP_AUX_NATIVE_READ: + case DP_AUX_I2C_READ: + 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; + break; + default: return -EINVAL; }