+additional lists
> I2C QUP driver relies on SMBus emulation support from the framework.
> To handle SMBus block reads, the driver should check I2C_M_RECV_LEN flag
> and should read the first byte received as the message length.
>
> The driver configures the QUP hardware to read one byte. Once the message
> length is known from this byte, the QUP hardware is configured to read the
> rest.
>
> Signed-off-by: Naveen Kaje <nkaje@xxxxxxxxxxxxxx>
> ---
> drivers/i2c/busses/i2c-qup.c | 95 ++++++++++++++++++++++++++++++-------
> -------
> 1 file changed, 66 insertions(+), 29 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-qup.c b/drivers/i2c/busses/i2c-qup.c
index
> ef31b26..2658b67 100644
> --- a/drivers/i2c/busses/i2c-qup.c
> +++ b/drivers/i2c/busses/i2c-qup.c
> @@ -526,38 +526,49 @@ static int qup_i2c_set_tags(u8 *tags, struct
> qup_i2c_dev *qup,
>
> int last = (qup->blk.pos == (qup->blk.count - 1)) && (qup->is_last);
>
> - if (qup->blk.pos == 0) {
> - tags[len++] = QUP_TAG_V2_START;
> - tags[len++] = addr & 0xff;
> + /* Handle SMBus block data read */
> + if ((msg->flags & I2C_M_RD) && (msg->flags & I2C_M_RECV_LEN)
> &&
> + (msg->len > 1)) {
> + tags[len++] = QUP_TAG_V2_DATARD_STOP;
> + data_len = qup_i2c_get_data_len(qup);
> + tags[len++] = data_len - 1;
> + } else {
> + if (qup->blk.pos == 0) {
> + tags[len++] = QUP_TAG_V2_START;
> + tags[len++] = addr & 0xff;
>
> - if (msg->flags & I2C_M_TEN)
> - tags[len++] = addr >> 8;
> - }
> + if (msg->flags & I2C_M_TEN)
> + tags[len++] = addr >> 8;
> + }
>
> - /* Send _STOP commands for the last block */
> - if (last) {
> - if (msg->flags & I2C_M_RD)
> - tags[len++] = QUP_TAG_V2_DATARD_STOP;
> - else
> - tags[len++] = QUP_TAG_V2_DATAWR_STOP;
> - } else {
> - if (msg->flags & I2C_M_RD)
> + /* Send _STOP commands for the last block */
> + if ((msg->flags & I2C_M_RD)
> + && (msg->flags & I2C_M_RECV_LEN)) {
> tags[len++] = QUP_TAG_V2_DATARD;
> - else
> - tags[len++] = QUP_TAG_V2_DATAWR;
> - }
> + } else if (last) {
> + if (msg->flags & I2C_M_RD)
> + tags[len++] = QUP_TAG_V2_DATARD_STOP;
> + else
> + tags[len++] = QUP_TAG_V2_DATAWR_STOP;
> + } else {
> + if (msg->flags & I2C_M_RD)
> + tags[len++] = QUP_TAG_V2_DATARD;
> + else
> + tags[len++] = QUP_TAG_V2_DATAWR;
> + }
>
> - data_len = qup_i2c_get_data_len(qup);
> + data_len = qup_i2c_get_data_len(qup);
>
> - /* 0 implies 256 bytes */
> - if (data_len == QUP_READ_LIMIT)
> - tags[len++] = 0;
> - else
> - tags[len++] = data_len;
> + /* 0 implies 256 bytes */
> + if (data_len == QUP_READ_LIMIT)
> + tags[len++] = 0;
> + else
> + tags[len++] = data_len;
>
> - if ((msg->flags & I2C_M_RD) && last && is_dma) {
> - tags[len++] = QUP_BAM_INPUT_EOT;
> - tags[len++] = QUP_BAM_FLUSH_STOP;
> + if ((msg->flags & I2C_M_RD) && last && is_dma) {
> + tags[len++] = QUP_BAM_INPUT_EOT;
> + tags[len++] = QUP_BAM_FLUSH_STOP;
> + }
> }
>
Will it look simpler if we add a qup_i2c_set_tags_smb instead and add an
Comment ? Here it is not clear how this is different from a normal read.
<snip..>
> +
> + /* Handle SMBus block read length */
> + if ((msg->flags & I2C_M_RECV_LEN) && (msg->len == 1)) {
> + if (msg->buf[0] > I2C_SMBUS_BLOCK_MAX) {
> + ret = -EPROTO;
> + goto err;
> + }
> + msg->len += msg->buf[0];
> + qup->pos = 0;
> + qup_i2c_set_read_mode_v2(qup, msg->len);
> + qup_i2c_issue_xfer_v2(qup, msg);
> + ret = qup_i2c_wait_for_complete(qup, msg);
> + if (ret)
> + goto err;
> + qup_i2c_set_blk_data(qup, msg);
> + }
> } while (qup->blk.pos < qup->blk.count);
When v2 mode is not supported this should return an error,
in qup_i2c_xfer for msg->flags & I2C_M_RECV_LEN
Regards,
Sricharan
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