On Fri, February 26, 2016 9:28 pm, Sricharan R wrote:
> After the addition of V2 support, there was a regression observed
> when testing it on MSM8996. The reason is driver puts the controller
> in to RUN state and writes the data to be 'tx' ed in fifo. But controller
> has to be put in to 'PAUSE' state and data has to written to fifo. Then
> should be put in to 'RUN' state separately.
>
> Signed-off-by: Sricharan R <sricha...@codeaurora.org>
Tested-by: Pramod Gurav <gpra...@codeaurora.org>
Regards,
Pramod
> ---
> drivers/i2c/busses/i2c-qup.c | 46
> +++++++++++++++++++++++++++++++++++++-------
> 1 file changed, 39 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-qup.c b/drivers/i2c/busses/i2c-qup.c
> index 30f3a2b..23eaabb 100644
> --- a/drivers/i2c/busses/i2c-qup.c
> +++ b/drivers/i2c/busses/i2c-qup.c
> @@ -372,6 +372,38 @@ static void qup_i2c_set_write_mode(struct qup_i2c_dev
> *qup, struct i2c_msg *msg)
> }
> }
>
> +static int check_for_fifo_space(struct qup_i2c_dev *qup)
> +{
> + int ret;
> +
> + ret = qup_i2c_change_state(qup, QUP_PAUSE_STATE);
> + if (ret)
> + goto out;
> +
> + ret = qup_i2c_wait_ready(qup, QUP_OUT_FULL,
> + RESET_BIT, 4 * ONE_BYTE);
> + if (ret) {
> + /* Fifo is full. Drain out the fifo */
> + ret = qup_i2c_change_state(qup, QUP_RUN_STATE);
> + if (ret)
> + goto out;
> +
> + ret = qup_i2c_wait_ready(qup, QUP_OUT_NOT_EMPTY,
> + RESET_BIT, 256 * ONE_BYTE);
> + if (ret) {
> + dev_err(qup->dev, "timeout for fifo out full");
> + goto out;
> + }
> +
> + ret = qup_i2c_change_state(qup, QUP_PAUSE_STATE);
> + if (ret)
> + goto out;
> + }
> +
> +out:
> + return ret;
> +}
> +
> static int qup_i2c_issue_write(struct qup_i2c_dev *qup, struct i2c_msg
> *msg)
> {
> u32 addr = msg->addr << 1;
> @@ -390,8 +422,7 @@ static int qup_i2c_issue_write(struct qup_i2c_dev
> *qup, struct i2c_msg *msg)
>
> while (qup->pos < msg->len) {
> /* Check that there's space in the FIFO for our pair */
> - ret = qup_i2c_wait_ready(qup, QUP_OUT_FULL, RESET_BIT,
> - 4 * ONE_BYTE);
> + ret = check_for_fifo_space(qup);
> if (ret)
> return ret;
>
> @@ -413,6 +444,8 @@ static int qup_i2c_issue_write(struct qup_i2c_dev
> *qup, struct i2c_msg *msg)
> idx++;
> }
>
> + ret = qup_i2c_change_state(qup, QUP_RUN_STATE);
> +
> return ret;
> }
>
> @@ -441,12 +474,9 @@ static int qup_i2c_send_data(struct qup_i2c_dev *qup,
> int tlen, u8 *tbuf,
> int ret = 0;
>
> while (len > 0) {
> - ret = qup_i2c_wait_ready(qup, QUP_OUT_FULL,
> - RESET_BIT, 4 * ONE_BYTE);
> - if (ret) {
> - dev_err(qup->dev, "timeout for fifo out full");
> + ret = check_for_fifo_space(qup);
> + if (ret)
> return ret;
> - }
>
> t = (len >= 4) ? 4 : len;
>
> @@ -465,6 +495,8 @@ static int qup_i2c_send_data(struct qup_i2c_dev *qup,
> int tlen, u8 *tbuf,
> len -= 4;
> }
>
> + ret = qup_i2c_change_state(qup, QUP_RUN_STATE);
> +
> return ret;
> }
>
> --
> QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
> of Code Aurora Forum, hosted by The Linux Foundation
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-ker...@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>
Pramod
--
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a Linux Foundation Collaborative Project
