Jaedon,
On Fri, Aug 12, 2016 at 1:56 AM, Jaedon Shin <jaedon.shin@xxxxxxxxx> wrote:
> Fixes always repeated START when process multiple bytes with a message
> in combined transactions.
>
> The BSC has multiple data stroage that send or receive data at once, and
> it has the RESTART, NOSTART, NOSTOP to the condition flags. The problem
> is that begin repeated START for all the messages in combined
> transaction. If length of a data is over 32bytes, The BSC transmit
> repeated START in every 32bytes.
>
Can you rephrase the commit message to something like below ?
The BSC data buffers to send and receive data are each of size 32 bytes
or 8 bytes 'xfersz' depending on SoC. The problem observed for all the
combined message transfer was if length of data transfer was a multiple of
'xfersz' a repeated START was being transmitted by BSC driver. Fixed this
by appropriately setting START/STOP conditions for such transfers.
> Fixes always repeated START when process multiple bytes with a message
> in combined transactions.
>
> The BSC has multiple data stroage that send or receive data at once, and
> it has the RESTART, NOSTART, NOSTOP to the condition flags. The problem
> is that begin repeated START for all the messages in combined
> transaction. If length of a data is over 32bytes, The BSC transmit
> repeated START in every 32bytes.
The changes looks good to me.
> Signed-off-by: Jaedon Shin <jaedon.shin@xxxxxxxxx>
> ---
> drivers/i2c/busses/i2c-brcmstb.c | 27 +++++++++++++++++++++------
> 1 file changed, 21 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-brcmstb.c b/drivers/i2c/busses/i2c-brcmstb.c
> index 3f5a4d71d3bf..51c5f0bd361d 100644
> --- a/drivers/i2c/busses/i2c-brcmstb.c
> +++ b/drivers/i2c/busses/i2c-brcmstb.c
> @@ -465,6 +465,7 @@ static int brcmstb_i2c_xfer(struct i2c_adapter *adapter,
> u8 *tmp_buf;
> int len = 0;
> int xfersz = brcmstb_i2c_get_xfersz(dev);
> + u32 cond, cond_per_msg;
>
> if (dev->is_suspended)
> return -EBUSY;
> @@ -481,10 +482,11 @@ static int brcmstb_i2c_xfer(struct i2c_adapter *adapter,
> pmsg->buf ? pmsg->buf[0] : '0', pmsg->len);
>
> if (i < (num - 1) && (msgs[i + 1].flags & I2C_M_NOSTART))
> - brcmstb_set_i2c_start_stop(dev, ~(COND_START_STOP));
> + cond = ~COND_START_STOP;
> else
> - brcmstb_set_i2c_start_stop(dev,
> - COND_RESTART | COND_NOSTOP);
> + cond = COND_RESTART | COND_NOSTOP;
> +
> + brcmstb_set_i2c_start_stop(dev, cond);
>
> /* Send slave address */
> if (!(pmsg->flags & I2C_M_NOSTART)) {
> @@ -497,13 +499,24 @@ static int brcmstb_i2c_xfer(struct i2c_adapter *adapter,
> }
> }
>
> + cond_per_msg = cond;
> +
> /* Perform data transfer */
> while (len) {
> bytes_to_xfer = min(len, xfersz);
>
> - if (len <= xfersz && i == (num - 1))
> - brcmstb_set_i2c_start_stop(dev,
> - ~(COND_START_STOP));
> + if (len <= xfersz) {
> + if (i == (num - 1))
> + cond_per_msg = cond_per_msg &
> + ~(COND_RESTART | COND_NOSTOP);
> + else
> + cond_per_msg = cond;
> + } else {
> + cond_per_msg = (cond_per_msg & ~COND_RESTART) |
> + COND_NOSTOP;
> + }
> +
> + brcmstb_set_i2c_start_stop(dev, cond_per_msg);
>
> rc = brcmstb_i2c_xfer_bsc_data(dev, tmp_buf,
> bytes_to_xfer, pmsg);
> @@ -512,6 +525,8 @@ static int brcmstb_i2c_xfer(struct i2c_adapter *adapter,
>
> len -= bytes_to_xfer;
> tmp_buf += bytes_to_xfer;
> +
> + cond_per_msg = COND_NOSTART | COND_NOSTOP;
> }
> }
>
> --
> 2.9.2
>
Thanks
Kamal
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