On 03/02/2017 10:42 AM, Kamal Dasu wrote:
> 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.
Do you mind adding:
Fixes: dd1aa2524bc5 ("i2c: brcmstb: Add Broadcom settop SoC i2c
controller driver")
so this can be backported to -stable tree as well? Thanks!
>
>> 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
>
--
Florian
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