Hi Kamal, Florian,
> On 3 Mar 2017, at 3:48 AM, Florian Fainelli <f.fainelli@xxxxxxxxx> wrote:
>
> 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.
>>
No problem.
>>> 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")
>
Add that also.
Thanks,
Jaedon
> 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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