[PATCHv9 14/15] cec: s5p-cec: Add s5p-cec driver

[Kamil Debski]

Hi,

On 12 October 2015 at 14:39, Hans Verkuil <hverkuil at xs4all.nl> wrote:
> On 10/12/2015 02:33 PM, Kamil Debski wrote:
>> Hi,
>>
>> On 12 October 2015 at 12:50, Hans Verkuil <hverkuil at xs4all.nl> wrote:
>>> On 10/06/2015 12:32 AM, Russell King - ARM Linux wrote:
>>>> On Mon, Sep 07, 2015 at 03:44:43PM +0200, Hans Verkuil wrote:
>>>>> +    if (status & CEC_STATUS_TX_DONE) {
>>>>> +            if (status & CEC_STATUS_TX_ERROR) {
>>>>> +                    dev_dbg(cec->dev, "CEC_STATUS_TX_ERROR set\n");
>>>>> +                    cec->tx = STATE_ERROR;
>>>>> +            } else {
>>>>> +                    dev_dbg(cec->dev, "CEC_STATUS_TX_DONE\n");
>>>>> +                    cec->tx = STATE_DONE;
>>>>> +            }
>>>>> +            s5p_clr_pending_tx(cec);
>>>>> +    }
>>>>
>>>> Your CEC implementation seems to be written around the idea that there
>>>> are only two possible outcomes from a CEC message - "done" and "error",
>>>> which get translated to:
>>>
>>> This code is for the Samsung exynos CEC implementation. Marek, is this all
>>> that the exynos CEC hardware returns?
>>
>> The possible status values that are implemented in the CEC framework
>> are following:
>>
>> +/* cec status field */
>> +#define CEC_TX_STATUS_OK               (0)
>> +#define CEC_TX_STATUS_ARB_LOST         (1 << 0)
>> +#define CEC_TX_STATUS_RETRY_TIMEOUT    (1 << 1)
>> +#define CEC_TX_STATUS_FEATURE_ABORT    (1 << 2)
>> +#define CEC_TX_STATUS_REPLY_TIMEOUT    (1 << 3)
>> +#define CEC_RX_STATUS_READY            (0)
>>
>> The only two ones I could match with the Exynos CEC module status bits are
>> CEC_TX_STATUS_OK and  CEC_TX_STATUS_RETRY_TIMEOUT.
>>
>> The status bits in Exynos HW are:
>> - Tx_Error
>> - Tx_Done
>> - Tx_Transferring
>> - Tx_Running
>> - Tx_Bytes_Transferred
>>
>> - Tx_Wait
>> - Tx_Sending_Status_Bit
>> - Tx_Sending_Hdr_Blk
>> - Tx_Sending_Data_Blk
>> - Tx_Latest_Initiator
>>
>> - Tx_Wait_SFT_Succ
>> - Tx_Wait_SFT_New
>> - Tx_Wait_SFT_Retran
>> - Tx_Retrans_Cnt
>> - Tx_ACK_Failed
>
> So are these all intermediate states? And every transfer always ends with Tx_Done or
> Tx_Error state?

Yes, the Exynos CEC module has a pretty low level status indicator.

> It does look that way...
>
> Regards,
>
>         Hans
>

Best wishes,
Kamil

[snip]