Re: [RFC bluetooth-next 1/2] at86rf230: change trac status check behaviour

[Alexander Aring <alex.aring@gmail.com>]

On Thu, Aug 27, 2015 at 11:56:43AM +0200, Stefan Schmidt wrote:
> Hello.
> 
> On 06/08/15 17:21, Alexander Aring wrote:
> >When transmit is done, indicated by trx_end irq, we do first a force
> >state change to TX_ON and then checking the trac status, if the trac
> >status is unequal zero we do a state change to TRX_OFF.
> >
> >This patch changes to the following behaviour, we first check on trac
> >status after trx_end occurs and then doing a normal change to TX_ON
> >without do the state change to TRX_OFF when trac status is unequal zero.
> >
> >The reasons are that the datasheet doesn't described when the trac
> >status register is cleared, we should doing to evaluate the trac status
> >at first. The reason to remove the TRX_OFF change if the trac status is
> >unequal to zero and it was force is the following paragraph inside The
> >at86rf2xx datasheets:
> >
> >"Using FORCE_PLL_ON to interrupt an TX_ARET transaction, it is
> >  recommended to check register bits [7:5] of register address 0x32 for
> >  value 0. If this value is different, TRX_CMD sequence FORCE_TRX_OFF shall
> >  be used immediately followed by TRX_CMD sequence PLL_ON. This performs a
> >  state transition to PLL_ON."
> I had a hard time finding a register description of 0x32 in my copies. Are
> they outdated or am I just blind? Any hints appreciated. :)
> 

I think this is a mistake in the datasheet, they mean the "TRAC_STATUS"
here, which is the only value which fits in the range of [7:5] in
Register 0x02.

Nevertheless this handling is for interrupt the TX_ARET transaction,
then maybe this would be more fit if we do a that on the only once
FORCE_TX_ON change, this is at [0] when the maximum of "trying to change
into TX_ON is reached".

This case is very unlikely I would simple move always to FORCE_TRX_OFF
when interrupt any TX_*ON state. From TRX_OFF you can reach
RX_AACK_ON/TX_*ON states on all at86rf2xx(except 230 which we don't
support) transceivers

- Alex

[0] http://lxr.free-electrons.com/source/drivers/net/ieee802154/at86rf230.c#L558