RE: About bittiming calculation result

From: Bhupesh SHARMA
Date: Mon Feb 07 2011 - 22:30:49 EST


Hi Tomoya,

> -----Original Message-----
> From: socketcan-core-bounces@xxxxxxxxxxxxxxxx [mailto:socketcan-core-
> bounces@xxxxxxxxxxxxxxxx] On Behalf Of Tomoya MORINAGA
> Sent: Tuesday, February 08, 2011 6:40 AM
> To: 'Wolfgang Grandegger'
> Cc: socketcan-core@xxxxxxxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx
> Subject: RE: About bittiming calculation result
>
> On Monday, February 07, 2011 9:01 PM, Wolfgang Grandegger wrote
> >
> > Well, only prop_seg+phase_seg=tseg1 is relevant and the
> > pch_can driver sets the allowed minimum "tseg1_min1" currently to 1:
> >
> > static struct can_bittiming_const pch_can_bittiming_const = {
> > .name = KBUILD_MODNAME,
> > .tseg1_min = 1,
> > .tseg1_max = 16,
> > .tseg2_min = 1,
> > .tseg2_max = 8,
> > .sjw_max = 4,
> > .brp_min = 1,
> > .brp_max = 1024, /* 6bit + extended 4bit */
> > .brp_inc = 1,
> > };
> >
> > > seg1/seg2/sjw/prop_seg must be more than 1 ?
> >
> > Then "tseg1_min" should be set to *2*.
>
> Though some drivers accepted by upstream have parameter "tseg1_min" as
> 1,
> Sould we release the patch like below ?
> - .tseg1_min = 1,
> + .tseg1_min = 2,
>
AFAIK pch uses the Bosch C_CAN core internally.
As per Bosch C_CAN user manual tseg1= prop_seg + phase_seg1
So, ideally tseg1_min should be 2. My version of Bosch C_CAN driver
Uses the value 2.

Regards,
Bhupesh
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