Re: [PATCH net-next-2.6 12/17 v3] can: EG20T PCH: Fix bit timing calculation issue - Marc Kleine-Budde

From: Marc Kleine-Budde <mkl-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
To: Tomoya MORINAGA <tomoya-linux-ECg8zkTtlr0C6LszWs/t0g@public.gmane.org>
Cc: andrew.chih.howe.khor-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org,
	Samuel Ortiz <sameo-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>,
	margie.foster-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org,
	netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	socketcan-core-0fE9KPoRgkgATYTw5x5z8w@public.gmane.org,
	yong.y.wang-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org,
	kok.howg.ewe-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org,
	Wolfgang Grandegger <wg-5Yr1BZd7O62+XT7JhA+gdA@public.gmane.org>,
	joel.clark-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org,
	"David S. Miller" <davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>,
	Christian Pellegrin <chripell-VaTbYqLCNhc@public.gmane.org>,
	qi.wang-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org
Subject: Re: [PATCH net-next-2.6 12/17 v3] can: EG20T PCH: Fix bit timing calculation issue
Date: Wed, 24 Nov 2010 13:58:25 +0100	[thread overview]
Message-ID: <4CED0BF1.1060305@pengutronix.de> (raw)
In-Reply-To: <4CED037F.6060306-ECg8zkTtlr0C6LszWs/t0g@public.gmane.org>

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On 11/24/2010 01:22 PM, Tomoya MORINAGA wrote:
> Fix bit timing calculation issue
> Modify like use calculated value directly passed by CAN core module.
> 
> Signed-off-by: Tomoya MORINAGA <tomoya-linux-ECg8zkTtlr0C6LszWs/t0g@public.gmane.org>

Acked-by: Marc Kleine-Budde <mkl-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>

> ---
>  drivers/net/can/pch_can.c |    6 ++----
>  1 files changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/net/can/pch_can.c b/drivers/net/can/pch_can.c
> index 7342030..466f011 100644
> --- a/drivers/net/can/pch_can.c
> +++ b/drivers/net/can/pch_can.c
> @@ -800,17 +800,15 @@ static int pch_set_bittiming(struct net_device *ndev)
>  	const struct can_bittiming *bt = &priv->can.bittiming;
>  	u32 canbit;
>  	u32 bepe;
> -	u32 brp;
> 
>  	/* Setting the CCE bit for accessing the Can Timing register. */
>  	pch_can_bit_set(&priv->regs->cont, PCH_CTRL_CCE);
> 
> -	brp = (bt->tq) / (1000000000/PCH_CAN_CLK) - 1;
> -	canbit = brp & PCH_MSK_BITT_BRP;
> +	canbit = (bt->brp - 1) & PCH_MSK_BITT_BRP;

Masking here shouldn't be necessary but won't hurt, better play safe.

>  	canbit |= (bt->sjw - 1) << PCH_BIT_SJW_SHIFT;
>  	canbit |= (bt->phase_seg1 + bt->prop_seg - 1) << PCH_BIT_TSEG1_SHIFT;
>  	canbit |= (bt->phase_seg2 - 1) << PCH_BIT_TSEG2_SHIFT;
> -	bepe = (brp & PCH_MSK_BRPE_BRPE) >> PCH_BIT_BRPE_BRPE_SHIFT;
> +	bepe = ((bt->brp - 1) & PCH_MSK_BRPE_BRPE) >> PCH_BIT_BRPE_BRPE_SHIFT;

dito

>  	iowrite32(canbit, &priv->regs->bitt);
>  	iowrite32(bepe, &priv->regs->brpe);
>  	pch_can_bit_clear(&priv->regs->cont, PCH_CTRL_CCE);

cheers, Marc

-- 
Pengutronix e.K.                  | Marc Kleine-Budde           |
Industrial Linux Solutions        | Phone: +49-231-2826-924     |
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