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From: Wolfgang Grandegger <wg-5Yr1BZd7O62+XT7JhA+gdA@public•gmane.org>
To: Masayuki Ohtake <masa-korg-ECg8zkTtlr0C6LszWs/t0g@public•gmane.org>
Cc: Andrew Chih Howe
	<andrew.chih.howe.khor-ral2JQCrhuEAvxtiuMwx3w@public•gmane.org>,
	Samuel Ortiz <sameo-VuQAYsv1563Yd54FQh9/CA@public•gmane.org>,
	ML netdev <netdev-u79uwXL29TY76Z2rM5mHXA@public•gmane.org>,
	gregkh-l3A5Bk7waGM@public•gmane.org,
	ML linux-kernel
	<linux-kernel-u79uwXL29TY76Z2rM5mHXA@public•gmane.org>,
	"Wang,
	Yong Y" <yong.y.wang-ral2JQCrhuEAvxtiuMwx3w@public•gmane.org>,
	socketcan-core-0fE9KPoRgkgATYTw5x5z8w@public•gmane.org,
	Morinaga <morinaga526-ECg8zkTtlr0C6LszWs/t0g@public•gmane.org>,
	arjan-VuQAYsv1563Yd54FQh9/CA@public•gmane.org,
	"David S. Miller" <davem-fT/PcQaiUtIeIZ0/mPfg9Q@public•gmane.org>,
	Christian Pellegrin <chripell-VaTbYqLCNhc@public•gmane.org>,
	Qi <qi.wang-ral2JQCrhuEAvxtiuMwx3w@public•gmane.org>
Subject: Re: [MeeGo-Dev][PATCH] Topcliff: Update PCH_CAN driver to 2.6.35
Date: Thu, 02 Sep 2010 08:32:44 +0200	[thread overview]
Message-ID: <4C7F450C.4010002@grandegger.com> (raw)
In-Reply-To: <001301cb4a4d$b4c4ba80$66f8800a-a06+6cuVnkTSQfdrb5gaxUEOCMrvLtNR@public.gmane.org>

On 09/02/2010 05:19 AM, Masayuki Ohtake wrote:
> ----- Original Message ----- 
> From: "Wolfgang Grandegger" <wg-5Yr1BZd7O62+XT7JhA+gdA@public•gmane.org>
> To: "Masayuki Ohtake" <masa-korg-ECg8zkTtlr0C6LszWs/t0g@public•gmane.org>
> Cc: "Andrew Chih Howe" <andrew.chih.howe.khor-ral2JQCrhuEAvxtiuMwx3w@public•gmane.org>; "Qi" <qi.wang-ral2JQCrhuEAvxtiuMwx3w@public•gmane.org>; "ML netdev"
> <netdev-u79uwXL29TY76Z2rM5mHXA@public•gmane.org>; <gregkh-l3A5Bk7waGM@public•gmane.org>; "ML linux-kernel" <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public•gmane.org>; "Wang, Yong Y"
> <yong.y.wang-ral2JQCrhuEAvxtiuMwx3w@public•gmane.org>; <socketcan-core-0fE9KPoRgkgATYTw5x5z8w@public•gmane.org>; <arjan-VuQAYsv1563Yd54FQh9/CA@public•gmane.org>; "David S. Miller"
> <davem-fT/PcQaiUtIeIZ0/mPfg9Q@public•gmane.org>; "Christian Pellegrin" <chripell-VaTbYqLCNhc@public•gmane.org>; "Samuel Ortiz" <sameo-VuQAYsv1563Yd54FQh9/CA@public•gmane.org>
> Sent: Thursday, September 02, 2010 3:51 AM
> Subject: Re: [MeeGo-Dev][PATCH] Topcliff: Update PCH_CAN driver to 2.6.35
> 
>> ...
>>>>>>> - The values for the hw-specific bit-timing registers should be derived
>>>>>>>   from the calculated values in "priv->can.bittiming":
>>>>>>>
>>>>>>>   http://lxr.linux.no/#linux+v2.6.35/include/linux/can/netlink.h#L17
>>>>>>>
>>>
>>> I show current pch_can code below.
>>>
>>> +static int pch_set_bittiming(struct net_device *ndev)
>>> +{
>>> + struct pch_can_priv *priv = netdev_priv(ndev);
>>> + struct pch_can_os *dev_can_os = priv->pch_can_os_p;
>>> + const struct can_bittiming *bt = &priv->can.bittiming;
>>>
>>> Is the above TRUE, isn't it ?
>>
>> The code fragment looks good. In that function you should then *derive*
>> the values of the bit-timing registers from the data fields of "bt". For
>> the SJA1000, you find the code here:
>>
>> http://lxr.linux.no/#linux+v2.6.35/drivers/net/can/sja1000/sja1000.c#L202
>>
> 
> I can't understand the your saying.
> I think our can driver is implemented like your saying.
> 
> In function "pch_set_bittiming", get the value of the bit-timing registers from
> the data fields of "bt" at "pch_can_set_baud_custom" or "pch_can_set_baud_simple".

Please *remove* "pch_can_set_baud_custom" or "pch_can_set_baud_simple"
and use the fields of "const struct can_bittiming *bt" *directly*:

  /* Getting the appropriate register value. */
  reg_val = (((bt->brp & MSK_BITT_BRP) << BIT_BITT_BRP) |
	    ((bt->prop_seg + bt->phase_seg1 - 1) << BIT_BITT_TSEG1) |
            ...

> Could you indicate in more detail ?

Please have a closer look to the link mentioned above.

>>>>>>> - The driver should handle state changes and communicate them to the
>>>>>>>   user space via error messages, if possible.
>>>>>>>
>>> What's "state chage" mean ?
>>
>> Googling for "can bis states" returned:
>>
>>
> http://www.softing.com/home/en/industrial-automation/products/can-bus/more-can-bus/error-handling/error-states.php?navanchor=3010510
>>
>> The CAN controller usually triggers an interrupt when the state changes,
>> which allows the driver to track the CAN state and deliver that
>> information to the user space.
> 
> I could understand your saying.
> In our current code, our driver can detect state change, but doesn't notify to
> can-core module or kennel protocol stack.
> We will modify our driver to notify to these.

The code is your friend. Please have a more detailed look to the SJA1000
driver, e.g. search it for "state".

Wolfgang.

  parent reply	other threads:[~2010-09-02  6:32 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-08-11  0:25 [MeeGo-Dev][PATCH] Topcliff: Update PCH_CAN driver to 2.6.35 Masayuki Ohtak
     [not found] ` <4C61EDE5.4030505-ECg8zkTtlr0C6LszWs/t0g@public.gmane.org>
2010-08-11 10:37   ` Daniel Baluta
2010-08-12  1:42     ` Wang, Qi
2010-08-12  2:04       ` Greg KH
2010-08-12  2:13         ` Wang, Qi
     [not found]         ` <20100812020414.GD14121-l3A5Bk7waGM@public.gmane.org>
2010-08-12  6:25           ` Oliver Hartkopp
2010-08-12  6:29             ` Wang, Qi
2010-08-12  2:39       ` Masayuki Ohtake
     [not found]       ` <D5AB6E638E5A3E4B8F4406B113A5A19A28EA26EB-QQHDSDV1ERZpB2pF5aRoyrfspsVTdybXVpNB7YpNyf8@public.gmane.org>
2010-08-12  5:17         ` Daniel Baluta
2010-08-12  9:03         ` Wolfgang Grandegger
2010-08-13  0:23           ` Wang, Qi
     [not found]             ` <D5AB6E638E5A3E4B8F4406B113A5A19A28EA2AB1-QQHDSDV1ERZpB2pF5aRoyrfspsVTdybXVpNB7YpNyf8@public.gmane.org>
2010-08-13  6:11               ` Daniel Baluta
2010-08-13 10:58               ` Wolfgang Grandegger
2010-08-20  6:01                 ` Masayuki Ohtake
     [not found]                   ` <000f01cb402d$34b675b0$66f8800a-a06+6cuVnkTSQfdrb5gaxUEOCMrvLtNR@public.gmane.org>
2010-08-20  7:59                     ` Wolfgang Grandegger
2010-08-20  8:37                       ` Masayuki Ohtake
2010-08-11 12:31   ` Wolfgang Grandegger
     [not found]     ` <D5AB6E638E5A3E4B8F4406B113A5A19A28EA26CC@shsmsx501.ccr.corp.intel.com>
     [not found]       ` <4C63B6C9.5050804@grandegger.com>
     [not found]         ` <D5AB6E638E5A3E4B8F4406B113A5A19A28EA29DF@shsmsx501.ccr.corp.intel.com>
2010-09-01  7:45           ` Masayuki Ohtake
     [not found]             ` <000501cb49a9$9cd4bf00$66f8800a-a06+6cuVnkTSQfdrb5gaxUEOCMrvLtNR@public.gmane.org>
2010-09-01 17:04               ` out-of-order tx objects - was " Oliver Hartkopp
2010-09-01 18:51               ` Wolfgang Grandegger
2010-09-02  3:19                 ` Masayuki Ohtake
     [not found]                   ` <001301cb4a4d$b4c4ba80$66f8800a-a06+6cuVnkTSQfdrb5gaxUEOCMrvLtNR@public.gmane.org>
2010-09-02  6:32                     ` Wolfgang Grandegger [this message]
2010-08-11 13:04   ` Marc Kleine-Budde
2010-09-13 12:07     ` Masayuki Ohtake
     [not found]       ` <005f01cb533e$5c21d530$66f8800a-a06+6cuVnkTSQfdrb5gaxUEOCMrvLtNR@public.gmane.org>
2010-09-13 12:29         ` Marc Kleine-Budde
2010-09-14  0:46           ` Masayuki Ohtake
2010-09-14  7:08             ` Marc Kleine-Budde
     [not found]             ` <003a01cb53a6$4ca724d0$66f8800a-a06+6cuVnkTSQfdrb5gaxUEOCMrvLtNR@public.gmane.org>
2010-09-15  7:42               ` Wolfgang Grandegger
     [not found]                 ` <4C9078D3.50300-5Yr1BZd7O62+XT7JhA+gdA@public.gmane.org>
2010-09-15  9:42                   ` Oliver Hartkopp
2010-09-15 10:55                     ` Wolfgang Grandegger
2010-09-15 12:04                       ` Marc Kleine-Budde
2010-09-15 12:11                         ` Wolfgang Grandegger
2010-09-13 15:22         ` Greg KH
2010-09-14  8:48           ` Masayuki Ohtake
     [not found]             ` <00ca01cb53e9$a50c1930$66f8800a-a06+6cuVnkTSQfdrb5gaxUEOCMrvLtNR@public.gmane.org>
2010-09-14 13:10               ` Greg KH
2010-09-15  1:21                 ` Masayuki Ohtake

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