Date:   Fri, 14 Feb 2020 10:33:25 +0100
From:   Michael Walle <michael@...le.cc>
To:     Joakim Zhang <qiangqing.zhang@....com>
Cc:     Marc Kleine-Budde <mkl@...gutronix.de>, wg@...ndegger.com,
        netdev@...r.kernel.org, linux-can@...r.kernel.org,
        Pankaj Bansal <pankaj.bansal@....com>,
        Shawn Guo <shawnguo@...nel.org>
Subject: Re: [PATCH 0/8] can: flexcan: add CAN FD support for NXP Flexcan

Am 2020-02-14 10:18, schrieb Joakim Zhang:
> Best Regards,
> Joakim Zhang
> 
>> -----Original Message-----
>> From: Michael Walle <michael@...le.cc>
>> Sent: 2020年2月14日 16:43
>> To: Joakim Zhang <qiangqing.zhang@....com>
>> Cc: Marc Kleine-Budde <mkl@...gutronix.de>; wg@...ndegger.com;
>> netdev@...r.kernel.org; linux-can@...r.kernel.org; Pankaj Bansal
>> <pankaj.bansal@....com>
>> Subject: Re: [PATCH 0/8] can: flexcan: add CAN FD support for NXP 
>> Flexcan
>> 
>> Hi Joakim,
>> 
>> Am 2020-02-14 02:55, schrieb Joakim Zhang:
>> > Hi Michal,
>> >
>> >> -----Original Message-----
>> >> From: Michael Walle <michael@...le.cc>
>> >> Sent: 2020年2月14日 3:20
>> >> To: Marc Kleine-Budde <mkl@...gutronix.de>
>> >> Cc: Joakim Zhang <qiangqing.zhang@....com>; wg@...ndegger.com;
>> >> netdev@...r.kernel.org; linux-can@...r.kernel.org; Pankaj Bansal
>> >> <pankaj.bansal@....com>; Michael Walle <michael@...le.cc>
>> >> Subject: Re: [PATCH 0/8] can: flexcan: add CAN FD support for NXP
>> >> Flexcan
>> >>
>> >> Hi,
>> >>
>> >> >>> Are you prepared to add back these patches as they are necessary
>> >> >>> for Flexcan CAN FD? And this Flexcan CAN FD patch set is based on
>> >> >>> these patches.
>> >> >>
>> >> >> Yes, these patches will be added back.
>> >> >
>> >> >I've cleaned up the first patch a bit, and pushed everything to the
>> >> >testing branch. Can you give it a test.
>> >>
>> >> What happend to that branch? FWIW I've just tried the patches on a
>> >> custom board with a LS1028A SoC. Both CAN and CAN-FD are working.
>> >> I've tested against a Peaktech USB CAN adapter. I'd love to see these
>> >> patches upstream, because our board also offers CAN and basic support
>> >> for it just made it upstream [1].
>> > The FlexCAN CAN FD related patches have stayed in
>> > linux-can-next/flexcan branch for a long time, I still don't know why
>> > Marc doesn't merge them into Linux mainline.
>> > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.
>> >
>> kernel.org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Fmkl%2Flinux-can-next.g
>> >
>> it%2Ftree%2F%3Fh%3Dflexcan&amp;data=02%7C01%7Cqiangqing.zhang%40n
>> xp.co
>> >
>> m%7C94dca4472a584410b3b908d7b129db27%7C686ea1d3bc2b4c6fa92cd99c
>> 5c30163
>> >
>> 5%7C0%7C0%7C637172665642079192&amp;sdata=77tG6VuQCi%2FZXBKb23
>> 8%2FdNSV3
>> > NUIFrM5Y0e9yj0J3os%3D&amp;reserved=0
>> > Also must hope that this patch set can be upstreamed soon. :-)
>> 
>> I've took them from this branch and applied them to the latest linux 
>> master.
>> 
>> Thus,
>> 
>> Tested-by: Michael Walle <michael@...le.cc>
>> 
>> 
>> >> If these patches are upstream, only the device tree nodes seems to be
>> >> missing.
>> >> I don't know what has happened to [2]. But the patch doesn't seem to
>> >> be necessary.
>> > Yes, this patch is unnecessary. I have NACKed this patch for that,
>> > according to FlexCAN Integrated Guide, CTRL1[CLKSRC]=0 select
>> > oscillator clock and CTRL1[CLKSRC]=1 select peripheral clock.
>> > But it is actually decided by SoC integration, for i.MX, the design is
>> > different.
>> 
>> ok thanks for clarifying.
>> 
>> > I have not upstream i.MX FlexCAN device tree nodes, since it's
>> > dependency have not upstreamed yet.
>> >
>> >> Pankaj already send a patch to add the device node to the LS1028A [3].
>> >> Thats basically the same I've used, only that mine didn't had the
>> >> "fsl,ls1028ar1-flexcan" compatiblity string, but only the
>> >> "lx2160ar1-flexcan"
>> >> which is the correct way to use it, right?
>> > You can see below table from FlexCAN driver, "fsl,lx2160ar1-flexcan"
>> > supports CAN FD, you can use this compatible string.
>> 
>> correct. I've already a patch that does exactly this ;) Who would take 
>> the patch
>> for adding the LS1028A can device tree nodes to ls1028a.dtsi? You or 
>> Shawn
>> Guo?
> Sorry, I missed the link[3], we usually write it this way:
> 			compatible = "fsl,ls1028ar1-flexcan","fsl,lx2160ar1-flexcan";
> Please send patch to Shawn Guo, he will review the device tree.

As far as I know, there should be no undocumented binding. Eg. the 
ls1028ar1-flexcan
is neither in the source nor in the device tree binding documentation, 
thus wouldn't
be accepted.

Thus either there should be another ls1028ar1-flexcan in the 
flexcan_of_match table
and the node should only contain that string or the node should only 
contain
fsl,lx2160ar1-flexcan. Is there any advantage of the first option?


-michael


> 
>> > static const struct of_device_id flexcan_of_match[] = {
>> > 	{ .compatible = "fsl,imx8qm-flexcan", .data =
>> > &fsl_imx8qm_devtype_data, },
>> > 	{ .compatible = "fsl,imx6q-flexcan", .data = &fsl_imx6q_devtype_data,
>> > },
>> > 	{ .compatible = "fsl,imx28-flexcan", .data = &fsl_imx28_devtype_data,
>> > },
>> > 	{ .compatible = "fsl,imx53-flexcan", .data = &fsl_imx25_devtype_data,
>> > },
>> > 	{ .compatible = "fsl,imx35-flexcan", .data = &fsl_imx25_devtype_data,
>> > },
>> > 	{ .compatible = "fsl,imx25-flexcan", .data = &fsl_imx25_devtype_data,
>> > },
>> > 	{ .compatible = "fsl,p1010-flexcan", .data = &fsl_p1010_devtype_data,
>> > },
>> > 	{ .compatible = "fsl,vf610-flexcan", .data = &fsl_vf610_devtype_data,
>> > },
>> > 	{ .compatible = "fsl,ls1021ar2-flexcan", .data =
>> > &fsl_ls1021a_r2_devtype_data, },
>> > 	{ .compatible = "fsl,lx2160ar1-flexcan", .data =
>> > &fsl_lx2160a_r1_devtype_data, },
>> > 	{ /* sentinel */ },
>> > };
>> >
>> 
>> -michael

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