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Date: Mon, 8 Aug 2011 11:08:10 -0500 From: Robin Holt <holt@....com> To: Wolfgang Grandegger <wg@...ndegger.com> Cc: Robin Holt <holt@....com>, Marc Kleine-Budde <mkl@...gutronix.de>, socketcan-core@...ts.berlios.de, netdev@...r.kernel.org, U Bhaskar-B22300 <B22300@...escale.com> Subject: Re: [RFC 5/5] [powerpc] Implement a p1010rdb clock source. On Mon, Aug 08, 2011 at 06:03:06PM +0200, Wolfgang Grandegger wrote: > On 08/08/2011 05:55 PM, Robin Holt wrote: > > On Mon, Aug 08, 2011 at 05:33:53PM +0200, Wolfgang Grandegger wrote: > >> On 08/08/2011 05:14 PM, Marc Kleine-Budde wrote: > > ... > > > >>> On 08/08/2011 04:59 PM, Wolfgang Grandegger wrote: > >>>> On 08/08/2011 04:44 PM, Robin Holt wrote: > >>>>> On Mon, Aug 08, 2011 at 04:37:44PM +0200, Wolfgang Grandegger wrote: > >>>>>> On 08/08/2011 04:21 PM, Robin Holt wrote: > >>>>>>> On Mon, Aug 08, 2011 at 04:16:27PM +0200, Wolfgang Grandegger wrote: > >>>>>>>> On 08/08/2011 03:56 PM, Robin Holt wrote: > >>>>>>>>>> commit 65bb8b060a873fa4f5188f2951081f6011259614 > >>>>>>>>>> Author: Bhaskar Upadhaya <Bhaskar.Upadhaya@...escale.com> > >>>>>>>>>> Date: Fri Mar 4 20:27:58 2011 +0530 > >>>>>>>>> > >>>>>>>>> On a side note, that commit fixes up "fsl,flexcan-v1.0" > >>>>>>>>> ... > >>>>>>>>> + do_fixup_by_compat_u32(blob, "fsl,flexcan-v1.0", > >>>>>>>>> + "clock_freq", gd->bus_clk, 1); > >>>>>>>>> > >>>>>>>>> Should I go back to flexcan-v1.0 in my patches? > >>>>>>>> > >>>>>>>> Well, no. Let's wait. I don't think we need it. Also, it sets > >>>>>>>> "clock_freq" while > >>>>>>>> > >>>>>>>> http://lxr.linux.no/#linux+v3.0.1/Documentation/devicetree/bindings/net/can/fsl-flexcan.txt > >>>>>>>> > >>>>>>>> documents "clock-frequencies"... :-(. > >>>>>>> > >>>>>>> You answered a different question that I was asking. I was asking if > >>>>>>> I should change fsl,flexcan back to fsl,flexcan-v1.0 as documented on > >>>>>>> line 5. The clock_freq looks like a uboot change will need to be made > >>>>>>> as well. > >>>>>> > >>>>>> Well, I wrote above: "Well, no. Let's wait. I don't think we need it." > >>>>>> > >>>>>> For the P1010 we can sinmply derive the clock frequency from > >>>>>> "fsl_get_sys_freq()", which is fine for the time being. No extra > >>>>>> properties, etc. The clk implemetation might go into > >>>>>> > >>>>>> http://lxr.linux.no/#linux+v3.0.1/arch/powerpc/platforms/85xx/clock.c > >>>>>> > >>>>>> or > >>>>>> > >>>>>> http://lxr.linux.no/#linux+v3.0.1/arch/powerpc/sysdev/fsl_soc.c > >>>>>> > >>>>>> And may depend on HAVE_CAN_FLEXCAN > >>>>>> > >>>>>> BTW, I have not found HAVE_CAN_FLEXCAN in your patch. What kernel are > >>>>>> you using? > >>>>> > >>>>> I am starting with the v3.0 kernel, apply one patch from the freescale BSP > >>>>> we receive under NDA which introduces the P1010RDB board into the QorIQ > >>>>> platform, and then work from there for the flexcan stuff. That patch > >>>>> introduces the HAVE_CAN_FLEXCAN. I do not like how freescale structured > >>>>> that Kconfig bit, so I have tweaked it to be selected automatically > >>>>> when P1010RDB, NET, and CAN are selected. That allows the CAN_FLEXCAN > >>>>> selection to determine is we are going to build the flexcan.c file. > >>>> > >>>> ARM boards select HAVE_CAN_FLEXCAN and I do not see a good reason why > >>>> we should do it differently for PowerPC. > >>>> > >>>> For mainline inclusion, you should provide your patches against the > >>>> David Millers "net-next-2.6" tree, which already seems to have support > >>>> for the P1010RDB: > >>>> > >>>> config P1010_RDB > >>>> bool "Freescale P1010RDB" > >>>> select DEFAULT_UIMAGE > >>>> help > >>>> This option enables support for the MPC85xx RDB (P1010 RDB) board > >>>> > >>>> P1010RDB contains P1010Si, which provides CPU performance up to 800 > >>>> MHz and 1600 DMIPS, additional functionality and faster interfaces > >>>> (DDR3/3L, SATA II, and PCI Express). > >>>> > >>>> > >>>>> Our contact with Freescale would prefer that I not post that patch until > >>>>> we get the OK from freescale to do so since we received it under NDA. > >>>> > >>>> I don't think we currently need it. I prefer dropping and cleaning up > >>>> the device tree stuff as it is not needed for the P1010 anyway. If a > >>>> new processor shows up with enhanced capabilities requiring > >>>> configuration via device tree, we or somebody else can provide a patch. > >>>> Marc, what do you think? > >>> > >>> ACK - The device tree bindings as in mainline's Documentation is a mess. > >>> If the powerpc guys are happy with a clock interfaces based approach > >>> somewhere in arch/ppc, I'm more than happy to remove: > >>> - fsl,flexcan-clock-source (not implemented, even in the fsl driver) > >>> > >>> - fsl,flexcan-clock-divider \__ replace with code in arch/ppc, or > >>> - clock-frequency / a single clock-frequency attribute > >> > >> In the "net-next-2.6" tree there is also: > >> > >> $ grep flexcan arch/powerpc/boots/dts/*.dts > >> p1010rdb.dts: fsl,flexcan-clock-source = "platform"; > >> p1010rdb.dts: fsl,flexcan-clock-source = "platform"; > >> p1010si.dtsi: compatible = "fsl,flexcan-v1.0"; > >> p1010si.dtsi: fsl,flexcan-clock-divider = <2>; > >> p1010si.dtsi: compatible = "fsl,flexcan-v1.0"; > >> p1010si.dtsi: fsl,flexcan-clock-divider = <2>; > >> > >> Especially the fsl,flexcan-clock-divider = <2>; might make people think, > >> that they could set something else. > > > > I am currently lost on the direction. I think I need something like: > > > > 1) Patch 1/5 removing the "#include <mach/clock.h>" stays. > > OK. Is that an Acked-by: or not? > > > 2) Patch 2/5 abstracting readl/writel stays. > > OK. Is that an Acked-by: or not? > > > 3) Patch 3/5 of_match for ppc and the match string is "fsl,flexcan" stays. > > Yep. Done. > > > 4) Patch 4/5 I have not been given clear direction to not do it but have > > not gotten a favorable response. > > Please drop this one for mainline. Done. > > > 5) Patch 5/5 goes from being a powerpc patch back to being a flexcan.c > > No, I just would prefer a more general place, e.g.: > > http://lxr.linux.no/#linux+v3.0.1/arch/powerpc/platforms/85xx/clock.c > > Furthermore you need patches to cleanup some DTS and platform files and > the Documentation. So we would stay with the clk_* functions. I assume clk_get() would return NULL, clk_get_rate() would just return fsl_get_sys_freq() and the other functions would do nothing. Doesn't this really polute what clk_* functions are supposed to do? Aren't we making flexcan dictate a different behavior for powerpc than for the arm (and possibly other) architectures? Thanks, Robin -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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