On Aug 10, 2011, at 11:00 AM, Robin Holt wrote: > On Wed, Aug 10, 2011 at 02:36:20PM +0000, U Bhaskar-B22300 wrote: >> >> >>> -----Original Message----- >>> From: Robin Holt [mailto:h...@sgi.com] >>> Sent: Wednesday, August 10, 2011 7:46 PM >>> To: Wolfgang Grandegger >>> Cc: Robin Holt; Marc Kleine-Budde; U Bhaskar-B22300; Wood Scott-B07421; >>> net...@vger.kernel.org; Kumar Gala; socketcan-c...@lists.berlios.de; PPC >>> list >>> Subject: Re: [PATCH v10 5/5] [powerpc] Fix up fsl-flexcan device tree >>> binding. >>> >>> On Wed, Aug 10, 2011 at 03:47:43PM +0200, Wolfgang Grandegger wrote: >>>> Hi Robin, >>>> >>>> On 08/10/2011 05:06 AM, Robin Holt wrote: >>>>> In working with the socketcan developers, we have come to the >>>>> conclusion the Documentation...fsl-flexcan.txt device tree >>>>> documentation needs to be cleaned up. The driver does not depend >>>>> upon any properties other >>>> >>>> Your first sentence could be misleading. Please just describe what the >>>> patch does and why, something like: >>>> >>>> "This patch cleans up the documentation of the device-tree binding for >>>> the Flexcan devices on Freescale's PowerPC and ARM cores. Extra >>>> properties are not needed as the frequency of the source clock is >>>> fixed..." and so on. >>> >>> I borrowed heavily from your message. ;) >>> >>>>> than the required properties so we are removing the file. >>>>> Additionally, the p1010*dts* files are not following the standard >>>>> for node naming in that they have a trailing -v1.0. >>>> >>>>> Signed-off-by: Robin Holt <h...@sgi.com> >>>>> To: Marc Kleine-Budde <m...@pengutronix.de>, >>>>> To: Wolfgang Grandegger <w...@grandegger.com>, >>>>> To: U Bhaskar-B22300 <b22...@freescale.com> >>>>> To: Scott Wood <scottw...@freescale.com> >>>>> Cc: socketcan-c...@lists.berlios.de, >>>>> Cc: net...@vger.kernel.org, >>>>> Cc: PPC list <linuxppc-dev@lists.ozlabs.org> >>>>> Cc: Kumar Gala <ga...@kernel.crashing.org> >>>>> --- >>>>> .../devicetree/bindings/net/can/fsl-flexcan.txt | 61 ---------- >>> ---------- >>>>> arch/powerpc/boot/dts/p1010rdb.dts | 8 --- >>>>> arch/powerpc/boot/dts/p1010si.dtsi | 8 +- >>>>> 3 files changed, 4 insertions(+), 73 deletions(-) delete mode >>>>> 100644 Documentation/devicetree/bindings/net/can/fsl-flexcan.txt >>>>> >>>>> diff --git >>>>> a/Documentation/devicetree/bindings/net/can/fsl-flexcan.txt >>>>> b/Documentation/devicetree/bindings/net/can/fsl-flexcan.txt >>>>> deleted file mode 100644 >>>>> index 1a729f0..0000000 >>>>> --- a/Documentation/devicetree/bindings/net/can/fsl-flexcan.txt >>>>> +++ /dev/null >>>>> @@ -1,61 +0,0 @@ >>>>> -CAN Device Tree Bindings >>>>> ------------------------- >>>>> -2011 Freescale Semiconductor, Inc. >>>>> - >>>>> -fsl,flexcan-v1.0 nodes >>>>> ------------------------ >>>>> -In addition to the required compatible-, reg- and >>>>> interrupt-properties, you can -also specify which clock source shall >>> be used for the controller. >>>>> - >>>>> -CPI Clock- Can Protocol Interface Clock >>>>> - This CLK_SRC bit of CTRL(control register) selects the clock source >>> to >>>>> - the CAN Protocol Interface(CPI) to be either the peripheral clock >>>>> - (driven by the PLL) or the crystal oscillator clock. The selected >>> clock >>>>> - is the one fed to the prescaler to generate the Serial Clock >>> (Sclock). >>>>> - The PRESDIV field of CTRL(control register) controls a prescaler >>> that >>>>> - generates the Serial Clock (Sclock), whose period defines the >>>>> - time quantum used to compose the CAN waveform. >>>>> - >>>>> -Can Engine Clock Source >>>>> - There are two sources for CAN clock >>>>> - - Platform Clock It represents the bus clock >>>>> - - Oscillator Clock >>>>> - >>>>> - Peripheral Clock (PLL) >>>>> - -------------- >>>>> - | >>>>> - --------- ------------- >>>>> - | |CPI Clock | Prescaler | Sclock >>>>> - | |---------------->| (1.. 256) |------------> >>>>> - --------- ------------- >>>>> - | | >>>>> - -------------- ---------------------CLK_SRC >>>>> - Oscillator Clock >>>>> - >>>>> -- fsl,flexcan-clock-source : CAN Engine Clock Source.This property >>> selects >>>>> - the peripheral clock. PLL clock is fed to the >>>>> - prescaler to generate the Serial Clock (Sclock). >>>>> - Valid values are "oscillator" and "platform" >>>>> - "oscillator": CAN engine clock source is >>> oscillator clock. >>>>> - "platform" The CAN engine clock source is the bus >>> clock >>>>> - (platform clock). >>>>> - >>>>> -- fsl,flexcan-clock-divider : for the reference and system clock, an >>> additional >>>>> - clock divider can be specified. >>>>> -- clock-frequency: frequency required to calculate the bitrate for >>> FlexCAN. >>>>> - >>>>> -Note: >>>>> - - v1.0 of flexcan-v1.0 represent the IP block version for P1010 >>> SOC. >>>>> - - P1010 does not have oscillator as the Clock Source.So the default >>>>> - Clock Source is platform clock. >>>>> -Examples: >>>>> - >>>>> - can0@1c000 { >>>>> - compatible = "fsl,flexcan-v1.0"; >>>>> - reg = <0x1c000 0x1000>; >>>>> - interrupts = <48 0x2>; >>>>> - interrupt-parent = <&mpic>; >>>>> - fsl,flexcan-clock-source = "platform"; >>>>> - fsl,flexcan-clock-divqider = <2>; >>>>> - clock-frequency = <fixed by u-boot>; >>>>> - }; >>>> >>>> Do we really want to drop the documentation for that binding. I think >>>> something like the following text would be still useful: >>>> >>>> ------------------------ >>>> Flexcan CAN contoller on Freescale's ARM and PowerPC processors >>>> >>>> Required properties: >>>> >>>> - compatible : Should be "fsl,flexcan" and optionally >>>> "fsl,flexcan-<processor>" >>>> - reg : Offset and length of the register set for this device >>>> - interrupts : Interrupt tuple for this device >>>> >>>> Example: >>>> >>>> can@1c000 { >>>> compatible = "fsl,p1010-flexcan", "fsl,flexcan"; >>>> reg = <0x1c000 0x1000>; >>>> interrupts = <48 0x2>; >>>> interrupt-parent = <&mpic>; >>>> }; >>>> ------------------------- >>> >>> Done, except the >>>> compatible = "fsl,p1010-flexcan", "fsl,flexcan"; >>> >>> line is >>> compatible = "fsl,flexcan", "fsl,flexcan-p1010"; >>> >>>> >>>> What do you think? >>>> >>>>> diff --git a/arch/powerpc/boot/dts/p1010rdb.dts >>>>> b/arch/powerpc/boot/dts/p1010rdb.dts >>>>> index 6b33b73..d6a0bb2 100644 >>>>> --- a/arch/powerpc/boot/dts/p1010rdb.dts >>>>> +++ b/arch/powerpc/boot/dts/p1010rdb.dts >>>>> @@ -169,14 +169,6 @@ >>>>> }; >>>>> }; >>>>> >>>>> - can0@1c000 { >>>>> - fsl,flexcan-clock-source = "platform"; >>>>> - }; >>>>> - >>>>> - can1@1d000 { >>>>> - fsl,flexcan-clock-source = "platform"; >>>>> - }; >>>>> - >>>>> usb@22000 { >>>>> phy_type = "utmi"; >>>>> }; >>>>> diff --git a/arch/powerpc/boot/dts/p1010si.dtsi >>>>> b/arch/powerpc/boot/dts/p1010si.dtsi >>>>> index 7f51104..20c396d 100644 >>>>> --- a/arch/powerpc/boot/dts/p1010si.dtsi >>>>> +++ b/arch/powerpc/boot/dts/p1010si.dtsi >>>>> @@ -141,19 +141,19 @@ >>>>> }; >>>>> >>>>> can0@1c000 { >>>>> - compatible = "fsl,flexcan-v1.0"; >>>>> + compatible = "fsl,p1010-flexcan", >>>>> + "fsl,flexcan"; >>>> >>>> Does fit on one line. >>>> >>>>> reg = <0x1c000 0x1000>; >>>>> interrupts = <48 0x2>; >>>>> interrupt-parent = <&mpic>; >>>>> - fsl,flexcan-clock-divider = <2>; >>>>> }; >>>>> >>>>> can1@1d000 { >>>>> - compatible = "fsl,flexcan-v1.0"; >>>>> + compatible = "fsl,p1010-flexcan", >>>>> + "fsl,flexcan"; >>>> >>>> Ditto >>>> >>>>> reg = <0x1d000 0x1000>; >>>>> interrupts = <61 0x2>; >>>>> interrupt-parent = <&mpic>; >>>>> - fsl,flexcan-clock-divider = <2>; >>>>> }; >>>>> >>>>> L2: l2-cache-controller@20000 { >>>> >>>> Please also correct the node names (not using the number suffix). >>> >>> So the node names should be >>> can@1c000 { >>> can@1d000 { >>> correct? >>> >> [Bhaskar] As there are two CAN controllers on P1010,So won't it be better >> to distinguish it by can0 and can1 instead by simple "can" ? > > It looks like the way to do that is to assign a label to those devices > and then associate the label with an alias. I have no idea how that > works under the hood, but it is the way other files are set up. Take a > look at arch/powerpc/boot/dts/bamboo.dts for how they define the serial > interfaces. > > Grant or Wolfgang, is that the right way to handle the concern about > names or does it have no practical effect with the Linux kernel?
It has not effect. The label is just if you need to reference it via some other means. - k _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
