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Date: Tue, 18 Mar 2014 17:31:50 +0100 From: Laurent Pinchart <laurent.pinchart@...asonboard.com> To: Ben Dooks <ben.dooks@...ethink.co.uk> Cc: Mark Rutland <mark.rutland@....com>, "linux-kernel@...ts.codethink.co.uk" <linux-kernel@...ts.codethink.co.uk>, "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>, "netdev@...r.kernel.org" <netdev@...r.kernel.org>, "f.fainelli@...il.com" <f.fainelli@...il.com> Subject: Re: [PATCH] phy: micrel: add of configuration for LED mode On Tuesday 18 March 2014 17:21:04 Ben Dooks wrote: > On 18/03/14 17:11, Laurent Pinchart wrote: > > On Tuesday 18 March 2014 16:56:06 Laurent Pinchart wrote: > >> On Thursday 27 February 2014 10:30:51 Ben Dooks wrote: > >>> On 27/02/14 09:15, Mark Rutland wrote: > >>>> On Wed, Feb 26, 2014 at 11:48:00AM +0000, Ben Dooks wrote: > >>>>> Add support for the led-mode property for the following PHYs > >>>>> which have a single LED mode configuration value. > >>>>> > >>>>> KSZ8001 and KSZ8041 which both use register 0x1e bits 15,14 and > >>>>> KSZ8021, KSZ8031 and KSZ8051 which use register 0x1f bits 5,4 > >>>>> to control the LED configuration. > >>>>> > >>>>> Signed-off-by: Ben Dooks <ben.dooks@...ethink.co.uk> > >>>>> --- > >>>>> > >>>>> Documentation/devicetree/bindings/net/micrel.txt | 18 +++++++++ > >>>>> drivers/net/phy/micrel.c | 49 > >>>>> ++++++++++++++-- > >>>>> 2 files changed, 63 insertions(+), 4 deletions(-) > >>>>> create mode 100644 Documentation/devicetree/bindings/net/micrel.txt > >>>>> > >>>>> diff --git a/Documentation/devicetree/bindings/net/micrel.txt > >>>>> b/Documentation/devicetree/bindings/net/micrel.txt new file mode > >>>>> 100644 > >>>>> index 0000000..98a3e61 > >>>>> --- /dev/null > >>>>> +++ b/Documentation/devicetree/bindings/net/micrel.txt > >>>>> @@ -0,0 +1,18 @@ > >>>>> +Micrel PHY properties. > >>>>> + > >>>>> +These properties cover the base properties Micrel PHYs. > >>>>> + > >>>>> +Optional properties: > >>>>> + > >>>>> + - micrel,led-mode : LED mode value to set for PHYs with configurable > >>>>> LEDs. > >>>>> + > >>>>> + Configure the LED mode with single value. The list of > >>>>> PHYs and > >>>>> + the bits that are currently supported: > >>>>> + > >>>>> + KSZ8001: register 0x1e, bits 15..14 > >>>>> + KSZ8041: register 0x1e, bits 15..14 > >>>>> + KSZ8021: register 0x1f, bits 5..4 > >>>>> + KSZ8031: register 0x1f, bits 5..4 > >>>>> + KSZ8051: register 0x1f, bits 5..4 > >>>>> + > >>>>> + See the respective PHY datasheet for the mode values. > >>>> > >>>> What do these mean, roughly,, and why can the kernel not decide how to > >>>> cnofigure these? > >>> > >>> Board specific, in the case of the Lager one of the LEDs is connected > >>> to the ethernet mac block to indicate link, however the default mode > >>> is not for just "Link" so we have to change it. > >>> > >>>> In general we prefer to not place raw register values in the DT, and > >>>> I'd > >>>> like to know why we'd have to here. > >>> > >>> I could copy out stuff from the data-sheet, but I was trying to avoid a > >>> copy and paste job. > >> > >> I quite agree with Mark here, I would prefer not to list register values > >> in > >> DT bindings. However, the hardware hardware diversity doesn't help us > >> abstracting LED modes. > >> > >> The following table summarizes LED usage options. > >> > >> Device Mode LED usage > >> ------------------------------------------------------------------------- > >> --- 8001 (LED[3:0]) 00 Collision / Full-Duplex / Speed / > >> Link/Activity>> > >> 01 Activity / Full-Duplex/Collision / Speed / Link > >> 10 Activity / Full-Duplex / 100Mbps Link / 10Mbps > >> Link > >> 11 Reserved > >> > >> 80[23]1 (LED[0]) 00 Link/Activity > >> 01 Link > >> 10 Reserved > >> 11 Reserved > >> > >> 80[45]1 (LED[1:0]) 00 Speed / Link/Activity > >> 01 Activity / Link > >> 10 Reserved > >> 11 Reserved > >> > >> While LED mode could be described by LED0 mode using "link-activity" or > >> "link" strings for the 80[2345]1 chips, the 8001 makes that slightly more > >> complex and shows that future chips might not conform to any scheme we > >> come up with now. > >> > >> I thus have no strong preference for a string-based mode description over > >> using an integer. However, if we keep the integer value, I wouldn't use > >> the register value directly, but would instead use the mode field value > >> as an integer in the 0-3 range. This would remove knowledge of the PHY > >> control register layout from the DT node content, and bring more > >> consistency to the values. > > > > And I realize that this is what you've done already in the implementation > > :-/ I'll send a patch to clarify the DT bindings documentation if you > > don't mind, after hearing Mark's opinion on the issue. > > Do we need strings for what is basically a single-setup post reset which it > makes no sense for the user to ever update? If it was a standard setting I would have voted to try and standardize the values. As it isn't, we probably don't. What would you think about defining macros for the LED mode values somewhere in include/dt-bindings/ ? -- Regards, Laurent Pinchart -- 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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