On 12/05/2012 05:24 PM, Grant Likely wrote: > On Wed, 5 Dec 2012 16:33:48 -0600, Jon Hunter <jon-hunter@xxxxxx> wrote: >> Hi Grant, >> >> On 12/05/2012 04:22 PM, Grant Likely wrote: >>> On Wed, 5 Dec 2012 20:09:31 +0100, Daniel Mack <zonque@xxxxxxxxx> wrote: >>>> This patch adds basic DT bindings for OMAP GPMC. >>>> >>>> The actual peripherals are instantiated from child nodes within the GPMC >>>> node, and the only type of device that is currently supported is NAND. >>>> >>>> Code was added to parse the generic GPMC timing parameters and some >>>> documentation with examples on how to use them. >>>> >>>> Successfully tested on an AM33xx board. >>>> >>>> Signed-off-by: Daniel Mack <zonque@xxxxxxxxx> >>>> --- >>>> Documentation/devicetree/bindings/bus/ti-gpmc.txt | 77 ++++++++++ >>>> .../devicetree/bindings/mtd/gpmc-nand.txt | 76 +++++++++ >>>> arch/arm/mach-omap2/gpmc.c | 171 ++++++++++++++++++++- >>>> 3 files changed, 323 insertions(+), 1 deletion(-) >>>> create mode 100644 Documentation/devicetree/bindings/bus/ti-gpmc.txt >>>> create mode 100644 Documentation/devicetree/bindings/mtd/gpmc-nand.txt >>>> >>>> diff --git a/Documentation/devicetree/bindings/bus/ti-gpmc.txt b/Documentation/devicetree/bindings/bus/ti-gpmc.txt >>>> new file mode 100644 >>>> index 0000000..7d2a645 >>>> --- /dev/null >>>> +++ b/Documentation/devicetree/bindings/bus/ti-gpmc.txt >>>> @@ -0,0 +1,77 @@ >>>> +Device tree bindings for OMAP general purpose memory controllers (GPMC) >>>> + >>>> +The actual devices are instantiated from the child nodes of a GPMC node. >>>> + >>>> +Required properties: >>>> + >>>> + - compatible: Should be set to "ti,gpmc" >>> >>> Please, be specific. Use something like "ti,am3340-gpmc" or >>> "ti,omap3430-gpmc". The compatible property is a list so that new >>> devices can claim compatibility with old. Compatible strings that are >>> overly generic are a pet-peave of mine. >> >> We aim to use the binding for omap2,3,4,5 as well as the am33xx devices >> (which are omap based). Would it be sufficient to have "ti,omap2-gpmc" >> implying all omap2+ based devices or should we have a compatible string >> for each device supported? > > Are they each register-level compatible with one another? They are not 100% register compatible. There are a couple fields in the binding that are only applicable to OMAP3+ devices. > The general recommended approach here is to make subsequent silicon > claim compatibility with the first compatible implementation. > > So, for an am3358 board: > compatible = "ti,am3358-gpmc", "ti,omap2420-gpmc"; > > Essentially, what this means is that "ti,omap2420-gpmc" is the generic > value instead of "omap2-gpmc". The reason for this is so that the value > is anchored against a specific implementation, and not against something > completely imaginary or idealized. If a newer version isn't quite > compatible with the omap2420-gpmc, then it can drop the compatible claim > and the driver really should be told about the new device. Ok, gotcha! I will do a register comparison and may be recommend to Daniel which compatible strings we will need. Thanks! Jon -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
