On 12/12/2012 03:13 AM, Daniel Mack wrote: > On 06.12.2012 17:19, Jon Hunter wrote: >> >> 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. > > Any idea yet how we want to continue on this? I'm asking because I'm > leaving for a longer trip by the end of this week, and so anything I > haven't finished until then will have to be postponed until February or > be taken over by someone else :) Thanks for the reminder! So looking at this today, here is what I see when comparing the registers ... omap2430 != omap2420 omap3430 != omap2430 omap3630 == omap3430 omap4430 != omap3430 omap4460 == omap4430 omap543x == omap4430 am335x != omap4430 Therefore, I believe that we need to have the following compatible strings ... ti,omap2420-gpmc ti,omap2430-gpmc ti,omap3430-gpmc (omap3430 & omap3630) ti,omap4430-gpmc (omap4430 & omap4460 & omap543x) ti,am3352-gpmc (am335x devices) Probably worth adding a comment to the Documentation what should be used for which device. Cheers 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
