On 11/25/2013 01:00 PM, Sekhar Nori wrote: > On Thursday 21 November 2013 11:45 PM, Prabhakar Lad wrote: >> From: KV Sujith <sujithkv@xxxxxx> >> >> This patch adds OF parser support for davinci gpio >> driver and also appropriate documentation in gpio-davinci.txt >> located at Documentation/devicetree/bindings/gpio/. >> >> Acked-by: Linus Walleij <linus.walleij@xxxxxxxxxx> >> Acked-by: Rob Herring <rob.herring@xxxxxxxxxxx> >> Signed-off-by: KV Sujith <sujithkv@xxxxxx> >> Signed-off-by: Philip Avinash <avinashphilip@xxxxxx> >> [prabhakar.csengg@xxxxxxxxx: simplified the OF code, removed >> unnecessary DT property and also simplified >> the commit message] >> Signed-off-by: Lad, Prabhakar <prabhakar.csengg@xxxxxxxxx> >> --- >> .../devicetree/bindings/gpio/gpio-davinci.txt | 41 ++++++++++++++ >> drivers/gpio/gpio-davinci.c | 57 ++++++++++++++++++-- >> 2 files changed, 95 insertions(+), 3 deletions(-) >> create mode 100644 Documentation/devicetree/bindings/gpio/gpio-davinci.txt >> >> diff --git a/Documentation/devicetree/bindings/gpio/gpio-davinci.txt b/Documentation/devicetree/bindings/gpio/gpio-davinci.txt >> new file mode 100644 >> index 0000000..a2e839d >> --- /dev/null >> +++ b/Documentation/devicetree/bindings/gpio/gpio-davinci.txt >> @@ -0,0 +1,41 @@ >> +Davinci GPIO controller bindings >> + >> +Required Properties: >> +- compatible: should be "ti,dm6441-gpio" >> + >> +- reg: Physical base address of the controller and the size of memory mapped >> + registers. >> + >> +- gpio-controller : Marks the device node as a gpio controller. >> + >> +- interrupt-parent: phandle of the parent interrupt controller. >> + >> +- interrupts: Array of GPIO interrupt number. Only banked or unbanked IRQs are >> + supported at a time. > > If this is true.. > >> + >> +- ti,ngpio: The number of GPIO pins supported. >> + >> +- ti,davinci-gpio-unbanked: The number of GPIOs that have an individual interrupt >> + line to processor. > > .. then why do you need to maintain this separately? Number of elements > in interrupts property should give you this answer, no? > > There can certainly be devices (past and future) which use a mixture of > banked and unbanked IRQs. So a binding which does not take care of this > is likely to change in future and that is a problem since it brings in > backward compatibility of the binding into picture. > > The right thing would be to define the DT node per-bank similar to what > is done on OMAP rather than for all banks together. That way there can > be a separate property which determines whether that bank supports > direct-mapped or banked IRQs (or that could be inferred if the number of > tuples in the interrupts property is more than one). Number of IRQ can't be simply used to determine type of IRQ - need to handle IRQ names, because each bank(32 gpios) may have up to 2 banked IRQs (one per 16 GPIO). Few things here: - The mixed banked/unbanked functionality has never been supported before. - The Davinci GPIO IP is different from OMAP and has common control registers for all banks. - The proposed approach is more less easy to implement for DT case, but for not-DT case - the platform data will need to be changed significantly (. So, from this point of view, that would be a big change (actually the total driver rewriting). Do you have any thoughts about how it can be done in a simpler way? Actually, the same was proposed by Linus, but we've tried avoid such huge rework - by switching to one irq_domain per all banks for example. Regards, - grygorii -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
