On Mon, 19 Nov 2018 23:22:45 +0100 Marek Vasut <marek.vasut@xxxxxxxxx> wrote: > On 11/19/2018 11:19 PM, Boris Brezillon wrote: > > On Mon, 19 Nov 2018 23:11:31 +0100 > > Marek Vasut <marek.vasut@xxxxxxxxx> wrote: > > > >> On 11/19/2018 04:21 PM, Boris Brezillon wrote: > >>> On Mon, 19 Nov 2018 16:12:41 +0100 > >>> Marek Vasut <marek.vasut@xxxxxxxxx> wrote: > >>> > >>>> On 11/19/2018 03:43 PM, Boris Brezillon wrote: > >>>>> On Mon, 19 Nov 2018 15:14:07 +0100 > >>>>> Marek Vasut <marek.vasut@xxxxxxxxx> wrote: > >>>>> > >>>>>> On 11/19/2018 03:10 PM, Boris Brezillon wrote: > >>>>>>> On Mon, 19 Nov 2018 14:49:31 +0100 > >>>>>>> Marek Vasut <marek.vasut@xxxxxxxxx> wrote: > >>>>>>> > >>>>>>>> On 11/19/2018 11:01 AM, Mason Yang wrote: > >>>>>>>>> Document the bindings used by the Renesas R-Car D3 RPC controller. > >>>>>>>>> > >>>>>>>>> Signed-off-by: Mason Yang <masonccyang@xxxxxxxxxxx> > >>>>>>>>> --- > >>>>>>>>> .../devicetree/bindings/spi/spi-renesas-rpc.txt | 33 ++++++++++++++++++++++ > >>>>>>>>> 1 file changed, 33 insertions(+) > >>>>>>>>> create mode 100644 Documentation/devicetree/bindings/spi/spi-renesas-rpc.txt > >>>>>>>>> > >>>>>>>>> diff --git a/Documentation/devicetree/bindings/spi/spi-renesas-rpc.txt b/Documentation/devicetree/bindings/spi/spi-renesas-rpc.txt > >>>>>>>>> new file mode 100644 > >>>>>>>>> index 0000000..8286cc8 > >>>>>>>>> --- /dev/null > >>>>>>>>> +++ b/Documentation/devicetree/bindings/spi/spi-renesas-rpc.txt > >>>>>>>>> @@ -0,0 +1,33 @@ > >>>>>>>>> +Renesas R-Car D3 RPC controller Device Tree Bindings > >>>>>>>>> +---------------------------------------------------- > >>>>>>>>> + > >>>>>>>>> +Required properties: > >>>>>>>>> +- compatible: should be "renesas,rpc-r8a77995" > >>>>>>>>> +- #address-cells: should be 1 > >>>>>>>>> +- #size-cells: should be 0 > >>>>>>>>> +- reg: should contain 2 entries, one for the registers and one for the direct > >>>>>>>>> + mapping area > >>>>>>>>> +- reg-names: should contain "rpc_regs" and "dirmap" > >>>>>>>>> +- interrupts: interrupt line connected to the RPC SPI controller > >>>>>>>> > >>>>>>>> Do you also plan to support the RPC HF mode ? And if so, how would that > >>>>>>>> look in the bindings ? > >>>>>>> > >>>>>>> Not sure this approach is still accepted, but that's how we solved the > >>>>>>> problem for the flexcom block [1]. > >>>>>>> > >>>>>>> [1]https://elixir.bootlin.com/linux/v4.20-rc3/source/Documentation/devicetree/bindings/mfd/atmel-flexcom.txt > >>>>>> > >>>>>> That looks pretty horrible. > >>>>>> > >>>>>> In U-Boot we check whether the device hanging under the controller node > >>>>>> is JEDEC SPI flash or CFI flash and based on that decide what the config > >>>>>> of the controller should be (SPI or HF). Not sure that's much better,but > >>>>>> at least it doesn't need extra nodes which do not really represent any > >>>>>> kind of real hardware. > >>>>>> > >>>>> > >>>>> The subnodes are not needed, you can just have a property that tells in > >>>>> which mode the controller is supposed to operate, and the MFD would > >>>>> create a sub-device that points to the same device_node. > >>>> > >>>> Do you even need a dedicated property ? I think you can decide purely on > >>>> what node is hanging under the controller (jedec spi nor or cfi nor). > >>> > >>> Yes, that could work if they have well-known compatibles. As soon as > >>> people start using flash-specific compats (like some people do for > >>> their SPI NORs) it becomes a maintenance burden. > >> > >> Which, on this controller, is very likely never gonna happen. Once it > >> does , we can add a custom property. > >> > >>>>> Or we can have > >>>>> a single driver that decides what to declare (a spi_controller or flash > >>>>> controller), but you'd still have to decide where to place this > >>>>> driver... > >>>> > >>>> I'd definitely prefer a single driver. > >>>> > >>> > >>> Where would you put this driver? I really don't like the idea of having > >>> MTD drivers spread over the tree. Don't know what's Mark's opinion on > >>> this matter. > >> > >> Well, it's both CFI (hyperflash) and SF (well, SPI flash) controller, so > >> where would this go ? > >> > > > > The spi-mem layer is in drivers/spi/ so it could go in drivers/spi/ > > (spi-mem controller) or drivers/mtd/ (CFI controller). > > drivers/mtd is probably a better option, since it's not a generic SPI > controller. > No, spi-mem controller drivers should go in drivers/spi/ even if they don't implement the generic SPI interface (it's allowed to only implement the spi_mem interface). >
