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. > > > 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.
