Re: Applied "spi: Add Renesas R-Car Gen3 RPC-IF SPI controller driver" to the spi tree

From: Marek Vasut
Date: Wed Feb 13 2019 - 07:37:38 EST


On 2/13/19 1:16 PM, Mark Brown wrote:
> On Wed, Feb 13, 2019 at 04:25:32PM +0800, masonccyang@xxxxxxxxxxx wrote:
>
>> From current mainline branch, MFD seems support the device which is on
>> the same hardware bus(i.e, I2C, SPI, MMIO and SPMI)for multi-function
>> by Read/Write the common same registers.
>
> That's most MFDs but there are some that do some level of enumeration
> (even if it's just looking at the device ID that got registered) to
> decide what subdevices get registered, that's what people are suggesting
> here I think.

Right. Although I think some of the code could be shared between the SPI
and HF modes.

>> I am checking and not sure if MMIO of MFD could support RPC-IF for
>> different hardware bus on SPI and CFI.
>> I also doubt if this method is a correct solution for RPC-IF works
>> either in SPI mode or CFI mode.
>
> For MMIO devices MFD just passes through the parent resources.
>


--
Best regards,
Marek Vasut