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

From: Mark Brown
Date: Wed Feb 13 2019 - 07:16:46 EST


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.

> 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.

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