On Wed, May 28, 2014 at 01:47:50PM +0200, Tomasz Figa wrote: > Moreover, there are already WLAN chips available that can use HSIC as > their host interface and I'm not talking here about some exotic > products, but rather widely recognized products of Broadcom (BCM4335), > Marvell (88W8797) or Qualcomm Atheros (AR6004). > My conclusion is that I see the discussion here being too much focused > on MMC, especially considering the fact that the whole problem doesn't > have anything to do with MMC, which is just used as (one of possible) > host interface. Right, the other example I keep mentioning for this is Slimbus where some sort of external power control is required to trigger enumeration in normal operation for common use cases. > IMHO, all we need here is a way to tell the MMC (or HSIC) core when to > look for a new device and when not (e.g. power down the host controller > completely). Anything else, including proper power sequencing is up to > the platform driver of such non-discoverable device - it's only its host > interface that is discoverable when enabled. I believe this simplistic > approach would lead to much less new code added, better reusability of > code (power sequencing independent of host interface) and no need to > create overly generic code, which usually turns out to be not generic > enough. We then have the problem of working out where that platform driver comes from, for many of these buses the device can be completely described as just a device on the parent bus with some resources connected.
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