On Wed, Jul 16, 2014 at 11:21:57AM -0700, Stephen Boyd wrote: > On 07/15/14 20:26, Greg KH wrote: > > Hi Stephen. > > > > I had some people ask me about a sdio userspace interface, and ran > > across the chdio.c file as found in the MSM android kernel trees: > > You mean csdio.c right? Ick, yes, sorry about that. > > > > https://android.googlesource.com/kernel/msm/+/57b74303d6f033ab04be039379f6661337fb9279 > > As you can see in the commit text there, the commit I authored is > actually a squash of three patches from some previous android kernel > that we did (looks like it was android-msm-2.6.35) and it's been almost > 4 years since those patches were written. The three original commits > weren't authored by me so I really don't know the intimate details of > this driver. Yes, I know you didn't write this version, but you did the "mushing together", which was nice of you, and presumably you did it for a good reason :) > > Any reason why this hasn't been submitted upstream? Or has it, and was > > it rejected? > > I don't believe we ever submitted this upstream. Why not? > > Also, what userspace code uses this? Is there some android-specific > > code somewhere that does a weird mix of sysfs and char control of the > > hardware? And what type of SDIO devices are controlled with this? > > If I recall correctly this driver is for communicating with an external > modem (in this case it was the Gobi 9k). We used the sdio interface to > do some IPC stuff with the modem over sdio, mainly because back then the > SoC didn't have an LTE capable modem, but the Gobi modem was LTE > capable. Slap the two chips together and you have an LTE phone while you > wait for us to deliver the first SoC with an integrated LTE modem (msm8960). > > The userspace component is the same proprietary software that's used to > make phone calls on android phones. I'd have to go dig around to find > that code and confirm if it's using sysfs and char control. I'd rather > not spend the time digging so let's assume it's doing that unless you > have a more specific question in mind? My specific question is why 2 different interfaces? Some people are looking at a way to do SDIO from userspace, if needed, and I was pointed at this driver, and wanted to figure out why it never was merged. If it's useful, and people are using it in phones today, that's a good reason to merge it in, right? So, any objection for me taking it as-is, as long as my audit of the code passes? thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
