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? > > 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. > > 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. > > 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? -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation -- 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
