On Tue, Apr 2, 2019 at 3:45 PM Christian Lütke-Stetzkamp <christian@xxxxxxxx> wrote: > There are two other larger differences that I found during my > work. One is that drivers/mmc/host/mtk-sd.c has much more features, > like voltage and clock handling and some support for high speed > modes. I don't know if these features are required/useful for this > device. For what it's worth, I found an old forum post of someone who was dealing with a crashy kernel on their mt7688. They removed the mt7621-mmc driver and hacked the clock code out of the mainline driver. Apparently it worked. I never got around to duplicating their work, however. (I too ran into severe instability problems with the mt7621-mmc driver, but they only appeared in conjunction with using the SLOB allocator. I could never debug it because when JTAG was turned on, the SDMC peripheral was disabled for some reason I never discovered. More info on that if someone is interested.) The correct way to do this would be to have a "compatible" flag that bypassed the clock handling code. I don't think there are any relevant clocks to set up on the MT7628/MT7688 - the MSDC peripheral does not appear in the clock plan. > The other thing is the card detect handling. This driver is > doing the card detect / read only detection on its own, where the in > tree one just uses some default gpio functions there and I don't know > weather this must be changed or weather there is a gpio driver for the > mt7621. There is a "mtk,mt7621-gpio"-compatible GPIO driver available. Probably it would work with GPIO on new hardware that did not to route CD to the CD pin, because the CD pin is muxed using the same "SD card" pin state as the SD data pins. I do not know if it is possible for the GPIO peripheral to read the pin while it is muxed to the SD controller, as would be necessary for existing hardware. George _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
