On Wed, Jun 12, 2019 at 04:09:47PM +0300, Adrian Hunter wrote: > On 10/06/19 9:53 PM, Raul E Rangel wrote: > > The O2 controller supports 8-bit EMMC access. mmc_select_bus_width() > > will be used to determine if the MMC supports 8-bit or 4-bit access. > > The problem is that the bit indicates a host controller capability, not how > many data lines there actually are on the board. Will this break something > that does not have 8 lines? So I asked the controller vendor about that: > The capability shows the host controller can support 1,4,and 8 bit bus > data transfer but it also depends on if HW can support it. Driver or FW > should implement the bus testing procedure that is defined in A.6.3.a > in JESD84-B51 spec to decide the real bus width that is supported in HW. This seems to be what `mmc_select_bus_width()` is doing. I don't actually have any 4-bit hardware to test with though. Thanks for the review!
