On 5 October 2011 21:25, Stephen Warren <swarren@xxxxxxxxxx> wrote: > Thomas Abraham wrote at Wednesday, October 05, 2011 8:28 AM: >> On 5 October 2011 18:59, Rob Herring <robherring2@xxxxxxxxx> wrote: >> > On 10/05/2011 05:13 AM, Thomas Abraham wrote: >> >> Device nodes representing sd/mmc controllers in a device tree would include >> >> mmc host controller capabilities. Add support for parsing of mmc host >> >> controller capabilities included in device nodes. > ... >> >> +- linux,mmc_cap_4_bit_data - host can do 4 bit transfers >> >> +- linux,mmc_cap_mmc_highspeed - host can do MMC high-speed timing >> >> +- linux,mmc_cap_sd_highspeed - host can do SD high-speed timing >> >> +- linux,mmc_cap_needs_poll - host needs polling for card detection >> >> +- linux,mmc_cap_8_bit_data - host can do 8 bit transfer >> > >> > "sdhci,1-bit-only" already exists as a binding. Perhaps add >> > "sdhci,4-bit-only". No property then means can do 8-bit. >> >> Ok. But that would remain just as sdhci host controller capability and >> will not be applicable to other types of host controllers. > > Just as an FYI, NVIDIA's SDHCI controller bindings use property > "support-8bit" to indicate 8-bit support. A similar property could be > used for 4-bit support too. In this case, the binding would be applicable only to nVidia's SDHCI controller. And this binding would select MMC_CAP_8_BIT_DATA in the sdhci-tegra driver. There are sdhci drivers that can accept host capabilities via platform data. The MMC_CAP_XXX macros in linux/mmc/host.h file are usuable across host controllers and some of them are supplied as platform data for non-device tree platforms. So, bindings for MMC_CAP_XXX macros can be defined which any host controller supporting device tree could use. Host controllers could use the mmc_of_parse_host_caps() helper function (listed in this patch) to parse all the bindings for MMC_CAP_XXX available in the device node. I would like to retain this patch in this series but if there is a definite no, then I will drop it. Please let me know your opinion. Thanks, Thomas. > > -- > nvpublic > > -- 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
