On 5 November 2011 01:27, Olof Johansson <olof@xxxxxxxxx> wrote: > On Thu, Nov 03, 2011 at 02:06:02AM +0530, 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. >> >> Signed-off-by: Thomas Abraham <thomas.abraham@xxxxxxxxxx> >> --- >> .../devicetree/bindings/mmc/linux-mmc-host.txt | 13 ++++++++ >> drivers/mmc/core/host.c | 31 ++++++++++++++++++++ >> include/linux/mmc/host.h | 1 + >> 3 files changed, 45 insertions(+), 0 deletions(-) >> create mode 100644 Documentation/devicetree/bindings/mmc/linux-mmc-host.txt >> >> diff --git a/Documentation/devicetree/bindings/mmc/linux-mmc-host.txt b/Documentation/devicetree/bindings/mmc/linux-mmc-host.txt >> new file mode 100644 >> index 0000000..714b2b1 >> --- /dev/null >> +++ b/Documentation/devicetree/bindings/mmc/linux-mmc-host.txt >> @@ -0,0 +1,13 @@ >> +* Linux MMC Host Controller Capabilities >> + >> +The following bindings can be used in a device node to specify any board >> +specific mmc host controller capabilities. >> + >> +- 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 >> +- linux,mmc_cap_disable - Host can be disabled and re-enabled to save power >> +- linux,mmc_cap_nonremovable - Host is connected to nonremovable media >> +- linux,mmc_cap_erase - Host allows erase/trim commands > > linux-prefixed properties are a big red flag. The device tree should describe > the hardware, not what linux does with the hardware. The vendor-prefixes documentation for device tree bindings includes 'linux' as an option. And I was trying to encode the linux specific host controller capabilities using the above bindings. > > See previous comments about "support-8bit" for encoding exactly the same > hardware capability in a linux-agnostic way. What the sdhci driver chooses to > do with it is up to the driver, and in some cases it means it will set the > capabilities flag. > > Same goes for the other properties. It should not go in as it is > implemented in this patch, it needs to be fixed up. Ok. I will remove all these linux specific bindings and replace with a more generic ones. Bindings will be defined for all the linux defined host capabilities. Non-linux platforms can add additional bindings as required. A function to parse such properties from a controller device node could actually be shared among all the mmc/sd host controller drivers in linux. I will redo this patch and submit again. Thanks Olof for your review and comments. Regards, Thomas. > > > -Olof > -- 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
