sdhci: Add support for hosts that are only capable of 1-bit transfers

Some hosts (hardware configurations, or particular SD/MMC slots) may
not support 4-bit bus. For example, on MPC8569E-MDS boards we can
switch between serial (1-bit only) and nibble (4-bit) modes, thought
we have to disable more peripherals to work in 4-bit mode.

Along with some small core changes, this patch modifies sdhci-of
driver, so that now it looks for "sdhci,1-bit-only" property in the
device-tree, and if specified we enable a proper quirk.

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Pierre Ossman <pierre@ossman.eu>
This commit is contained in:
Anton Vorontsov 2009-06-18 00:14:08 +04:00 committed by Pierre Ossman
parent 04ac2f46d6
commit 5fe23c7f51
4 changed files with 11 additions and 1 deletions

View file

@ -10,6 +10,8 @@ Required properties:
- interrupts : should contain eSDHC interrupt.
- interrupt-parent : interrupt source phandle.
- clock-frequency : specifies eSDHC base clock frequency.
- sdhci,1-bit-only : (optional) specifies that a controller can
only handle 1-bit data transfers.
Example: