forked from luck/tmp_suning_uos_patched
55556da012
Fix handling of low voltage MMC cards. The latest MMC and SD specs both agree that support for low-voltage operations is indicated by bit 7 in the OCR. The MMC spec states that the low voltage range is 1.65-1.95V while the SD spec leaves the actual voltage range undefined - meaning that there is still no such thing as a low voltage SD card. However, an old Sandisk spec implied that bits 7.0 represented voltages below 2.0V in 1V or 0.5V increments, and the code was accordingly written with that expectation. This confusion meant that host drivers attempting to support the typical low voltage (1.8V) would set the wrong bits in the host OCR mask (usually bits 5 and/or 6) resulting in the the low voltage mode never being used. This change corrects the low voltage range and adds sanity checks on the reserved bits (0-6) and for SD cards that claim to support low-voltage operations. Signed-off-by: Philip Langdale <philipl@overt.org> Signed-off-by: Pierre Ossman <drzeus@drzeus.cx> |
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