linux/drivers/mmc
Anton Vorontsov a9e58f2573 sdhci: get rid of "frequency too high" flood when using eSDHC
Since commit 8dfd0374be ("MMC core: limit
minimum initialization frequency to 400kHz") MMC core checks for minimum
frequency, and that causes following messages flood when using eSDHC
controllers:

  ...
  mmc0: Minimum clock frequency too high for identification mode
  mmc0: Minimum clock frequency too high for identification mode
  ...

The warnings are legitimate, since if we'd use 133 MHz clocks for standard
SDHCI controllers, we'd not able to scale frequency down to 400 kHz.

But eSDHC controllers have a non-standard SD clock management, so we can
divide clock by 256 * 16, not just 256.

This patch introduces get_min_clock() callback for sdhci core and
implements it for sdhci-of driver, and thus fixes the issue.

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Cc: Matt Fleming <matt@console-pimps.org>
Cc: Ian Molton <ian@mnementh.co.uk>
Cc: "Roberto A. Foglietta" <roberto.foglietta@gmail.com>
Cc: Pierre Ossman <drzeus@drzeus.cx>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-07-29 19:10:36 -07:00
..
card mmc_block: do not DMA to stack 2009-06-13 22:43:01 +02:00
core MMC core: limit minimum initialization frequency to 400kHz 2009-06-13 22:42:57 +02:00
host sdhci: get rid of "frequency too high" flood when using eSDHC 2009-07-29 19:10:36 -07:00
Kconfig mmc: explicitly mention SDIO support in Kconfig 2008-10-12 11:04:36 +02:00
Makefile mmc: Move core functions to subdir 2007-05-01 13:04:18 +02:00