mmc: Change board_mmc_getcd() function prototype.

The new API no longer uses the extra cd parameter that was used to store
the card presence state. Instead, this information is returned via the
function's return value. board_mmc_getcd() returns -1 to indicate that
no card-detection mechanism is implemented; 0 indicates that no card is
present and 1 is returned if it was detected that a card is present.

The rationale for this change can be found in the following email
thread:

	http://lists.denx.de/pipermail/u-boot/2011-November/110180.html

In summary, the old API was not consistent with the rest of the MMC API
which always passes a struct mmc as the first parameter. Furthermore the
cd parameter was used to mean "card absence" in some implementations and
"card presence" in others.

Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Tested-by: Jason Liu <jason.hui@linaro.org>

1 files changed, 2 insertions, 10 deletions

diff --git a/doc/README.atmel_mci b/doc/README.atmel_mci
index dee0cf0..0cbd909 100644
--- a/doc/README.atmel_mci
+++ b/doc/README.atmel_mci
@@ -59,17 +59,9 @@ int board_mmc_init(bd_t *bd)
 }
 
 /* this is a weak define that we are overriding */
-int board_mmc_getcd(u8 *cd, struct mmc *mmc)
+int board_mmc_getcd(struct mmc *mmc)
 {
-	/*
-	 * the only currently existing use of this function
-	 * (fsl_esdhc.c) suggests this function must return
-	 * *cs = TRUE if a card is NOT detected -> in most
-	 * cases the value of the pin when the detect switch
-	 * closes to GND
-	 */
-	*cd = at91_get_gpio_value (CONFIG_SYS_MMC_CD_PIN) ? 1 : 0;
-	return 0;
+	return !at91_get_gpio_value(CONFIG_SYS_MMC_CD_PIN);
 }
 
 #endif