[PATCH] mmc: sdhci-omap: Fix Tuning procedure for temperatures < -20C

[Faiz Abbas]

According to the App note[1] detailing the tuning algorithm, for
temperatures < -20C, the initial tuning value should be min(largest
value in LPW - 24, ceil(13/16 ratio of LPW)). The largest value in
LPW is (max_window + 4 * (max_len - 1)) and not (max_window + 4 * max_len)
itself. Fix this implementation.

[1] http://www.ti.com/lit/an/spraca9b/spraca9b.pdf

Fixes: 961de0a856e3 ("mmc: sdhci-omap: Workaround errata regarding
SDR104/HS200 tuning failures (i929)")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Faiz Abbas <faiz_abbas@xxxxxx>
---
 drivers/mmc/host/sdhci-omap.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mmc/host/sdhci-omap.c b/drivers/mmc/host/sdhci-omap.c
index 41c2677c587f..083e7e053c95 100644
--- a/drivers/mmc/host/sdhci-omap.c
+++ b/drivers/mmc/host/sdhci-omap.c
@@ -372,7 +372,7 @@ static int sdhci_omap_execute_tuning(struct mmc_host *mmc, u32 opcode)
 	 * on temperature
 	 */
 	if (temperature < -20000)
-		phase_delay = min(max_window + 4 * max_len - 24,
+		phase_delay = min(max_window + 4 * (max_len - 1) - 24,
 				  max_window +
 				  DIV_ROUND_UP(13 * max_len, 16) * 4);
 	else if (temperature < 20000)
-- 
2.19.2