From 282d5f0567be5abcc57a38ada569460ef63b5be9 Mon Sep 17 00:00:00 2001
From: Chuanxiao Dong <chuanxiao.dong@intel.com>
Date: Thu, 21 Jan 2016 13:57:51 +0100
Subject: [PATCH] mmc: debugfs: Add a restriction to mmc debugfs clock setting

commit e5905ff1281f0a0f5c9863c430ac1ed5faaf5707 upstream.

Clock frequency values written to an mmc host should not be less than
the minimum clock frequency which the mmc host supports.

Signed-off-by: Yuan Juntao <juntaox.yuan@intel.com>
Signed-off-by: Pawel Wodkowski <pawelx.wodkowski@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/mmc/core/debugfs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mmc/core/debugfs.c b/drivers/mmc/core/debugfs.c
index 154aced0b91b..705586dcd9fa 100644
--- a/drivers/mmc/core/debugfs.c
+++ b/drivers/mmc/core/debugfs.c
@@ -220,7 +220,7 @@ static int mmc_clock_opt_set(void *data, u64 val)
 	struct mmc_host *host = data;
 
 	/* We need this check due to input value is u64 */
-	if (val > host->f_max)
+	if (val != 0 && (val > host->f_max || val < host->f_min))
 		return -EINVAL;
 
 	mmc_claim_host(host);