[PATCH 4.4 016/131] mmc: debugfs: Add a restriction to mmc debugfs clock setting

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Chuanxiao Dong <chuanxiao.dong@xxxxxxxxx>

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@xxxxxxxxx>
Signed-off-by: Pawel Wodkowski <pawelx.wodkowski@xxxxxxxxx>
Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/mmc/core/debugfs.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/mmc/core/debugfs.c
+++ b/drivers/mmc/core/debugfs.c
@@ -220,7 +220,7 @@ static int mmc_clock_opt_set(void *data,
 	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);