media: ts2020: avoid integer overflows on 32 bit machines

commit 81742be14b6a90c9fd0ff6eb4218bdf696ad8e46 upstream.

Before this patch, when compiled for arm32, the signal strength
were reported as:

Lock   (0x1f) Signal= 4294908.66dBm C/N= 12.79dB

Because of a 32 bit integer overflow. After it, it is properly
reported as:

	Lock   (0x1f) Signal= -58.64dBm C/N= 12.79dB

Fixes: 0f91c9d6bab9 ("[media] TS2020: Calculate tuner gain correctly")
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/media/dvb-frontends/ts2020.c b/drivers/media/dvb-frontends/ts2020.c
index a9f6bbea6df368fbea92a47457dec33730bf90c3..103b9c824f1f241e5389ee7b6eaaa574b016caff 100644 (file)
--- a/drivers/media/dvb-frontends/ts2020.c
+++ b/drivers/media/dvb-frontends/ts2020.c
@@ -369,7 +369,7 @@ static int ts2020_read_tuner_gain(struct dvb_frontend *fe, unsigned v_agc,
                gain2 = clamp_t(long, gain2, 0, 13);
                v_agc = clamp_t(long, v_agc, 400, 1100);
 
-               *_gain = -(gain1 * 2330 +
+               *_gain = -((__s64)gain1 * 2330 +
                           gain2 * 3500 +
                           v_agc * 24 / 10 * 10 +
                           10000);
@@ -387,7 +387,7 @@ static int ts2020_read_tuner_gain(struct dvb_frontend *fe, unsigned v_agc,
                gain3 = clamp_t(long, gain3, 0, 6);
                v_agc = clamp_t(long, v_agc, 600, 1600);
 
-               *_gain = -(gain1 * 2650 +
+               *_gain = -((__s64)gain1 * 2650 +
                           gain2 * 3380 +
                           gain3 * 2850 +
                           v_agc * 176 / 100 * 10 -