ASoC: Avoid wraparound in wm_hubs DC servo correction

If the correction wraps around then a substantial offset would be
introduced.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>

1 files changed, 4 insertions, 2 deletions

diff --git a/sound/soc/codecs/wm_hubs.c b/sound/soc/codecs/wm_hubs.c
index 486bdd21a98a..3729a12b151f 100644
--- a/sound/soc/codecs/wm_hubs.c
+++ b/sound/soc/codecs/wm_hubs.c
@@ -113,13 +113,15 @@ static void calibrate_dc_servo(struct snd_soc_codec *codec)
                 /* HPOUT1L */
                 reg = snd_soc_read(codec, WM8993_DC_SERVO_READBACK_1) &
                         WM8993_DCS_INTEG_CHAN_0_MASK;;
-                reg += hubs->dcs_codes;
+                if (reg + hubs->dcs_codes > 0 && reg + hubs->dcs_codes < 0xff)
+                        reg += hubs->dcs_codes;
                 dcs_cfg = reg << WM8993_DCS_DAC_WR_VAL_1_SHIFT;
 
                 /* HPOUT1R */
                 reg = snd_soc_read(codec, WM8993_DC_SERVO_READBACK_2) &
                         WM8993_DCS_INTEG_CHAN_1_MASK;
-                reg += hubs->dcs_codes;
+                if (reg + hubs->dcs_codes > 0 && reg + hubs->dcs_codes < 0xff)
+                        reg += hubs->dcs_codes;
                 dcs_cfg |= reg;
 
                 /* Do it */