linux-kernel - [PATCH] ASoC: cs42l56: Fix misuse of regmap_update

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Message-Id: <1480439449-15975-1-git-send-email-florian.vaussard@heig-vd.ch>
Date:   Tue, 29 Nov 2016 18:10:49 +0100
From:   Florian Vaussard <florian.vaussard@...il.com>
To:     Brian Austin <brian.austin@...rus.com>,
        Paul Handrigan <Paul.Handrigan@...rus.com>
Cc:     Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>,
        Jaroslav Kysela <perex@...ex.cz>,
        Takashi Iwai <tiwai@...e.com>, alsa-devel@...a-project.org,
        linux-kernel@...r.kernel.org,
        Florian Vaussard <florian.vaussard@...g-vd.ch>
Subject: [PATCH] ASoC: cs42l56: Fix misuse of regmap_update_bits

Using regmap_update_bits(..., mask, 1) with 'mask' following (1 << k)
and k greater than 0 is wrong. Indeed, _regmap_update_bits will perform
(mask & 1), which results in 0 if LSB of mask is 0. Thus the call
regmap_update_bits(..., mask, 1) is in reality equivalent to
regmap_update_bits(..., mask, 0).

In such a case, the correct use is regmap_update_bits(..., mask, mask).

This driver is performing such a mistake with the CS42L56_AIN*_REF_MASK
masks, which equal 0x10, 0x20, 0x40 and 0x80. Fix the driver to make it
consistent with the API. Please note that this change is untested,
as I do not have this piece of hardware. Testers are welcome!

Signed-off-by: Florian Vaussard <florian.vaussard@...g-vd.ch>
---
 sound/soc/codecs/cs42l56.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/sound/soc/codecs/cs42l56.c b/sound/soc/codecs/cs42l56.c
index 3e2c046..cb6ca85 100644
--- a/sound/soc/codecs/cs42l56.c
+++ b/sound/soc/codecs/cs42l56.c
@@ -1277,19 +1277,23 @@ static int cs42l56_i2c_probe(struct i2c_client *i2c_client,
 
 	if (cs42l56->pdata.ain1a_ref_cfg)
 		regmap_update_bits(cs42l56->regmap, CS42L56_AIN_REFCFG_ADC_MUX,
-				   CS42L56_AIN1A_REF_MASK, 1);
+				   CS42L56_AIN1A_REF_MASK,
+				   CS42L56_AIN1A_REF_MASK);
 
 	if (cs42l56->pdata.ain1b_ref_cfg)
 		regmap_update_bits(cs42l56->regmap, CS42L56_AIN_REFCFG_ADC_MUX,
-				   CS42L56_AIN1B_REF_MASK, 1);
+				   CS42L56_AIN1B_REF_MASK,
+				   CS42L56_AIN1B_REF_MASK);
 
 	if (cs42l56->pdata.ain2a_ref_cfg)
 		regmap_update_bits(cs42l56->regmap, CS42L56_AIN_REFCFG_ADC_MUX,
-				   CS42L56_AIN2A_REF_MASK, 1);
+				   CS42L56_AIN2A_REF_MASK,
+				   CS42L56_AIN2A_REF_MASK);
 
 	if (cs42l56->pdata.ain2b_ref_cfg)
 		regmap_update_bits(cs42l56->regmap, CS42L56_AIN_REFCFG_ADC_MUX,
-				   CS42L56_AIN2B_REF_MASK, 1);
+				   CS42L56_AIN2B_REF_MASK,
+				   CS42L56_AIN2B_REF_MASK);
 
 	if (cs42l56->pdata.micbias_lvl)
 		regmap_update_bits(cs42l56->regmap, CS42L56_GAIN_BIAS_CTL,
-- 
2.5.5