linux-kernel - [PATCH 2/2] ASoC: pcm3168a: Update the RST gpio handling to align with documentation

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20191120131753.6831-3-peter.ujfalusi@ti.com>
Date:   Wed, 20 Nov 2019 15:17:53 +0200
From:   Peter Ujfalusi <peter.ujfalusi@...com>
To:     <broonie@...nel.org>, <lgirdwood@...il.com>
CC:     <alsa-devel@...a-project.org>, <kuninori.morimoto.gx@...esas.com>,
        <linus.walleij@...aro.org>, <robh+dt@...nel.org>,
        <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: [PATCH 2/2] ASoC: pcm3168a: Update the RST gpio handling to align with documentation

The RST (reset-gpios) is low active so the driver must handle it
accordingly.

Add comments to explain clearly how the line is used.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@...com>
---
 sound/soc/codecs/pcm3168a.c | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/sound/soc/codecs/pcm3168a.c b/sound/soc/codecs/pcm3168a.c
index f3475134b519..9711fab296eb 100644
--- a/sound/soc/codecs/pcm3168a.c
+++ b/sound/soc/codecs/pcm3168a.c
@@ -707,11 +707,15 @@ int pcm3168a_probe(struct device *dev, struct regmap *regmap)
 	dev_set_drvdata(dev, pcm3168a);
 
 	/*
-	 * Request the RST gpio line as non exclusive as the same reset line
-	 * might be connected to multiple pcm3168a codec
+	 * Request the reset (connected to RST pin) gpio line as non exclusive
+	 * as the same reset line might be connected to multiple pcm3168a codec
+	 *
+	 * The RST is low active, we want the GPIO line to be high initially, so
+	 * request the initial level to LOW which in practice means DEASSERTED:
+	 * The deasserted level of GPIO_ACTIVE_LOW is HIGH.
 	 */
-	pcm3168a->gpio_rst = devm_gpiod_get_optional(dev, "rst",
-						GPIOD_OUT_HIGH |
+	pcm3168a->gpio_rst = devm_gpiod_get_optional(dev, "reset",
+						GPIOD_OUT_LOW |
 						GPIOD_FLAGS_BIT_NONEXCLUSIVE);
 	if (IS_ERR(pcm3168a->gpio_rst)) {
 		ret = PTR_ERR(pcm3168a->gpio_rst);
@@ -814,7 +818,13 @@ void pcm3168a_remove(struct device *dev)
 {
 	struct pcm3168a_priv *pcm3168a = dev_get_drvdata(dev);
 
-	gpiod_set_value_cansleep(pcm3168a->gpio_rst, 0);
+	/*
+	 * The RST is low active, we want the GPIO line to be low when the
+	 * driver is removed, so set level to 1 which in practice means
+	 * ASSERTED:
+	 * The asserted level of GPIO_ACTIVE_LOW is LOW.
+	 */
+	gpiod_set_value_cansleep(pcm3168a->gpio_rst, 1);
 	pm_runtime_disable(dev);
 #ifndef CONFIG_PM
 	pcm3168a_disable(dev);
-- 
Peter

Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki