linux-kernel - Re: [PATCH 1/2] leds: is31fl319x: Add sdb pin and generate a 5ms low pulse when startup

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: <7c828160-bef6-45b5-60d1-85c6074953c4@ti.com>
Date:   Thu, 6 Aug 2020 10:00:59 -0500
From:   Dan Murphy <dmurphy@...com>
To:     Grant Feng <von81@....com>, <jacek.anaszewski@...il.com>,
        <pavel@....cz>, <robh+dt@...nel.org>, <linux-leds@...r.kernel.org>,
        <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/2] leds: is31fl319x: Add sdb pin and generate a 5ms low
 pulse when startup

Grant

On 8/6/20 1:21 AM, Grant Feng wrote:
> generate a 5ms low pulse on sdb pin when startup, then the chip
> becomes more stable in the complex EM environment.
>
> Signed-off-by: Grant Feng <von81@....com>
> ---
>   drivers/leds/leds-is31fl319x.c | 12 ++++++++++++
>   1 file changed, 12 insertions(+)
>
> diff --git a/drivers/leds/leds-is31fl319x.c b/drivers/leds/leds-is31fl319x.c
> index ca6634b8683c..b4f70002cec9 100644
> --- a/drivers/leds/leds-is31fl319x.c
> +++ b/drivers/leds/leds-is31fl319x.c
> @@ -16,6 +16,8 @@
>   #include <linux/of_device.h>
>   #include <linux/regmap.h>
>   #include <linux/slab.h>
> +#include <linux/delay.h>
> +#include <linux/gpio/consumer.h>
>   
>   /* register numbers */
>   #define IS31FL319X_SHUTDOWN		0x00
> @@ -61,6 +63,7 @@
>   struct is31fl319x_chip {
>   	const struct is31fl319x_chipdef *cdef;
>   	struct i2c_client               *client;
> +	struct gpio_desc		*sdb_pin;
>   	struct regmap                   *regmap;
>   	struct mutex                    lock;
>   	u32                             audio_gain_db;
> @@ -265,6 +268,15 @@ static int is31fl319x_parse_dt(struct device *dev,
>   		is31->audio_gain_db = min(is31->audio_gain_db,
>   					  IS31FL319X_AUDIO_GAIN_DB_MAX);
>   
> +	is31->sdb_pin = gpiod_get(dev, "sdb", GPIOD_ASIS);

Since this is optional maybe use devm_gpiod_get_optional.

If this is required for stability then if the GPIO is not present then 
the parse_dt should return the error.

And use the devm_gpiod_get call.  Otherwise you are missing the 
gpiod_put when exiting or removing the driver.

Dan