linux-kernel - Re: [PATCH v2 1/1] input: mma8450: Add chip ID check in probe

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] [day] [month] [year] [list]

Message-ID: <jyt32ymjqq6iqvzkx7wvoxlhozgkvv74peh47cfl2jyqcl7qko@azc4m2hbi4bp>
Date: Tue, 17 Dec 2024 10:00:49 +0100
From: Uwe Kleine-König <u.kleine-koenig@...gutronix.de>
To: Frank Li <Frank.Li@....com>
Cc: Dmitry Torokhov <dmitry.torokhov@...il.com>, 
	Dong Aisheng <aisheng.dong@....com>, Fugang Duan <B38611@...escale.com>, 
	Luwei Zhou <b45643@...escale.com>, 
	"open list:INPUT (KEYBOARD, MOUSE, JOYSTICK, TOUCHSCREEN)..." <linux-input@...r.kernel.org>, open list <linux-kernel@...r.kernel.org>, imx@...ts.linux.dev
Subject: Re: [PATCH v2 1/1] input: mma8450: Add chip ID check in probe

Hello,

On Mon, Dec 16, 2024 at 12:32:04PM -0500, Frank Li wrote:
> From: Luwei Zhou <b45643@...escale.com>
> 
> Prevent continuous polling error logs by adding a chip ID check in the
> probe  function. This ensures the driver only proceeds when the mma8450 is
> present, avoiding issues in scenarios like missing add-on cards.
> 
> Signed-off-by: Luwei Zhou <b45643@...escale.com>
> Signed-off-by: Fugang Duan <B38611@...escale.com>
> Signed-off-by: Vipul Kumar <vipul_kumar@...tor.com>
> Signed-off-by: Dong Aisheng <aisheng.dong@....com>
> Signed-off-by: Frank Li <Frank.Li@....com>
> ---
> change from v1 to v2
> - Use  *adapter = c->adapter
> - Use if (!i2c_check_functionality())
> ---
>  drivers/input/misc/mma8450.c | 13 ++++++++++++-
>  1 file changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/input/misc/mma8450.c b/drivers/input/misc/mma8450.c
> index 08412239b8e69..a1adb49fb5f33 100644
> --- a/drivers/input/misc/mma8450.c
> +++ b/drivers/input/misc/mma8450.c
> @@ -38,6 +38,8 @@
>  
>  #define MMA8450_CTRL_REG1	0x38
>  #define MMA8450_CTRL_REG2	0x39
> +#define MMA8450_ID		0xc6
> +#define MMA8450_WHO_AM_I	0x0f
>  
>  static int mma8450_read(struct i2c_client *c, unsigned int off)
>  {
> @@ -148,8 +150,17 @@ static void mma8450_close(struct input_dev *input)
>   */
>  static int mma8450_probe(struct i2c_client *c)
>  {
> +	struct i2c_adapter *adapter = c->adapter;
>  	struct input_dev *input;
> -	int err;
> +	int err, client_id;
> +
> +	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_BYTE_DATA))
> +		return dev_err_probe(&c->dev, -EINVAL, "I2C adapter can't support SMBUS BYTE");
> +
> +	client_id = i2c_smbus_read_byte_data(c, MMA8450_WHO_AM_I);
> +	if (client_id != MMA8450_ID)
> +		return dev_err_probe(&c->dev, -EINVAL, "read chip ID 0x%x is not equal to 0x%x!\n",
> +				     client_id, MMA8450_ID);

i2c_smbus_read_byte_data() might return a negative errno. So the right
handling is:

	client_id = i2c_smbus_read_byte_data(c, MMA8450_WHO_AM_I);
	if (client_id < 0)
		return dev_err_probe(&c->dev, client_id, "Failed to read chip ID\n");
	if (client_id != MMA8450_ID)
		return dev_err_probe(&c->dev, -EINVAL, "read chip ID 0x%x is not equal to 0x%x!\n",
				     client_id, MMA8450_ID);

Best regards
Uwe

Download attachment "signature.asc" of type "application/pgp-signature" (489 bytes)