Hello,
On Mon, Dec 16, 2024 at 12:32:04PM -0500, Frank Li wrote:
> From: Luwei Zhou <b45643@xxxxxxxxxxxxx>
>
> 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@xxxxxxxxxxxxx>
> Signed-off-by: Fugang Duan <B38611@xxxxxxxxxxxxx>
> Signed-off-by: Vipul Kumar <vipul_kumar@xxxxxxxxxx>
> Signed-off-by: Dong Aisheng <aisheng.dong@xxxxxxx>
> Signed-off-by: Frank Li <Frank.Li@xxxxxxx>
> ---
> 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
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