Re: [PATCH v7] iio: humidity: ens210: Extend I2C functionality check

[Jonathan Cameron <jic23@kernel.org>]

On Thu, 14 May 2026 09:41:54 +0100
Salah Triki <salah.triki@gmail.com> wrote:

> The ENS210 driver requires several specific SMBus protocols to operate:
> - WRITE_BYTE for sending commands.
> - BYTE_DATA and WORD_DATA for register access.
> - I2C_BLOCK_DATA for reading humidity/temperature results.
> 
> Update the probe function to explicitly check for these required
> functionalities using standard macros. This ensures the driver only
> binds to adapters that support the necessary transaction types.
> 
> Signed-off-by: Salah Triki <salah.triki@gmail.com>
> ---
> Changes since v6:
> - Replaced the incorrect use of I2C_FUNC_SMBUS_EMUL with an explicit 
>   list of required SMBus functionalities as requested by Jonathan Cameron.
> - Used combined macros (BYTE_DATA, WORD_DATA) to simplify the check.
> 
> Changes since v5:
> - Changed patch title from "Fix missing I2C functionality checks" to
>   "Simplify I2C functionality check" to reflect the new approach.
> - Dropped the Fixes tag as the change is now considered hardening rather
>   than a bug fix.
> - Replaced individual functionality checks with a single check for
>   I2C_FUNC_SMBUS_EMUL as suggested by Jonathan Cameron.
> 
> Changes since v4:
> - Fixed the alignment and indentation of the I2C functionality check
>   per Andy's review.
> 
> Changes since v3:
> - Fixed the alignment and indentation of the I2C functionality check
>   per Andy's review.
> 
> Changes since v2:
> - Fixed the alignment and indentation of the I2C functionality check
>   per Maxime's review.
> 
> Changes since v1:
> - Updated the I2C functionality test to check for both required native
>   operations and SMBus emulation (`I2C_FUNC_SMBUS_EMUL`)
>  drivers/iio/humidity/ens210.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/iio/humidity/ens210.c b/drivers/iio/humidity/ens210.c
> index 77418d97f30d..d209f30d61ed 100644
> --- a/drivers/iio/humidity/ens210.c
> +++ b/drivers/iio/humidity/ens210.c
> @@ -204,6 +204,8 @@ static int ens210_probe(struct i2c_client *client)
>  	if (!i2c_check_functionality(client->adapter,
>  				     I2C_FUNC_SMBUS_WRITE_BYTE_DATA |
Sashiko pointed this out... Take a look at definition of I2C_FUNC_SMBUS_BYTE_DATA
and consider if the line above makes sense.  Check for other instances of
this.
>  				     I2C_FUNC_SMBUS_WRITE_BYTE |
> +				     I2C_FUNC_SMBUS_BYTE_DATA |
> +				     I2C_FUNC_SMBUS_WORD_DATA |
Sashiko suggests this one is tighter than needed.  Might be right - I didn't check!
https://sashiko.dev/#/patchset/20260514084154.298154-1-salah.triki%40gmail.com
>  				     I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
>  		return dev_err_probe(&client->dev, -EOPNOTSUPP,
>  			"adapter does not support some i2c transactions\n");