Re: [PATCH v8] iio: humidity: ens210: Extend I2C functionality check

[Jonathan Cameron <jic23@kernel.org>]

On Wed, 19 Aug 2026 11:31:09 +0100
Salah Triki <salah.triki@gmail.com> wrote:

> The ENS210 driver uses byte data read/write, word data read, and block
> data read transactions. However, the probe function checks for
> I2C_FUNC_SMBUS_WRITE_BYTE (which is unused) and misses the check for word
> data reads.
> 
> Update the functionality check to strictly match the transactions used by
> the driver by removing the unused flag and adding the missing byte and word
> read capabilities.
> 
> Signed-off-by: Salah Triki <salah.triki@gmail.com>
I am a bit curious about whether any modern smbus capable controllers actually
support only a subset and without that info I don't want to see lots
of patches adding these checks

In this case there was a wrong check though so I'm very happy to see
that tidied!

Applied to the testing branch of iio.git

Thanks

Jonathan

> ---
> Changes since v7:
> - Fixed functionality mask based on code analysis by Stepan Ionichev and
>   Jonathan Cameron:
>   - Removed unused I2C_FUNC_SMBUS_WRITE_BYTE.
>   - Replaced I2C_FUNC_SMBUS_WRITE_BYTE_DATA with I2C_FUNC_SMBUS_BYTE_DATA.
>   - Used I2C_FUNC_SMBUS_READ_WORD_DATA
> 
> 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 | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/iio/humidity/ens210.c b/drivers/iio/humidity/ens210.c
> index 81276195152b..4bdd37e7227b 100644
> --- a/drivers/iio/humidity/ens210.c
> +++ b/drivers/iio/humidity/ens210.c
> @@ -202,8 +202,8 @@ static int ens210_probe(struct i2c_client *client)
>  	int ret;
>  
>  	if (!i2c_check_functionality(client->adapter,
> -				     I2C_FUNC_SMBUS_WRITE_BYTE_DATA |
> -				     I2C_FUNC_SMBUS_WRITE_BYTE |
> +				     I2C_FUNC_SMBUS_BYTE_DATA |
> +				     I2C_FUNC_SMBUS_READ_WORD_DATA |
>  				     I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
>  		return dev_err_probe(&client->dev, -EOPNOTSUPP,
>  			"adapter does not support some i2c transactions\n");