[PATCH v5] iio: humidity: ens210: Fix missing I2C functionality checks

[Salah Triki]

The ENS210 driver uses SMBus transactions (such as byte, word, and block
data reads/writes) during the probe and measurement phases. However, the
initial functionality check only validated a subset of these capabilities,
which could lead to loading failures on adapters requiring SMBus
emulation or native-only controllers.

To ensure compatibility across a wide range of I2C adapters, modify the
functionality check to verify if the adapter supports the required native
operations or, failing that, supports the SMBus emulation layer.

Fixes: c524fbca672e ("iio: humidity: Add support for ENS210")
Signed-off-by: Salah Triki <salah.triki@xxxxxxxxx>
---
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`) to prevent
  loading issues on controllers lacking the emulation flag.

 drivers/iio/humidity/ens210.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/humidity/ens210.c b/drivers/iio/humidity/ens210.c
index 77418d97f30d..159a3c158c9f 100644
--- a/drivers/iio/humidity/ens210.c
+++ b/drivers/iio/humidity/ens210.c
@@ -204,7 +204,10 @@ static int ens210_probe(struct i2c_client *client)
 	if (!i2c_check_functionality(client->adapter,
 				     I2C_FUNC_SMBUS_WRITE_BYTE_DATA |
 				     I2C_FUNC_SMBUS_WRITE_BYTE |
-				     I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
+				     I2C_FUNC_SMBUS_READ_BYTE_DATA |
+				     I2C_FUNC_SMBUS_READ_WORD_DATA |
+				     I2C_FUNC_SMBUS_READ_I2C_BLOCK) &&
+	    !i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_EMUL)) {
 		return dev_err_probe(&client->dev, -EOPNOTSUPP,
 			"adapter does not support some i2c transactions\n");
 	}
-- 
2.43.0