Re: [PATCH v4 3/6] iio: adc: ad7173: refactor ain and vref selection

["Ceclan, Dumitru" <mitrutzceclan@gmail.com>]

On 03/06/2024 19:00, David Lechner wrote:
> On 6/3/24 8:08 AM, Ceclan, Dumitru wrote:
>> On 03/06/2024 16:00, Nuno Sá wrote:
>>> On Sat, 2024-06-01 at 19:49 +0100, Jonathan Cameron wrote:
>>>> On Fri, 31 May 2024 22:42:29 +0300
>>>> Dumitru Ceclan via B4 Relay <devnull+dumitru.ceclan.analog.com@kernel.org> wrote:
>>>>
>>>>> From: Dumitru Ceclan <dumitru.ceclan@analog.com>
>>>>>
>>>>> Move validation of analog inputs and reference voltage selection to
>>>>> separate functions to reduce the size of the channel config parsing
>>>>> function and improve readability.
>>>>> Add defines for the number of analog inputs in a channel.
>>>>>
>>>>> Reviewed-by: David Lechner <dlechner@baylibre.com>
>>>>> Signed-off-by: Dumitru Ceclan <dumitru.ceclan@analog.com>
>>>>> ---
>>>>>  drivers/iio/adc/ad7173.c | 71 ++++++++++++++++++++++++++++++++++--------------
>>>>>  1 file changed, 50 insertions(+), 21 deletions(-)
>>>>>
>>>>> diff --git a/drivers/iio/adc/ad7173.c b/drivers/iio/adc/ad7173.c
>>>>> index 6e249628bc64..a20831d99aa5 100644
>>>>> --- a/drivers/iio/adc/ad7173.c
>>>>> +++ b/drivers/iio/adc/ad7173.c
>>>>> @@ -60,6 +60,7 @@
>>>>>  #define AD7173_CH_SETUP_AINPOS_MASK	GENMASK(9, 5)
>>>>>  #define AD7173_CH_SETUP_AINNEG_MASK	GENMASK(4, 0)
>>>>>  
>>>>> +#define AD7173_NO_AINS_PER_CHANNEL	2
>>>>>  #define AD7173_CH_ADDRESS(pos, neg) \
>>>>>  	(FIELD_PREP(AD7173_CH_SETUP_AINPOS_MASK, pos) | \
>>>>>  	 FIELD_PREP(AD7173_CH_SETUP_AINNEG_MASK, neg))
>>>>> @@ -623,6 +624,7 @@ static int ad7173_setup(struct iio_dev *indio_dev)
>>>>>  static unsigned int ad7173_get_ref_voltage_milli(struct ad7173_state *st,
>>>>>  						 u8 reference_select)
>>>>>  {
>>>>> +	struct device *dev = &st->sd.spi->dev;
>>>>>  	int vref;
>>>>>  
>>>>>  	switch (reference_select) {
>>>>> @@ -646,9 +648,11 @@ static unsigned int ad7173_get_ref_voltage_milli(struct
>>>>> ad7173_state *st,
>>>>>  		return -EINVAL;
>>>>>  	}
>>>>>  
>>>>> -	if (vref < 0)
>>>>> +	if (vref < 0) {
>>>>> +		dev_err(dev, "Cannot use reference %u. Error:%d\n",
>>>>> +			reference_select, vref);
>>>>>  		return vref;
>>>>> -
>>>>> +	}
>>>>>  	return vref / (MICRO / MILLI);
>>>>>  }
>>>>>  
>>>>> @@ -905,13 +909,50 @@ static int ad7173_register_clk_provider(struct iio_dev
>>>>> *indio_dev)
>>>>>  					   &st->int_clk_hw);
>>>>>  }
>>>>>  
>>>>> +static int ad7173_validate_voltage_ain_inputs(struct ad7173_state *st,
>>>>> +					      const unsigned int
>>>>> ain[AD7173_NO_AINS_PER_CHANNEL])
>>>> I was late to the game in replying to previous thread.
>>>>
>>>> This is neater without the loop and with 2 parameters.  Anyhow see reply to v3.
>>>>
>>>
>>> Yeps, even more given that we're passing/copying the complete array which always
>>> fells awkward to me :)
>>>
>>> - Nuno Sá
>>>
>>>
>>
>> I rewrote the function, but it feels a bit awkward, perhaps I could get a bit of
>> advice before sending V5:
> 
> Maybe we could make this easier to read with macros?
> 
>>
>> static int ad7173_validate_voltage_ain_inputs(struct ad7173_state *st,
>> 					      unsigned int ain0, unsigned int ain1)
>> {
>> 	struct device *dev = &st->sd.spi->dev;
>> 	bool special_input0, special_input1;
>>
>> 	special_input0 = ain0 == AD7173_AIN_REF_POS || ain0 == AD7173_AIN_REF_NEG ||
>> 			 ((ain0 == AD7173_AIN_COM_IN_POS || ain0 == AD7173_AIN_COM_IN_NEG) &&
>> 			 (st->info->has_common_input)) || ain0 == AD4111_VINCOM_INPUT;
>> 	special_input1 = (ain1 == AD7173_AIN_REF_POS || ain1 == AD7173_AIN_REF_NEG) ||
>> 			 ((ain1 == AD7173_AIN_COM_IN_POS || ain1 == AD7173_AIN_COM_IN_NEG) &&
>> 			 (st->info->has_common_input)) || ain1 == AD4111_VINCOM_INPUT;
>>
> 
> 	special_input0 = AD7173_IS_SPECIAL_INPUT(ain0);
> 	special_input1 = AD7173_IS_SPECIAL_INPUT(ain1);
> 
>> 	if (st->info->has_vincom_input) {
>> 		if (ain0 == AD4111_VINCOM_INPUT &&
>> 		    ain1 < st->info->num_voltage_in && /* Normal input */
>> 		    ain1 >= st->info->num_voltage_in_div) /* Input without divider */
>> 			return dev_err_probe(dev, -EINVAL,
>> 				"VINCOM must be paired with inputs having divider.\n");
>>
>> 		if (ain1 == AD4111_VINCOM_INPUT &&
>> 		    ain0 < st->info->num_voltage_in && /* Normal input */
>> 		    ain0 >= st->info->num_voltage_in_div) /* Input without divider */
>> 			return dev_err_probe(dev, -EINVAL,
>> 				"VINCOM must be paired with inputs having divider.\n");
> 
> 		if (AD7173_IS_VINCOM_MISMATCH(ain0, ain1) ||
> 		    AD7173_IS_VINCOM_MISMATCH(ain1, ain0)) {
>  			return dev_err_probe(dev, -EINVAL,
>  				"VINCOM must be paired with inputs having divider.\n");
> 
>> 	}
>>
>> 	if ((ain0 >= st->info->num_voltage_in && !special_input0) ||
>> 	    (ain1 >= st->info->num_voltage_in && !special_input1))
>> 		return dev_err_probe(dev, -EINVAL,
>> 				     "Input pin number out of range for pair (%d %d).\n",
>> 				     ain0, ain1);
>>
>> 	if (!special_input0 && !special_input1 &&
>> 	    ((ain0 >= st->info->num_voltage_in_div) !=
>> 	     (ain1 >= st->info->num_voltage_in_div)))
>> 		return dev_err_probe(dev, -EINVAL,
>> 			"Both inputs must either have a voltage divider or not have: (%d %d).\n",
>> 			ain0, ain1);
> 
> These last two don't seem so bad.
> 
>>

Thanks for the quick review :)