Re: [PATCH v5 10/10] iio: adc: ti-ads1015: replace custom shift macros with FIELD_PREP/GET

[Andy Shevchenko]

On Wed, Sep 30, 2026 at 10:42:04PM +0530, Archit Anant wrote:
> The driver currently uses custom _SHIFT macros and manual bitwise
> operations to read and write to the configuration register.
> 
> Modernize the bitwise logic by replacing all manual shifts with the
> standard FIELD_PREP() and FIELD_GET() macros from <linux/bitfield.h>.
> This improves readability and prevents potential bitwise errors.
> 
> Remove the now-unused _SHIFT macros from the top of the file.

...

> int ads1015_get_adc_result(struct ads1015_data *data, int chan, int *val)

>  	dr = data->channel_data[chan].data_rate;
>  	mask = ADS1015_CFG_MUX_MASK | ADS1015_CFG_PGA_MASK |
>  		ADS1015_CFG_DR_MASK;
> -	cfg = chan << ADS1015_CFG_MUX_SHIFT | pga << ADS1015_CFG_PGA_SHIFT |
> -		dr << ADS1015_CFG_DR_SHIFT;
> +	cfg = FIELD_PREP(ADS1015_CFG_MUX_MASK, chan) |

> +	      FIELD_PREP(ADS1015_CFG_PGA_MASK, pga) |
> +	      FIELD_PREP(ADS1015_CFG_DR_MASK, dr);
>  
>  	if (ads1015_event_channel_enabled(data)) {
>  		mask |= ADS1015_CFG_COMP_QUE_MASK | ADS1015_CFG_COMP_MODE_MASK;
> -		cfg |= data->thresh_data[chan].comp_queue <<
> -				ADS1015_CFG_COMP_QUE_SHIFT |
> -			data->comp_mode <<
> -				ADS1015_CFG_COMP_MODE_SHIFT;
> +		cfg |= FIELD_PREP(ADS1015_CFG_COMP_QUE_MASK,
> +				  data->thresh_data[chan].comp_queue) |
> +		       FIELD_PREP(ADS1015_CFG_COMP_MODE_MASK,
> +				  data->comp_mode);
>  	}

Personally I would go with if-else with full initialisations of mask and cfg.

	if (ads1015_event_channel_enabled(data)) {
		mask = ADS1015_CFG_COMP_QUE_MASK | ADS1015_CFG_COMP_MODE_MASK |
		       ADS1015_CFG_MUX_MASK | ADS1015_CFG_PGA_MASK |
		       ADS1015_CFG_DR_MASK;
		cfg = FIELD_PREP(ADS1015_CFG_MUX_MASK, chan) |
		      FIELD_PREP(ADS1015_CFG_PGA_MASK, pga) |
		      FIELD_PREP(ADS1015_CFG_DR_MASK, dr) |
		      FIELD_PREP(ADS1015_CFG_COMP_QUE_MASK,
				  data->thresh_data[chan].comp_queue) |
		      FIELD_PREP(ADS1015_CFG_COMP_MODE_MASK,
				  data->comp_mode);
	} else {
		mask = ADS1015_CFG_MUX_MASK | ADS1015_CFG_PGA_MASK |
		       ADS1015_CFG_DR_MASK;
		cfg = FIELD_PREP(ADS1015_CFG_MUX_MASK, chan) |
		      FIELD_PREP(ADS1015_CFG_PGA_MASK, pga) |
		      FIELD_PREP(ADS1015_CFG_DR_MASK, dr);
	}

// also note the broken indentation

-- 
With Best Regards,
Andy Shevchenko