linux-kernel - Re: [PATCH v6] iio: frequency: ad9832: Use FIELD

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Message-ID: <Z_v93dtgks2CquIn@debian-BULLSEYE-live-builder-AMD64>
Date: Sun, 13 Apr 2025 15:09:33 -0300
From: Marcelo Schmitt <marcelo.schmitt1@...il.com>
To: Siddharth Menon <simeddon@...il.com>
Cc: linux-iio@...r.kernel.org, lars@...afoo.de,
	Michael.Hennerich@...log.com, jic23@...nel.org,
	gregkh@...uxfoundation.org, linux-kernel@...r.kernel.org,
	linux-staging@...ts.linux.dev
Subject: Re: [PATCH v6] iio: frequency: ad9832: Use FIELD_PREP macro to set
 bit fields

Hi Siddharth,

Your patch looks good to me and I keep the review tag offered on the other email.
One small thing I noticed right before closing the driver. See comments below.

On 04/13, Siddharth Menon wrote:
> Use bitfield and bitmask macros to clearly specify AD9832 SPI
> command fields to make register write code more readable.
> 
> Suggested-by: Marcelo Schmitt <marcelo.schmitt1@...il.com>
> Signed-off-by: Siddharth Menon <simeddon@...il.com>
> ---
...
> +
> +		st->data = cpu_to_be16(FIELD_PREP(AD9832_CMD_MSK, AD9832_CMD_SYNCSELSRC) |
>  					st->ctrl_ss);
I think st->ctrl_ss alignment with the preceding parenthesis could also have
been adjusted since the patch is updating the very same assignment.
		st->data = cpu_to_be16(FIELD_PREP(AD9832_CMD_MSK, AD9832_CMD_SYNCSELSRC) |
						  st->ctrl_ss);
There are some other places where similar change could be done but these are
probably not a reason for a v7.

>  		ret = spi_sync(st->spi, &st->msg);
>  		break;
...
> -		st->data = cpu_to_be16((AD9832_CMD_FPSELECT << CMD_SHIFT) |
> +		st->data = cpu_to_be16(FIELD_PREP(AD9832_CMD_MSK, AD9832_CMD_FPSELECT) |
>  					st->ctrl_fp);
This one would have become 
		st->data = cpu_to_be16(FIELD_PREP(AD9832_CMD_MSK, AD9832_CMD_FPSELECT) |
						  st->ctrl_fp);

>  		ret = spi_sync(st->spi, &st->msg);
>  		break;
...
> -		st->data = cpu_to_be16((AD9832_CMD_FPSELECT << CMD_SHIFT) |
> +		st->data = cpu_to_be16(FIELD_PREP(AD9832_CMD_MSK, AD9832_CMD_FPSELECT) |
>  					st->ctrl_fp);
Same here
>  		ret = spi_sync(st->spi, &st->msg);
>  		break;
...
>  
> -		st->data = cpu_to_be16((AD9832_CMD_SLEEPRESCLR << CMD_SHIFT) |
> +		st->data = cpu_to_be16(FIELD_PREP(AD9832_CMD_MSK, AD9832_CMD_SLEEPRESCLR) |
>  					st->ctrl_src);
ditto

>  		ret = spi_sync(st->spi, &st->msg);
>  		break;
> @@ -396,7 +400,7 @@ static int ad9832_probe(struct spi_device *spi)
>  	spi_message_add_tail(&st->phase_xfer[1], &st->phase_msg);
>  
>  	st->ctrl_src = AD9832_SLEEP | AD9832_RESET | AD9832_CLR;
> -	st->data = cpu_to_be16((AD9832_CMD_SLEEPRESCLR << CMD_SHIFT) |
> +	st->data = cpu_to_be16(FIELD_PREP(AD9832_CMD_MSK, AD9832_CMD_SLEEPRESCLR) |
>  					st->ctrl_src);
ditto

Regards,
Marcelo