Re: [PATCH v4 3/9] staging: iio: ad7780: set pattern values and masks directly

From: Ardelean, Alexandru
Date: Fri Mar 01 2019 - 02:17:17 EST


On Thu, 2019-02-28 at 11:24 -0300, Renato Lui Geh wrote:
>
>
> The AD7780 driver contains status pattern bits designed for checking
> whether serial transfers have been correctly performed. Pattern macros
> were previously generated through bit fields. This patch sets good
> pattern values directly and masks through GENMASK.
>
> Signed-off-by: Renato Lui Geh <renatogeh@xxxxxxxxx>
> ---
> drivers/staging/iio/adc/ad7780.c | 20 +++++++++-----------
> 1 file changed, 9 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/staging/iio/adc/ad7780.c
> b/drivers/staging/iio/adc/ad7780.c
> index 7a68e90ddf14..56c49e28f432 100644
> --- a/drivers/staging/iio/adc/ad7780.c
> +++ b/drivers/staging/iio/adc/ad7780.c
> @@ -17,6 +17,7 @@
> #include <linux/sched.h>
> #include <linux/gpio/consumer.h>
> #include <linux/module.h>
> +#include <linux/bits.h>
>
> #include <linux/iio/iio.h>
> #include <linux/iio/sysfs.h>
> @@ -28,16 +29,13 @@
> #define AD7780_ID1 BIT(4)
> #define AD7780_ID0 BIT(3)
> #define AD7780_GAIN BIT(2)
> -#define AD7780_PAT1 BIT(1)
> -#define AD7780_PAT0 BIT(0)

I don't see a problem to leave the bitfields; they can be read & matched
easier with the datasheet.

>
> -#define AD7780_PATTERN (AD7780_PAT0)
> -#define AD7780_PATTERN_MASK (AD7780_PAT0 | AD7780_PAT1)
>
> -#define AD7170_PAT2 BIT(2)

> +#define AD7780_PATTERN_GOOD 1

It was also nice before that the PAT0..PAT2 bitfields were used to define a
good pattern, since it's easier to match with the datasheet.


> +#define AD7780_PATTERN_MASK GENMASK(1, 0)

I like the general usage of GENMASK, but I'm not sure in this case it's
worth doing. Maybe I missed a discussion somewhere, about doing this
change, but it is mostly a cosmetic without any functional change.


>
> -#define AD7170_PATTERN (AD7780_PAT0 | AD7170_PAT2)
> -#define AD7170_PATTERN_MASK (AD7780_PAT0 | AD7780_PAT1 | AD7170_PAT2)
> +#define AD7170_PATTERN_GOOD 5
> +#define AD7170_PATTERN_MASK GENMASK(2, 0)
>
> #define AD7780_GAIN_MIDPOINT 64
> #define AD7780_FILTER_MIDPOINT 13350
> @@ -209,25 +207,25 @@ static const struct ad_sigma_delta_info
> ad7780_sigma_delta_info = {
> static const struct ad7780_chip_info ad7780_chip_info_tbl[] = {
> [ID_AD7170] = {
> .channel = AD7170_CHANNEL(12, 24),
> - .pattern = AD7170_PATTERN,
> + .pattern = AD7170_PATTERN_GOOD,
> .pattern_mask = AD7170_PATTERN_MASK,
> .is_ad778x = false,
> },
> [ID_AD7171] = {
> .channel = AD7170_CHANNEL(16, 24),
> - .pattern = AD7170_PATTERN,
> + .pattern = AD7170_PATTERN_GOOD,
> .pattern_mask = AD7170_PATTERN_MASK,
> .is_ad778x = false,
> },
> [ID_AD7780] = {
> .channel = AD7780_CHANNEL(24, 32),
> - .pattern = AD7780_PATTERN,
> + .pattern = AD7780_PATTERN_GOOD,
> .pattern_mask = AD7780_PATTERN_MASK,
> .is_ad778x = true,
> },
> [ID_AD7781] = {
> .channel = AD7780_CHANNEL(20, 32),
> - .pattern = AD7780_PATTERN,
> + .pattern = AD7780_PATTERN_GOOD,
> .pattern_mask = AD7780_PATTERN_MASK,
> .is_ad778x = true,
> },
> --
> 2.21.0
>