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Date: Tue, 19 Sep 2023 13:24:46 +0100
From: Jonathan Cameron <Jonathan.Cameron@...wei.com>
To: <alisadariana@...il.com>
CC: Alisa-Dariana Roman <alisa.roman@...log.com>,
Lars-Peter Clausen <lars@...afoo.de>,
Michael Hennerich <Michael.Hennerich@...log.com>,
Alexandru Tachici <alexandru.tachici@...log.com>,
Jonathan Cameron <jic23@...nel.org>,
<linux-iio@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/3] iio: adc: ad7192: Use bitfield access macros
On Tue, 19 Sep 2023 00:48:52 +0300
alisadariana@...il.com wrote:
> From: Alisa-Dariana Roman <alisadariana@...il.com>
>
> Include bitfield.h and update driver to use bitfield access macros
> GENMASK, FIELD_PREP and FIELD_GET.
>
> Also simplify AD7192_CONF_GAIN(-1) to AD7192_CONF_GAIN_MASK and
> AD7192_MODE_RATE(-1) to AD7192_MODE_RATE_MASK.
>
> Signed-off-by: Alisa-Dariana Roman <alisa.roman@...log.com>
> ---
> drivers/iio/adc/ad7192.c | 50 +++++++++++++++++++++++++---------------
> 1 file changed, 32 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/iio/adc/ad7192.c b/drivers/iio/adc/ad7192.c
> index 69d1103b9508..e83fecb63c1d 100644
> --- a/drivers/iio/adc/ad7192.c
> +++ b/drivers/iio/adc/ad7192.c
> @@ -6,6 +6,7 @@
> */
>
> #include <linux/interrupt.h>
> +#include <linux/bitfield.h>
> #include <linux/clk.h>
> #include <linux/device.h>
> #include <linux/kernel.h>
> @@ -43,7 +44,9 @@
> #define AD7192_COMM_WEN BIT(7) /* Write Enable */
> #define AD7192_COMM_WRITE 0 /* Write Operation */
> #define AD7192_COMM_READ BIT(6) /* Read Operation */
> -#define AD7192_COMM_ADDR(x) (((x) & 0x7) << 3) /* Register Address */
> +#define AD7192_COMM_ADDR_MASK GENMASK(5, 3) /* Register Address Mask */
> +#define AD7192_COMM_ADDR(x) FIELD_PREP(AD7192_COMM_ADDR_MASK, x)
> + /* Register Address */
> #define AD7192_COMM_CREAD BIT(2) /* Continuous Read of Data Register */
>
> /* Status Register Bit Designations (AD7192_REG_STAT) */
> @@ -56,17 +59,24 @@
> #define AD7192_STAT_CH1 BIT(0) /* Channel 1 */
>
> /* Mode Register Bit Designations (AD7192_REG_MODE) */
> -#define AD7192_MODE_SEL(x) (((x) & 0x7) << 21) /* Operation Mode Select */
> -#define AD7192_MODE_SEL_MASK (0x7 << 21) /* Operation Mode Select Mask */
> -#define AD7192_MODE_STA(x) (((x) & 0x1) << 20) /* Status Register transmission */
> +#define AD7192_MODE_SEL_MASK GENMASK(23, 21) /* Operation Mode Select Mask */
> +#define AD7192_MODE_SEL(x) FIELD_PREP(AD7192_MODE_SEL_MASK, x)
Hi Alisa-Dariana,
Whilst it is a bigger change, I'd ideally like all these XXX(x) calls to be replaced
inline with the FIELD_PREP(). It is just as clear to read and in many cases better
because you get patterns that go form
st->mode &= ~AD7192_MODE_SEL_MASK;
st->mode |= AD7192_MODE_SEL(mode);
which becomes the more visible and obvious
st->mode &= ~AD7192_MODE_SEL_MASK;
st->mode |= FIELD_PREP(AD7192_MODE_SEL_MASK, mode);
where you can clearly see the same bits were removed from st->mode, then
filled in with the new field value.
That's obscured with the additional macro.
Jonathan
> + /* Operation Mode Select */
> #define AD7192_MODE_STA_MASK BIT(20) /* Status Register transmission Mask */
> -#define AD7192_MODE_CLKSRC(x) (((x) & 0x3) << 18) /* Clock Source Select */
> +#define AD7192_MODE_STA(x) FIELD_PREP(AD7192_MODE_STA_MASK, x)
> + /* Status Register transmission */
> +#define AD7192_MODE_CLKSRC_MASK GENMASK(19, 18) /* Clock Source Select Mask */
> +#define AD7192_MODE_CLKSRC(x) FIELD_PREP(AD7192_MODE_CLKSRC_MASK, x)
> + /* Clock Source Select */
> #define AD7192_MODE_SINC3 BIT(15) /* SINC3 Filter Select */
> #define AD7192_MODE_ENPAR BIT(13) /* Parity Enable */
> #define AD7192_MODE_CLKDIV BIT(12) /* Clock divide by 2 (AD7190/2 only)*/
> #define AD7192_MODE_SCYCLE BIT(11) /* Single cycle conversion */
> #define AD7192_MODE_REJ60 BIT(10) /* 50/60Hz notch filter */
> -#define AD7192_MODE_RATE(x) ((x) & 0x3FF) /* Filter Update Rate Select */
> +#define AD7192_MODE_RATE_MASK GENMASK(9, 0)
> + /* Filter Update Rate Select Mask */
> +#define AD7192_MODE_RATE(x) FIELD_PREP(AD7192_MODE_RATE_MASK, x)
> + /* Filter Update Rate Select */
>
> /* Mode Register: AD7192_MODE_SEL options */
> #define AD7192_MODE_CONT 0 /* Continuous Conversion Mode */
> @@ -92,13 +102,16 @@
> #define AD7192_CONF_CHOP BIT(23) /* CHOP enable */
> #define AD7192_CONF_ACX BIT(22) /* AC excitation enable(AD7195 only) */
> #define AD7192_CONF_REFSEL BIT(20) /* REFIN1/REFIN2 Reference Select */
> -#define AD7192_CONF_CHAN(x) ((x) << 8) /* Channel select */
> -#define AD7192_CONF_CHAN_MASK (0x7FF << 8) /* Channel select mask */
> +#define AD7192_CONF_CHAN_MASK GENMASK(18, 8) /* Channel select mask */
> +#define AD7192_CONF_CHAN(x) FIELD_PREP(AD7192_CONF_CHAN_MASK, x)
> + /* Channel select */
> #define AD7192_CONF_BURN BIT(7) /* Burnout current enable */
> #define AD7192_CONF_REFDET BIT(6) /* Reference detect enable */
> #define AD7192_CONF_BUF BIT(4) /* Buffered Mode Enable */
> #define AD7192_CONF_UNIPOLAR BIT(3) /* Unipolar/Bipolar Enable */
> -#define AD7192_CONF_GAIN(x) ((x) & 0x7) /* Gain Select */
> +#define AD7192_CONF_GAIN_MASK GENMASK(2, 0) /* Gain Select */
> +#define AD7192_CONF_GAIN(x) FIELD_PREP(AD7192_CONF_GAIN_MASK, x)
> + /* Gain Select */
>
> #define AD7192_CH_AIN1P_AIN2M BIT(0) /* AIN1(+) - AIN2(-) */
> #define AD7192_CH_AIN3P_AIN4M BIT(1) /* AIN3(+) - AIN4(-) */
> @@ -130,7 +143,7 @@
> #define CHIPID_AD7192 0x0
> #define CHIPID_AD7193 0x2
> #define CHIPID_AD7195 0x6
> -#define AD7192_ID_MASK 0x0F
> +#define AD7192_ID_MASK GENMASK(3, 0)
>
> /* GPOCON Register Bit Designations (AD7192_REG_GPOCON) */
> #define AD7192_GPOCON_BPDSW BIT(6) /* Bridge power-down switch enable */
> @@ -399,7 +412,7 @@ static int ad7192_setup(struct iio_dev *indio_dev, struct device_node *np)
> if (ret)
> return ret;
>
> - id &= AD7192_ID_MASK;
> + id = FIELD_GET(AD7192_ID_MASK, id);
>
> if (id != st->chip_info->chip_id)
> dev_warn(&st->sd.spi->dev, "device ID query failed (0x%X != 0x%X)\n",
> @@ -472,7 +485,7 @@ static ssize_t ad7192_show_ac_excitation(struct device *dev,
> struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> struct ad7192_state *st = iio_priv(indio_dev);
>
> - return sysfs_emit(buf, "%d\n", !!(st->conf & AD7192_CONF_ACX));
> + return sysfs_emit(buf, "%d\n", !!FIELD_GET(AD7192_CONF_ACX, st->conf));
> }
>
> static ssize_t ad7192_show_bridge_switch(struct device *dev,
> @@ -482,7 +495,8 @@ static ssize_t ad7192_show_bridge_switch(struct device *dev,
> struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> struct ad7192_state *st = iio_priv(indio_dev);
>
> - return sysfs_emit(buf, "%d\n", !!(st->gpocon & AD7192_GPOCON_BPDSW));
> + return sysfs_emit(buf, "%d\n",
> + !!FIELD_GET(AD7192_GPOCON_BPDSW, st->gpocon));
> }
>
> static ssize_t ad7192_set(struct device *dev,
> @@ -667,9 +681,9 @@ static int ad7192_get_3db_filter_freq(struct ad7192_state *st)
> fadc = DIV_ROUND_CLOSEST(st->fclk,
> st->f_order * AD7192_MODE_RATE(st->mode));
>
> - if (st->conf & AD7192_CONF_CHOP)
> + if (FIELD_GET(AD7192_CONF_CHOP, st->conf))
> return DIV_ROUND_CLOSEST(fadc * 240, 1024);
> - if (st->mode & AD7192_MODE_SINC3)
> + if (FIELD_GET(AD7192_MODE_SINC3, st->mode))
> return DIV_ROUND_CLOSEST(fadc * 272, 1024);
> else
> return DIV_ROUND_CLOSEST(fadc * 230, 1024);
> @@ -682,7 +696,7 @@ static int ad7192_read_raw(struct iio_dev *indio_dev,
> long m)
> {
> struct ad7192_state *st = iio_priv(indio_dev);
> - bool unipolar = !!(st->conf & AD7192_CONF_UNIPOLAR);
> + bool unipolar = !!FIELD_GET(AD7192_CONF_UNIPOLAR, st->conf);
>
> switch (m) {
> case IIO_CHAN_INFO_RAW:
> @@ -746,7 +760,7 @@ static int ad7192_write_raw(struct iio_dev *indio_dev,
> if (val2 == st->scale_avail[i][1]) {
> ret = 0;
> tmp = st->conf;
> - st->conf &= ~AD7192_CONF_GAIN(-1);
> + st->conf &= ~AD7192_CONF_GAIN_MASK;
> st->conf |= AD7192_CONF_GAIN(i);
> if (tmp == st->conf)
> break;
> @@ -769,7 +783,7 @@ static int ad7192_write_raw(struct iio_dev *indio_dev,
> break;
> }
>
> - st->mode &= ~AD7192_MODE_RATE(-1);
> + st->mode &= ~AD7192_MODE_RATE_MASK;
> st->mode |= AD7192_MODE_RATE(div);
> ad_sd_write_reg(&st->sd, AD7192_REG_MODE, 3, st->mode);
> break;
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