linux-kernel - Re: [PATCH 06/11] staging: iio: adc: ad7606: Use find

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Message-ID: <20181216135136.7c7bde18@archlinux>
Date:   Sun, 16 Dec 2018 13:51:36 +0000
From:   Jonathan Cameron <jic23@...nel.org>
To:     Stefan Popa <stefan.popa@...log.com>
Cc:     <robh+dt@...nel.org>, <mark.rutland@....com>,
        <Michael.Hennerich@...log.com>, <knaack.h@....de>,
        <lars@...afoo.de>, <pmeerw@...erw.net>,
        <gregkh@...uxfoundation.org>, <linux-kernel@...r.kernel.org>,
        <linux-iio@...r.kernel.org>, <devel@...verdev.osuosl.org>,
        <stefan.popa@...log.co>
Subject: Re: [PATCH 06/11] staging: iio: adc: ad7606: Use find_closest()
 macro

On Thu, 13 Dec 2018 14:46:18 +0200
Stefan Popa <stefan.popa@...log.com> wrote:

> When looking for the available scale or oversampling ratio, it is better
> to use the find_closest() macro. This simplifies the code and also does
> not require an exact value to be entered from the user space.
> 
> Signed-off-by: Stefan Popa <stefan.popa@...log.com>
Nice little cleanup.

Applied to the togreg branch of iio.git and pushed out as testing for
the autobuilders to play with it.

Thanks,

Jonathan

> ---
>  drivers/staging/iio/adc/ad7606.c | 58 +++++++++++++++-------------------------
>  1 file changed, 22 insertions(+), 36 deletions(-)
> 
> diff --git a/drivers/staging/iio/adc/ad7606.c b/drivers/staging/iio/adc/ad7606.c
> index 13aeeec..0925379 100644
> --- a/drivers/staging/iio/adc/ad7606.c
> +++ b/drivers/staging/iio/adc/ad7606.c
> @@ -16,6 +16,7 @@
>  #include <linux/delay.h>
>  #include <linux/sched.h>
>  #include <linux/module.h>
> +#include <linux/util_macros.h>
>  
>  #include <linux/iio/iio.h>
>  #include <linux/iio/sysfs.h>
> @@ -30,8 +31,12 @@
>   * Scales are computed as 5000/32768 and 10000/32768 respectively,
>   * so that when applied to the raw values they provide mV values
>   */
> -static const unsigned int scale_avail[2][2] = {
> -	{0, 152588}, {0, 305176}
> +static const unsigned int scale_avail[2] = {
> +	152588, 305176
> +};
> +
> +static const unsigned int ad7606_oversampling_avail[7] = {
> +	1, 2, 4, 8, 16, 32, 64,
>  };
>  
>  static int ad7606_reset(struct ad7606_state *st)
> @@ -148,8 +153,8 @@ static int ad7606_read_raw(struct iio_dev *indio_dev,
>  		*val = (short)ret;
>  		return IIO_VAL_INT;
>  	case IIO_CHAN_INFO_SCALE:
> -		*val = scale_avail[st->range][0];
> -		*val2 = scale_avail[st->range][1];
> +		*val = 0;
> +		*val2 = scale_avail[st->range];
>  		return IIO_VAL_INT_PLUS_MICRO;
>  	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
>  		*val = st->oversampling;
> @@ -165,8 +170,8 @@ static ssize_t in_voltage_scale_available_show(struct device *dev,
>  	int i, len = 0;
>  
>  	for (i = 0; i < ARRAY_SIZE(scale_avail); i++)
> -		len += scnprintf(buf + len, PAGE_SIZE - len, "%d.%06u ",
> -				 scale_avail[i][0], scale_avail[i][1]);
> +		len += scnprintf(buf + len, PAGE_SIZE - len, "0.%06u ",
> +				 scale_avail[i]);
>  
>  	buf[len - 1] = '\n';
>  
> @@ -175,18 +180,6 @@ static ssize_t in_voltage_scale_available_show(struct device *dev,
>  
>  static IIO_DEVICE_ATTR_RO(in_voltage_scale_available, 0);
>  
> -static int ad7606_oversampling_get_index(unsigned int val)
> -{
> -	unsigned char supported[] = {1, 2, 4, 8, 16, 32, 64};
> -	int i;
> -
> -	for (i = 0; i < ARRAY_SIZE(supported); i++)
> -		if (val == supported[i])
> -			return i;
> -
> -	return -EINVAL;
> -}
> -
>  static int ad7606_write_raw(struct iio_dev *indio_dev,
>  			    struct iio_chan_spec const *chan,
>  			    int val,
> @@ -195,36 +188,29 @@ static int ad7606_write_raw(struct iio_dev *indio_dev,
>  {
>  	struct ad7606_state *st = iio_priv(indio_dev);
>  	DECLARE_BITMAP(values, 3);
> -	int ret, i;
> +	int i;
>  
>  	switch (mask) {
>  	case IIO_CHAN_INFO_SCALE:
> -		ret = -EINVAL;
>  		mutex_lock(&st->lock);
> -		for (i = 0; i < ARRAY_SIZE(scale_avail); i++)
> -			if (val2 == scale_avail[i][1]) {
> -				gpiod_set_value(st->gpio_range, i);
> -				st->range = i;
> -
> -				ret = 0;
> -				break;
> -			}
> +		i = find_closest(val2, scale_avail, ARRAY_SIZE(scale_avail));
> +		gpiod_set_value(st->gpio_range, i);
> +		st->range = i;
>  		mutex_unlock(&st->lock);
>  
> -		return ret;
> +		return 0;
>  	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
>  		if (val2)
>  			return -EINVAL;
> -		ret = ad7606_oversampling_get_index(val);
> -		if (ret < 0)
> -			return ret;
> +		i = find_closest(val, ad7606_oversampling_avail,
> +				 ARRAY_SIZE(ad7606_oversampling_avail));
>  
> -		values[0] = ret;
> +		values[0] = i;
>  
>  		mutex_lock(&st->lock);
> -		gpiod_set_array_value(3, st->gpio_os->desc, st->gpio_os->info,
> -				      values);
> -		st->oversampling = val;
> +		gpiod_set_array_value(ARRAY_SIZE(values), st->gpio_os->desc,
> +				      st->gpio_os->info, values);
> +		st->oversampling = ad7606_oversampling_avail[i];
>  		mutex_unlock(&st->lock);
>  
>  		return 0;