Re: [PATCH 07/13] iio: lm3533: Use sysfs_emit()

[Johan Hovold <johan@kernel.org>]

On Thu, Dec 16, 2021 at 07:52:11PM +0100, Lars-Peter Clausen wrote:
> sysfs_emit() is preferred over raw s*printf() for sysfs attributes since it
> knows about the sysfs buffer specifics and has some built-in checks for
> size and alignment.

I realise that the above is some copy-paste boiler plate, but none of it
is really relevant here when the driver uses the attribute buffer
directly with scnprintf() and a PAGE_SIZE argument.

This should probably be rephrased in terms of consistency and the
documentation now claiming that only sysfs_emit() should be used in
show() functions (e.g. to avoid problems in drivers that would have
failed to follow the previous instructions).

> Use sysfs_emit() to format the custom device attributes of the lm3533
> driver.
> 
> Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>

That said, the change itself is otherwise fine even I'm not sure it's
generally worth the churn to convert all existing show() functions:

Reviewed-by: Johan Hovold <johan@kernel.org>

> ---
>  drivers/iio/light/lm3533-als.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/iio/light/lm3533-als.c b/drivers/iio/light/lm3533-als.c
> index 8a621244dd01..827bc25269e9 100644
> --- a/drivers/iio/light/lm3533-als.c
> +++ b/drivers/iio/light/lm3533-als.c
> @@ -417,7 +417,7 @@ static ssize_t show_thresh_either_en(struct device *dev,
>  		enable = 0;
>  	}
>  
> -	return scnprintf(buf, PAGE_SIZE, "%u\n", enable);
> +	return sysfs_emit(buf, "%u\n", enable);
>  }
>  
>  static ssize_t store_thresh_either_en(struct device *dev,
> @@ -474,7 +474,7 @@ static ssize_t show_zone(struct device *dev,
>  	if (ret)
>  		return ret;
>  
> -	return scnprintf(buf, PAGE_SIZE, "%u\n", zone);
> +	return sysfs_emit(buf, "%u\n", zone);
>  }
>  
>  enum lm3533_als_attribute_type {
> @@ -530,7 +530,7 @@ static ssize_t show_als_attr(struct device *dev,
>  	if (ret)
>  		return ret;
>  
> -	return scnprintf(buf, PAGE_SIZE, "%u\n", val);
> +	return sysfs_emit(buf, "%u\n", val);
>  }
>  
>  static ssize_t store_als_attr(struct device *dev,

Johan