linux-kernel - [PATCH v5 3/6] iio: addac: stx104: Use define rather than hardcoded limit for write val

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Message-Id: <4c9f4f1b4a270d133be70c82a091351b531b5e3e.1680790580.git.william.gray@linaro.org>
Date:   Thu,  6 Apr 2023 10:40:12 -0400
From:   William Breathitt Gray <william.gray@...aro.org>
To:     Jonathan Cameron <jic23@...nel.org>,
        Lars-Peter Clausen <lars@...afoo.de>
Cc:     linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        William Breathitt Gray <william.gray@...aro.org>
Subject: [PATCH v5 3/6] iio: addac: stx104: Use define rather than hardcoded limit for write val

The DAC register is 16 bits wide, so the value passed by write_raw()
should be checked against that limit. Rather than hardcoding the 16-bit
maximum value limit, use a define to improve readability and make the
intention of the code clearer. The explicit cast is also avoided by
instead explicitly checking for negative values.

Suggested-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Signed-off-by: William Breathitt Gray <william.gray@...aro.org>
---
 drivers/iio/addac/stx104.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/addac/stx104.c b/drivers/iio/addac/stx104.c
index 8730b79e921c..0ed5f71b18cb 100644
--- a/drivers/iio/addac/stx104.c
+++ b/drivers/iio/addac/stx104.c
@@ -13,6 +13,7 @@
 #include <linux/ioport.h>
 #include <linux/isa.h>
 #include <linux/kernel.h>
+#include <linux/limits.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/mutex.h>
@@ -181,8 +182,7 @@ static int stx104_write_raw(struct iio_dev *indio_dev,
 		return 0;
 	case IIO_CHAN_INFO_RAW:
 		if (chan->output) {
-			/* DAC can only accept up to a 16-bit value */
-			if ((unsigned int)val > 65535)
+			if (val < 0 || val > U16_MAX)
 				return -EINVAL;
 
 			mutex_lock(&priv->lock);
-- 
2.39.2