iio: proximity: isl29501: Fix return type of isl29501_register_writegrafted

isl29501_register_write() was returning a u32 instead of an int.
Since the function returns negative error codes (such as -ERANGE or
return values from i2c_smbus_write_byte_data()), returning an unsigned
integer type prevents callers from correctly checking for negative error
conditions.

Fix this by changing the function return type from u32 to int.

This was found through manual code review.

Fixes: 1c28799257bc ("iio: light: isl29501: Add support for the ISL29501 ToF sensor.")
Signed-off-by: Salah Triki <salah.triki@gmail.com>
Reviewed-by: Joshua Crofts <joshua.crofts1@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Jonathan Cameron <jonathan.cameron@oss.qualcomm.com>

1 files changed, 51 insertions, 0 deletions

diff --git a/include/drm/intel/pick.h b/include/drm/intel/pick.h
new file mode 100644
index 000000000..d976fab8f
--- /dev/null
+++ b/include/drm/intel/pick.h
@@ -0,0 +1,51 @@
+/* SPDX-License-Identifier: MIT */
+/* Copyright © 2026 Intel Corporation */
+
+#ifndef _PICK_H_
+#define _PICK_H_
+
+/*
+ * Given the first two numbers __a and __b of arbitrarily many evenly spaced
+ * numbers, pick the 0-based __index'th value.
+ *
+ * Always prefer this over _PICK() if the numbers are evenly spaced.
+ */
+#define _PICK_EVEN(__index, __a, __b) ((__a) + (__index) * ((__b) - (__a)))
+
+/*
+ * Like _PICK_EVEN(), but supports 2 ranges of evenly spaced address offsets.
+ * @__c_index corresponds to the index in which the second range starts to be
+ * used. Using math interval notation, the first range is used for indexes [ 0,
+ * @__c_index), while the second range is used for [ @__c_index, ... ). Example:
+ *
+ * #define _FOO_A			0xf000
+ * #define _FOO_B			0xf004
+ * #define _FOO_C			0xf008
+ * #define _SUPER_FOO_A			0xa000
+ * #define _SUPER_FOO_B			0xa100
+ * #define FOO(x)			_MMIO(_PICK_EVEN_2RANGES(x, 3,		\
+ *					      _FOO_A, _FOO_B,			\
+ *					      _SUPER_FOO_A, _SUPER_FOO_B))
+ *
+ * This expands to:
+ *	0: 0xf000,
+ *	1: 0xf004,
+ *	2: 0xf008,
+ *	3: 0xa000,
+ *	4: 0xa100,
+ *	5: 0xa200,
+ *	...
+ */
+#define _PICK_EVEN_2RANGES(__index, __c_index, __a, __b, __c, __d)		\
+	(BUILD_BUG_ON_ZERO(!__is_constexpr(__c_index)) +			\
+	 ((__index) < (__c_index) ? _PICK_EVEN(__index, __a, __b) :		\
+				   _PICK_EVEN((__index) - (__c_index), __c, __d)))
+
+/*
+ * Given the arbitrary numbers in varargs, pick the 0-based __index'th number.
+ *
+ * Always prefer _PICK_EVEN() over this if the numbers are evenly spaced.
+ */
+#define _PICK(__index, ...) (((const u32 []){ __VA_ARGS__ })[__index])
+
+#endif