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, 159 insertions, 0 deletions

diff --git a/lib/crypto/blake2s.c b/lib/crypto/blake2s.c
new file mode 100644
index 000000000..71578a084
--- /dev/null
+++ b/lib/crypto/blake2s.c
@@ -0,0 +1,159 @@
+// SPDX-License-Identifier: GPL-2.0 OR MIT
+/*
+ * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ *
+ * This is an implementation of the BLAKE2s hash and PRF functions.
+ *
+ * Information: https://blake2.net/
+ *
+ */
+
+#include <crypto/blake2s.h>
+#include <linux/bug.h>
+#include <linux/export.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/unroll.h>
+#include <linux/types.h>
+
+static const u8 blake2s_sigma[10][16] = {
+	{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 },
+	{ 14, 10, 4, 8, 9, 15, 13, 6, 1, 12, 0, 2, 11, 7, 5, 3 },
+	{ 11, 8, 12, 0, 5, 2, 15, 13, 10, 14, 3, 6, 7, 1, 9, 4 },
+	{ 7, 9, 3, 1, 13, 12, 11, 14, 2, 6, 5, 10, 4, 0, 15, 8 },
+	{ 9, 0, 5, 7, 2, 4, 10, 15, 14, 1, 11, 12, 6, 8, 3, 13 },
+	{ 2, 12, 6, 10, 0, 11, 8, 3, 4, 13, 7, 5, 15, 14, 1, 9 },
+	{ 12, 5, 1, 15, 14, 13, 4, 10, 0, 7, 6, 3, 9, 2, 8, 11 },
+	{ 13, 11, 7, 14, 12, 1, 3, 9, 5, 0, 15, 4, 8, 6, 2, 10 },
+	{ 6, 15, 14, 9, 11, 3, 0, 8, 12, 2, 13, 7, 1, 4, 10, 5 },
+	{ 10, 2, 8, 4, 7, 6, 1, 5, 15, 11, 9, 14, 3, 12, 13, 0 },
+};
+
+static inline void blake2s_increment_counter(struct blake2s_ctx *ctx, u32 inc)
+{
+	ctx->t[0] += inc;
+	ctx->t[1] += (ctx->t[0] < inc);
+}
+
+static void __maybe_unused
+blake2s_compress_generic(struct blake2s_ctx *ctx,
+			 const u8 *data, size_t nblocks, u32 inc)
+{
+	u32 m[16];
+	u32 v[16];
+	int i;
+
+	WARN_ON(IS_ENABLED(DEBUG) &&
+		(nblocks > 1 && inc != BLAKE2S_BLOCK_SIZE));
+
+	while (nblocks > 0) {
+		blake2s_increment_counter(ctx, inc);
+		memcpy(m, data, BLAKE2S_BLOCK_SIZE);
+		le32_to_cpu_array(m, ARRAY_SIZE(m));
+		memcpy(v, ctx->h, 32);
+		v[ 8] = BLAKE2S_IV0;
+		v[ 9] = BLAKE2S_IV1;
+		v[10] = BLAKE2S_IV2;
+		v[11] = BLAKE2S_IV3;
+		v[12] = BLAKE2S_IV4 ^ ctx->t[0];
+		v[13] = BLAKE2S_IV5 ^ ctx->t[1];
+		v[14] = BLAKE2S_IV6 ^ ctx->f[0];
+		v[15] = BLAKE2S_IV7 ^ ctx->f[1];
+
+#define G(r, i, a, b, c, d) do { \
+	a += b + m[blake2s_sigma[r][2 * i + 0]]; \
+	d = ror32(d ^ a, 16); \
+	c += d; \
+	b = ror32(b ^ c, 12); \
+	a += b + m[blake2s_sigma[r][2 * i + 1]]; \
+	d = ror32(d ^ a, 8); \
+	c += d; \
+	b = ror32(b ^ c, 7); \
+} while (0)
+
+		/*
+		 * Unroll the rounds loop to enable constant-folding of the
+		 * blake2s_sigma values.
+		 */
+		unrolled_full
+		for (int r = 0; r < 10; r++) {
+			G(r, 0, v[0], v[4], v[8], v[12]);
+			G(r, 1, v[1], v[5], v[9], v[13]);
+			G(r, 2, v[2], v[6], v[10], v[14]);
+			G(r, 3, v[3], v[7], v[11], v[15]);
+			G(r, 4, v[0], v[5], v[10], v[15]);
+			G(r, 5, v[1], v[6], v[11], v[12]);
+			G(r, 6, v[2], v[7], v[8], v[13]);
+			G(r, 7, v[3], v[4], v[9], v[14]);
+		}
+#undef G
+
+		for (i = 0; i < 8; ++i)
+			ctx->h[i] ^= v[i] ^ v[i + 8];
+
+		data += BLAKE2S_BLOCK_SIZE;
+		--nblocks;
+	}
+}
+
+#ifdef CONFIG_CRYPTO_LIB_BLAKE2S_ARCH
+#include "blake2s.h" /* $(SRCARCH)/blake2s.h */
+#else
+#define blake2s_compress blake2s_compress_generic
+#endif
+
+static inline void blake2s_set_lastblock(struct blake2s_ctx *ctx)
+{
+	ctx->f[0] = -1;
+}
+
+void blake2s_update(struct blake2s_ctx *ctx, const u8 *in, size_t inlen)
+{
+	const size_t fill = BLAKE2S_BLOCK_SIZE - ctx->buflen;
+
+	if (unlikely(!inlen))
+		return;
+	if (inlen > fill) {
+		memcpy(ctx->buf + ctx->buflen, in, fill);
+		blake2s_compress(ctx, ctx->buf, 1, BLAKE2S_BLOCK_SIZE);
+		ctx->buflen = 0;
+		in += fill;
+		inlen -= fill;
+	}
+	if (inlen > BLAKE2S_BLOCK_SIZE) {
+		const size_t nblocks = DIV_ROUND_UP(inlen, BLAKE2S_BLOCK_SIZE);
+
+		blake2s_compress(ctx, in, nblocks - 1, BLAKE2S_BLOCK_SIZE);
+		in += BLAKE2S_BLOCK_SIZE * (nblocks - 1);
+		inlen -= BLAKE2S_BLOCK_SIZE * (nblocks - 1);
+	}
+	memcpy(ctx->buf + ctx->buflen, in, inlen);
+	ctx->buflen += inlen;
+}
+EXPORT_SYMBOL(blake2s_update);
+
+void blake2s_final(struct blake2s_ctx *ctx, u8 *out)
+{
+	WARN_ON(IS_ENABLED(DEBUG) && !out);
+	blake2s_set_lastblock(ctx);
+	memset(ctx->buf + ctx->buflen, 0,
+	       BLAKE2S_BLOCK_SIZE - ctx->buflen); /* Padding */
+	blake2s_compress(ctx, ctx->buf, 1, ctx->buflen);
+	cpu_to_le32_array(ctx->h, ARRAY_SIZE(ctx->h));
+	memcpy(out, ctx->h, ctx->outlen);
+	memzero_explicit(ctx, sizeof(*ctx));
+}
+EXPORT_SYMBOL(blake2s_final);
+
+#ifdef blake2s_mod_init_arch
+static int __init blake2s_mod_init(void)
+{
+	blake2s_mod_init_arch();
+	return 0;
+}
+subsys_initcall(blake2s_mod_init);
+#endif
+
+MODULE_DESCRIPTION("BLAKE2s hash function");
+MODULE_AUTHOR("Jason A. Donenfeld <Jason@zx2c4.com>");