--- /dev/null
+From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
+Date: Tue, 12 Dec 2023 18:23:45 +0100
+Subject: [PATCH] fw_env: fix reading NVMEM device's "compatible" value
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+Call to fread() was changed to check for return value. The problem is it
+can't be checked for returning 1 (as it is) to determine success.
+
+We call fread() with buffer size as "size" argument. Reading any
+"compatible" value shorter than buffer size will result in returning 0
+even on success.
+
+Modify code to use fstat() to determine expected read length.
+
+This fixes regression that broke using fw_env with NVMEM devices.
+
+Fixes: c059a22b7776 ("tools: env: fw_env: Fix unused-result warning")
+Cc: Jaehoon Chung <jh80.chung@samsung.com>
+Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
+---
+ tools/env/fw_env.c | 18 ++++++++++++++----
+ 1 file changed, 14 insertions(+), 4 deletions(-)
+
+--- a/tools/env/fw_env.c
++++ b/tools/env/fw_env.c
+@@ -1732,6 +1732,7 @@ static int find_nvmem_device(void)
+ }
+
+ while (!nvmem && (dent = readdir(dir))) {
++ struct stat s;
+ FILE *fp;
+ size_t size;
+
+@@ -1749,14 +1750,22 @@ static int find_nvmem_device(void)
+ continue;
+ }
+
+- size = fread(buf, sizeof(buf), 1, fp);
++ if (fstat(fileno(fp), &s)) {
++ fprintf(stderr, "Failed to fstat %s\n", comp);
++ goto next;
++ }
++
++ if (s.st_size >= sizeof(buf)) {
++ goto next;
++ }
++
++ size = fread(buf, s.st_size, 1, fp);
+ if (size != 1) {
+ fprintf(stderr,
+ "read failed about %s\n", comp);
+- fclose(fp);
+- return -EIO;
++ goto next;
+ }
+-
++ buf[s.st_size] = '\0';
+
+ if (!strcmp(buf, "u-boot,env")) {
+ bytes = asprintf(&nvmem, "%s/%s/nvmem", path, dent->d_name);
+@@ -1765,6 +1774,7 @@ static int find_nvmem_device(void)
+ }
+ }
+
++next:
+ fclose(fp);
+ }
+