soc: mediatek: pwrap: Zero initialize rdata in pwrap_init_cipher

BugLink: https://bugs.launchpad.net/bugs/1836666

[ Upstream commit 89e28da8 ]

When building with -Wsometimes-uninitialized, Clang warns:

drivers/soc/mediatek/mtk-pmic-wrap.c:1358:6: error: variable 'rdata' is
used uninitialized whenever '||' condition is true
[-Werror,-Wsometimes-uninitialized]

If pwrap_write returns non-zero, pwrap_read will not be called to
initialize rdata, meaning that we will use some random uninitialized
stack value in our print statement. Zero initialize rdata in case this
happens.

Link: https://github.com/ClangBuiltLinux/linux/issues/401Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

drivers/soc/mediatek/mtk-pmic-wrap.c

@@ -591,7 +591,7 @@ static bool pwrap_is_pmic_cipher_ready(struct pmic_wrapper *wrp)
 static int pwrap_init_cipher(struct pmic_wrapper *wrp)
 {
 	int ret;
-	u32 rdata;
+	u32 rdata = 0;
 
 	pwrap_writel(wrp, 0x1, PWRAP_CIPHER_SWRST);
 	pwrap_writel(wrp, 0x0, PWRAP_CIPHER_SWRST);