linux-kernel - [PATCH] media: ov9650: avoid maybe-uninitialized warnings

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Date:   Wed, 26 Sep 2018 14:51:01 +0200
From:   Arnd Bergmann <arnd@...db.de>
To:     Sakari Ailus <sakari.ailus@...ux.intel.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>
Cc:     Arnd Bergmann <arnd@...db.de>,
        Akinobu Mita <akinobu.mita@...il.com>,
        Sylwester Nawrocki <s.nawrocki@...sung.com>,
        Hans Verkuil <hans.verkuil@...co.com>,
        Wolfram Sang <wsa+renesas@...g-engineering.com>,
        "Gustavo A. R. Silva" <gustavo@...eddedor.com>,
        linux-media@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] media: ov9650: avoid maybe-uninitialized warnings

The regmap change causes multiple warnings like

drivers/media/i2c/ov9650.c: In function 'ov965x_g_volatile_ctrl':
drivers/media/i2c/ov9650.c:889:29: error: 'reg2' may be used uninitialized in this function [-Werror=maybe-uninitialized]
   exposure = ((reg2 & 0x3f) << 10) | (reg1 << 2) |
              ~~~~~~~~~~~~~~~^~~~~~

It is apparently hard for the compiler to see here if ov965x_read()
returned successfully or not. Besides, we have a v4l2_dbg() statement
that prints an uninitialized value if regmap_read() fails.

Adding an 'else' clause avoids the ambiguity.

Fixes: 361f3803adfe ("media: ov9650: use SCCB regmap")
Signed-off-by: Arnd Bergmann <arnd@...db.de>
---
 drivers/media/i2c/ov9650.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/media/i2c/ov9650.c b/drivers/media/i2c/ov9650.c
index 3c9e6798d14b..77944da31de1 100644
--- a/drivers/media/i2c/ov9650.c
+++ b/drivers/media/i2c/ov9650.c
@@ -433,6 +433,8 @@ static int ov965x_read(struct ov965x *ov965x, u8 addr, u8 *val)
 	ret = regmap_read(ov965x->regmap, addr, &buf);
 	if (!ret)
 		*val = buf;
+        else
+                *val = -1;
 
 	v4l2_dbg(2, debug, &ov965x->sd, "%s: 0x%02x @ 0x%02x. (%d)\n",
 		 __func__, *val, addr, ret);
-- 
2.18.0