From 144345a4a8c3b497a3f60d3af9d6071a37660186 Mon Sep 17 00:00:00 2001
From: Geert Uytterhoeven <geert@linux-m68k.org>
Date: Sun, 8 Apr 2018 11:05:15 +0200
Subject: [PATCH] soc: bcm2835: Make !RASPBERRYPI_FIRMWARE dummies return failure
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Git-commit: 144345a4a8c3b497a3f60d3af9d6071a37660186
Patch-mainline: v4.17-rc3
References: bsc#1051510

If CONFIG_RASPBERRYPI_FIRMWARE=n:

    drivers/gpio/gpio-raspberrypi-exp.c: In function ‘rpi_exp_gpio_get_polarity’:
    drivers/gpio/gpio-raspberrypi-exp.c:71: warning: ‘get.polarity’ is used uninitialized in this function
    drivers/gpio/gpio-raspberrypi-exp.c: In function ‘rpi_exp_gpio_get_direction’:
    drivers/gpio/gpio-raspberrypi-exp.c:150: warning: ‘get.direction’ is used uninitialized in this function

The dummy firmware interface functions return 0, which means success,
causing subsequent code to make use of the never initialized output
parameter.

Fix this by making the dummy functions return an error code (-ENOSYS)
instead.

Note that this assumes the firmware always fills in the requested data
in the CONFIG_RASPBERRYPI_FIRMWARE=y case.

Fixes: d45f1a563b92dac7 ("staging: vc04_services: fix up rpi firmware functions")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 include/soc/bcm2835/raspberrypi-firmware.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/soc/bcm2835/raspberrypi-firmware.h b/include/soc/bcm2835/raspberrypi-firmware.h
index 50df5b28d2c9..8ee8991aa099 100644
--- a/include/soc/bcm2835/raspberrypi-firmware.h
+++ b/include/soc/bcm2835/raspberrypi-firmware.h
@@ -143,13 +143,13 @@ struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node);
 static inline int rpi_firmware_property(struct rpi_firmware *fw, u32 tag,
 					void *data, size_t len)
 {
-	return 0;
+	return -ENOSYS;
 }
 
 static inline int rpi_firmware_property_list(struct rpi_firmware *fw,
 					     void *data, size_t tag_size)
 {
-	return 0;
+	return -ENOSYS;
 }
 
 static inline struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node)
-- 
2.18.0