From 409a51e0a4a5f908763191fae2c29008632eb712 Mon Sep 17 00:00:00 2001
From: Sergey Larin <cerg2010cerg2010@mail.ru>
Date: Sat, 2 Mar 2019 19:54:55 +0300
Subject: [PATCH] iio: gyro: mpu3050: fix chip ID reading
Git-commit: 409a51e0a4a5f908763191fae2c29008632eb712
Patch-mainline: v5.1-rc6
References: bsc#1051510

According to the datasheet, the last bit of CHIP_ID register controls
I2C bus, and the first one is unused. Handle this correctly.

Note that there are chips out there that have a value such that
the id check currently fails.

Signed-off-by: Sergey Larin <cerg2010cerg2010@mail.ru>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/iio/gyro/mpu3050-core.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/iio/gyro/mpu3050-core.c b/drivers/iio/gyro/mpu3050-core.c
index 77fac81a3adc..5ddebede31a6 100644
--- a/drivers/iio/gyro/mpu3050-core.c
+++ b/drivers/iio/gyro/mpu3050-core.c
@@ -29,7 +29,8 @@
 
 #include "mpu3050.h"
 
-#define MPU3050_CHIP_ID		0x69
+#define MPU3050_CHIP_ID		0x68
+#define MPU3050_CHIP_ID_MASK	0x7E
 
 /*
  * Register map: anything suffixed *_H is a big-endian high byte and always
@@ -1176,8 +1177,9 @@ int mpu3050_common_probe(struct device *dev,
 		goto err_power_down;
 	}
 
-	if (val != MPU3050_CHIP_ID) {
-		dev_err(dev, "unsupported chip id %02x\n", (u8)val);
+	if ((val & MPU3050_CHIP_ID_MASK) != MPU3050_CHIP_ID) {
+		dev_err(dev, "unsupported chip id %02x\n",
+				(u8)(val & MPU3050_CHIP_ID_MASK));
 		ret = -ENODEV;
 		goto err_power_down;
 	}
-- 
2.16.4