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authorHans de Goede <hdegoede@redhat.com>2016-09-11 18:29:16 +0200
committerJonathan Cameron <jic23@kernel.org>2016-09-12 20:19:16 +0100
commit1696566f995cfd4ddf3f167b4097cdc83f1458f2 (patch)
tree80389a4bf3ec17120542f7fa1cee3a9630d6c438 /drivers/iio
parent7ba4b884b7a890e240a13f5f65d607721e80396a (diff)
downloadlinux-1696566f995cfd4ddf3f167b4097cdc83f1458f2.tar.gz
iio: accel: mxc6255: Fix chip-id check
The initial commit adding support for the mxc6225 assumed the
mxc6225 has a chip-id of 0xe5 based on testing on a single Allwinner
A23 tablet with a mxc6225. Testing on a bunch of other Allwinner
tablets have shown that the chip-id for the mxc6225 is not constant.

A datasheet for the MXC6255 which I've found online says that bits
7 and 6 of the chip-id register are undefined (for the mxc6255), testing
on 5 different tablets with a mxc6225 has found the following ids:
0x25, 0x45, 0x65, 0x85, 0xe5. So it seems that for the mxc6225 bits
7, 6 and 5 of the chip-id register are undefined.

This commit adjusts the chip-id check so that the mxc6255 driver
properly recognizes the mxc6225 in all these tablets.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Diffstat (limited to 'drivers/iio')
-rw-r--r--drivers/iio/accel/mxc6255.c7
1 files changed, 1 insertions, 6 deletions
diff --git a/drivers/iio/accel/mxc6255.c b/drivers/iio/accel/mxc6255.c
index 50343a7818d6..0abad6948201 100644
--- a/drivers/iio/accel/mxc6255.c
+++ b/drivers/iio/accel/mxc6255.c
@@ -26,7 +26,6 @@
 #define MXC6255_REG_YOUT		0x01
 #define MXC6255_REG_CHIP_ID		0x08
 
-#define MXC6225_CHIP_ID			0xe5
 #define MXC6255_CHIP_ID			0x05
 
 /*
@@ -155,11 +154,7 @@ static int mxc6255_probe(struct i2c_client *client,
 		return ret;
 	}
 
-	switch (chip_id) {
-	case MXC6225_CHIP_ID:
-	case MXC6255_CHIP_ID:
-		break;
-	default:
+	if ((chip_id & 0x1f) != MXC6255_CHIP_ID) {
 		dev_err(&client->dev, "Invalid chip id %x\n", chip_id);
 		return -ENODEV;
 	}