[PATCH 3.12 059/111] gpio: mcp23s08: Bug fix of SPI device tree registration.

[Jiri Slaby]

From: Michael Welling <mwelling@xxxxxxxx>

3.12-stable review patch.  If anyone has any objections, please let me know.

===============

commit 99e4b98dbe3ad1fe38a74d12c3b8d44a55930de4 upstream.

The chips variable needs to be incremented for each chip that is
found in the spi_present_mask when registering via device tree.
Without this and the checking a negative index is passed to the
data->chip array in a subsequent loop.

Signed-off-by: Michael Welling <mwelling@xxxxxxxx>
Acked-by: Peter Korsgaard <peter@xxxxxxxxxxxxx>
Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
 drivers/gpio/gpio-mcp23s08.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/gpio/gpio-mcp23s08.c b/drivers/gpio/gpio-mcp23s08.c
index 2deb0c5e54a4..380fedb7d93c 100644
--- a/drivers/gpio/gpio-mcp23s08.c
+++ b/drivers/gpio/gpio-mcp23s08.c
@@ -657,8 +657,11 @@ static int mcp23s08_probe(struct spi_device *spi)
 			return -ENODEV;
 		}
 
-		for (addr = 0; addr < ARRAY_SIZE(pdata->chip); addr++)
+		for (addr = 0; addr < ARRAY_SIZE(pdata->chip); addr++) {
 			pullups[addr] = 0;
+			if (spi_present_mask & (1 << addr))
+				chips++;
+		}
 	} else {
 		type = spi_get_device_id(spi)->driver_data;
 		pdata = dev_get_platdata(&spi->dev);
@@ -681,12 +684,12 @@ static int mcp23s08_probe(struct spi_device *spi)
 			pullups[addr] = pdata->chip[addr].pullups;
 		}
 
-		if (!chips)
-			return -ENODEV;
-
 		base = pdata->base;
 	}
 
+	if (!chips)
+		return -ENODEV;
+
 	data = kzalloc(sizeof *data + chips * sizeof(struct mcp23s08),
 			GFP_KERNEL);
 	if (!data)
-- 
2.0.0

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