Commit 3e3bed91 authored May 26, 2014 by Michael Stickel Committed by Linus Walleij May 27, 2014

gpio: mcp23s08: fixed count variable for devicetree probing



Fixed missing increase of count variable for devicetree path in driver
probing.

The gpio-mcp23s08 driver has two paths for getting the platform
registration information. One for the classic platform initialization
and one for openfirmware devicetree based initialization. The devicetree
based path is missing the increase of the count variable, which results
in the count variable to become negative in the later use, where it is
decreased. The count variable is used as an index into a vector. This
results in accessing invalid memory space and can result in an exception.

Tested this with an AM3352 SoC with two mcp23s17 on two chip selects as
well as on a shared chip select.

Signed-off-by: Michael Stickel <ms@mycable.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

parent 821e85f2

drivers/gpio/gpio-mcp23s08.c

+10 −1

Original line number	Diff line number	Diff line
		@@ -895,8 +895,13 @@ 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++;
		}
		if (!chips)
		return -ENODEV;
		} else {
		type = spi_get_device_id(spi)->driver_data;
		pdata = dev_get_platdata(&spi->dev);
		@@ -935,6 +940,10 @@ static int mcp23s08_probe(struct spi_device *spi)
		if (!(spi_present_mask & (1 << addr)))
		continue;
		chips--;
		if (chips < 0) {
		dev_err(&spi->dev, "FATAL: invalid negative chip id\n");
		goto fail;
		}
		data->mcp[addr] = &data->chip[chips];
		status = mcp23s08_probe_one(data->mcp[addr], &spi->dev, spi,
		0x40 \| (addr << 1), type, base,

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