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Commit 07cfa7ac authored by Christophe Leroy's avatar Christophe Leroy Committed by Greg Kroah-Hartman
Browse files

gpio: max7301: fix driver for use with CONFIG_VMAP_STACK 



commit abf221d2f51b8ce7b9959a8953f880a8b0a1400d upstream.

spi_read() and spi_write() require DMA-safe memory. When
CONFIG_VMAP_STACK is selected, those functions cannot be used
with buffers on stack.

This patch replaces calls to spi_read() and spi_write() by
spi_write_then_read() which doesn't require DMA-safe buffers.

Fixes: 0c36ec31 ("gpio: gpio driver for max7301 SPI GPIO expander")
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 4d7a081d

drivers/gpio/gpio-max7301.c

+3 −9
Original line number Diff line number Diff line
@@ -25,7 +25,7 @@ static int max7301_spi_write(struct device *dev, unsigned int reg, 
	struct spi_device *spi = to_spi_device(dev);

	u16 word = ((reg & 0x7F) << 8) | (val & 0xFF);



	return spi_write(spi, (const u8 *)&word, sizeof(word));

	return spi_write_then_read(spi, &word, sizeof(word), NULL, 0);

}



/* A read from the MAX7301 means two transfers; here, one message each */
@@ -37,14 +37,8 @@ static int max7301_spi_read(struct device *dev, unsigned int reg) 
	struct spi_device *spi = to_spi_device(dev);



	word = 0x8000 | (reg << 8);

	ret = spi_write(spi, (const u8 *)&word, sizeof(word));

	if (ret)

		return ret;

	/*

	 * This relies on the fact, that a transfer with NULL tx_buf shifts out

	 * zero bytes (=NOOP for MAX7301)

	 */

	ret = spi_read(spi, (u8 *)&word, sizeof(word));

	ret = spi_write_then_read(spi, &word, sizeof(word), &word,

				  sizeof(word));

	if (ret)

		return ret;

	return word & 0xff;