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: 0c36ec3147
("gpio: gpio driver for max7301 SPI GPIO expander")
Cc: <stable@vger.kernel.org>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
parent
a5c4aa9ca5
commit
61b4285244
1 changed files with 3 additions and 9 deletions
|
@ -25,7 +25,7 @@ static int max7301_spi_write(struct device *dev, unsigned int reg,
|
||||||
struct spi_device *spi = to_spi_device(dev);
|
struct spi_device *spi = to_spi_device(dev);
|
||||||
u16 word = ((reg & 0x7F) << 8) | (val & 0xFF);
|
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 */
|
/* 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);
|
struct spi_device *spi = to_spi_device(dev);
|
||||||
|
|
||||||
word = 0x8000 | (reg << 8);
|
word = 0x8000 | (reg << 8);
|
||||||
ret = spi_write(spi, (const u8 *)&word, sizeof(word));
|
ret = spi_write_then_read(spi, &word, sizeof(word), &word,
|
||||||
if (ret)
|
sizeof(word));
|
||||||
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));
|
|
||||||
if (ret)
|
if (ret)
|
||||||
return ret;
|
return ret;
|
||||||
return word & 0xff;
|
return word & 0xff;
|
||||||
|
|
Loading…
Add table
Reference in a new issue