4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Christophe Leroy christophe.leroy@c-s.fr
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: 0c36ec314735 ("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
--- drivers/gpio/gpio-max7301.c | 12 +++--------- 1 file changed, 3 insertions(+), 9 deletions(-)
--- a/drivers/gpio/gpio-max7301.c +++ b/drivers/gpio/gpio-max7301.c @@ -25,7 +25,7 @@ static int max7301_spi_write(struct devi 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 devic 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;