On Fri, Dec 7, 2018 at 2:07 PM Christophe Leroy [off-list ref] wrote:

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: <redacted>
Signed-off-by: Christophe Leroy <redacted>

Patch applied for fixes.

Yours,
Linus Walleij