| Message ID | 3f9179c9a1c8e2486cdd15d28530cd2e381a8830.1544152023.git.christophe.leroy@c-s.fr |
|---|---|
| State | New |
| Headers | show |
| Series | gpio: max7301: fix driver for use with CONFIG_VMAP_STACK | expand |
On Fri, Dec 7, 2018 at 2:07 PM Christophe Leroy <christophe.leroy@c-s.fr> 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: <stable@vger.kernel.org> > Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Patch applied for fixes. Yours, Linus Walleij
diff --git a/drivers/gpio/gpio-max7301.c b/drivers/gpio/gpio-max7301.c index 68c7942d0a3c..6f7d12ba2f74 100644 --- a/drivers/gpio/gpio-max7301.c +++ b/drivers/gpio/gpio-max7301.c @@ -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;
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> --- drivers/gpio/gpio-max7301.c | 12 +++--------- 1 file changed, 3 insertions(+), 9 deletions(-)