[PATCH] mfd: mc13xxx-spi: make SPI buffers DMA-safe

[Marcus Folkesson]

Signed-off-by: Marcus Folkesson <marcus.folkes...@gmail.com>
---
 drivers/mfd/mc13xxx-spi.c | 14 +++++++-------
 drivers/mfd/mc13xxx.h     |  4 ++++
 2 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/drivers/mfd/mc13xxx-spi.c b/drivers/mfd/mc13xxx-spi.c
index cbc1e5ed599c..f6bfbee9d9ef 100644
--- a/drivers/mfd/mc13xxx-spi.c
+++ b/drivers/mfd/mc13xxx-spi.c
@@ -63,14 +63,13 @@ static const struct regmap_config mc13xxx_regmap_spi_config 
= {
 static int mc13xxx_spi_read(void *context, const void *reg, size_t reg_size,
                                void *val, size_t val_size)
 {
-       unsigned char w[4] = { *((unsigned char *) reg), 0, 0, 0};
-       unsigned char r[4];
        unsigned char *p = val;
        struct device *dev = context;
        struct spi_device *spi = to_spi_device(dev);
+       struct mc13xxx *mc13xxx = dev_get_drvdata(dev);
        struct spi_transfer t = {
-               .tx_buf = w,
-               .rx_buf = r,
+               .tx_buf = mc13xxx->wbuf,
+               .rx_buf = mc13xxx->rbuf,
                .len = 4,
        };
 
@@ -80,11 +79,12 @@ static int mc13xxx_spi_read(void *context, const void *reg, 
size_t reg_size,
        if (val_size != 3 || reg_size != 1)
                return -ENOTSUPP;
 
+       mc13xxx->wbuf[0] = *(unsigned char *)reg;
        spi_message_init(&m);
        spi_message_add_tail(&t, &m);
        ret = spi_sync(spi, &m);
 
-       memcpy(p, &r[1], 3);
+       memcpy(p, &mc13xxx->rbuf[1], 3);
 
        return ret;
 }
@@ -100,9 +100,9 @@ static int mc13xxx_spi_write(void *context, const void 
*data, size_t count)
 
        /* include errata fix for spi audio problems */
        if (*reg == MC13783_AUDIO_CODEC || *reg == MC13783_AUDIO_DAC)
-               spi_write(spi, data, count);
+               spi_write_then_read(spi, data, count, NULL, 0);
 
-       return spi_write(spi, data, count);
+       return spi_write_then_read(spi, data, count, NULL, 0);
 }
 
 /*
diff --git a/drivers/mfd/mc13xxx.h b/drivers/mfd/mc13xxx.h
index 33677d1dcf66..1b35632e1d7e 100644
--- a/drivers/mfd/mc13xxx.h
+++ b/drivers/mfd/mc13xxx.h
@@ -44,6 +44,10 @@ struct mc13xxx {
        int flags;
 
        int adcflags;
+#ifdef CONFIG_MFD_MC13XXX_SPI
+       unsigned char wbuf[4] ____cacheline_aligned;
+       unsigned char rbuf[4];
+#endif
 };
 
 int mc13xxx_common_init(struct device *dev);
-- 
2.11.0.rc2