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

From: Marcus Folkesson
Date: Fri Dec 09 2016 - 05:31:33 EST


Signed-off-by: Marcus Folkesson <marcus.folkesson@xxxxxxxxx>
---
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