Some SPI controllers may not be able to handle transfer buffers that are placed
on the stack.
Signed-off-by: Lars-Peter Clausen <lars@xxxxxxxxxx>
---
drivers/iio/dac/ad5791.c | 46 +++++++++++++++++++++-------------------------
1 file changed, 21 insertions(+), 25 deletions(-)
diff --git a/drivers/iio/dac/ad5791.c b/drivers/iio/dac/ad5791.c
index 1e7f4cd..79bf199 100644
--- a/drivers/iio/dac/ad5791.c
+++ b/drivers/iio/dac/ad5791.c
@@ -91,6 +91,11 @@ struct ad5791_state {
unsigned ctrl;
unsigned pwr_down_mode;
bool pwr_down;
+
+ union {
+ __be32 d32;
+ u8 d8[4];
+ } data[3] ____cacheline_aligned;
};
/**
@@ -104,48 +109,39 @@ enum ad5791_supported_device_ids {
ID_AD5791,
};
-static int ad5791_spi_write(struct spi_device *spi, u8 addr, u32 val)
+static int ad5791_spi_write(struct ad5791_state *st, u8 addr, u32 val)
{
- union {
- __be32 d32;
- u8 d8[4];
- } data;
-
- data.d32 = cpu_to_be32(AD5791_CMD_WRITE |
+ st->data[0].d32 = cpu_to_be32(AD5791_CMD_WRITE |
AD5791_ADDR(addr) |
(val & AD5791_DAC_MASK));
- return spi_write(spi, &data.d8[1], 3);
+ return spi_write(st->spi, &st->data[0].d8[1], 3);
}
-static int ad5791_spi_read(struct spi_device *spi, u8 addr, u32 *val)
+static int ad5791_spi_read(struct ad5791_state *st, u8 addr, u32 *val)
{
- union {
- __be32 d32;
- u8 d8[4];
- } data[3];
int ret;
struct spi_transfer xfers[] = {
{
- .tx_buf = &data[0].d8[1],
+ .tx_buf = &st->data[0].d8[1],
.bits_per_word = 8,
.len = 3,
.cs_change = 1,
}, {
- .tx_buf = &data[1].d8[1],
- .rx_buf = &data[2].d8[1],
+ .tx_buf = &st->data[1].d8[1],
+ .rx_buf = &st->data[2].d8[1],
.bits_per_word = 8,
.len = 3,
},
};
- data[0].d32 = cpu_to_be32(AD5791_CMD_READ |
+ st->data[0].d32 = cpu_to_be32(AD5791_CMD_READ |
AD5791_ADDR(addr));
- data[1].d32 = cpu_to_be32(AD5791_ADDR(AD5791_ADDR_NOOP));
+ st->data[1].d32 = cpu_to_be32(AD5791_ADDR(AD5791_ADDR_NOOP));
- ret = spi_sync_transfer(spi, xfers, ARRAY_SIZE(xfers));
+ ret = spi_sync_transfer(st->spi, xfers, ARRAY_SIZE(xfers));
- *val = be32_to_cpu(data[2].d32);
+ *val = be32_to_cpu(st->data[2].d32);
return ret;
}
@@ -210,7 +206,7 @@ static ssize_t ad5791_write_dac_powerdown(struct iio_dev *indio_dev,
}
st->pwr_down = pwr_down;
- ret = ad5791_spi_write(st->spi, AD5791_ADDR_CTRL, st->ctrl);
+ ret = ad5791_spi_write(st, AD5791_ADDR_CTRL, st->ctrl);
return ret ? ret : len;
}
@@ -263,7 +259,7 @@ static int ad5791_read_raw(struct iio_dev *indio_dev,
switch (m) {
case IIO_CHAN_INFO_RAW:
- ret = ad5791_spi_read(st->spi, chan->address, val);
+ ret = ad5791_spi_read(st, chan->address, val);
if (ret)
return ret;
*val &= AD5791_DAC_MASK;
@@ -330,7 +326,7 @@ static int ad5791_write_raw(struct iio_dev *indio_dev,
val &= AD5791_RES_MASK(chan->scan_type.realbits);
val <<= chan->scan_type.shift;
- return ad5791_spi_write(st->spi, chan->address, val);
+ return ad5791_spi_write(st, chan->address, val);
default:
return -EINVAL;
@@ -393,7 +389,7 @@ static int ad5791_probe(struct spi_device *spi)
dev_warn(&spi->dev, "reference voltage unspecified\n");
}
- ret = ad5791_spi_write(spi, AD5791_ADDR_SW_CTRL, AD5791_SWCTRL_RESET);
+ ret = ad5791_spi_write(st, AD5791_ADDR_SW_CTRL, AD5791_SWCTRL_RESET);
if (ret)
goto error_disable_reg_neg;
@@ -405,7 +401,7 @@ static int ad5791_probe(struct spi_device *spi)
| ((pdata && pdata->use_rbuf_gain2) ? 0 : AD5791_CTRL_RBUF) |
AD5791_CTRL_BIN2SC;
- ret = ad5791_spi_write(spi, AD5791_ADDR_CTRL, st->ctrl |
+ ret = ad5791_spi_write(st, AD5791_ADDR_CTRL, st->ctrl |
AD5791_CTRL_OPGND | AD5791_CTRL_DACTRI);
if (ret)
goto error_disable_reg_neg;
--
1.8.0
--
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