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iio:ad5791: Do not store transfer buffers on the stack 

Some SPI controllers may not be able to handle transfer buffers that are placed
on the stack.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
This commit is contained in:
Lars-Peter Clausen 2013-11-25 12:41:00 +00:00 committed by Jonathan Cameron
parent ae8bb9b101
commit 791bb52a0c
1 changed files with 21 additions and 25 deletions
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46
drivers/iio/dac/ad5791.c
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@ -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;