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iio:ad5504: 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 61c358e3bc
commit 0dbe59c7a7
1 changed files with 19 additions and 19 deletions
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38
drivers/iio/dac/ad5504.c
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@ -47,14 +47,16 @@
* @vref_mv: actual reference voltage used
* @pwr_down_mask power down mask
* @pwr_down_mode current power down mode
* @data: transfer buffer
*/
struct ad5504_state {
struct spi_device *spi;
struct regulator *reg;
unsigned short vref_mv;
unsigned pwr_down_mask;
unsigned pwr_down_mode;
__be16 data[2] ____cacheline_aligned;
};
/**
@ -66,31 +68,29 @@ enum ad5504_supported_device_ids {
ID_AD5501,
};
static int ad5504_spi_write(struct spi_device *spi, u8 addr, u16 val)
static int ad5504_spi_write(struct ad5504_state *st, u8 addr, u16 val)
{
__be16 tmp = cpu_to_be16(AD5504_CMD_WRITE |
AD5504_ADDR(addr) |
st->data[0] = cpu_to_be16(AD5504_CMD_WRITE | AD5504_ADDR(addr) |
(val & AD5504_RES_MASK));
return spi_write(spi, (u8 *)&tmp, 2);
return spi_write(st->spi, &st->data[0], 2);
}
static int ad5504_spi_read(struct spi_device *spi, u8 addr)
static int ad5504_spi_read(struct ad5504_state *st, u8 addr)
{
__be16 tmp = cpu_to_be16(AD5504_CMD_READ | AD5504_ADDR(addr));
__be16 val;
int ret;
struct spi_transfer t = {
.tx_buf = &tmp,
.rx_buf = &val,
.len = 2,
};
ret = spi_sync_transfer(spi, &t, 1);
struct spi_transfer t = {
.tx_buf = &st->data[0],
.rx_buf = &st->data[1],
.len = 2,
};
st->data[0] = cpu_to_be16(AD5504_CMD_READ | AD5504_ADDR(addr));
ret = spi_sync_transfer(st->spi, &t, 1);
if (ret < 0)
return ret;
return be16_to_cpu(val) & AD5504_RES_MASK;
return be16_to_cpu(st->data[1]) & AD5504_RES_MASK;
}
static int ad5504_read_raw(struct iio_dev *indio_dev,
@ -104,7 +104,7 @@ static int ad5504_read_raw(struct iio_dev *indio_dev,
switch (m) {
case IIO_CHAN_INFO_RAW:
ret = ad5504_spi_read(st->spi, chan->address);
ret = ad5504_spi_read(st, chan->address);
if (ret < 0)
return ret;
@ -133,7 +133,7 @@ static int ad5504_write_raw(struct iio_dev *indio_dev,
if (val >= (1 << chan->scan_type.realbits) || val < 0)
return -EINVAL;
return ad5504_spi_write(st->spi, chan->address, val);
return ad5504_spi_write(st, chan->address, val);
default:
ret = -EINVAL;
}
@ -197,12 +197,12 @@ static ssize_t ad5504_write_dac_powerdown(struct iio_dev *indio_dev,
else
st->pwr_down_mask &= ~(1 << chan->channel);
ret = ad5504_spi_write(st->spi, AD5504_ADDR_CTRL,
ret = ad5504_spi_write(st, AD5504_ADDR_CTRL,
AD5504_DAC_PWRDWN_MODE(st->pwr_down_mode) |
AD5504_DAC_PWR(st->pwr_down_mask));
/* writes to the CTRL register must be followed by a NOOP */
ad5504_spi_write(st->spi, AD5504_ADDR_NOOP, 0);
ad5504_spi_write(st, AD5504_ADDR_NOOP, 0);
return ret ? ret : len;
}