Commit 0dbe59c7 authored by Lars-Peter Clausen's avatar Lars-Peter Clausen Committed by Jonathan Cameron
Browse files

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: default avatarLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent 61c358e3

drivers/iio/dac/ad5504.c

+20 −20
Original line number Diff line number Diff line
@@ -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,

	    .tx_buf = &st->data[0],

	    .rx_buf = &st->data[1],

	    .len = 2,

	};

	ret = spi_sync_transfer(spi, &t, 1);



	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;

}