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Commit 791bb52a authored by Lars-Peter Clausen's avatar Lars-Peter Clausen Committed by Jonathan Cameron
Browse files

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: default avatarLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent ae8bb9b1

drivers/iio/dac/ad5791.c

+21 −25
Original line number Diff line number Diff line
@@ -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;