From 791bb52a0cd2cc95f030e461cfafe26448bc6618 Mon Sep 17 00:00:00 2001 From: Lars-Peter Clausen Date: Mon, 25 Nov 2013 12:41:00 +0000 Subject: 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 Signed-off-by: Jonathan Cameron --- 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 1e7f4cd7db83..79bf19945747 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; -- cgit v1.2.3