From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from saturn.retrosnub.co.uk ([178.18.118.26]:48274 "EHLO saturn.retrosnub.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751434Ab3K3LJq (ORCPT ); Sat, 30 Nov 2013 06:09:46 -0500 Message-ID: <5299C779.3070601@kernel.org> Date: Sat, 30 Nov 2013 11:09:45 +0000 From: Jonathan Cameron MIME-Version: 1.0 To: Lars-Peter Clausen CC: linux-iio@vger.kernel.org Subject: Re: [PATCH 07/15] iio:ad5791: Do not store transfer buffers on the stack References: <1385383327-28181-1-git-send-email-lars@metafoo.de> <1385383327-28181-7-git-send-email-lars@metafoo.de> In-Reply-To: <1385383327-28181-7-git-send-email-lars@metafoo.de> Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-iio-owner@vger.kernel.org List-Id: linux-iio@vger.kernel.org On 11/25/13 12:41, Lars-Peter Clausen wrote: > Some SPI controllers may not be able to handle transfer buffers that are placed > on the stack. > > Signed-off-by: Lars-Peter Clausen Applied to the togreg branch of iio.git Thanks > --- > 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 1e7f4cd..79bf199 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; >