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Message-ID: <c54da9aa3edb841b1e3d5f2fbfd0b29e89da1184.camel@gmail.com>
Date: Tue, 17 Dec 2024 13:18:16 +0100
From: Nuno Sá <noname.nuno@...il.com>
To: David Lechner <dlechner@...libre.com>, Mark Brown <broonie@...nel.org>,
Jonathan Cameron
<jic23@...nel.org>, Rob Herring <robh@...nel.org>, Krzysztof Kozlowski
<krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>, Nuno
Sá
<nuno.sa@...log.com>
Cc: Uwe Kleine-König <ukleinek@...nel.org>, Michael
Hennerich <Michael.Hennerich@...log.com>, Lars-Peter Clausen
<lars@...afoo.de>, David Jander <david@...tonic.nl>, Martin Sperl
<kernel@...tin.sperl.org>, linux-spi@...r.kernel.org,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-iio@...r.kernel.org, linux-pwm@...r.kernel.org, Axel Haslam
<ahaslam@...libre.com>
Subject: Re: [PATCH v6 17/17] iio: dac: ad5791: Add offload support
On Wed, 2024-12-11 at 14:54 -0600, David Lechner wrote:
> From: Axel Haslam <ahaslam@...libre.com>
>
> Add SPI offload support to stream TX buffers using DMA.
> This allows loading samples to the DAC with a rate of 1 MSPS.
>
> Signed-off-by: Axel Haslam <ahaslam@...libre.com>
> Signed-off-by: David Lechner <dlechner@...libre.com>
> ---
Reviewed-by: Nuno Sa <nuno.sa@...log.com>
>
> v6 changes: new patch in v6
> ---
> drivers/iio/dac/Kconfig | 3 +
> drivers/iio/dac/ad5791.c | 150
> +++++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 153 insertions(+)
>
> diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig
> index
> 4cde34e8c8e3356aa41bcd2cba38d67d5c6f8049..f6c5cb632acbdc2432f60b163452bb0c5f89
> fa72 100644
> --- a/drivers/iio/dac/Kconfig
> +++ b/drivers/iio/dac/Kconfig
> @@ -296,6 +296,9 @@ config AD5770R
> config AD5791
> tristate "Analog Devices AD5760/AD5780/AD5781/AD5790/AD5791 DAC SPI
> driver"
> depends on SPI
> + select SPI_OFFLOAD
> + select IIO_BUFFER
> + select IIO_BUFFER_DMAENGINE
> help
> Say yes here to build support for Analog Devices AD5760, AD5780,
> AD5781, AD5790, AD5791 High Resolution Voltage Output Digital to
> diff --git a/drivers/iio/dac/ad5791.c b/drivers/iio/dac/ad5791.c
> index
> 24462cb020e19e8e2c6faa13109ac047cf423c37..a2953a9a4e5d5bc17c9c4a8281be4b41b1af
> 5de8 100644
> --- a/drivers/iio/dac/ad5791.c
> +++ b/drivers/iio/dac/ad5791.c
> @@ -15,9 +15,12 @@
> #include <linux/module.h>
> #include <linux/regulator/consumer.h>
> #include <linux/slab.h>
> +#include <linux/spi/offload/consumer.h>
> #include <linux/spi/spi.h>
> #include <linux/sysfs.h>
> +#include <linux/units.h>
>
> +#include <linux/iio/buffer-dmaengine.h>
> #include <linux/iio/dac/ad5791.h>
> #include <linux/iio/iio.h>
> #include <linux/iio/sysfs.h>
> @@ -64,11 +67,13 @@
> * struct ad5791_chip_info - chip specific information
> * @name: name of the dac chip
> * @channel: channel specification
> + * @channel_offload: channel specification for offload
> * @get_lin_comp: function pointer to the device specific function
> */
> struct ad5791_chip_info {
> const char *name;
> const struct iio_chan_spec channel;
> + const struct iio_chan_spec channel_offload;
> int (*get_lin_comp)(unsigned int span);
> };
>
> @@ -81,6 +86,11 @@ struct ad5791_chip_info {
> * @gpio_clear: clear gpio
> * @gpio_ldac: load dac gpio
> * @chip_info: chip model specific constants
> + * @offload_msg: spi message used for offload
> + * @offload_xfer: spi transfer used for offload
> + * @offload: offload device
> + * @offload_trigger: offload trigger
> + * @offload_trigger_hz: offload sample rate
> * @vref_mv: actual reference voltage used
> * @vref_neg_mv: voltage of the negative supply
> * @ctrl: control register cache
> @@ -96,6 +106,11 @@ struct ad5791_state {
> struct gpio_desc *gpio_clear;
> struct gpio_desc *gpio_ldac;
> const struct ad5791_chip_info *chip_info;
> + struct spi_message offload_msg;
> + struct spi_transfer offload_xfer;
> + struct spi_offload *offload;
> + struct spi_offload_trigger *offload_trigger;
> + unsigned int offload_trigger_hz;
> unsigned short vref_mv;
> unsigned int vref_neg_mv;
> unsigned ctrl;
> @@ -232,6 +247,25 @@ static int ad5780_get_lin_comp(unsigned int span)
> return AD5780_LINCOMP_10_20;
> }
>
> +static int ad5791_set_sample_freq(struct ad5791_state *st, int val)
> +{
> + struct spi_offload_trigger_config config = {
> + .type = SPI_OFFLOAD_TRIGGER_PERIODIC,
> + .periodic = {
> + .frequency_hz = val,
> + },
> + };
> + int ret;
> +
> + ret = spi_offload_trigger_validate(st->offload_trigger, &config);
> + if (ret)
> + return ret;
> +
> + st->offload_trigger_hz = config.periodic.frequency_hz;
> +
> + return 0;
> +}
> +
> static int ad5791_read_raw(struct iio_dev *indio_dev,
> struct iio_chan_spec const *chan,
> int *val,
> @@ -259,6 +293,9 @@ static int ad5791_read_raw(struct iio_dev *indio_dev,
> do_div(val64, st->vref_mv);
> *val = -val64;
> return IIO_VAL_INT;
> + case IIO_CHAN_INFO_SAMP_FREQ:
> + *val = st->offload_trigger_hz;
> + return IIO_VAL_INT;
> default:
> return -EINVAL;
> }
> @@ -299,6 +336,24 @@ static const struct ad5791_chip_info _name##_chip_info =
> { \
> }, \
> .ext_info = ad5791_ext_info, \
> }, \
> + .channel_offload = { \
> + .type = IIO_VOLTAGE, \
> + .output = 1, \
> + .indexed = 1, \
> + .address = AD5791_ADDR_DAC0, \
> + .channel = 0, \
> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
> + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE)
> | \
> + BIT(IIO_CHAN_INFO_OFFSET), \
> + .info_mask_shared_by_all =
> BIT(IIO_CHAN_INFO_SAMP_FREQ),\
> + .scan_type = { \
> + .sign = 'u', \
> + .realbits = (bits), \
> + .storagebits = 32, \
> + .shift = (_shift), \
> + }, \
> + .ext_info = ad5791_ext_info, \
> + }, \
> }
>
> AD5791_DEFINE_CHIP_INFO(ad5760, 16, 4, ad5780_get_lin_comp);
> @@ -322,16 +377,95 @@ static int ad5791_write_raw(struct iio_dev *indio_dev,
>
> return ad5791_spi_write(st, chan->address, val);
>
> + case IIO_CHAN_INFO_SAMP_FREQ:
> + if (val < 0 || val2 < 0)
> + return -EINVAL;
> + return ad5791_set_sample_freq(st, val);
> default:
> return -EINVAL;
> }
> }
>
> +static int ad5791_buffer_preenable(struct iio_dev *indio_dev)
> +{
> + struct ad5791_state *st = iio_priv(indio_dev);
> + struct spi_offload_trigger_config config = {
> + .type = SPI_OFFLOAD_TRIGGER_PERIODIC,
> + .periodic = {
> + .frequency_hz = st->offload_trigger_hz,
> + },
> + };
> +
> + if (st->pwr_down)
> + return -EINVAL;
> +
> + return spi_offload_trigger_enable(st->offload, st->offload_trigger,
> + &config);
> +}
> +
> +static int ad5791_buffer_postdisable(struct iio_dev *indio_dev)
> +{
> + struct ad5791_state *st = iio_priv(indio_dev);
> +
> + spi_offload_trigger_disable(st->offload, st->offload_trigger);
> +
> + return 0;
> +}
> +
> +static const struct iio_buffer_setup_ops ad5791_buffer_setup_ops = {
> + .preenable = &ad5791_buffer_preenable,
> + .postdisable = &ad5791_buffer_postdisable,
> +};
> +
> +static int ad5791_offload_setup(struct iio_dev *indio_dev)
> +{
> + struct ad5791_state *st = iio_priv(indio_dev);
> + struct spi_device *spi = st->spi;
> + struct dma_chan *tx_dma;
> + int ret;
> +
> + st->offload_trigger = devm_spi_offload_trigger_get(&spi->dev,
> + st->offload, SPI_OFFLOAD_TRIGGER_PERIODIC);
> + if (IS_ERR(st->offload_trigger))
> + return dev_err_probe(&spi->dev, PTR_ERR(st->offload_trigger),
> + "failed to get offload trigger\n");
> +
> + ret = ad5791_set_sample_freq(st, 1 * MEGA);
> + if (ret)
> + return dev_err_probe(&spi->dev, ret,
> + "failed to init sample rate\n");
> +
> + tx_dma = devm_spi_offload_tx_stream_request_dma_chan(&spi->dev,
> + st->offload);
> + if (IS_ERR(tx_dma))
> + return dev_err_probe(&spi->dev, PTR_ERR(tx_dma),
> + "failed to get offload TX DMA\n");
> +
> + ret = devm_iio_dmaengine_buffer_setup_with_handle(&spi->dev,
> + indio_dev, tx_dma, IIO_BUFFER_DIRECTION_OUT);
> + if (ret)
> + return ret;
> +
> + st->offload_xfer.len = 4;
> + st->offload_xfer.bits_per_word = 24;
> + st->offload_xfer.offload_flags = SPI_OFFLOAD_XFER_TX_STREAM;
> +
> + spi_message_init_with_transfers(&st->offload_msg, &st->offload_xfer,
> 1);
> + st->offload_msg.offload = st->offload;
> +
> + return devm_spi_optimize_message(&spi->dev, st->spi, &st-
> >offload_msg);
> +}
> +
> static const struct iio_info ad5791_info = {
> .read_raw = &ad5791_read_raw,
> .write_raw = &ad5791_write_raw,
> };
>
> +static const struct spi_offload_config ad5791_offload_config = {
> + .capability_flags = SPI_OFFLOAD_CAP_TRIGGER |
> + SPI_OFFLOAD_CAP_TX_STREAM_DMA,
> +};
> +
> static int ad5791_probe(struct spi_device *spi)
> {
> const struct ad5791_platform_data *pdata = dev_get_platdata(&spi-
> >dev);
> @@ -416,6 +550,21 @@ static int ad5791_probe(struct spi_device *spi)
> indio_dev->channels = &st->chip_info->channel;
> indio_dev->num_channels = 1;
> indio_dev->name = st->chip_info->name;
> +
> + st->offload = devm_spi_offload_get(&spi->dev, spi,
> &ad5791_offload_config);
> + ret = PTR_ERR_OR_ZERO(st->offload);
> + if (ret && ret != -ENODEV)
> + return dev_err_probe(&spi->dev, ret, "failed to get
> offload\n");
> +
> + if (ret != -ENODEV) {
> + indio_dev->channels = &st->chip_info->channel_offload;
> + indio_dev->setup_ops = &ad5791_buffer_setup_ops;
> + ret = ad5791_offload_setup(indio_dev);
> + if (ret)
> + return dev_err_probe(&spi->dev, ret,
> + "fail to setup offload\n");
> + }
> +
> return devm_iio_device_register(&spi->dev, indio_dev);
> }
>
> @@ -452,3 +601,4 @@ module_spi_driver(ad5791_driver);
> MODULE_AUTHOR("Michael Hennerich <michael.hennerich@...log.com>");
> MODULE_DESCRIPTION("Analog Devices AD5760/AD5780/AD5781/AD5790/AD5791 DAC");
> MODULE_LICENSE("GPL v2");
> +MODULE_IMPORT_NS("IIO_DMAENGINE_BUFFER");
>
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