From 219da3ea842a156e5808176e11db256db9798f6c Mon Sep 17 00:00:00 2001 From: David Lechner Date: Tue, 1 Jul 2025 16:37:59 -0500 Subject: [PATCH] iio: adc: ad_sigma_delta: add SPI offload support MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Add SPI offload support to the ad_sigma_delta module. When the SPI controller has SPI offload capabilities, the module will now use that for buffered reads instead of the RDY interrupt trigger. Drivers that use the ad_sigma_delta module will have to opt into this by setting supports_spi_offload since each driver will likely need additional changes before SPI offload can be used. This will allow us to gradually enable SPI offload support for each driver. Signed-off-by: David Lechner Reviewed-by: Andy Shevchenko Reviewed-by: Nuno Sá Link: https://patch.msgid.link/20250701-iio-adc-ad7173-add-spi-offload-support-v3-11-42abb83e3dac@baylibre.com Signed-off-by: Jonathan Cameron --- drivers/iio/adc/ad_sigma_delta.c | 165 ++++++++++++++++++------- include/linux/iio/adc/ad_sigma_delta.h | 14 +++ 2 files changed, 132 insertions(+), 47 deletions(-) diff --git a/drivers/iio/adc/ad_sigma_delta.c b/drivers/iio/adc/ad_sigma_delta.c index 124c42e19f2e..9d2dba0a0ee6 100644 --- a/drivers/iio/adc/ad_sigma_delta.c +++ b/drivers/iio/adc/ad_sigma_delta.c @@ -20,6 +20,7 @@ #include #include #include +#include #include #include #include @@ -27,6 +28,7 @@ #include #include +#include #include #include #include @@ -467,8 +469,7 @@ static int ad_sd_buffer_postenable(struct iio_dev *indio_dev) struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); const struct iio_scan_type *scan_type = &indio_dev->channels[0].scan_type; struct spi_transfer *xfer = sigma_delta->sample_xfer; - unsigned int i, slot, samples_buf_size; - unsigned int channel, scan_size; + unsigned int i, slot, channel; u8 *samples_buf; int ret; @@ -496,25 +497,35 @@ static int ad_sd_buffer_postenable(struct iio_dev *indio_dev) sigma_delta->active_slots = slot; sigma_delta->current_slot = 0; - if (sigma_delta->active_slots > 1) { - ret = ad_sigma_delta_append_status(sigma_delta, true); - if (ret) - return ret; - } + if (ad_sigma_delta_has_spi_offload(sigma_delta)) { + xfer[1].offload_flags = SPI_OFFLOAD_XFER_RX_STREAM; + xfer[1].bits_per_word = scan_type->realbits; + xfer[1].len = spi_bpw_to_bytes(scan_type->realbits); + } else { + unsigned int samples_buf_size, scan_size; - samples_buf_size = ALIGN(slot * BITS_TO_BYTES(scan_type->storagebits), - sizeof(s64)); - samples_buf_size += sizeof(s64); - samples_buf = devm_krealloc(&sigma_delta->spi->dev, sigma_delta->samples_buf, - samples_buf_size, GFP_KERNEL); - if (!samples_buf) - return -ENOMEM; + if (sigma_delta->active_slots > 1) { + ret = ad_sigma_delta_append_status(sigma_delta, true); + if (ret) + return ret; + } - sigma_delta->samples_buf = samples_buf; - scan_size = BITS_TO_BYTES(scan_type->realbits + scan_type->shift); - /* For 24-bit data, there is an extra byte of padding. */ - xfer[1].rx_buf = &sigma_delta->rx_buf[scan_size == 3 ? 1 : 0]; - xfer[1].len = scan_size + (sigma_delta->status_appended ? 1 : 0); + samples_buf_size = + ALIGN(slot * BITS_TO_BYTES(scan_type->storagebits), + sizeof(s64)); + samples_buf_size += sizeof(s64); + samples_buf = devm_krealloc(&sigma_delta->spi->dev, + sigma_delta->samples_buf, + samples_buf_size, GFP_KERNEL); + if (!samples_buf) + return -ENOMEM; + + sigma_delta->samples_buf = samples_buf; + scan_size = BITS_TO_BYTES(scan_type->realbits + scan_type->shift); + /* For 24-bit data, there is an extra byte of padding. */ + xfer[1].rx_buf = &sigma_delta->rx_buf[scan_size == 3 ? 1 : 0]; + xfer[1].len = scan_size + (sigma_delta->status_appended ? 1 : 0); + } xfer[1].cs_change = 1; if (sigma_delta->info->has_registers) { @@ -530,6 +541,8 @@ static int ad_sd_buffer_postenable(struct iio_dev *indio_dev) &xfer[1], 1); } + sigma_delta->sample_msg.offload = sigma_delta->offload; + ret = spi_optimize_message(sigma_delta->spi, &sigma_delta->sample_msg); if (ret) return ret; @@ -546,7 +559,19 @@ static int ad_sd_buffer_postenable(struct iio_dev *indio_dev) if (ret) goto err_unlock; - ad_sd_enable_irq(sigma_delta); + if (ad_sigma_delta_has_spi_offload(sigma_delta)) { + struct spi_offload_trigger_config config = { + .type = SPI_OFFLOAD_TRIGGER_DATA_READY, + }; + + ret = spi_offload_trigger_enable(sigma_delta->offload, + sigma_delta->offload_trigger, + &config); + if (ret) + goto err_unlock; + } else { + ad_sd_enable_irq(sigma_delta); + } return 0; @@ -561,10 +586,15 @@ static int ad_sd_buffer_postdisable(struct iio_dev *indio_dev) { struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); - reinit_completion(&sigma_delta->completion); - wait_for_completion_timeout(&sigma_delta->completion, HZ); + if (ad_sigma_delta_has_spi_offload(sigma_delta)) { + spi_offload_trigger_disable(sigma_delta->offload, + sigma_delta->offload_trigger); + } else { + reinit_completion(&sigma_delta->completion); + wait_for_completion_timeout(&sigma_delta->completion, HZ); - ad_sd_disable_irq(sigma_delta); + ad_sd_disable_irq(sigma_delta); + } sigma_delta->keep_cs_asserted = false; ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE); @@ -679,7 +709,8 @@ static irqreturn_t ad_sd_data_rdy_trig_poll(int irq, void *private) if ((!sigma_delta->rdy_gpiod || gpiod_get_value(sigma_delta->rdy_gpiod)) && ad_sd_disable_irq(sigma_delta)) { complete(&sigma_delta->completion); - iio_trigger_poll(sigma_delta->trig); + if (sigma_delta->trig) + iio_trigger_poll(sigma_delta->trig); return IRQ_HANDLED; } @@ -712,17 +743,6 @@ static int devm_ad_sd_probe_trigger(struct device *dev, struct iio_dev *indio_de unsigned long irq_flags = irq_get_trigger_type(sigma_delta->irq_line); int ret; - if (dev != &sigma_delta->spi->dev) { - dev_err(dev, "Trigger parent should be '%s', got '%s'\n", - dev_name(dev), dev_name(&sigma_delta->spi->dev)); - return -EFAULT; - } - - sigma_delta->trig = devm_iio_trigger_alloc(dev, "%s-dev%d", indio_dev->name, - iio_device_id(indio_dev)); - if (sigma_delta->trig == NULL) - return -ENOMEM; - init_completion(&sigma_delta->completion); sigma_delta->irq_dis = true; @@ -742,14 +762,33 @@ static int devm_ad_sd_probe_trigger(struct device *dev, struct iio_dev *indio_de if (ret) return ret; - iio_trigger_set_drvdata(sigma_delta->trig, sigma_delta); + if (ad_sigma_delta_has_spi_offload(sigma_delta)) { + sigma_delta->offload_trigger = + devm_spi_offload_trigger_get(dev, sigma_delta->offload, + SPI_OFFLOAD_TRIGGER_DATA_READY); + if (IS_ERR(sigma_delta->offload_trigger)) + return dev_err_probe(dev, PTR_ERR(sigma_delta->offload_trigger), + "Failed to get SPI offload trigger\n"); + } else { + if (dev != &sigma_delta->spi->dev) + return dev_err_probe(dev, -EFAULT, + "Trigger parent should be '%s', got '%s'\n", + dev_name(dev), dev_name(&sigma_delta->spi->dev)); - ret = devm_iio_trigger_register(dev, sigma_delta->trig); - if (ret) - return ret; + sigma_delta->trig = devm_iio_trigger_alloc(dev, "%s-dev%d", + indio_dev->name, iio_device_id(indio_dev)); + if (!sigma_delta->trig) + return -ENOMEM; - /* select default trigger */ - indio_dev->trig = iio_trigger_get(sigma_delta->trig); + iio_trigger_set_drvdata(sigma_delta->trig, sigma_delta); + + ret = devm_iio_trigger_register(dev, sigma_delta->trig); + if (ret) + return ret; + + /* select default trigger */ + indio_dev->trig = iio_trigger_get(sigma_delta->trig); + } return 0; } @@ -769,12 +808,29 @@ int devm_ad_sd_setup_buffer_and_trigger(struct device *dev, struct iio_dev *indi if (!sigma_delta->slots) return -ENOMEM; - ret = devm_iio_triggered_buffer_setup(dev, indio_dev, - &iio_pollfunc_store_time, - &ad_sd_trigger_handler, - &ad_sd_buffer_setup_ops); - if (ret) - return ret; + if (ad_sigma_delta_has_spi_offload(sigma_delta)) { + struct dma_chan *rx_dma; + + rx_dma = devm_spi_offload_rx_stream_request_dma_chan(dev, + sigma_delta->offload); + if (IS_ERR(rx_dma)) + return dev_err_probe(dev, PTR_ERR(rx_dma), + "Failed to get RX DMA channel\n"); + + ret = devm_iio_dmaengine_buffer_setup_with_handle(dev, indio_dev, + rx_dma, IIO_BUFFER_DIRECTION_IN); + if (ret) + return dev_err_probe(dev, ret, "Cannot setup DMA buffer\n"); + + indio_dev->setup_ops = &ad_sd_buffer_setup_ops; + } else { + ret = devm_iio_triggered_buffer_setup(dev, indio_dev, + &iio_pollfunc_store_time, + &ad_sd_trigger_handler, + &ad_sd_buffer_setup_ops); + if (ret) + return ret; + } return devm_ad_sd_probe_trigger(dev, indio_dev); } @@ -837,6 +893,20 @@ int ad_sd_init(struct ad_sigma_delta *sigma_delta, struct iio_dev *indio_dev, return sigma_delta->irq_line; } + if (info->supports_spi_offload) { + struct spi_offload_config offload_config = { + .capability_flags = SPI_OFFLOAD_CAP_TRIGGER | + SPI_OFFLOAD_CAP_RX_STREAM_DMA, + }; + int ret; + + sigma_delta->offload = devm_spi_offload_get(&spi->dev, spi, + &offload_config); + ret = PTR_ERR_OR_ZERO(sigma_delta->offload); + if (ret && ret != -ENODEV) + return dev_err_probe(&spi->dev, ret, "Failed to get SPI offload\n"); + } + iio_device_set_drvdata(indio_dev, sigma_delta); return 0; @@ -846,3 +916,4 @@ EXPORT_SYMBOL_NS_GPL(ad_sd_init, "IIO_AD_SIGMA_DELTA"); MODULE_AUTHOR("Lars-Peter Clausen "); MODULE_DESCRIPTION("Analog Devices Sigma-Delta ADCs"); MODULE_LICENSE("GPL v2"); +MODULE_IMPORT_NS("IIO_DMAENGINE_BUFFER"); diff --git a/include/linux/iio/adc/ad_sigma_delta.h b/include/linux/iio/adc/ad_sigma_delta.h index 2037bb68b441..6e70a412e218 100644 --- a/include/linux/iio/adc/ad_sigma_delta.h +++ b/include/linux/iio/adc/ad_sigma_delta.h @@ -31,6 +31,8 @@ struct ad_sigma_delta; struct device; struct gpio_desc; struct iio_dev; +struct spi_offload; +struct spi_offload_trigger; /** * struct ad_sigma_delta_info - Sigma Delta driver specific callbacks and options @@ -47,6 +49,10 @@ struct iio_dev; * @has_registers: true if the device has writable and readable registers, false * if there is just one read-only sample data shift register. * @has_named_irqs: Set to true if there is more than one IRQ line. + * @supports_spi_offload: Set to true if the driver supports SPI offload. Often + * special considerations are needed for scan_type and other channel + * info, so individual drivers have to set this to let the core + * code know that it can use SPI offload if it is available. * @addr_shift: Shift of the register address in the communications register. * @read_mask: Mask for the communications register having the read bit set. * @status_ch_mask: Mask for the channel number stored in status register. @@ -65,6 +71,7 @@ struct ad_sigma_delta_info { int (*postprocess_sample)(struct ad_sigma_delta *, unsigned int raw_sample); bool has_registers; bool has_named_irqs; + bool supports_spi_offload; unsigned int addr_shift; unsigned int read_mask; unsigned int status_ch_mask; @@ -108,6 +115,8 @@ struct ad_sigma_delta { struct spi_message sample_msg; struct spi_transfer sample_xfer[2]; u8 *samples_buf; + struct spi_offload *offload; + struct spi_offload_trigger *offload_trigger; /* * DMA (thus cache coherency maintenance) requires the @@ -121,6 +130,11 @@ struct ad_sigma_delta { u8 sample_addr; }; +static inline bool ad_sigma_delta_has_spi_offload(struct ad_sigma_delta *sd) +{ + return sd->offload != NULL; +} + static inline int ad_sigma_delta_set_channel(struct ad_sigma_delta *sd, unsigned int channel) { -- 2.47.2