[PATCH 0/3] iio: ad7606: add SPI offload support

[PATCH 0/3] iio: ad7606: add SPI offload support

[Angelo Dureghello]

Add SPI offload support for the ad7606 ADC.

Signed-off-by: Angelo Dureghello <adureghello@baylibre.com>
---
Angelo Dureghello (3):
      dt-bindings: iio: adc: adi,ad7606: add SPI offload properties
      doc: iio: ad7606: describe offload support
      iio: adc: ad7606: add SPI offload support

 .../devicetree/bindings/iio/adc/adi,ad7606.yaml    |   8 +
 Documentation/iio/ad7606.rst                       |  45 +++++
 drivers/iio/adc/Kconfig                            |   2 +
 drivers/iio/adc/ad7606.c                           |  50 ++++-
 drivers/iio/adc/ad7606.h                           |  12 ++
 drivers/iio/adc/ad7606_spi.c                       | 210 +++++++++++++++++++++
 include/dt-bindings/iio/adc/adi,ad7606.h           |   9 +
 7 files changed, 326 insertions(+), 10 deletions(-)
---
base-commit: 8f159ea5a253d40682e041daec007933d6caf01b
change-id: 20250403-wip-bl-spi-offload-ad7606-cfd992d286a4

Best regards,
-- 
Angelo Dureghello <adureghello@baylibre.com>

[PATCH 1/3] dt-bindings: iio: adc: adi,ad7606: add SPI offload properties

[Angelo Dureghello]

From: Angelo Dureghello <adureghello@baylibre.com>

Add #trigger-source-cells property to allow the BUSY output to be
used as a SPI offload trigger source to indicate when a sample is ready
to be read.

Macros are added to adi,ad7606.h for the cell values to help with
readability since they are arbitrary values.

Signed-off-by: Angelo Dureghello <adureghello@baylibre.com>
---
 Documentation/devicetree/bindings/iio/adc/adi,ad7606.yaml | 8 ++++++++
 include/dt-bindings/iio/adc/adi,ad7606.h                  | 9 +++++++++
 2 files changed, 17 insertions(+)

diff --git a/Documentation/devicetree/bindings/iio/adc/adi,ad7606.yaml b/Documentation/devicetree/bindings/iio/adc/adi,ad7606.yaml
index 52d3f1ce336783084d601d361779ebc766124f7a..29f12d650442b8ff2eb455306ce59a0e87867ddd 100644
--- a/Documentation/devicetree/bindings/iio/adc/adi,ad7606.yaml
+++ b/Documentation/devicetree/bindings/iio/adc/adi,ad7606.yaml
@@ -45,6 +45,14 @@ properties:
   "#size-cells":
     const: 0
 
+  '#trigger-source-cells':
+    description: |
+      Cell indicates the output signal: 0 = BUSY, 1 = FIRSTDATA.
+
+      For convenience, macros for these values are available in
+      dt-bindings/iio/adc/adi,ad7606.h.
+    const: 1
+
   # According to the datasheet, "Data is clocked in from SDI on the falling
   # edge of SCLK, while data is clocked out on DOUTA on the rising edge of
   # SCLK".  Also, even if not stated textually in the datasheet, it is made
diff --git a/include/dt-bindings/iio/adc/adi,ad7606.h b/include/dt-bindings/iio/adc/adi,ad7606.h
new file mode 100644
index 0000000000000000000000000000000000000000..f38a6d72b6dc2d4067c07d6a5c0377e526219e5c
--- /dev/null
+++ b/include/dt-bindings/iio/adc/adi,ad7606.h
@@ -0,0 +1,9 @@
+/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) */
+
+#ifndef _DT_BINDINGS_ADI_AD7606_H
+#define _DT_BINDINGS_ADI_AD7606_H
+
+#define AD7606_TRIGGER_EVENT_BUSY	0
+#define AD7606_TRIGGER_EVENT_FRSTDATA	1
+
+#endif /* _DT_BINDINGS_ADI_AD7606_H */

-- 
2.49.0

[PATCH 2/3] doc: iio: ad7606: describe offload support

[Angelo Dureghello]

From: Angelo Dureghello <adureghello@baylibre.com>

Add a section to the ad7606 documentation describing how to use the
driver with SPI offloading.

Signed-off-by: Angelo Dureghello <adureghello@baylibre.com>
---
 Documentation/iio/ad7606.rst | 45 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 45 insertions(+)

diff --git a/Documentation/iio/ad7606.rst b/Documentation/iio/ad7606.rst
index 930199e03c67f68296ec83176f9e4f82741fb813..5e02516bab406b6b13d2ebd13a33433e3e86d943 100644
--- a/Documentation/iio/ad7606.rst
+++ b/Documentation/iio/ad7606.rst
@@ -26,6 +26,35 @@ SPI wiring modes
 These ADCs can output data on several SDO lines (1/2/4/8). The driver
 currently supports only 1 SDO line.
 
+SPI offload wiring
+------------------
+When used with a SPI offload, the supported wiring configuration is:
+
+.. code-block::
+
+    +-------------+         +-------------+
+    |        BUSY |-------->| TRIGGER     |
+    |          CS |<--------| CS          |
+    |             |         |             |
+    |     ADC     |         |     SPI     |
+    |             |         |             |
+    |         SDI |<--------| SDO         |
+    |       DOUTA |-------->| SDI         |
+    |        SCLK |<--------| SCLK        |
+    |             |         |             |
+    |             |         +-------------+
+    |      CONVST |<--------| PWM         |
+    +-------------+         +-------------+
+
+In this case, the ``pwms`` property is required.
+The ``#trigger-source-cells = <1>`` property is also required to connect back
+to the SPI offload. The SPI offload will have ``trigger-sources`` property
+with a cell to indicate the busy signal:
+``<&ad7606 AD4695_TRIGGER_EVENT_BUSY>``.
+
+.. seealso:: `SPI offload support`_
+
+
 Parallel wiring mode
 --------------------
 
@@ -123,6 +152,22 @@ Unimplemented features
 - CRC indication
 - Calibration
 
+SPI offload support
+===================
+
+To be able to achieve the maximum sample rate, the driver can be used with the
+`AXI SPI Engine`_ to provide SPI offload support.
+
+.. _AXI SPI Engine: https://analogdevicesinc.github.io/hdl/library/spi_engine/index.html
+
+When SPI offload is being used, some attributes will be different.
+
+* ``trigger`` directory is removed.
+* ``sampling_frequency`` attribute is added for setting the sample rate.
+* ``timestamp`` channel is removed.
+* Buffer data format may be different compared to when offload is not used,
+  e.g. the ``in_voltage0_type`` attribute.
+
 Device buffers
 ==============
 

-- 
2.49.0

[PATCH 3/3] iio: adc: ad7606: add SPI offload support

[Angelo Dureghello]

From: Angelo Dureghello <adureghello@baylibre.com>

Add SPI offload support for this family.

Signed-off-by: Angelo Dureghello <adureghello@baylibre.com>
---
 drivers/iio/adc/Kconfig      |   2 +
 drivers/iio/adc/ad7606.c     |  50 ++++++++---
 drivers/iio/adc/ad7606.h     |  12 +++
 drivers/iio/adc/ad7606_spi.c | 210 +++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 264 insertions(+), 10 deletions(-)

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 859c77f40f1d1893d0fc92212ad538150f0992c8..df90db609f683217cffaeb605aa9b6f022cf2b9b 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -284,6 +284,8 @@ config AD7606_IFACE_SPI
 	tristate "Analog Devices AD7606 ADC driver with spi interface support"
 	depends on SPI
 	select AD7606
+	select IIO_BUFFER_DMAENGINE
+	select SPI_OFFLOAD
 	help
 	  Say yes here to build spi interface support for Analog Devices:
 	  ad7605-4, ad7606, ad7606-6, ad7606-4 analog to digital converters (ADC).
diff --git a/drivers/iio/adc/ad7606.c b/drivers/iio/adc/ad7606.c
index 843c30fddc7346d0dec7d791e26ca16e2c1ea0cf..aa6ae2c1b06acfa5d38229827e37fed1c2f82870 100644
--- a/drivers/iio/adc/ad7606.c
+++ b/drivers/iio/adc/ad7606.c
@@ -138,6 +138,7 @@ const struct ad7606_chip_info ad7606_6_info = {
 	.oversampling_avail = ad7606_oversampling_avail,
 	.oversampling_num = ARRAY_SIZE(ad7606_oversampling_avail),
 	.scale_setup_cb = ad7606_16bit_chan_scale_setup,
+	.offload_storagebits = 32,
 };
 EXPORT_SYMBOL_NS_GPL(ad7606_6_info, "IIO_AD7606");
 
@@ -149,6 +150,7 @@ const struct ad7606_chip_info ad7606_4_info = {
 	.oversampling_avail = ad7606_oversampling_avail,
 	.oversampling_num = ARRAY_SIZE(ad7606_oversampling_avail),
 	.scale_setup_cb = ad7606_16bit_chan_scale_setup,
+	.offload_storagebits = 32,
 };
 EXPORT_SYMBOL_NS_GPL(ad7606_4_info, "IIO_AD7606");
 
@@ -161,6 +163,7 @@ const struct ad7606_chip_info ad7606b_info = {
 	.oversampling_num = ARRAY_SIZE(ad7606_oversampling_avail),
 	.scale_setup_cb = ad7606_16bit_chan_scale_setup,
 	.sw_setup_cb = ad7606b_sw_mode_setup,
+	.offload_storagebits = 32,
 };
 EXPORT_SYMBOL_NS_GPL(ad7606b_info, "IIO_AD7606");
 
@@ -173,6 +176,7 @@ const struct ad7606_chip_info ad7606c_16_info = {
 	.oversampling_num = ARRAY_SIZE(ad7606_oversampling_avail),
 	.scale_setup_cb = ad7606c_16bit_chan_scale_setup,
 	.sw_setup_cb = ad7606b_sw_mode_setup,
+	.offload_storagebits = 32,
 };
 EXPORT_SYMBOL_NS_GPL(ad7606c_16_info, "IIO_AD7606");
 
@@ -184,6 +188,7 @@ const struct ad7606_chip_info ad7607_info = {
 	.oversampling_avail = ad7606_oversampling_avail,
 	.oversampling_num = ARRAY_SIZE(ad7606_oversampling_avail),
 	.scale_setup_cb = ad7607_chan_scale_setup,
+	.offload_storagebits = 32,
 };
 EXPORT_SYMBOL_NS_GPL(ad7607_info, "IIO_AD7606");
 
@@ -195,6 +200,7 @@ const struct ad7606_chip_info ad7608_info = {
 	.oversampling_avail = ad7606_oversampling_avail,
 	.oversampling_num = ARRAY_SIZE(ad7606_oversampling_avail),
 	.scale_setup_cb = ad7608_chan_scale_setup,
+	.offload_storagebits = 32,
 };
 EXPORT_SYMBOL_NS_GPL(ad7608_info, "IIO_AD7606");
 
@@ -206,6 +212,7 @@ const struct ad7606_chip_info ad7609_info = {
 	.oversampling_avail = ad7606_oversampling_avail,
 	.oversampling_num = ARRAY_SIZE(ad7606_oversampling_avail),
 	.scale_setup_cb = ad7609_chan_scale_setup,
+	.offload_storagebits = 32,
 };
 EXPORT_SYMBOL_NS_GPL(ad7609_info, "IIO_AD7606");
 
@@ -218,6 +225,7 @@ const struct ad7606_chip_info ad7606c_18_info = {
 	.oversampling_num = ARRAY_SIZE(ad7606_oversampling_avail),
 	.scale_setup_cb = ad7606c_18bit_chan_scale_setup,
 	.sw_setup_cb = ad7606b_sw_mode_setup,
+	.offload_storagebits = 32,
 };
 EXPORT_SYMBOL_NS_GPL(ad7606c_18_info, "IIO_AD7606");
 
@@ -232,6 +240,7 @@ const struct ad7606_chip_info ad7616_info = {
 	.os_req_reset = true,
 	.scale_setup_cb = ad7606_16bit_chan_scale_setup,
 	.sw_setup_cb = ad7616_sw_mode_setup,
+	.offload_storagebits = 16,
 };
 EXPORT_SYMBOL_NS_GPL(ad7616_info, "IIO_AD7606");
 
@@ -514,7 +523,7 @@ static int ad7606_pwm_set_high(struct ad7606_state *st)
 	return ret;
 }
 
-static int ad7606_pwm_set_low(struct ad7606_state *st)
+int ad7606_pwm_set_low(struct ad7606_state *st)
 {
 	struct pwm_state cnvst_pwm_state;
 	int ret;
@@ -527,8 +536,9 @@ static int ad7606_pwm_set_low(struct ad7606_state *st)
 
 	return ret;
 }
+EXPORT_SYMBOL_NS_GPL(ad7606_pwm_set_low, "IIO_AD7606");
 
-static int ad7606_pwm_set_swing(struct ad7606_state *st)
+int ad7606_pwm_set_swing(struct ad7606_state *st)
 {
 	struct pwm_state cnvst_pwm_state;
 
@@ -538,6 +548,7 @@ static int ad7606_pwm_set_swing(struct ad7606_state *st)
 
 	return pwm_apply_might_sleep(st->cnvst_pwm, &cnvst_pwm_state);
 }
+EXPORT_SYMBOL_NS_GPL(ad7606_pwm_set_swing, "IIO_AD7606");
 
 static bool ad7606_pwm_is_swinging(struct ad7606_state *st)
 {
@@ -626,7 +637,7 @@ static int ad7606_scan_direct(struct iio_dev *indio_dev, unsigned int ch,
 	 * will not happen because IIO_CHAN_INFO_RAW is not supported for the backend.
 	 * TODO: Add support for reading a single value when the backend is used.
 	 */
-	if (!st->back) {
+	if (st->trig) {
 		ret = wait_for_completion_timeout(&st->completion,
 						  msecs_to_jiffies(1000));
 		if (!ret) {
@@ -634,7 +645,12 @@ static int ad7606_scan_direct(struct iio_dev *indio_dev, unsigned int ch,
 			goto error_ret;
 		}
 	} else {
-		fsleep(1);
+		/*
+		 * If the BUSY interrupt is not available, wait enough time for
+		 * the longest possible conversion (max for the whole family is
+		 * around 350us).
+		 */
+		fsleep(400);
 	}
 
 	ret = ad7606_read_samples(st);
@@ -1201,7 +1217,7 @@ static int ad7606_probe_channels(struct iio_dev *indio_dev)
 	bool slow_bus;
 	int ret, i;
 
-	slow_bus = !st->bops->iio_backend_config;
+	slow_bus = !(st->bops->iio_backend_config || st->offload_en);
 	indio_dev->num_channels = st->chip_info->num_adc_channels;
 
 	/* Slow buses also get 1 more channel for soft timestamp */
@@ -1222,7 +1238,14 @@ static int ad7606_probe_channels(struct iio_dev *indio_dev)
 		chan->scan_index = i;
 		chan->scan_type.sign = 's';
 		chan->scan_type.realbits = st->chip_info->bits;
-		chan->scan_type.storagebits = st->chip_info->bits > 16 ? 32 : 16;
+		/*
+		 * If in SPI offload mode, storagebits are set based
+		 * on the spi-engine hw implementation.
+		 */
+		chan->scan_type.storagebits = st->offload_en ?
+			st->chip_info->offload_storagebits :
+			(st->chip_info->bits > 16 ? 32 : 16);
+
 		chan->scan_type.endianness = IIO_CPU;
 
 		if (indio_dev->modes & INDIO_DIRECT_MODE)
@@ -1340,6 +1363,13 @@ int ad7606_probe(struct device *dev, int irq, void __iomem *base_address,
 	indio_dev->modes = st->bops->iio_backend_config ? 0 : INDIO_DIRECT_MODE;
 	indio_dev->name = chip_info->name;
 
+	/* Using spi-engine with offload support ? */
+	if (st->bops->offload_config) {
+		ret = st->bops->offload_config(dev, indio_dev);
+		if (ret)
+			return ret;
+	}
+
 	ret = ad7606_probe_channels(indio_dev);
 	if (ret)
 		return ret;
@@ -1355,7 +1385,7 @@ int ad7606_probe(struct device *dev, int irq, void __iomem *base_address,
 	}
 
 	/* If convst pin is not defined, setup PWM. */
-	if (!st->gpio_convst) {
+	if (!st->gpio_convst || st->offload_en) {
 		st->cnvst_pwm = devm_pwm_get(dev, NULL);
 		if (IS_ERR(st->cnvst_pwm))
 			return PTR_ERR(st->cnvst_pwm);
@@ -1394,8 +1424,7 @@ int ad7606_probe(struct device *dev, int irq, void __iomem *base_address,
 			return ret;
 
 		indio_dev->setup_ops = &ad7606_backend_buffer_ops;
-	} else {
-
+	} else if (!st->offload_en) {
 		/* Reserve the PWM use only for backend (force gpio_convst definition) */
 		if (!st->gpio_convst)
 			return dev_err_probe(dev, -EINVAL,
@@ -1433,7 +1462,8 @@ int ad7606_probe(struct device *dev, int irq, void __iomem *base_address,
 	st->write_scale = ad7606_write_scale_hw;
 	st->write_os = ad7606_write_os_hw;
 
-	if (st->sw_mode_en) {
+	/* Offload needs 1 DOUT line, applying this setting in sw_setup_cb. */
+	if (st->sw_mode_en || st->offload_en) {
 		indio_dev->info = &ad7606_info_sw_mode;
 		st->chip_info->sw_setup_cb(indio_dev);
 	}
diff --git a/drivers/iio/adc/ad7606.h b/drivers/iio/adc/ad7606.h
index f0b262fb4554f0bf244338c98ca585143321d616..89d49551eaf515bab9706c12bff056dfcb707b67 100644
--- a/drivers/iio/adc/ad7606.h
+++ b/drivers/iio/adc/ad7606.h
@@ -60,6 +60,7 @@ typedef int (*ad7606_sw_setup_cb_t)(struct iio_dev *indio_dev);
  * @os_req_reset:	some devices require a reset to update oversampling
  * @init_delay_ms:	required delay in milliseconds for initialization
  *			after a restart
+ * @offload_storagebits: storage bits used by the offload hw implementation
  */
 struct ad7606_chip_info {
 	unsigned int			max_samplerate;
@@ -72,6 +73,7 @@ struct ad7606_chip_info {
 	unsigned int			oversampling_num;
 	bool				os_req_reset;
 	unsigned long			init_delay_ms;
+	u8				offload_storagebits;
 };
 
 /**
@@ -118,6 +120,8 @@ struct ad7606_chan_scale {
  * @trig:		The IIO trigger associated with the device.
  * @completion:		completion to indicate end of conversion
  * @data:		buffer for reading data from the device
+ * @offload_en:		SPI offload enabled
+ * @bus_data:		bus-specific variables
  * @d16:		be16 buffer for reading data from the device
  */
 struct ad7606_state {
@@ -145,6 +149,9 @@ struct ad7606_state {
 	struct iio_trigger		*trig;
 	struct completion		completion;
 
+	bool				offload_en;
+	void				*bus_data;
+
 	/*
 	 * DMA (thus cache coherency maintenance) may require the
 	 * transfer buffers to live in their own cache lines.
@@ -165,6 +172,8 @@ struct ad7606_state {
  * @read_block:		function pointer for reading blocks of data
  * @sw_mode_config:	pointer to a function which configured the device
  *			for software mode
+ * @offload_config:     function pointer for configuring offload support,
+ *			where any
  * @reg_read:		function pointer for reading spi register
  * @reg_write:		function pointer for writing spi register
  * @update_scan_mode:	function pointer for handling the calls to iio_info's
@@ -174,6 +183,7 @@ struct ad7606_state {
 struct ad7606_bus_ops {
 	/* more methods added in future? */
 	int (*iio_backend_config)(struct device *dev, struct iio_dev *indio_dev);
+	int (*offload_config)(struct device *dev, struct iio_dev *indio_dev);
 	int (*read_block)(struct device *dev, int num, void *data);
 	int (*sw_mode_config)(struct iio_dev *indio_dev);
 	int (*reg_read)(struct ad7606_state *st, unsigned int addr);
@@ -199,6 +209,8 @@ int ad7606_probe(struct device *dev, int irq, void __iomem *base_address,
 		 const struct ad7606_bus_ops *bops);
 
 int ad7606_reset(struct ad7606_state *st);
+int ad7606_pwm_set_swing(struct ad7606_state *st);
+int ad7606_pwm_set_low(struct ad7606_state *st);
 
 extern const struct ad7606_chip_info ad7605_4_info;
 extern const struct ad7606_chip_info ad7606_8_info;
diff --git a/drivers/iio/adc/ad7606_spi.c b/drivers/iio/adc/ad7606_spi.c
index b2b975fb7fea4d1af6caef59e75ca495501bc140..b086122497eb22042171580878160334f56baa23 100644
--- a/drivers/iio/adc/ad7606_spi.c
+++ b/drivers/iio/adc/ad7606_spi.c
@@ -6,15 +6,31 @@
  */
 
 #include <linux/err.h>
+#include <linux/math.h>
 #include <linux/module.h>
+#include <linux/pwm.h>
+#include <linux/spi/offload/consumer.h>
+#include <linux/spi/offload/provider.h>
 #include <linux/spi/spi.h>
 #include <linux/types.h>
+#include <linux/units.h>
 
+#include <linux/iio/buffer-dmaengine.h>
 #include <linux/iio/iio.h>
+
+#include <dt-bindings/iio/adc/adi,ad7606.h>
+
 #include "ad7606.h"
 
 #define MAX_SPI_FREQ_HZ		23500000	/* VDRIVE above 4.75 V */
 
+struct spi_bus_data {
+	struct spi_offload *offload;
+	struct spi_offload_trigger *offload_trigger;
+	struct spi_transfer offload_xfer;
+	struct spi_message offload_msg;
+};
+
 static u16 ad7616_spi_rd_wr_cmd(int addr, char is_write_op)
 {
 	/*
@@ -125,19 +141,211 @@ static int ad7606b_sw_mode_config(struct iio_dev *indio_dev)
 				   AD7606_SINGLE_DOUT);
 }
 
+static const struct spi_offload_config ad7606_spi_offload_config = {
+	.capability_flags = SPI_OFFLOAD_CAP_TRIGGER |
+			    SPI_OFFLOAD_CAP_RX_STREAM_DMA,
+};
+
+static int ad7606_spi_offload_buffer_postenable(struct iio_dev *indio_dev)
+{
+	const struct iio_scan_type *scan_type;
+	struct ad7606_state *st = iio_priv(indio_dev);
+	struct spi_bus_data *bus_data = st->bus_data;
+	struct spi_transfer *xfer = &bus_data->offload_xfer;
+	struct spi_device *spi = to_spi_device(st->dev);
+	struct spi_offload_trigger_config config = {
+		.type = SPI_OFFLOAD_TRIGGER_DATA_READY,
+	};
+	int ret;
+
+	scan_type = &indio_dev->channels[0].scan_type;
+
+	xfer->bits_per_word = scan_type->realbits;
+	xfer->offload_flags = SPI_OFFLOAD_XFER_RX_STREAM;
+	/*
+	 * Using SPI offload, storagebits are related to the spi-engine
+	 * hw implementation, can be 16 or 32, so can't be used to compute
+	 * struct spi_transfer.len. Using realbits instead.
+	 */
+	xfer->len = (scan_type->realbits > 16 ? 4 : 2) *
+		    st->chip_info->num_adc_channels;
+
+	spi_message_init_with_transfers(&bus_data->offload_msg, xfer, 1);
+	bus_data->offload_msg.offload = bus_data->offload;
+
+	ret = spi_optimize_message(spi, &bus_data->offload_msg);
+	if (ret) {
+		dev_err(st->dev, "failed to prepare offload, err: %d\n", ret);
+		return ret;
+	}
+
+	ret = spi_offload_trigger_enable(bus_data->offload,
+					 bus_data->offload_trigger,
+					 &config);
+	if (ret)
+		goto err_unoptimize_message;
+
+	ret = ad7606_pwm_set_swing(st);
+	if (ret)
+		goto err_offload_exit_conversion_mode;
+
+	return 0;
+
+err_offload_exit_conversion_mode:
+	spi_offload_trigger_disable(bus_data->offload,
+				    bus_data->offload_trigger);
+
+err_unoptimize_message:
+	spi_unoptimize_message(&bus_data->offload_msg);
+
+	return ret;
+}
+
+static int ad7606_spi_offload_buffer_predisable(struct iio_dev *indio_dev)
+{
+	struct ad7606_state *st = iio_priv(indio_dev);
+	struct spi_bus_data *bus_data = st->bus_data;
+	int ret;
+
+	ret = ad7606_pwm_set_low(st);
+	if (ret)
+		return ret;
+
+	spi_offload_trigger_disable(bus_data->offload,
+				    bus_data->offload_trigger);
+	spi_unoptimize_message(&bus_data->offload_msg);
+
+	return 0;
+}
+
+static const struct iio_buffer_setup_ops ad7606_offload_buffer_setup_ops = {
+	.postenable = ad7606_spi_offload_buffer_postenable,
+	.predisable = ad7606_spi_offload_buffer_predisable,
+};
+
+static bool ad7606_spi_offload_trigger_match(
+				struct spi_offload_trigger *trigger,
+				enum spi_offload_trigger_type type,
+				u64 *args, u32 nargs)
+{
+	if (type != SPI_OFFLOAD_TRIGGER_DATA_READY)
+	       return false;
+
+	/*
+	 * Requires 1 arg:
+	 * args[0] is the trigger event.
+	 */
+	if (nargs != 1 || args[0] != AD7606_TRIGGER_EVENT_BUSY)
+		return false;
+
+	return true;
+}
+
+static int ad7606_spi_offload_trigger_request(
+				struct spi_offload_trigger *trigger,
+				enum spi_offload_trigger_type type,
+				u64 *args, u32 nargs)
+{
+	/* Should already be validated by match, but just in case. */
+	if (nargs != 1)
+		return -EINVAL;
+
+	return 0;
+}
+
+static int ad7606_spi_offload_trigger_validate(
+				struct spi_offload_trigger *trigger,
+				struct spi_offload_trigger_config *config)
+{
+	if (config->type != SPI_OFFLOAD_TRIGGER_DATA_READY)
+		return -EINVAL;
+
+	return 0;
+}
+
+static const struct spi_offload_trigger_ops ad7606_offload_trigger_ops = {
+	.match = ad7606_spi_offload_trigger_match,
+	.request = ad7606_spi_offload_trigger_request,
+	.validate = ad7606_spi_offload_trigger_validate,
+};
+
+static int ad7606_spi_offload_probe(struct device *dev,
+				    struct iio_dev *indio_dev)
+{
+	struct ad7606_state *st = iio_priv(indio_dev);
+	struct spi_device *spi = to_spi_device(dev);
+	struct spi_bus_data *bus_data;
+	struct dma_chan *rx_dma;
+	struct spi_offload_trigger_info trigger_info = {
+		.fwnode = dev_fwnode(dev),
+		.ops = &ad7606_offload_trigger_ops,
+		.priv = st,
+	};
+	int ret;
+
+	bus_data = devm_kzalloc(dev, sizeof(*bus_data), GFP_KERNEL);
+	if (!bus_data)
+		return -ENOMEM;
+	st->bus_data = bus_data;
+
+	bus_data->offload = devm_spi_offload_get(dev, spi,
+						 &ad7606_spi_offload_config);
+	ret = PTR_ERR_OR_ZERO(bus_data->offload);
+	if (ret && ret != -ENODEV)
+		return dev_err_probe(dev, ret, "failed to get SPI offload\n");
+	/* Allow main ad7606_probe function to continue. */
+	if (ret == -ENODEV)
+		return 0;
+
+	ret = devm_spi_offload_trigger_register(dev, &trigger_info);
+	if (ret)
+		return dev_err_probe(dev, ret,
+				     "failed to register offload trigger\n");
+
+	bus_data->offload_trigger = devm_spi_offload_trigger_get(dev,
+		bus_data->offload, SPI_OFFLOAD_TRIGGER_DATA_READY);
+	if (IS_ERR(bus_data->offload_trigger))
+		return dev_err_probe(dev, PTR_ERR(bus_data->offload_trigger),
+				     "failed to get offload trigger\n");
+
+	/* TODO: PWM setup should be ok, done for the backend. PWM mutex ? */
+	rx_dma = devm_spi_offload_rx_stream_request_dma_chan(dev,
+							     bus_data->offload);
+	if (IS_ERR(rx_dma))
+		return dev_err_probe(dev, PTR_ERR(rx_dma),
+				     "failed to get offload RX DMA\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, PTR_ERR(rx_dma),
+				     "failed to setup offload RX DMA\n");
+
+	/* Use offload ops. */
+	indio_dev->setup_ops = &ad7606_offload_buffer_setup_ops;
+
+	st->offload_en = true;
+
+	return 0;
+}
+
 static const struct ad7606_bus_ops ad7606_spi_bops = {
+	.offload_config = ad7606_spi_offload_probe,
 	.read_block = ad7606_spi_read_block,
 };
 
 static const struct ad7606_bus_ops ad7607_spi_bops = {
+	.offload_config = ad7606_spi_offload_probe,
 	.read_block = ad7606_spi_read_block14to16,
 };
 
 static const struct ad7606_bus_ops ad7608_spi_bops = {
+	.offload_config = ad7606_spi_offload_probe,
 	.read_block = ad7606_spi_read_block18to32,
 };
 
 static const struct ad7606_bus_ops ad7616_spi_bops = {
+	.offload_config = ad7606_spi_offload_probe,
 	.read_block = ad7606_spi_read_block,
 	.reg_read = ad7606_spi_reg_read,
 	.reg_write = ad7606_spi_reg_write,
@@ -145,6 +353,7 @@ static const struct ad7606_bus_ops ad7616_spi_bops = {
 };
 
 static const struct ad7606_bus_ops ad7606b_spi_bops = {
+	.offload_config = ad7606_spi_offload_probe,
 	.read_block = ad7606_spi_read_block,
 	.reg_read = ad7606_spi_reg_read,
 	.reg_write = ad7606_spi_reg_write,
@@ -153,6 +362,7 @@ static const struct ad7606_bus_ops ad7606b_spi_bops = {
 };
 
 static const struct ad7606_bus_ops ad7606c_18_spi_bops = {
+	.offload_config = ad7606_spi_offload_probe,
 	.read_block = ad7606_spi_read_block18to32,
 	.reg_read = ad7606_spi_reg_read,
 	.reg_write = ad7606_spi_reg_write,

-- 
2.49.0

Re: [PATCH 0/3] iio: ad7606: add SPI offload support

[David Lechner]

On 4/3/25 11:19 AM, Angelo Dureghello wrote:
> Add SPI offload support for the ad7606 ADC.
> 
> Signed-off-by: Angelo Dureghello <adureghello@baylibre.com>
> ---

Reviewed-by: David Lechner <dlechner@baylibre.com>

Re: [PATCH 3/3] iio: adc: ad7606: add SPI offload support

[Jonathan Cameron]

On Thu, 03 Apr 2025 18:19:06 +0200
Angelo Dureghello <adureghello@baylibre.com> wrote:

> From: Angelo Dureghello <adureghello@baylibre.com>
> 
> Add SPI offload support for this family.
> 
> Signed-off-by: Angelo Dureghello <adureghello@baylibre.com>
Hi Angelo,

Code looks fine, but there is a TODO I'd like to know more about
as it sounds 'ominous'. 

Otherwise this needs a dt review for patch 1 before I queue it up.

Jonathan
> diff --git a/drivers/iio/adc/ad7606_spi.c b/drivers/iio/adc/ad7606_spi.c
> index b2b975fb7fea4d1af6caef59e75ca495501bc140..b086122497eb22042171580878160334f56baa23 100644
> --- a/drivers/iio/adc/ad7606_spi.c
> +++ b/drivers/iio/adc/ad7606_spi.c

> +static int ad7606_spi_offload_probe(struct device *dev,
> +				    struct iio_dev *indio_dev)
> +{
> +	struct ad7606_state *st = iio_priv(indio_dev);
> +	struct spi_device *spi = to_spi_device(dev);
> +	struct spi_bus_data *bus_data;
> +	struct dma_chan *rx_dma;
> +	struct spi_offload_trigger_info trigger_info = {
> +		.fwnode = dev_fwnode(dev),
> +		.ops = &ad7606_offload_trigger_ops,
> +		.priv = st,
> +	};
> +	int ret;
> +
> +	bus_data = devm_kzalloc(dev, sizeof(*bus_data), GFP_KERNEL);
> +	if (!bus_data)
> +		return -ENOMEM;
> +	st->bus_data = bus_data;
> +
> +	bus_data->offload = devm_spi_offload_get(dev, spi,
> +						 &ad7606_spi_offload_config);
> +	ret = PTR_ERR_OR_ZERO(bus_data->offload);
> +	if (ret && ret != -ENODEV)
> +		return dev_err_probe(dev, ret, "failed to get SPI offload\n");
> +	/* Allow main ad7606_probe function to continue. */
> +	if (ret == -ENODEV)
> +		return 0;
> +
> +	ret = devm_spi_offload_trigger_register(dev, &trigger_info);
> +	if (ret)
> +		return dev_err_probe(dev, ret,
> +				     "failed to register offload trigger\n");
> +
> +	bus_data->offload_trigger = devm_spi_offload_trigger_get(dev,
> +		bus_data->offload, SPI_OFFLOAD_TRIGGER_DATA_READY);
> +	if (IS_ERR(bus_data->offload_trigger))
> +		return dev_err_probe(dev, PTR_ERR(bus_data->offload_trigger),
> +				     "failed to get offload trigger\n");
> +
> +	/* TODO: PWM setup should be ok, done for the backend. PWM mutex ? */

I don't understand this todo. Perhaps some more details?

> +	rx_dma = devm_spi_offload_rx_stream_request_dma_chan(dev,
> +							     bus_data->offload);
> +	if (IS_ERR(rx_dma))
> +		return dev_err_probe(dev, PTR_ERR(rx_dma),
> +				     "failed to get offload RX DMA\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, PTR_ERR(rx_dma),
> +				     "failed to setup offload RX DMA\n");
> +
> +	/* Use offload ops. */
> +	indio_dev->setup_ops = &ad7606_offload_buffer_setup_ops;
> +
> +	st->offload_en = true;
> +
> +	return 0;
> +}

Re: [PATCH 3/3] iio: adc: ad7606: add SPI offload support

[Angelo Dureghello]

Hi Jonathan,

On 05.04.2025 16:40, Jonathan Cameron wrote:
> On Thu, 03 Apr 2025 18:19:06 +0200
> Angelo Dureghello <adureghello@baylibre.com> wrote:
> 
> > From: Angelo Dureghello <adureghello@baylibre.com>
> > 
> > Add SPI offload support for this family.
> > 
> > Signed-off-by: Angelo Dureghello <adureghello@baylibre.com>
> Hi Angelo,
> 
> Code looks fine, but there is a TODO I'd like to know more about
> as it sounds 'ominous'. 
> 
> Otherwise this needs a dt review for patch 1 before I queue it up.
> 
> Jonathan
> > diff --git a/drivers/iio/adc/ad7606_spi.c b/drivers/iio/adc/ad7606_spi.c
> > index b2b975fb7fea4d1af6caef59e75ca495501bc140..b086122497eb22042171580878160334f56baa23 100644
> > --- a/drivers/iio/adc/ad7606_spi.c
> > +++ b/drivers/iio/adc/ad7606_spi.c
> 
> > +static int ad7606_spi_offload_probe(struct device *dev,
> > +				    struct iio_dev *indio_dev)
> > +{
> > +	struct ad7606_state *st = iio_priv(indio_dev);
> > +	struct spi_device *spi = to_spi_device(dev);
> > +	struct spi_bus_data *bus_data;
> > +	struct dma_chan *rx_dma;
> > +	struct spi_offload_trigger_info trigger_info = {
> > +		.fwnode = dev_fwnode(dev),
> > +		.ops = &ad7606_offload_trigger_ops,
> > +		.priv = st,
> > +	};
> > +	int ret;
> > +
> > +	bus_data = devm_kzalloc(dev, sizeof(*bus_data), GFP_KERNEL);
> > +	if (!bus_data)
> > +		return -ENOMEM;
> > +	st->bus_data = bus_data;
> > +
> > +	bus_data->offload = devm_spi_offload_get(dev, spi,
> > +						 &ad7606_spi_offload_config);
> > +	ret = PTR_ERR_OR_ZERO(bus_data->offload);
> > +	if (ret && ret != -ENODEV)
> > +		return dev_err_probe(dev, ret, "failed to get SPI offload\n");
> > +	/* Allow main ad7606_probe function to continue. */
> > +	if (ret == -ENODEV)
> > +		return 0;
> > +
> > +	ret = devm_spi_offload_trigger_register(dev, &trigger_info);
> > +	if (ret)
> > +		return dev_err_probe(dev, ret,
> > +				     "failed to register offload trigger\n");
> > +
> > +	bus_data->offload_trigger = devm_spi_offload_trigger_get(dev,
> > +		bus_data->offload, SPI_OFFLOAD_TRIGGER_DATA_READY);
> > +	if (IS_ERR(bus_data->offload_trigger))
> > +		return dev_err_probe(dev, PTR_ERR(bus_data->offload_trigger),
> > +				     "failed to get offload trigger\n");
> > +
> > +	/* TODO: PWM setup should be ok, done for the backend. PWM mutex ? */
> 
> I don't understand this todo. Perhaps some more details?
>
it was just an initial comment i did, when i started the things
was not clear.
Let me know if you can remove it, or i can send a v2.

Thanks a lot.

Regards,
angelo
 
> > +	rx_dma = devm_spi_offload_rx_stream_request_dma_chan(dev,
> > +							     bus_data->offload);
> > +	if (IS_ERR(rx_dma))
> > +		return dev_err_probe(dev, PTR_ERR(rx_dma),
> > +				     "failed to get offload RX DMA\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, PTR_ERR(rx_dma),
> > +				     "failed to setup offload RX DMA\n");
> > +
> > +	/* Use offload ops. */
> > +	indio_dev->setup_ops = &ad7606_offload_buffer_setup_ops;
> > +
> > +	st->offload_en = true;
> > +
> > +	return 0;
> > +}
> 
> 

Re: [PATCH 1/3] dt-bindings: iio: adc: adi,ad7606: add SPI offload properties

[Rob Herring (Arm)]

On Thu, 03 Apr 2025 18:19:04 +0200, Angelo Dureghello wrote:
> From: Angelo Dureghello <adureghello@baylibre.com>
> 
> Add #trigger-source-cells property to allow the BUSY output to be
> used as a SPI offload trigger source to indicate when a sample is ready
> to be read.
> 
> Macros are added to adi,ad7606.h for the cell values to help with
> readability since they are arbitrary values.
> 
> Signed-off-by: Angelo Dureghello <adureghello@baylibre.com>
> ---
>  Documentation/devicetree/bindings/iio/adc/adi,ad7606.yaml | 8 ++++++++
>  include/dt-bindings/iio/adc/adi,ad7606.h                  | 9 +++++++++
>  2 files changed, 17 insertions(+)
> 

Reviewed-by: Rob Herring (Arm) <robh@kernel.org>

Re: [PATCH 0/3] iio: ad7606: add SPI offload support

[Jonathan Cameron]

On Thu, 3 Apr 2025 11:48:09 -0500
David Lechner <dlechner@baylibre.com> wrote:

> On 4/3/25 11:19 AM, Angelo Dureghello wrote:
> > Add SPI offload support for the ad7606 ADC.
> > 
> > Signed-off-by: Angelo Dureghello <adureghello@baylibre.com>
> > ---  
> 
> Reviewed-by: David Lechner <dlechner@baylibre.com>
> 

Dropped the todo and applied to the togreg branch of iio.git.
Initially pushed out as testing for 0-day to work it's magic.

Thanks,

Jonathan

Re: [PATCH 3/3] iio: adc: ad7606: add SPI offload support

[Jonathan Cameron]

On Thu, 03 Apr 2025 18:19:06 +0200
Angelo Dureghello <adureghello@baylibre.com> wrote:

> From: Angelo Dureghello <adureghello@baylibre.com>
> 
> Add SPI offload support for this family.
> 
> Signed-off-by: Angelo Dureghello <adureghello@baylibre.com>
Missing import of the IIO_DMAENGINE_BUFFER in the spi module.

Added.

Re: [PATCH 3/3] iio: adc: ad7606: add SPI offload support

[Jonathan Cameron]

> +static int ad7606_spi_offload_probe(struct device *dev,
> +				    struct iio_dev *indio_dev)
> +{
> +	struct ad7606_state *st = iio_priv(indio_dev);
> +	struct spi_device *spi = to_spi_device(dev);
> +	struct spi_bus_data *bus_data;
> +	struct dma_chan *rx_dma;
> +	struct spi_offload_trigger_info trigger_info = {
> +		.fwnode = dev_fwnode(dev),
> +		.ops = &ad7606_offload_trigger_ops,
> +		.priv = st,
> +	};
> +	int ret;
> +
> +	bus_data = devm_kzalloc(dev, sizeof(*bus_data), GFP_KERNEL);
> +	if (!bus_data)
> +		return -ENOMEM;
> +	st->bus_data = bus_data;
> +
> +	bus_data->offload = devm_spi_offload_get(dev, spi,
> +						 &ad7606_spi_offload_config);
> +	ret = PTR_ERR_OR_ZERO(bus_data->offload);
> +	if (ret && ret != -ENODEV)
> +		return dev_err_probe(dev, ret, "failed to get SPI offload\n");
> +	/* Allow main ad7606_probe function to continue. */
> +	if (ret == -ENODEV)
> +		return 0;
> +
> +	ret = devm_spi_offload_trigger_register(dev, &trigger_info);
> +	if (ret)
> +		return dev_err_probe(dev, ret,
> +				     "failed to register offload trigger\n");
> +
> +	bus_data->offload_trigger = devm_spi_offload_trigger_get(dev,
> +		bus_data->offload, SPI_OFFLOAD_TRIGGER_DATA_READY);
> +	if (IS_ERR(bus_data->offload_trigger))
> +		return dev_err_probe(dev, PTR_ERR(bus_data->offload_trigger),
> +				     "failed to get offload trigger\n");
> +
> +	/* TODO: PWM setup should be ok, done for the backend. PWM mutex ? */
> +	rx_dma = devm_spi_offload_rx_stream_request_dma_chan(dev,
> +							     bus_data->offload);
> +	if (IS_ERR(rx_dma))
> +		return dev_err_probe(dev, PTR_ERR(rx_dma),
> +				     "failed to get offload RX DMA\n");
> +
> +	ret = devm_iio_dmaengine_buffer_setup_with_handle(dev, indio_dev,
> +		rx_dma, IIO_BUFFER_DIRECTION_IN);
> +	if (ret)

should be ret;  Thanks to 0-day for the report and fixed up.

> +		return dev_err_probe(dev, PTR_ERR(rx_dma),
> +				     "failed to setup offload RX DMA\n");
> +
> +	/* Use offload ops. */
> +	indio_dev->setup_ops = &ad7606_offload_buffer_setup_ops;
> +
> +	st->offload_en = true;
> +
> +	return 0;
> +}

Re: [PATCH 3/3] iio: adc: ad7606: add SPI offload support

[Angelo Dureghello]

On 14.04.2025 19:24, Jonathan Cameron wrote:
> 
> > +static int ad7606_spi_offload_probe(struct device *dev,
> > +				    struct iio_dev *indio_dev)
> > +{
> > +	struct ad7606_state *st = iio_priv(indio_dev);
> > +	struct spi_device *spi = to_spi_device(dev);
> > +	struct spi_bus_data *bus_data;
> > +	struct dma_chan *rx_dma;
> > +	struct spi_offload_trigger_info trigger_info = {
> > +		.fwnode = dev_fwnode(dev),
> > +		.ops = &ad7606_offload_trigger_ops,
> > +		.priv = st,
> > +	};
> > +	int ret;
> > +
> > +	bus_data = devm_kzalloc(dev, sizeof(*bus_data), GFP_KERNEL);
> > +	if (!bus_data)
> > +		return -ENOMEM;
> > +	st->bus_data = bus_data;
> > +
> > +	bus_data->offload = devm_spi_offload_get(dev, spi,
> > +						 &ad7606_spi_offload_config);
> > +	ret = PTR_ERR_OR_ZERO(bus_data->offload);
> > +	if (ret && ret != -ENODEV)
> > +		return dev_err_probe(dev, ret, "failed to get SPI offload\n");
> > +	/* Allow main ad7606_probe function to continue. */
> > +	if (ret == -ENODEV)
> > +		return 0;
> > +
> > +	ret = devm_spi_offload_trigger_register(dev, &trigger_info);
> > +	if (ret)
> > +		return dev_err_probe(dev, ret,
> > +				     "failed to register offload trigger\n");
> > +
> > +	bus_data->offload_trigger = devm_spi_offload_trigger_get(dev,
> > +		bus_data->offload, SPI_OFFLOAD_TRIGGER_DATA_READY);
> > +	if (IS_ERR(bus_data->offload_trigger))
> > +		return dev_err_probe(dev, PTR_ERR(bus_data->offload_trigger),
> > +				     "failed to get offload trigger\n");
> > +
> > +	/* TODO: PWM setup should be ok, done for the backend. PWM mutex ? */
> > +	rx_dma = devm_spi_offload_rx_stream_request_dma_chan(dev,
> > +							     bus_data->offload);
> > +	if (IS_ERR(rx_dma))
> > +		return dev_err_probe(dev, PTR_ERR(rx_dma),
> > +				     "failed to get offload RX DMA\n");
> > +
> > +	ret = devm_iio_dmaengine_buffer_setup_with_handle(dev, indio_dev,
> > +		rx_dma, IIO_BUFFER_DIRECTION_IN);
> > +	if (ret)
> 
> should be ret;  Thanks to 0-day for the report and fixed up.
> 

thanks for fixing it.

Regards,
angelo

> > +		return dev_err_probe(dev, PTR_ERR(rx_dma),
> > +				     "failed to setup offload RX DMA\n");
> > +
> > +	/* Use offload ops. */
> > +	indio_dev->setup_ops = &ad7606_offload_buffer_setup_ops;
> > +
> > +	st->offload_en = true;
> > +
> > +	return 0;
> > +}