[PATCH v9 4/6] iio: adc: ltc2378: Enable triggered buffer data capture

Marcelo Schmitt <[email protected]>
Newsgroups org.kernel.vger.linux-iio,org.kernel.vger.linux-devicetree,org.kernel.vger.linux-kernel
Message-ID <6a543eee39b1aa8cee6a2455bb84e483b425746b.1785186980.git.marcelo.schmitt@analog.com> 
Enable users to run triggered data captures with LTC2378 and similar ADCs.

Reviewed-by: Andy Shevchenko <[email protected]>
Reviewed-by: David Lechner <[email protected]>
Signed-off-by: Marcelo Schmitt <[email protected]>
---
Change log v8 -> v9:
No changes in v9.

 drivers/iio/adc/Kconfig   |  1 +
 drivers/iio/adc/ltc2378.c | 73 +++++++++++++++++++++++++++------------
 2 files changed, 52 insertions(+), 22 deletions(-)

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 96df8453b826..6cf67f7a6eed 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -952,6 +952,7 @@ config LTC2378
 	select IIO_BUFFER
 	select IIO_BUFFER_DMA
 	select IIO_BUFFER_DMAENGINE
+	select IIO_TRIGGERED_BUFFER
 	select SPI_OFFLOAD
 	select SPI_OFFLOAD_TRIGGER_PWM
 	help
diff --git a/drivers/iio/adc/ltc2378.c b/drivers/iio/adc/ltc2378.c
index 48380a2d7dc6..146eaadbeb6c 100644
--- a/drivers/iio/adc/ltc2378.c
+++ b/drivers/iio/adc/ltc2378.c
@@ -6,6 +6,7 @@
  * Author: Marcelo Schmitt <[email protected]>
  */
 
+#include <linux/array_size.h>
 #include <linux/bitops.h>
 #include <linux/bits.h>
 #include <linux/byteorder/generic.h>
@@ -32,6 +33,8 @@
 #include <linux/iio/buffer.h>
 #include <linux/iio/buffer-dmaengine.h>
 #include <linux/iio/iio.h>
+#include <linux/iio/triggered_buffer.h>
+#include <linux/iio/trigger_consumer.h>
 #include <linux/iio/types.h>
 
 #define LTC2378_TDSDOBUSYL_NS		5
@@ -104,7 +107,7 @@
 
 struct ltc2378_chip_info {
 	const char *name;
-	struct iio_chan_spec chan;
+	struct iio_chan_spec chan[2]; /* 1 physical chan + 1 timestamp chan */
 	struct iio_chan_spec offload_chan;
 	unsigned int max_sample_rate_Hz;
 	unsigned int tconv_ns;
@@ -144,7 +147,7 @@ struct ltc2378_state {
 
 static const struct ltc2378_chip_info ltc2364_16_chip_info = {
 	.name = "ltc2364-16",
-	.chan = LTC2378_PSEUDO_DIFF_CHANNEL(16),
+	.chan = { LTC2378_PSEUDO_DIFF_CHANNEL(16), IIO_CHAN_SOFT_TIMESTAMP(1) },
 	.offload_chan = LTC2378_OFFLOAD_PSEUDO_DIFF_CHANNEL(16),
 	.max_sample_rate_Hz = 250 * HZ_PER_KHZ,
 	.tconv_ns = 3000,
@@ -152,7 +155,7 @@ static const struct ltc2378_chip_info ltc2364_16_chip_info = {
 
 static const struct ltc2378_chip_info ltc2364_18_chip_info = {
 	.name = "ltc2364-18",
-	.chan = LTC2378_PSEUDO_DIFF_CHANNEL(18),
+	.chan = { LTC2378_PSEUDO_DIFF_CHANNEL(18), IIO_CHAN_SOFT_TIMESTAMP(1) },
 	.offload_chan = LTC2378_OFFLOAD_PSEUDO_DIFF_CHANNEL(18),
 	.max_sample_rate_Hz = 250 * HZ_PER_KHZ,
 	.tconv_ns = 3000,
@@ -160,7 +163,7 @@ static const struct ltc2378_chip_info ltc2364_18_chip_info = {
 
 static const struct ltc2378_chip_info ltc2367_16_chip_info = {
 	.name = "ltc2367-16",
-	.chan = LTC2378_PSEUDO_DIFF_CHANNEL(16),
+	.chan = { LTC2378_PSEUDO_DIFF_CHANNEL(16), IIO_CHAN_SOFT_TIMESTAMP(1) },
 	.offload_chan = LTC2378_OFFLOAD_PSEUDO_DIFF_CHANNEL(16),
 	.max_sample_rate_Hz = 500 * HZ_PER_KHZ,
 	.tconv_ns = 1500,
@@ -168,7 +171,7 @@ static const struct ltc2378_chip_info ltc2367_16_chip_info = {
 
 static const struct ltc2378_chip_info ltc2367_18_chip_info = {
 	.name = "ltc2367-18",
-	.chan = LTC2378_PSEUDO_DIFF_CHANNEL(18),
+	.chan = { LTC2378_PSEUDO_DIFF_CHANNEL(18), IIO_CHAN_SOFT_TIMESTAMP(1) },
 	.offload_chan = LTC2378_OFFLOAD_PSEUDO_DIFF_CHANNEL(18),
 	.max_sample_rate_Hz = 500 * HZ_PER_KHZ,
 	.tconv_ns = 1500,
@@ -176,7 +179,7 @@ static const struct ltc2378_chip_info ltc2367_18_chip_info = {
 
 static const struct ltc2378_chip_info ltc2368_16_chip_info = {
 	.name = "ltc2368-16",
-	.chan = LTC2378_PSEUDO_DIFF_CHANNEL(16),
+	.chan = { LTC2378_PSEUDO_DIFF_CHANNEL(16), IIO_CHAN_SOFT_TIMESTAMP(1) },
 	.offload_chan = LTC2378_OFFLOAD_PSEUDO_DIFF_CHANNEL(16),
 	.max_sample_rate_Hz = 1 * HZ_PER_MHZ,
 	.tconv_ns = 527,
@@ -184,7 +187,7 @@ static const struct ltc2378_chip_info ltc2368_16_chip_info = {
 
 static const struct ltc2378_chip_info ltc2368_18_chip_info = {
 	.name = "ltc2368-18",
-	.chan = LTC2378_PSEUDO_DIFF_CHANNEL(18),
+	.chan = { LTC2378_PSEUDO_DIFF_CHANNEL(18), IIO_CHAN_SOFT_TIMESTAMP(1) },
 	.offload_chan = LTC2378_OFFLOAD_PSEUDO_DIFF_CHANNEL(18),
 	.max_sample_rate_Hz = 1 * HZ_PER_MHZ,
 	.tconv_ns = 527,
@@ -192,7 +195,7 @@ static const struct ltc2378_chip_info ltc2368_18_chip_info = {
 
 static const struct ltc2378_chip_info ltc2369_18_chip_info = {
 	.name = "ltc2369-18",
-	.chan = LTC2378_PSEUDO_DIFF_CHANNEL(18),
+	.chan = { LTC2378_PSEUDO_DIFF_CHANNEL(18), IIO_CHAN_SOFT_TIMESTAMP(1) },
 	.offload_chan = LTC2378_OFFLOAD_PSEUDO_DIFF_CHANNEL(18),
 	.max_sample_rate_Hz = 1600 * HZ_PER_KHZ,
 	.tconv_ns = 412,
@@ -200,7 +203,7 @@ static const struct ltc2378_chip_info ltc2369_18_chip_info = {
 
 static const struct ltc2378_chip_info ltc2370_16_chip_info = {
 	.name = "ltc2370-16",
-	.chan = LTC2378_PSEUDO_DIFF_CHANNEL(16),
+	.chan = { LTC2378_PSEUDO_DIFF_CHANNEL(16), IIO_CHAN_SOFT_TIMESTAMP(1) },
 	.offload_chan = LTC2378_OFFLOAD_PSEUDO_DIFF_CHANNEL(16),
 	.max_sample_rate_Hz = 2 * HZ_PER_MHZ,
 	.tconv_ns = 322,
@@ -208,7 +211,7 @@ static const struct ltc2378_chip_info ltc2370_16_chip_info = {
 
 static const struct ltc2378_chip_info ltc2376_16_chip_info = {
 	.name = "ltc2376-16",
-	.chan = LTC2378_DIFF_CHANNEL(16),
+	.chan = { LTC2378_DIFF_CHANNEL(16), IIO_CHAN_SOFT_TIMESTAMP(1) },
 	.offload_chan = LTC2378_OFFLOAD_DIFF_CHANNEL(16),
 	.max_sample_rate_Hz = 250 * HZ_PER_KHZ,
 	.tconv_ns = 3000,
@@ -216,7 +219,7 @@ static const struct ltc2378_chip_info ltc2376_16_chip_info = {
 
 static const struct ltc2378_chip_info ltc2376_18_chip_info = {
 	.name = "ltc2376-18",
-	.chan = LTC2378_DIFF_CHANNEL(18),
+	.chan = { LTC2378_DIFF_CHANNEL(18), IIO_CHAN_SOFT_TIMESTAMP(1) },
 	.offload_chan = LTC2378_OFFLOAD_DIFF_CHANNEL(18),
 	.max_sample_rate_Hz = 250 * HZ_PER_KHZ,
 	.tconv_ns = 3000,
@@ -224,7 +227,7 @@ static const struct ltc2378_chip_info ltc2376_18_chip_info = {
 
 static const struct ltc2378_chip_info ltc2376_20_chip_info = {
 	.name = "ltc2376-20",
-	.chan = LTC2378_DIFF_CHANNEL(20),
+	.chan = { LTC2378_DIFF_CHANNEL(20), IIO_CHAN_SOFT_TIMESTAMP(1) },
 	.offload_chan = LTC2378_OFFLOAD_DIFF_CHANNEL(20),
 	.max_sample_rate_Hz = 250 * HZ_PER_KHZ,
 	.tconv_ns = 3000,
@@ -232,7 +235,7 @@ static const struct ltc2378_chip_info ltc2376_20_chip_info = {
 
 static const struct ltc2378_chip_info ltc2377_16_chip_info = {
 	.name = "ltc2377-16",
-	.chan = LTC2378_DIFF_CHANNEL(16),
+	.chan = { LTC2378_DIFF_CHANNEL(16), IIO_CHAN_SOFT_TIMESTAMP(1) },
 	.offload_chan = LTC2378_OFFLOAD_DIFF_CHANNEL(16),
 	.max_sample_rate_Hz = 500 * HZ_PER_KHZ,
 	.tconv_ns = 1500,
@@ -240,7 +243,7 @@ static const struct ltc2378_chip_info ltc2377_16_chip_info = {
 
 static const struct ltc2378_chip_info ltc2377_18_chip_info = {
 	.name = "ltc2377-18",
-	.chan = LTC2378_DIFF_CHANNEL(18),
+	.chan = { LTC2378_DIFF_CHANNEL(18), IIO_CHAN_SOFT_TIMESTAMP(1) },
 	.offload_chan = LTC2378_OFFLOAD_DIFF_CHANNEL(18),
 	.max_sample_rate_Hz = 500 * HZ_PER_KHZ,
 	.tconv_ns = 1500,
@@ -248,7 +251,7 @@ static const struct ltc2378_chip_info ltc2377_18_chip_info = {
 
 static const struct ltc2378_chip_info ltc2377_20_chip_info = {
 	.name = "ltc2377-20",
-	.chan = LTC2378_DIFF_CHANNEL(20),
+	.chan = { LTC2378_DIFF_CHANNEL(20), IIO_CHAN_SOFT_TIMESTAMP(1) },
 	.offload_chan = LTC2378_OFFLOAD_DIFF_CHANNEL(20),
 	.max_sample_rate_Hz = 500 * HZ_PER_KHZ,
 	.tconv_ns = 1500,
@@ -256,7 +259,7 @@ static const struct ltc2378_chip_info ltc2377_20_chip_info = {
 
 static const struct ltc2378_chip_info ltc2378_16_chip_info = {
 	.name = "ltc2378-16",
-	.chan = LTC2378_DIFF_CHANNEL(16),
+	.chan = { LTC2378_DIFF_CHANNEL(16), IIO_CHAN_SOFT_TIMESTAMP(1) },
 	.offload_chan = LTC2378_OFFLOAD_DIFF_CHANNEL(16),
 	.max_sample_rate_Hz = 1 * HZ_PER_MHZ,
 	.tconv_ns = 527,
@@ -264,7 +267,7 @@ static const struct ltc2378_chip_info ltc2378_16_chip_info = {
 
 static const struct ltc2378_chip_info ltc2378_18_chip_info = {
 	.name = "ltc2378-18",
-	.chan = LTC2378_DIFF_CHANNEL(18),
+	.chan = { LTC2378_DIFF_CHANNEL(18), IIO_CHAN_SOFT_TIMESTAMP(1) },
 	.offload_chan = LTC2378_OFFLOAD_DIFF_CHANNEL(18),
 	.max_sample_rate_Hz = 1 * HZ_PER_MHZ,
 	.tconv_ns = 527,
@@ -272,7 +275,7 @@ static const struct ltc2378_chip_info ltc2378_18_chip_info = {
 
 static const struct ltc2378_chip_info ltc2378_20_chip_info = {
 	.name = "ltc2378-20",
-	.chan = LTC2378_DIFF_CHANNEL(20),
+	.chan = { LTC2378_DIFF_CHANNEL(20), IIO_CHAN_SOFT_TIMESTAMP(1) },
 	.offload_chan = LTC2378_OFFLOAD_DIFF_CHANNEL(20),
 	.max_sample_rate_Hz = 1 * HZ_PER_MHZ,
 	.tconv_ns = 675,
@@ -280,7 +283,7 @@ static const struct ltc2378_chip_info ltc2378_20_chip_info = {
 
 static const struct ltc2378_chip_info ltc2379_18_chip_info = {
 	.name = "ltc2379-18",
-	.chan = LTC2378_DIFF_CHANNEL(18),
+	.chan = { LTC2378_DIFF_CHANNEL(18), IIO_CHAN_SOFT_TIMESTAMP(1) },
 	.offload_chan = LTC2378_OFFLOAD_DIFF_CHANNEL(18),
 	.max_sample_rate_Hz = 1600 * HZ_PER_KHZ,
 	.tconv_ns = 412,
@@ -288,7 +291,7 @@ static const struct ltc2378_chip_info ltc2379_18_chip_info = {
 
 static const struct ltc2378_chip_info ltc2380_16_chip_info = {
 	.name = "ltc2380-16",
-	.chan = LTC2378_DIFF_CHANNEL(16),
+	.chan = { LTC2378_DIFF_CHANNEL(16), IIO_CHAN_SOFT_TIMESTAMP(1) },
 	.offload_chan = LTC2378_OFFLOAD_DIFF_CHANNEL(16),
 	.max_sample_rate_Hz = 2 * HZ_PER_MHZ,
 	.tconv_ns = 322,
@@ -307,6 +310,25 @@ static int ltc2378_convert_and_acquire(struct ltc2378_state *st)
 	return ret;
 }
 
+static irqreturn_t ltc2378_trigger_handler(int irq, void *p)
+{
+	struct iio_poll_func *pf = p;
+	struct iio_dev *indio_dev = pf->indio_dev;
+	struct ltc2378_state *st = iio_priv(indio_dev);
+	int ret;
+
+	ret = ltc2378_convert_and_acquire(st);
+	if (ret < 0)
+		goto err_out;
+
+	iio_push_to_buffers_with_ts(indio_dev, &st->scan, sizeof(st->scan),
+				    pf->timestamp);
+
+err_out:
+	iio_trigger_notify_done(indio_dev->trig);
+	return IRQ_HANDLED;
+}
+
 static int ltc2378_channel_single_read(const struct iio_chan_spec *chan,
 				       struct ltc2378_state *st, int *val)
 {
@@ -671,8 +693,15 @@ static int ltc2378_probe(struct spi_device *spi)
 	/* Fall back to low speed usage when no SPI offload is available. */
 	if (ret == -ENODEV) {
 		indio_dev->info = &ltc2378_iio_info;
-		indio_dev->channels = &st->info->chan;
-		indio_dev->num_channels = 1;
+		indio_dev->channels = st->info->chan;
+		indio_dev->num_channels = ARRAY_SIZE(st->info->chan);
+
+		ret = devm_iio_triggered_buffer_setup(dev, indio_dev,
+						      iio_pollfunc_store_time,
+						      ltc2378_trigger_handler,
+						      NULL);
+		if (ret)
+			return ret;
 	} else if (ret) {
 		return dev_err_probe(dev, ret, "failed to get offload\n");
 	} else {
-- 
2.53.0
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