linux-kernel - [PATCH 03/10] iio: adc: mcp3911: add support for buffers

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Message-Id: <20220623170844.2189814-3-marcus.folkesson@gmail.com>
Date:   Thu, 23 Jun 2022 19:08:37 +0200
From:   Marcus Folkesson <marcus.folkesson@...il.com>
To:     Marcus Folkesson <marcus.folkesson@...il.com>,
        Kent Gustavsson <kent@...oris.se>,
        Jonathan Cameron <jic23@...nel.org>,
        Lars-Peter Clausen <lars@...afoo.de>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>
Cc:     linux-iio@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH 03/10] iio: adc: mcp3911: add support for buffers

Add support for buffers to make the driver fit for more usecases.

Signed-off-by: Marcus Folkesson <marcus.folkesson@...il.com>
---
 drivers/iio/adc/mcp3911.c | 58 ++++++++++++++++++++++++++++++++++++++-
 1 file changed, 57 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/adc/mcp3911.c b/drivers/iio/adc/mcp3911.c
index 3d9e8ed10874..768cb0203f52 100644
--- a/drivers/iio/adc/mcp3911.c
+++ b/drivers/iio/adc/mcp3911.c
@@ -9,6 +9,10 @@
 #include <linux/delay.h>
 #include <linux/err.h>
 #include <linux/iio/iio.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/triggered_buffer.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/trigger.h>
 #include <linux/module.h>
 #include <linux/mod_devicetable.h>
 #include <linux/property.h>
@@ -54,6 +58,10 @@ struct mcp3911 {
 	struct regulator *vref;
 	struct clk *clki;
 	u32 dev_addr;
+	struct {
+		u32 channels[2];
+		s64 ts __aligned(8);
+	} scan;
 };
 
 static int mcp3911_read(struct mcp3911 *adc, u8 reg, u32 *val, u8 len)
@@ -187,16 +195,58 @@ static int mcp3911_write_raw(struct iio_dev *indio_dev,
 		.type = IIO_VOLTAGE,				\
 		.indexed = 1,					\
 		.channel = idx,					\
+		.scan_index = idx,				\
 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |	\
 			BIT(IIO_CHAN_INFO_OFFSET) |		\
 			BIT(IIO_CHAN_INFO_SCALE),		\
+		.scan_type = {					\
+			.sign = 's',				\
+			.realbits = 24,				\
+			.storagebits = 32,			\
+		},						\
 }
 
 static const struct iio_chan_spec mcp3911_channels[] = {
 	MCP3911_CHAN(0),
 	MCP3911_CHAN(1),
+	IIO_CHAN_SOFT_TIMESTAMP(2),
 };
 
+static irqreturn_t mcp3911_trigger_handler(int irq, void *p)
+{
+	struct iio_poll_func *pf = p;
+	struct iio_dev *indio_dev = pf->indio_dev;
+	struct mcp3911 *adc = iio_priv(indio_dev);
+	int scan_index;
+	int i = 0;
+	u32 val;
+
+	mutex_lock(&adc->lock);
+	for_each_set_bit(scan_index, indio_dev->active_scan_mask,
+			indio_dev->masklength) {
+		const struct iio_chan_spec *scan_chan =
+			&indio_dev->channels[scan_index];
+		int ret = mcp3911_read(adc,
+				MCP3911_CHANNEL(scan_chan->channel), &val, 3);
+
+		if (ret < 0) {
+			dev_warn(&adc->spi->dev,
+					"failed to get conversion data\n");
+			goto out;
+		}
+
+		adc->scan.channels[i] = val;
+		i++;
+	}
+	iio_push_to_buffers_with_timestamp(indio_dev, &adc->scan,
+			iio_get_time_ns(indio_dev));
+out:
+	mutex_unlock(&adc->lock);
+	iio_trigger_notify_done(indio_dev->trig);
+
+	return IRQ_HANDLED;
+}
+
 static const struct iio_info mcp3911_info = {
 	.read_raw = mcp3911_read_raw,
 	.write_raw = mcp3911_write_raw,
@@ -297,7 +347,7 @@ static int mcp3911_probe(struct spi_device *spi)
 		goto clk_disable;
 
 	indio_dev->name = spi_get_device_id(spi)->name;
-	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->modes = INDIO_DIRECT_MODE | INDIO_BUFFER_TRIGGERED;
 	indio_dev->info = &mcp3911_info;
 	spi_set_drvdata(spi, indio_dev);
 
@@ -306,6 +356,12 @@ static int mcp3911_probe(struct spi_device *spi)
 
 	mutex_init(&adc->lock);
 
+	ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev,
+			NULL,
+			mcp3911_trigger_handler, NULL);
+	if (ret)
+		goto clk_disable;
+
 	ret = devm_iio_device_register(&adc->spi->dev, indio_dev);
 	if (ret)
 		goto clk_disable;
-- 
2.36.1