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From:   Cristian Pop <cristian.pop@analog.com>
To:     <linux-iio@vger.kernel.org>, <linux-kernel@vger.kernel.org>
CC:     <jic23@kernel.org>, Cristian Pop <cristian.pop@analog.com>
Subject: [PATCH v6 3/4] iio: adc: ad7768-1: Add channel labels.
Date:   Mon, 21 Sep 2020 16:30:19 +0300
Message-ID: <20200921133020.62978-3-cristian.pop@analog.com>
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For better identification of the channels.

Signed-off-by: Cristian Pop <cristian.pop@analog.com>
---
Changes in v6:
 - Use static variable for labels
 drivers/iio/adc/ad7768-1.c | 41 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/drivers/iio/adc/ad7768-1.c b/drivers/iio/adc/ad7768-1.c
index 0e93b0766eb4..5c0cbee03230 100644
--- a/drivers/iio/adc/ad7768-1.c
+++ b/drivers/iio/adc/ad7768-1.c
@@ -161,6 +161,7 @@ struct ad7768_state {
 	struct completion completion;
 	struct iio_trigger *trig;
 	struct gpio_desc *gpio_sync_in;
+	const char *labels[ARRAY_SIZE(ad7768_channels)];
 	/*
 	 * DMA (thus cache coherency maintenance) requires the
 	 * transfer buffers to live in their own cache lines.
@@ -407,6 +408,14 @@ static int ad7768_write_raw(struct iio_dev *indio_dev,
 	}
 }
 
+static int ad7768_read_label(struct iio_dev *indio_dev,
+	const struct iio_chan_spec *chan, char *label)
+{
+	struct ad7768_state *st = iio_priv(indio_dev);
+
+	return sprintf(label, "%s\n", st->labels[chan->channel]);
+}
+
 static struct attribute *ad7768_attributes[] = {
 	&iio_dev_attr_sampling_frequency_available.dev_attr.attr,
 	NULL
@@ -420,6 +429,7 @@ static const struct iio_info ad7768_info = {
 	.attrs = &ad7768_group,
 	.read_raw = &ad7768_read_raw,
 	.write_raw = &ad7768_write_raw,
+	.read_label = ad7768_read_label,
 	.debugfs_reg_access = &ad7768_reg_access,
 };
 
@@ -532,6 +542,33 @@ static void ad7768_clk_disable(void *data)
 	clk_disable_unprepare(st->mclk);
 }
 
+static int ad7768_set_channel_label(struct iio_dev *indio_dev,
+						int num_channels)
+{
+	struct ad7768_state *st = iio_priv(indio_dev);
+	struct device *device = indio_dev->dev.parent;
+	struct fwnode_handle *fwnode;
+	struct fwnode_handle *child;
+	const char *label;
+	int crt_ch = 0;
+
+	fwnode = dev_fwnode(device);
+	fwnode_for_each_child_node(fwnode, child) {
+		if (fwnode_property_read_u32(child, "reg", &crt_ch))
+			continue;
+
+		if (crt_ch >= num_channels)
+			continue;
+
+		if (fwnode_property_read_string(child, "label", &label))
+			continue;
+
+		st->labels[crt_ch] = label;
+	}
+
+	return 0;
+}
+
 static int ad7768_probe(struct spi_device *spi)
 {
 	struct ad7768_state *st;
@@ -604,6 +641,10 @@ static int ad7768_probe(struct spi_device *spi)
 
 	init_completion(&st->completion);
 
+	ret = ad7768_set_channel_label(indio_dev, ARRAY_SIZE(ad7768_channels));
+	if (ret)
+		return ret;
+
 	ret = devm_request_irq(&spi->dev, spi->irq,
 			       &ad7768_interrupt,
 			       IRQF_TRIGGER_RISING | IRQF_ONESHOT,
-- 
2.17.1