iio: adc: stm32-adc: convert to device properties

Make the conversion to firmware agnostic device properties. As part of
the conversion the IIO inkern interface 'of_xlate()' is also converted to
'fwnode_xlate()'. The goal is to completely drop 'of_xlate' and hence OF
dependencies from IIO.
Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Tested-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Link: https://lore.kernel.org/r/20220715122903.332535-14-nuno.sa@analog.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/stm32-adc.c

@@ -21,11 +21,11 @@
 #include <linux/io.h>
 #include <linux/iopoll.h>
 #include <linux/module.h>
+#include <linux/mod_devicetable.h>
 #include <linux/nvmem-consumer.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
-#include <linux/of.h>
-#include <linux/of_device.h>
+#include <linux/property.h>
 
 #include "stm32-adc-core.h"
 
@@ -241,6 +241,7 @@ struct stm32_adc_cfg {
  * @chan_name:		channel name array
  * @num_diff:		number of differential channels
  * @int_ch:		internal channel indexes array
+ * @nsmps:		number of channels with optional sample time
  */
 struct stm32_adc {
 	struct stm32_adc_common	*common;
@@ -267,6 +268,7 @@ struct stm32_adc {
 	char			chan_name[STM32_ADC_CH_MAX][STM32_ADC_CH_SZ];
 	u32			num_diff;
 	int			int_ch[STM32_ADC_INT_CH_NB];
+	int			nsmps;
 };
 
 struct stm32_adc_diff_channel {
@@ -1520,8 +1522,8 @@ static int stm32_adc_update_scan_mode(struct iio_dev *indio_dev,
 	return ret;
 }
 
-static int stm32_adc_of_xlate(struct iio_dev *indio_dev,
-			      const struct of_phandle_args *iiospec)
+static int stm32_adc_fwnode_xlate(struct iio_dev *indio_dev,
+				  const struct fwnode_reference_args *iiospec)
 {
 	int i;
 
@@ -1575,7 +1577,7 @@ static const struct iio_info stm32_adc_iio_info = {
 	.hwfifo_set_watermark = stm32_adc_set_watermark,
 	.update_scan_mode = stm32_adc_update_scan_mode,
 	.debugfs_reg_access = stm32_adc_debugfs_reg_access,
-	.of_xlate = stm32_adc_of_xlate,
+	.fwnode_xlate = stm32_adc_fwnode_xlate,
 };
 
 static unsigned int stm32_adc_dma_residue(struct stm32_adc *adc)
@@ -1772,14 +1774,14 @@ static const struct iio_chan_spec_ext_info stm32_adc_ext_info[] = {
 	{},
 };
 
-static int stm32_adc_of_get_resolution(struct iio_dev *indio_dev)
+static int stm32_adc_fw_get_resolution(struct iio_dev *indio_dev)
 {
-	struct device_node *node = indio_dev->dev.of_node;
+	struct device *dev = &indio_dev->dev;
 	struct stm32_adc *adc = iio_priv(indio_dev);
 	unsigned int i;
 	u32 res;
 
-	if (of_property_read_u32(node, "assigned-resolution-bits", &res))
+	if (device_property_read_u32(dev, "assigned-resolution-bits", &res))
 		res = adc->cfg->adc_info->resolutions[0];
 
 	for (i = 0; i < adc->cfg->adc_info->num_res; i++)
@@ -1863,11 +1865,11 @@ static void stm32_adc_chan_init_one(struct iio_dev *indio_dev,
 
 static int stm32_adc_get_legacy_chan_count(struct iio_dev *indio_dev, struct stm32_adc *adc)
 {
-	struct device_node *node = indio_dev->dev.of_node;
+	struct device *dev = &indio_dev->dev;
 	const struct stm32_adc_info *adc_info = adc->cfg->adc_info;
 	int num_channels = 0, ret;
 
-	ret = of_property_count_u32_elems(node, "st,adc-channels");
+	ret = device_property_count_u32(dev, "st,adc-channels");
 	if (ret > adc_info->max_channels) {
 		dev_err(&indio_dev->dev, "Bad st,adc-channels?\n");
 		return -EINVAL;
@@ -1875,8 +1877,15 @@ static int stm32_adc_get_legacy_chan_count(struct iio_dev *indio_dev, struct stm
 		num_channels += ret;
 	}
 
-	ret = of_property_count_elems_of_size(node, "st,adc-diff-channels",
-					      sizeof(struct stm32_adc_diff_channel));
+	/*
+	 * each st,adc-diff-channels is a group of 2 u32 so we divide @ret
+	 * to get the *real* number of channels.
+	 */
+	ret = device_property_count_u32(dev, "st,adc-diff-channels");
+	if (ret < 0)
+		return ret;
+
+	ret /= (int)(sizeof(struct stm32_adc_diff_channel) / sizeof(u32));
 	if (ret > adc_info->max_channels) {
 		dev_err(&indio_dev->dev, "Bad st,adc-diff-channels?\n");
 		return -EINVAL;
@@ -1886,8 +1895,8 @@ static int stm32_adc_get_legacy_chan_count(struct iio_dev *indio_dev, struct stm
 	}
 
 	/* Optional sample time is provided either for each, or all channels */
-	ret = of_property_count_u32_elems(node, "st,min-sample-time-nsecs");
-	if (ret > 1 && ret != num_channels) {
+	adc->nsmps = device_property_count_u32(dev, "st,min-sample-time-nsecs");
+	if (adc->nsmps > 1 && adc->nsmps != num_channels) {
 		dev_err(&indio_dev->dev, "Invalid st,min-sample-time-nsecs\n");
 		return -EINVAL;
 	}
@@ -1897,20 +1906,19 @@ static int stm32_adc_get_legacy_chan_count(struct iio_dev *indio_dev, struct stm
 
 static int stm32_adc_legacy_chan_init(struct iio_dev *indio_dev,
 				      struct stm32_adc *adc,
-				      struct iio_chan_spec *channels)
+				      struct iio_chan_spec *channels,
+				      int nchans)
 {
-	struct device_node *node = indio_dev->dev.of_node;
 	const struct stm32_adc_info *adc_info = adc->cfg->adc_info;
 	struct stm32_adc_diff_channel diff[STM32_ADC_CH_MAX];
+	struct device *dev = &indio_dev->dev;
 	u32 num_diff = adc->num_diff;
 	int size = num_diff * sizeof(*diff) / sizeof(u32);
-	int scan_index = 0, val, ret, i;
-	struct property *prop;
-	const __be32 *cur;
-	u32 smp = 0;
+	int scan_index = 0, ret, i, c;
+	u32 smp = 0, smps[STM32_ADC_CH_MAX], chans[STM32_ADC_CH_MAX];
 
 	if (num_diff) {
-		ret = of_property_read_u32_array(node, "st,adc-diff-channels",
+		ret = device_property_read_u32_array(dev, "st,adc-diff-channels",
 						     (u32 *)diff, size);
 		if (ret) {
 			dev_err(&indio_dev->dev, "Failed to get diff channels %d\n", ret);
@@ -1932,32 +1940,47 @@ static int stm32_adc_legacy_chan_init(struct iio_dev *indio_dev,
 		}
 	}
 
-	of_property_for_each_u32(node, "st,adc-channels", prop, cur, val) {
-		if (val >= adc_info->max_channels) {
-			dev_err(&indio_dev->dev, "Invalid channel %d\n", val);
+	ret = device_property_read_u32_array(dev, "st,adc-channels", chans,
+					     nchans);
+	if (ret)
+		return ret;
+
+	for (c = 0; c < nchans; c++) {
+		if (chans[c] >= adc_info->max_channels) {
+			dev_err(&indio_dev->dev, "Invalid channel %d\n",
+				chans[c]);
 			return -EINVAL;
 		}
 
 		/* Channel can't be configured both as single-ended & diff */
 		for (i = 0; i < num_diff; i++) {
-			if (val == diff[i].vinp) {
-				dev_err(&indio_dev->dev, "channel %d misconfigured\n",	val);
+			if (chans[c] == diff[i].vinp) {
+				dev_err(&indio_dev->dev, "channel %d misconfigured\n",	chans[c]);
 				return -EINVAL;
 			}
 		}
-		stm32_adc_chan_init_one(indio_dev, &channels[scan_index], val,
-					0, scan_index, false);
+		stm32_adc_chan_init_one(indio_dev, &channels[scan_index],
+					chans[c], 0, scan_index, false);
 		scan_index++;
 	}
 
+	if (adc->nsmps > 0) {
+		ret = device_property_read_u32_array(dev, "st,min-sample-time-nsecs",
+						     smps, adc->nsmps);
+		if (ret)
+			return ret;
+	}
+
 	for (i = 0; i < scan_index; i++) {
 		/*
-		 * Using of_property_read_u32_index(), smp value will only be
-		 * modified if valid u32 value can be decoded. This allows to
-		 * get either no value, 1 shared value for all indexes, or one
-		 * value per channel.
+		 * This check is used with the above logic so that smp value
+		 * will only be modified if valid u32 value can be decoded. This
+		 * allows to get either no value, 1 shared value for all indexes,
+		 * or one value per channel. The point is to have the same
+		 * behavior as 'of_property_read_u32_index()'.
 		 */
-		of_property_read_u32_index(node, "st,min-sample-time-nsecs", i, &smp);
+		if (i < adc->nsmps)
+			smp = smps[i];
 
 		/* Prepare sampling time settings */
 		stm32_adc_smpr_init(adc, channels[i].channel, smp);
@@ -2005,22 +2028,21 @@ static int stm32_adc_generic_chan_init(struct iio_dev *indio_dev,
 				       struct stm32_adc *adc,
 				       struct iio_chan_spec *channels)
 {
-	struct device_node *node = indio_dev->dev.of_node;
 	const struct stm32_adc_info *adc_info = adc->cfg->adc_info;
-	struct device_node *child;
+	struct fwnode_handle *child;
 	const char *name;
 	int val, scan_index = 0, ret;
 	bool differential;
 	u32 vin[2];
 
-	for_each_available_child_of_node(node, child) {
-		ret = of_property_read_u32(child, "reg", &val);
+	device_for_each_child_node(&indio_dev->dev, child) {
+		ret = fwnode_property_read_u32(child, "reg", &val);
 		if (ret) {
 			dev_err(&indio_dev->dev, "Missing channel index %d\n", ret);
 			goto err;
 		}
 
-		ret = of_property_read_string(child, "label", &name);
+		ret = fwnode_property_read_string(child, "label", &name);
 		/* label is optional */
 		if (!ret) {
 			if (strlen(name) >= STM32_ADC_CH_SZ) {
@@ -2047,7 +2069,7 @@ static int stm32_adc_generic_chan_init(struct iio_dev *indio_dev,
 		}
 
 		differential = false;
-		ret = of_property_read_u32_array(child, "diff-channels", vin, 2);
+		ret = fwnode_property_read_u32_array(child, "diff-channels", vin, 2);
 		/* diff-channels is optional */
 		if (!ret) {
 			differential = true;
@@ -2064,7 +2086,7 @@ static int stm32_adc_generic_chan_init(struct iio_dev *indio_dev,
 		stm32_adc_chan_init_one(indio_dev, &channels[scan_index], val,
 					vin[1], scan_index, differential);
 
-		ret = of_property_read_u32(child, "st,min-sample-time-ns", &val);
+		ret = fwnode_property_read_u32(child, "st,min-sample-time-ns", &val);
 		/* st,min-sample-time-ns is optional */
 		if (!ret) {
 			stm32_adc_smpr_init(adc, channels[scan_index].channel, val);
@@ -2082,14 +2104,13 @@ static int stm32_adc_generic_chan_init(struct iio_dev *indio_dev,
 	return scan_index;
 
 err:
-	of_node_put(child);
+	fwnode_handle_put(child);
 
 	return ret;
 }
 
-static int stm32_adc_chan_of_init(struct iio_dev *indio_dev, bool timestamping)
+static int stm32_adc_chan_fw_init(struct iio_dev *indio_dev, bool timestamping)
 {
-	struct device_node *node = indio_dev->dev.of_node;
 	struct stm32_adc *adc = iio_priv(indio_dev);
 	const struct stm32_adc_info *adc_info = adc->cfg->adc_info;
 	struct iio_chan_spec *channels;
@@ -2099,7 +2120,7 @@ static int stm32_adc_chan_of_init(struct iio_dev *indio_dev, bool timestamping)
 	for (i = 0; i < STM32_ADC_INT_CH_NB; i++)
 		adc->int_ch[i] = STM32_ADC_INT_CH_NONE;
 
-	num_channels = of_get_available_child_count(node);
+	num_channels = device_get_child_node_count(&indio_dev->dev);
 	/* If no channels have been found, fallback to channels legacy properties. */
 	if (!num_channels) {
 		legacy = true;
@@ -2130,7 +2151,8 @@ static int stm32_adc_chan_of_init(struct iio_dev *indio_dev, bool timestamping)
 		return -ENOMEM;
 
 	if (legacy)
-		ret = stm32_adc_legacy_chan_init(indio_dev, adc, channels);
+		ret = stm32_adc_legacy_chan_init(indio_dev, adc, channels,
+						 num_channels);
 	else
 		ret = stm32_adc_generic_chan_init(indio_dev, adc, channels);
 	if (ret < 0)
@@ -2212,9 +2234,6 @@ static int stm32_adc_probe(struct platform_device *pdev)
 	bool timestamping = false;
 	int ret;
 
-	if (!pdev->dev.of_node)
-		return -ENODEV;
-
 	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*adc));
 	if (!indio_dev)
 		return -ENOMEM;
@@ -2223,17 +2242,16 @@ static int stm32_adc_probe(struct platform_device *pdev)
 	adc->common = dev_get_drvdata(pdev->dev.parent);
 	spin_lock_init(&adc->lock);
 	init_completion(&adc->completion);
-	adc->cfg = (const struct stm32_adc_cfg *)
-		of_match_device(dev->driver->of_match_table, dev)->data;
+	adc->cfg = device_get_match_data(dev);
 
 	indio_dev->name = dev_name(&pdev->dev);
-	indio_dev->dev.of_node = pdev->dev.of_node;
+	device_set_node(&indio_dev->dev, dev_fwnode(&pdev->dev));
 	indio_dev->info = &stm32_adc_iio_info;
 	indio_dev->modes = INDIO_DIRECT_MODE | INDIO_HARDWARE_TRIGGERED;
 
 	platform_set_drvdata(pdev, indio_dev);
 
-	ret = of_property_read_u32(pdev->dev.of_node, "reg", &adc->offset);
+	ret = device_property_read_u32(dev, "reg", &adc->offset);
 	if (ret != 0) {
 		dev_err(&pdev->dev, "missing reg property\n");
 		return -EINVAL;
@@ -2262,7 +2280,7 @@ static int stm32_adc_probe(struct platform_device *pdev)
 		}
 	}
 
-	ret = stm32_adc_of_get_resolution(indio_dev);
+	ret = stm32_adc_fw_get_resolution(indio_dev);
 	if (ret < 0)
 		return ret;
 
@@ -2279,7 +2297,7 @@ static int stm32_adc_probe(struct platform_device *pdev)
 		timestamping = true;
 	}
 
-	ret = stm32_adc_chan_of_init(indio_dev, timestamping);
+	ret = stm32_adc_chan_fw_init(indio_dev, timestamping);
 	if (ret < 0)
 		goto err_dma_disable;