[PATCH v8 00/10] Support ROHM BD79124 ADC

[PATCH v8 00/10] Support ROHM BD79124 ADC

[Matti Vaittinen]

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Support ROHM BD79124 ADC.

This series adds also couple of IIO ADC helper functions for parsing the
channel information from the device tree. There are also new helpers
included for iterating and counting firmware child nodes with a specific
name.

Series does also convert couple of drivers to use these helpers. The
rzg2l_adc and the sun20i-gpadc are converted to use the new ADC helper.

The gianfar driver under net and the thp7312 under media/i2c are added as
first users of the newly added "named child node" -helpers.

There has been some discussion about how useful these ADC helpers are,
and whether they should support also differential and single ended channel
configurations. This version does not include support for those - with the
benefit of reduced complexity and easier to use API.

NOTE: Patches 4,5,9 and 10 are untested as I lack of relevant HW.
They have been compile tested only.

The ROHM BD79124 ADC itself is quite usual stuff. 12-bit, 8-channel ADC
with threshold monitoring.

Except that:
 - each ADC input pin can be configured as a general purpose output.
 - manually starting an ADC conversion and reading the result would
   require the I2C _master_ to do clock stretching(!) for the duration
   of the conversion... Let's just say this is not well supported.
 - IC supports 'autonomous measurement mode' and storing latest results
   to the result registers. This mode is used by the driver due to the
   "peculiar" I2C when doing manual reads.

Furthermore, the ADC uses this continuous autonomous measuring,
and the IC keeps producing new 'out of window' IRQs if measurements are
out of window - the driver disables the event for 1 seconds when sending
it to user. This prevents generating storm of events

Revision history:

v7 => v8:
  property helpers:
    - Fix the example in fwnode_get_named_child_node_count() documentation
      to use the fwnode_get_named_child_node_count() and not the
      device_get_named_child_node_count()
    - Fix the rest of the new macro's indentiations
  adc helpers:
    - Treat 0 ADC channels as an error in
      devm_iio_adc_device_alloc_chaninfo_se().
  rzg2l_adc / sun20i-gpadc:
    - Drop zero channels check from the ADC drivers using
      devm_iio_adc_device_alloc_chaninfo_se()
  BD79124:
    - Use unsigned for regmap values
    - Commit message fine tuning
    - Check devm_mutex_init() return value
    - Handle 'ALL pins as ADC or GPO' cleanly in BD79124 driver
    - BD79124 styling / typofixes

v6 => v7:
 - Inline device_get_named_child_node_count()
 - Fix kernel-doc for fwnode_get_named_child_node_count()
 - Minor styling fixes
 More accurate changelog in individual patches.

v5 => v6:
 - Drop applied patch
 - Add *_for_each_named_child_* iterators
 - Add a patch converting the thp7312 driver to use the new helper
 - Styling and minor things pointed by reviewers

v4 => v5: Fixes as per various review comments. Most notably:
 - Drop the patch making the TI's ADC driver to respect device tree.
 - Add (RFC) patch converting gianfar driver to use new name child-node
   counting API as suggested by Andy.
 - Add fwnode_get_child_node_count_named() as suggested by Rob.
 - rebase to v6.14-rc5
 More accurate changelog in individual patches.

v3 => v4:
 - Drop the ADC helper support for differential channels
 - Drop the ADC helper for getting only channel IDs by fwnode.
 - "Promote" the function counting the number of child nodes with a
   specific name to the property.h (As suggested by Jonathan).
 - Add ADC helpers to a namespace.
 - Rebase on v6.14-rc3
 - More minor changes described in individual patches.

v2 => v3:
 - Restrict BD79124 channel numbers as suggested by Conor and add
   Conor's Reviewed-by tag.
 - Support differential and single-ended inputs
 - Convert couple of existing drivers to use the added ADC helpers
 - Minor fixes based on reviews
Link to v2:
https://lore.kernel.org/all/cover.1738761899.git.mazziesaccount@gmail.com/

RFC v1 => v2:
 - Drop MFD and pinmux.
 - Automatically re-enable events after 1 second.
 - Export fwnode parsing helpers for finding the ADC channels.

---

Matti Vaittinen (10):
  dt-bindings: ROHM BD79124 ADC/GPO
  property: Add functions to iterate named child
  iio: adc: add helpers for parsing ADC nodes
  iio: adc: rzg2l_adc: Use adc-helpers
  iio: adc: sun20i-gpadc: Use adc-helpers
  iio: adc: Support ROHM BD79124 ADC
  MAINTAINERS: Add IIO ADC helpers
  MAINTAINERS: Add ROHM BD79124 ADC/GPO
  net: gianfar: Use device_get_child_node_count_named()
  media: thp7312: Use helper for iterating named child nodes

 .../bindings/iio/adc/rohm,bd79124.yaml        |  114 ++
 MAINTAINERS                                   |   12 +
 drivers/base/property.c                       |   27 +
 drivers/iio/adc/Kconfig                       |   17 +
 drivers/iio/adc/Makefile                      |    3 +
 drivers/iio/adc/industrialio-adc.c            |   82 ++
 drivers/iio/adc/rohm-bd79124.c                | 1138 +++++++++++++++++
 drivers/iio/adc/rzg2l_adc.c                   |   39 +-
 drivers/iio/adc/sun20i-gpadc-iio.c            |   39 +-
 drivers/media/i2c/thp7312.c                   |    8 +-
 drivers/net/ethernet/freescale/gianfar.c      |   17 +-
 include/linux/iio/adc-helpers.h               |   27 +
 include/linux/property.h                      |   24 +
 13 files changed, 1481 insertions(+), 66 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/iio/adc/rohm,bd79124.yaml
 create mode 100644 drivers/iio/adc/industrialio-adc.c
 create mode 100644 drivers/iio/adc/rohm-bd79124.c
 create mode 100644 include/linux/iio/adc-helpers.h


base-commit: 7eb172143d5508b4da468ed59ee857c6e5e01da6
-- 
2.48.1


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[PATCH v8 01/10] dt-bindings: ROHM BD79124 ADC/GPO

[Matti Vaittinen]

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Add binding document for the ROHM BD79124 ADC / GPO.

ROHM BD79124 is a 8-channel, 12-bit ADC. The input pins can also be used
as general purpose outputs.

Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
---
Revision history:
v3 =>
 - No changes
v2 => v3:
 - Restrict channel numbers to 0-7 as suggested by Conor
RFC v1 => v2:
 - drop MFD and represent directly as ADC
 - drop pinmux and treat all non ADC channel pins as GPOs
---
 .../bindings/iio/adc/rohm,bd79124.yaml        | 114 ++++++++++++++++++
 1 file changed, 114 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/adc/rohm,bd79124.yaml

diff --git a/Documentation/devicetree/bindings/iio/adc/rohm,bd79124.yaml b/Documentation/devicetree/bindings/iio/adc/rohm,bd79124.yaml
new file mode 100644
index 000000000000..503285823376
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/adc/rohm,bd79124.yaml
@@ -0,0 +1,114 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/adc/rohm,bd79124.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: ROHM BD79124 ADC/GPO
+
+maintainers:
+  - Matti Vaittinen <mazziesaccount@gmail.com>
+
+description: |
+  The ROHM BD79124 is a 12-bit, 8-channel, SAR ADC. The ADC supports
+  an automatic measurement mode, with an alarm interrupt for out-of-window
+  measurements. ADC input pins can be also configured as general purpose
+  outputs.
+
+properties:
+  compatible:
+    const: rohm,bd79124
+
+  reg:
+    description:
+      I2C slave address.
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  gpio-controller: true
+
+  "#gpio-cells":
+    const: 1
+    description:
+      The pin number.
+
+  vdd-supply: true
+
+  iovdd-supply: true
+
+  "#address-cells":
+    const: 1
+
+  "#size-cells":
+    const: 0
+
+patternProperties:
+  "^channel@[0-7]+$":
+    type: object
+    $ref: /schemas/iio/adc/adc.yaml#
+    description: Represents ADC channel.
+
+    properties:
+      reg:
+        description: AIN pin number
+        minimum: 0
+        maximum: 7
+
+    required:
+      - reg
+
+    additionalProperties: false
+
+required:
+  - compatible
+  - reg
+  - iovdd-supply
+  - vdd-supply
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+    #include <dt-bindings/leds/common.h>
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+        adc: adc@10 {
+            compatible = "rohm,bd79124";
+            reg = <0x10>;
+
+            interrupt-parent = <&gpio1>;
+            interrupts = <29 8>;
+
+            vdd-supply = <&dummyreg>;
+            iovdd-supply = <&dummyreg>;
+
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            channel@0 {
+                reg = <0>;
+            };
+            channel@1 {
+                reg = <1>;
+            };
+            channel@2 {
+                reg = <2>;
+            };
+            channel@3 {
+                reg = <3>;
+            };
+            channel@4 {
+                reg = <4>;
+            };
+            channel@5 {
+                reg = <5>;
+            };
+            channel@6 {
+                reg = <6>;
+            };
+        };
+    };
-- 
2.48.1


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[PATCH v8 02/10] property: Add functions to iterate named child

[Matti Vaittinen]

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There are a few use-cases where child nodes with a specific name need to
be parsed. Code like:

fwnode_for_each_child_node()
	if (fwnode_name_eq())
		...

can be found from a various drivers/subsystems. Adding a macro for this
can simplify things a bit.

In a few cases the data from the found nodes is later added to an array,
which is allocated based on the number of found nodes. One example of
such use is the IIO subsystem's ADC channel nodes, where the relevant
nodes are named as channel[@N].

Add helpers for iterating and counting device's sub-nodes with certain
name instead of open-coding this in every user.

Suggested-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Marcelo Schmitt <marcelo.schmitt1@gmail.com>
---
Revision history:
v7 => v8:
 - Fix the example in fwnode_get_named_child_node_count() documentation
   to use the fwnode_get_named_child_node_count() and not the
   device_get_named_child_node_count()
 - Fix the rest of the new macro's indentiations
v6 => v7:
 - Improve kerneldoc
 - Inline device_get_named_child_node_count() and change it to call
   fwnode_get_named_child_node_count() inside
 - Fix indentiation of the new macros
v5 => v6:
 - Add helpers to also iterate through the nodes.
v4 => v5:
 - Use given name instead of string 'channel' when counting the nodes
 - Add also fwnode_get_child_node_count_named() as suggested by Rob.
v3 => v4:
 - New patch as suggested by Jonathan, see discussion in:
https://lore.kernel.org/lkml/20250223161338.5c896280@jic23-huawei/
---
 drivers/base/property.c  | 27 +++++++++++++++++++++++++++
 include/linux/property.h | 24 ++++++++++++++++++++++++
 2 files changed, 51 insertions(+)

diff --git a/drivers/base/property.c b/drivers/base/property.c
index c1392743df9c..f42f32ff45fc 100644
--- a/drivers/base/property.c
+++ b/drivers/base/property.c
@@ -945,6 +945,33 @@ unsigned int device_get_child_node_count(const struct device *dev)
 }
 EXPORT_SYMBOL_GPL(device_get_child_node_count);
 
+/**
+ * fwnode_get_named_child_node_count - number of child nodes with given name
+ * @fwnode: Node which child nodes are counted.
+ * @name: String to match child node name against.
+ *
+ * Scan child nodes and count all the nodes with a specific name. Potential
+ * 'number' -ending after the 'at sign' for scanned names is ignored.
+ * E.g.::
+ *   fwnode_get_named_child_node_count(fwnode, "channel");
+ * would match all the nodes::
+ *   channel { }, channel@0 {}, channel@0xabba {}...
+ *
+ * Return: the number of child nodes with a matching name for a given device.
+ */
+unsigned int fwnode_get_named_child_node_count(const struct fwnode_handle *fwnode,
+					       const char *name)
+{
+	struct fwnode_handle *child;
+	unsigned int count = 0;
+
+	fwnode_for_each_named_child_node(fwnode, child, name)
+		count++;
+
+	return count;
+}
+EXPORT_SYMBOL_GPL(fwnode_get_named_child_node_count);
+
 bool device_dma_supported(const struct device *dev)
 {
 	return fwnode_call_bool_op(dev_fwnode(dev), device_dma_supported);
diff --git a/include/linux/property.h b/include/linux/property.h
index e214ecd241eb..a1856e6b714c 100644
--- a/include/linux/property.h
+++ b/include/linux/property.h
@@ -167,10 +167,18 @@ struct fwnode_handle *fwnode_get_next_available_child_node(
 	for (child = fwnode_get_next_child_node(fwnode, NULL); child;	\
 	     child = fwnode_get_next_child_node(fwnode, child))
 
+#define fwnode_for_each_named_child_node(fwnode, child, name)		\
+	fwnode_for_each_child_node(fwnode, child)			\
+		if (!fwnode_name_eq(child, name)) { } else
+
 #define fwnode_for_each_available_child_node(fwnode, child)		       \
 	for (child = fwnode_get_next_available_child_node(fwnode, NULL); child;\
 	     child = fwnode_get_next_available_child_node(fwnode, child))
 
+#define fwnode_for_each_available_named_child_node(fwnode, child, name)	\
+	fwnode_for_each_available_child_node(fwnode, child)		\
+		if (!fwnode_name_eq(child, name)) { } else
+
 struct fwnode_handle *device_get_next_child_node(const struct device *dev,
 						 struct fwnode_handle *child);
 
@@ -178,11 +186,19 @@ struct fwnode_handle *device_get_next_child_node(const struct device *dev,
 	for (child = device_get_next_child_node(dev, NULL); child;	\
 	     child = device_get_next_child_node(dev, child))
 
+#define device_for_each_named_child_node(dev, child, name)		\
+	device_for_each_child_node(dev, child)				\
+		if (!fwnode_name_eq(child, name)) { } else
+
 #define device_for_each_child_node_scoped(dev, child)			\
 	for (struct fwnode_handle *child __free(fwnode_handle) =	\
 		device_get_next_child_node(dev, NULL);			\
 	     child; child = device_get_next_child_node(dev, child))
 
+#define device_for_each_named_child_node_scoped(dev, child, name)	\
+	device_for_each_child_node_scoped(dev, child)			\
+		if (!fwnode_name_eq(child, name)) { } else
+
 struct fwnode_handle *fwnode_get_named_child_node(const struct fwnode_handle *fwnode,
 						  const char *childname);
 struct fwnode_handle *device_get_named_child_node(const struct device *dev,
@@ -210,6 +226,14 @@ int fwnode_irq_get_byname(const struct fwnode_handle *fwnode, const char *name);
 
 unsigned int device_get_child_node_count(const struct device *dev);
 
+unsigned int fwnode_get_named_child_node_count(const struct fwnode_handle *fwnode,
+					       const char *name);
+static inline unsigned int device_get_named_child_node_count(const struct device *dev,
+							     const char *name)
+{
+	return fwnode_get_named_child_node_count(dev_fwnode(dev), name);
+}
+
 static inline int device_property_read_u8(const struct device *dev,
 					  const char *propname, u8 *val)
 {
-- 
2.48.1


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[PATCH v8 03/10] iio: adc: add helpers for parsing ADC nodes

[Matti Vaittinen]

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There are ADC ICs which may have some of the AIN pins usable for other
functions. These ICs may have some of the AIN pins wired so that they
should not be used for ADC.

(Preferred?) way for marking pins which can be used as ADC inputs is to
add corresponding channels@N nodes in the device tree as described in
the ADC binding yaml.

Add couple of helper functions which can be used to retrieve the channel
information from the device node.

Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>

---
Revision history:
v7 => v8:
 devm_iio_adc_device_alloc_chaninfo_se():
 - Treat all negative values for the max ID as 'don't care'
 - Return -ENOENT instead of '0' if no channels were found.
v5 => v6:
 - Adapt to changed fwnode helper names
 - Fix spelling
v4 => v5:
 - Inline iio_adc_device_num_channels()
 - Fix Indenting function parameters
 - Combine the max channel ID checks.
v3 => v4:
 - Drop diff-channel support
 - Drop iio_adc_device_channels_by_property()
 - Add IIO_DEVICE namespace
 - Move industrialio-adc.o to top of the Makefile
 - Some styling as suggested by Andy
 - Re-consider included headers
v2 => v3: Mostly based on review comments by Jonathan
 - Support differential and single-ended channels
 - Rename iio_adc_device_get_channels() as
   iio_adc_device_channels_by_property()
 - Improve spelling
 - Drop support for cases where DT comes from parent device's node
 - Decrease loop indent by reverting node name check conditions
 - Don't set 'chan->indexed' by number of channels to keep the
   interface consistent no matter how many channels are connected.
 - Fix ID range check and related comment
RFC v1 => v2:
 - New patch
---
 drivers/iio/adc/Kconfig            |  3 ++
 drivers/iio/adc/Makefile           |  2 +
 drivers/iio/adc/industrialio-adc.c | 82 ++++++++++++++++++++++++++++++
 include/linux/iio/adc-helpers.h    | 27 ++++++++++
 4 files changed, 114 insertions(+)
 create mode 100644 drivers/iio/adc/industrialio-adc.c
 create mode 100644 include/linux/iio/adc-helpers.h

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 849c90203071..37b70a65da6f 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -6,6 +6,9 @@
 
 menu "Analog to digital converters"
 
+config IIO_ADC_HELPER
+	tristate
+
 config AB8500_GPADC
 	bool "ST-Ericsson AB8500 GPADC driver"
 	depends on AB8500_CORE && REGULATOR_AB8500
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index ee19afba62b7..1c410f483029 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -3,6 +3,8 @@
 # Makefile for IIO ADC drivers
 #
 
+obj-$(CONFIG_IIO_ADC_HELPER) += industrialio-adc.o
+
 # When adding new entries keep the list in alphabetical order
 obj-$(CONFIG_AB8500_GPADC) += ab8500-gpadc.o
 obj-$(CONFIG_AD_SIGMA_DELTA) += ad_sigma_delta.o
diff --git a/drivers/iio/adc/industrialio-adc.c b/drivers/iio/adc/industrialio-adc.c
new file mode 100644
index 000000000000..b4057230e749
--- /dev/null
+++ b/drivers/iio/adc/industrialio-adc.c
@@ -0,0 +1,82 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Helpers for parsing common ADC information from a firmware node.
+ *
+ * Copyright (c) 2025 Matti Vaittinen <mazziesaccount@gmail.com>
+ */
+
+#include <linux/device.h>
+#include <linux/errno.h>
+#include <linux/export.h>
+#include <linux/module.h>
+#include <linux/property.h>
+#include <linux/types.h>
+
+#include <linux/iio/adc-helpers.h>
+#include <linux/iio/iio.h>
+
+/**
+ * devm_iio_adc_device_alloc_chaninfo_se - allocate and fill iio_chan_spec for ADC
+ *
+ * Scan the device node for single-ended ADC channel information. Channel ID is
+ * expected to be found from the "reg" property. Allocate and populate the
+ * iio_chan_spec structure corresponding to channels that are found. The memory
+ * for iio_chan_spec structure will be freed upon device detach.
+ *
+ * @dev:		Pointer to the ADC device.
+ * @template:		Template iio_chan_spec from which the fields of all
+ *			found and allocated channels are initialized.
+ * @max_chan_id:	Maximum value of a channel ID. Use negative value if no
+ *			checking is required.
+ * @cs:			Location where pointer to allocated iio_chan_spec
+ *			should be stored.
+ *
+ * Return:	Number of found channels on success. Negative value to indicate
+ *		failure. Specifically, -ENOENT if no channel nodes were found.
+ */
+int devm_iio_adc_device_alloc_chaninfo_se(struct device *dev,
+					  const struct iio_chan_spec *template,
+					  int max_chan_id,
+					  struct iio_chan_spec **cs)
+{
+	struct iio_chan_spec *chan_array, *chan;
+	int num_chan, ret;
+
+	num_chan = iio_adc_device_num_channels(dev);
+	if (num_chan < 0)
+		return num_chan;
+
+	if (!num_chan)
+		return -ENOENT;
+
+	chan_array = devm_kcalloc(dev, num_chan, sizeof(*chan_array),
+				  GFP_KERNEL);
+	if (!chan_array)
+		return -ENOMEM;
+
+	chan = &chan_array[0];
+
+	device_for_each_named_child_node_scoped(dev, child, "channel") {
+		u32 ch;
+
+		ret = fwnode_property_read_u32(child, "reg", &ch);
+		if (ret)
+			return ret;
+
+		if (max_chan_id >= 0 && ch > max_chan_id)
+			return -ERANGE;
+
+		*chan = *template;
+		chan->channel = ch;
+		chan++;
+	}
+
+	*cs = chan_array;
+
+	return num_chan;
+}
+EXPORT_SYMBOL_NS_GPL(devm_iio_adc_device_alloc_chaninfo_se, "IIO_DRIVER");
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Matti Vaittinen <mazziesaccount@gmail.com>");
+MODULE_DESCRIPTION("IIO ADC fwnode parsing helpers");
diff --git a/include/linux/iio/adc-helpers.h b/include/linux/iio/adc-helpers.h
new file mode 100644
index 000000000000..56b092a2a4c4
--- /dev/null
+++ b/include/linux/iio/adc-helpers.h
@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+/*
+ * The industrial I/O ADC firmware property parsing helpers
+ *
+ * Copyright (c) 2025 Matti Vaittinen <mazziesaccount@gmail.com>
+ */
+
+#ifndef _INDUSTRIAL_IO_ADC_HELPERS_H_
+#define _INDUSTRIAL_IO_ADC_HELPERS_H_
+
+#include <linux/property.h>
+
+struct device;
+struct iio_chan_spec;
+
+static inline int iio_adc_device_num_channels(struct device *dev)
+{
+	return device_get_named_child_node_count(dev, "channel");
+}
+
+int devm_iio_adc_device_alloc_chaninfo_se(struct device *dev,
+					  const struct iio_chan_spec *template,
+					  int max_chan_id,
+					  struct iio_chan_spec **cs);
+
+#endif /* _INDUSTRIAL_IO_ADC_HELPERS_H_ */
-- 
2.48.1


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[PATCH v8 07/10] MAINTAINERS: Add IIO ADC helpers

[Matti Vaittinen]

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Add undersigned as a maintainer for the IIO ADC helpers.

Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
---
Revision history:
v2 =>
 - No changes
RFC v1 => v2:
 - New patch
---
 MAINTAINERS | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index 8e0736dc2ee0..5b96fb864227 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -11208,6 +11208,13 @@ L:	linux-media@vger.kernel.org
 S:	Maintained
 F:	drivers/media/rc/iguanair.c
 
+IIO ADC HELPERS
+M:	Matti Vaittinen <mazziesaccount@gmail.com>
+L:	linux-iio@vger.kernel.org
+S:	Maintained
+F:	drivers/iio/adc/industrialio-adc.c
+F:	include/linux/iio/adc-helpers.h
+
 IIO BACKEND FRAMEWORK
 M:	Nuno Sa <nuno.sa@analog.com>
 R:	Olivier Moysan <olivier.moysan@foss.st.com>
-- 
2.48.1


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Re: [PATCH v8 03/10] iio: adc: add helpers for parsing ADC nodes

[Andy Shevchenko]

On Mon, Mar 17, 2025 at 05:50:49PM +0200, Matti Vaittinen wrote:
> There are ADC ICs which may have some of the AIN pins usable for other
> functions. These ICs may have some of the AIN pins wired so that they
> should not be used for ADC.
> 
> (Preferred?) way for marking pins which can be used as ADC inputs is to
> add corresponding channels@N nodes in the device tree as described in
> the ADC binding yaml.
> 
> Add couple of helper functions which can be used to retrieve the channel
> information from the device node.

LGTM now, thanks!
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v8 02/10] property: Add functions to iterate named child

[Sakari Ailus]

Moi,

On Mon, Mar 17, 2025 at 05:50:38PM +0200, Matti Vaittinen wrote:
> There are a few use-cases where child nodes with a specific name need to
> be parsed. Code like:
> 
> fwnode_for_each_child_node()
> 	if (fwnode_name_eq())
> 		...
> 
> can be found from a various drivers/subsystems. Adding a macro for this
> can simplify things a bit.
> 
> In a few cases the data from the found nodes is later added to an array,
> which is allocated based on the number of found nodes. One example of
> such use is the IIO subsystem's ADC channel nodes, where the relevant
> nodes are named as channel[@N].
> 
> Add helpers for iterating and counting device's sub-nodes with certain
> name instead of open-coding this in every user.
> 
> Suggested-by: Jonathan Cameron <jic23@kernel.org>
> Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Reviewed-by: Marcelo Schmitt <marcelo.schmitt1@gmail.com>
> ---
> Revision history:
> v7 => v8:
>  - Fix the example in fwnode_get_named_child_node_count() documentation
>    to use the fwnode_get_named_child_node_count() and not the
>    device_get_named_child_node_count()
>  - Fix the rest of the new macro's indentiations
> v6 => v7:
>  - Improve kerneldoc
>  - Inline device_get_named_child_node_count() and change it to call
>    fwnode_get_named_child_node_count() inside
>  - Fix indentiation of the new macros
> v5 => v6:
>  - Add helpers to also iterate through the nodes.
> v4 => v5:
>  - Use given name instead of string 'channel' when counting the nodes
>  - Add also fwnode_get_child_node_count_named() as suggested by Rob.
> v3 => v4:
>  - New patch as suggested by Jonathan, see discussion in:
> https://lore.kernel.org/lkml/20250223161338.5c896280@jic23-huawei/
> ---
>  drivers/base/property.c  | 27 +++++++++++++++++++++++++++
>  include/linux/property.h | 24 ++++++++++++++++++++++++
>  2 files changed, 51 insertions(+)
> 
> diff --git a/drivers/base/property.c b/drivers/base/property.c
> index c1392743df9c..f42f32ff45fc 100644
> --- a/drivers/base/property.c
> +++ b/drivers/base/property.c
> @@ -945,6 +945,33 @@ unsigned int device_get_child_node_count(const struct device *dev)
>  }
>  EXPORT_SYMBOL_GPL(device_get_child_node_count);
>  
> +/**
> + * fwnode_get_named_child_node_count - number of child nodes with given name
> + * @fwnode: Node which child nodes are counted.
> + * @name: String to match child node name against.
> + *
> + * Scan child nodes and count all the nodes with a specific name. Potential
> + * 'number' -ending after the 'at sign' for scanned names is ignored.
> + * E.g.::
> + *   fwnode_get_named_child_node_count(fwnode, "channel");
> + * would match all the nodes::
> + *   channel { }, channel@0 {}, channel@0xabba {}...
> + *
> + * Return: the number of child nodes with a matching name for a given device.
> + */
> +unsigned int fwnode_get_named_child_node_count(const struct fwnode_handle *fwnode,
> +					       const char *name)
> +{
> +	struct fwnode_handle *child;
> +	unsigned int count = 0;
> +
> +	fwnode_for_each_named_child_node(fwnode, child, name)
> +		count++;
> +
> +	return count;
> +}
> +EXPORT_SYMBOL_GPL(fwnode_get_named_child_node_count);
> +
>  bool device_dma_supported(const struct device *dev)
>  {
>  	return fwnode_call_bool_op(dev_fwnode(dev), device_dma_supported);
> diff --git a/include/linux/property.h b/include/linux/property.h
> index e214ecd241eb..a1856e6b714c 100644
> --- a/include/linux/property.h
> +++ b/include/linux/property.h
> @@ -167,10 +167,18 @@ struct fwnode_handle *fwnode_get_next_available_child_node(
>  	for (child = fwnode_get_next_child_node(fwnode, NULL); child;	\
>  	     child = fwnode_get_next_child_node(fwnode, child))
>  
> +#define fwnode_for_each_named_child_node(fwnode, child, name)		\
> +	fwnode_for_each_child_node(fwnode, child)			\
> +		if (!fwnode_name_eq(child, name)) { } else
> +
>  #define fwnode_for_each_available_child_node(fwnode, child)		       \
>  	for (child = fwnode_get_next_available_child_node(fwnode, NULL); child;\
>  	     child = fwnode_get_next_available_child_node(fwnode, child))
>  
> +#define fwnode_for_each_available_named_child_node(fwnode, child, name)	\
> +	fwnode_for_each_available_child_node(fwnode, child)		\
> +		if (!fwnode_name_eq(child, name)) { } else
> +

OF only enumerates available nodes via the fwnode API, software nodes don't
have the concept but on ACPI I guess you could have a difference in nodes
where you have device sub-nodes that aren't available. Still, these ACPI
device nodes don't have meaningful names in this context (they're
4-character object names) so you wouldn't use them like this anyway.

So my question is: is it useful to provide this besides
fwnode_for_each_named_child_node(), given that both are effectively the
same?

>  struct fwnode_handle *device_get_next_child_node(const struct device *dev,
>  						 struct fwnode_handle *child);
>  
> @@ -178,11 +186,19 @@ struct fwnode_handle *device_get_next_child_node(const struct device *dev,
>  	for (child = device_get_next_child_node(dev, NULL); child;	\
>  	     child = device_get_next_child_node(dev, child))
>  
> +#define device_for_each_named_child_node(dev, child, name)		\
> +	device_for_each_child_node(dev, child)				\
> +		if (!fwnode_name_eq(child, name)) { } else
> +
>  #define device_for_each_child_node_scoped(dev, child)			\
>  	for (struct fwnode_handle *child __free(fwnode_handle) =	\
>  		device_get_next_child_node(dev, NULL);			\
>  	     child; child = device_get_next_child_node(dev, child))
>  
> +#define device_for_each_named_child_node_scoped(dev, child, name)	\
> +	device_for_each_child_node_scoped(dev, child)			\
> +		if (!fwnode_name_eq(child, name)) { } else
> +
>  struct fwnode_handle *fwnode_get_named_child_node(const struct fwnode_handle *fwnode,
>  						  const char *childname);
>  struct fwnode_handle *device_get_named_child_node(const struct device *dev,
> @@ -210,6 +226,14 @@ int fwnode_irq_get_byname(const struct fwnode_handle *fwnode, const char *name);
>  
>  unsigned int device_get_child_node_count(const struct device *dev);
>  
> +unsigned int fwnode_get_named_child_node_count(const struct fwnode_handle *fwnode,
> +					       const char *name);
> +static inline unsigned int device_get_named_child_node_count(const struct device *dev,
> +							     const char *name)
> +{
> +	return fwnode_get_named_child_node_count(dev_fwnode(dev), name);
> +}
> +
>  static inline int device_property_read_u8(const struct device *dev,
>  					  const char *propname, u8 *val)
>  {

-- 
Terveisin,

Sakari Ailus

Re: [PATCH v8 02/10] property: Add functions to iterate named child

[Matti Vaittinen]

Moro Sakari,

Thanks for the review.

On 18/03/2025 17:24, Sakari Ailus wrote:
> Moi,
> 
> On Mon, Mar 17, 2025 at 05:50:38PM +0200, Matti Vaittinen wrote:
>> There are a few use-cases where child nodes with a specific name need to
>> be parsed. Code like:
>>
>> fwnode_for_each_child_node()
>> 	if (fwnode_name_eq())
>> 		...
>>
>> can be found from a various drivers/subsystems. Adding a macro for this
>> can simplify things a bit.
>>
>> In a few cases the data from the found nodes is later added to an array,
>> which is allocated based on the number of found nodes. One example of
>> such use is the IIO subsystem's ADC channel nodes, where the relevant
>> nodes are named as channel[@N].
>>
>> Add helpers for iterating and counting device's sub-nodes with certain
>> name instead of open-coding this in every user.
>>
>> Suggested-by: Jonathan Cameron <jic23@kernel.org>
>> Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
>> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
>> Reviewed-by: Marcelo Schmitt <marcelo.schmitt1@gmail.com>
>> ---
>> Revision history:
>> v7 => v8:
>>   - Fix the example in fwnode_get_named_child_node_count() documentation
>>     to use the fwnode_get_named_child_node_count() and not the
>>     device_get_named_child_node_count()
>>   - Fix the rest of the new macro's indentiations
>> v6 => v7:
>>   - Improve kerneldoc
>>   - Inline device_get_named_child_node_count() and change it to call
>>     fwnode_get_named_child_node_count() inside
>>   - Fix indentiation of the new macros
>> v5 => v6:
>>   - Add helpers to also iterate through the nodes.
>> v4 => v5:
>>   - Use given name instead of string 'channel' when counting the nodes
>>   - Add also fwnode_get_child_node_count_named() as suggested by Rob.
>> v3 => v4:
>>   - New patch as suggested by Jonathan, see discussion in:
>> https://lore.kernel.org/lkml/20250223161338.5c896280@jic23-huawei/
>> ---
>>   drivers/base/property.c  | 27 +++++++++++++++++++++++++++
>>   include/linux/property.h | 24 ++++++++++++++++++++++++
>>   2 files changed, 51 insertions(+)
>>
>> diff --git a/drivers/base/property.c b/drivers/base/property.c
>> index c1392743df9c..f42f32ff45fc 100644
>> --- a/drivers/base/property.c
>> +++ b/drivers/base/property.c
>> @@ -945,6 +945,33 @@ unsigned int device_get_child_node_count(const struct device *dev)
>>   }
>>   EXPORT_SYMBOL_GPL(device_get_child_node_count);
>>   
>> +/**
>> + * fwnode_get_named_child_node_count - number of child nodes with given name
>> + * @fwnode: Node which child nodes are counted.
>> + * @name: String to match child node name against.
>> + *
>> + * Scan child nodes and count all the nodes with a specific name. Potential
>> + * 'number' -ending after the 'at sign' for scanned names is ignored.
>> + * E.g.::
>> + *   fwnode_get_named_child_node_count(fwnode, "channel");
>> + * would match all the nodes::
>> + *   channel { }, channel@0 {}, channel@0xabba {}...
>> + *
>> + * Return: the number of child nodes with a matching name for a given device.
>> + */
>> +unsigned int fwnode_get_named_child_node_count(const struct fwnode_handle *fwnode,
>> +					       const char *name)
>> +{
>> +	struct fwnode_handle *child;
>> +	unsigned int count = 0;
>> +
>> +	fwnode_for_each_named_child_node(fwnode, child, name)
>> +		count++;
>> +
>> +	return count;
>> +}
>> +EXPORT_SYMBOL_GPL(fwnode_get_named_child_node_count);
>> +
>>   bool device_dma_supported(const struct device *dev)
>>   {
>>   	return fwnode_call_bool_op(dev_fwnode(dev), device_dma_supported);
>> diff --git a/include/linux/property.h b/include/linux/property.h
>> index e214ecd241eb..a1856e6b714c 100644
>> --- a/include/linux/property.h
>> +++ b/include/linux/property.h
>> @@ -167,10 +167,18 @@ struct fwnode_handle *fwnode_get_next_available_child_node(
>>   	for (child = fwnode_get_next_child_node(fwnode, NULL); child;	\
>>   	     child = fwnode_get_next_child_node(fwnode, child))
>>   
>> +#define fwnode_for_each_named_child_node(fwnode, child, name)		\
>> +	fwnode_for_each_child_node(fwnode, child)			\
>> +		if (!fwnode_name_eq(child, name)) { } else
>> +
>>   #define fwnode_for_each_available_child_node(fwnode, child)		       \
>>   	for (child = fwnode_get_next_available_child_node(fwnode, NULL); child;\
>>   	     child = fwnode_get_next_available_child_node(fwnode, child))
>>   
>> +#define fwnode_for_each_available_named_child_node(fwnode, child, name)	\
>> +	fwnode_for_each_available_child_node(fwnode, child)		\
>> +		if (!fwnode_name_eq(child, name)) { } else
>> +
> 
> OF only enumerates available nodes via the fwnode API, software nodes don't
> have the concept but on ACPI I guess you could have a difference in nodes
> where you have device sub-nodes that aren't available. Still, these ACPI
> device nodes don't have meaningful names in this context (they're
> 4-character object names) so you wouldn't use them like this anyway.

I believe you have far better understanding on these concepts than I do. 
The reason behind adding fwnode_for_each_available_child_node() was the 
patch 10/10:

-	fwnode_for_each_available_child_node(sensors, node) {
-		if (fwnode_name_eq(node, "sensor")) {
-			if (!thp7312_sensor_parse_dt(thp7312, node))
-				num_sensors++;
-		}
+	fwnode_for_each_available_named_child_node(sensors, node, "sensor") {
+		if (!thp7312_sensor_parse_dt(thp7312, node))
+			num_sensors++;
  	}


> So my question is: is it useful to provide this besides
> fwnode_for_each_named_child_node(), given that both are effectively the
> same?

So, I suppose you're saying the existing thp7312 -driver has no real 
reason to use the 'fwnode_for_each_available_child_node()', but it could 
be using fwnode_for_each_child_node() instead?

If so, I am Ok with dropping the 
'fwnode_for_each_available_named_child_node()' and changing the 10/10 to:

-	fwnode_for_each_available_child_node(sensors, node) {
-		if (fwnode_name_eq(node, "sensor")) {
-			if (!thp7312_sensor_parse_dt(thp7312, node))
-				num_sensors++;
-		}
+	fwnode_for_each_named_child_node(sensors, node, "sensor") {
+		if (!thp7312_sensor_parse_dt(thp7312, node))
+			num_sensors++;
  	}

Do you think that'd be correct?

Yours,
	-- Matti

Re: [PATCH v8 02/10] property: Add functions to iterate named child

[Sakari Ailus]

Hei Matti,

On Wed, Mar 19, 2025 at 08:02:24AM +0200, Matti Vaittinen wrote:
> Moro Sakari,
> 
> Thanks for the review.
> 
> On 18/03/2025 17:24, Sakari Ailus wrote:
> > Moi,
> > 
> > On Mon, Mar 17, 2025 at 05:50:38PM +0200, Matti Vaittinen wrote:
> > > There are a few use-cases where child nodes with a specific name need to
> > > be parsed. Code like:
> > > 
> > > fwnode_for_each_child_node()
> > > 	if (fwnode_name_eq())
> > > 		...
> > > 
> > > can be found from a various drivers/subsystems. Adding a macro for this
> > > can simplify things a bit.
> > > 
> > > In a few cases the data from the found nodes is later added to an array,
> > > which is allocated based on the number of found nodes. One example of
> > > such use is the IIO subsystem's ADC channel nodes, where the relevant
> > > nodes are named as channel[@N].
> > > 
> > > Add helpers for iterating and counting device's sub-nodes with certain
> > > name instead of open-coding this in every user.
> > > 
> > > Suggested-by: Jonathan Cameron <jic23@kernel.org>
> > > Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
> > > Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> > > Reviewed-by: Marcelo Schmitt <marcelo.schmitt1@gmail.com>
> > > ---
> > > Revision history:
> > > v7 => v8:
> > >   - Fix the example in fwnode_get_named_child_node_count() documentation
> > >     to use the fwnode_get_named_child_node_count() and not the
> > >     device_get_named_child_node_count()
> > >   - Fix the rest of the new macro's indentiations
> > > v6 => v7:
> > >   - Improve kerneldoc
> > >   - Inline device_get_named_child_node_count() and change it to call
> > >     fwnode_get_named_child_node_count() inside
> > >   - Fix indentiation of the new macros
> > > v5 => v6:
> > >   - Add helpers to also iterate through the nodes.
> > > v4 => v5:
> > >   - Use given name instead of string 'channel' when counting the nodes
> > >   - Add also fwnode_get_child_node_count_named() as suggested by Rob.
> > > v3 => v4:
> > >   - New patch as suggested by Jonathan, see discussion in:
> > > https://lore.kernel.org/lkml/20250223161338.5c896280@jic23-huawei/
> > > ---
> > >   drivers/base/property.c  | 27 +++++++++++++++++++++++++++
> > >   include/linux/property.h | 24 ++++++++++++++++++++++++
> > >   2 files changed, 51 insertions(+)
> > > 
> > > diff --git a/drivers/base/property.c b/drivers/base/property.c
> > > index c1392743df9c..f42f32ff45fc 100644
> > > --- a/drivers/base/property.c
> > > +++ b/drivers/base/property.c
> > > @@ -945,6 +945,33 @@ unsigned int device_get_child_node_count(const struct device *dev)
> > >   }
> > >   EXPORT_SYMBOL_GPL(device_get_child_node_count);
> > > +/**
> > > + * fwnode_get_named_child_node_count - number of child nodes with given name
> > > + * @fwnode: Node which child nodes are counted.
> > > + * @name: String to match child node name against.
> > > + *
> > > + * Scan child nodes and count all the nodes with a specific name. Potential
> > > + * 'number' -ending after the 'at sign' for scanned names is ignored.
> > > + * E.g.::
> > > + *   fwnode_get_named_child_node_count(fwnode, "channel");
> > > + * would match all the nodes::
> > > + *   channel { }, channel@0 {}, channel@0xabba {}...
> > > + *
> > > + * Return: the number of child nodes with a matching name for a given device.
> > > + */
> > > +unsigned int fwnode_get_named_child_node_count(const struct fwnode_handle *fwnode,
> > > +					       const char *name)
> > > +{
> > > +	struct fwnode_handle *child;
> > > +	unsigned int count = 0;
> > > +
> > > +	fwnode_for_each_named_child_node(fwnode, child, name)
> > > +		count++;
> > > +
> > > +	return count;
> > > +}
> > > +EXPORT_SYMBOL_GPL(fwnode_get_named_child_node_count);
> > > +
> > >   bool device_dma_supported(const struct device *dev)
> > >   {
> > >   	return fwnode_call_bool_op(dev_fwnode(dev), device_dma_supported);
> > > diff --git a/include/linux/property.h b/include/linux/property.h
> > > index e214ecd241eb..a1856e6b714c 100644
> > > --- a/include/linux/property.h
> > > +++ b/include/linux/property.h
> > > @@ -167,10 +167,18 @@ struct fwnode_handle *fwnode_get_next_available_child_node(
> > >   	for (child = fwnode_get_next_child_node(fwnode, NULL); child;	\
> > >   	     child = fwnode_get_next_child_node(fwnode, child))
> > > +#define fwnode_for_each_named_child_node(fwnode, child, name)		\
> > > +	fwnode_for_each_child_node(fwnode, child)			\
> > > +		if (!fwnode_name_eq(child, name)) { } else
> > > +
> > >   #define fwnode_for_each_available_child_node(fwnode, child)		       \
> > >   	for (child = fwnode_get_next_available_child_node(fwnode, NULL); child;\
> > >   	     child = fwnode_get_next_available_child_node(fwnode, child))
> > > +#define fwnode_for_each_available_named_child_node(fwnode, child, name)	\
> > > +	fwnode_for_each_available_child_node(fwnode, child)		\
> > > +		if (!fwnode_name_eq(child, name)) { } else
> > > +
> > 
> > OF only enumerates available nodes via the fwnode API, software nodes don't
> > have the concept but on ACPI I guess you could have a difference in nodes
> > where you have device sub-nodes that aren't available. Still, these ACPI
> > device nodes don't have meaningful names in this context (they're
> > 4-character object names) so you wouldn't use them like this anyway.
> 
> I believe you have far better understanding on these concepts than I do. The
> reason behind adding fwnode_for_each_available_child_node() was the patch
> 10/10:
> 
> -	fwnode_for_each_available_child_node(sensors, node) {
> -		if (fwnode_name_eq(node, "sensor")) {
> -			if (!thp7312_sensor_parse_dt(thp7312, node))
> -				num_sensors++;
> -		}
> +	fwnode_for_each_available_named_child_node(sensors, node, "sensor") {
> +		if (!thp7312_sensor_parse_dt(thp7312, node))
> +			num_sensors++;
>  	}
> 
> 
> > So my question is: is it useful to provide this besides
> > fwnode_for_each_named_child_node(), given that both are effectively the
> > same?
> 
> So, I suppose you're saying the existing thp7312 -driver has no real reason
> to use the 'fwnode_for_each_available_child_node()', but it could be using
> fwnode_for_each_child_node() instead?
> 
> If so, I am Ok with dropping the
> 'fwnode_for_each_available_named_child_node()' and changing the 10/10 to:
> 
> -	fwnode_for_each_available_child_node(sensors, node) {
> -		if (fwnode_name_eq(node, "sensor")) {
> -			if (!thp7312_sensor_parse_dt(thp7312, node))
> -				num_sensors++;
> -		}
> +	fwnode_for_each_named_child_node(sensors, node, "sensor") {
> +		if (!thp7312_sensor_parse_dt(thp7312, node))
> +			num_sensors++;
>  	}
> 
> Do you think that'd be correct?

I'd say so. Feel free to cc me to the last patch as well.

I guess one way to make this clearer is to switch to
fwnode_for_each_child_node() in a separate patch before
fwnode_for_each_named_child_node() conversion.

There are also just a handful of users of
fwnode_for_each_available_child_node() and I guess these could be
converted, too, but I think it's outside the scope of the set.

-- 
Terveisin,

Sakari Ailus

Re: [PATCH v8 02/10] property: Add functions to iterate named child

[Matti Vaittinen]

On 19/03/2025 17:23, Sakari Ailus wrote:
> On Wed, Mar 19, 2025 at 08:02:24AM +0200, Matti Vaittinen wrote:
>> On 18/03/2025 17:24, Sakari Ailus wrote:
>>> On Mon, Mar 17, 2025 at 05:50:38PM +0200, Matti Vaittinen wrote:
>>>> There are a few use-cases where child nodes with a specific name need to
>>>> be parsed. Code like:

...

>>>> --- a/include/linux/property.h
>>>> +++ b/include/linux/property.h
>>>> @@ -167,10 +167,18 @@ struct fwnode_handle *fwnode_get_next_available_child_node(
>>>>    	for (child = fwnode_get_next_child_node(fwnode, NULL); child;	\
>>>>    	     child = fwnode_get_next_child_node(fwnode, child))
>>>> +#define fwnode_for_each_named_child_node(fwnode, child, name)		\
>>>> +	fwnode_for_each_child_node(fwnode, child)			\
>>>> +		if (!fwnode_name_eq(child, name)) { } else
>>>> +
>>>>    #define fwnode_for_each_available_child_node(fwnode, child)		       \
>>>>    	for (child = fwnode_get_next_available_child_node(fwnode, NULL); child;\
>>>>    	     child = fwnode_get_next_available_child_node(fwnode, child))
>>>> +#define fwnode_for_each_available_named_child_node(fwnode, child, name)	\
>>>> +	fwnode_for_each_available_child_node(fwnode, child)		\
>>>> +		if (!fwnode_name_eq(child, name)) { } else
>>>> +
>>>
>>> OF only enumerates available nodes via the fwnode API, software nodes don't
>>> have the concept but on ACPI I guess you could have a difference in nodes
>>> where you have device sub-nodes that aren't available. Still, these ACPI
>>> device nodes don't have meaningful names in this context (they're
>>> 4-character object names) so you wouldn't use them like this anyway.
>>
>> I believe you have far better understanding on these concepts than I do. The
>> reason behind adding fwnode_for_each_available_child_node() was the patch
>> 10/10:
>>
>> -	fwnode_for_each_available_child_node(sensors, node) {
>> -		if (fwnode_name_eq(node, "sensor")) {
>> -			if (!thp7312_sensor_parse_dt(thp7312, node))
>> -				num_sensors++;
>> -		}
>> +	fwnode_for_each_available_named_child_node(sensors, node, "sensor") {
>> +		if (!thp7312_sensor_parse_dt(thp7312, node))
>> +			num_sensors++;
>>   	}
>>
>>
>>> So my question is: is it useful to provide this besides
>>> fwnode_for_each_named_child_node(), given that both are effectively the
>>> same?
>>
>> So, I suppose you're saying the existing thp7312 -driver has no real reason
>> to use the 'fwnode_for_each_available_child_node()', but it could be using
>> fwnode_for_each_child_node() instead?
>>
>> If so, I am Ok with dropping the
>> 'fwnode_for_each_available_named_child_node()' and changing the 10/10 to:
>>
>> -	fwnode_for_each_available_child_node(sensors, node) {
>> -		if (fwnode_name_eq(node, "sensor")) {
>> -			if (!thp7312_sensor_parse_dt(thp7312, node))
>> -				num_sensors++;
>> -		}
>> +	fwnode_for_each_named_child_node(sensors, node, "sensor") {
>> +		if (!thp7312_sensor_parse_dt(thp7312, node))
>> +			num_sensors++;
>>   	}
>>
>> Do you think that'd be correct?
> 
> I'd say so. Feel free to cc me to the last patch as well.

Thanks. I'll drop the fwnode_for_each_available_named_child_node() then.

> I guess one way to make this clearer is to switch to
> fwnode_for_each_child_node() in a separate patch before
> fwnode_for_each_named_child_node() conversion.

I suppose this makes sense.

I think this series can't make it to 6.15-rc1. Meaning, these 
*_named_*() APIs perhaps land in 6.16-rc1. I assume these *_named_*() 
APIs will go through the IIO. This rather simple IIO driver's review 
took longer than I predicted, with more versions I intended (as always) 
- and I kind of dislike respinning the whole series, with this large 
audience, when changes are not interesting to the most.

Maybe it is simplest to drop the thp7312 (and gianfar) from this series, 
and respin them only when the 6.16-rc1 is out. It's going to be couple 
of months though - so there's always a risk that I forget.

The proposed change for the thp7312, from 
fwnode_for_each_available_child_node() to fwnode_for_each_child_node() 
can be done earlier though.

> There are also just a handful of users of
> fwnode_for_each_available_child_node() and I guess these could be
> converted, too, but I think it's outside the scope of the set.

Definitely not in the scope of the bd79124 support :)

Yours,
	-- Matti

Re: [PATCH v8 02/10] property: Add functions to iterate named child

[Jonathan Cameron]

On Thu, 20 Mar 2025 08:43:44 +0200
Matti Vaittinen <mazziesaccount@gmail.com> wrote:

> On 19/03/2025 17:23, Sakari Ailus wrote:
> > On Wed, Mar 19, 2025 at 08:02:24AM +0200, Matti Vaittinen wrote:  
> >> On 18/03/2025 17:24, Sakari Ailus wrote:  
> >>> On Mon, Mar 17, 2025 at 05:50:38PM +0200, Matti Vaittinen wrote:  
> >>>> There are a few use-cases where child nodes with a specific name need to
> >>>> be parsed. Code like:  
> 
> ...
> 
> >>>> --- a/include/linux/property.h
> >>>> +++ b/include/linux/property.h
> >>>> @@ -167,10 +167,18 @@ struct fwnode_handle *fwnode_get_next_available_child_node(
> >>>>    	for (child = fwnode_get_next_child_node(fwnode, NULL); child;	\
> >>>>    	     child = fwnode_get_next_child_node(fwnode, child))
> >>>> +#define fwnode_for_each_named_child_node(fwnode, child, name)		\
> >>>> +	fwnode_for_each_child_node(fwnode, child)			\
> >>>> +		if (!fwnode_name_eq(child, name)) { } else
> >>>> +
> >>>>    #define fwnode_for_each_available_child_node(fwnode, child)		       \
> >>>>    	for (child = fwnode_get_next_available_child_node(fwnode, NULL); child;\
> >>>>    	     child = fwnode_get_next_available_child_node(fwnode, child))
> >>>> +#define fwnode_for_each_available_named_child_node(fwnode, child, name)	\
> >>>> +	fwnode_for_each_available_child_node(fwnode, child)		\
> >>>> +		if (!fwnode_name_eq(child, name)) { } else
> >>>> +  
> >>>
> >>> OF only enumerates available nodes via the fwnode API, software nodes don't
> >>> have the concept but on ACPI I guess you could have a difference in nodes
> >>> where you have device sub-nodes that aren't available. Still, these ACPI
> >>> device nodes don't have meaningful names in this context (they're
> >>> 4-character object names) so you wouldn't use them like this anyway.  
> >>
> >> I believe you have far better understanding on these concepts than I do. The
> >> reason behind adding fwnode_for_each_available_child_node() was the patch
> >> 10/10:
> >>
> >> -	fwnode_for_each_available_child_node(sensors, node) {
> >> -		if (fwnode_name_eq(node, "sensor")) {
> >> -			if (!thp7312_sensor_parse_dt(thp7312, node))
> >> -				num_sensors++;
> >> -		}
> >> +	fwnode_for_each_available_named_child_node(sensors, node, "sensor") {
> >> +		if (!thp7312_sensor_parse_dt(thp7312, node))
> >> +			num_sensors++;
> >>   	}
> >>
> >>  
> >>> So my question is: is it useful to provide this besides
> >>> fwnode_for_each_named_child_node(), given that both are effectively the
> >>> same?  
> >>
> >> So, I suppose you're saying the existing thp7312 -driver has no real reason
> >> to use the 'fwnode_for_each_available_child_node()', but it could be using
> >> fwnode_for_each_child_node() instead?
> >>
> >> If so, I am Ok with dropping the
> >> 'fwnode_for_each_available_named_child_node()' and changing the 10/10 to:
> >>
> >> -	fwnode_for_each_available_child_node(sensors, node) {
> >> -		if (fwnode_name_eq(node, "sensor")) {
> >> -			if (!thp7312_sensor_parse_dt(thp7312, node))
> >> -				num_sensors++;
> >> -		}
> >> +	fwnode_for_each_named_child_node(sensors, node, "sensor") {
> >> +		if (!thp7312_sensor_parse_dt(thp7312, node))
> >> +			num_sensors++;
> >>   	}
> >>
> >> Do you think that'd be correct?  
> > 
> > I'd say so. Feel free to cc me to the last patch as well.  
> 
> Thanks. I'll drop the fwnode_for_each_available_named_child_node() then.
> 
> > I guess one way to make this clearer is to switch to
> > fwnode_for_each_child_node() in a separate patch before
> > fwnode_for_each_named_child_node() conversion.  
> 
> I suppose this makes sense.

this _available_ thing is ancient history that has tripped us up
many times before. I've very keen to not see another case sneaking
in.  Whether we can definitely 'fix' all existing cases is a different
question..

> 
> I think this series can't make it to 6.15-rc1. Meaning, these 
> *_named_*() APIs perhaps land in 6.16-rc1. I assume these *_named_*() 
> APIs will go through the IIO. This rather simple IIO driver's review 
> took longer than I predicted, with more versions I intended (as always) 
> - and I kind of dislike respinning the whole series, with this large 
> audience, when changes are not interesting to the most.
> 
> Maybe it is simplest to drop the thp7312 (and gianfar) from this series, 
> and respin them only when the 6.16-rc1 is out. It's going to be couple 
> of months though - so there's always a risk that I forget.
> 
> The proposed change for the thp7312, from 
> fwnode_for_each_available_child_node() to fwnode_for_each_child_node() 
> can be done earlier though.
> 
> > There are also just a handful of users of
> > fwnode_for_each_available_child_node() and I guess these could be
> > converted, too, but I think it's outside the scope of the set.  
> 
> Definitely not in the scope of the bd79124 support :)
Agreed. Break this series up however you like and entirely up to
you whether you do further cleanup of other bits of the kernel!

Jonathan

> 
> Yours,
> 	-- Matti