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* [PATCH v9 0/8] Support ROHM BD79124 ADC
@ 2025-03-20  8:20 Matti Vaittinen
  2025-03-20  8:20 ` [PATCH v9 1/8] dt-bindings: ROHM BD79124 ADC/GPO Matti Vaittinen
                   ` (3 more replies)
  0 siblings, 4 replies; 5+ messages in thread
From: Matti Vaittinen @ 2025-03-20  8:20 UTC (permalink / raw)
  To: Matti Vaittinen, Matti Vaittinen
  Cc: Jonathan Cameron, Lars-Peter Clausen, Rob Herring,
	Krzysztof Kozlowski, Conor Dooley, Andy Shevchenko, Daniel Scally,
	Heikki Krogerus, Sakari Ailus, Greg Kroah-Hartman,
	Rafael J. Wysocki, Danilo Krummrich, Matti Vaittinen,
	Lad Prabhakar, Chen-Yu Tsai, Jernej Skrabec, Samuel Holland,
	Nuno Sa, David Lechner, Javier Carrasco, Guillaume Stols,
	Olivier Moysan, Dumitru Ceclan, Trevor Gamblin, Matteo Martelli,
	Alisa-Dariana Roman, AngeloGioacchino Del Regno,
	João Paulo Gonçalves, Ramona Alexandra Nechita,
	linux-iio, devicetree, linux-kernel, linux-acpi,
	linux-renesas-soc, linux-arm-kernel, linux-sunxi

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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.

The rzg2l_adc and the sun20i-gpadc are converted to use the new ADC helper.

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: The rzg2l_adc and the sun20i-gpadc 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:

v8 => v9:
 - Drop the gianfar and the thp7312 drivers from the series to limit the
   review noise and to simplify the merging. They can be submitted later
   as separate changes.
 - Drop the fwnode_for_each_available_named_child() as suggested by
   Sakari.
 - BD79124 driver styling and fixes

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 (8):
  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

 .../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 +-
 include/linux/iio/adc-helpers.h               |   27 +
 include/linux/property.h                      |   20 +
 11 files changed, 1470 insertions(+), 48 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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^ permalink raw reply	[flat|nested] 5+ messages in thread

* [PATCH v9 1/8] dt-bindings: ROHM BD79124 ADC/GPO
  2025-03-20  8:20 [PATCH v9 0/8] Support ROHM BD79124 ADC Matti Vaittinen
@ 2025-03-20  8:20 ` Matti Vaittinen
  2025-03-20  8:21 ` [PATCH v9 2/8] property: Add functions to iterate named child Matti Vaittinen
                   ` (2 subsequent siblings)
  3 siblings, 0 replies; 5+ messages in thread
From: Matti Vaittinen @ 2025-03-20  8:20 UTC (permalink / raw)
  To: Matti Vaittinen, Matti Vaittinen
  Cc: Jonathan Cameron, Lars-Peter Clausen, Rob Herring,
	Krzysztof Kozlowski, Conor Dooley, Matti Vaittinen, linux-iio,
	devicetree, linux-kernel

[-- Attachment #1: Type: text/plain, Size: 3475 bytes --]

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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^ permalink raw reply related	[flat|nested] 5+ messages in thread

* [PATCH v9 2/8] property: Add functions to iterate named child
  2025-03-20  8:20 [PATCH v9 0/8] Support ROHM BD79124 ADC Matti Vaittinen
  2025-03-20  8:20 ` [PATCH v9 1/8] dt-bindings: ROHM BD79124 ADC/GPO Matti Vaittinen
@ 2025-03-20  8:21 ` Matti Vaittinen
  2025-03-20  8:21 ` [PATCH v9 3/8] iio: adc: add helpers for parsing ADC nodes Matti Vaittinen
  2025-03-20  8:22 ` [PATCH v9 7/8] MAINTAINERS: Add IIO ADC helpers Matti Vaittinen
  3 siblings, 0 replies; 5+ messages in thread
From: Matti Vaittinen @ 2025-03-20  8:21 UTC (permalink / raw)
  To: Matti Vaittinen, Matti Vaittinen
  Cc: Jonathan Cameron, Lars-Peter Clausen, Rob Herring,
	Krzysztof Kozlowski, Conor Dooley, Andy Shevchenko, Daniel Scally,
	Heikki Krogerus, Sakari Ailus, Greg Kroah-Hartman,
	Rafael J. Wysocki, Danilo Krummrich, Matti Vaittinen,
	Lad Prabhakar, Chen-Yu Tsai, Jernej Skrabec, Samuel Holland,
	Nuno Sa, David Lechner, Javier Carrasco, Guillaume Stols,
	Olivier Moysan, Dumitru Ceclan, Trevor Gamblin, Matteo Martelli,
	Alisa-Dariana Roman, AngeloGioacchino Del Regno,
	João Paulo Gonçalves, Ramona Alexandra Nechita,
	linux-iio, devicetree, linux-kernel, linux-acpi,
	linux-renesas-soc, linux-arm-kernel, linux-sunxi

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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:
v8 => v9:
 - Drop the fwnode_for_each_available_named_child_node() as suggested
   by Sakari during v8 review:
   https://lore.kernel.org/all/Z9mQPJwnKAkPHriT@kekkonen.localdomain/
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 | 20 ++++++++++++++++++++
 2 files changed, 47 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..3e83babac0b0 100644
--- a/include/linux/property.h
+++ b/include/linux/property.h
@@ -167,6 +167,10 @@ 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))
@@ -178,11 +182,19 @@ 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 +222,14 @@ 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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^ permalink raw reply related	[flat|nested] 5+ messages in thread

* [PATCH v9 3/8] iio: adc: add helpers for parsing ADC nodes
  2025-03-20  8:20 [PATCH v9 0/8] Support ROHM BD79124 ADC Matti Vaittinen
  2025-03-20  8:20 ` [PATCH v9 1/8] dt-bindings: ROHM BD79124 ADC/GPO Matti Vaittinen
  2025-03-20  8:21 ` [PATCH v9 2/8] property: Add functions to iterate named child Matti Vaittinen
@ 2025-03-20  8:21 ` Matti Vaittinen
  2025-03-20  8:22 ` [PATCH v9 7/8] MAINTAINERS: Add IIO ADC helpers Matti Vaittinen
  3 siblings, 0 replies; 5+ messages in thread
From: Matti Vaittinen @ 2025-03-20  8:21 UTC (permalink / raw)
  To: Matti Vaittinen, Matti Vaittinen
  Cc: Jonathan Cameron, Lars-Peter Clausen, Andy Shevchenko,
	Matti Vaittinen, Lad Prabhakar, Chen-Yu Tsai, Jernej Skrabec,
	Samuel Holland, Nuno Sa, David Lechner, Javier Carrasco,
	Guillaume Stols, Dumitru Ceclan, Trevor Gamblin, Matteo Martelli,
	Alisa-Dariana Roman, Ramona Alexandra Nechita,
	AngeloGioacchino Del Regno, linux-iio, devicetree, linux-kernel,
	linux-acpi, linux-renesas-soc, linux-arm-kernel, linux-sunxi

[-- Attachment #1: Type: text/plain, Size: 6615 bytes --]

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>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

---
Revision history:
v8 =>
 - No changes
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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^ permalink raw reply related	[flat|nested] 5+ messages in thread

* [PATCH v9 7/8] MAINTAINERS: Add IIO ADC helpers
  2025-03-20  8:20 [PATCH v9 0/8] Support ROHM BD79124 ADC Matti Vaittinen
                   ` (2 preceding siblings ...)
  2025-03-20  8:21 ` [PATCH v9 3/8] iio: adc: add helpers for parsing ADC nodes Matti Vaittinen
@ 2025-03-20  8:22 ` Matti Vaittinen
  3 siblings, 0 replies; 5+ messages in thread
From: Matti Vaittinen @ 2025-03-20  8:22 UTC (permalink / raw)
  To: Matti Vaittinen, Matti Vaittinen
  Cc: Jonathan Cameron, Lars-Peter Clausen, Andy Shevchenko,
	Matti Vaittinen, Lad Prabhakar, Chen-Yu Tsai, Jernej Skrabec,
	Samuel Holland, Nuno Sa, David Lechner, Javier Carrasco,
	Guillaume Stols, Dumitru Ceclan, Trevor Gamblin, Matteo Martelli,
	Alisa-Dariana Roman, Ramona Alexandra Nechita,
	AngeloGioacchino Del Regno, linux-iio, devicetree, linux-kernel,
	linux-acpi, linux-renesas-soc, linux-arm-kernel, linux-sunxi

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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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^ permalink raw reply related	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2025-03-20  8:22 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2025-03-20  8:20 [PATCH v9 0/8] Support ROHM BD79124 ADC Matti Vaittinen
2025-03-20  8:20 ` [PATCH v9 1/8] dt-bindings: ROHM BD79124 ADC/GPO Matti Vaittinen
2025-03-20  8:21 ` [PATCH v9 2/8] property: Add functions to iterate named child Matti Vaittinen
2025-03-20  8:21 ` [PATCH v9 3/8] iio: adc: add helpers for parsing ADC nodes Matti Vaittinen
2025-03-20  8:22 ` [PATCH v9 7/8] MAINTAINERS: Add IIO ADC helpers Matti Vaittinen

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