[PATCH v3 0/8] Introduce max12xx ADC support

[PATCH v3 0/8] Introduce max12xx ADC support

[Miquel Raynal]

Hello, here is a patchset updating the existing max1027.c driver (for
10-bit max1027/29/31 ADCs) with a few corrections/improvements and
then introducing their 12-bit cousins named max1227/29/31.

As on my hardware setup the "start conversion" and "end of conversion"
pin are not wired (which is absolutely fine for this chip), I also
updated the driver and the bindings to support optional interrupts. In
this case, triggered buffers are not available and the user must poll
the value from sysfs.

Thanks,
Miquèl


Changes in v3:
==============
* Updated the commit message of the patch adding debugfs read access
  to better explain why I decided to limit the number of bytes read to
  two.
* Updated the macros to define the number of channels per device as
  proposed by Jonathan.
* Re-used the realbits entry instead of adding my own (called .depth).
* Started doing DT-bindings yaml conversion, but realized that after
  the first patch offering the interrupt as optional, the
  documentation was fitting pretty well the trivial devices
  representation. Dropped the specific bindings files and updated the
  trivial devices list instead.

Changes in v2:
==============
* Removed the addition of three compatibles from patch 4 (the
  preparation patch) to add these lines back in patch 5 (the actual
  introduction).


Miquel Raynal (8):
  iio: adc: max1027: Add debugfs register read support
  iio: adc: max1027: Make it optional to use interrupts
  iio: adc: max1027: Reset the device at probe time
  iio: adc: max1027: Prepare the introduction of different resolutions
  iio: adc: max1027: Introduce 12-bit devices support
  dt-bindings: iio: adc: max1027: Mark interrupts as optional
  dt-bindings: Add 1027/1029/1031 SPI ADCs as trivial devices
  dt-bindings: Add max12xx SPI ADC series as trivial devices

 .../bindings/iio/adc/max1027-adc.txt          |  12 +-
 .../devicetree/bindings/trivial-devices.yaml  |  12 ++
 drivers/iio/adc/Kconfig                       |   4 +-
 drivers/iio/adc/max1027.c                     | 180 +++++++++++-------
 4 files changed, 135 insertions(+), 73 deletions(-)

-- 
2.20.1

[PATCH v3 1/8] iio: adc: max1027: Add debugfs register read support

[Miquel Raynal]

Until now, only write operations were supported. Force two bytes read
operation when reading, which should fit most of the development
purposes. Of course, extended operations like buffered reads on
multiple channels or even temperature + voltage reads will not be read
entirely. Usually, just starting a new operation will work but in any
case a software reset (done through the debufs interface too) will
return the device in a usable state.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
---
 drivers/iio/adc/max1027.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/adc/max1027.c b/drivers/iio/adc/max1027.c
index 214883458582..6cdfe9ef73fc 100644
--- a/drivers/iio/adc/max1027.c
+++ b/drivers/iio/adc/max1027.c
@@ -309,8 +309,11 @@ static int max1027_debugfs_reg_access(struct iio_dev *indio_dev,
 	struct max1027_state *st = iio_priv(indio_dev);
 	u8 *val = (u8 *)st->buffer;
 
-	if (readval != NULL)
-		return -EINVAL;
+	if (readval) {
+		int ret = spi_read(st->spi, val, 2);
+		*readval = be16_to_cpu(st->buffer[0]);
+		return ret;
+	}
 
 	*val = (u8)writeval;
 	return spi_write(st->spi, val, 1);
-- 
2.20.1

[PATCH v3 2/8] iio: adc: max1027: Make it optional to use interrupts

[Miquel Raynal]

The chip has a 'start conversion' and a 'end of conversion' pair of
pins. They can be used but this is absolutely not mandatory as regular
polling of the value is totally fine with the current internal
clocking setup. Turn the interrupts optional and do not error out if
they are not inquired in the device tree. This has the effect to
prevent triggered buffers use though.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
---
 drivers/iio/adc/max1027.c | 57 +++++++++++++++++++++------------------
 1 file changed, 31 insertions(+), 26 deletions(-)

diff --git a/drivers/iio/adc/max1027.c b/drivers/iio/adc/max1027.c
index 6cdfe9ef73fc..823223b77a70 100644
--- a/drivers/iio/adc/max1027.c
+++ b/drivers/iio/adc/max1027.c
@@ -430,35 +430,40 @@ static int max1027_probe(struct spi_device *spi)
 		return -ENOMEM;
 	}
 
-	ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev,
-					&iio_pollfunc_store_time,
-					&max1027_trigger_handler, NULL);
-	if (ret < 0) {
-		dev_err(&indio_dev->dev, "Failed to setup buffer\n");
-		return ret;
-	}
+	if (spi->irq) {
+		ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev,
+						      &iio_pollfunc_store_time,
+						      &max1027_trigger_handler,
+						      NULL);
+		if (ret < 0) {
+			dev_err(&indio_dev->dev, "Failed to setup buffer\n");
+			return ret;
+		}
 
-	st->trig = devm_iio_trigger_alloc(&spi->dev, "%s-trigger",
-							indio_dev->name);
-	if (st->trig == NULL) {
-		ret = -ENOMEM;
-		dev_err(&indio_dev->dev, "Failed to allocate iio trigger\n");
-		return ret;
-	}
+		st->trig = devm_iio_trigger_alloc(&spi->dev, "%s-trigger",
+						  indio_dev->name);
+		if (st->trig == NULL) {
+			ret = -ENOMEM;
+			dev_err(&indio_dev->dev,
+				"Failed to allocate iio trigger\n");
+			return ret;
+		}
 
-	st->trig->ops = &max1027_trigger_ops;
-	st->trig->dev.parent = &spi->dev;
-	iio_trigger_set_drvdata(st->trig, indio_dev);
-	iio_trigger_register(st->trig);
+		st->trig->ops = &max1027_trigger_ops;
+		st->trig->dev.parent = &spi->dev;
+		iio_trigger_set_drvdata(st->trig, indio_dev);
+		iio_trigger_register(st->trig);
 
-	ret = devm_request_threaded_irq(&spi->dev, spi->irq,
-					iio_trigger_generic_data_rdy_poll,
-					NULL,
-					IRQF_TRIGGER_FALLING,
-					spi->dev.driver->name, st->trig);
-	if (ret < 0) {
-		dev_err(&indio_dev->dev, "Failed to allocate IRQ.\n");
-		return ret;
+		ret = devm_request_threaded_irq(&spi->dev, spi->irq,
+						iio_trigger_generic_data_rdy_poll,
+						NULL,
+						IRQF_TRIGGER_FALLING,
+						spi->dev.driver->name,
+						st->trig);
+		if (ret < 0) {
+			dev_err(&indio_dev->dev, "Failed to allocate IRQ.\n");
+			return ret;
+		}
 	}
 
 	/* Disable averaging */
-- 
2.20.1

[PATCH v3 3/8] iio: adc: max1027: Reset the device at probe time

[Miquel Raynal]

All the registers are configured by the driver, let's reset the chip
at probe time, avoiding any conflict with a possible earlier
configuration.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
---
 drivers/iio/adc/max1027.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/iio/adc/max1027.c b/drivers/iio/adc/max1027.c
index 823223b77a70..f9b473ee6711 100644
--- a/drivers/iio/adc/max1027.c
+++ b/drivers/iio/adc/max1027.c
@@ -466,6 +466,14 @@ static int max1027_probe(struct spi_device *spi)
 		}
 	}
 
+	/* Internal reset */
+	st->reg = MAX1027_RST_REG;
+	ret = spi_write(st->spi, &st->reg, 1);
+	if (ret < 0) {
+		dev_err(&indio_dev->dev, "Failed to reset the ADC\n");
+		return ret;
+	}
+
 	/* Disable averaging */
 	st->reg = MAX1027_AVG_REG;
 	ret = spi_write(st->spi, &st->reg, 1);
-- 
2.20.1

[PATCH v3 4/8] iio: adc: max1027: Prepare the introduction of different resolutions

[Miquel Raynal]

Maxim's max1027/29/31 series returns the measured voltages with a
resolution of 10 bits. There is a very similar series, max1227/29/31
which works identically but uses a resolution of 12 bits. Prepare the
support for these chips by turning the 'depth' into a macro parameter
instead of hardcoding it everywhere. Also reorganize just a bit the
macros at the top to avoid repeating tens of lines when adding support
for a new chip.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
---
 drivers/iio/adc/max1027.c | 74 +++++++++++++++++----------------------
 1 file changed, 32 insertions(+), 42 deletions(-)

diff --git a/drivers/iio/adc/max1027.c b/drivers/iio/adc/max1027.c
index f9b473ee6711..8b449044bef5 100644
--- a/drivers/iio/adc/max1027.c
+++ b/drivers/iio/adc/max1027.c
@@ -83,7 +83,7 @@ static const struct of_device_id max1027_adc_dt_ids[] = {
 MODULE_DEVICE_TABLE(of, max1027_adc_dt_ids);
 #endif
 
-#define MAX1027_V_CHAN(index)						\
+#define MAX1027_V_CHAN(index, depth)					\
 	{								\
 		.type = IIO_VOLTAGE,					\
 		.indexed = 1,						\
@@ -93,7 +93,7 @@ MODULE_DEVICE_TABLE(of, max1027_adc_dt_ids);
 		.scan_index = index + 1,				\
 		.scan_type = {						\
 			.sign = 'u',					\
-			.realbits = 10,					\
+			.realbits = depth,				\
 			.storagebits = 16,				\
 			.shift = 2,					\
 			.endianness = IIO_BE,				\
@@ -115,52 +115,42 @@ MODULE_DEVICE_TABLE(of, max1027_adc_dt_ids);
 		},							\
 	}
 
+#define MAX1X27_CHANNELS(depth)			\
+	MAX1027_T_CHAN,				\
+	MAX1027_V_CHAN(0, depth),		\
+	MAX1027_V_CHAN(1, depth),		\
+	MAX1027_V_CHAN(2, depth),		\
+	MAX1027_V_CHAN(3, depth),		\
+	MAX1027_V_CHAN(4, depth),		\
+	MAX1027_V_CHAN(5, depth),		\
+	MAX1027_V_CHAN(6, depth),		\
+	MAX1027_V_CHAN(7, depth)
+
+#define MAX1X29_CHANNELS(depth)			\
+	MAX1X27_CHANNELS(depth),		\
+	MAX1027_V_CHAN(8, depth),		\
+	MAX1027_V_CHAN(9, depth),		\
+	MAX1027_V_CHAN(10, depth),		\
+	MAX1027_V_CHAN(11, depth)
+
+#define MAX1X31_CHANNELS(depth)			\
+	MAX1X27_CHANNELS(depth),		\
+	MAX1X29_CHANNELS(depth),		\
+	MAX1027_V_CHAN(12, depth),		\
+	MAX1027_V_CHAN(13, depth),		\
+	MAX1027_V_CHAN(14, depth),		\
+	MAX1027_V_CHAN(15, depth)
+
 static const struct iio_chan_spec max1027_channels[] = {
-	MAX1027_T_CHAN,
-	MAX1027_V_CHAN(0),
-	MAX1027_V_CHAN(1),
-	MAX1027_V_CHAN(2),
-	MAX1027_V_CHAN(3),
-	MAX1027_V_CHAN(4),
-	MAX1027_V_CHAN(5),
-	MAX1027_V_CHAN(6),
-	MAX1027_V_CHAN(7)
+	MAX1X27_CHANNELS(10),
 };
 
 static const struct iio_chan_spec max1029_channels[] = {
-	MAX1027_T_CHAN,
-	MAX1027_V_CHAN(0),
-	MAX1027_V_CHAN(1),
-	MAX1027_V_CHAN(2),
-	MAX1027_V_CHAN(3),
-	MAX1027_V_CHAN(4),
-	MAX1027_V_CHAN(5),
-	MAX1027_V_CHAN(6),
-	MAX1027_V_CHAN(7),
-	MAX1027_V_CHAN(8),
-	MAX1027_V_CHAN(9),
-	MAX1027_V_CHAN(10),
-	MAX1027_V_CHAN(11)
+	MAX1X29_CHANNELS(10),
 };
 
 static const struct iio_chan_spec max1031_channels[] = {
-	MAX1027_T_CHAN,
-	MAX1027_V_CHAN(0),
-	MAX1027_V_CHAN(1),
-	MAX1027_V_CHAN(2),
-	MAX1027_V_CHAN(3),
-	MAX1027_V_CHAN(4),
-	MAX1027_V_CHAN(5),
-	MAX1027_V_CHAN(6),
-	MAX1027_V_CHAN(7),
-	MAX1027_V_CHAN(8),
-	MAX1027_V_CHAN(9),
-	MAX1027_V_CHAN(10),
-	MAX1027_V_CHAN(11),
-	MAX1027_V_CHAN(12),
-	MAX1027_V_CHAN(13),
-	MAX1027_V_CHAN(14),
-	MAX1027_V_CHAN(15)
+	MAX1X31_CHANNELS(10),
 };
 
 static const unsigned long max1027_available_scan_masks[] = {
@@ -284,7 +274,7 @@ static int max1027_read_raw(struct iio_dev *indio_dev,
 			break;
 		case IIO_VOLTAGE:
 			*val = 2500;
-			*val2 = 10;
+			*val2 = chan->scan_type.realbits;
 			ret = IIO_VAL_FRACTIONAL_LOG2;
 			break;
 		default:
-- 
2.20.1

[PATCH v3 5/8] iio: adc: max1027: Introduce 12-bit devices support

[Miquel Raynal]

Maxim's max12xx series is very similar to the max10xx series, with the
difference of the measurements depth which is upgraded from 10 to 12
bits per channel. Everything else looks the same.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
---
 drivers/iio/adc/Kconfig   |  4 ++--
 drivers/iio/adc/max1027.c | 38 +++++++++++++++++++++++++++++++++++++-
 2 files changed, 39 insertions(+), 3 deletions(-)

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index f0af3a42f53c..6ac16d738822 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -508,8 +508,8 @@ config MAX1027
 	select IIO_BUFFER
 	select IIO_TRIGGERED_BUFFER
 	help
-	  Say yes here to build support for Maxim SPI ADC models
-	  max1027, max1029 and max1031.
+	  Say yes here to build support for Maxim SPI {10,12}-bit ADC models:
+	  max1027, max1029, max1031, max1227, max1229 and max1231.
 
 	  To compile this driver as a module, choose M here: the module will be
 	  called max1027.
diff --git a/drivers/iio/adc/max1027.c b/drivers/iio/adc/max1027.c
index 8b449044bef5..e171db20c04a 100644
--- a/drivers/iio/adc/max1027.c
+++ b/drivers/iio/adc/max1027.c
@@ -63,12 +63,18 @@ enum max1027_id {
 	max1027,
 	max1029,
 	max1031,
+	max1227,
+	max1229,
+	max1231,
 };
 
 static const struct spi_device_id max1027_id[] = {
 	{"max1027", max1027},
 	{"max1029", max1029},
 	{"max1031", max1031},
+	{"max1227", max1227},
+	{"max1229", max1229},
+	{"max1231", max1231},
 	{}
 };
 MODULE_DEVICE_TABLE(spi, max1027_id);
@@ -78,6 +84,9 @@ static const struct of_device_id max1027_adc_dt_ids[] = {
 	{ .compatible = "maxim,max1027" },
 	{ .compatible = "maxim,max1029" },
 	{ .compatible = "maxim,max1031" },
+	{ .compatible = "maxim,max1227" },
+	{ .compatible = "maxim,max1229" },
+	{ .compatible = "maxim,max1231" },
 	{},
 };
 MODULE_DEVICE_TABLE(of, max1027_adc_dt_ids);
@@ -153,6 +162,18 @@ static const struct iio_chan_spec max1031_channels[] = {
 	MAX1X31_CHANNELS(10),
 };
 
+static const struct iio_chan_spec max1227_channels[] = {
+	MAX1X27_CHANNELS(12),
+};
+
+static const struct iio_chan_spec max1229_channels[] = {
+	MAX1X29_CHANNELS(12),
+};
+
+static const struct iio_chan_spec max1231_channels[] = {
+	MAX1X31_CHANNELS(12),
+};
+
 static const unsigned long max1027_available_scan_masks[] = {
 	0x000001ff,
 	0x00000000,
@@ -190,6 +211,21 @@ static const struct max1027_chip_info max1027_chip_info_tbl[] = {
 		.num_channels = ARRAY_SIZE(max1031_channels),
 		.available_scan_masks = max1031_available_scan_masks,
 	},
+	[max1227] = {
+		.channels = max1227_channels,
+		.num_channels = ARRAY_SIZE(max1227_channels),
+		.available_scan_masks = max1027_available_scan_masks,
+	},
+	[max1229] = {
+		.channels = max1229_channels,
+		.num_channels = ARRAY_SIZE(max1229_channels),
+		.available_scan_masks = max1029_available_scan_masks,
+	},
+	[max1231] = {
+		.channels = max1231_channels,
+		.num_channels = ARRAY_SIZE(max1231_channels),
+		.available_scan_masks = max1031_available_scan_masks,
+	},
 };
 
 struct max1027_state {
@@ -486,5 +522,5 @@ static struct spi_driver max1027_driver = {
 module_spi_driver(max1027_driver);
 
 MODULE_AUTHOR("Philippe Reynes <tremyfr@yahoo.fr>");
-MODULE_DESCRIPTION("MAX1027/MAX1029/MAX1031 ADC");
+MODULE_DESCRIPTION("MAX1X27/MAX1X29/MAX1X31 ADC");
 MODULE_LICENSE("GPL v2");
-- 
2.20.1

[PATCH v3 6/8] dt-bindings: iio: adc: max1027: Mark interrupts as optional

[Miquel Raynal]

The chips have a 'start conversion' and a 'end of conversion' pair of
pins. They can be used but this is absolutely not mandatory as regular
polling is supported by the chip depending on its internal clocking
setup.

There is no physical reason to force the use of interrupts so turn
them optional.

Also, once the interrupt turned optional, these devices fit perfectly
the "trivial devices" described in the generic (yaml) bindings file, so
instead of converting this text file to json schema, we can just add
the relevant compatibles in:
Documentation/devicetree/bindings/trivial-devices.yaml.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
---
 Documentation/devicetree/bindings/iio/adc/max1027-adc.txt | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Documentation/devicetree/bindings/iio/adc/max1027-adc.txt b/Documentation/devicetree/bindings/iio/adc/max1027-adc.txt
index e680c61dfb84..7b23d68f655c 100644
--- a/Documentation/devicetree/bindings/iio/adc/max1027-adc.txt
+++ b/Documentation/devicetree/bindings/iio/adc/max1027-adc.txt
@@ -3,6 +3,8 @@
 Required properties:
   - compatible: Should be "maxim,max1027" or "maxim,max1029" or "maxim,max1031"
   - reg: SPI chip select number for the device
+
+Optional properties:
   - interrupts: IRQ line for the ADC
   see: Documentation/devicetree/bindings/interrupt-controller/interrupts.txt
 
-- 
2.20.1

[PATCH v3 7/8] dt-bindings: Add 1027/1029/1031 SPI ADCs as trivial devices

[Miquel Raynal]

In the same time, remove the dedicated bindings file which is now
useless.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
---
 .../bindings/iio/adc/max1027-adc.txt          | 22 -------------------
 .../devicetree/bindings/trivial-devices.yaml  |  6 +++++
 2 files changed, 6 insertions(+), 22 deletions(-)
 delete mode 100644 Documentation/devicetree/bindings/iio/adc/max1027-adc.txt

diff --git a/Documentation/devicetree/bindings/iio/adc/max1027-adc.txt b/Documentation/devicetree/bindings/iio/adc/max1027-adc.txt
deleted file mode 100644
index 7b23d68f655c..000000000000
--- a/Documentation/devicetree/bindings/iio/adc/max1027-adc.txt
+++ /dev/null
@@ -1,22 +0,0 @@
-* Maxim 1027/1029/1031 Analog to Digital Converter (ADC)
-
-Required properties:
-  - compatible: Should be "maxim,max1027" or "maxim,max1029" or "maxim,max1031"
-  - reg: SPI chip select number for the device
-
-Optional properties:
-  - interrupts: IRQ line for the ADC
-  see: Documentation/devicetree/bindings/interrupt-controller/interrupts.txt
-
-Recommended properties:
-- spi-max-frequency: Definition as per
-                     Documentation/devicetree/bindings/spi/spi-bus.txt
-
-Example:
-adc@0 {
-	compatible = "maxim,max1027";
-	reg = <0>;
-	interrupt-parent = <&gpio5>;
-	interrupts = <15 IRQ_TYPE_EDGE_RISING>;
-	spi-max-frequency = <1000000>;
-};
diff --git a/Documentation/devicetree/bindings/trivial-devices.yaml b/Documentation/devicetree/bindings/trivial-devices.yaml
index 870ac52d2225..e0095ecb472f 100644
--- a/Documentation/devicetree/bindings/trivial-devices.yaml
+++ b/Documentation/devicetree/bindings/trivial-devices.yaml
@@ -114,6 +114,12 @@ properties:
           - isil,isl68137
             # 5 Bit Programmable, Pulse-Width Modulator
           - maxim,ds1050
+            # 10-bit 8 channels 300ks/s SPI ADC with temperature sensor
+          - maxim,max1027
+            # 10-bit 12 channels 300ks/s SPI ADC with temperature sensor
+          - maxim,max1029
+            # 10-bit 16 channels 300ks/s SPI ADC with temperature sensor
+          - maxim,max1031
             # Low-Power, 4-/12-Channel, 2-Wire Serial, 12-Bit ADCs
           - maxim,max1237
             # PECI-to-I2C translator for PECI-to-SMBus/I2C protocol conversion
-- 
2.20.1

[PATCH v3 8/8] dt-bindings: Add max12xx SPI ADC series as trivial devices

[Miquel Raynal]

Update the compatible list with three Maxim ADCs compatibles.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
---
 .../bindings/iio/adc/max1027-adc.txt          | 28 +++++++++++++++++++
 .../devicetree/bindings/trivial-devices.yaml  |  6 ++++
 2 files changed, 34 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/adc/max1027-adc.txt

diff --git a/Documentation/devicetree/bindings/iio/adc/max1027-adc.txt b/Documentation/devicetree/bindings/iio/adc/max1027-adc.txt
new file mode 100644
index 000000000000..1b703a01d882
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/adc/max1027-adc.txt
@@ -0,0 +1,28 @@
+* Maxim 1027/1029/1031/1227/1229/1231 Analog to Digital Converter (ADC)
+
+Required properties:
+  - compatible: Should be one of:
+    * "maxim,max1027"
+    * "maxim,max1029"
+    * "maxim,max1031"
+    * "maxim,max1227"
+    * "maxim,max1229"
+    * "maxim,max1231"
+  - reg: SPI chip select number for the device
+
+Optional properties:
+  - interrupts: IRQ line for the ADC
+  see: Documentation/devicetree/bindings/interrupt-controller/interrupts.txt
+
+Recommended properties:
+- spi-max-frequency: Definition as per
+                     Documentation/devicetree/bindings/spi/spi-bus.txt
+
+Example:
+adc@0 {
+	compatible = "maxim,max1027";
+	reg = <0>;
+	interrupt-parent = <&gpio5>;
+	interrupts = <15 IRQ_TYPE_EDGE_RISING>;
+	spi-max-frequency = <1000000>;
+};
diff --git a/Documentation/devicetree/bindings/trivial-devices.yaml b/Documentation/devicetree/bindings/trivial-devices.yaml
index e0095ecb472f..765fd1c170df 100644
--- a/Documentation/devicetree/bindings/trivial-devices.yaml
+++ b/Documentation/devicetree/bindings/trivial-devices.yaml
@@ -120,6 +120,12 @@ properties:
           - maxim,max1029
             # 10-bit 16 channels 300ks/s SPI ADC with temperature sensor
           - maxim,max1031
+            # 12-bit 8 channels 300ks/s SPI ADC with temperature sensor
+          - maxim,max1227
+            # 12-bit 12 channels 300ks/s SPI ADC with temperature sensor
+          - maxim,max1229
+            # 12-bit 16 channels 300ks/s SPI ADC with temperature sensor
+          - maxim,max1231
             # Low-Power, 4-/12-Channel, 2-Wire Serial, 12-Bit ADCs
           - maxim,max1237
             # PECI-to-I2C translator for PECI-to-SMBus/I2C protocol conversion
-- 
2.20.1

Re: [PATCH v3 8/8] dt-bindings: Add max12xx SPI ADC series as trivial devices

[Rob Herring]

On Mon, Oct 07, 2019 at 03:26:57PM +0200, Miquel Raynal wrote:
> Update the compatible list with three Maxim ADCs compatibles.
> 
> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
> ---
>  .../bindings/iio/adc/max1027-adc.txt          | 28 +++++++++++++++++++
>  .../devicetree/bindings/trivial-devices.yaml  |  6 ++++
>  2 files changed, 34 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/iio/adc/max1027-adc.txt

Devices are supposed to be documented in one place or the other. So 
either make max1027-adc.txt a schema or drop it.

I'm fine either way. Obviously, trivial-devices.yaml is trivial to add 
to, but it does leave some ambiguities. Like is an interrupt required, 
optional or non-existent? What about power supplies? Or what are allowed 
values for spi-max-frequency.

Rob

Re: [PATCH v3 8/8] dt-bindings: Add max12xx SPI ADC series as trivial devices

[Miquel Raynal]

Hi Rob,

Rob Herring <robh@kernel.org> wrote on Thu, 10 Oct 2019 15:47:51 -0500:

> On Mon, Oct 07, 2019 at 03:26:57PM +0200, Miquel Raynal wrote:
> > Update the compatible list with three Maxim ADCs compatibles.
> > 
> > Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
> > ---
> >  .../bindings/iio/adc/max1027-adc.txt          | 28 +++++++++++++++++++
> >  .../devicetree/bindings/trivial-devices.yaml  |  6 ++++
> >  2 files changed, 34 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/iio/adc/max1027-adc.txt  
> 
> Devices are supposed to be documented in one place or the other. So 
> either make max1027-adc.txt a schema or drop it.
> 
> I'm fine either way. Obviously, trivial-devices.yaml is trivial to add 
> to, but it does leave some ambiguities. Like is an interrupt required, 
> optional or non-existent? What about power supplies? Or what are allowed 
> values for spi-max-frequency.

Rhaaa... I obviously wanted to drop the *txt file, just forgot to do
it. As the interrupts are optional I found the trivial device
description accurate enough.

Thanks,
Miquèl