[PATCH v4 0/2] iio: adc: add driver for Texas Instruments TLA2528 adc

[PATCH v4 0/2] iio: adc: add driver for Texas Instruments TLA2528 adc

[Maxime Chevallier]

Hi everyone,

This is V4 for the TI TLA2528 driver, for the ADC part. This new
revision contains a small amount of changes, after the reviews from
Joshua, Andy, Jonathan, and sashiko.

Thanks everyone for the quick feedback,

Maxime

V4:
  - Return -EIO on a short read in tla2528_read(), from Joshua
  - Drop mod_devicetable.h, include asm/byteorder.h
  - Rename vref_mv to vref_mV
  - Drop the L: entry in MAINTAINERS

V3: https://lore.kernel.org/r/20261104125726.1754980-1-maxime.chevallier@bootlin.com
  - Require channels to be described
  - Use guard()
  - Add Datasheet link
  - Drop the unused registers
  - Use named initializers in the id table
  - Collect Conor's Ack

V2: https://lore.kernel.org/r/20261030164705.297354-1-maxime.chevallier@bootlin.com
  - Describe AVDD and DVDD in the bindings instead of vref.
  - Add gpio-controller
  - Allow describing individual ADC channels
  - Switch to regmap with caching
  - Reset the chip at probe time
  - Small cleanups following all the reviews
  - Moved MAINTAINERS to patch 1

V1: https://lore.kernel.org/linux-iio/20251223155534.220504-1-maxime.chevallier@bootlin.com/

Maxime Chevallier (2):
  dt-bindings: iio: adc: add Texas Instruments TLA2528
  iio: adc: add driver for Texas Instruments TLA2528 adc

 .../bindings/iio/adc/ti,tla2528.yaml          |  91 ++++++++
 MAINTAINERS                                   |   6 +
 drivers/iio/adc/Kconfig                       |  12 +
 drivers/iio/adc/Makefile                      |   1 +
 drivers/iio/adc/ti-tla2528.c                  | 218 ++++++++++++++++++
 5 files changed, 328 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/adc/ti,tla2528.yaml
 create mode 100644 drivers/iio/adc/ti-tla2528.c

-- 
2.56.0

[PATCH v4 1/2] dt-bindings: iio: adc: add Texas Instruments TLA2528

[Maxime Chevallier]

The TI TLA2528 is a simple 8-channel, 12-bit ADC and GPIO chip
accessible over i2c. The ADC part has an AVDD supply that doubles as a
reference.

Acked-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
---
 .../bindings/iio/adc/ti,tla2528.yaml          | 91 +++++++++++++++++++
 MAINTAINERS                                   |  5 +
 2 files changed, 96 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/adc/ti,tla2528.yaml

diff --git a/Documentation/devicetree/bindings/iio/adc/ti,tla2528.yaml b/Documentation/devicetree/bindings/iio/adc/ti,tla2528.yaml
new file mode 100644
index 000000000000..7a50a5026c1e
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/adc/ti,tla2528.yaml
@@ -0,0 +1,91 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/adc/ti,tla2528.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Texas Instruments TLA2528 8-channel 12-bit I2C ADC
+
+maintainers:
+  - Maxime Chevallier <maxime.chevallier@bootlin.com>
+
+description:
+  Each of the 8 input pins can be configured as an analog input, a digital
+  input or a digital output.
+
+properties:
+  compatible:
+    const: ti,tla2528
+
+  reg:
+    maxItems: 1
+
+  avdd-supply:
+    description: Analog supply, also used as the ADC reference voltage.
+
+  dvdd-supply: true
+
+  gpio-controller: true
+
+  "#gpio-cells":
+    const: 2
+
+  "#io-channel-cells":
+    const: 1
+
+  "#address-cells":
+    const: 1
+
+  "#size-cells":
+    const: 0
+
+patternProperties:
+  "^channel@[0-7]$":
+    type: object
+    $ref: adc.yaml
+    description: Represents an analog input.
+
+    properties:
+      reg:
+        description: AIN pin number
+        minimum: 0
+        maximum: 7
+
+    required:
+      - reg
+
+    unevaluatedProperties: false
+
+required:
+  - compatible
+  - reg
+  - avdd-supply
+  - dvdd-supply
+
+additionalProperties: false
+
+examples:
+  - |
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        adc@17 {
+            compatible = "ti,tla2528";
+            reg = <0x17>;
+            avdd-supply = <&reg_adc_supply>;
+            dvdd-supply = <&reg_adc_supply>;
+            #io-channel-cells = <1>;
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            channel@0 {
+                reg = <0>;
+            };
+
+            channel@3 {
+                reg = <3>;
+            };
+        };
+    };
+...
diff --git a/MAINTAINERS b/MAINTAINERS
index 93abbb315065..2cf3fc9bb74d 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -27758,6 +27758,11 @@ F:	include/dt-bindings/soc/ti,sci_pm_domain.h
 F:	include/linux/soc/ti/ti_sci_inta_msi.h
 F:	include/linux/soc/ti/ti_sci_protocol.h
 
+TEXAS INSTRUMENTS' TLA2528 ADC DRIVER
+M:	Maxime Chevallier <maxime.chevallier@bootlin.com>
+S:	Supported
+F:	Documentation/devicetree/bindings/iio/adc/ti,tla2528.yaml
+
 TEXAS INSTRUMENTS' TMP117 TEMPERATURE SENSOR DRIVER
 M:	Puranjay Mohan <puranjay@kernel.org>
 L:	linux-iio@vger.kernel.org
-- 
2.56.0

[PATCH v4 2/2] iio: adc: add driver for Texas Instruments TLA2528 adc

[Maxime Chevallier]

Add a new driver for the TI TLA2528 ADC chip. It has 8 12-bit
channels, that can also be configured as 16-bit averaging channels.

This is a very simple driver, allowing reading raw values for each
channel. GPIO mode isn't supported for now, as well as buffered mode and
the 16-bit averaging mode.

Co-developed-by: Rodolfo Giometti <giometti@enneenne.com>
Signed-off-by: Rodolfo Giometti <giometti@enneenne.com>
Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
---
 MAINTAINERS                  |   1 +
 drivers/iio/adc/Kconfig      |  12 ++
 drivers/iio/adc/Makefile     |   1 +
 drivers/iio/adc/ti-tla2528.c | 218 +++++++++++++++++++++++++++++++++++
 4 files changed, 232 insertions(+)
 create mode 100644 drivers/iio/adc/ti-tla2528.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 2cf3fc9bb74d..59e960d7e547 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -27762,6 +27762,7 @@ TEXAS INSTRUMENTS' TLA2528 ADC DRIVER
 M:	Maxime Chevallier <maxime.chevallier@bootlin.com>
 S:	Supported
 F:	Documentation/devicetree/bindings/iio/adc/ti,tla2528.yaml
+F:	drivers/iio/adc/ti-tla2528.c
 
 TEXAS INSTRUMENTS' TMP117 TEMPERATURE SENSOR DRIVER
 M:	Puranjay Mohan <puranjay@kernel.org>
diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index a802d8ee4dd9..8633267d6056 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -2016,6 +2016,18 @@ config TI_LMP92064
 	  This driver can also be built as a module. If so, the module will be called
 	  ti-lmp92064.
 
+config TI_TLA2528
+	tristate "Texas Instruments TLA2528 ADC driver"
+	depends on I2C
+	select REGMAP_I2C
+	select IIO_ADC_HELPER
+	help
+	  Say yes here to build support for Texas Instruments TLA2528
+	  12-Bit 8-Channel ADC.
+
+	  To compile this driver as a module, choose M here: the module will be
+	  called ti-tla2528.
+
 config TI_TLC4541
 	tristate "Texas Instruments TLC4541 ADC driver"
 	depends on SPI
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index 9e82c21dbd37..b98cded4d0c7 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -171,6 +171,7 @@ obj-$(CONFIG_TI_ADS8344) += ti-ads8344.o
 obj-$(CONFIG_TI_ADS8688) += ti-ads8688.o
 obj-$(CONFIG_TI_AM335X_ADC) += ti_am335x_adc.o
 obj-$(CONFIG_TI_LMP92064) += ti-lmp92064.o
+obj-$(CONFIG_TI_TLA2528) += ti-tla2528.o
 obj-$(CONFIG_TI_TLC4541) += ti-tlc4541.o
 obj-$(CONFIG_TI_TSC2046) += ti-tsc2046.o
 obj-$(CONFIG_TWL4030_MADC) += twl4030-madc.o
diff --git a/drivers/iio/adc/ti-tla2528.c b/drivers/iio/adc/ti-tla2528.c
new file mode 100644
index 000000000000..c02b04e19785
--- /dev/null
+++ b/drivers/iio/adc/ti-tla2528.c
@@ -0,0 +1,218 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Driver for Texas Instruments TLA2528 ADC
+ *
+ * Copyright (C) 2020-2021 Rodolfo Giometti <giometti@enneenne.com>
+ * Copyright (C) 2025 Maxime Chevallier <maxime.chevallier@bootlin.com>
+ * Datasheet: https://www.ti.com/lit/gpn/tla2528
+ */
+
+#include <linux/bits.h>
+#include <linux/cleanup.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+#include <linux/types.h>
+#include <linux/units.h>
+
+#include <asm/byteorder.h>
+
+#include <linux/iio/adc-helpers.h>
+#include <linux/iio/iio.h>
+
+#define TLA2528_OP_WRITE_REG		0x08
+#define TLA2528_OP_READ_REG		0x10
+
+#define TLA2528_GENERAL_CFG_ADR		0x01
+#define TLA2528_GENERAL_CFG_RST		BIT(0)
+#define TLA2528_CHANNEL_SEL_ADR		0x11
+#define TLA2528_CHANNEL_SEL_MANUAL_CHID	GENMASK(3, 0)
+#define TLA2528_AUTO_SEQ_CH_SEL_ADR	0x12
+
+#define TLA2528_NUM_CHANNELS		8
+
+struct tla2528 {
+	struct i2c_client *client;
+	struct regmap *regmap;
+	int vref_mV;
+
+	/* Protects manual channel selection */
+	struct mutex lock;
+};
+
+static bool tla2528_volatile_reg(struct device *dev, unsigned int reg)
+{
+	return reg == TLA2528_GENERAL_CFG_ADR;
+}
+
+static const struct regmap_config tla2528_regmap_config = {
+	.reg_bits = 16,
+	.val_bits = 8,
+	.read_flag_mask = TLA2528_OP_READ_REG,
+	.write_flag_mask = TLA2528_OP_WRITE_REG,
+	.max_register = TLA2528_AUTO_SEQ_CH_SEL_ADR,
+	.volatile_reg = tla2528_volatile_reg,
+	.cache_type = REGCACHE_MAPLE,
+};
+
+static int tla2528_read(struct tla2528 *tla2528, u8 channel, int *val)
+{
+	__be16 data;
+	int ret;
+
+	guard(mutex)(&tla2528->lock);
+
+	ret = regmap_update_bits(tla2528->regmap, TLA2528_CHANNEL_SEL_ADR,
+				 TLA2528_CHANNEL_SEL_MANUAL_CHID, channel);
+	if (ret)
+		return ret;
+
+	ret = i2c_master_recv(tla2528->client, (char *)&data, sizeof(data));
+	if (ret < 0)
+		return ret;
+	if (ret != sizeof(data))
+		return -EIO;
+
+	*val = be16_to_cpu(data) >> 4;
+
+	return 0;
+}
+
+static int tla2528_read_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan,
+			    int *val, int *val2, long mask)
+{
+	struct tla2528 *tla2528 = iio_priv(indio_dev);
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		ret = tla2528_read(tla2528, chan->channel, val);
+		if (ret < 0)
+			return ret;
+
+		return IIO_VAL_INT;
+
+	case IIO_CHAN_INFO_SCALE:
+		*val = tla2528->vref_mV;
+		*val2 = 12;
+
+		return IIO_VAL_FRACTIONAL_LOG2;
+
+	default:
+		return -EINVAL;
+	}
+}
+
+#define TLA2528_CHAN(chan) {					\
+	.type = IIO_VOLTAGE,					\
+	.channel = (chan),					\
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
+	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
+	.indexed = 1,						\
+}
+
+static const struct iio_chan_spec tla2528_chan_template = TLA2528_CHAN(0);
+
+static const struct iio_info tla2528_info = {
+	.read_raw = tla2528_read_raw,
+};
+
+static int tla2528_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct iio_chan_spec *channels;
+	struct iio_dev *indio_dev;
+	struct tla2528 *tla2528;
+	int ret;
+
+	/*
+	 * We're reading the data with raw i2c reads, without passing an
+	 * address like we would for smbus-style accesses.
+	 */
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
+		return -EOPNOTSUPP;
+
+	if (i2c_check_quirks(client->adapter, I2C_AQ_NO_CLK_STRETCH))
+		return dev_err_probe(dev, -EOPNOTSUPP,
+				     "adapter does not support clock stretching\n");
+
+	indio_dev = devm_iio_device_alloc(dev, sizeof(*tla2528));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	tla2528 = iio_priv(indio_dev);
+	tla2528->client = client;
+
+	tla2528->regmap = devm_regmap_init_i2c(client, &tla2528_regmap_config);
+	if (IS_ERR(tla2528->regmap))
+		return PTR_ERR(tla2528->regmap);
+
+	ret = devm_mutex_init(dev, &tla2528->lock);
+	if (ret)
+		return ret;
+
+	ret = devm_regulator_get_enable(dev, "dvdd");
+	if (ret)
+		return ret;
+
+	ret = devm_regulator_get_enable_read_voltage(dev, "avdd");
+	if (ret < 0)
+		return ret;
+
+	tla2528->vref_mV = ret / (MICRO / MILLI);
+
+	ret = devm_iio_adc_device_alloc_chaninfo_se(dev, &tla2528_chan_template,
+						    TLA2528_NUM_CHANNELS - 1,
+						    &channels);
+	if (ret < 0)
+		return dev_err_probe(dev, ret, "failed to get ADC channels\n");
+
+	indio_dev->channels = channels;
+	indio_dev->num_channels = ret;
+
+	indio_dev->name = "tla2528";
+	indio_dev->info = &tla2528_info;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+
+	ret = regmap_write(tla2528->regmap, TLA2528_GENERAL_CFG_ADR,
+			   TLA2528_GENERAL_CFG_RST);
+	if (ret)
+		return ret;
+
+	fsleep(5 * USEC_PER_MSEC);
+
+	return devm_iio_device_register(dev, indio_dev);
+}
+
+static const struct i2c_device_id tla2528_id[] = {
+	{ .name = "tla2528" },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, tla2528_id);
+
+static const struct of_device_id tla2528_of_match[] = {
+	{ .compatible = "ti,tla2528" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, tla2528_of_match);
+
+static struct i2c_driver tla2528_driver = {
+	.driver = {
+		.name = "tla2528",
+		.of_match_table = tla2528_of_match,
+	},
+	.probe = tla2528_probe,
+	.id_table = tla2528_id,
+};
+module_i2c_driver(tla2528_driver);
+
+MODULE_AUTHOR("Maxime Chevallier <maxime.chevallier@bootlin.com>");
+MODULE_AUTHOR("Rodolfo Giometti <giometti@enneenne.com>");
+MODULE_DESCRIPTION("Texas Instruments TLA2528 ADC driver");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS("IIO_DRIVER");
-- 
2.56.0

Re: [PATCH v4 2/2] iio: adc: add driver for Texas Instruments TLA2528 adc

[Joshua Crofts]

On Fri, 13 Nov 2026 16:15:42 +0100
Maxime Chevallier <maxime.chevallier@bootlin.com> wrote:

> Add a new driver for the TI TLA2528 ADC chip. It has 8 12-bit
> channels, that can also be configured as 16-bit averaging channels.
> 
> This is a very simple driver, allowing reading raw values for each
> channel. GPIO mode isn't supported for now, as well as buffered mode and
> the 16-bit averaging mode.
> 
> Co-developed-by: Rodolfo Giometti <giometti@enneenne.com>
> Signed-off-by: Rodolfo Giometti <giometti@enneenne.com>
> Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
> ---

This looks ready to be applied.

Reviewed-by: Joshua Crofts <crofts@kernel.org>

-- 
Kind regards,
Joshua Crofts

Re: [PATCH v4 2/2] iio: adc: add driver for Texas Instruments TLA2528 adc

[Matti Vaittinen]

On 13/11/2026 17:15, Maxime Chevallier wrote:
> Add a new driver for the TI TLA2528 ADC chip. It has 8 12-bit
> channels, that can also be configured as 16-bit averaging channels.
> 
> This is a very simple driver, allowing reading raw values for each
> channel. GPIO mode isn't supported for now, as well as buffered mode and
> the 16-bit averaging mode.
> 
> Co-developed-by: Rodolfo Giometti <giometti@enneenne.com>
> Signed-off-by: Rodolfo Giometti <giometti@enneenne.com>
> Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
This looks very familiar to me. I am pretty sure I've reviewed this. Is 
there a reason the RB-tag wasn't carried over? (Sorry if I've missed 
some change(s))!

Yours,
   -- Matti

-- 
Matti Vaittinen
Linux kernel developer at ROHM Semiconductors
Oulu Finland

~~ When things go utterly wrong vim users can always type :help! ~~

Re: [PATCH v4 2/2] iio: adc: add driver for Texas Instruments TLA2528 adc

[Andy Shevchenko]

On Fri, Nov 13, 2026 at 04:15:42PM +0100, Maxime Chevallier wrote:
> Add a new driver for the TI TLA2528 ADC chip. It has 8 12-bit
> channels, that can also be configured as 16-bit averaging channels.

I forgot to check if there is a justification of the brand new driver,
I assume there is.

> This is a very simple driver, allowing reading raw values for each
> channel. GPIO mode isn't supported for now, as well as buffered mode and
> the 16-bit averaging mode.

Some nit-picks below, but they do not prevent from this patch being accepted,
so

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

...

> +static int tla2528_read(struct tla2528 *tla2528, u8 channel, int *val)
> +{
> +	__be16 data;
> +	int ret;
> +
> +	guard(mutex)(&tla2528->lock);
> +
> +	ret = regmap_update_bits(tla2528->regmap, TLA2528_CHANNEL_SEL_ADR,
> +				 TLA2528_CHANNEL_SEL_MANUAL_CHID, channel);
> +	if (ret)
> +		return ret;

Ideally this needs a comment explaining in short why regmap IO accessors may
not be used.

> +	ret = i2c_master_recv(tla2528->client, (char *)&data, sizeof(data));
> +	if (ret < 0)
> +		return ret;
> +	if (ret != sizeof(data))
> +		return -EIO;
> +
> +	*val = be16_to_cpu(data) >> 4;
> +
> +	return 0;
> +}

...

> +	ret = regmap_write(tla2528->regmap, TLA2528_GENERAL_CFG_ADR,
> +			   TLA2528_GENERAL_CFG_RST);

With locally defined

	struct regmap *map;
	...
	map = devm_regmap_*init*(...);
	...
	tla2528->regmap = map;
	...
	ret = regmap_write(map, TLA2528_GENERAL_CFG_ADR, TLA2528_GENERAL_CFG_RST);

this can kill two birds with one stone:
- make this one line (yes, 82 characters is okay)
- keeping data structure free from error pointers

> +	if (ret)
> +		return ret;

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v4 2/2] iio: adc: add driver for Texas Instruments TLA2528 adc

[Maxime Chevallier]

Hi Matti,

On 11/13/26 16:36, Matti Vaittinen wrote:
> On 13/11/2026 17:15, Maxime Chevallier wrote:
>> Add a new driver for the TI TLA2528 ADC chip. It has 8 12-bit
>> channels, that can also be configured as 16-bit averaging channels.
>>
>> This is a very simple driver, allowing reading raw values for each
>> channel. GPIO mode isn't supported for now, as well as buffered mode and
>> the 16-bit averaging mode.
>>
>> Co-developed-by: Rodolfo Giometti <giometti@enneenne.com>
>> Signed-off-by: Rodolfo Giometti <giometti@enneenne.com>
>> Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
> This looks very familiar to me. I am pretty sure I've reviewed this. Is there a reason the RB-tag wasn't carried over? (Sorry if I've missed some change(s))!
> 
> Yours,
>   -- Matti

You did add a Rb tag on V2, but I dropped it for V3 as the delta between V2
and V3 was quite substantial and included changes requested by other people
than you :)

I mentionned your tag being dropped on the V3 cover, but I didn't carry that info
for V4, sorry about that...

Anyways thanks a lot for the help,

Maxime