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

Maxime Chevallier
2026-01-05T10:16:47Z

Hi Jonathan,

On 27/12/2025 19:42, Jonathan Cameron wrote:
> On Tue, 23 Dec 2025 16:55:33 +0100
> Maxime Chevallier <maxime.chevallier@bootlin.com> wrote:
>
>> This adds a new driver for the TI TLA2528 ADC chip. It ha 8 12-bit
>> channels, that can also be configured as 16-bit averaging channels.
>>
>> Add a very simple driver for it, allowing reading raw values for each
>> channel.
>>
>> Signed-off-by: Rodolfo Giometti <giometti@enneenne.com>
>> Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
>
> Hi Maxime,
>
> A few extra bits from me
>
> Thanks,
>
> Jonathan
>
>
>> diff --git a/drivers/iio/adc/ti-tla2528.c b/drivers/iio/adc/ti-tla2528.c
>> new file mode 100644
>> index 000000000000..9c572e730ffb
>> --- /dev/null
>> +++ b/drivers/iio/adc/ti-tla2528.c
>> @@ -0,0 +1,209 @@
>
>> +
>> +static s32 tla2528_write_reg(const struct i2c_client *client, u8 reg, u8 val)
>> +{
>> + u8 data[3] = {TLA2528_OP_WRITE_REG, reg, val};
>
> Style wise. Prefer { TLA25... val };

Sure thing, I'll address that.

>
> - couple of spaces next to the brackets.
>
>> + int ret;
>> +
>> + ret = i2c_master_send(client, data, 3);
>> +
>> + return ret < 0 ? ret : 0;
>> +}
>> +
>> +static int tla2528_read_sample(const struct i2c_client *client)
>> +{
>> + __be16 data;
>> + int ret;
>> +
>> + ret = i2c_master_recv(client, (char *)&data, 2);
>
> sizeof(data)
>
>> + if (ret < 0)
>> + return ret;
>> +
>> + return be16_to_cpu(data) >> 4;
>> +}
>
>> +
>> +#define TLA2528_CHAN(_chan, _name) { \
>
> The _ aren't adding anything here, so I'd drop them.
>
>> + .type = IIO_VOLTAGE, \
>> + .channel = (_chan), \
>> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
>> + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
>> + .datasheet_name = _name, \
>> + .indexed = 1, \
>> +}

Absolutely :)

>> +
>> +static int tla2528_probe(struct i2c_client *client)
>> +{
>> + struct iio_dev *indio_dev;
>> + struct tla2528 *tla2528;
>> + int ret;
>> +
>> + if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
>> + I2C_FUNC_SMBUS_WRITE_WORD_DATA))
>> + return -EOPNOTSUPP;
>> +
>> + indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*tla2528));
>> + if (!indio_dev)
>> + return -ENOMEM;
>> +
>> + tla2528 = iio_priv(indio_dev);
>> + i2c_set_clientdata(client, indio_dev);
>
> Ever used? If not don't set it.

David mentionned that as well, I'll drop this as this is no longer
required. It used to be required before switching to devm_ helpers.

>
>> + tla2528->client = client;
>> +
>> + indio_dev->name = client->name;
>
> Prefer to see it hard coded as a string. If we added extra firmware
> types in future the content of client->name can become something other
> than the part number.

True, I'll change that

>
>
>> + indio_dev->info = &tla2528_info;
>> + indio_dev->modes = INDIO_DIRECT_MODE;
>> + indio_dev->channels = tla2528_channel;
>> + indio_dev->num_channels = ARRAY_SIZE(tla2528_channel);
>> +
>> + mutex_init(&tla2528->lock);
>> +
>> + tla2528->vref_uv = devm_regulator_get_enable_read_voltage(&client->dev,
>> + "vref");
>> + if (tla2528->vref_uv < 0)
>> + return tla2528->vref_uv;
>> +
>> + /* Set all inputs as analog */
>> + ret = tla2528_write_reg(tla2528->client, TLA2528_PIN_CFG_ADR, 0x00);
>> + if (ret < 0)
>> + return ret;
>> +
>> + ret = tla2528_write_reg(tla2528->client, TLA2528_DATA_CFG_ADR,
>> + TLA2528_DATA_CFG_APPEND_STATUS);
>> + if (ret < 0)
>> + return ret;
>> +
>> + /* Set manual mode */
>> + ret = tla2528_write_reg(tla2528->client, TLA2528_SEQUENCE_CFG_ADR, 0x00);
>> + if (ret < 0)
>> + return ret;
>> +
>> + /* Init private data */
>> + tla2528->last_read_channel = ~0;
>> +
>> + return devm_iio_device_register(&client->dev, indio_dev);
>> +}

Thanks for the reviews :)

Maxime