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

Jonathan Cameron
2025-12-27T18:42:17Z

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 };

- 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, \
> +}

> +
> +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.

> + 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.

> + 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);
> +}