linux-kernel - Re: [PATCH 1/2] iio: magnetometer: add support for Infineon TLV493D 3D Magentic sensor

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Message-ID: <20250727133852.371111bc@jic23-huawei>
Date: Sun, 27 Jul 2025 13:38:52 +0100
From: Jonathan Cameron <jic23@...nel.org>
To: David Lechner <dlechner@...libre.com>
Cc: Dixit Parmar <dixitparmar19@...il.com>, Nuno Sá
 <nuno.sa@...log.com>, Andy Shevchenko <andy@...nel.org>, Rob Herring
 <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley
 <conor+dt@...nel.org>, linux-kernel@...r.kernel.org,
 linux-iio@...r.kernel.org, devicetree@...r.kernel.org
Subject: Re: [PATCH 1/2] iio: magnetometer: add support for Infineon TLV493D
 3D Magentic sensor

On Sat, 26 Jul 2025 15:44:03 -0500
David Lechner <dlechner@...libre.com> wrote:

> On 7/26/25 4:37 AM, Dixit Parmar wrote:
> > The Infineon TLV493D is a Low-Power 3D Magnetic Sensor. The Sensor
> > applications includes joysticks, control elements (white goods,
> > multifunction knops), or electric meters (anti tampering) and any
> > other application that requires accurate angular measurements at
> > low power consumptions.
> > 
> > The Sensor is configured over I2C, and as part of Sensor measurement
> > data it provides 3-Axis magnetic fields and temperature core measurement.
> > 
> > The driver supports raw value read and buffered input via external trigger
> > to allow streaming values with the same sensing timestamp.
> > 
> > The device can be configured in to different operating modes by optional
> > device-tree "mode" property. Also, the temperature sensing part requires
> > raw offset captured at 25°C and that can be specified by "temp-offset"
> > optional device-tree property.
> > 
> > While sensor has interrupt pin multiplexed with I2C SCL pin. But for bus
> > configurations interrupt(INT) is not recommended, unless timing constraints
> > between I2C data transfers and interrupt pulses are monitored and aligned.
> > 
> > The Sensor's I2C register map and mode information is described in product
> > User Manual[1].
> > 
> > Datasheet: https://www.infineon.com/assets/row/public/documents/24/49/infineon-tlv493d-a1b6-datasheet-en.pdf
> > [1] https://www.mouser.com/pdfDocs/Infineon-TLV493D-A1B6_3DMagnetic-UserManual-v01_03-EN.pdf
> > 
> > Signed-off-by: Dixit Parmar <dixitparmar19@...il.com>

> > +static const struct regmap_config tlv493d_regmap_config = {
> > +	.reg_bits = 8,
> > +	.val_bits = 8,
> > +	.max_register = TLV493D_RD_REG_RES3,
> > +	.volatile_table = &tlv493d_volatile_regs,
> > +};
> > +
> > +static int tlv493d_probe(struct i2c_client *client)
> > +{
> > +	struct device *dev = &client->dev;
> > +	struct iio_dev *indio_dev;
> > +	struct tlv493d_data *data;
> > +	int ret;
> > +
> > +	indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
> > +	if (!indio_dev)
> > +		return -ENOMEM;
> > +
> > +	data = iio_priv(indio_dev);
> > +	data->dev = dev;
> > +	data->client = client;
> > +	i2c_set_clientdata(client, indio_dev);  
> 
> There is not i2c_get_clientdata(), so I don't think we need this.
There's a dev_get_drvdata() that pairs with this in suspend and resume.

I kind of wish the bus specific accessor would go away but there
is too much history behind them :(

> > +static int tlv493d_runtime_suspend(struct device *dev)
> > +{
> > +	struct iio_dev *indio_dev = dev_get_drvdata(dev);
> > +	struct tlv493d_data *data = iio_priv(indio_dev);
> > +
> > +	return tlv493d_set_operating_mode(data, TLV493D_OP_MODE_POWERDOWN);
> > +}
> > +
> > +static int tlv493d_runtime_resume(struct device *dev)
> > +{
> > +	struct iio_dev *indio_dev = dev_get_drvdata(dev);
> > +	struct tlv493d_data *data = iio_priv(indio_dev);
> > +
> > +	return tlv493d_set_operating_mode(data, data->mode);
> > +}
> > +
> > +static DEFINE_RUNTIME_DEV_PM_OPS(tlv493d_pm_ops,
> > +		tlv493d_runtime_suspend, tlv493d_runtime_resume, NULL);
> > +
> > +static const struct i2c_device_id tlv493d_id[] = {
> > +	{ "tlv493d" },
> > +	{ }
> > +};
> > +MODULE_DEVICE_TABLE(i2c, tlv493d_id);
> > +
> > +static const struct of_device_id tlv493d_of_match[] = {
> > +	{ .compatible = "infineon,tlv493d-a1b6", },
> > +	{ }
> > +};
> > +MODULE_DEVICE_TABLE(of, tlv493d_of_match);
> > +
> > +static struct i2c_driver tlv493d_driver = {
> > +	.driver = {
> > +		.name = "tlv493d",
> > +		.of_match_table = tlv493d_of_match,
> > +		.pm = pm_ptr(&tlv493d_pm_ops),
> > +	},
> > +	.probe = tlv493d_probe,
> > +	.id_table = tlv493d_id,
> > +};
> > +
> > +module_i2c_driver(tlv493d_driver);
> > +
> > +MODULE_LICENSE("GPL");
> > +MODULE_DESCRIPTION("Infineon TLV493D Low-Power 3D Magnetic Sensor");
> > +MODULE_AUTHOR("Dixit Parmar <dixitparmar19@...il.com>");
> >   
>