linux-kernel - Re: [PATCH v4 1/2] iio: magnetometer: add support for Infineon TLV493D 3D Magentic sensor

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Message-ID: <20250816140448.37f38d0f@jic23-huawei>
Date: Sat, 16 Aug 2025 14:04:48 +0100
From: Jonathan Cameron <jic23@...nel.org>
To: Dixit Parmar <dixitparmar19@...il.com>
Cc: David Lechner <dlechner@...libre.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 v4 1/2] iio: magnetometer: add support for Infineon
 TLV493D 3D Magentic sensor

On Thu, 14 Aug 2025 08:23:43 +0530
Dixit Parmar <dixitparmar19@...il.com> 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.
> 
> While the sensor has an interrupt pin multiplexed with an 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
> Link: https://www.mouser.com/pdfDocs/Infineon-TLV493D-A1B6_3DMagnetic-UserManual-v01_03-EN.pdf [1]
> Signed-off-by: Dixit Parmar <dixitparmar19@...il.com>

Hi Dixit,

A couple of really minor things inline. Given Andy has been doing most of the review
work on this one I'll leave it for a few days to give him chance for a final look.

The stuff below is small so if nothing else comes up I can tweak it whilst applying

Thanks,

Jonathan

> diff --git a/drivers/iio/magnetometer/tlv493d.c b/drivers/iio/magnetometer/tlv493d.c
> new file mode 100644
> index 000000000000..ee72211576a6
> --- /dev/null
> +++ b/drivers/iio/magnetometer/tlv493d.c
> @@ -0,0 +1,530 @@

> +	TLV493D_AXIS_X,
> +	TLV493D_AXIS_Y,
> +	TLV493D_AXIS_Z,
> +	TLV493D_TEMPERATURE
As below.

> +};
> +
> +enum tlv493d_op_mode {
> +	TLV493D_OP_MODE_POWERDOWN,
> +	TLV493D_OP_MODE_FAST,
> +	TLV493D_OP_MODE_LOWPOWER,
> +	TLV493D_OP_MODE_ULTRA_LOWPOWER,
> +	TLV493D_OP_MODE_MASTERCONTROLLED
This is not a terminating entry, so would typically have a trailing comma.
> +};

> +
> +static int tlv493d_init(struct tlv493d_data *data)

I think this is only called from probe, so it would be appropriate
to use return dev_err_probe() in all the error paths.

If nothing else comes up I might tweak that whilst applying.

> +{
> +	int ret;
> +	u8 buff[TLV493D_RD_REG_MAX];
> +	struct device *dev = &data->client->dev;
> +
> +	/*
> +	 * The sensor initialization requires below steps to be followed,
> +	 * 1. Power-up sensor.
> +	 * 2. Read and store read-registers map (0x0-0x9).
> +	 * 3. Copy values from read reserved registers to write reserved fields (0x0-0x3).
> +	 * 4. Set operating mode.
> +	 * 5. Write to all registers.
> +	 */
> +	ret = i2c_master_recv(data->client, buff, ARRAY_SIZE(buff));
> +	if (ret < 0) {
> +		dev_err(dev, "i2c read failed, error %d\n", ret);
> +		return ret;
> +	}
> +
> +	/* Write register 0x0 is reserved. Does not require to be updated.*/
> +	data->wr_regs[0] = 0;
> +	data->wr_regs[1] = buff[TLV493D_RD_REG_RES1] & TLV493D_RD_REG_RES1_WR_MASK;
> +	data->wr_regs[2] = buff[TLV493D_RD_REG_RES2] & TLV493D_RD_REG_RES2_WR_MASK;
> +	data->wr_regs[3] = buff[TLV493D_RD_REG_RES3] & TLV493D_RD_REG_RES3_WR_MASK;
> +
> +	ret = tlv493d_set_operating_mode(data, data->mode);
> +	if (ret < 0) {
> +		dev_err(dev, "failed to set operating mode\n");
> +		return ret;
> +	}
> +
> +	return 0;
> +}