linux-kernel - Re: [PATCH v6 2/2] iio: magnetometer: add support for Infineon TLV493D 3D Magentic sensor

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Message-ID: <20250907104917.5d743db3@jic23-huawei>
Date: Sun, 7 Sep 2025 10:49:17 +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 v6 2/2] iio: magnetometer: add support for Infineon
 TLV493D 3D Magentic sensor

On Sat, 06 Sep 2025 14:07:57 +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>

Only thing I spotted was trivial enough that I'll tidy that up (and Andy's comment)
whilst applying.  Changes made follow.  Applied to the togreg branch of iio.git and
pushed out as testing for 0-day to take a first look at it.

diff --git a/drivers/iio/magnetometer/tlv493d.c b/drivers/iio/magnetometer/tlv493d.c
index 6b9012889148..ec53fd40277b 100644
--- a/drivers/iio/magnetometer/tlv493d.c
+++ b/drivers/iio/magnetometer/tlv493d.c
@@ -250,10 +250,8 @@ static int tlv493d_init(struct tlv493d_data *data)
         * 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;
-       }
+       if (ret < 0)
+               return dev_err_probe(dev, ret, "i2c read failed\n");
 
        /* Write register 0x0 is reserved. Does not require to be updated.*/
        data->wr_regs[0] = 0;
@@ -262,10 +260,8 @@ static int tlv493d_init(struct tlv493d_data *data)
        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;
-       }
+       if (ret < 0)
+               return dev_err_probe(dev, ret, "failed to set operating mode\n");
 
        return 0;
 }
@@ -336,7 +332,6 @@ static int tlv493d_read_raw(struct iio_dev *indio_dev,
                default:
                        return -EINVAL;
                }
-
        default:
                return -EINVAL;
        }


> diff --git a/drivers/iio/magnetometer/tlv493d.c b/drivers/iio/magnetometer/tlv493d.c
> new file mode 100644
> index 000000000000..6b9012889148
> --- /dev/null
> +++ b/drivers/iio/magnetometer/tlv493d.c

> +static int tlv493d_init(struct tlv493d_data *data)

As this is only called from probe, ideally would just dev_err_probe() for
all error message print.

> +{
> +	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;
> +}
>