linux-kernel - Re: [PATCH v4 2/3] iio: pressure: Add driver for Sensirion SDP500

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Message-ID: <20240728162828.3c9cc118@jic23-huawei>
Date: Sun, 28 Jul 2024 16:28:28 +0100
From: Jonathan Cameron <jic23@...nel.org>
To: Petar Stoykov via B4 Relay <devnull+pd.pstoykov.gmail.com@...nel.org>
Cc: pd.pstoykov@...il.com, linux-iio@...r.kernel.org, Lars-Peter Clausen
 <lars@...afoo.de>, Rob Herring <robh+dt@...nel.org>, Krzysztof Kozlowski
 <krzysztof.kozlowski+dt@...aro.org>, Conor Dooley <conor+dt@...nel.org>,
 Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
 devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 2/3] iio: pressure: Add driver for Sensirion SDP500

On Thu, 25 Jul 2024 17:37:28 +0200
Petar Stoykov via B4 Relay <devnull+pd.pstoykov.gmail.com@...nel.org> wrote:

> From: Petar Stoykov <pd.pstoykov@...il.com>
> 
> Sensirion SDP500 is a digital differential pressure sensor. The sensor is
> accessed over I2C.
> 
> Signed-off-by: Petar Stoykov <pd.pstoykov@...il.com>
Hi Petar,

Some really trivial things inline + Krzysztof's comment.

Rather than go around again, I'll tidy them up as follows and apply this series
to the testing branch of iio.git

Thanks,

Jonathan


diff --git a/drivers/iio/pressure/sdp500.c b/drivers/iio/pressure/sdp500.c
index 77d7e68f5dea..6ff32e3fa637 100644
--- a/drivers/iio/pressure/sdp500.c
+++ b/drivers/iio/pressure/sdp500.c
@@ -62,7 +62,7 @@ static int sdp500_read_raw(struct iio_dev *indio_dev,
 
                received_crc = rxbuf[2];
                calculated_crc = crc8(sdp500_crc8_table, rxbuf,
-                       sizeof(rxbuf) - 1, 0x00);
+                                     sizeof(rxbuf) - 1, 0x00);
                if (received_crc != calculated_crc) {
                        dev_err(data->dev,
                                "calculated crc = 0x%.2X, received 0x%.2X",
@@ -123,7 +123,7 @@ static int sdp500_probe(struct i2c_client *client)
        i2c_master_recv(client, rxbuf, SDP500_READ_SIZE);
 
        ret = devm_iio_device_register(dev, indio_dev);
-       if (ret < 0)
+       if (ret)
                return dev_err_probe(dev, ret, "Failed to register indio_dev");
 
        return 0;
@@ -137,7 +137,6 @@ MODULE_DEVICE_TABLE(i2c, sdp500_id);
 
 static const struct of_device_id sdp500_of_match[] = {
        { .compatible = "sensirion,sdp500" },
-       { .compatible = "sensirion,sdp510" },
        { }
 };
 MODULE_DEVICE_TABLE(of, sdp500_of_match);

>  st_pressure-$(CONFIG_IIO_BUFFER) += st_pressure_buffer.o
> diff --git a/drivers/iio/pressure/sdp500.c b/drivers/iio/pressure/sdp500.c
> new file mode 100644
> index 000000000000..77d7e68f5dea
> --- /dev/null
> +++ b/drivers/iio/pressure/sdp500.c
> @@ -0,0 +1,157 @@
...

> +
> +static int sdp500_read_raw(struct iio_dev *indio_dev,
> +			  struct iio_chan_spec const *chan,
> +			  int *val, int *val2, long mask)
> +{
> +	int ret;
> +	u8 rxbuf[SDP500_READ_SIZE];
> +	u8 received_crc, calculated_crc;
> +	struct sdp500_data *data = iio_priv(indio_dev);
> +	struct i2c_client *client = to_i2c_client(data->dev);
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_RAW:
> +		ret = i2c_master_recv(client, rxbuf, SDP500_READ_SIZE);
> +		if (ret < 0) {
> +			dev_err(data->dev, "Failed to receive data");
> +			return ret;
> +		}
> +		if (ret != SDP500_READ_SIZE) {
> +			dev_err(data->dev, "Data is received wrongly");
> +			return -EIO;
> +		}
> +
> +		received_crc = rxbuf[2];
> +		calculated_crc = crc8(sdp500_crc8_table, rxbuf,
> +			sizeof(rxbuf) - 1, 0x00);

align just after (

> +		if (received_crc != calculated_crc) {
> +			dev_err(data->dev,
> +				"calculated crc = 0x%.2X, received 0x%.2X",
> +				calculated_crc, received_crc);
> +			return -EIO;
> +		}
> +
> +		*val = get_unaligned_be16(rxbuf);
> +		return IIO_VAL_INT;
> +	case IIO_CHAN_INFO_SCALE:
> +		*val = 1;
> +		*val2 = 60;
> +
> +		return IIO_VAL_FRACTIONAL;
> +	default:
> +		return -EINVAL;
> +	}
> +}
> +
> +static const struct iio_info sdp500_info = {
> +	.read_raw = &sdp500_read_raw,
> +};
> +
> +static int sdp500_probe(struct i2c_client *client)
> +{
> +	struct iio_dev *indio_dev;
> +	struct sdp500_data *data;
> +	struct device *dev = &client->dev;
> +	int ret;
> +	u8 rxbuf[SDP500_READ_SIZE];
> +
> +	ret = devm_regulator_get_enable(dev, "vdd");
> +	if (ret)
> +		return dev_err_probe(dev, ret,
> +			"Failed to get and enable regulator\n");
> +
> +	indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
> +	if (!indio_dev)
> +		return -ENOMEM;
> +
> +	/* has to be done before the first i2c communication */
> +	crc8_populate_msb(sdp500_crc8_table, SDP500_CRC8_POLYNOMIAL);
> +
> +	data = iio_priv(indio_dev);
> +	data->dev = dev;
> +
> +	indio_dev->name = "sdp500";
> +	indio_dev->channels = sdp500_channels;
> +	indio_dev->info = &sdp500_info;
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +	indio_dev->num_channels = ARRAY_SIZE(sdp500_channels);
> +
> +	ret = sdp500_start_measurement(data);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "Failed to start measurement");
> +
> +	/* First measurement is not correct, read it out to get rid of it */
> +	i2c_master_recv(client, rxbuf, SDP500_READ_SIZE);
> +
> +	ret = devm_iio_device_register(dev, indio_dev);
> +	if (ret < 0)
if (ret) is more consistent with other handling in the driver (and my preference
in general for checking IIO core code calls).

> +		return dev_err_probe(dev, ret, "Failed to register indio_dev");
> +
> +	return 0;
> +}