linux-kernel - Re: [PATCH 2/2] iio: humidity: Add support for ENS21x

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Message-ID: <3828472d-b0ec-4629-a844-d2fb81bc31a8@kernel.org>
Date: Wed, 10 Jul 2024 12:12:06 +0200
From: Krzysztof Kozlowski <krzk@...nel.org>
To: Joshua Felmeden <jfelmeden@...goodpenguin.co.uk>,
 Jonathan Cameron <jic23@...nel.org>, Lars-Peter Clausen <lars@...afoo.de>,
 Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>,
 Conor Dooley <conor+dt@...nel.org>
Cc: linux-iio@...r.kernel.org, devicetree@...r.kernel.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] iio: humidity: Add support for ENS21x

On 09/07/2024 18:36, Joshua Felmeden wrote:
> Add support for ENS210/ENS210A/ENS211/ENS212/ENS213A/ENS215.
> 
> The ENS21x is a family of temperature and relative humidity sensors with
> accuracies tailored to the needs of specific applications.
> 
> Signed-off-by: Joshua Felmeden <jfelmeden@...goodpenguin.co.uk>
> ---
>  drivers/iio/humidity/Kconfig  |  11 ++
>  drivers/iio/humidity/Makefile |   1 +
>  drivers/iio/humidity/ens21x.c | 348 ++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 360 insertions(+)
> 


> +
> +static int ens21x_probe(struct i2c_client *client)
> +{
> +	const struct i2c_device_id *id = i2c_client_get_device_id(client);
> +	const struct of_device_id *match;
> +	struct ens21x_dev *dev_data;
> +	struct iio_dev *indio_dev;
> +	uint16_t part_id_le, part_id;
> +	int ret, tries;
> +
> +	if (!i2c_check_functionality(client->adapter,
> +			I2C_FUNC_SMBUS_WRITE_BYTE_DATA |
> +			I2C_FUNC_SMBUS_WRITE_BYTE |
> +			I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
> +		dev_err(&client->dev,
> +			"adapter does not support some i2c transactions\n");
> +		return -EOPNOTSUPP;
> +	}
> +
> +	match = of_match_device(ens21x_of_match, &client->dev);
> +	if (!match) {
> +		dev_err(&client->dev, "failed to get match data\n");

That's odd. This should never happen, so printing error suggests
something is odd in your driver.

There is anyway helper for getting match data from i2c/of cases.


> +		return -ENODEV;
> +	}
> +
> +	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*dev_data));
> +	if (!indio_dev)
> +		return -ENOMEM;
> +
> +	dev_data = iio_priv(indio_dev);
> +	i2c_set_clientdata(client, indio_dev);
> +	dev_data->client = client;
> +	mutex_init(&dev_data->lock);
> +
> +	/* reset device */
> +	ret = i2c_smbus_write_byte_data(client, ENS21X_REG_SYS_CTRL,
> +					ENS21X_SYS_CTRL_SYS_RESET);
> +	if (ret)
> +		return ret;
> +
> +	/* wait for device to become active */
> +	usleep_range(4000, 5000);
> +
> +	/* disable low power mode */
> +	ret = i2c_smbus_write_byte_data(client, ENS21X_REG_SYS_CTRL, 0x00);
> +	if (ret)
> +		return ret;
> +
> +	/* wait for device to become active */
> +	tries = 10;
> +	while (tries-- > 0) {
> +		msleep(20);
> +		ret = i2c_smbus_read_byte_data(client, ENS21X_REG_SYS_STAT);
> +		if (ret < 0)
> +			return ret;
> +		if (ret & ENS21X_SYS_STAT_SYS_ACTIVE)
> +			break;
> +	}
> +	if (tries < 0) {
> +		dev_err(&client->dev,
> +			"timeout waiting for ens21x to become active\n");
> +		return -EIO;
> +	}
> +
> +	/* get part_id */
> +	part_id_le = i2c_smbus_read_word_data(client, ENS21X_REG_PART_ID);
> +	if (part_id_le < 0)
> +		return part_id_le;
> +	part_id = le16_to_cpu(part_id_le);
> +
> +	if (part_id != id->driver_data) {
> +		dev_err(&client->dev,
> +			"Part ID does not match (0x%04x != 0x%04lx)\n", part_id,
> +			id->driver_data);
> +		return -ENODEV;
> +	}
> +
> +	/* reenable low power */
> +	ret = i2c_smbus_write_byte_data(client, ENS21X_REG_SYS_CTRL,
> +					ENS21X_SYS_CTRL_LOW_POWER_ENABLE);
> +	if (ret)
> +		return ret;
> +
> +	dev_data->part_id = part_id;
> +
> +	indio_dev->name = id->name;
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +	indio_dev->channels = ens21x_channels;
> +	indio_dev->num_channels = ARRAY_SIZE(ens21x_channels);
> +	indio_dev->info = &ens21x_info;
> +
> +	return devm_iio_device_register(&client->dev, indio_dev);
> +}
> +
> +
> +static const struct of_device_id ens21x_of_match[] = {
> +	{ .compatible = "sciosense,ens210" },
> +	{ .compatible = "sciosense,ens210a" },
> +	{ .compatible = "sciosense,ens211" },
> +	{ .compatible = "sciosense,ens212" },
> +	{ .compatible = "sciosense,ens213a" },
> +	{ .compatible = "sciosense,ens215" },

Mismathed with i2c_device_id. These should have the same data. Also,
keep the tables next to each other (here).



Best regards,
Krzysztof