linux-kernel - Re: [PATCH v3 4/5] iio: accel: mc3230: add multiple devices support

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Message-ID: <20250112163221.4782ad53@jic23-huawei>
Date: Sun, 12 Jan 2025 16:32:21 +0000
From: Jonathan Cameron <jic23@...nel.org>
To: Vasiliy Doylov via B4 Relay
 <devnull+nekodevelopper.gmail.com@...nel.org>
Cc: nekodevelopper@...il.com, Lars-Peter Clausen <lars@...afoo.de>, Rob
 Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor
 Dooley <conor+dt@...nel.org>, linux-iio@...r.kernel.org,
 linux-kernel@...r.kernel.org, devicetree@...r.kernel.org
Subject: Re: [PATCH v3 4/5] iio: accel: mc3230: add multiple devices support

On Sun, 12 Jan 2025 15:25:38 +0300
Vasiliy Doylov via B4 Relay <devnull+nekodevelopper.gmail.com@...nel.org> wrote:

> From: Vasiliy Doylov <nekodevelopper@...il.com>
> 
> This patch allows to add new devices to this driver.
> 
> Signed-off-by: Vasiliy Doylov <nekodevelopper@...il.com>
One comment inline.

Jonathan

> ---
>  drivers/iio/accel/mc3230.c | 50 ++++++++++++++++++++++++++++++++++------------
>  1 file changed, 37 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/iio/accel/mc3230.c b/drivers/iio/accel/mc3230.c
> index ba30c904d3f67002deeb3ca5a7e12bfae312e05f..1b58f3ea50655b6563a78a2531b16a8088e8f8d5 100644
> --- a/drivers/iio/accel/mc3230.c
> +++ b/drivers/iio/accel/mc3230.c
> @@ -22,20 +22,29 @@
>  #define MC3230_MODE_OPCON_STANDBY	0x03
>  
>  #define MC3230_REG_CHIP_ID		0x18
> -#define MC3230_CHIP_ID			0x01
> -
>  #define MC3230_REG_PRODUCT_CODE		0x3b
> -#define MC3230_PRODUCT_CODE		0x19
>  
>  /*
>   * The accelerometer has one measurement range:
>   *
>   * -1.5g - +1.5g (8-bit, signed)
>   *
> - * scale = (1.5 + 1.5) * 9.81 / (2^8 - 1)	= 0.115411765
>   */
>  
> -static const int mc3230_nscale = 115411765;
> +struct mc3230_chip_info {
> +	const u8 chip_id;
> +	const char *name;
> +	const u8 product_code;

Keep chip_id and product_code together.  They are coming from
the same place and closely related fields.  Original
ordering in v1 made more sense than this.

> +	const int scale;
> +};
> +
> +static struct mc3230_chip_info mc3230_chip_info = {
> +	.chip_id = 0x01,
> +	.name = "mc3230",
> +	.product_code = 0x19,
> +	/* (1.5 + 1.5) * 9.81 / (2^8 - 1) = 0.115411765 */
> +	.scale = 115411765,
> +};
>  
>  #define MC3230_CHANNEL(reg, axis) {	\
>  	.type = IIO_ACCEL,	\
> @@ -48,6 +57,7 @@ static const int mc3230_nscale = 115411765;
>  }
>  
>  struct mc3230_data {
> +	const struct mc3230_chip_info *chip_info;
>  	struct i2c_client *client;
>  	struct iio_mount_matrix orientation;
>  };
> @@ -111,7 +121,7 @@ static int mc3230_read_raw(struct iio_dev *indio_dev,
>  		return IIO_VAL_INT;
>  	case IIO_CHAN_INFO_SCALE:
>  		*val = 0;
> -		*val2 = mc3230_nscale;
> +		*val2 = data->chip_info->scale;
>  		return IIO_VAL_INT_PLUS_NANO;
>  	default:
>  		return -EINVAL;
> @@ -127,15 +137,28 @@ static int mc3230_probe(struct i2c_client *client)
>  	int ret;
>  	struct iio_dev *indio_dev;
>  	struct mc3230_data *data;
> +	const struct mc3230_chip_info *chip_info;
> +
> +	chip_info = i2c_get_match_data(client);
> +	if (chip_info == NULL) {
> +		dev_err(&client->dev, "failed to get match data");
> +		return -ENODATA;
> +	}
>  
>  	/* First check chip-id and product-id */
>  	ret = i2c_smbus_read_byte_data(client, MC3230_REG_CHIP_ID);
> -	if (ret != MC3230_CHIP_ID)
> -		return (ret < 0) ? ret : -ENODEV;
> +	if (ret != chip_info->chip_id) {
> +		dev_info(&client->dev,
> +			"chip id check fail: 0x%x != 0x%x !\n",
> +			ret, chip_info->chip_id);
> +	}
>  
>  	ret = i2c_smbus_read_byte_data(client, MC3230_REG_PRODUCT_CODE);
> -	if (ret != MC3230_PRODUCT_CODE)
> -		return (ret < 0) ? ret : -ENODEV;
> +	if (ret != chip_info->product_code) {
> +		dev_info(&client->dev,
> +			"product code check fail: 0x%x != 0x%x !\n",
> +			ret, chip_info->product_code);
> +	}
>  
>  	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
>  	if (!indio_dev) {
> @@ -144,11 +167,12 @@ static int mc3230_probe(struct i2c_client *client)
>  	}
>  
>  	data = iio_priv(indio_dev);
> +	data->chip_info = chip_info;
>  	data->client = client;
>  	i2c_set_clientdata(client, indio_dev);
>  
>  	indio_dev->info = &mc3230_info;
> -	indio_dev->name = "mc3230";
> +	indio_dev->name = chip_info->name;
>  	indio_dev->modes = INDIO_DIRECT_MODE;
>  	indio_dev->channels = mc3230_channels;
>  	indio_dev->num_channels = ARRAY_SIZE(mc3230_channels);
> @@ -200,13 +224,13 @@ static int mc3230_resume(struct device *dev)
>  static DEFINE_SIMPLE_DEV_PM_OPS(mc3230_pm_ops, mc3230_suspend, mc3230_resume);
>  
>  static const struct i2c_device_id mc3230_i2c_id[] = {
> -	{ "mc3230" },
> +	{ "mc3230", (kernel_ulong_t)&mc3230_chip_info },
>  	{}
>  };
>  MODULE_DEVICE_TABLE(i2c, mc3230_i2c_id);
>  
>  static const struct of_device_id mc3230_of_match[] = {
> -	{ .compatible = "mcube,mc3230" },
> +	{ .compatible = "mcube,mc3230", &mc3230_chip_info },
>  	{}
>  };
>  MODULE_DEVICE_TABLE(of, mc3230_of_match);
>