Re: [PATCH v4 6/9] platform/x86: bus-multi-instantiate: Reorganize I2C functions

[Hans de Goede]

Hi,

Sorry some more remarks after all...

On 1/20/22 14:43, Stefan Binding wrote:
> From: Lucas Tanure <tanureal@xxxxxxxxxxxxxxxxxxxxx>
> 
> Reorganize I2C functions to accommodate SPI support
> Split the probe and factor out parts of the code
> that will be used in the SPI support
> 
> Signed-off-by: Lucas Tanure <tanureal@xxxxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Stefan Binding <sbinding@xxxxxxxxxxxxxxxxxxxxx>
> ---
>  drivers/platform/x86/bus-multi-instantiate.c | 150 ++++++++++++-------
>  1 file changed, 96 insertions(+), 54 deletions(-)
> 
> diff --git a/drivers/platform/x86/bus-multi-instantiate.c b/drivers/platform/x86/bus-multi-instantiate.c
> index 982dfecfd27c..50f1540762e9 100644
> --- a/drivers/platform/x86/bus-multi-instantiate.c
> +++ b/drivers/platform/x86/bus-multi-instantiate.c
> @@ -29,85 +29,129 @@ struct bmi_instance {
>  
>  struct bmi {
>  	int i2c_num;
> -	struct i2c_client *i2c_devs[];
> +	struct i2c_client **i2c_devs;
>  };
>  
> -static int bmi_probe(struct platform_device *pdev)
> +static int bmi_get_irq(struct platform_device *pdev, struct acpi_device *adev,
> +		       const struct bmi_instance *inst)
> +{
> +	int ret;
> +
> +	switch (inst->flags & IRQ_RESOURCE_TYPE) {
> +	case IRQ_RESOURCE_GPIO:
> +		ret = acpi_dev_gpio_irq_get(adev, inst->irq_idx);
> +		break;
> +	case IRQ_RESOURCE_APIC:
> +		ret = platform_get_irq(pdev, inst->irq_idx);
> +		break;
> +	default:
> +		ret = 0;
> +		break;
> +	}
> +
> +	if (ret < 0)
> +		dev_err_probe(&pdev->dev, ret, "Error requesting irq at index %d: %d\n",
> +			      inst->irq_idx, ret);
> +
> +	return ret;
> +}
> +
> +static void bmi_devs_unregister(struct bmi *bmi)
> +{
> +	while (bmi->i2c_num > 0)
> +		i2c_unregister_device(bmi->i2c_devs[--bmi->i2c_num]);
> +}
> +
> +/**
> + * bmi_i2c_probe - Instantiate multiple I2C devices from inst array
> + * @pdev:	Platform device
> + * @adev:	ACPI device
> + * @bmi:	Internal struct for Bus multi instantiate driver
> + * @inst:	Array of instances to probe
> + *
> + * Returns the number of I2C devices instantiate, Zero if none is found or a negative error code.
> + */
> +static int bmi_i2c_probe(struct platform_device *pdev, struct acpi_device *adev, struct bmi *bmi,
> +			 const struct bmi_instance *inst_array)
>  {
>  	struct i2c_board_info board_info = {};
> -	const struct bmi_instance *inst;
>  	struct device *dev = &pdev->dev;
> -	struct acpi_device *adev;
> -	struct bmi *bmi;
>  	char name[32];
> -	int i, ret;
> +	int i, ret = 0, count;
>  
> -	inst = device_get_match_data(dev);
> -	if (!inst) {
> -		dev_err(dev, "Error ACPI match data is missing\n");
> -		return -ENODEV;
> -	}
> -
> -	adev = ACPI_COMPANION(dev);
> -
> -	/* Count number of clients to instantiate */
>  	ret = i2c_acpi_client_count(adev);
> -	if (ret < 0)
> +	if (ret <= 0)
>  		return ret;

Please change this to:

		return ret == 0 ? -ENODEV : ret;

This helps making return value handler in the caller cleaner,
also see my upcoming review of patch 7/9.

> +	count = ret;
>  
> -	bmi = devm_kmalloc(dev, struct_size(bmi, i2c_devs, ret), GFP_KERNEL);
> -	if (!bmi)
> +	bmi->i2c_devs = devm_kcalloc(dev, count, sizeof(*bmi->i2c_devs), GFP_KERNEL);
> +	if (!bmi->i2c_devs)
>  		return -ENOMEM;
>  
> -	bmi->i2c_num = ret;
> -
> -	for (i = 0; i < bmi->i2c_num && inst[i].type; i++) {
> +	for (i = 0; i < count && inst_array[i].type; i++) {
>  		memset(&board_info, 0, sizeof(board_info));
> -		strlcpy(board_info.type, inst[i].type, I2C_NAME_SIZE);
> -		snprintf(name, sizeof(name), "%s-%s.%d", dev_name(dev), inst[i].type, i);
> +		strscpy(board_info.type, inst_array[i].type, I2C_NAME_SIZE);
> +		snprintf(name, sizeof(name), "%s-%s.%d", dev_name(dev), inst_array[i].type, i);
>  		board_info.dev_name = name;
> -		switch (inst[i].flags & IRQ_RESOURCE_TYPE) {
> -		case IRQ_RESOURCE_GPIO:
> -			ret = acpi_dev_gpio_irq_get(adev, inst[i].irq_idx);
> -			if (ret < 0) {
> -				dev_err(dev, "Error requesting irq at index %d: %d\n",
> -						inst[i].irq_idx, ret);
> -				goto error;
> -			}
> -			board_info.irq = ret;
> -			break;
> -		case IRQ_RESOURCE_APIC:
> -			ret = platform_get_irq(pdev, inst[i].irq_idx);
> -			if (ret < 0) {
> -				dev_dbg(dev, "Error requesting irq at index %d: %d\n",
> -					inst[i].irq_idx, ret);
> -				goto error;
> -			}
> -			board_info.irq = ret;
> -			break;
> -		default:
> -			board_info.irq = 0;
> -			break;
> -		}
> +
> +		ret = bmi_get_irq(pdev, adev, &inst_array[i]);
> +		if (ret < 0)
> +			goto error;
> +		board_info.irq = ret;
> +
>  		bmi->i2c_devs[i] = i2c_acpi_new_device(dev, i, &board_info);
>  		if (IS_ERR(bmi->i2c_devs[i])) {
>  			ret = dev_err_probe(dev, PTR_ERR(bmi->i2c_devs[i]),
>  					    "Error creating i2c-client, idx %d\n", i);
>  			goto error;
>  		}
> +		bmi->i2c_num++;
>  	}
> -	if (i < bmi->i2c_num) {
> +	if (bmi->i2c_num < count) {
>  		dev_err(dev, "Error finding driver, idx %d\n", i);
>  		ret = -ENODEV;
>  		goto error;
>  	}
>  
> -	platform_set_drvdata(pdev, bmi);
> -	return 0;
> +	dev_info(dev, "Instantiate %d I2C devices.\n", bmi->i2c_num);
>  
> +	return bmi->i2c_num;

And change this to return 0.

>  error:
> -	while (--i >= 0)
> -		i2c_unregister_device(bmi->i2c_devs[i]);
> +	dev_err_probe(dev, ret, "I2C error %d\n", ret);
> +	bmi_devs_unregister(bmi);
> +
> +	return ret;
> +}
> +
> +static int bmi_probe(struct platform_device *pdev)
> +{
> +	const struct bmi_instance *inst_array;
> +	struct device *dev = &pdev->dev;
> +	struct acpi_device *adev;
> +	struct bmi *bmi;
> +	int ret;
> +
> +	inst_array = device_get_match_data(dev);
> +	if (!inst_array) {
> +		dev_err(dev, "Error ACPI match data is missing\n");
> +		return -ENODEV;
> +	}
> +
> +	adev = ACPI_COMPANION(dev);
> +	if (!adev)
> +		return -ENODEV;
> +
> +	bmi = devm_kzalloc(dev, sizeof(*bmi), GFP_KERNEL);
> +	if (!bmi)
> +		return -ENOMEM;
> +
> +	platform_set_drvdata(pdev, bmi);
> +
> +	ret = bmi_i2c_probe(pdev, adev, bmi, inst_array);
> +	if (ret > 0)
> +		return 0;
> +	if (ret == 0)
> +		ret = -ENODEV;
>  
>  	return ret;

Then you can simplify the above to just:

	return bmi_i2c_probe(pdev, adev, bmi, inst_array);

:)

Regards,

Hans



>  }
> @@ -115,10 +159,8 @@ static int bmi_probe(struct platform_device *pdev)
>  static int bmi_remove(struct platform_device *pdev)
>  {
>  	struct bmi *bmi = platform_get_drvdata(pdev);
> -	int i;
>  
> -	for (i = 0; i < bmi->i2c_num; i++)
> -		i2c_unregister_device(bmi->i2c_devs[i]);
> +	bmi_devs_unregister(bmi);
>  
>  	return 0;
>  }
>