Re: [PATCH v6 3/9] spi: Support selection of the index of the ACPI Spi Resource before alloc

[Hans de Goede <hdegoede@xxxxxxxxxx>]

Hi,

On 1/21/22 18:24, Stefan Binding wrote:
> If a node contains more than one Spi Resources, it may be necessary to
> use an index to select which one you want to allocate a spi device for.
> 
> Signed-off-by: Stefan Binding <sbinding@xxxxxxxxxxxxxxxxxxxxx>

Thanks, patch looks good to me:

Reviewed-by: Hans de Goede <hdegoede@xxxxxxxxxx>

Regards,

Hans


> ---
>  drivers/spi/spi.c       | 51 +++++++++++++++++++++++++++++++++++------
>  include/linux/spi/spi.h |  3 ++-
>  2 files changed, 46 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
> index 13f4701f0694..06c0a308b38b 100644
> --- a/drivers/spi/spi.c
> +++ b/drivers/spi/spi.c
> @@ -2320,6 +2320,8 @@ struct acpi_spi_lookup {
>  	int			irq;
>  	u8			bits_per_word;
>  	u8			chip_select;
> +	int			n;
> +	int			index;
>  };
>  
>  static void acpi_spi_parse_apple_properties(struct acpi_device *dev,
> @@ -2351,6 +2353,8 @@ static void acpi_spi_parse_apple_properties(struct acpi_device *dev,
>  		lookup->mode |= SPI_CPHA;
>  }
>  
> +static struct spi_controller *acpi_spi_find_controller_by_adev(struct acpi_device *adev);
> +
>  static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
>  {
>  	struct acpi_spi_lookup *lookup = data;
> @@ -2364,14 +2368,35 @@ static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
>  		sb = &ares->data.spi_serial_bus;
>  		if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
>  
> +			if (lookup->index != -1 && lookup->n++ != lookup->index)
> +				return 1;
> +
> +			if (lookup->index == -1 && !ctlr)
> +				return -ENODEV;
> +
>  			status = acpi_get_handle(NULL,
>  						 sb->resource_source.string_ptr,
>  						 &parent_handle);
>  
> -			if (ACPI_FAILURE(status) ||
> -			    ACPI_HANDLE(ctlr->dev.parent) != parent_handle)
> +			if (ACPI_FAILURE(status))
>  				return -ENODEV;
>  
> +			if (ctlr) {
> +				if (ACPI_HANDLE(ctlr->dev.parent) != parent_handle)
> +					return -ENODEV;
> +			} else {
> +				struct acpi_device *adev;
> +
> +				if (acpi_bus_get_device(parent_handle, &adev))
> +					return -ENODEV;
> +
> +				ctlr = acpi_spi_find_controller_by_adev(adev);
> +				if (!ctlr)
> +					return -ENODEV;
> +
> +				lookup->ctlr = ctlr;
> +			}
> +
>  			/*
>  			 * ACPI DeviceSelection numbering is handled by the
>  			 * host controller driver in Windows and can vary
> @@ -2414,14 +2439,21 @@ static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
>   * acpi_spi_device_alloc - Allocate a spi device, and fill it in with ACPI information
>   * @ctlr: controller to which the spi device belongs
>   * @adev: ACPI Device for the spi device
> + * @index: Index of the spi resource inside the ACPI Node
>   *
>   * This should be used to allocate a new spi device from and ACPI Node.
>   * The caller is responsible for calling spi_add_device to register the spi device.
>   *
> + * If ctlr is set to NULL, the Controller for the spi device will be looked up
> + * using the resource.
> + * If index is set to -1, index is not used.
> + * Note: If index is -1, ctlr must be set.
> + *
>   * Return: a pointer to the new device, or ERR_PTR on error.
>   */
>  struct spi_device *acpi_spi_device_alloc(struct spi_controller *ctlr,
> -					 struct acpi_device *adev)
> +					 struct acpi_device *adev,
> +					 int index)
>  {
>  	acpi_handle parent_handle = NULL;
>  	struct list_head resource_list;
> @@ -2429,8 +2461,13 @@ struct spi_device *acpi_spi_device_alloc(struct spi_controller *ctlr,
>  	struct spi_device *spi;
>  	int ret;
>  
> +	if (!ctlr && index == -1)
> +		return ERR_PTR(-EINVAL);
> +
>  	lookup.ctlr		= ctlr;
>  	lookup.irq		= -1;
> +	lookup.index		= index;
> +	lookup.n		= 0;
>  
>  	INIT_LIST_HEAD(&resource_list);
>  	ret = acpi_dev_get_resources(adev, &resource_list,
> @@ -2443,7 +2480,7 @@ struct spi_device *acpi_spi_device_alloc(struct spi_controller *ctlr,
>  
>  	if (!lookup.max_speed_hz &&
>  	    ACPI_SUCCESS(acpi_get_parent(adev->handle, &parent_handle)) &&
> -	    ACPI_HANDLE(ctlr->dev.parent) == parent_handle) {
> +	    ACPI_HANDLE(lookup.ctlr->dev.parent) == parent_handle) {
>  		/* Apple does not use _CRS but nested devices for SPI slaves */
>  		acpi_spi_parse_apple_properties(adev, &lookup);
>  	}
> @@ -2451,9 +2488,9 @@ struct spi_device *acpi_spi_device_alloc(struct spi_controller *ctlr,
>  	if (!lookup.max_speed_hz)
>  		return ERR_PTR(-ENODEV);
>  
> -	spi = spi_alloc_device(ctlr);
> +	spi = spi_alloc_device(lookup.ctlr);
>  	if (!spi) {
> -		dev_err(&ctlr->dev, "failed to allocate SPI device for %s\n",
> +		dev_err(&lookup.ctlr->dev, "failed to allocate SPI device for %s\n",
>  			dev_name(&adev->dev));
>  		return ERR_PTR(-ENOMEM);
>  	}
> @@ -2478,7 +2515,7 @@ static acpi_status acpi_register_spi_device(struct spi_controller *ctlr,
>  	    acpi_device_enumerated(adev))
>  		return AE_OK;
>  
> -	spi = acpi_spi_device_alloc(ctlr, adev);
> +	spi = acpi_spi_device_alloc(ctlr, adev, -1);
>  	if (IS_ERR(spi)) {
>  		if (PTR_ERR(spi) == -ENOMEM)
>  			return AE_NO_MEMORY;
> diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
> index d159cef12f1a..e5bbb9cbd3d7 100644
> --- a/include/linux/spi/spi.h
> +++ b/include/linux/spi/spi.h
> @@ -762,7 +762,8 @@ extern void spi_unregister_controller(struct spi_controller *ctlr);
>  
>  #if IS_ENABLED(CONFIG_ACPI)
>  extern struct spi_device *acpi_spi_device_alloc(struct spi_controller *ctlr,
> -						struct acpi_device *adev);
> +						struct acpi_device *adev,
> +						int index);
>  #endif
>  
>  /*
>