On 2012年07月06日 13:52, Mika Westerberg wrote:
On Thu, Jul 05, 2012 at 03:01:57PM +0800, Zhang Rui wrote:
+Note that although these are ACPI devices, we prefer to use PnP drivers
for them,
+this is because:
+1. all the non-ACPI-predefined Devices are exported as PnP devices as
well
+2. PnP bus is a well designed bus. Probing via PnP layer saves a lot of
work
+ for the device driver, e.g. getting& parsing ACPI resources.
(Nice BKM, thanks for sharing)
I have few questions about using PnP drivers instead of pure ACPI drivers.
ACPI 5.0 defined some new resources, for example "Fixed DMA descriptor"
that has information about the request line + channel for the device to
use. Hovewer, PnP drivers pass resources as 'struct resource', which
basically only has start and end - how do you represent all this new stuff
using 'struct resource'?
I think we can add new interface to get acpi specific resources. e.g
struct acpi_resource pnp_get_acpi_resource(...). When the pnp acpi devices
were initialized, put those acpi specific resources into a new resource list
pnpdev->acpi_resources. What pnp_get_acpi_resource does is to get specified
type acpi resources and return. We also need to define some acpi resource types.
ACPI_RESOURCE_DMA
ACPI_RESOURCE_I2C_SERIALBUS
ACPI_RESOURCE_SPI_SERIALBUS
ACPI_RESOURCE_UART_SERIALBUS
ACPI_RESOURCE_COMMON_SERIALBUS
...
How about this? welcome to comments.
Or should we use acpi_walk_resources() where 'struct resource' is not
suitable?
--
Best Regards
Tianyu Lan
linux kernel enabling team
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