On Thu, Jun 7, 2018 at 11:28 PM, Simon Glass sjg@chromium.org wrote:
Hi Ramon,
On 3 June 2018 at 14:32, Ramon Fried ramon.fried@gmail.com wrote:
On Sat, Jun 2, 2018 at 10:19 PM, Ramon Fried ramon.fried@gmail.com wrote:
On Sat, Jun 2, 2018 at 9:03 PM, Heinrich Schuchardt xypron.glpk@gmx.de wrote:
On 06/02/2018 06:25 PM, Ramon Fried wrote:
Hi Simon, all.
I want to port a specific driver from Linux Kernel (Qualcomm smem) which is declared in Linux as platform device. The implementation is very specific and It doesn't fall into any defined uclass id. I still want to use the dm framework, what's the approach taken on these kind of things ? Is it possible to create a generic uclass id ?
Hello Ramon,
a major benefit of the driver model is that drivers are selected via the device tree.
In Linux the driver is in drivers/soc. Wouldn't it make sense to create a minimal uclass for platform devices in drivers/soc on U-Boot?
drivers/ram/ram-uclass.c shows what a minimal uclass looks like. The identifier has to be added in include/dm/uclass-id.h.
Best regards
Heinrich
Thanks for the comment Heinrich. My initial intention was to place the driver under drivers/soc and I do thing that creating a UCLASS_PLATFORM make sense, acutally, it's exaclt what I'm suggesting in a different name. The thing is that there's no apperent ops that I think will suit all the platform drivers as they're different in nature. So, I don't see any requirement to create a platform_uclass.c file.
Thanks, Ramon.
Added some initial contributors to uclass for comments.
It's OK to create a uclass if you need to. What does your driver do?
Hi Simon, thanks for replying. The driver purpose is to provide a way to access Qualcomm's shared memory region and to read and write properties to it accessed by other cores (Trustzone for instance). The Linux kernel driver I use as a reference (https://elixir.bootlin.com/linux/latest/source/drivers/soc/qcom/smem.c) relies heavily on device-tree bindings, and I wanted to keep as much of the driver intact.
As this is very specific to Qualcomm, I don't think that it fits any other UCLASS_ definition and thus I suggested adding UCLASS_PLATFORM which is intended for platform specific drivers/devices.
In such a case, the .ops will be empty as there isn't any shared functionailty that can be generalized.
Does this make sense ? should I ditch the driver-module idea and just implement it as piece of code under arch/arm/mach-snapdragon ?
Thanks, Ramon.
Regards, Simon