Re: [PATCH 2/5] dmaengine: Add STM32 DMAMUX driver
From: Pierre Yves MORDRET
Date: Thu May 04 2017 - 11:29:04 EST
On 05/01/2017 08:03 AM, Vinod Koul wrote:
> On Wed, Apr 26, 2017 at 09:17:37AM +0000, Pierre Yves MORDRET wrote:
>>>> + ret = of_property_read_u32(node, "dma-channels",
>>>> + &dmamux->dmamux_channels);
>>> can we have property_xxx calls alone, that way driver is not strictly
>>> dependent on of
>> Can you please explain what you are asking for ? Not sure to understand
> Use device_property_read_u32() which is a generic property API.
OK Will be done in V2
>>>> +static int __init stm32_dmamux_init(void)
>>>> + return platform_driver_register(&stm32_dmamux_driver);
>>> why not module init, wouldnt defer probe solve the dependencies
>> The reason behind many devices (device_initcall level) rely on DMAs. If
>> init is deferred DMAMUX driver will be probed twice if dependents rely
>> on it. This sounds not a good call. This explains arch_initcall level.
> Why not deferred probe was introduced to help with dependencies...
Most DMAs devices are already in subsys_initcall to avoid multiple
useless probe when clients are deferred. This DMAMUx is itself on top of
DMAMUX ---> DMA#1 ---> Device Client #1
| |--> Device Client #2
| |--> Device Client #N
|--> DMA#N ---> Device Client #1
|--> Device Client #2
|--> Device Client #N
arch_initcall might a good call in this case for DMAMUX.