How does the driver initialize corresponding with several same devices ?
I make a driver module and built in the kernel. There are three devices use the same driver on the hardware platform. To use each device, the probe function of the driver module should be probed. So, the driver module is registered in the kernel. My question is, how times should the probe function of the driver be called and create nodes in devfs to corresponding with the three devices?
On Wed, Apr 18, 2012 at 05:16:01PM +0800, Li Haifeng wrote:
I make a driver module and built in the kernel. There are three devices use the same driver on the hardware platform. To use each device, the probe function of the driver module should be probed. So, the driver module is registered in the kernel.
My question is, how times should the probe function of the driver be called and create nodes in devfs to corresponding with the three devices?
It depends on what your architecture supports. If you have support for device tree, your entry in the device tree will make the subsystem call your probe function for each device it finds. You can then check the `compatible` entry of the device node and your driver is then able to register itself to the kernel subsystem. Greetings, Philipp
On Wed, Apr 18, 2012 at 11:16 AM, Li Haifeng <omycle@gmail.com> wrote:
I make a driver module and built in the kernel. There are three devices use the same driver on the hardware platform. To use each device, the probe function of the driver module should be probed. So, the driver module is registered in the kernel.
My question is, how times should the probe function of the driver be called and create nodes in devfs to corresponding with the three devices?
Your driver probe function has to be called only once. You should have in your driver a software representation of each device and register each one with the corresponding subsystem and with the kernel kernel device model to populate /dev with your device nodes. How do you represent your devices internally is up to you, it can be assigned on your module init function as a static array or you can do it dynamically using a linked list. Look at any driver inside drivers/char for reference. Hope it helps, -- Javier Martínez Canillas (+34) 682 39 81 69 Barcelona, Spain
On Wed, Apr 18, 2012 at 12:59 PM, Javier Martinez Canillas <martinez.javier@gmail.com> wrote:
On Wed, Apr 18, 2012 at 11:16 AM, Li Haifeng <omycle@gmail.com> wrote:
I make a driver module and built in the kernel. There are three devices use the same driver on the hardware platform. To use each device, the probe function of the driver module should be probed. So, the driver module is registered in the kernel.
My question is, how times should the probe function of the driver be called and create nodes in devfs to corresponding with the three devices?
Your driver probe function has to be called only once. You should have in your driver a software representation of each device and register each one with the corresponding subsystem and with the kernel kernel device model to populate /dev with your device nodes.
How do you represent your devices internally is up to you, it can be assigned on your module init function as a static array or you can do it dynamically using a linked list.
Look at any driver inside drivers/char for reference.
Sorry, didn't understand your question. Forget about my answer and sorry for the noise :) Regards, -- Javier Martínez Canillas (+34) 682 39 81 69 Barcelona, Spain
participants (3)
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Javier Martinez Canillas -
Li Haifeng -
Philipp Ittershagen