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NNTP-Posting-Date: Sat, 21 Feb 2015 02:15:46 -0600
From: Gareth Owen <gwowen@gmail.com>
Newsgroups: comp.os.linux.development.system
Subject: Module loading with multiple devices...
Date: Sat, 21 Feb 2015 08:15:45 +0000
Message-ID: <87mw47wuha.fsf@gmail.com>
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I've written a device driver for an FPGA peripheral (with DMA channels
to/from the processing) that works well, with the device enumerated in
the device-tree.  What I need to to is create multiple instances of that
device, and have the driver manage them.

The original driver creates 

/dev/mydev0

with device_create(), and then manipulated from userspace with ioctl()s.

My question is, if I have multiple instances of the device in the device
tree, how does the kernel load the driver, and how do I need to manage
the creation of the device class and any references counts to that device
class at driver load/unload time.

Is the probe() function run once per device, or just once at module
load?  Is the idea then to have the class pointer a static variable in
the module (i.e. just one shared between all instances) and keep all
instance variables (IRQ, dma channels) in the dynamically allocated
structures?