Messages in this thread | | | From | "Voss, Nikolaus" <> | Date | Wed, 9 Nov 2011 17:01:07 +0100 | Subject | RE: [PATCH V3 2/4] drivers/i2c/busses/i2c-at91.c: add new driver |
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Hi Ryan,
> > +#include <mach/at91_twi.h> > > > This include file looks like it only contains register definitions which > are used in this file. Would be good to either move them directly into > this driver or move the header file to this directory and make it a > local include.
Ok.
> > + > > + dev->dev = get_device(&pdev->dev); > > > Is this (and the put_device(&pdev->dev) in the exit code) necessary? I > see that some other i2c drivers do this also, but I'm not familiar with > using it in other device drivers. Isn't the reference count for > pdev->dev already incremented by the fact we are probing the device?
It is incremented by the platform_device_register() which does a device_add(). This seems to be enough, I removed the get-/put_device().
> > > + dev->irq = irq->start; > > + platform_set_drvdata(pdev, dev); > > + > > + dev->clk = clk_get(&pdev->dev, "twi_clk"); > > > This didn't get answered. Can't you just do: > > dev->clk = clk_get(&pdev->dev, NULL); > > and clkdev should figure out the correct clock based on the device pointer?
No, this doesn't work on at91 since the clocks have no dev_id property but only con_id. I cannot see a reason for this, but that's the way it's done. Multiple hardware interfaces are handled via a lookup table.
> > + rc = i2c_del_adapter(&dev->adapter); > > > Most of the other i2c drivers don't check the return code for > i2c_del_adapter. If this fails then you will unload the module, but > potentially leak resources that i2c_del_adapter failed to free up. Not > sure what the correct answer is here.
I don't really check the value but use it has exit code for the remove()- function to indicate something went wrong. Just ignoring it wouldn't heal the resource leakage.
Thanks for reviewing,
Niko
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