Den 28.05.2015 23:17, skrev Stephen Warren:
On 05/13/2015 01:00 PM, Eric Anholt wrote:
This gives us a function for making mailbox property channel requests
of the firmware, which is most notable in that it will let us get and
set clock rates.
...
Note that I don't think I've done what srwarren wanted for
-EPROBE_DEFER, because I'm not clear what he wants. I think he might
just be asking for a function that does:
/*
* Returns 0 if the firmware device is probed and available, otherwise
* -EPROBE_DEFER.
*/
int rpi_firmware_get(struct device_node *firmware_node)
{
struct platform_device *pdev = of_find_device_by_node(of_node);
if (!platform_get_drvdata(pdev))
of_find_device_by_node() can return NULL if the device can't be found.
platform_get_drvdata() can't handle a NULL pointer.
return -EPROBE_DEFER;
return 0;
}
EXPORT_SYMBOL(rpi_firmware_get)
If that's all, I'm happy to add it.
Yes, there definitely needs to be something that clients can call at
probe() time to make sure the firmware driver is there already. That
check is quite different from actually sending a request to the FW, so
I'd certainly expect a separate function for that.
A try_module_get() here would make sure this module won't go away while a
client relies on it. For that we would need a rpi_firmware_put() as well.
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