From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: David Daney <ddaney.cavm@gmail.com>
Cc: David Daney <ddaney@caviumnetworks.com>,
        Tomasz Nowicki <tomasz.nowicki@linaro.org>,
        linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org,
        Len Brown <lenb@kernel.org>, Robert Richter <rrichter@cavium.com>,
        David Daney <david.daney@cavium.com>
Subject: Re: [PATCH] acpi, property: Export acpi_dev_prop_read_single call.
Date: Thu, 06 Aug 2015 01:23:06 +0200
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On Wednesday, August 05, 2015 01:14:49 PM David Daney wrote:
> On 08/05/2015 10:26 AM, David Daney wrote:
> > On 08/05/2015 06:43 AM, Tomasz Nowicki wrote:
> >> On 05.08.2015 15:48, Rafael J. Wysocki wrote:
> >>> On Tuesday, August 04, 2015 04:01:59 PM David Daney wrote:
> >>>> From: Tomasz Nowicki <tomasz.nowicki@linaro.org>
> >>>>
> >>>> Fixes the following build error when building drivers as modules:
> >>>>
> >>>>   ERROR: "acpi_dev_prop_read_single" [drivers/net/phy/mdio-octeon.ko]
> >>>> undefined!
> >>>>   ERROR: "acpi_dev_prop_read_single"
> >>>> [drivers/net/ethernet/cavium/thunder/thunder_bgx.ko] undefined!
> >>>
> >>> Can you please tell me why the drivers in question use that function
> >>> directly, although they aren't supposed to?
> >>>
> >>> Clearly, their authors had not tried to build them as modules or they
> >>> would have noticed the problem at the development stage already.
> >>>
> >>> What would be wrong with using the generic device properties API
> >>> instead?
> >>>
> >> Yes, you are right. We should use:
> >> int device_property_read_u64_array(struct device *dev, const char
> >> *propname, u64 *val, size_t nval);
> >>
> >
> > Thanks all, for the review and suggestions.  We we try the suggested
> > approach and see how it goes...
> >
> 
> Actually I don't think device_property_read_u64_array() will work.
> 
> We are traversing a reference to a different acpi_device via 
> acpi_dev_get_property_reference(),

Why?

> so there is no struct device * 
> available for a call to device_property_read_u64_array().  This looks 
> like a deficiency in the device_property_* framework, so for the time 
> being I guess we will call acpi_dev_get_property(), which is exported, 
> and decode the thing in the driver.

Please don't.

I'd like to understand what's missing.

Thanks,
Rafael

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