linux-kernel - Re: [V2] mtd: devices: docg3:- Handle return value of devm

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Message-ID: <8760mp151h.fsf@belgarion.home>
Date:   Mon, 12 Dec 2016 17:32:58 +0100
From:   Robert Jarzmik <robert.jarzmik@...e.fr>
To:     arvind Yadav <arvind.yadav.cs@...il.com>
Cc:     Boris Brezillon <boris.brezillon@...e-electrons.com>,
        dwmw2@...radead.org, computersforpeace@...il.com,
        marek.vasut@...il.com, richard@....at, cyrille.pitchen@...el.com,
        linux-mtd@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [V2] mtd: devices: docg3:- Handle return value of devm_ioremap.

arvind Yadav <arvind.yadav.cs@...il.com> writes:

> There is problem, if you will use devm_ioremap_resource instead of devm_ioremap,
> than devm_ioremap_resource will call request_mem_region().
> request_mem_region() allows to tell the kernel that this driver is going to use
> this range of I/O addresses, which will prevent other drivers to make an
> overlapping call to request_mem_region If other driver want to use same address
> space to access then it will not allow. Means we can not share same address
> space
> between two driver.

Hi,

You're right Arvind, and still, it's worth noticing that the docg3 access
semantics imply a "reserved" resource path (see how doc_register_readb() does a
write and how this cannot be shared with another driver).

Therefore I'll be willing to ack a mix of your both patches, the
devm_ioremap_resource() from Boris and the error message from your patch.

Cheers.

--
Robert