From: arnd@arndb•de (Arnd Bergmann)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH V6 2/2] dmaengine: add helper function to request a slave DMA channel
Date: Mon, 17 Sep 2012 11:59:27 +0000 [thread overview]
Message-ID: <201209171159.27359.arnd@arndb.de> (raw)
In-Reply-To: <1347852805.1943.130.camel@vkoul-udesk3>
On Monday 17 September 2012, Vinod Koul wrote:
> On Fri, 2012-09-14 at 17:41 -0500, Jon Hunter wrote:
> > +/**
> > + * dma_request_slave_channel - try to allocate an exclusive slave
> > channel
> > + * @dev: pointer to client device structure
> > + * @name: slave channel name
> > + */
> > +struct dma_chan *dma_request_slave_channel(struct device *dev, char *name)
> > +{
> > + /* If device-tree is present get slave info from here */
> > + if (dev->of_node)
> > + return of_dma_request_slave_channel(dev->of_node, name);
> > +
> Shouldn't this be conditionally compiled only when OF is built. I think
> this might be problematic for systems which doesn't have device tree.
> Or perhaps you can declare these symbols as dummy in of_dma.h when
> device tree is not selected.
Right, good point. I'd prefer the dummy functions, since that is in line
with what a lot of other subsystems do:
#ifdef CONFIG_OF
extern int of_dma_controller_register(struct device_node *np,
struct dma_chan *(*of_dma_xlate)
(struct of_phandle_args *, struct of_dma *),
void *data);
extern void of_dma_controller_free(struct device_node *np);
extern struct dma_chan *of_dma_request_slave_channel(struct device_node *np,
char *name);
extern struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec,
struct of_dma *ofdma);
#else
static inline int of_dma_controller_register(struct device_node *np,
struct dma_chan *(*of_dma_xlate)
(struct of_phandle_args *, struct of_dma *),
void *data)
{
return -ENODEV;
}
static inline void of_dma_controller_free(struct device_node *np)
{
}
static inline struct dma_chan *of_dma_request_slave_channel(struct device_node *np,
char *name)
{
return NULL;
}
static inline struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec,
struct of_dma *ofdma)
{
return NULL;
}
#endif
I believe that Jon is on vacation this week, so if this is the only issue
holding up the merge, maybe you can change this in his patch directly, or
I can send an updated version if you prefer.
Arnd
next prev parent reply other threads:[~2012-09-17 11:59 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-14 22:41 [PATCH V6 0/2] of: Add generic device tree DMA helpers Jon Hunter
2012-09-14 22:41 ` [PATCH V6 1/2] " Jon Hunter
2012-09-14 22:46 ` Stephen Warren
2012-09-15 0:14 ` Russell King - ARM Linux
2012-09-17 20:42 ` Arnd Bergmann
2012-09-17 23:06 ` David Brown
2012-09-18 12:50 ` Arnd Bergmann
2012-09-18 22:19 ` Mitch Bradley
2012-09-18 22:32 ` Russell King - ARM Linux
2012-09-19 11:09 ` Arnd Bergmann
2012-09-19 14:40 ` Mitch Bradley
2012-09-19 13:52 ` Matt Porter
2012-09-19 14:07 ` Matt Porter
2012-09-19 14:24 ` Arnd Bergmann
2012-09-19 14:36 ` Rob Herring
2012-09-19 14:40 ` Matt Porter
2012-09-19 14:50 ` Arnd Bergmann
2012-09-19 21:25 ` Mitch Bradley
2012-09-19 14:10 ` Rob Herring
2012-09-14 22:41 ` [PATCH V6 2/2] dmaengine: add helper function to request a slave DMA channel Jon Hunter
2012-09-17 3:33 ` Vinod Koul
2012-09-17 11:59 ` Arnd Bergmann [this message]
2012-09-17 22:36 ` Russell King - ARM Linux
2012-09-18 3:13 ` Vinod Koul
2012-09-18 13:21 ` Matt Porter
2012-09-18 15:20 ` Arnd Bergmann
2012-09-18 18:10 ` Russell King - ARM Linux
2012-09-24 22:25 ` Jon Hunter
2012-09-25 4:35 ` Vinod Koul
2012-10-16 2:43 ` Shawn Guo
2012-10-16 2:39 ` Vinod Koul
2012-11-09 20:01 ` Jon Hunter
2012-11-16 1:37 ` Vinod Koul
2012-11-16 8:39 ` Nicolas Ferre
2012-11-16 15:45 ` Jon Hunter
2012-11-28 17:06 ` Vinod Koul
2012-12-19 17:12 ` Jon Hunter
2012-12-20 14:57 ` Vinod Koul
2012-09-18 3:00 ` Vinod Koul
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