On 10/13/2011 02:34 AM, Grant Likely :

On Wed, Oct 12, 2011 at 06:57:12PM +0200, Nicolas Ferre wrote:

quoted

Add device tree probe support for atmel at_hdmac DMA driver.
Bindings are added to specify DMA controller configuration.

Signed-off-by: Nicolas Ferre <redacted>
---
 .../devicetree/bindings/dma/atmel-dma.txt          |   14 +++++++++
 drivers/dma/at_hdmac.c                             |   30 +++++++++++++++++++-
 2 files changed, 43 insertions(+), 1 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/dma/atmel-dma.txt

diff --git a/Documentation/devicetree/bindings/dma/atmel-dma.txt b/Documentation/devicetree/bindings/dma/atmel-dma.txt
new file mode 100644
index 0000000..3c046ee
--- /dev/null
+++ b/Documentation/devicetree/bindings/dma/atmel-dma.txt

@@ -0,0 +1,14 @@
+* Atmel Direct Memory Access Controller (DMA)
+
+Required properties:
+- compatible: Should be "atmel,<chip>-dma"
+- reg: Should contain DMA registers location and length
+- interrupts: Should contain DMA interrupt
+
+Examples:
+
+dma at ffffec00 {
+	compatible = "atmel,at91sam9g45-dma";
+	reg = <0xffffec00 0x200>;
+	interrupts = <21>;
+};

diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
index d1869c5..42bd64c 100644
--- a/drivers/dma/at_hdmac.c
+++ b/drivers/dma/at_hdmac.c

@@ -23,6 +23,8 @@
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
 
 #include "at_hdmac_regs.h"
 

@@ -1175,6 +1177,20 @@ static void atc_free_chan_resources(struct dma_chan *chan)
 
 /*--  Module Management  -----------------------------------------------*/
 
+#if defined(CONFIG_OF)
+static const struct of_device_id atmel_dma_dt_ids[] = {
+	{
+		.compatible = "atmel,at91sam9rl-dma",
+		.data = (void *)ATDMA_DEVTYPE_SAM9RL
+	}, {
+		.compatible = "atmel,at91sam9g45-dma",
+		.data = (void *)ATDMA_DEVTYPE_SAM9G45
+	}, { /* sentinel */ }
+};
+
+MODULE_DEVICE_TABLE(of, atmel_dma_dt_ids);
+#endif
+
 static struct platform_device_id atdma_devtypes[] = {
 	{
 		.name = "at91sam9rl_dma",

@@ -1187,6 +1203,17 @@ static struct platform_device_id atdma_devtypes[] = {
 	}
 };
 
+static inline enum atdma_devtype __init at_dma_get_driver_data(
+					struct platform_device *pdev)
+{
+	if (pdev->dev.of_node) {
+		const struct of_device_id *match;
+		match = of_match_node(atmel_dma_dt_ids, pdev->dev.of_node);

You'll need to check the return value.  It is possible (though
unlikely) to have a device with an of_node but still happens to get
bound via the platform_driver id_table.  In which case match would be
NULL here.

Ok, I add:

                if (match == NULL)
                        return ATDMA_DEVTYPE_UNDEFINED;

Which will take care about this case.

Otherwise, you can add my a-b after fixing that bug.

Acked-by: Grant Likely <redacted>

Thanks a lot for your reviews Grant,

Bye,
-- 
Nicolas Ferre