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flexcan: Prefer device tree clock frequency if available.

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If our CAN device's device tree node has a clock-frequency property,
then use that value for the can devices clock frequency.  If not, fall
back to asking the platform/mach code for the clock frequency associated
with the flexcan device.

Signed-off-by: Robin Holt <holt@sgi.com>
Acked-by: Wolfgang Grandegger <wg@grandegger.com>,
Cc: Kumar Gala <galak@kernel.crashing.org>
Cc: Marc Kleine-Budde <mkl@pengutronix.de>,
Cc: U Bhaskar-B22300 <B22300@freescale.com>
Cc: Scott Wood <scottwood@freescale.com>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: socketcan-core@lists.berlios.de,
Cc: netdev@vger.kernel.org,
Cc: PPC list <linuxppc-dev@lists.ozlabs.org>
Cc: devicetree-discuss@lists.ozlabs.org
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
holt@sgi.com 2011-08-16 17:32:23 +00:00 committed by David S. Miller
parent c8aef4cb78
commit 97efe9aef1
2 changed files with 27 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
Documentation/devicetree/bindings/net/can/fsl-flexcan.txt
View File

@ -11,6 +11,7 @@ Required properties:
- reg : Offset and length of the register set for this device
- interrupts : Interrupt tuple for this device
- clock-frequency : The oscillator frequency driving the flexcan device
Example:
@ -19,4 +20,5 @@ Example:
reg = <0x1c000 0x1000>;
interrupts = <48 0x2>;
interrupt-parent = <&mpic>;
clock-frequency = <200000000>; // filled in by bootloader
};

34
drivers/net/can/flexcan.c
View File

@ -33,6 +33,7 @@
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#define DRV_NAME "flexcan"
@ -925,16 +926,29 @@ static int __devinit flexcan_probe(struct platform_device *pdev)
struct net_device *dev;
struct flexcan_priv *priv;
struct resource *mem;
struct clk *clk;
struct clk *clk = NULL;
void __iomem *base;
resource_size_t mem_size;
int err, irq;
u32 clock_freq = 0;
clk = clk_get(&pdev->dev, NULL);
if (IS_ERR(clk)) {
dev_err(&pdev->dev, "no clock defined\n");
err = PTR_ERR(clk);
goto failed_clock;
if (pdev->dev.of_node) {
const u32 *clock_freq_p;
clock_freq_p = of_get_property(pdev->dev.of_node,
"clock-frequency", NULL);
if (clock_freq_p)
clock_freq = *clock_freq_p;
}
if (!clock_freq) {
clk = clk_get(&pdev->dev, NULL);
if (IS_ERR(clk)) {
dev_err(&pdev->dev, "no clock defined\n");
err = PTR_ERR(clk);
goto failed_clock;
}
clock_freq = clk_get_rate(clk);
}
mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
@ -967,7 +981,7 @@ static int __devinit flexcan_probe(struct platform_device *pdev)
dev->flags |= IFF_ECHO; /* we support local echo in hardware */
priv = netdev_priv(dev);
priv->can.clock.freq = clk_get_rate(clk);
priv->can.clock.freq = clock_freq;
priv->can.bittiming_const = &flexcan_bittiming_const;
priv->can.do_set_mode = flexcan_set_mode;
priv->can.do_get_berr_counter = flexcan_get_berr_counter;
@ -1002,7 +1016,8 @@ static int __devinit flexcan_probe(struct platform_device *pdev)
failed_map:
release_mem_region(mem->start, mem_size);
failed_get:
clk_put(clk);
if (clk)
clk_put(clk);
failed_clock:
return err;
}
@ -1020,7 +1035,8 @@ static int __devexit flexcan_remove(struct platform_device *pdev)
mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
release_mem_region(mem->start, resource_size(mem));
clk_put(priv->clk);
if (priv->clk)
clk_put(priv->clk);
free_candev(dev);