On 08/11/2011 06:07 PM, Robin Holt wrote: > 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. nitpicking follows inline: > Signed-off-by: Robin Holt > To: Kumar Gala > To: Wolfgang Grandegger , > To: Marc Kleine-Budde , > To: U Bhaskar-B22300 > To: Scott Wood > To: Grant Likely > Cc: socketcan-core-0fE9KPoRgkgATYTw5x5z8w@public.gmane.org, > Cc: netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, > Cc: PPC list > Cc: devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org > --- > .../devicetree/bindings/net/can/fsl-flexcan.txt | 2 + > drivers/net/can/flexcan.c | 33 +++++++++++++++----- > 2 files changed, 27 insertions(+), 8 deletions(-) > > diff --git a/Documentation/devicetree/bindings/net/can/fsl-flexcan.txt b/Documentation/devicetree/bindings/net/can/fsl-flexcan.txt > index c78dcbb..a4382c7 100644 > --- a/Documentation/devicetree/bindings/net/can/fsl-flexcan.txt > +++ b/Documentation/devicetree/bindings/net/can/fsl-flexcan.txt > @@ -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 = <0x0bebc1fc>; Does the device tree support dec coded integers? IMHO a frequency is best expressed in decimal. > }; > diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c > index 662f832..d40c38e 100644 > --- a/drivers/net/can/flexcan.c > +++ b/drivers/net/can/flexcan.c > @@ -33,6 +33,7 @@ > #include > #include > #include > +#include > #include > > #define DRV_NAME "flexcan" > @@ -929,12 +930,26 @@ static int __devinit flexcan_probe(struct platform_device *pdev) > 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; > + > + clk = NULL; Hmmm - what about moving the clk = NULL into the definition of clk? > + 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 +982,7 @@ 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 +1017,8 @@ 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 +1036,8 @@ 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); > Marc -- Pengutronix e.K. | Marc Kleine-Budde | Industrial Linux Solutions | Phone: +49-231-2826-924 | Vertretung West/Dortmund | Fax: +49-5121-206917-5555 | Amtsgericht Hildesheim, HRA 2686 | http://www.pengutronix.de |