[PATCH] can: flexcan: add 2nd clock to support imx53 and newer

[Lothar Waßmann]

Hi,

Marc Kleine-Budde writes:
> On 07/18/2012 04:12 AM, Hui Wang wrote:
> > Marc Kleine-Budde wrote:
> >> From: Steffen Trumtrar <s.trumtrar at pengutronix.de>
> >>
> >> This patch add support for a second clock to the flexcan driver. On
> >> modern
> >> freescale ARM cores like the imx53 and imx6q two clocks ("ipg" and "per")
> >> must be enabled in order to access the CAN core.
> >> -        clock_freq = clk_get_rate(clk);
> >>      }
> >>  
> >>      mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> >> @@ -1039,7 +1052,8 @@ static int __devinit flexcan_probe(struct
> >> platform_device *pdev)
> >>          CAN_CTRLMODE_BERR_REPORTING;
> >>      priv->base = base;
> >>      priv->dev = dev;
> >> -    priv->clk = clk;
> >> +    priv->clk_ipg = clk_ipg;
> >> +    priv->clk_per = clk_per;
> >>      priv->pdata = pdev->dev.platform_data;
> >>      priv->devtype_data = devtype_data;
> >>  
> >> @@ -1067,9 +1081,11 @@ static int __devinit flexcan_probe(struct
> >> platform_device *pdev)
> >>   failed_map:
> >>      release_mem_region(mem->start, mem_size);
> >>   failed_get:
> >> -    if (clk)
> >> -        clk_put(clk);
> >>   failed_clock:
> >> +    if (clk_per)
> >>   
> > Use if (!IS_ERR(clk_per))
> 
> Yes, good catch.
> 
> Is it allowed to call clk_put with a NULL pointer? Both clocks can be
> NULL, if the frequency is defined via the device tree, this is case for
> powerpc.
> 
This has been discussed here already several times. Everything
returned by clk_get() that does not satisfy the IS_ERR() check, is a
valid clk cookie and can be used for the clk API calls.


Lothar Waßmann
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