[PATCH v4 3/3] can: c_can: Add runtime PM support to Bosch C_CAN/D_CAN controller

[Hiremath, Vaibhav]

On Sat, Aug 04, 2012 at 00:39:25, Marc Kleine-Budde wrote:
> On 08/03/2012 08:32 AM, Hiremath, Vaibhav wrote:
> > On Thu, Aug 02, 2012 at 18:43:11, AnilKumar, Chimata wrote:
> >> Add Runtime PM support to C_CAN/D_CAN controller. The runtime PM
> >> APIs control clocks for C_CAN/D_CAN IP and prevent access to the
> >> register of C_CAN/D_CAN IP when clock is turned off.
> >>
> >> Signed-off-by: AnilKumar Ch <anilkumar at ti.com>
> >> ---
> >>  drivers/net/can/c_can/c_can_platform.c |    8 ++++++++
> >>  1 file changed, 8 insertions(+)
> >>
> >> diff --git a/drivers/net/can/c_can/c_can_platform.c b/drivers/net/can/c_can/c_can_platform.c
> >> index d0a66cf..83a1e17 100644
> >> --- a/drivers/net/can/c_can/c_can_platform.c
> >> +++ b/drivers/net/can/c_can/c_can_platform.c
> >> @@ -32,6 +32,7 @@
> >>  #include <linux/clk.h>
> >>  #include <linux/of.h>
> >>  #include <linux/of_device.h>
> >> +#include <linux/pm_runtime.h>
> >>  
> >>  #include <linux/can/dev.h>
> >>  
> >> @@ -177,6 +178,9 @@ static int __devinit c_can_plat_probe(struct platform_device *pdev)
> >>  		goto exit_free_device;
> >>  	}
> >>  
> >> +	pm_runtime_enable(&pdev->dev);
> >> +	pm_runtime_get_sync(&pdev->dev);
> >> +
> > 
> > If module is inserted or built into the kernel, module stays in enabled 
> > state always, isn't that wrong?
> > Ideally, you should enable the module when it is required or being used.
> 
> Good point.
> 
> If you don't access the module's registers in the probe- (or its
> subroutines) it should be enough to enable the module in the open()
> function. Have a look at clk_prepare_enable / clk_disable_unprepare in
> the flexcan driver.
> 

Yeah Marc, something similar, above runtime pm api's should be moved to 
open-n-close.

Thanks,
Vaibhav

> Marc
> 
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