Re: [PATCH 1/9] Staging/iio/adc/touchscreen/MXS: add proper clock handling

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Hi Lothar,

On Monday 23 September 2013 17:30:18 Lothar Waßmann wrote:
> > [...]
> > @@ -928,6 +931,9 @@ static int mxs_lradc_probe(struct platform_device
> > *pdev) if (IS_ERR(lradc->base))
> >  		return PTR_ERR(lradc->base);
> >
> > +	lradc->clk = devm_clk_get(&pdev->dev, NULL);
> > +	clk_prepare_enable(lradc->clk);
> > +
>
> Wouldn't it make sense to enable the clock only when the device is
> opened to save power while not actually in use?

Sure. But I haven't analyzed yet if the IIO part of the driver also uses the 
delay units and - more important - when it use them.

@Marek: can you tell us, where the clock should be enabled in your part of the 
driver (if required)?

BTW: do we also need to get and enable the 24 MHz clock (used by the ADC 
itself)? I'm not sure if this clock is the "CLK_ANA24M" shown in 
their "Logical Diagram of Clock Domains". The datasheets also mention 
the "clk_xtal24m" clock for "analog 24 MHz clock domains". But does "Fixed 
clock domains" mean they are not switchable and thus always enabled?

Regards,
Juergen

-- 
Pengutronix e.K.                              | Juergen Beisert             |
Linux Solutions for Science and Industry      | http://www.pengutronix.de/  |
--
To unsubscribe from this list: send the line "unsubscribe linux-input" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html




[Index of Archives]     [Linux Media Devel]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]     [Linux Wireless Networking]     [Linux Omap]

  Powered by Linux