netdev - Re: [PATCH 6/7] fsl_pmc: Add API to enable device as wakeup event source

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Date:	Mon, 7 Nov 2011 19:22:36 +0800
From:	Zhao Chenhui <chenhui.zhao@...escale.com>
To:	Scott Wood <scottwood@...escale.com>
CC:	<linuxppc-dev@...ts.ozlabs.org>, <netdev@...r.kernel.org>,
	<leoli@...escale.com>
Subject: Re: [PATCH 6/7] fsl_pmc: Add API to enable device as wakeup event
 source

On Fri, Nov 04, 2011 at 04:14:25PM -0500, Scott Wood wrote:
> On 11/04/2011 07:39 AM, Zhao Chenhui wrote:
> > @@ -45,6 +46,72 @@ static int has_lossless;
> >   * code can be compatible with both 32-bit & 36-bit */
> >  extern void mpc85xx_enter_deep_sleep(u64 ccsrbar, u32 powmgtreq);
> >  
> > +#ifdef CONFIG_FSL_PMC
> > +/**
> > + * pmc_enable_wake - enable OF device as wakeup event source
> > + * @pdev: platform device affected
> > + * @state: PM state from which device will issue wakeup events
> > + * @enable: True to enable event generation; false to disable
> > + *
> > + * This enables the device as a wakeup event source, or disables it.
> > + *
> > + * RETURN VALUE:
> > + * 0 is returned on success
> > + * -EINVAL is returned if device is not supposed to wake up the system
> > + * Error code depending on the platform is returned if both the platform and
> > + * the native mechanism fail to enable the generation of wake-up events
> > + */
> > +int pmc_enable_wake(struct platform_device *pdev,
> > +				suspend_state_t state, bool enable)
> 
> "pmc" is too generic for a global function.  If this can be either
> enable or disable, perhaps it should be something like
> mpc85xx_pmc_set_wake().
> 
> > +{
> > +	int ret = 0;
> > +	struct device_node *clk_np;
> > +	u32 *pmcdr_mask;
> > +
> > +	if (!pmc_regs) {
> > +		printk(KERN_WARNING "PMC is unavailable\n");
> > +		return -ENOMEM;
> > +	}
> 
> -ENOMEM is not appropriate here, maybe -ENODEV?
> 
> Should print __func__ so the user knows what's complaining.
> 
> > +	if (enable && !device_may_wakeup(&pdev->dev))
> > +		return -EINVAL;
> > +
> > +	clk_np = of_parse_phandle(pdev->dev.of_node, "clk-handle", 0);
> > +	if (!clk_np)
> > +		return -EINVAL;
> > +
> > +	pmcdr_mask = (u32 *)of_get_property(clk_np, "fsl,pmcdr-mask", NULL);
> > +	if (!pmcdr_mask) {
> > +		ret = -EINVAL;
> > +		goto out;
> > +	}
> > +
> > +	/* clear to enable clock in low power mode */
> > +	if (enable)
> > +		clrbits32(&pmc_regs->pmcdr, *pmcdr_mask);
> > +	else
> > +		setbits32(&pmc_regs->pmcdr, *pmcdr_mask);
> 
> We should probably initialize PMCDR to all bits set (or at least all
> ones we know are valid) -- the default should be "not a wakeup source".

I think it should be initialized in u-boot.

> 
> > +/**
> > + * pmc_enable_lossless - enable lossless ethernet in low power mode
> > + * @enable: True to enable event generation; false to disable
> > + */
> > +void pmc_enable_lossless(int enable)
> > +{
> > +	if (enable && has_lossless)
> > +		setbits32(&pmc_regs->pmcsr, PMCSR_LOSSLESS);
> > +	else
> > +		clrbits32(&pmc_regs->pmcsr, PMCSR_LOSSLESS);
> > +}
> > +EXPORT_SYMBOL_GPL(pmc_enable_lossless);
> > +#endif
> 
> Won't we overwrite this later?
> 
> -Scott

Do you have any idea?

-chenhui

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