Re: [PATCHv9 8/8] ARM: OMAP4: USB: power down MUSB PHY if not used

[kishon <kishon@ti.com>]

Hi,

On Monday 22 October 2012 02:37 PM, Felipe Balbi wrote:
> On Mon, Oct 22, 2012 at 02:24:30PM +0530, kishon wrote:
>> Hi,
>>
>> On Thursday 18 October 2012 08:09 PM, Tero Kristo wrote:
>>> On Thu, 2012-10-18 at 16:53 +0300, Felipe Balbi wrote:
>>>> hi,
>>>>
>>>> On Thu, Oct 18, 2012 at 03:18:04PM +0300, Tero Kristo wrote:
>>>>>>> +static int __init omap4430_phy_power_down(void)
>>>>>>> +{
>>>>>>> +	void __iomem *ctrl_base;
>>>>>>> +
>>>>>>> +	if (!cpu_is_omap44xx())
>>>>>>> +		return 0;
>>>>>>> +
>>>>>>> +	ctrl_base = ioremap(OMAP443X_SCM_BASE, SZ_1K);
>>>>>>> +	if (!ctrl_base) {
>>>>>>> +		pr_err("control module ioremap failed\n");
>>>>>>> +		return -ENOMEM;
>>>>>>> +	}
>>>>>>> +
>>>>>>> +	/* Power down the phy */
>>>>>>> +	__raw_writel(PHY_PD, ctrl_base + CONTROL_DEV_CONF);
>>>>>>> +
>>>>>>> +	iounmap(ctrl_base);
>>>>>>> +
>>>>>>> +	return 0;
>>>>>>> +}
>>>>>>> +early_initcall(omap4430_phy_power_down);
>>>>>>> +#endif
>>>>>>
>>>>>> I think you could do it even if the driver is enabled.
>>>>>
>>>>> Actually not at least now, it looks like the driver is not controlling
>>>>> this bit at all, so the driver would fail if we do this.
>>>>
>>>> then we can consider that a bug in the driver. Kishon, I thought you had
>>>> added SCM address space to PHY driver for this particular reason until
>>>> we get SCM driver, wasn't it ??
>>>
>>> Yes, I would say its a bug in the driver.
>>
>> No. It's done in the driver (omap_usb_phy_power() in
>> drivers/usb/phy/omap-usb2.c). We explicitly power off the phy during
>> probe in the driver.
>
> so you also handle enabling the IP later when you need ? That's great,
> it means we can do the above unconditionally, driver enabled or not.

yes.

Thanks
Kishon