[linux-yocto] [PATCH 10/29] usb: dwc3: pci: Enable/disable ulpi phy refclk

[Kamble, Nitin A]

On 4/7/2014 8:18 AM, rebecca.swee.fun.chang at intel.com wrote:
> From: Maurice Petallo <mauricex.r.petallo at intel.com>
>
> Due to power saving purpose, BIOS disabled ulpi phy refclk by default.
> Hence, the refclk will only be enabled during device/driver probing.
> and disabled during driver removal.
If this commit is not already pushed upstream, I would suggest to 
improve the wording
of the commit message here. I will replace the commit message with 
something like this.

For the purpose of saving power, BIOS has disabled "ulpi phy refclk" by 
default.
Hence, for the conservation of power, the "refclk" is enabled only at 
the time of
device/driver probing, and is disabled at the time of of driver removal.

Nitin

> Signed-off-by: Maurice Petallo <mauricex.r.petallo at intel.com>
> Signed-off-by: Chew, Chiau Ee <chiau.ee.chew at intel.com>
> ---
>   drivers/usb/dwc3/dwc3-pci.c |   23 +++++++++++++++++++++++
>   1 file changed, 23 insertions(+)
>
> diff --git a/drivers/usb/dwc3/dwc3-pci.c b/drivers/usb/dwc3/dwc3-pci.c
> index 2357c4e..4ebe49a 100644
> --- a/drivers/usb/dwc3/dwc3-pci.c
> +++ b/drivers/usb/dwc3/dwc3-pci.c
> @@ -51,6 +51,10 @@
>   #define PCI_DEVICE_ID_INTEL_BYT		0x0f37
>   #define PCI_DEVICE_ID_INTEL_MRFLD	0x119e
>   
> +#define DWC3_PCI_GEN_REGRW1			0xa0
> +#define DWC3_PCI_GEN_REGRW1_REFCLK_EN(n)	(n & 0xfffdffff)
> +#define DWC3_PCI_GEN_REGRW1_REFCLK_DIS(n)	(n | 0x020000)
> +
>   struct dwc3_pci {
>   	struct device		*dev;
>   	struct platform_device	*dwc3;
> @@ -112,6 +116,19 @@ err1:
>   	return ret;
>   }
>   
> +static void dwc3_pci_ulpiphy_refclk(struct pci_dev *pci, int enable)
> +{
> +	u32 val;
> +
> +	pci_read_config_dword(pci, DWC3_PCI_GEN_REGRW1, &val);
> +	if (enable)
> +		val = DWC3_PCI_GEN_REGRW1_REFCLK_EN(val);
> +	else
> +		val = DWC3_PCI_GEN_REGRW1_REFCLK_DIS(val);
> +
> +	pci_write_config_dword(pci, DWC3_PCI_GEN_REGRW1, val);
> +}
> +
>   static int dwc3_pci_probe(struct pci_dev *pci,
>   		const struct pci_device_id *id)
>   {
> @@ -183,6 +200,9 @@ static int dwc3_pci_probe(struct pci_dev *pci,
>   		goto err3;
>   	}
>   
> +	/* enable ulpi phy refclk */
> +	dwc3_pci_ulpiphy_refclk(pci, 1);
> +
>   	return 0;
>   
>   err3:
> @@ -198,6 +218,9 @@ static void dwc3_pci_remove(struct pci_dev *pci)
>   {
>   	struct dwc3_pci	*glue = pci_get_drvdata(pci);
>   
> +	/* disable ulpi phy refclk */
> +	dwc3_pci_ulpiphy_refclk(pci, 0);
> +
>   	platform_device_unregister(glue->dwc3);
>   	platform_device_unregister(glue->usb2_phy);
>   	platform_device_unregister(glue->usb3_phy);