Re: [PATCH v2 2/7] usb: dwc3: adapt dwc3 core to use Generic PHY Framework

[Kishon Vijay Abraham I <kishon@ti.com>]

Hi,

On Wednesday 16 October 2013 06:48 PM, Roger Quadros wrote:
> Hi,
> 
> On 10/15/2013 10:54 PM, Kishon Vijay Abraham I wrote:
>> Adapted dwc3 core to use the Generic PHY Framework. So for init, exit,
>> power_on and power_off the following APIs are used phy_init(), phy_exit(),
>> phy_power_on() and phy_power_off().
>>
>> However using the old USB phy library wont be removed till the PHYs of all
>> other SoC's using dwc3 core is adapted to the Generic PHY Framework.
>>
>> Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
>> ---
>>  Documentation/devicetree/bindings/usb/dwc3.txt |    6 ++-
>>  drivers/usb/dwc3/Kconfig                       |    1 +
>>  drivers/usb/dwc3/core.c                        |   52 ++++++++++++++++++++++++
>>  drivers/usb/dwc3/core.h                        |    7 ++++
>>  drivers/usb/dwc3/platform_data.h               |    2 +
>>  5 files changed, 66 insertions(+), 2 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/usb/dwc3.txt b/Documentation/devicetree/bindings/usb/dwc3.txt
>> index e807635..471366d 100644
>> --- a/Documentation/devicetree/bindings/usb/dwc3.txt
>> +++ b/Documentation/devicetree/bindings/usb/dwc3.txt
>> @@ -6,11 +6,13 @@ Required properties:
>>   - compatible: must be "snps,dwc3"
>>   - reg : Address and length of the register set for the device
>>   - interrupts: Interrupts used by the dwc3 controller.
>> +
>> +Optional properties:
>>   - usb-phy : array of phandle for the PHY device.  The first element
>>     in the array is expected to be a handle to the USB2/HS PHY and
>>     the second element is expected to be a handle to the USB3/SS PHY
>> -
>> -Optional properties:
>> + - phys: from the *Generic PHY* bindings
>> + - phy-names: from the *Generic PHY* bindings
>>   - tx-fifo-resize: determines if the FIFO *has* to be reallocated.
>>  
>>  This is usually a subnode to DWC3 glue to which it is connected.
>> diff --git a/drivers/usb/dwc3/Kconfig b/drivers/usb/dwc3/Kconfig
>> index 8e385b4..64eed6f 100644
>> --- a/drivers/usb/dwc3/Kconfig
>> +++ b/drivers/usb/dwc3/Kconfig
>> @@ -2,6 +2,7 @@ config USB_DWC3
>>  	tristate "DesignWare USB3 DRD Core Support"
>>  	depends on (USB || USB_GADGET) && HAS_DMA
>>  	select USB_PHY
>> +	select GENERIC_PHY
>>  	select USB_XHCI_PLATFORM if USB_SUPPORT && USB_XHCI_HCD
>>  	help
>>  	  Say Y or M here if your system has a Dual Role SuperSpeed
>> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
>> index cb91d70..28bfa5b 100644
>> --- a/drivers/usb/dwc3/core.c
>> +++ b/drivers/usb/dwc3/core.c
>> @@ -82,6 +82,12 @@ static void dwc3_core_soft_reset(struct dwc3 *dwc)
>>  
>>  	usb_phy_init(dwc->usb2_phy);
>>  	usb_phy_init(dwc->usb3_phy);
>> +
>> +	if (dwc->usb2_generic_phy)
>> +		phy_init(dwc->usb2_generic_phy);
>> +	if (dwc->usb3_generic_phy)
>> +		phy_init(dwc->usb3_generic_phy);
>> +
> 
> dwc3_core_soft_reset() is called from dwc3_core_init() which is called from
> dwc3_probe() but before the PHYs are initialized.
> 
> This will cause phy power_on() to be called before phy_init() which is wrong.
> 
>>  	mdelay(100);
>>  
>>  	/* Clear USB3 PHY reset */
>> @@ -343,6 +349,11 @@ static void dwc3_core_exit(struct dwc3 *dwc)
>>  {
>>  	usb_phy_shutdown(dwc->usb2_phy);
>>  	usb_phy_shutdown(dwc->usb3_phy);
>> +
>> +	if (dwc->usb2_generic_phy)
>> +		phy_power_off(dwc->usb2_generic_phy);
>> +	if (dwc->usb3_generic_phy)
>> +		phy_power_off(dwc->usb3_generic_phy);
>>  }
>>  
>>  #define DWC3_ALIGN_MASK		(16 - 1)
>> @@ -439,6 +450,26 @@ static int dwc3_probe(struct platform_device *pdev)
>>  		dwc->usb3_phy = devm_usb_get_phy(dev, USB_PHY_TYPE_USB3);
>>  	}
>>  
>> +	count = of_property_match_string(node, "phy-names", "usb2-phy");
>> +	if (count >= 0 || (pdata && pdata->usb2_generic_phy)) {
>> +		dwc->usb2_generic_phy = devm_phy_get(dev, "usb2-phy");
>> +		if (IS_ERR(dwc->usb2_generic_phy)) {
>> +			dev_err(dev, "no usb2 phy configured yet");
>> +			return PTR_ERR(dwc->usb2_generic_phy);
>> +		}
>> +		dwc->usb2_phy = NULL;
>> +	}
>> +
>> +	count = of_property_match_string(node, "phy-names", "usb3-phy");
>> +	if (count >= 0 || (pdata && pdata->usb3_generic_phy)) {
>> +		dwc->usb3_generic_phy = devm_phy_get(dev, "usb3-phy");
>> +		if (IS_ERR(dwc->usb3_generic_phy)) {
>> +			dev_err(dev, "no usb3 phy configured yet");
>> +			return PTR_ERR(dwc->usb3_generic_phy);
>> +		}
>> +		dwc->usb3_phy = NULL;
>> +	}
>> +
> 
> There are a couple of issues here.
> - The above code must be executed only if it node is valid.

of_property_match_string will give a error value if the node is not present.
*count >= 0* can take care of this.
> - We must either get both PHYs via old method or via new method and not support mix matching
> them. e.g. it is possible with this code that usb2_phy is set and usb3_generic_phy is set.

Why? As long as both the frameworks co-exist (and we support both in dwc3), I
don't see any reason why we shouldn't allow it. We can avoid adding a few more
checks by leaving it the way it is currently.

Thanks
Kishon