Re: [v13 PATCH 2/5] phy: Add USB Type-C PHY driver for rk3399

[Guenter Roeck]

Hi Chris,

On Sun, Aug 21, 2016 at 9:52 PM, Chris <zywang33@xxxxxxx> wrote:
> Hi Guenter
>
[ ... ]

>>> +static int rockchip_usb3_phy_power_on(struct phy *phy)
>>> +{
>>> +       struct rockchip_typec_phy *tcphy = phy_get_drvdata(phy);
>>> +       struct rockchip_usb3phy_port_cfg *cfg = &tcphy->port_cfgs;
>>> +       const struct usb3phy_reg *reg = &cfg->pipe_status;
>>> +       int timeout, new_mode, ret = 0;
>>> +       u32 val;
>>> +
>>> +       mutex_lock(&tcphy->lock);
>>> +
>>> +       new_mode = tcphy_get_mode(tcphy);
>>> +       if (new_mode < 0) {
>>> +               ret = new_mode;
>>> +               goto unlock_ret;
>>> +       }
>>> +
>>> +       /* DP-only mode; fall back to USB2 */
>>> +       if (!(new_mode & (MODE_DFP_USB | MODE_UFP_USB)))
>>> +               goto unlock_ret;
>>> +
>>
>> The rest of the code (calling tcphy_phy_init(), waiting for pipe
>> ready) is not needed in this case ?
>
>
> If there is only DP, the tcphy_phy_init will be called by DP controller, and
> the pipe is for USB3, so do not need do anything, just return a "fake"
> success here.
> And the usb phy power off do nothing. Just make USB  controller happier.
>

Yes, you are right. It is a bit confusing (and I had overlooked) that
MODE_DFP_USB is set for both USB2 and USB3 if DP isn't active, but if
DP is active it is only set for USB3.

Guenter