On 10/26/2016 05:40 PM, David Lechner wrote:
> On 10/26/2016 05:58 AM, Alexandre Bailon wrote:
>> If we configure the da8xx OTG phy in OTG mode, neither device or host
>> mode will work. That is because the PHY is not able to detect and notify
>> the driver that value of ID pin changed.
>> To work despite this hardware limitation, the da8xx glue implement a
>> workaround.
>> But to work, the workaround require the VBUS sense and the session end
>> comparator to enabled.
>> Enable them if the phy is configured in OTG mode.
>>
>> Signed-off-by: Alexandre Bailon <abailon@xxxxxxxxxxxx>
>> ---
>> drivers/phy/phy-da8xx-usb.c | 17 ++++++++++++-----
>> 1 file changed, 12 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/phy/phy-da8xx-usb.c b/drivers/phy/phy-da8xx-usb.c
>> index 32ae78c..fd39292 100644
>> --- a/drivers/phy/phy-da8xx-usb.c
>> +++ b/drivers/phy/phy-da8xx-usb.c
>> @@ -93,24 +93,31 @@ static int da8xx_usb20_phy_power_off(struct phy *phy)
>> static int da8xx_usb20_phy_set_mode(struct phy *phy, enum phy_mode mode)
>> {
>> struct da8xx_usb_phy *d_phy = phy_get_drvdata(phy);
>> + int ret;
>> u32 val;
>>
>> + ret = regmap_read(d_phy->regmap, CFGCHIP(2), &val);
>> + if (ret)
>> + return ret;
>> +
>> + val &= ~CFGCHIP2_OTGMODE_MASK;
>> +
>> switch (mode) {
>> case PHY_MODE_USB_HOST: /* Force VBUS valid, ID = 0 */
>> - val = CFGCHIP2_OTGMODE_FORCE_HOST;
>> + val |= CFGCHIP2_OTGMODE_FORCE_HOST;
>> break;
>> case PHY_MODE_USB_DEVICE: /* Force VBUS valid, ID = 1 */
>> - val = CFGCHIP2_OTGMODE_FORCE_DEVICE;
>> + val |= CFGCHIP2_OTGMODE_FORCE_DEVICE;
>> break;
>> case PHY_MODE_USB_OTG: /* Don't override the VBUS/ID
>> comparators */
>> - val = CFGCHIP2_OTGMODE_NO_OVERRIDE;
>> + val |= CFGCHIP2_OTGMODE_NO_OVERRIDE |
>> + CFGCHIP2_SESENDEN | CFGCHIP2_VBDTCTEN;
>
> The AM1808 TRM indicates that CFGCHIP2_SESENDEN and CFGCHIP2_VBDTCTEN
> (and CFGCHIP2_DATPOL) should be on for normal operation of the USB 2.0
> PHY. They do not appear to be associated with the OTG mode specifically.
I agree but the function assigned to these bit is highly tied to OTG.
And in TI BSP, there is a comment that let me think that is only needed
for OTG.
/*
* We have to override VBUS/ID signals when MUSB is configured into the
* host-only mode -- ID pin will float if no cable is connected, so the
* controller won't be able to drive VBUS thinking that it's a B-device.
* Otherwise, we want to use the OTG mode and enable VBUS comparators.
*/
cfgchip2 &= ~CFGCHIP2_OTGMODE;
#ifdef CONFIG_USB_MUSB_HOST
cfgchip2 |= CFGCHIP2_FORCE_HOST;
#else
cfgchip2 |= CFGCHIP2_SESENDEN | CFGCHIP2_VBDTCTEN;
#endif
>
> It seems to me that it would be more appropriate to set these in
> da8xx_usb20_phy_power_on() instead of here in da8xx_usb20_phy_set_mode().
I tried both the phy forced in device or host mode with theses bit set
or clear and I haven't see any issues, so I think we could set them in
da8xx_usb20_phy_power_on() as you suggested.
>
>
>> break;
>> default:
>> return -EINVAL;
>> }
>>
>> - regmap_write_bits(d_phy->regmap, CFGCHIP(2), CFGCHIP2_OTGMODE_MASK,
>> - val);
>> + regmap_write(d_phy->regmap, CFGCHIP(2), val);
>>
>> return 0;
>> }
>>
>
> Also cc'ing phy maintainer since this is a phy driver.
>
>
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