From: Peter Chen <hzpeterchen@gmail.com>
To: Stephen Boyd <stephen.boyd@linaro.org>
Cc: linux-usb@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
Andy Gross <andy.gross@linaro.org>,
Bjorn Andersson <bjorn.andersson@linaro.org>,
Neil Armstrong <narmstrong@baylibre.com>,
Arnd Bergmann <arnd@arndb.de>, Felipe Balbi <balbi@kernel.org>,
Peter Chen <peter.chen@nxp.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Kishon Vijay Abraham I <kishon@ti.com>
Subject: Re: [PATCH v6 23/25] usb: chipidea: Pullup D+ in device mode via phy APIs
Date: Fri, 13 Jan 2017 11:35:36 +0800 [thread overview]
Message-ID: <20170113033536.GA20723@b29397-desktop> (raw)
In-Reply-To: <148426139182.20672.2422337338087784924@sboyd-linaro>
On Thu, Jan 12, 2017 at 02:49:51PM -0800, Stephen Boyd wrote:
> Quoting Peter Chen (2017-01-12 01:50:40)
> > On Wed, Jan 11, 2017 at 04:19:53PM -0800, Stephen Boyd wrote:
> > > Quoting Peter Chen (2017-01-02 22:53:19)
> > > > On Wed, Dec 28, 2016 at 02:57:09PM -0800, Stephen Boyd wrote:
> > > > > If the phy supports it, call phy_set_mode() to pull up D+ when
> > > > > required by setting the mode to PHY_MODE_USB_DEVICE. If we want
> > > > > to remove the pullup, set the mode to PHY_MODE_USB_HOST.
> > > > >
> > > [..]
> > > > > diff --git a/drivers/usb/chipidea/udc.c b/drivers/usb/chipidea/udc.c
> > > > > index 0d532a724d48..6d61fa0689b0 100644
> > > > > --- a/drivers/usb/chipidea/udc.c
> > > > > +++ b/drivers/usb/chipidea/udc.c
> > > > > @@ -1609,10 +1610,15 @@ static int ci_udc_pullup(struct usb_gadget *_gadget, int is_on)
> > > > > return 0;
> > > > >
> > > > > pm_runtime_get_sync(&ci->gadget.dev);
> > > > > - if (is_on)
> > > > > + if (is_on) {
> > > > > + if (ci->phy)
> > > > > + phy_set_mode(ci->phy, PHY_MODE_USB_DEVICE);
> > > > > hw_write(ci, OP_USBCMD, USBCMD_RS, USBCMD_RS);
> > > > > - else
> > > > > + } else {
> > > > > hw_write(ci, OP_USBCMD, USBCMD_RS, 0);
> > > > > + if (ci->phy)
> > > > > + phy_set_mode(ci->phy, PHY_MODE_USB_HOST);
> > > > > + }
> > > > > pm_runtime_put_sync(&ci->gadget.dev);
> > > > >
> > > > > return 0;
> > > >
> > > > Would you describe the use case for it? Why not adding it at
> > > > role switch routine?
> > > >
> > >
> > > This is about pulling up D+. The phy I have requires that we manually
> > > pull up D+ by writing a ULPI register before we set the run/stop bit.
> >
> > Afaik, only controller can pull up dp when it is at device mode by
> > setting USBCMD_RS. At host mode, clear USBCMD_RS will only stopping
> > sending SoF from controller side.
> >
> > I am puzzled why you can pull up D+ by writing an ULPI register, perhaps,
> > your phy needs DP to change before switching the mode? Would you
> > double confirm that?
>
> With the boards I have, vbus is not routed to the phy. Instead, there's
> a vbus comparator on the PMIC where the vbus line from the usb
> receptacle is sent. The vbus extcon driver probes the comparator on the
> PMIC to see if vbus is present or not and then notifies extcon users
> when vbus changes.
>
> The ULPI register we write in the phy is a vendor specific register
> (called MISC_A) that has two bits. If you look at
> qcom_usb_hs_phy_set_mode() in this series you'll see that we set
> VBUSVLDEXTSEL and VBUSVLDEXT. VBUSVLDEXTSEL controls a mux in the phy
> that chooses between an internal comparator, in the case where vbus goes
> to the phy, or an external signal input to the phy, VBUSVLDEXT, to
> consider as the "session valid" signal. It looks like the session valid
> signal drives the D+ pullup resistor in the phy. These bits in MISC_A
> don't matter when the phy is in host mode.
>
> So when the board doesn't route vbus to the phy, we have to toggle the
> VBUSVLDEXT bit to signal to the phy that the vbus is there or not. I
> also see that we're not supposed to toggle the VBUSVLDEXTSEL bit when in
> "normal" operating mode. So perhaps we should do everything in the
> qcom_usb_hs_phy_set_mode() routine during the role switch as you
> suggest, except toggle the VBUSVLDEXT bit. Toggling the VBUSVLDEXT bit
> can be done via some new phy op when the extcon triggers?
Why not call phy_set_mode(phy, DEVICE) directly at ci_handle_vbus_change when
you get extcon vbus event?
--
Best Regards,
Peter Chen
next prev parent reply other threads:[~2017-01-13 3:34 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-28 22:56 [PATCH v6 00/25] Support qcom's HSIC USB and rewrite USB2 HS support Stephen Boyd
2016-12-28 22:56 ` [PATCH v6 01/25] of: device: Support loading a module with OF based modalias Stephen Boyd
2016-12-28 22:56 ` [PATCH v6 02/25] of: device: Export of_device_{get_modalias,uvent_modalias} to modules Stephen Boyd
2016-12-28 22:56 ` [PATCH v6 03/25] usb: ulpi: Support device discovery via DT Stephen Boyd
2017-01-19 6:33 ` Peter Chen
2017-01-19 7:39 ` Greg Kroah-Hartman
2016-12-28 22:56 ` [PATCH v6 04/25] usb: chipidea: Only read/write OTGSC from one place Stephen Boyd
2016-12-28 22:56 ` [PATCH v6 05/25] usb: chipidea: Handle extcon events properly Stephen Boyd
2016-12-28 22:56 ` [PATCH v6 06/25] usb: chipidea: Add platform flag for wrapper phy management Stephen Boyd
2016-12-28 22:56 ` [PATCH v6 07/25] usb: chipidea: Notify events when switching host mode Stephen Boyd
2016-12-28 22:56 ` [PATCH v6 08/25] usb: chipidea: Remove locking in ci_udc_start() Stephen Boyd
2016-12-28 22:56 ` [PATCH v6 09/25] usb: chipidea: Add support for ULPI PHY bus Stephen Boyd
2016-12-28 22:56 ` [PATCH v6 10/25] usb: chipidea: Consolidate extcon notifiers Stephen Boyd
2016-12-28 22:56 ` [PATCH v6 11/25] usb: chipidea: vbus event may exist before starting gadget Stephen Boyd
2017-01-03 8:00 ` Peter Chen
[not found] ` <148418115431.32258.10648057913784071156@sboyd-linaro>
2017-01-12 9:52 ` Peter Chen
2016-12-28 22:56 ` [PATCH v6 12/25] usb: chipidea: msm: Mark device as runtime pm active Stephen Boyd
2016-12-28 22:56 ` [PATCH v6 13/25] usb: chipidea: msm: Rely on core to override AHBBURST Stephen Boyd
2016-12-28 22:57 ` [PATCH v6 14/25] usb: chipidea: msm: Use hw_write_id_reg() instead of writel Stephen Boyd
2016-12-28 22:57 ` [PATCH v6 15/25] usb: chipidea: msm: Add proper clk and reset support Stephen Boyd
2016-12-28 22:57 ` [PATCH v6 16/25] usb: chipidea: msm: Mux over secondary phy at the right time Stephen Boyd
2016-12-28 22:57 ` [PATCH v6 17/25] usb: chipidea: msm: Restore wrapper settings after reset Stephen Boyd
2016-12-28 22:57 ` [PATCH v6 18/25] usb: chipidea: msm: Make platform data driver local instead of global Stephen Boyd
2016-12-28 22:57 ` [PATCH v6 19/25] usb: chipidea: msm: Add reset controller for PHY POR bit Stephen Boyd
2016-12-28 22:57 ` [PATCH v6 20/25] usb: chipidea: msm: Handle phy power states Stephen Boyd
2016-12-28 22:57 ` [PATCH v6 21/25] usb: chipidea: msm: Be silent on probe defer errors Stephen Boyd
2016-12-28 22:57 ` [PATCH v6 22/25] usb: chipidea: Drop lock across event_notify during gadget stop Stephen Boyd
2017-01-03 6:46 ` Peter Chen
2016-12-28 22:57 ` [PATCH v6 23/25] usb: chipidea: Pullup D+ in device mode via phy APIs Stephen Boyd
2017-01-03 6:53 ` Peter Chen
[not found] ` <148418039309.32258.7247753739063801774@sboyd-linaro>
2017-01-12 9:50 ` Peter Chen
[not found] ` <148426139182.20672.2422337338087784924@sboyd-linaro>
2017-01-13 3:35 ` Peter Chen [this message]
[not found] ` <148433778067.32719.6179204976256776867@sboyd-linaro>
2017-01-16 3:45 ` Peter Chen
[not found] ` <148467591341.23457.3638889856786813589@sboyd-linaro>
2017-01-18 7:34 ` Peter Chen
2017-01-18 20:54 ` Stephen Boyd
2017-01-18 20:57 ` Rob Herring
2017-01-19 6:29 ` Peter Chen
2016-12-28 22:57 ` [PATCH v6 24/25] phy: Add support for Qualcomm's USB HSIC phy Stephen Boyd
2016-12-28 22:57 ` [PATCH v6 25/25] phy: Add support for Qualcomm's USB HS phy Stephen Boyd
2017-01-20 7:40 ` [PATCH v6 00/25] Support qcom's HSIC USB and rewrite USB2 HS support Peter Chen
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