From: Bin Liu <b-liu@ti.com>
To: David Lechner <david@lechnology.com>
Cc: <petr@barix.com>, <sergei.shtylyov@cogentembedded.com>,
<khilman@kernel.org>, <nsekhar@ti.com>,
Rob Herring <robh+dt@kernel.org>, Pawel Moll <pawel.moll@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Ian Campbell <ijc+devicetree@hellion.org.uk>,
Kumar Gala <galak@codeaurora.org>,
Kishon Vijay Abraham I <kishon@ti.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Alan Stern <stern@rowland.harvard.edu>,
Lee Jones <lee.jones@linaro.org>, <devicetree@vger.kernel.org>,
<linux-kernel@vger.kernel.org>, <linux-usb@vger.kernel.org>
Subject: Re: [PATCH v4 3/7] phy: Add set_mode callback
Date: Wed, 4 May 2016 13:39:03 -0500 [thread overview]
Message-ID: <20160504183903.GB27414@uda0271908> (raw)
In-Reply-To: <572A3D74.3080907@lechnology.com>
On Wed, May 04, 2016 at 01:20:36PM -0500, David Lechner wrote:
> On 05/04/2016 01:10 PM, Bin Liu wrote:
> >Hi,
> >
> >On Thu, Apr 14, 2016 at 01:35:14PM -0500, David Lechner wrote:
> >>The initial use for this is for PHYs that have a mode related to USB OTG.
> >>There are several SoCs (e.g. TI OMAP and DA8xx) that have a mode setting
> >>in the USB PHY to override OTG VBUS and ID signals.
> >>
> >>Of course, the enum can be expaned in the future to include modes for
> >>other types of PHYs as well.
> >>
> >>Suggested-by: Kishon Vijay Abraham I <kishon@ti.com>
> >>Signed-off-by: David Lechner <david@lechnology.com>
> >>---
> >>
> >>v4 changes:
> >>
> >>* This is a new patch to avoid exporting a symbol from the phy-da8xx-usb driver.
> >>
> >>
> >> drivers/phy/phy-core.c | 15 +++++++++++++++
> >> include/linux/phy/phy.h | 15 +++++++++++++++
> >> 2 files changed, 30 insertions(+)
> >>
> >>diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
> >>index e7e574d..fe0344c 100644
> >>--- a/drivers/phy/phy-core.c
> >>+++ b/drivers/phy/phy-core.c
> >>@@ -342,6 +342,21 @@ int phy_power_off(struct phy *phy)
> >> }
> >> EXPORT_SYMBOL_GPL(phy_power_off);
> >>
> >>+int phy_set_mode(struct phy *phy, enum phy_mode mode)
> >>+{
> >>+ int ret;
> >>+
> >>+ if (!phy || !phy->ops->set_mode)
> >>+ return 0;
> >>+
> >>+ mutex_lock(&phy->mutex);
> >>+ ret = phy->ops->set_mode(phy, mode);
> >>+ mutex_unlock(&phy->mutex);
> >>+
> >>+ return ret;
> >>+}
> >>+EXPORT_SYMBOL_GPL(phy_set_mode);
> >
> >Sorry for my late comments, have been busy on other things.
> >
> >As I commented in v2, isn't it a better idea to not adding this callback
> >and let the da8xx phy driver set the mode register in _probe() based on
> >DT dr_mode?
> >
> >musb core only calls the *optional* _set_mode() during init, so I don't
> >see any problem if the phy set the mode in its probe.
> >
> >Regards,
> >-Bin.
> >
>
> As was already discussed, the mode can be changed via sysfs as well
> as during probe, so this callback is needed for that case.
Ahh, it seems we have discussed this... I keep forgetting things...
>
> This is something I actually plan on using because the device I am
> using (LEGO MINDSTORMS EV3) is not wired for OTG, so the callback is
> needed to override the ID and VBUS signals when switching between
> host and peripheral mode.
Have you already tested this? I never tried changing mode via sysfs, but
by quickly reviewing the code, I am wondering how it works. the core
only calls ops->set_mode() but nothing else. To really switch the mode,
the driver has to talk to the root hub, and manipulate the SESSION
bit...
Regards,
-Bin.
next prev parent reply other threads:[~2016-05-04 18:40 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-14 18:35 [PATCH v4 0/7] da8xx USB PHY (was da8xx USB clocks) David Lechner
2016-04-14 18:35 ` [PATCH v4 1/7] mfd: da8xx-cfgchip: New header file for CFGCHIP registers David Lechner
2016-04-25 14:08 ` Lee Jones
2016-04-14 18:35 ` [PATCH v4 2/7] dt-bindings: Add bindings for phy-da8xx-usb David Lechner
2016-04-15 10:48 ` Sergei Shtylyov
2016-04-15 16:13 ` David Lechner
2016-04-15 17:05 ` Sergei Shtylyov
2016-04-14 18:35 ` [PATCH v4 3/7] phy: Add set_mode callback David Lechner
2016-05-04 18:10 ` Bin Liu
2016-05-04 18:20 ` David Lechner
2016-05-04 18:39 ` Bin Liu [this message]
2016-05-04 19:48 ` David Lechner
2016-05-09 22:47 ` David Lechner
2016-04-14 18:35 ` [PATCH v4 4/7] phy: da8xx-usb: new driver for DA8xx SoC USB PHY David Lechner
2016-04-19 8:03 ` Kishon Vijay Abraham I
2016-04-14 18:35 ` [PATCH v4 5/7] usb: ohci-da8xx: Remove code that references mach David Lechner
2016-04-14 18:35 ` [PATCH v4 6/7] usb: musb: da8xx: Use devm in probe David Lechner
2016-04-14 18:35 ` [PATCH v4 7/7] usb: musb: da8xx: Remove mach code David Lechner
2016-05-04 16:24 ` [PATCH v4 0/7] da8xx USB PHY (was da8xx USB clocks) David Lechner
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