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From: Bin Liu <b-liu-l0cyMroinI0@public.gmane.org>
To: David Lechner <david-nq/r/kbU++upp/zk7JDF2g@public.gmane.org>
Cc: petr-Qh/3xLP0EvwAvxtiuMwx3w@public.gmane.org,
	sergei.shtylyov-M4DtvfQ/ZS1MRgGoP+s0PdBPR1lH4CV8@public.gmane.org,
	khilman-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org,
	nsekhar-l0cyMroinI0@public.gmane.org,
	Rob Herring <robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	Pawel Moll <pawel.moll-5wv7dgnIgG8@public.gmane.org>,
	Mark Rutland <mark.rutland-5wv7dgnIgG8@public.gmane.org>,
	Ian Campbell
	<ijc+devicetree-KcIKpvwj1kUDXYZnReoRVg@public.gmane.org>,
	Kumar Gala <galak-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>,
	Kishon Vijay Abraham I <kishon-l0cyMroinI0@public.gmane.org>,
	Greg Kroah-Hartman
	<gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org>,
	Alan Stern
	<stern-nwvwT67g6+6dFdvTe/nMLpVzexx5G7lz@public.gmane.org>,
	Lee Jones <lee.jones-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>,
	devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.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-nq/r/kbU++upp/zk7JDF2g@public.gmane.org>

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-l0cyMroinI0@public.gmane.org>
> >>Signed-off-by: David Lechner <david-nq/r/kbU++upp/zk7JDF2g@public.gmane.org>
> >>---
> >>
> >>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.

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  parent reply	other threads:[~2016-05-04 18:39 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
     [not found]   ` <1460658919-4965-2-git-send-email-david-nq/r/kbU++upp/zk7JDF2g@public.gmane.org>
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
     [not found]     ` <5710C6E1.8010401-M4DtvfQ/ZS1MRgGoP+s0PdBPR1lH4CV8@public.gmane.org>
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
     [not found]   ` <1460658919-4965-4-git-send-email-david-nq/r/kbU++upp/zk7JDF2g@public.gmane.org>
2016-05-04 18:10     ` Bin Liu
2016-05-04 18:20       ` David Lechner
     [not found]         ` <572A3D74.3080907-nq/r/kbU++upp/zk7JDF2g@public.gmane.org>
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
     [not found] ` <1460658919-4965-1-git-send-email-david-nq/r/kbU++upp/zk7JDF2g@public.gmane.org>
2016-05-04 16:24   ` [PATCH v4 0/7] da8xx USB PHY (was da8xx USB clocks) David Lechner

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