Re: [PATCH v4 3/7] phy: Add set_mode callback

From: David Lechner
Date: Wed May 04 2016 - 14:20:42 EST

On 05/04/2016 01:10 PM, Bin Liu wrote:

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@xxxxxx>
Signed-off-by: David Lechner <david@xxxxxxxxxxxxxx>

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)

+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;

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.


As was already discussed, the mode can be changed via sysfs as well as during probe, so this callback is needed for that case.

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.