linux-stable/include/linux/usb/typec_mux.h
Heikki Krogerus 3370db3519 usb: typec: Registering real device entries for the muxes
Registering real device entries (struct device) for the mode
muxes as well as for the orientation switches.

The Type-C mux code was deliberately attempting to avoid
creation of separate device entries for the orientation
switch and the mode switch (alternate modes) because they
are not physical devices. They are functions of a single
physical multiplexer/demultiplexer switch device.

Unfortunately because of the dependency we still have on the
underlying mux device driver, we had to put in hacks like
the one in the commit 3e3b81965c ("usb: typec: mux: Take
care of driver module reference counting") to make sure the
driver does not disappear from underneath us. Even with
those hacks we were still left with a potential NUll pointer
dereference scenario, so just creating the device entries,
and letting the core take care of the dependencies. No more
hacks needed.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Tested-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-06-03 10:55:38 +02:00

50 lines
1.4 KiB
C

// SPDX-License-Identifier: GPL-2.0
#ifndef __USB_TYPEC_MUX
#define __USB_TYPEC_MUX
#include <linux/usb/typec.h>
struct device;
struct typec_mux;
struct typec_switch;
struct fwnode_handle;
typedef int (*typec_switch_set_fn_t)(struct typec_switch *sw,
enum typec_orientation orientation);
struct typec_switch_desc {
struct fwnode_handle *fwnode;
typec_switch_set_fn_t set;
void *drvdata;
};
struct typec_switch *typec_switch_get(struct device *dev);
void typec_switch_put(struct typec_switch *sw);
struct typec_switch *
typec_switch_register(struct device *parent,
const struct typec_switch_desc *desc);
void typec_switch_unregister(struct typec_switch *sw);
void typec_switch_set_drvdata(struct typec_switch *sw, void *data);
void *typec_switch_get_drvdata(struct typec_switch *sw);
typedef int (*typec_mux_set_fn_t)(struct typec_mux *mux, int state);
struct typec_mux_desc {
struct fwnode_handle *fwnode;
typec_mux_set_fn_t set;
void *drvdata;
};
struct typec_mux *
typec_mux_get(struct device *dev, const struct typec_altmode_desc *desc);
void typec_mux_put(struct typec_mux *mux);
struct typec_mux *
typec_mux_register(struct device *parent, const struct typec_mux_desc *desc);
void typec_mux_unregister(struct typec_mux *mux);
void typec_mux_set_drvdata(struct typec_mux *mux, void *data);
void *typec_mux_get_drvdata(struct typec_mux *mux);
#endif /* __USB_TYPEC_MUX */