linux/drivers/base/pinctrl.c
Johan Hovold ed032c1bed driver core: fix automatic pinctrl management
Commit ab78029ecc ("drivers/pinctrl: grab default handles from device
core") added automatic pin-control management to driver core by looking
up and setting any default pinctrl state found in device tree while a
device is being probed.

This obviously runs into problems as soon as device-tree nodes are
reused for child devices which are later also probed as pins would
already have been claimed by the ancestor device.

For example if a USB host controller claims a pin, its root hub would
consequently fail to probe when its device-tree node is set to the node
of the controller:

    pinctrl-single 48002030.pinmux: pin PIN204 already requested by 48064800.ehci; cannot claim for usb1
    pinctrl-single 48002030.pinmux: pin-204 (usb1) status -22
    pinctrl-single 48002030.pinmux: could not request pin 204 (PIN204) from group usb_dbg_pins  on device pinctrl-single
    usb usb1: Error applying setting, reverse things back
    usb: probe of usb1 failed with error -22

Fix this by checking the new of_node_reused flag and skipping automatic
pinctrl configuration during probe if set.

Note that the flag is checked in driver core rather than in pinctrl
(e.g. in pinctrl_dt_to_map()) which would specifically have prevented
intentional use of a parent's pinctrl properties by a child device
(should such a need ever arise).

Fixes: ab78029ecc ("drivers/pinctrl: grab default handles from device core")
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-13 11:07:32 +02:00

107 lines
2.7 KiB
C

/*
* Driver core interface to the pinctrl subsystem.
*
* Copyright (C) 2012 ST-Ericsson SA
* Written on behalf of Linaro for ST-Ericsson
* Based on bits of regulator core, gpio core and clk core
*
* Author: Linus Walleij <linus.walleij@linaro.org>
*
* License terms: GNU General Public License (GPL) version 2
*/
#include <linux/device.h>
#include <linux/pinctrl/devinfo.h>
#include <linux/pinctrl/consumer.h>
#include <linux/slab.h>
/**
* pinctrl_bind_pins() - called by the device core before probe
* @dev: the device that is just about to probe
*/
int pinctrl_bind_pins(struct device *dev)
{
int ret;
if (dev->of_node_reused)
return 0;
dev->pins = devm_kzalloc(dev, sizeof(*(dev->pins)), GFP_KERNEL);
if (!dev->pins)
return -ENOMEM;
dev->pins->p = devm_pinctrl_get(dev);
if (IS_ERR(dev->pins->p)) {
dev_dbg(dev, "no pinctrl handle\n");
ret = PTR_ERR(dev->pins->p);
goto cleanup_alloc;
}
dev->pins->default_state = pinctrl_lookup_state(dev->pins->p,
PINCTRL_STATE_DEFAULT);
if (IS_ERR(dev->pins->default_state)) {
dev_dbg(dev, "no default pinctrl state\n");
ret = 0;
goto cleanup_get;
}
dev->pins->init_state = pinctrl_lookup_state(dev->pins->p,
PINCTRL_STATE_INIT);
if (IS_ERR(dev->pins->init_state)) {
/* Not supplying this state is perfectly legal */
dev_dbg(dev, "no init pinctrl state\n");
ret = pinctrl_select_state(dev->pins->p,
dev->pins->default_state);
} else {
ret = pinctrl_select_state(dev->pins->p, dev->pins->init_state);
}
if (ret) {
dev_dbg(dev, "failed to activate initial pinctrl state\n");
goto cleanup_get;
}
#ifdef CONFIG_PM
/*
* If power management is enabled, we also look for the optional
* sleep and idle pin states, with semantics as defined in
* <linux/pinctrl/pinctrl-state.h>
*/
dev->pins->sleep_state = pinctrl_lookup_state(dev->pins->p,
PINCTRL_STATE_SLEEP);
if (IS_ERR(dev->pins->sleep_state))
/* Not supplying this state is perfectly legal */
dev_dbg(dev, "no sleep pinctrl state\n");
dev->pins->idle_state = pinctrl_lookup_state(dev->pins->p,
PINCTRL_STATE_IDLE);
if (IS_ERR(dev->pins->idle_state))
/* Not supplying this state is perfectly legal */
dev_dbg(dev, "no idle pinctrl state\n");
#endif
return 0;
/*
* If no pinctrl handle or default state was found for this device,
* let's explicitly free the pin container in the device, there is
* no point in keeping it around.
*/
cleanup_get:
devm_pinctrl_put(dev->pins->p);
cleanup_alloc:
devm_kfree(dev, dev->pins);
dev->pins = NULL;
/* Return deferrals */
if (ret == -EPROBE_DEFER)
return ret;
/* Return serious errors */
if (ret == -EINVAL)
return ret;
/* We ignore errors like -ENOENT meaning no pinctrl state */
return 0;
}