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pinctrl: core: Fix regression caused by delayed work for hogs

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Commit df61b366af26 ("pinctrl: core: Use delayed work for hogs") caused a
regression at least with sh-pfc that is also a GPIO controller as
noted by Geert Uytterhoeven <geert@linux-m68k.org>.

As the original pinctrl_register() has issues calling pin controller
driver functions early before the controller has finished registering,
we can't just revert commit df61b366af26. That would break the drivers
using GENERIC_PINCTRL_GROUPS or GENERIC_PINMUX_FUNCTIONS.

So let's fix the issue with the following steps as a single patch:

1. Revert the late_init parts of commit df61b366af26.

   The late_init clearly won't work and we have to just give up
   on fixing pinctrl_register() for GENERIC_PINCTRL_GROUPS and
   GENERIC_PINMUX_FUNCTIONS.

2. Split pinctrl_register() into two parts

   By splitting pinctrl_register() into pinctrl_init_controller()
   and pinctrl_create_and_start() we have better control over when
   it's safe to call pinctrl_create().

3. Introduce a new pinctrl_register_and_init() function

   As suggested by Linus Walleij <linus.walleij@linaro.org>, we
   can just introduce a new function for the controllers that need
   pinctrl_create() called later.

4. Convert the four known problem cases to use new function

   Let's convert pinctrl-imx, pinctrl-single, sh-pfc and ti-iodelay
   to use the new function to fix the issues. The rest of the drivers
   can be converted later. Let's also update Documentation/pinctrl.txt
   accordingly because of the known issues with pinctrl_register().

Fixes: df61b366af26 ("pinctrl: core: Use delayed work for hogs")
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Gary Bisson <gary.bisson@boundarydevices.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Tony Lindgren
2017-01-11 14:13:34 -08:00
committed by Linus Walleij
parent 56d9e4a760
commit 950b0d91dc
8 changed files with 165 additions and 79 deletions
Download Patch File Download Diff File Expand all files Collapse all files

201
drivers/pinctrl/core.c
View File

@@ -1905,59 +1905,14 @@ static int pinctrl_check_ops(struct pinctrl_dev *pctldev)
}
/**
* pinctrl_late_init() - finish pin controller device registration
* @work: work struct
*/
static void pinctrl_late_init(struct work_struct *work)
{
struct pinctrl_dev *pctldev;
pctldev = container_of(work, struct pinctrl_dev, late_init.work);
/*
* If the pin controller does NOT have hogs, this will report an
* error and we skip over this entire branch. This is why we can
* call this function directly when we do not have hogs on the
* device.
*/
pctldev->p = create_pinctrl(pctldev->dev, pctldev);
if (!IS_ERR(pctldev->p)) {
kref_get(&pctldev->p->users);
pctldev->hog_default =
pinctrl_lookup_state(pctldev->p, PINCTRL_STATE_DEFAULT);
if (IS_ERR(pctldev->hog_default)) {
dev_dbg(pctldev->dev,
"failed to lookup the default state\n");
} else {
if (pinctrl_select_state(pctldev->p,
pctldev->hog_default))
dev_err(pctldev->dev,
"failed to select default state\n");
}
pctldev->hog_sleep =
pinctrl_lookup_state(pctldev->p,
PINCTRL_STATE_SLEEP);
if (IS_ERR(pctldev->hog_sleep))
dev_dbg(pctldev->dev,
"failed to lookup the sleep state\n");
}
mutex_lock(&pinctrldev_list_mutex);
list_add_tail(&pctldev->node, &pinctrldev_list);
mutex_unlock(&pinctrldev_list_mutex);
pinctrl_init_device_debugfs(pctldev);
}
/**
* pinctrl_register() - register a pin controller device
* pinctrl_init_controller() - init a pin controller device
* @pctldesc: descriptor for this pin controller
* @dev: parent device for this pin controller
* @driver_data: private pin controller data for this pin controller
*/
struct pinctrl_dev *pinctrl_register(struct pinctrl_desc *pctldesc,
struct device *dev, void *driver_data)
struct pinctrl_dev *pinctrl_init_controller(struct pinctrl_desc *pctldesc,
struct device *dev,
void *driver_data)
{
struct pinctrl_dev *pctldev;
int ret;
@@ -1983,7 +1938,6 @@ struct pinctrl_dev *pinctrl_register(struct pinctrl_desc *pctldesc,
INIT_RADIX_TREE(&pctldev->pin_function_tree, GFP_KERNEL);
#endif
INIT_LIST_HEAD(&pctldev->gpio_ranges);
INIT_DELAYED_WORK(&pctldev->late_init, pinctrl_late_init);
pctldev->dev = dev;
mutex_init(&pctldev->mutex);
@@ -2018,17 +1972,6 @@ struct pinctrl_dev *pinctrl_register(struct pinctrl_desc *pctldesc,
goto out_err;
}
/*
* If the device has hogs we want the probe() function of the driver
* to complete before we go in and hog them and add the pin controller
* to the list of controllers. If it has no hogs, we can just complete
* the registration immediately.
*/
if (pinctrl_dt_has_hogs(pctldev))
schedule_delayed_work(&pctldev->late_init, 0);
else
pinctrl_late_init(&pctldev->late_init.work);
return pctldev;
out_err:
@@ -2036,8 +1979,107 @@ out_err:
kfree(pctldev);
return ERR_PTR(ret);
}
static int pinctrl_create_and_start(struct pinctrl_dev *pctldev)
{
pctldev->p = create_pinctrl(pctldev->dev, pctldev);
if (!IS_ERR(pctldev->p)) {
kref_get(&pctldev->p->users);
pctldev->hog_default =
pinctrl_lookup_state(pctldev->p, PINCTRL_STATE_DEFAULT);
if (IS_ERR(pctldev->hog_default)) {
dev_dbg(pctldev->dev,
"failed to lookup the default state\n");
} else {
if (pinctrl_select_state(pctldev->p,
pctldev->hog_default))
dev_err(pctldev->dev,
"failed to select default state\n");
}
pctldev->hog_sleep =
pinctrl_lookup_state(pctldev->p,
PINCTRL_STATE_SLEEP);
if (IS_ERR(pctldev->hog_sleep))
dev_dbg(pctldev->dev,
"failed to lookup the sleep state\n");
}
mutex_lock(&pinctrldev_list_mutex);
list_add_tail(&pctldev->node, &pinctrldev_list);
mutex_unlock(&pinctrldev_list_mutex);
pinctrl_init_device_debugfs(pctldev);
return 0;
}
/**
* pinctrl_register() - register a pin controller device
* @pctldesc: descriptor for this pin controller
* @dev: parent device for this pin controller
* @driver_data: private pin controller data for this pin controller
*
* Note that pinctrl_register() is known to have problems as the pin
* controller driver functions are called before the driver has a
* struct pinctrl_dev handle. To avoid issues later on, please use the
* new pinctrl_register_and_init() below instead.
*/
struct pinctrl_dev *pinctrl_register(struct pinctrl_desc *pctldesc,
struct device *dev, void *driver_data)
{
struct pinctrl_dev *pctldev;
int error;
pctldev = pinctrl_init_controller(pctldesc, dev, driver_data);
if (IS_ERR(pctldev))
return pctldev;
error = pinctrl_create_and_start(pctldev);
if (error) {
mutex_destroy(&pctldev->mutex);
kfree(pctldev);
return ERR_PTR(error);
}
return pctldev;
}
EXPORT_SYMBOL_GPL(pinctrl_register);
int pinctrl_register_and_init(struct pinctrl_desc *pctldesc,
struct device *dev, void *driver_data,
struct pinctrl_dev **pctldev)
{
struct pinctrl_dev *p;
int error;
p = pinctrl_init_controller(pctldesc, dev, driver_data);
if (IS_ERR(p))
return PTR_ERR(p);
/*
* We have pinctrl_start() call functions in the pin controller
* driver with create_pinctrl() for at least dt_node_to_map(). So
* let's make sure pctldev is properly initialized for the
* pin controller driver before we do anything.
*/
*pctldev = p;
error = pinctrl_create_and_start(p);
if (error) {
mutex_destroy(&p->mutex);
kfree(p);
*pctldev = NULL;
return error;
}
return 0;
}
EXPORT_SYMBOL_GPL(pinctrl_register_and_init);
/**
* pinctrl_unregister() - unregister pinmux
* @pctldev: pin controller to unregister
@@ -2052,7 +2094,6 @@ void pinctrl_unregister(struct pinctrl_dev *pctldev)
if (pctldev == NULL)
return;
cancel_delayed_work_sync(&pctldev->late_init);
mutex_lock(&pctldev->mutex);
pinctrl_remove_device_debugfs(pctldev);
mutex_unlock(&pctldev->mutex);
@@ -2133,6 +2174,42 @@ struct pinctrl_dev *devm_pinctrl_register(struct device *dev,
}
EXPORT_SYMBOL_GPL(devm_pinctrl_register);
/**
* devm_pinctrl_register_and_init() - Resource managed pinctrl register and init
* @dev: parent device for this pin controller
* @pctldesc: descriptor for this pin controller
* @driver_data: private pin controller data for this pin controller
*
* Returns an error pointer if pincontrol register failed. Otherwise
* it returns valid pinctrl handle.
*
* The pinctrl device will be automatically released when the device is unbound.
*/
int devm_pinctrl_register_and_init(struct device *dev,
struct pinctrl_desc *pctldesc,
void *driver_data,
struct pinctrl_dev **pctldev)
{
struct pinctrl_dev **ptr;
int error;
ptr = devres_alloc(devm_pinctrl_dev_release, sizeof(*ptr), GFP_KERNEL);
if (!ptr)
return -ENOMEM;
error = pinctrl_register_and_init(pctldesc, dev, driver_data, pctldev);
if (error) {
devres_free(ptr);
return error;
}
*ptr = *pctldev;
devres_add(dev, ptr);
return 0;
}
EXPORT_SYMBOL_GPL(devm_pinctrl_register_and_init);
/**
* devm_pinctrl_unregister() - Resource managed version of pinctrl_unregister().
* @dev: device for which which resource was allocated