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

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
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
Documentation/pinctrl.txt
View File

@ -79,9 +79,7 @@ int __init foo_probe(void)
{
struct pinctrl_dev *pctl;
pctl = pinctrl_register(&foo_desc, <PARENT>, NULL);
if (!pctl)
pr_err("could not register foo pin driver\n");
return pinctrl_register_and_init(&foo_desc, <PARENT>, NULL, &pctl);
}
To enable the pinctrl subsystem and the subgroups for PINMUX and PINCONF and

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

2
drivers/pinctrl/core.h
View File

@ -37,7 +37,6 @@ struct pinctrl_gpio_range;
* @p: result of pinctrl_get() for this device
* @hog_default: default state for pins hogged by this device
* @hog_sleep: sleep state for pins hogged by this device
* @late_init: delayed work for pin controller to finish registration
* @mutex: mutex taken on each pin controller specific action
* @device_root: debugfs root for this device
*/
@ -60,7 +59,6 @@ struct pinctrl_dev {
struct pinctrl *p;
struct pinctrl_state *hog_default;
struct pinctrl_state *hog_sleep;
struct delayed_work late_init;
struct mutex mutex;
#ifdef CONFIG_DEBUG_FS
struct dentry *device_root;

8
drivers/pinctrl/freescale/pinctrl-imx.c
View File

@ -774,11 +774,11 @@ int imx_pinctrl_probe(struct platform_device *pdev,
ipctl->info = info;
ipctl->dev = info->dev;
platform_set_drvdata(pdev, ipctl);
ipctl->pctl = devm_pinctrl_register(&pdev->dev,
imx_pinctrl_desc, ipctl);
if (IS_ERR(ipctl->pctl)) {
ret = devm_pinctrl_register_and_init(&pdev->dev,
imx_pinctrl_desc, ipctl,
&ipctl->pctl);
if (ret) {
dev_err(&pdev->dev, "could not register IMX pinctrl driver\n");
ret = PTR_ERR(ipctl->pctl);
goto free;
}

5
drivers/pinctrl/pinctrl-single.c
View File

@ -1747,10 +1747,9 @@ static int pcs_probe(struct platform_device *pdev)
if (ret < 0)
goto free;
pcs->pctl = pinctrl_register(&pcs->desc, pcs->dev, pcs);
if (IS_ERR(pcs->pctl)) {
ret = pinctrl_register_and_init(&pcs->desc, pcs->dev, pcs, &pcs->pctl);
if (ret) {
dev_err(pcs->dev, "could not register single pinctrl driver\n");
ret = PTR_ERR(pcs->pctl);
goto free;
}

4
drivers/pinctrl/sh-pfc/pinctrl.c
View File

@ -816,6 +816,6 @@ int sh_pfc_register_pinctrl(struct sh_pfc *pfc)
pmx->pctl_desc.pins = pmx->pins;
pmx->pctl_desc.npins = pfc->info->nr_pins;
pmx->pctl = devm_pinctrl_register(pfc->dev, &pmx->pctl_desc, pmx);
return PTR_ERR_OR_ZERO(pmx->pctl);
return devm_pinctrl_register_and_init(pfc->dev, &pmx->pctl_desc, pmx,
&pmx->pctl);
}

5
drivers/pinctrl/ti/pinctrl-ti-iodelay.c
View File

@ -891,10 +891,9 @@ static int ti_iodelay_probe(struct platform_device *pdev)
iod->desc.name = dev_name(dev);
iod->desc.owner = THIS_MODULE;
iod->pctl = pinctrl_register(&iod->desc, dev, iod);
if (!iod->pctl) {
ret = pinctrl_register_and_init(&iod->desc, dev, iod, &iod->pctl);
if (ret) {
dev_err(dev, "Failed to register pinctrl\n");
ret = -ENODEV;
goto exit_out;
}

15
include/linux/pinctrl/pinctrl.h
View File

@ -141,12 +141,27 @@ struct pinctrl_desc {
};
/* External interface to pin controller */
extern int pinctrl_register_and_init(struct pinctrl_desc *pctldesc,
struct device *dev, void *driver_data,
struct pinctrl_dev **pctldev);
/* Please use pinctrl_register_and_init() instead */
extern struct pinctrl_dev *pinctrl_register(struct pinctrl_desc *pctldesc,
struct device *dev, void *driver_data);
extern void pinctrl_unregister(struct pinctrl_dev *pctldev);
extern int devm_pinctrl_register_and_init(struct device *dev,
struct pinctrl_desc *pctldesc,
void *driver_data,
struct pinctrl_dev **pctldev);
/* Please use devm_pinctrl_register_and_init() instead */
extern struct pinctrl_dev *devm_pinctrl_register(struct device *dev,
struct pinctrl_desc *pctldesc,
void *driver_data);
extern void devm_pinctrl_unregister(struct device *dev,
struct pinctrl_dev *pctldev);