[PATCH] pinctrl: Add device link between pin controller and GPIO

[PATCH] pinctrl: Add device link between pin controller and GPIO

[Thierry Reding]

From: Thierry Reding <treding@nvidia.com>

When a GPIO controller registers a pin range with a pin controller,
establish a device link between them in order to keep track of the
dependency, which will help keep the right suspend/resume ordering.

Signed-off-by: Thierry Reding <treding@nvidia.com>
---
 drivers/pinctrl/core.c | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/drivers/pinctrl/core.c b/drivers/pinctrl/core.c
index b70df27874d1..5079e8a5de61 100644
--- a/drivers/pinctrl/core.c
+++ b/drivers/pinctrl/core.c
@@ -404,6 +404,17 @@ void pinctrl_add_gpio_range(struct pinctrl_dev *pctldev,
 	mutex_lock(&pctldev->mutex);
 	list_add_tail(&range->node, &pctldev->gpio_ranges);
 	mutex_unlock(&pctldev->mutex);
+
+	if (range->gc) {
+		struct device_link *link;
+
+		link = device_link_add(range->gc->parent, pctldev->dev,
+				       DL_FLAG_AUTOREMOVE_CONSUMER);
+		if (!link)
+			dev_err(pctldev->dev,
+				"failed to add device link to %s\n",
+				dev_name(range->gc->parent));
+	}
 }
 EXPORT_SYMBOL_GPL(pinctrl_add_gpio_range);
 
@@ -2136,8 +2147,12 @@ void pinctrl_unregister(struct pinctrl_dev *pctldev)
 	pinctrl_free_pindescs(pctldev, pctldev->desc->pins,
 			      pctldev->desc->npins);
 	/* remove gpio ranges map */
-	list_for_each_entry_safe(range, n, &pctldev->gpio_ranges, node)
+	list_for_each_entry_safe(range, n, &pctldev->gpio_ranges, node) {
+		if (range->gc)
+			device_link_remove(range->gc->parent, pctldev->dev);
+
 		list_del(&range->node);
+	}
 
 	mutex_unlock(&pctldev->mutex);
 	mutex_destroy(&pctldev->mutex);
-- 
2.21.0

Re: [PATCH] pinctrl: Add device link between pin controller and GPIO

[Linus Walleij]

On Fri, Jun 21, 2019 at 5:24 PM Thierry Reding <thierry.reding@gmail.com> wrote:

> From: Thierry Reding <treding@nvidia.com>
>
> When a GPIO controller registers a pin range with a pin controller,
> establish a device link between them in order to keep track of the
> dependency, which will help keep the right suspend/resume ordering.
>
> Signed-off-by: Thierry Reding <treding@nvidia.com>

This make sense.

> +               link = device_link_add(range->gc->parent, pctldev->dev,
> +                                      DL_FLAG_AUTOREMOVE_CONSUMER);

What about parentless GPIO chips now again?
The parent field is optional, sad to say (yes I wish I could just
fix it all).

> +                       device_link_remove(range->gc->parent, pctldev->dev);

And here again.

Yours,
Linus Walleij