@@ -1010,6 +1010,31 @@ static int nmk_gpio_init_irq(struct nmk_gpio_chip *nmk_chip)
/* I/O Functions */
+struct nmk_gpio_req {
+ struct list_head node;
+ int gpio;
+};
+
+static LIST_HEAD(nmk_queued_gpio_requests);
+
+static void nmk_pinctrl_process_queued_gpio_requests(void)
+{
+ struct list_head *node, *tmp;
+
+ list_for_each_safe(node, tmp, &nmk_queued_gpio_requests) {
+ struct nmk_gpio_req *req =
+ list_entry(node, struct nmk_gpio_req, node);
+ int ret;
+ ret = pinctrl_request_gpio(req->gpio);
+ if (ret)
+ pr_err("failed to request queued GPIO %d\n", req->gpio);
+ else
+ pr_info("requested queued GPIO %d\n", req->gpio);
+ list_del(node);
+ kfree(req);
+ }
+}
+
static int nmk_gpio_request(struct gpio_chip *chip, unsigned offset)
{
/*
@@ -1017,8 +1042,28 @@ static int nmk_gpio_request(struct gpio_chip *chip, unsigned offset)
* parameter does not matter for this controller.
*/
int gpio = chip->base + offset;
+ int ret;
+
+ ret = pinctrl_request_gpio(gpio);
+ if (ret == -EPROBE_DEFER) {
+ /*
+ * This may happen during system startup: we request a GPIO
+ * for being used for IRQ when registering the GPIO controller
+ * for example, but the pin controller is not yet online.
+ * Store the request on a list to be done when the
+ * pin controller comes online. In our driver the GPIO
+ * blocks must always probe before the pin controller.
+ */
+ struct nmk_gpio_req *req = kzalloc(sizeof(struct nmk_gpio_req), GFP_KERNEL);
- return pinctrl_request_gpio(gpio);
+ if (!req)
+ return -ENOMEM;
+ req->gpio = gpio;
+ list_add_tail(&req->node, &nmk_queued_gpio_requests);
+ pr_info("queueing pinctrl_request_gpio(%d)\n", req->gpio);
+ ret = 0;
+ }
+ return ret;
}
static void nmk_gpio_free(struct gpio_chip *chip, unsigned offset)
@@ -2224,6 +2269,7 @@ static int nmk_pinctrl_probe(struct platform_device *pdev)
platform_set_drvdata(pdev, npct);
dev_info(&pdev->dev, "initialized Nomadik pin control driver\n");
+ nmk_pinctrl_process_queued_gpio_requests();
return 0;
}
Instead of deferring if pinctrl_request_gpio() returns -EPROBE_DEFER, queue the GPIO number and request it later, when the pinctrl part of the driver probes. This is because we will otherwise have a circular dependency between the GPIO and pinctrl parts of the driver: the new auto-reservation of IRQ pins from the DT code will attempt to request a GPIO line as soon as the gpiochip is added, but this calls pinctrl_request_gpio() which count on the pinctrl backend being present, and the pinctrl backend will not probe until all the GPIO blocks have probed. So we get locked up in a circular loop unless we do something like this. Signed-off-by: Linus Walleij <linus.walleij@linaro.org> --- drivers/pinctrl/pinctrl-nomadik.c | 48 ++++++++++++++++++++++++++++++++++++++- 1 file changed, 47 insertions(+), 1 deletion(-)