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 <[email protected]> --- drivers/pinctrl/pinctrl-nomadik.c | 48 ++++++++++++++++++++++++++++++++++++++- 1 file changed, 47 insertions(+), 1 deletion(-) diff --git a/drivers/pinctrl/pinctrl-nomadik.c b/drivers/pinctrl/pinctrl-nomadik.c index 4a1cfdc..ee87e73 100644 --- a/drivers/pinctrl/pinctrl-nomadik.c +++ b/drivers/pinctrl/pinctrl-nomadik.c @@ -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; } -- 1.8.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-gpio" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
