From: Brian Masney masneyb@onstation.org
[ Upstream commit 149a96047237574b756d872007c006acd0cc6687 ]
When attempting to setup up a gpio hog, device probing would repeatedly fail with -EPROBE_DEFERED errors. It was caused by a circular dependency between the gpio and pinctrl frameworks. If the gpio-ranges property is present in device tree, then the gpio framework will handle the gpio pin registration and eliminate the circular dependency.
See Christian Lamparter's commit a86caa9ba5d7 ("pinctrl: msm: fix gpio-hog related boot issues") for a detailed commit message that explains the issue in much more detail. The code comment in this commit came from Christian's commit.
Signed-off-by: Brian Masney masneyb@onstation.org Signed-off-by: Linus Walleij linus.walleij@linaro.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/pinctrl/qcom/pinctrl-spmi-gpio.c | 21 +++++++++++++++++---- 1 file changed, 17 insertions(+), 4 deletions(-)
diff --git a/drivers/pinctrl/qcom/pinctrl-spmi-gpio.c b/drivers/pinctrl/qcom/pinctrl-spmi-gpio.c index 4ea810cafaac6..913b2604d3454 100644 --- a/drivers/pinctrl/qcom/pinctrl-spmi-gpio.c +++ b/drivers/pinctrl/qcom/pinctrl-spmi-gpio.c @@ -793,10 +793,23 @@ static int pmic_gpio_probe(struct platform_device *pdev) goto err_chip; }
- ret = gpiochip_add_pin_range(&state->chip, dev_name(dev), 0, 0, npins); - if (ret) { - dev_err(dev, "failed to add pin range\n"); - goto err_range; + /* + * For DeviceTree-supported systems, the gpio core checks the + * pinctrl's device node for the "gpio-ranges" property. + * If it is present, it takes care of adding the pin ranges + * for the driver. In this case the driver can skip ahead. + * + * In order to remain compatible with older, existing DeviceTree + * files which don't set the "gpio-ranges" property or systems that + * utilize ACPI the driver has to call gpiochip_add_pin_range(). + */ + if (!of_property_read_bool(dev->of_node, "gpio-ranges")) { + ret = gpiochip_add_pin_range(&state->chip, dev_name(dev), 0, 0, + npins); + if (ret) { + dev_err(dev, "failed to add pin range\n"); + goto err_range; + } }
return 0;