From: Brian Masney masneyb@onstation.org
[ Upstream commit 7ed07855773814337b9814f1c3e866df52ebce68 ]
When attempting to setup up a gpio hog, device probing will repeatedly fail with -EPROBE_DEFERED errors. It is 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.
I did not test this change against any hardware supported by this particular driver, however I was able to validate this same fix works for pinctrl-spmi-gpio.c using a LG Nexus 5 (hammerhead) phone.
Signed-off-by: Brian Masney masneyb@onstation.org Reviewed-by: Bjorn Andersson bjorn.andersson@linaro.org Signed-off-by: Linus Walleij linus.walleij@linaro.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/pinctrl/qcom/pinctrl-ssbi-gpio.c | 23 +++++++++++++++++------ 1 file changed, 17 insertions(+), 6 deletions(-)
diff --git a/drivers/pinctrl/qcom/pinctrl-ssbi-gpio.c b/drivers/pinctrl/qcom/pinctrl-ssbi-gpio.c index 0e153bae322ee..6bed433e54205 100644 --- a/drivers/pinctrl/qcom/pinctrl-ssbi-gpio.c +++ b/drivers/pinctrl/qcom/pinctrl-ssbi-gpio.c @@ -762,12 +762,23 @@ static int pm8xxx_gpio_probe(struct platform_device *pdev) return ret; }
- ret = gpiochip_add_pin_range(&pctrl->chip, - dev_name(pctrl->dev), - 0, 0, pctrl->chip.ngpio); - if (ret) { - dev_err(pctrl->dev, "failed to add pin range\n"); - goto unregister_gpiochip; + /* + * 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(pctrl->dev->of_node, "gpio-ranges")) { + ret = gpiochip_add_pin_range(&pctrl->chip, dev_name(pctrl->dev), + 0, 0, pctrl->chip.ngpio); + if (ret) { + dev_err(pctrl->dev, "failed to add pin range\n"); + goto unregister_gpiochip; + } }
platform_set_drvdata(pdev, pctrl);