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pinctrl: qcom: spmi-gpio: fix gpio-hog related boot issues 

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 a86caa9ba5 ("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>
This commit is contained in:
Brian Masney 2018-10-31 20:11:47 -04:00 committed by Linus Walleij
parent 78bf386daf
commit 149a960472
1 changed files with 17 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
drivers/pinctrl/qcom/pinctrl-spmi-gpio.c
View File

@ -1028,10 +1028,23 @@ static int pmic_gpio_probe(struct platform_device *pdev)
return ret;
}
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;