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    Subject[PATCH 4.14 043/267] pinctrl: qcom: ssbi-gpio: fix gpio-hog related boot issues
    Date
    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);
    --
    2.20.1


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