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gpiolib: check the 'ngpios' property in core gpiolib code

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Several drivers read the 'ngpios' device property on their own, but
since it's defined as a standard GPIO property in the device tree bindings
anyway, it's a good candidate for generalization. If the driver didn't
set its gc->ngpio, try to read the 'ngpios' property from the GPIO
device's firmware node before bailing out.

Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
This commit is contained in:
Bartosz Golaszewski 2021-12-02 14:40:34 +01:00
parent e5ab49cd3d
commit 9dbd1ab205
1 changed files with 21 additions and 0 deletions
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21
drivers/gpio/gpiolib.c
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@ -599,6 +599,7 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
int base = gc->base;
unsigned int i;
int ret = 0;
u32 ngpios;
/*
* First: allocate and populate the internal stat container, and
@ -646,6 +647,26 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
goto err_free_dev_name;
}
/*
* Try the device properties if the driver didn't supply the number
* of GPIO lines.
*/
if (gc->ngpio == 0) {
ret = device_property_read_u32(&gdev->dev, "ngpios", &ngpios);
if (ret == -ENODATA)
/*
* -ENODATA means that there is no property found and
* we want to issue the error message to the user.
* Besides that, we want to return different error code
* to state that supplied value is not valid.
*/
ngpios = 0;
else if (ret)
goto err_free_descs;
gc->ngpio = ngpios;
}
if (gc->ngpio == 0) {
chip_err(gc, "tried to insert a GPIO chip with zero lines\n");
ret = -EINVAL;