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gpiolib: Defer on non-DT find_chip_by_name() failure 

Avoid replication of error code conversion in non-DT GPIO consumers'
code by returning -EPROBE_DEFER from gpiod_find() in case a chip
identified by its label in a registered lookup table is not ready.

See https://lkml.org/lkml/2018/5/30/176 for example case.

Suggested-by: Boris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: Janusz Krzysztofik <jmkrzyszt@gmail.com>
Reviewed-by: Boris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Janusz Krzysztofik 2018-07-04 00:18:19 +02:00 committed by Linus Walleij
parent 36b312792b
commit 8853daf3b4
1 changed files with 10 additions and 3 deletions
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13
drivers/gpio/gpiolib.c
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@ -3656,9 +3656,16 @@ static struct gpio_desc *gpiod_find(struct device *dev, const char *con_id,
chip = find_chip_by_name(p->chip_label);
if (!chip) {
dev_err(dev, "cannot find GPIO chip %s\n",
p->chip_label);
return ERR_PTR(-ENODEV);
/*
* As the lookup table indicates a chip with
* p->chip_label should exist, assume it may
* still appear later and let the interested
* consumer be probed again or let the Deferred
* Probe infrastructure handle the error.
*/
dev_warn(dev, "cannot find GPIO chip %s, deferring\n",
p->chip_label);
return ERR_PTR(-EPROBE_DEFER);
}
if (chip->ngpio <= p->chip_hwnum) {