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.brezil...@bootlin.com> Signed-off-by: Janusz Krzysztofik <jmkrzy...@gmail.com> Reviewed-by: Boris Brezillon <boris.brezil...@bootlin.com> --- Changelog v2: fix typo (latar -> later) - thanks Boris and Andy for catching this I'm not sure if adding both Suggested-by: and Reviewed-by: heades both with the same person name is in line with good practices, please remove one if not. Thanks, Janusz drivers/gpio/gpiolib.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index e11a3bb03820..01295c03b315 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -3639,9 +3639,16 @@ 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) { -- 2.16.4
