Hello, On Wed, Jul 04, 2018 at 09:13:42PM +0200, Janusz Krzysztofik wrote: > On Tuesday, July 3, 2018 7:31:41 PM CEST Boris Brezillon wrote: > > Hi Janusz, > > > > On Tue, 3 Jul 2018 19:26:35 +0200 > > > > Janusz Krzysztofik <jmkrzyszt@xxxxxxxxx> wrote: > > > 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. > > > > > > Signed-off-by: Janusz Krzysztofik <jmkrzyszt@xxxxxxxxx> > > > --- > > > If accepted, please add > > > > > > Suggested-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxx> > > > > > > if Boris doesn't mind. > > > > > > 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..15dc77c80328 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 latar and let the interested > > > > ^ later > > > > > + * 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) { > > > > Looks good otherwise. Let's hope we're not breaking implementations > > testing for -ENODEV... > > I've reviewed them all and found two which I think may be affected: > - drivers/mfd/arizona-core.c, > - drivers/i2c/busses/i2c-imx.c. > As far as I can understand the code, both depend on error != -EPROBE_DEFER in > order to continue in degraded mode. I'm adding their maintainers to the loop. TL;DR: Either I don't understand the implication for drivers/i2c/busses/i2c-imx.c or everything is fine. Given that only i2c_imx_init_recovery_info() uses gpio functions I assume you mean: rinfo->sda_gpiod = devm_gpiod_get(&pdev->dev, "sda", GPIOD_IN); rinfo->scl_gpiod = devm_gpiod_get(&pdev->dev, "scl", GPIOD_OUT_HIGH); if (PTR_ERR(rinfo->sda_gpiod) == -EPROBE_DEFER || PTR_ERR(rinfo->scl_gpiod) == -EPROBE_DEFER) { return -EPROBE_DEFER; } else if (IS_ERR(rinfo->sda_gpiod) || IS_ERR(rinfo->scl_gpiod) || IS_ERR(i2c_imx->pinctrl_pins_default) || IS_ERR(i2c_imx->pinctrl_pins_gpio)) { dev_dbg(&pdev->dev, "recovery information incomplete\n"); return 0; } So if a patch changes devm_gpiod_get() to return -EPROBE_DEFER in more cases that doesn't seem to hurt. Moreover TTBOMK this driver should only be used by dt-machines today such that changing gpio* for non-DT users shouldn't affect it. Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ |
