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Date: Mon, 17 Feb 2020 20:24:04 +0900 From: Chanwoo Choi <cw00.choi@...sung.com> To: "H. Nikolaus Schaller" <hns@...delico.com> Cc: MyungJoo Ham <myungjoo.ham@...sung.com>, linux-kernel@...r.kernel.org, letux-kernel@...nphoenux.org, kernel@...a-handheld.com, linux-omap@...r.kernel.org Subject: Re: [PATCH] extcon: palmas: hide error messages if gpio returns -EPROBE_DEFER Hi, On 2/17/20 8:07 PM, H. Nikolaus Schaller wrote: > Hi Chanwoo Choi, > >> Am 17.02.2020 um 11:15 schrieb Chanwoo Choi <cw00.choi@...sung.com>: >> >> Hi, >> >> On 2/17/20 5:55 PM, H. Nikolaus Schaller wrote: >>> If the gpios are probed after this driver (e.g. if they >>> come from an i2c expander) there is no need to print an >>> error message. >>> >>> Signed-off-by: H. Nikolaus Schaller <hns@...delico.com> >>> --- >>> drivers/extcon/extcon-palmas.c | 6 ++++-- >>> 1 file changed, 4 insertions(+), 2 deletions(-) >>> >>> diff --git a/drivers/extcon/extcon-palmas.c b/drivers/extcon/extcon-palmas.c >>> index edc5016f46f1..9c6254c0531c 100644 >>> --- a/drivers/extcon/extcon-palmas.c >>> +++ b/drivers/extcon/extcon-palmas.c >>> @@ -206,14 +206,16 @@ static int palmas_usb_probe(struct platform_device *pdev) >>> palmas_usb->id_gpiod = devm_gpiod_get_optional(&pdev->dev, "id", >>> GPIOD_IN); >>> if (IS_ERR(palmas_usb->id_gpiod)) { >>> - dev_err(&pdev->dev, "failed to get id gpio\n"); >>> + if (PTR_ERR(palmas_usb->id_gpiod) != -EPROBE_DEFER) >>> + dev_err(&pdev->dev, "failed to get id gpio\n"); >>> return PTR_ERR(palmas_usb->id_gpiod); >>> } How about editing it ? as following: because following suggestion reduces the one checking behavior when return value is -EPROBE_DEFER. if (PTR_ERR(palmas_usb->id_gpiod) == -EPROBE_DEFER) { return -EPROBE_DEFER; } else if (IS_ERR(palmas_usb->id_gpiod)) { dev_err(&pdev->dev, "failed to get id gpio\n"); return PTR_ERR(palmas_usb->id_gpiod); } >>> >>> palmas_usb->vbus_gpiod = devm_gpiod_get_optional(&pdev->dev, "vbus", >>> GPIOD_IN); >>> if (IS_ERR(palmas_usb->vbus_gpiod)) { >>> - dev_err(&pdev->dev, "failed to get vbus gpio\n"); >>> + if (PTR_ERR(palmas_usb->vbus_gpiod) != -EPROBE_DEFER) >>> + dev_err(&pdev->dev, "failed to get vbus gpio\n"); ditto. >>> return PTR_ERR(palmas_usb->vbus_gpiod); >>> } >>> >>> >> >> Usually, gpio driver like pinctrl is very early probed >> because almost device drivers should use gpio. >> So, I have not any experience about this situation. >> Do you meet this situation on any h/w board? > > Yes, I have experienced that sometimes on omap5+palmas based boards. > > It seems to be this: > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm/boot/dts/omap5-board-common.dtsi?h=v5.6-rc2#n384 > > The extcon_usb3 can potentially match this extcon-palmas driver at > a moment where the palmas_gpio it is referring to has not yet been > successfully probed. Then the palmas_gpio would return -EPROBE_DEFER. > > AFAIK there is no guarantee for a specific sequence of drivers > being probed and it is pure luck that in most cases the gpios > are already probed. Thanks for explaining the example. -- Best Regards, Chanwoo Choi Samsung Electronics
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