Hi Dmitry, Mattijs Korpershoek <mkorpershoek@xxxxxxxxxxxx> writes: > Hi Dmitry, > > Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx> writes: > >> Hi Mattijs, >> >> On Wed, Apr 28, 2021 at 06:42:13PM +0200, Mattijs Korpershoek wrote: >>> mtk-pmic-keys being a child device of mt6397, it will always get probed >>> when mt6397_probe() is called. >>> >>> This also happens when we have no device tree node matching >>> mediatek,mt6397-keys. >> >> It sounds for me that creating a platform device instance in case where >> we know need OF node, but do not have one, is wasteful. Can >> mt6397-core.c and/or MFD core be adjusted to not do that. > > You are right. Maybe I can fix MFD core instead. I will look into it. > > Thanks for your review. >> >>> >>> In that case, the mfd core warns us: >>> >>> [ 0.352175] mtk-pmic-keys: Failed to locate of_node [id: -1] >>> >>> Check return value from call to of_match_device() >>> in order to prevent a NULL pointer dereference. >>> >>> In case of NULL print error message and return -ENODEV >>> >>> Signed-off-by: Mattijs Korpershoek <mkorpershoek@xxxxxxxxxxxx> >>> --- >>> drivers/input/keyboard/mtk-pmic-keys.c | 3 +++ >>> 1 file changed, 3 insertions(+) >>> >>> diff --git a/drivers/input/keyboard/mtk-pmic-keys.c b/drivers/input/keyboard/mtk-pmic-keys.c >>> index 62391d6c7da6..12c449eed026 100644 >>> --- a/drivers/input/keyboard/mtk-pmic-keys.c >>> +++ b/drivers/input/keyboard/mtk-pmic-keys.c >>> @@ -247,6 +247,9 @@ static int mtk_pmic_keys_probe(struct platform_device *pdev) >>> const struct of_device_id *of_id = >>> of_match_device(of_mtk_pmic_keys_match_tbl, &pdev->dev); >>> >>> + if (!of_id) >>> + return -ENODEV; >>> + >> >> So if we make MFD/6396 core smarter we would not be needing this. I >> guess there is still a possibility of someone stuffing "mtk-pmic-keys" >> into "driver_override" attribute of a random platform device but I >> wonder if we really need to take care of such scenarios... It turns out it was possible to make 6397-core smarter. I've submitted [1] to replace this patch. Thanks again for your suggestion. Please let me know if I should add your Suggested-by: in [1]. [1] https://patchwork.kernel.org/project/linux-mediatek/patch/20210429143811.2030717-1-mkorpershoek@xxxxxxxxxxxx/ instead >> >>> keys = devm_kzalloc(&pdev->dev, sizeof(*keys), GFP_KERNEL); >>> if (!keys) >>> return -ENOMEM; >>> -- >>> 2.27.0 >>> >> >> Thanks. >> >> -- >> Dmitry
