pinctrl: make pinctrl_register() return proper error code

Currently, pinctrl_register() just returns NULL on error, so the
callers can not know the exact reason of the failure.

Some of the pinctrl drivers return -EINVAL, some -ENODEV, and some
-ENOMEM on error of pinctrl_register(), although the error code
might be different from the real cause of the error.

This commit reworks pinctrl_register() to return the appropriate
error code and modifies all of the pinctrl drivers to use IS_ERR()
for the error checking and PTR_ERR() for getting the error code.

Signed-off-by: Masahiro Yamada <[e-mail]>
Acked-by: Patrice Chotard <[e-mail]>
Acked-by: Thierry Reding <[e-mail]>
Acked-by: Heiko Stuebner <[e-mail]>
Tested-by: Mika Westerberg <[e-mail]>
Acked-by: Mika Westerberg <[e-mail]>
Acked-by: Lee Jones <[e-mail]>
Acked-by: Sören Brinkmann <[e-mail]>
Acked-by: Laurent Pinchart <[e-mail]>
Acked-by: Ray Jui <[e-mail]>
Acked-by: Antoine Tenart <[e-mail]>
Acked-by: Hongzhou Yang <[e-mail]>
Acked-by: Wei Chen <[e-mail]>
Signed-off-by: Linus Walleij <[e-mail]>

drivers/pinctrl/bcm/pinctrl-bcm281xx.c

···
 	pctl = pinctrl_register(&bcm281xx_pinctrl_desc,
 				&pdev->dev,
 				pdata);
-	if (!pctl) {
+	if (IS_ERR(pctl)) {
 		dev_err(&pdev->dev, "Failed to register pinctrl\n");
-		return -ENODEV;
+		return PTR_ERR(pctl);
 	}
 
 	platform_set_drvdata(pdev, pdata);

drivers/pinctrl/bcm/pinctrl-bcm2835.c

···
 	}
 
 	pc->pctl_dev = pinctrl_register(&bcm2835_pinctrl_desc, dev, pc);
-	if (!pc->pctl_dev) {
+	if (IS_ERR(pc->pctl_dev)) {
 		gpiochip_remove(&pc->gpio_chip);
-		return -EINVAL;
+		return PTR_ERR(pc->pctl_dev);
 	}
 
 	pc->gpio_range = bcm2835_pinctrl_gpio_range;

drivers/pinctrl/bcm/pinctrl-cygnus-gpio.c

···
 	pctldesc->confops = &cygnus_pconf_ops;
 
 	chip->pctl = pinctrl_register(pctldesc, chip->dev, chip);
-	if (!chip->pctl) {
+	if (IS_ERR(chip->pctl)) {
 		dev_err(chip->dev, "unable to register pinctrl device\n");
-		return -EINVAL;
+		return PTR_ERR(chip->pctl);
 	}
 
 	return 0;

drivers/pinctrl/bcm/pinctrl-cygnus-mux.c

···
 
 	pinctrl->pctl = pinctrl_register(&cygnus_pinctrl_desc, &pdev->dev,
 			pinctrl);
-	if (!pinctrl->pctl) {
+	if (IS_ERR(pinctrl->pctl)) {
 		dev_err(&pdev->dev, "unable to register Cygnus IOMUX pinctrl\n");
-		return -EINVAL;
+		return PTR_ERR(pinctrl->pctl);
 	}
 
 	return 0;

drivers/pinctrl/berlin/berlin.c

···
 	}
 
 	pctrl->pctrl_dev = pinctrl_register(&berlin_pctrl_desc, dev, pctrl);
-	if (!pctrl->pctrl_dev) {
+	if (IS_ERR(pctrl->pctrl_dev)) {
 		dev_err(dev, "failed to register pinctrl driver\n");
-		return -EINVAL;
+		return PTR_ERR(pctrl->pctrl_dev);
 	}
 
 	return 0;

drivers/pinctrl/core.c

···
 	int ret;
 
 	if (!pctldesc)
-		return NULL;
+		return ERR_PTR(-EINVAL);
 	if (!pctldesc->name)
-		return NULL;
+		return ERR_PTR(-EINVAL);
 
 	pctldev = kzalloc(sizeof(*pctldev), GFP_KERNEL);
 	if (pctldev == NULL) {
 		dev_err(dev, "failed to alloc struct pinctrl_dev\n");
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 	}
 
 	/* Initialize pin control device struct */
···
 	mutex_init(&pctldev->mutex);
 
 	/* check core ops for sanity */
-	if (pinctrl_check_ops(pctldev)) {
+	ret = pinctrl_check_ops(pctldev);
+	if (ret) {
 		dev_err(dev, "pinctrl ops lacks necessary functions\n");
 		goto out_err;
 	}
 
 	/* If we're implementing pinmuxing, check the ops for sanity */
 	if (pctldesc->pmxops) {
-		if (pinmux_check_ops(pctldev))
+		ret = pinmux_check_ops(pctldev);
+		if (ret)
 			goto out_err;
 	}
 
 	/* If we're implementing pinconfig, check the ops for sanity */
 	if (pctldesc->confops) {
-		if (pinconf_check_ops(pctldev))
+		ret = pinconf_check_ops(pctldev);
+		if (ret)
 			goto out_err;
 	}
 
···
 out_err:
 	mutex_destroy(&pctldev->mutex);
 	kfree(pctldev);
-	return NULL;
+	return ERR_PTR(ret);
 }
 EXPORT_SYMBOL_GPL(pinctrl_register);
 

drivers/pinctrl/freescale/pinctrl-imx.c

···
 	ipctl->dev = info->dev;
 	platform_set_drvdata(pdev, ipctl);
 	ipctl->pctl = pinctrl_register(&imx_pinctrl_desc, &pdev->dev, ipctl);
-	if (!ipctl->pctl) {
+	if (IS_ERR(ipctl->pctl)) {
 		dev_err(&pdev->dev, "could not register IMX pinctrl driver\n");
-		return -EINVAL;
+		return PTR_ERR(ipctl->pctl);
 	}
 
 	dev_info(&pdev->dev, "initialized IMX pinctrl driver\n");

drivers/pinctrl/freescale/pinctrl-imx1-core.c

···
 	ipctl->dev = info->dev;
 	platform_set_drvdata(pdev, ipctl);
 	ipctl->pctl = pinctrl_register(pctl_desc, &pdev->dev, ipctl);
-	if (!ipctl->pctl) {
+	if (IS_ERR(ipctl->pctl)) {
 		dev_err(&pdev->dev, "could not register IMX pinctrl driver\n");
-		return -EINVAL;
+		return PTR_ERR(ipctl->pctl);
 	}
 
 	ret = of_platform_populate(pdev->dev.of_node, NULL, NULL, &pdev->dev);

drivers/pinctrl/freescale/pinctrl-mxs.c

···
 	}
 
 	d->pctl = pinctrl_register(&mxs_pinctrl_desc, &pdev->dev, d);
-	if (!d->pctl) {
+	if (IS_ERR(d->pctl)) {
 		dev_err(&pdev->dev, "Couldn't register MXS pinctrl driver\n");
-		ret = -EINVAL;
+		ret = PTR_ERR(d->pctl);
 		goto err;
 	}
 

drivers/pinctrl/intel/pinctrl-cherryview.c

···
 	pctrl->pctldesc.npins = pctrl->community->npins;
 
 	pctrl->pctldev = pinctrl_register(&pctrl->pctldesc, &pdev->dev, pctrl);
-	if (!pctrl->pctldev) {
+	if (IS_ERR(pctrl->pctldev)) {
 		dev_err(&pdev->dev, "failed to register pinctrl driver\n");
-		return -ENODEV;
+		return PTR_ERR(pctrl->pctldev);
 	}
 
 	ret = chv_gpio_probe(pctrl, irq);

drivers/pinctrl/intel/pinctrl-intel.c

···
 	pctrl->pctldesc.npins = pctrl->soc->npins;
 
 	pctrl->pctldev = pinctrl_register(&pctrl->pctldesc, &pdev->dev, pctrl);
-	if (!pctrl->pctldev) {
+	if (IS_ERR(pctrl->pctldev)) {
 		dev_err(&pdev->dev, "failed to register pinctrl driver\n");
-		return -ENODEV;
+		return PTR_ERR(pctrl->pctldev);
 	}
 
 	ret = intel_gpio_probe(pctrl, irq);

drivers/pinctrl/mediatek/pinctrl-mtk-common.c

···
 	mtk_pctrl_desc.npins = pctl->devdata->npins;
 	pctl->dev = &pdev->dev;
 	pctl->pctl_dev = pinctrl_register(&mtk_pctrl_desc, &pdev->dev, pctl);
-	if (!pctl->pctl_dev) {
+	if (IS_ERR(pctl->pctl_dev)) {
 		dev_err(&pdev->dev, "couldn't register pinctrl driver\n");
-		return -EINVAL;
+		return PTR_ERR(pctl->pctl_dev);
 	}
 
 	pctl->chip = devm_kzalloc(&pdev->dev, sizeof(*pctl->chip), GFP_KERNEL);

drivers/pinctrl/meson/pinctrl-meson.c

···
 	pc->desc.npins		= pc->data->num_pins;
 
 	pc->pcdev = pinctrl_register(&pc->desc, pc->dev, pc);
-	if (!pc->pcdev) {
+	if (IS_ERR(pc->pcdev)) {
 		dev_err(pc->dev, "can't register pinctrl device");
-		return -EINVAL;
+		return PTR_ERR(pc->pcdev);
 	}
 
 	ret = meson_gpiolib_register(pc);

drivers/pinctrl/mvebu/pinctrl-mvebu.c

···
 	}
 
 	pctl->pctldev = pinctrl_register(&pctl->desc, &pdev->dev, pctl);
-	if (!pctl->pctldev) {
+	if (IS_ERR(pctl->pctldev)) {
 		dev_err(&pdev->dev, "unable to register pinctrl driver\n");
-		return -EINVAL;
+		return PTR_ERR(pctl->pctldev);
 	}
 
 	dev_info(&pdev->dev, "registered pinctrl driver\n");

drivers/pinctrl/nomadik/pinctrl-abx500.c

···
 	abx500_pinctrl_desc.pins = pct->soc->pins;
 	abx500_pinctrl_desc.npins = pct->soc->npins;
 	pct->pctldev = pinctrl_register(&abx500_pinctrl_desc, &pdev->dev, pct);
-	if (!pct->pctldev) {
+	if (IS_ERR(pct->pctldev)) {
 		dev_err(&pdev->dev,
 			"could not register abx500 pinctrl driver\n");
-		ret = -EINVAL;
+		ret = PTR_ERR(pct->pctldev);
 		goto out_rem_chip;
 	}
 	dev_info(&pdev->dev, "registered pin controller\n");

drivers/pinctrl/nomadik/pinctrl-nomadik.c

···
 	npct->dev = &pdev->dev;
 
 	npct->pctl = pinctrl_register(&nmk_pinctrl_desc, &pdev->dev, npct);
-	if (!npct->pctl) {
+	if (IS_ERR(npct->pctl)) {
 		dev_err(&pdev->dev, "could not register Nomadik pinctrl driver\n");
-		return -EINVAL;
+		return PTR_ERR(npct->pctl);
 	}
 
 	/* We will handle a range of GPIO pins */

drivers/pinctrl/pinctrl-adi2.c

···
 
 	/* Now register the pin controller and all pins it handles */
 	pinctrl->pctl = pinctrl_register(&adi_pinmux_desc, &pdev->dev, pinctrl);
-	if (!pinctrl->pctl) {
+	if (IS_ERR(pinctrl->pctl)) {
 		dev_err(&pdev->dev, "could not register pinctrl ADI2 driver\n");
-		return -EINVAL;
+		return PTR_ERR(pinctrl->pctl);
 	}
 
 	platform_set_drvdata(pdev, pinctrl);

drivers/pinctrl/pinctrl-amd.c

···
 	amd_pinctrl_desc.name = dev_name(&pdev->dev);
 	gpio_dev->pctrl = pinctrl_register(&amd_pinctrl_desc,
 					&pdev->dev, gpio_dev);
-	if (!gpio_dev->pctrl) {
+	if (IS_ERR(gpio_dev->pctrl)) {
 		dev_err(&pdev->dev, "Couldn't register pinctrl driver\n");
-		return -ENODEV;
+		return PTR_ERR(gpio_dev->pctrl);
 	}
 
 	ret = gpiochip_add(&gpio_dev->gc);

drivers/pinctrl/pinctrl-as3722.c

···
 	as3722_pinctrl_desc.npins = ARRAY_SIZE(as3722_pins_desc);
 	as_pci->pctl = pinctrl_register(&as3722_pinctrl_desc,
 					&pdev->dev, as_pci);
-	if (!as_pci->pctl) {
+	if (IS_ERR(as_pci->pctl)) {
 		dev_err(&pdev->dev, "Couldn't register pinctrl driver\n");
-		return -EINVAL;
+		return PTR_ERR(as_pci->pctl);
 	}
 
 	as_pci->gpio_chip = as3722_gpio_chip;

drivers/pinctrl/pinctrl-at91.c

···
 	platform_set_drvdata(pdev, info);
 	info->pctl = pinctrl_register(&at91_pinctrl_desc, &pdev->dev, info);
 
-	if (!info->pctl) {
+	if (IS_ERR(info->pctl)) {
 		dev_err(&pdev->dev, "could not register AT91 pinctrl driver\n");
-		return -EINVAL;
+		return PTR_ERR(info->pctl);
 	}
 
 	/* We will handle a range of GPIO pins */

drivers/pinctrl/pinctrl-lantiq.c

···
 	info->dev = &pdev->dev;
 
 	info->pctrl = pinctrl_register(desc, &pdev->dev, info);
-	if (!info->pctrl) {
+	if (IS_ERR(info->pctrl)) {
 		dev_err(&pdev->dev, "failed to register LTQ pinmux driver\n");
-		return -EINVAL;
+		return PTR_ERR(info->pctrl);
 	}
 	platform_set_drvdata(pdev, info);
 	return 0;

drivers/pinctrl/pinctrl-lpc18xx.c

···
 	platform_set_drvdata(pdev, scu);
 
 	scu->pctl = pinctrl_register(&lpc18xx_scu_desc, &pdev->dev, scu);
-	if (!scu->pctl) {
+	if (IS_ERR(scu->pctl)) {
 		dev_err(&pdev->dev, "Could not register pinctrl driver\n");
 		clk_disable_unprepare(scu->clk);
-		return -EINVAL;
+		return PTR_ERR(scu->pctl);
 	}
 
 	return 0;

drivers/pinctrl/pinctrl-palmas.c

···
 	palmas_pinctrl_desc.pins = palmas_pins_desc;
 	palmas_pinctrl_desc.npins = ARRAY_SIZE(palmas_pins_desc);
 	pci->pctl = pinctrl_register(&palmas_pinctrl_desc, &pdev->dev, pci);
-	if (!pci->pctl) {
+	if (IS_ERR(pci->pctl)) {
 		dev_err(&pdev->dev, "Couldn't register pinctrl driver\n");
-		return -ENODEV;
+		return PTR_ERR(pci->pctl);
 	}
 	return 0;
 }

drivers/pinctrl/pinctrl-pistachio.c

···
 
 	pctl->pctldev = pinctrl_register(&pistachio_pinctrl_desc, &pdev->dev,
 					 pctl);
-	if (!pctl->pctldev) {
+	if (IS_ERR(pctl->pctldev)) {
 		dev_err(&pdev->dev, "Failed to register pinctrl device\n");
-		return -EINVAL;
+		return PTR_ERR(pctl->pctldev);
 	}
 
 	ret = pistachio_gpio_register(pctl);

drivers/pinctrl/pinctrl-rockchip.c

···
 		return ret;
 
 	info->pctl_dev = pinctrl_register(ctrldesc, &pdev->dev, info);
-	if (!info->pctl_dev) {
+	if (IS_ERR(info->pctl_dev)) {
 		dev_err(&pdev->dev, "could not register pinctrl driver\n");
-		return -EINVAL;
+		return PTR_ERR(info->pctl_dev);
 	}
 
 	for (bank = 0; bank < info->ctrl->nr_banks; ++bank) {

drivers/pinctrl/pinctrl-single.c

···
 		goto free;
 
 	pcs->pctl = pinctrl_register(&pcs->desc, pcs->dev, pcs);
-	if (!pcs->pctl) {
+	if (IS_ERR(pcs->pctl)) {
 		dev_err(pcs->dev, "could not register single pinctrl driver\n");
-		ret = -EINVAL;
+		ret = PTR_ERR(pcs->pctl);
 		goto free;
 	}
 

drivers/pinctrl/pinctrl-st.c

···
 	pctl_desc->name		= dev_name(&pdev->dev);
 
 	info->pctl = pinctrl_register(pctl_desc, &pdev->dev, info);
-	if (!info->pctl) {
+	if (IS_ERR(info->pctl)) {
 		dev_err(&pdev->dev, "Failed pinctrl registration\n");
-		return -EINVAL;
+		return PTR_ERR(info->pctl);
 	}
 
 	for (i = 0; i < info->nbanks; i++)

drivers/pinctrl/pinctrl-tb10x.c

···
 	}
 
 	state->pctl = pinctrl_register(&tb10x_pindesc, dev, state);
-	if (!state->pctl) {
+	if (IS_ERR(state->pctl)) {
 		dev_err(dev, "could not register TB10x pin driver\n");
-		ret = -EINVAL;
+		ret = PTR_ERR(state->pctl);
 		goto fail;
 	}
 

drivers/pinctrl/pinctrl-tegra-xusb.c

···
 	padctl->desc.owner = THIS_MODULE;
 
 	padctl->pinctrl = pinctrl_register(&padctl->desc, &pdev->dev, padctl);
-	if (!padctl->pinctrl) {
+	if (IS_ERR(padctl->pinctrl)) {
 		dev_err(&pdev->dev, "failed to register pincontrol\n");
-		err = -ENODEV;
+		err = PTR_ERR(padctl->pinctrl);
 		goto reset;
 	}
 

drivers/pinctrl/pinctrl-tegra.c

···
 	}
 
 	pmx->pctl = pinctrl_register(&tegra_pinctrl_desc, &pdev->dev, pmx);
-	if (!pmx->pctl) {
+	if (IS_ERR(pmx->pctl)) {
 		dev_err(&pdev->dev, "Couldn't register pinctrl driver\n");
-		return -ENODEV;
+		return PTR_ERR(pmx->pctl);
 	}
 
 	pinctrl_add_gpio_range(pmx->pctl, &tegra_pinctrl_gpio_range);

drivers/pinctrl/pinctrl-tz1090-pdc.c

···
 		return PTR_ERR(pmx->regs);
 
 	pmx->pctl = pinctrl_register(&tz1090_pdc_pinctrl_desc, &pdev->dev, pmx);
-	if (!pmx->pctl) {
+	if (IS_ERR(pmx->pctl)) {
 		dev_err(&pdev->dev, "Couldn't register pinctrl driver\n");
-		return -ENODEV;
+		return PTR_ERR(pmx->pctl);
 	}
 
 	platform_set_drvdata(pdev, pmx);

drivers/pinctrl/pinctrl-tz1090.c

···
 		return PTR_ERR(pmx->regs);
 
 	pmx->pctl = pinctrl_register(&tz1090_pinctrl_desc, &pdev->dev, pmx);
-	if (!pmx->pctl) {
+	if (IS_ERR(pmx->pctl)) {
 		dev_err(&pdev->dev, "Couldn't register pinctrl driver\n");
-		return -ENODEV;
+		return PTR_ERR(pmx->pctl);
 	}
 
 	platform_set_drvdata(pdev, pmx);

drivers/pinctrl/pinctrl-u300.c

···
 		return PTR_ERR(upmx->virtbase);
 
 	upmx->pctl = pinctrl_register(&u300_pmx_desc, &pdev->dev, upmx);
-	if (!upmx->pctl) {
+	if (IS_ERR(upmx->pctl)) {
 		dev_err(&pdev->dev, "could not register U300 pinmux driver\n");
-		return -EINVAL;
+		return PTR_ERR(upmx->pctl);
 	}
 
 	platform_set_drvdata(pdev, upmx);

drivers/pinctrl/pinctrl-zynq.c

···
 	pctrl->nfuncs = ARRAY_SIZE(zynq_pmux_functions);
 
 	pctrl->pctrl = pinctrl_register(&zynq_desc, &pdev->dev, pctrl);
-	if (!pctrl->pctrl)
-		return -ENOMEM;
+	if (IS_ERR(pctrl->pctrl))
+		return PTR_ERR(pctrl->pctrl);
 
 	platform_set_drvdata(pdev, pctrl);
 

drivers/pinctrl/qcom/pinctrl-msm.c

···
 	msm_pinctrl_desc.pins = pctrl->soc->pins;
 	msm_pinctrl_desc.npins = pctrl->soc->npins;
 	pctrl->pctrl = pinctrl_register(&msm_pinctrl_desc, &pdev->dev, pctrl);
-	if (!pctrl->pctrl) {
+	if (IS_ERR(pctrl->pctrl)) {
 		dev_err(&pdev->dev, "Couldn't register pinctrl driver\n");
-		return -ENODEV;
+		return PTR_ERR(pctrl->pctrl);
 	}
 
 	ret = msm_gpio_init(pctrl);

drivers/pinctrl/qcom/pinctrl-spmi-gpio.c

···
 	state->chip.can_sleep = false;
 
 	state->ctrl = pinctrl_register(pctrldesc, dev, state);
-	if (!state->ctrl)
-		return -ENODEV;
+	if (IS_ERR(state->ctrl))
+		return PTR_ERR(state->ctrl);
 
 	ret = gpiochip_add(&state->chip);
 	if (ret) {

drivers/pinctrl/qcom/pinctrl-spmi-mpp.c

···
 	state->chip.can_sleep = false;
 
 	state->ctrl = pinctrl_register(pctrldesc, dev, state);
-	if (!state->ctrl)
-		return -ENODEV;
+	if (IS_ERR(state->ctrl))
+		return PTR_ERR(state->ctrl);
 
 	ret = gpiochip_add(&state->chip);
 	if (ret) {

drivers/pinctrl/samsung/pinctrl-exynos5440.c

···
 		return ret;
 
 	pctl_dev = pinctrl_register(ctrldesc, &pdev->dev, priv);
-	if (!pctl_dev) {
+	if (IS_ERR(pctl_dev)) {
 		dev_err(&pdev->dev, "could not register pinctrl driver\n");
-		return -EINVAL;
+		return PTR_ERR(pctl_dev);
 	}
 
 	grange.name = "exynos5440-pctrl-gpio-range";

drivers/pinctrl/samsung/pinctrl-samsung.c

···
 		return ret;
 
 	drvdata->pctl_dev = pinctrl_register(ctrldesc, &pdev->dev, drvdata);
-	if (!drvdata->pctl_dev) {
+	if (IS_ERR(drvdata->pctl_dev)) {
 		dev_err(&pdev->dev, "could not register pinctrl driver\n");
-		return -EINVAL;
+		return PTR_ERR(drvdata->pctl_dev);
 	}
 
 	for (bank = 0; bank < drvdata->nr_banks; ++bank) {

drivers/pinctrl/sh-pfc/pinctrl.c

···
 	pmx->pctl_desc.npins = pfc->info->nr_pins;
 
 	pmx->pctl = pinctrl_register(&pmx->pctl_desc, pfc->dev, pmx);
-	if (pmx->pctl == NULL)
-		return -EINVAL;
+	if (IS_ERR(pmx->pctl))
+		return PTR_ERR(pmx->pctl);
 
 	return 0;
 }

drivers/pinctrl/sirf/pinctrl-atlas7.c

···
 
 	/* Now register the pin controller and all pins it handles */
 	pmx->pctl = pinctrl_register(&pmx->pctl_desc, &pdev->dev, pmx);
-	if (!pmx->pctl) {
+	if (IS_ERR(pmx->pctl)) {
 		dev_err(&pdev->dev, "could not register atlas7 pinmux driver\n");
-		ret = -EINVAL;
+		ret = PTR_ERR(pmx->pctl);
 		goto unmap_io;
 	}
 

drivers/pinctrl/sirf/pinctrl-sirf.c

···
 
 	/* Now register the pin controller and all pins it handles */
 	spmx->pmx = pinctrl_register(&sirfsoc_pinmux_desc, &pdev->dev, spmx);
-	if (!spmx->pmx) {
+	if (IS_ERR(spmx->pmx)) {
 		dev_err(&pdev->dev, "could not register SIRFSOC pinmux driver\n");
-		ret = -EINVAL;
+		ret = PTR_ERR(spmx->pmx);
 		goto out_no_pmx;
 	}
 

drivers/pinctrl/spear/pinctrl-spear.c

···
 	spear_pinctrl_desc.npins = machdata->npins;
 
 	pmx->pctl = pinctrl_register(&spear_pinctrl_desc, &pdev->dev, pmx);
-	if (!pmx->pctl) {
+	if (IS_ERR(pmx->pctl)) {
 		dev_err(&pdev->dev, "Couldn't register pinctrl driver\n");
-		return -ENODEV;
+		return PTR_ERR(pmx->pctl);
 	}
 
 	return 0;

drivers/pinctrl/sunxi/pinctrl-sunxi.c

···
 
 	pctl->pctl_dev = pinctrl_register(pctrl_desc,
 					  &pdev->dev, pctl);
-	if (!pctl->pctl_dev) {
+	if (IS_ERR(pctl->pctl_dev)) {
 		dev_err(&pdev->dev, "couldn't register pinctrl driver\n");
-		return -EINVAL;
+		return PTR_ERR(pctl->pctl_dev);
 	}
 
 	pctl->chip = devm_kzalloc(&pdev->dev, sizeof(*pctl->chip), GFP_KERNEL);

drivers/pinctrl/vt8500/pinctrl-wmt.c

···
 	data->dev = &pdev->dev;
 
 	data->pctl_dev = pinctrl_register(&wmt_desc, &pdev->dev, data);
-	if (!data->pctl_dev) {
+	if (IS_ERR(data->pctl_dev)) {
 		dev_err(&pdev->dev, "Failed to register pinctrl\n");
-		return -EINVAL;
+		return PTR_ERR(data->pctl_dev);
 	}
 
 	err = gpiochip_add(&data->gpio_chip);