[bug report] pinctrl: eswin: Add EIC7700 pinctrl driver

[Dan Carpenter <dan.carpenter@linaro.org>]

Hello Yulin Lu,

Commit 5b797bcc00ef ("pinctrl: eswin: Add EIC7700 pinctrl driver")
from Jun 12, 2025 (linux-next), leads to the following Smatch static
checker warning:

	drivers/pinctrl/pinctrl-eic7700.c:638 eic7700_pinctrl_probe()
	warn: passing zero to 'PTR_ERR'

drivers/pinctrl/pinctrl-eic7700.c
    619 static int eic7700_pinctrl_probe(struct platform_device *pdev)
    620 {
    621         struct device *dev = &pdev->dev;
    622         struct pinctrl_dev *pctldev;
    623         struct eic7700_pinctrl *pc;
    624         struct regulator *regulator;
    625         u32 rgmii0_mode, rgmii1_mode;
    626         int ret, voltage;
    627 
    628         pc = devm_kzalloc(dev, struct_size(pc, functions, EIC7700_FUNCTIONS_COUNT), GFP_KERNEL);
    629         if (!pc)
    630                 return -ENOMEM;
    631 
    632         pc->base = devm_platform_ioremap_resource(pdev, 0);
    633         if (IS_ERR(pc->base))
    634                 return PTR_ERR(pc->base);
    635 
    636         regulator = devm_regulator_get(dev, "vrgmii");
    637         if (IS_ERR_OR_NULL(regulator)) {
--> 638                 return dev_err_probe(dev, PTR_ERR(regulator),

devm_regulator_get() will return NULL if CONFIG_REGULATOR is disabled.
PTR_ERR(NULL) is success.

    639                                          "failed to get vrgmii regulator\n");
    640         }
    641 
    642         voltage = regulator_get_voltage(regulator);
    643         if (voltage < 0) {
    644                 return dev_err_probe(&pdev->dev, voltage,
    645                          "Failed to get voltage from regulator\n");

If CONFIG_REGULATOR is disabled then this will return negative.  So this
driver can't work without a regulator.  Ideally the KConfig would enforce
that so we don't build drivers which can't work.

In that case the if (IS_ERR_OR_NULL()) check should be changed to
if (IS_ERR()) {.  See my blog for more details:
https://staticthinking.wordpress.com/2022/08/01/mixing-error-pointers-and-null/

    646         }
    647 
    648         rgmii0_mode = readl_relaxed(pc->base + EIC7700_RGMII0_SEL_MODE);

regards,
dan carpenter