如何使用devm_regulator_get处理错误

Question

当devm_regulator_get找不到匹配的调节器时，我正试图处理这个案子。我在内核4.9.30上编程

从linux内核源代码我们可以看到以下描述[drivers/regulator/devres.c / drivers/regulator/core.c]

司机/调节器/ devres.c

/**
 * devm_regulator_get - Resource managed regulator_get()
 * @dev: device for regulator "consumer"
 * @id: Supply name or regulator ID.
 *
 * Managed regulator_get(). Regulators returned from this function are
 * automatically regulator_put() on driver detach. See regulator_get() for more
 * information.
 */
struct regulator *devm_regulator_get(struct device *dev, const char *id)
{
    return _devm_regulator_get(dev, id, NORMAL_GET);
}
EXPORT_SYMBOL_GPL(devm_regulator_get);

司机/调节器/ core.c

/**
 * regulator_get - lookup and obtain a reference to a regulator.
 * @dev: device for regulator "consumer"
 * @id: Supply name or regulator ID.
 *
 * Returns a struct regulator corresponding to the regulator producer,
 * or IS_ERR() condition containing errno.
 *
 * Use of supply names configured via regulator_set_device_supply() is
 * strongly encouraged.  It is recommended that the supply name used
 * should match the name used for the supply and/or the relevant
 * device pins in the datasheet.
 */
struct regulator *regulator_get(struct device *dev, const char *id)
{
    return _regulator_get(dev, id, false, true);
}
EXPORT_SYMBOL_GPL(regulator_get);

这是我的代码

struct regulator *power_regulator = devm_regulator_get(&pdev->dev, "zdfhkfgv");
if(IS_ERR(power_regulator))
{
    ERROR("Invalid power regulator\r\n");
    return -EINVAL;
}

然而，即使找不到调节器，我也永远不会陷入错误的情况。

这是内核输出：

# insmod mod.ko 
module : Init driver
module : Device allocated and initialized
module supply zdfhkfgv not found, using dummy regulator
module : device is not powered
[...]

所以我可以看到devm_regulator_get未能找到监管机构，但我没有陷入错误的情况。这非常令人讨厌，因为当调节器未设置时，我将返回。而不是代码继续运行与未供电的设备。

我在这做错了什么？

Answer 1

如果您不想依赖虚拟调节器，则应使用devm_regulator_get_optional（）。然后它将返回-ENODEV。