devm_clk_get_optional_prepared
EXPORT_SYMBOL_GPL(devm_clk_get_optional_prepared);
drvdata->pclk = devm_clk_get_optional_prepared(dev, "pclk");
priv->oscclk = devm_clk_get_optional_prepared(dev, "oscclk");
struct clk *devm_clk_get_optional_prepared(struct device *dev, const char *id);