On Tue, Jan 19, 2021 at 11:14:20AM +0100, Mauro Carvalho Chehab wrote:

+int hi6421_spmi_pmic_read(struct hi6421_spmi_pmic *pmic, int reg)
+{
+	struct spmi_device *pdev;
+	u8 read_value = 0;
+	u32 ret;
+
+	pdev = to_spmi_device(pmic->dev);
+	if (!pdev) {
+		pr_err("%s: pdev get failed!\n", __func__);
+		return -ENODEV;
+	}
+
+	ret = spmi_ext_register_readl(pdev, reg, &read_value, 1);
+	if (ret) {
+		pr_err("%s: spmi_ext_register_readl failed!\n", __func__);
+		return ret;
+	}
+	return read_value;
+}
+EXPORT_SYMBOL(hi6421_spmi_pmic_read);

The I/O here looks a lot like regmap_spmi_ext.