pmic: Add support for setting transmission length in uclass private data

The struct uc_pmic_priv's trans_len field stores the number of types to
be transmitted per PMIC transfer.
Signed-off-by: NLukasz Majewski <lukma@denx.de>
Reviewed-by: NSimon Glass <sjg@chromium.org>

drivers/power/pmic/pmic-uclass.c

@@ -165,7 +165,17 @@ int pmic_clrsetbits(struct udevice *dev, uint reg, uint clr, uint set)
 	return pmic_reg_write(dev, reg, byte);
 }
 
+static int pmic_pre_probe(struct udevice *dev)
+{
+	struct uc_pmic_priv *pmic_priv = dev_get_uclass_priv(dev);
+
+	pmic_priv->trans_len = 1;
+	return 0;
+}
+
 UCLASS_DRIVER(pmic) = {
 	.id		= UCLASS_PMIC,
 	.name		= "pmic",
+	.pre_probe	= pmic_pre_probe,
+	.per_device_auto_alloc_size = sizeof(struct uc_pmic_priv),
 };

include/power/pmic.h

@@ -297,6 +297,15 @@ int pmic_reg_write(struct udevice *dev, uint reg, uint value);
  */
 int pmic_clrsetbits(struct udevice *dev, uint reg, uint clr, uint set);
 
+/*
+ * This structure holds the private data for PMIC uclass
+ * For now we store information about the number of bytes
+ * being sent at once to the device.
+ */
+struct uc_pmic_priv {
+	uint trans_len;
+};
+
 #endif /* CONFIG_DM_PMIC */
 
 #ifdef CONFIG_POWER