+static int trickle_charger_of_init(struct device *dev, struct device_node *node)
+{
+ unsigned char reg;
+ int error;
+ u32 ohms = 0;
+
+ if (of_property_read_u32(node, "trickle-resistor-ohms" , &ohms))
+ return 0;
+
+ switch (ohms) {
+ case 180+940:
+ /*
+ * TCHE[3:0] == 0x05, TCH2 == 1, TCFE == 0 (charging
+ * over diode and 940ohm resistor)
+ */
+
+ if (of_property_read_bool(node, "trickle-diode-disable")) {
+ dev_err(dev, "diode and resistor mismatch\n");
+ return -EINVAL;
+ }
+ reg = 0x05;
+ break;
+
+ case 180+20000:
+ /* diode disabled */
+
+ if (!of_property_read_bool(node, "trickle-diode-disable")) {
+ dev_err(dev, "bq32k: diode and resistor mismatch\n");
+ return -EINVAL;
+ }
+ reg = 0x25;
+ break;
+
+ default:
+ dev_err(dev, "invalid resistor value (%d)\n", ohms);
+ return -EINVAL;
+ }
+
+ error = bq32k_write(dev, ®, BQ32K_CFG2, 1);
+ if (error)
+ return error;
+
+ reg = 0x20;
+ error = bq32k_write(dev, ®, BQ32K_TCH2, 1);
+ if (error)
+ return error;
+
+ dev_info(dev, "Enabled trickle RTC battery charge.\n");
+ return 0;
+}
+