rtc: rv3029: Add device tree property for trickle charger

The trickle charger resistor can be enabled via device tree
property trickle-resistor-ohms.

Signed-off-by: Michael Buesch <m@bues.ch>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

diff --git a/drivers/rtc/rtc-rv3029c2.c b/drivers/rtc/rtc-rv3029c2.c
index e59b8a54d9a7d3ca9c936ad05f3301cc29fba10a..b416ed026168a60205d59451af86f6f1aae1eca6 100644 (file)
--- a/drivers/rtc/rtc-rv3029c2.c
+++ b/drivers/rtc/rtc-rv3029c2.c
@@ -10,9 +10,6 @@
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  *
- * NOTE: Currently this driver only supports the bare minimum for read
- * and write the RTC and alarms. The extra features provided by this chip
- * (trickle charger, eeprom, T° compensation) are unavailable.
  */
 
 #include <linux/module.h>
@@ -528,6 +525,107 @@ static int rv3029_rtc_set_time(struct device *dev, struct rtc_time *tm)
        return rv3029_i2c_set_time(to_i2c_client(dev), tm);
 }
 
+static const struct rv3029_trickle_tab_elem {
+       u32 r;          /* resistance in ohms */
+       u8 conf;        /* trickle config bits */
+} rv3029_trickle_tab[] = {
+       {
+               .r      = 1076,
+               .conf   = RV3029_TRICKLE_1K | RV3029_TRICKLE_5K |
+                         RV3029_TRICKLE_20K | RV3029_TRICKLE_80K,
+       }, {
+               .r      = 1091,
+               .conf   = RV3029_TRICKLE_1K | RV3029_TRICKLE_5K |
+                         RV3029_TRICKLE_20K,
+       }, {
+               .r      = 1137,
+               .conf   = RV3029_TRICKLE_1K | RV3029_TRICKLE_5K |
+                         RV3029_TRICKLE_80K,
+       }, {
+               .r      = 1154,
+               .conf   = RV3029_TRICKLE_1K | RV3029_TRICKLE_5K,
+       }, {
+               .r      = 1371,
+               .conf   = RV3029_TRICKLE_1K | RV3029_TRICKLE_20K |
+                         RV3029_TRICKLE_80K,
+       }, {
+               .r      = 1395,
+               .conf   = RV3029_TRICKLE_1K | RV3029_TRICKLE_20K,
+       }, {
+               .r      = 1472,
+               .conf   = RV3029_TRICKLE_1K | RV3029_TRICKLE_80K,
+       }, {
+               .r      = 1500,
+               .conf   = RV3029_TRICKLE_1K,
+       }, {
+               .r      = 3810,
+               .conf   = RV3029_TRICKLE_5K | RV3029_TRICKLE_20K |
+                         RV3029_TRICKLE_80K,
+       }, {
+               .r      = 4000,
+               .conf   = RV3029_TRICKLE_5K | RV3029_TRICKLE_20K,
+       }, {
+               .r      = 4706,
+               .conf   = RV3029_TRICKLE_5K | RV3029_TRICKLE_80K,
+       }, {
+               .r      = 5000,
+               .conf   = RV3029_TRICKLE_5K,
+       }, {
+               .r      = 16000,
+               .conf   = RV3029_TRICKLE_20K | RV3029_TRICKLE_80K,
+       }, {
+               .r      = 20000,
+               .conf   = RV3029_TRICKLE_20K,
+       }, {
+               .r      = 80000,
+               .conf   = RV3029_TRICKLE_80K,
+       },
+};
+
+static void rv3029_trickle_config(struct i2c_client *client)
+{
+       struct device_node *of_node = client->dev.of_node;
+       const struct rv3029_trickle_tab_elem *elem;
+       int i, err;
+       u32 ohms;
+       u8 eectrl;
+
+       if (!of_node)
+               return;
+
+       /* Configure the trickle charger. */
+       err = rv3029_eeprom_read(client, RV3029_CONTROL_E2P_EECTRL,
+                                &eectrl, 1);
+       if (err < 0) {
+               dev_err(&client->dev,
+                       "Failed to read trickle charger config\n");
+               return;
+       }
+       err = of_property_read_u32(of_node, "trickle-resistor-ohms", &ohms);
+       if (err) {
+               /* Disable trickle charger. */
+               eectrl &= ~RV3029_TRICKLE_MASK;
+       } else {
+               /* Enable trickle charger. */
+               for (i = 0; i < ARRAY_SIZE(rv3029_trickle_tab); i++) {
+                       elem = &rv3029_trickle_tab[i];
+                       if (elem->r >= ohms)
+                               break;
+               }
+               eectrl &= ~RV3029_TRICKLE_MASK;
+               eectrl |= elem->conf;
+               dev_info(&client->dev,
+                        "Trickle charger enabled at %d ohms resistance.\n",
+                        elem->r);
+       }
+       err = rv3029_eeprom_write(client, RV3029_CONTROL_E2P_EECTRL,
+                                 &eectrl, 1);
+       if (err < 0) {
+               dev_err(&client->dev,
+                       "Failed to write trickle charger config\n");
+       }
+}
+
 static const struct rtc_class_ops rv3029_rtc_ops = {
        .read_time      = rv3029_rtc_read_time,
        .set_time       = rv3029_rtc_set_time,
@@ -558,6 +656,8 @@ static int rv3029_probe(struct i2c_client *client,
                return rc;
        }
 
+       rv3029_trickle_config(client);
+
        rtc = devm_rtc_device_register(&client->dev, client->name,
                                       &rv3029_rtc_ops, THIS_MODULE);