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>

1 files changed, 103 insertions, 3 deletions

diff --git a/drivers/rtc/rtc-rv3029c2.c b/drivers/rtc/rtc-rv3029c2.c
index e59b8a54d9a7..b416ed026168 100644
--- 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);