1 files changed, 27 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c
index b2005b44e4f7..62b0763b7b9a 100644
--- a/drivers/rtc/rtc-ds1307.c
+++ b/drivers/rtc/rtc-ds1307.c
@@ -34,6 +34,7 @@ enum ds_type {
         ds_1388,
         ds_3231,
         m41t00,
+        mcp7941x,
         rx_8025,
         // rs5c372 too?  different address...
 };
@@ -43,6 +44,7 @@ enum ds_type {
 #define DS1307_REG_SECS         0x00    /* 00-59 */
 #       define DS1307_BIT_CH            0x80
 #       define DS1340_BIT_nEOSC         0x80
+#       define MCP7941X_BIT_ST          0x80
 #define DS1307_REG_MIN          0x01    /* 00-59 */
 #define DS1307_REG_HOUR         0x02    /* 00-23, or 1-12{am,pm} */
 #       define DS1307_BIT_12HR          0x40    /* in REG_HOUR */
@@ -50,6 +52,7 @@ enum ds_type {
 #       define DS1340_BIT_CENTURY_EN    0x80    /* in REG_HOUR */
 #       define DS1340_BIT_CENTURY       0x40    /* in REG_HOUR */
 #define DS1307_REG_WDAY         0x03    /* 01-07 */
+#       define MCP7941X_BIT_VBATEN      0x08
 #define DS1307_REG_MDAY         0x04    /* 01-31 */
 #define DS1307_REG_MONTH        0x05    /* 01-12 */
 #       define DS1337_BIT_CENTURY       0x80    /* in REG_MONTH */
@@ -137,6 +140,8 @@ static const struct chip_desc chips[] = {
 },
 [m41t00] = {
 },
+[mcp7941x] = {
+},
 [rx_8025] = {
 }, };
 
@@ -149,6 +154,7 @@ static const struct i2c_device_id ds1307_id[] = {
         { "ds1340", ds_1340 },
         { "ds3231", ds_3231 },
         { "m41t00", m41t00 },
+        { "mcp7941x", mcp7941x },
         { "pt7c4338", ds_1307 },
         { "rx8025", rx_8025 },
         { }
@@ -365,6 +371,10 @@ static int ds1307_set_time(struct device *dev, struct rtc_time *t)
                 buf[DS1307_REG_HOUR] |= DS1340_BIT_CENTURY_EN
                                 | DS1340_BIT_CENTURY;
                 break;
+        case mcp7941x:
+                buf[DS1307_REG_SECS] |= MCP7941X_BIT_ST;
+                buf[DS1307_REG_WDAY] |= MCP7941X_BIT_VBATEN;
+                break;
         default:
                 break;
         }
@@ -809,6 +819,23 @@ read_rtc:
                         dev_warn(&client->dev, "SET TIME!\n");
                 }
                 break;
+        case mcp7941x:
+                /* make sure that the backup battery is enabled */
+                if (!(ds1307->regs[DS1307_REG_WDAY] & MCP7941X_BIT_VBATEN)) {
+                        i2c_smbus_write_byte_data(client, DS1307_REG_WDAY,
+                                        ds1307->regs[DS1307_REG_WDAY]
+                                        | MCP7941X_BIT_VBATEN);
+                }
+
+                /* clock halted?  turn it on, so clock can tick. */
+                if (!(tmp & MCP7941X_BIT_ST)) {
+                        i2c_smbus_write_byte_data(client, DS1307_REG_SECS,
+                                        MCP7941X_BIT_ST);
+                        dev_warn(&client->dev, "SET TIME!\n");
+                        goto read_rtc;
+                }
+
+                break;
         case rx_8025:
         case ds_1337:
         case ds_1339: