rtc: ds1307: add trickle charger support

Some DS13XX devices have "trickle chargers".  Its configuration register
is at different locations, the setup is the same, though.  Since the
configuration is board specific, introduce a platform_data to this driver.
Tested with a DS1339 on a custom board.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Cc: Alessandro Zummo <alessandro.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 16 insertions, 3 deletions

diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c
index 5dc1c7941199..836710ce750e 100644
--- a/drivers/rtc/rtc-ds1307.c
+++ b/drivers/rtc/rtc-ds1307.c
@@ -17,8 +17,7 @@
 #include <linux/string.h>
 #include <linux/rtc.h>
 #include <linux/bcd.h>
-
-
+#include <linux/rtc/ds1307.h>
 
 /*
  * We can't determine type by probing, but if we expect pre-Linux code
@@ -92,7 +91,8 @@ enum ds_type {
 #       define DS1337_BIT_A2I           0x02
 #       define DS1337_BIT_A1I           0x01
 #define DS1339_REG_ALARM1_SECS  0x07
-#define DS1339_REG_TRICKLE      0x10
+
+#define DS13XX_TRICKLE_CHARGER_MAGIC    0xa0
 
 #define RX8025_REG_CTRL1        0x0e
 #       define RX8025_BIT_2412          0x20
@@ -124,6 +124,7 @@ struct chip_desc {
         unsigned                alarm:1;
         u16                     nvram_offset;
         u16                     nvram_size;
+        u16                     trickle_charger_reg;
 };
 
 static const struct chip_desc chips[last_ds_type] = {
@@ -140,6 +141,13 @@ static const struct chip_desc chips[last_ds_type] = {
         },
         [ds_1339] = {
                 .alarm          = 1,
+                .trickle_charger_reg = 0x10,
+        },
+        [ds_1340] = {
+                .trickle_charger_reg = 0x08,
+        },
+        [ds_1388] = {
+                .trickle_charger_reg = 0x0a,
         },
         [ds_3231] = {
                 .alarm          = 1,
@@ -619,6 +627,7 @@ static int __devinit ds1307_probe(struct i2c_client *client,
         struct i2c_adapter      *adapter = to_i2c_adapter(client->dev.parent);
         int                     want_irq = false;
         unsigned char           *buf;
+        struct ds1307_platform_data *pdata = client->dev.platform_data;
         static const int        bbsqi_bitpos[] = {
                 [ds_1337] = 0,
                 [ds_1339] = DS1339_BIT_BBSQI,
@@ -638,6 +647,10 @@ static int __devinit ds1307_probe(struct i2c_client *client,
         ds1307->client  = client;
         ds1307->type    = id->driver_data;
 
+        if (pdata && pdata->trickle_charger_setup && chip->trickle_charger_reg)
+                i2c_smbus_write_byte_data(client, chip->trickle_charger_reg,
+                        DS13XX_TRICKLE_CHARGER_MAGIC | pdata->trickle_charger_setup);
+
         buf = ds1307->regs;
         if (i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) {
                 ds1307->read_block_data = i2c_smbus_read_i2c_block_data;