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>

diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c
index 5dc1c79..836710c 100644 (file)
--- 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;

diff --git a/include/linux/rtc/ds1307.h b/include/linux/rtc/ds1307.h
new file mode 100644 (file)
index 0000000..291b1c4
--- /dev/null
+++ b/include/linux/rtc/ds1307.h
@@ -0,0 +1,22 @@
+/*
+ * ds1307.h - platform_data for the ds1307 (and variants) rtc driver
+ * (C) Copyright 2012 by Wolfram Sang, Pengutronix e.K.
+ * same license as the driver
+ */
+
+#ifndef _LINUX_DS1307_H
+#define _LINUX_DS1307_H
+
+#include <linux/types.h>
+
+#define DS1307_TRICKLE_CHARGER_250_OHM 0x01
+#define DS1307_TRICKLE_CHARGER_2K_OHM  0x02
+#define DS1307_TRICKLE_CHARGER_4K_OHM  0x03
+#define DS1307_TRICKLE_CHARGER_NO_DIODE        0x04
+#define DS1307_TRICKLE_CHARGER_DIODE   0x08
+
+struct ds1307_platform_data {
+       u8 trickle_charger_setup;
+};
+
+#endif /* _LINUX_DS1307_H */