w1: ds2760_battery: add support for sleep mode feature

This adds support for ds2760's sleep mode feature. With this feature
enabled, the chip enters a deep sleep mode and disconnects from the
battery when the w1 line is held down for more than 2 seconds.

This new behaviour can be switched on and off using a new module
parameter.

Signed-off-by: Daniel Mack <daniel@caiaq.de>
Cc: Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>
Acked-by: Matt Reimer <mreimer@vpop.net>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>

2 files changed, 31 insertions, 0 deletions

diff --git a/drivers/power/ds2760_battery.c b/drivers/power/ds2760_battery.c
index 9331009090f1..520b5c49ff30 100644
--- a/drivers/power/ds2760_battery.c
+++ b/drivers/power/ds2760_battery.c
@@ -62,6 +62,10 @@ static unsigned int cache_time = 1000;
 module_param(cache_time, uint, 0644);
 MODULE_PARM_DESC(cache_time, "cache time in milliseconds");
 
+static unsigned int pmod_enabled;
+module_param(pmod_enabled, bool, 0644);
+MODULE_PARM_DESC(pmod_enabled, "PMOD enable bit");
+
 /* Some batteries have their rated capacity stored a N * 10 mAh, while
  * others use an index into this table. */
 static int rated_capacities[] = {
@@ -259,6 +263,17 @@ static void ds2760_battery_update_status(struct ds2760_device_info *di)
                 power_supply_changed(&di->bat);
 }
 
+static void ds2760_battery_write_status(struct ds2760_device_info *di,
+                                        char status)
+{
+        if (status == di->raw[DS2760_STATUS_REG])
+                return;
+
+        w1_ds2760_write(di->w1_dev, &status, DS2760_STATUS_WRITE_REG, 1);
+        w1_ds2760_store_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1);
+        w1_ds2760_recall_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1);
+}
+
 static void ds2760_battery_work(struct work_struct *work)
 {
         struct ds2760_device_info *di = container_of(work,
@@ -342,6 +357,7 @@ static enum power_supply_property ds2760_battery_props[] = {
 
 static int ds2760_battery_probe(struct platform_device *pdev)
 {
+        char status;
         int retval = 0;
         struct ds2760_device_info *di;
 
@@ -371,6 +387,16 @@ static int ds2760_battery_probe(struct platform_device *pdev)
                 goto batt_failed;
         }
 
+        /* enable sleep mode feature */
+        ds2760_battery_read_status(di);
+        status = di->raw[DS2760_STATUS_REG];
+        if (pmod_enabled)
+                status |= DS2760_STATUS_PMOD;
+        else
+                status &= ~DS2760_STATUS_PMOD;
+
+        ds2760_battery_write_status(di, status);
+
         INIT_DELAYED_WORK(&di->monitor_work, ds2760_battery_work);
         di->monitor_wqueue = create_singlethread_workqueue(dev_name(&pdev->dev));
         if (!di->monitor_wqueue) {
diff --git a/drivers/w1/slaves/w1_ds2760.h b/drivers/w1/slaves/w1_ds2760.h
index ea39419172a6..58e774141568 100644
--- a/drivers/w1/slaves/w1_ds2760.h
+++ b/drivers/w1/slaves/w1_ds2760.h
@@ -25,6 +25,10 @@
 
 #define DS2760_PROTECTION_REG           0x00
 #define DS2760_STATUS_REG               0x01
+        #define DS2760_STATUS_IE        (1 << 2)
+        #define DS2760_STATUS_SWEN      (1 << 3)
+        #define DS2760_STATUS_RNAOP     (1 << 4)
+        #define DS2760_STATUS_PMOD      (1 << 5)
 #define DS2760_EEPROM_REG               0x07
 #define DS2760_SPECIAL_FEATURE_REG      0x08
 #define DS2760_VOLTAGE_MSB              0x0c
@@ -38,6 +42,7 @@
 #define DS2760_EEPROM_BLOCK0            0x20
 #define DS2760_ACTIVE_FULL              0x20
 #define DS2760_EEPROM_BLOCK1            0x30
+#define DS2760_STATUS_WRITE_REG         0x31
 #define DS2760_RATED_CAPACITY           0x32
 #define DS2760_CURRENT_OFFSET_BIAS      0x33
 #define DS2760_ACTIVE_EMPTY             0x3b