twl4030_charger: Add backup-battery charging

This allows a voltage and current (bb_uvolts and bb_uamps) to be
specified in the platform_data, and charging of the backup battery will
be enabled with those specification.

As it is not possible to monitor the backup battery at all there is no
new device created to represent it.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>

2 files changed, 61 insertions, 0 deletions

diff --git a/drivers/power/twl4030_charger.c b/drivers/power/twl4030_charger.c
index 3e6e9910110..0511610b235 100644
--- a/drivers/power/twl4030_charger.c
+++ b/drivers/power/twl4030_charger.c
@@ -28,6 +28,7 @@
 #define TWL4030_BCIVBUS         0x0c
 #define TWL4030_BCIMFSTS4       0x10
 #define TWL4030_BCICTL1         0x23
+#define TWL4030_BB_CFG          0x12
 
 #define TWL4030_BCIAUTOWEN      BIT(5)
 #define TWL4030_CONFIG_DONE     BIT(4)
@@ -37,6 +38,17 @@
 #define TWL4030_USBFASTMCHG     BIT(2)
 #define TWL4030_STS_VBUS        BIT(7)
 #define TWL4030_STS_USB_ID      BIT(2)
+#define TWL4030_BBCHEN          BIT(4)
+#define TWL4030_BBSEL_MASK      0b1100
+#define TWL4030_BBSEL_2V5       0b0000
+#define TWL4030_BBSEL_3V0       0b0100
+#define TWL4030_BBSEL_3V1       0b1000
+#define TWL4030_BBSEL_3V2       0b1100
+#define TWL4030_BBISEL_MASK     0b11
+#define TWL4030_BBISEL_25uA     0b00
+#define TWL4030_BBISEL_150uA    0b01
+#define TWL4030_BBISEL_500uA    0b10
+#define TWL4030_BBISEL_1000uA   0b11
 
 /* BCI interrupts */
 #define TWL4030_WOVF            BIT(0) /* Watchdog overflow */
@@ -202,6 +214,49 @@ static int twl4030_charger_enable_ac(bool enable)
 }
 
 /*
+ * Enable/Disable charging of Backup Battery.
+ */
+static int twl4030_charger_enable_backup(int uvolt, int uamp)
+{
+        int ret;
+        u8 flags;
+
+        if (uvolt < 2500000 ||
+            uamp < 25) {
+                /* disable charging of backup battery */
+                ret = twl4030_clear_set(TWL4030_MODULE_PM_RECEIVER,
+                                        TWL4030_BBCHEN, 0, TWL4030_BB_CFG);
+                return ret;
+        }
+
+        flags = TWL4030_BBCHEN;
+        if (uvolt >= 3200000)
+                flags |= TWL4030_BBSEL_3V2;
+        else if (uvolt >= 3100000)
+                flags |= TWL4030_BBSEL_3V1;
+        else if (uvolt >= 3000000)
+                flags |= TWL4030_BBSEL_3V0;
+        else
+                flags |= TWL4030_BBSEL_2V5;
+
+        if (uamp >= 1000)
+                flags |= TWL4030_BBISEL_1000uA;
+        else if (uamp >= 500)
+                flags |= TWL4030_BBISEL_500uA;
+        else if (uamp >= 150)
+                flags |= TWL4030_BBISEL_150uA;
+        else
+                flags |= TWL4030_BBISEL_25uA;
+
+        ret = twl4030_clear_set(TWL4030_MODULE_PM_RECEIVER,
+                                TWL4030_BBSEL_MASK | TWL4030_BBISEL_MASK,
+                                flags,
+                                TWL4030_BB_CFG);
+
+        return ret;
+}
+
+/*
  * TWL4030 CHG_PRES (AC charger presence) events
  */
 static irqreturn_t twl4030_charger_interrupt(int irq, void *arg)
@@ -424,6 +479,7 @@ static enum power_supply_property twl4030_charger_props[] = {
 static int __init twl4030_bci_probe(struct platform_device *pdev)
 {
         struct twl4030_bci *bci;
+        struct twl4030_bci_platform_data *pdata = pdev->dev.platform_data;
         int ret;
         u32 reg;
 
@@ -503,6 +559,8 @@ static int __init twl4030_bci_probe(struct platform_device *pdev)
 
         twl4030_charger_enable_ac(true);
         twl4030_charger_enable_usb(bci, true);
+        twl4030_charger_enable_backup(pdata->bb_uvolt,
+                                      pdata->bb_uamp);
 
         return 0;
 
@@ -531,6 +589,7 @@ static int __exit twl4030_bci_remove(struct platform_device *pdev)
 
         twl4030_charger_enable_ac(false);
         twl4030_charger_enable_usb(bci, false);
+        twl4030_charger_enable_backup(0, 0);
 
         /* mask interrupts */
         twl_i2c_write_u8(TWL4030_MODULE_INTERRUPTS, 0xff,
diff --git a/include/linux/i2c/twl.h b/include/linux/i2c/twl.h
index 3993477103a..8eec4403b17 100644
--- a/include/linux/i2c/twl.h
+++ b/include/linux/i2c/twl.h
@@ -555,6 +555,8 @@ struct twl4030_clock_init_data {
 struct twl4030_bci_platform_data {
         int *battery_tmp_tbl;
         unsigned int tblsize;
+        int     bb_uvolt;       /* voltage to charge backup battery */
+        int     bb_uamp;        /* current for backup battery charging */
 };
 
 /* TWL4030_GPIO_MAX (18) GPIOs, with interrupts */