Re: USB charging over TPS65950 BCI

[Gregoire Gentil <gregoire@gentil.com>]

[-- Attachment #1: Type: text/plain, Size: 12918 bytes --]

On Fri, 2009-07-31 at 19:19 +0530, pramod gurav wrote:
> Hi All,
> I was trying to get the USB battery charging working over TPS65950 BCI
> on the OMAP3430 custom board. I am working with linux-omap-2.6
> v2.6.28-omap1 tag. I enabled the TWL4030 MADC and TWL4030 BCI drivers.
> I passed interrupt details to these drivers from platform_device
> structure from my board file. I could get the AC charging working. The
> AC and USB detection worked. However the USB charging is not
> happening.
> I read through the TPS TRM and took the dumps of the registers from
> BCI and some from TWL USB module and BOOT_BCI whenever I plug in the
> USB charger between host and the board. The register settings seem to
> be fine. But the battery is not charging. I am using BQ27000 chip for
> battery monitoring and I can see the battery voltage is decreasing.
> 
> Following are the register dumps of TWL with and without USB plugged in:
> 
> These are the register contents when USB charger is plugged in:
> BCIMDEN         = 0x11
> REG_BOOT_BCI    = 0x37
> REG_POWER_CTRL  = 0x20
> REG_BCIMFSTS4   = 0xf4
> REG_BCIMFSTS1   = 0x13
> REG_BCIIREF1    = 0x68
> REG_BCIIREF2    = 0x3
> REG_BCIMFEN4    = 0x6f
> REG_BCIMFSTS2   = 0x0
> REG_BCIMSTATEC  = 0x12
> REG_STS_HW_CONDITIONS= 0x90
> 
> 
> These are the register contents when USB charger is plugged out:
> BCIMDEN         = 0x0
> REG_BOOT_BCI    = 0x35
> REG_POWER_CTRL  = 0x20
> REG_BCIMFSTS4   = 0xf0
> REG_BCIMFSTS1   = 0xaa
> REG_BCIIREF1    = 0x68
> REG_BCIIREF2    = 0x3
> REG_BCIMFEN4    = 0x68
> REG_BCIMFSTS2   = 0x0
> REG_BCIMSTATEC  =0x0
> REG_STS_HW_CONDITIONS= 0x10
> 
> Is there anything more I need to support to get BCI USB charging
> working? Need I follow any USB Communication protocol between Host and
> the board.
> I have pasted the kernel boot logs for reference at the end.
> Can any one please guide me to some pointers?
> 
> -- 
> Best Regards
> Pramod
I'm experiencing some problems with TWL4030 DC charging and I'm
interested by this kind of problem. Basically, the values reported by
our patch is different from the current going to the battery. We wrote
the attached enhanced patch so as to edit at run-time the charging mode
and various values including charge_current. It's against 2.6.29 but I
think that it should work again 2.6.28. Unfortunately, starting 2.6.30,
Tony has removed all the BCI battery code and has asked for updated code
against mainline but I've not seen anything so far.

Pramod, can you try the attached patch (perhaps, it will help you) and
can you tell if you see the exact current going to the battery reported
by the driver?

Grégoire





--- a/drivers/power/twl4030_bci_battery.c	2009-07-22 18:27:16.000000000
-0700
+++ b/drivers/power/twl4030_bci_battery.c	2009-07-22 18:30:22.000000000
-0700
@@ -15,6 +15,9 @@
  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  */
 
+/* Boot with automatic charge */
+#define CHARGE_MODE 1
+
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/device.h>
@@ -50,6 +53,7 @@
 /* Boot BCI flag bits */
 #define BCIAUTOWEN		0x020
 #define CONFIG_DONE		0x010
+#define CVENAC			0x004
 #define BCIAUTOUSB		0x002
 #define BCIAUTOAC		0x001
 #define BCIMSTAT_MASK		0x03F
@@ -81,6 +85,11 @@
 #define REG_BB_CFG		0x012
 #define BBCHEN			0x010
 
+/* GPBR */
+#define REG_GPBR1		0x0c
+#define MADC_HFCLK_EN		0x80
+#define DEFAULT_MADC_CLK_EN	0x10
+
 /* Power supply charge interrupt */
 #define REG_PWR_ISR1		0x00
 #define REG_PWR_IMR1		0x01
@@ -125,6 +134,18 @@
 /* BCIEDR3 */
 #define	VBATLVL_EDRRISIN	0x02
 
+/* BCIIREF1 */
+#define REG_BCIIREF1		0x027
+#define REG_BCIIREF2		0x028
+
+/* BCIMFTH1 */
+#define REG_BCIMFTH1		0x016
+
+/* Key */
+#define KEY_IIREF		0xE7
+#define KEY_FTH1		0xD2
+#define REG_BCIMFKEY		0x011
+
 /* Step size and prescaler ratio */
 #define TEMP_STEP_SIZE		147
 #define TEMP_PSR_R		100
@@ -142,9 +163,6 @@
 #define ENABLE		1
 #define DISABLE		1
 
-/* Ptr to thermistor table */
-int *therm_tbl;
-
 struct twl4030_bci_device_info {
 	struct device		*dev;
 
@@ -160,6 +178,8 @@
 	struct power_supply	bk_bat;
 	struct delayed_work	twl4030_bci_monitor_work;
 	struct delayed_work	twl4030_bk_bci_monitor_work;
+
+	struct twl4030_bci_platform_data *pdata;
 };
 
 static int usb_charger_flag;
@@ -425,15 +445,21 @@
 /*
  * Enable/Disable AC Charge funtionality.
  */
-static int twl4030charger_ac_en(int enable)
+static int twl4030charger_ac_en(int enable, int automatic)
 {
 	int ret;
 
 	if (enable) {
 		/* forcing the field BCIAUTOAC (BOOT_BCI[0) to 1 */
-		ret = clear_n_set(TWL4030_MODULE_PM_MASTER, 0,
-			(CONFIG_DONE | BCIAUTOWEN | BCIAUTOAC),
-			REG_BOOT_BCI);
+		if(!automatic) {
+			ret = clear_n_set(TWL4030_MODULE_PM_MASTER, BCIAUTOAC | CVENAC,
+				(CONFIG_DONE | BCIAUTOWEN),
+				REG_BOOT_BCI);
+		} else {
+			ret = clear_n_set(TWL4030_MODULE_PM_MASTER, 0,
+				(CONFIG_DONE | BCIAUTOWEN | BCIAUTOAC | CVENAC),
+				REG_BOOT_BCI);
+		}
 		if (ret)
 			return ret;
 	} else {
@@ -518,11 +544,15 @@
  * Return battery temperature
  * Or < 0 on failure.
  */
-static int twl4030battery_temperature(void)
+static int twl4030battery_temperature(struct twl4030_bci_device_info
*di)
 {
 	u8 val;
 	int temp, curr, volt, res, ret;
 
+	/* Is a temperature table specified? */
+	if (!di->pdata->tblsize)
+		return 0;
+
 	/* Getting and calculating the thermistor voltage */
 	ret = read_bci_val(T2_BATTERY_TEMP);
 	if (ret < 0)
@@ -543,7 +573,7 @@
 
 	/*calculating temperature*/
 	for (temp = 58; temp >= 0; temp--) {
-		int actual = therm_tbl[temp];
+		int actual = di->pdata->battery_tmp_tbl[temp];
 		if ((actual - res) >= 0)
 			break;
 	}
@@ -661,6 +691,9 @@
 		return ret;
 	}
 
+#ifdef DEBUG
+	printk("BCI DEBUG: BCIMSTATEC Charge state is 0x%x\n", status);
+#endif
 	return (int) (status & BCIMSTAT_MASK);
 }
 
@@ -709,14 +742,43 @@
  */
 static int twl4030battery_temp_setup(void)
 {
-	int ret;
+#ifdef DEBUG
+	u8 i;
+#endif
+	u8 ret;
 
 	/* Enabling thermistor current */
-	ret = clear_n_set(TWL4030_MODULE_MAIN_CHARGE, 0, ITHEN,
+	ret = clear_n_set(TWL4030_MODULE_MAIN_CHARGE, 0, 0x1B,
 		REG_BCICTL1);
 	if (ret)
 		return ret;
 
+#ifdef DEBUG
+	twl4030_i2c_read_u8(TWL4030_MODULE_PM_MASTER, &ret, REG_BOOT_BCI);
+	printk("BCI DEBUG: BOOT_BCI Value is 0x%x\n", ret);
+
+	twl4030_i2c_read_u8(TWL4030_MODULE_PM_MASTER, &ret,
REG_STS_HW_CONDITIONS);
+	printk("BCI DEBUG: STS_HW_CONDITIONS Value is 0x%x\n", ret);
+
+	twl4030_i2c_read_u8(TWL4030_MODULE_MAIN_CHARGE, &ret, REG_BCICTL1);
+	printk("BCI DEBUG: BCICTL1 Value is 0x%x\n", ret);
+
+	twl4030_i2c_read_u8(TWL4030_MODULE_MAIN_CHARGE, &ret, REG_BCICTL2);
+	printk("BCI DEBUG: BCICTL2 Value is 0x%x\n", ret);
+
+	twl4030_i2c_read_u8(TWL4030_MODULE_MAIN_CHARGE, &ret, 0x0);
+	printk("BCI DEBUG: BCIMDEN Value is 0x%x\n", ret);
+
+	twl4030_i2c_read_u8(TWL4030_MODULE_INTBR, &ret, REG_GPBR1);
+	printk("BCI DEBUG: GPBR1 Value is 0x%x\n", ret);
+
+	for(i = 0x0; i <= 0x32; i++)
+	{
+		twl4030_i2c_read_u8(TWL4030_MODULE_MAIN_CHARGE, &ret, i);
+		printk("BCI DEBUG: BCI 0x%x Value is 0x%x\n", i, ret);
+	}
+#endif
+
 	return 0;
 }
 
@@ -732,7 +794,6 @@
 	ret = twl4030_i2c_read_u8(mod_no, &val, reg);
 	if (ret)
 		return ret;
-
 	/* Clearing all those bits to clear */
 	val &= ~(clear);
 
@@ -772,13 +833,14 @@
 		struct twl4030_bci_device_info,
 		twl4030_bk_bci_monitor_work.work);
 
-	twl4030_bk_bci_battery_read_status(di);
+	if(!di->pdata->no_backup_battery)
+		twl4030_bk_bci_battery_read_status(di);
 	schedule_delayed_work(&di->twl4030_bk_bci_monitor_work, 500);
 }
 
 static void twl4030_bci_battery_read_status(struct
twl4030_bci_device_info *di)
 {
-	di->temp_C = twl4030battery_temperature();
+	di->temp_C = twl4030battery_temperature(di);
 	di->voltage_uV = twl4030battery_voltage();
 	di->current_uA = twl4030battery_current();
 }
@@ -819,6 +881,87 @@
 #define to_twl4030_bk_bci_device_info(x) container_of((x), \
 		struct twl4030_bci_device_info, bk_bat);
 
+static ssize_t
+show_charge_current(struct device *dev, struct device_attribute *attr,
char *buf)
+{
+	u8  ctl;
+	int ret = read_bci_val(REG_BCIIREF1) & 0x1FF;
+	twl4030_i2c_read_u8(TWL4030_MODULE_MAIN_CHARGE, &ctl, REG_BCICTL1);
+
+	if (ctl & CGAIN)
+		ret |= 0x200;
+
+#ifdef DEBUG
+	/* Dump debug */
+	twl4030battery_temp_setup();
+#endif
+
+	return sprintf(buf, "%d\n", ret);
+}
+
+static ssize_t
+set_charge_current(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
+{
+	unsigned long newCurrent;
+	int ret;
+
+	ret = strict_strtoul(buf, 10, &newCurrent);
+	if (ret)
+		return -EINVAL;
+
+	ret = twl4030_i2c_write_u8(TWL4030_MODULE_MAIN_CHARGE, KEY_IIREF,
REG_BCIMFKEY);
+	if (ret)
+		return ret;
+
+	ret = twl4030_i2c_write_u8(TWL4030_MODULE_MAIN_CHARGE, newCurrent &
0xff, REG_BCIIREF1);
+	if (ret)
+		return ret;
+
+	ret = twl4030_i2c_write_u8(TWL4030_MODULE_MAIN_CHARGE, KEY_IIREF,
REG_BCIMFKEY);
+	if (ret)
+		return ret;
+
+	ret = twl4030_i2c_write_u8(TWL4030_MODULE_MAIN_CHARGE, (newCurrent >>
8) & 0x1, REG_BCIIREF2);
+	if (ret)
+		return ret;
+
+	/* Set software-controlled charge */
+	twl4030charger_ac_en(ENABLE, 0);
+
+	/* Set CGAIN = 0 or 1 */
+	if(newCurrent > 511) {
+		u8 tmp;
+
+		/* Set CGAIN = 1 -- need to wait until automatic charge turns off */
+		while(!ret) {
+			clear_n_set(TWL4030_MODULE_MAIN_CHARGE, 0, CGAIN | 0x1B,
REG_BCICTL1);
+			twl4030_i2c_read_u8(TWL4030_MODULE_MAIN_CHARGE, &tmp, REG_BCICTL1);
+
+			ret = tmp & CGAIN;
+			if(!ret)
+				mdelay(50);
+		}
+	} else {
+		u8 tmp;
+
+		/* Set CGAIN = 0 -- need to wait until automatic charge turns off */
+		while(!ret) {
+			clear_n_set(TWL4030_MODULE_MAIN_CHARGE, CGAIN, 0x1B, REG_BCICTL1);
+			twl4030_i2c_read_u8(TWL4030_MODULE_MAIN_CHARGE, &tmp, REG_BCICTL1);
+
+			ret = !(tmp & CGAIN);
+			if(!ret)
+				mdelay(50);
+		}
+	}
+
+	/* Set automatic charge (CGAIN = 0/1 persists) */
+	twl4030charger_ac_en(ENABLE, 1);
+
+	return count;
+}
+static DEVICE_ATTR(charge_current, S_IRUGO | S_IWUSR,
show_charge_current, set_charge_current);
+
 static int twl4030_bk_bci_battery_get_property(struct power_supply
*psy,
 					enum power_supply_property psp,
 					union power_supply_propval *val)
@@ -912,8 +1055,6 @@
 	int irq;
 	int ret;
 
-	therm_tbl = pdata->battery_tmp_tbl;
-
 	di = kzalloc(sizeof(*di), GFP_KERNEL);
 	if (!di)
 		return -ENOMEM;
@@ -937,8 +1078,12 @@
 	di->bk_bat.num_properties = ARRAY_SIZE(twl4030_bk_bci_battery_props);
 	di->bk_bat.get_property = twl4030_bk_bci_battery_get_property;
 	di->bk_bat.external_power_changed = NULL;
+	di->pdata = pdata;
 
-	twl4030charger_ac_en(ENABLE);
+	/* Set up clocks */
+	twl4030_i2c_write_u8(TWL4030_MODULE_INTBR, MADC_HFCLK_EN |
DEFAULT_MADC_CLK_EN, REG_GPBR1);
+
+	twl4030charger_ac_en(ENABLE, CHARGE_MODE);
 	twl4030charger_usb_en(ENABLE);
 	twl4030battery_hw_level_en(ENABLE);
 	twl4030battery_hw_presence_en(ENABLE);
@@ -951,9 +1096,12 @@
 		goto temp_setup_fail;
 
 	/* enabling GPCH09 for read back battery voltage */
-	ret = twl4030backupbatt_voltage_setup();
-	if (ret)
-		goto voltage_setup_fail;
+	if(!di->pdata->no_backup_battery)
+	{
+		ret = twl4030backupbatt_voltage_setup();
+		if (ret)
+			goto voltage_setup_fail;
+	}
 
 	/* REVISIT do we need to request both IRQs ?? */
 
@@ -988,9 +1136,18 @@
 				twl4030_bci_battery_work);
 	schedule_delayed_work(&di->twl4030_bci_monitor_work, 0);
 
-	ret = power_supply_register(&pdev->dev, &di->bk_bat);
+	if(!pdata->no_backup_battery)
+	{
+		ret = power_supply_register(&pdev->dev, &di->bk_bat);
+		if (ret) {
+			dev_dbg(&pdev->dev, "failed to register backup battery\n");
+			goto bk_batt_failed;
+		}
+	}
+
+	ret = device_create_file(di->bat.dev, &dev_attr_charge_current);
 	if (ret) {
-		dev_dbg(&pdev->dev, "failed to register backup battery\n");
+		dev_err(&pdev->dev, "failed to create sysfs entries\n");
 		goto bk_batt_failed;
 	}
 
@@ -1001,7 +1158,8 @@
 	return 0;
 
 bk_batt_failed:
-	power_supply_unregister(&di->bat);
+	if(!pdata->no_backup_battery)
+		power_supply_unregister(&di->bat);
 batt_failed:
 	free_irq(irq, di);
 chg_irq_fail:
@@ -1010,7 +1168,7 @@
 batt_irq_fail:
 voltage_setup_fail:
 temp_setup_fail:
-	twl4030charger_ac_en(DISABLE);
+	twl4030charger_ac_en(DISABLE, CHARGE_MODE);
 	twl4030charger_usb_en(DISABLE);
 	twl4030battery_hw_level_en(DISABLE);
 	twl4030battery_hw_presence_en(DISABLE);
@@ -1024,7 +1182,7 @@
 	struct twl4030_bci_device_info *di = platform_get_drvdata(pdev);
 	int irq;
 
-	twl4030charger_ac_en(DISABLE);
+	twl4030charger_ac_en(DISABLE, CHARGE_MODE);
 	twl4030charger_usb_en(DISABLE);
 	twl4030battery_hw_level_en(DISABLE);
 	twl4030battery_hw_presence_en(DISABLE);
--- a/include/linux/i2c/twl4030.h
+++ b/include/linux/i2c/twl4030.h
@@ -299,6 +299,8 @@ int twl4030_i2c_read(u8 mod_no, u8 *value, u8 reg,
unsigned num_bytes);
 struct twl4030_bci_platform_data {
 	int *battery_tmp_tbl;
 	unsigned int tblsize;
+
+	bool no_backup_battery;
 };
 
 /* TWL4030_GPIO_MAX (18) GPIOs, with interrupts */


[-- Attachment #2: twl4030_bci_battery.patch --]
[-- Type: text/x-patch, Size: 10277 bytes --]

--- a/drivers/power/twl4030_bci_battery.c	2009-07-22 18:27:16.000000000 -0700
+++ b/drivers/power/twl4030_bci_battery.c	2009-07-22 18:30:22.000000000 -0700
@@ -15,6 +15,9 @@
  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  */
 
+/* Boot with automatic charge */
+#define CHARGE_MODE 1
+
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/device.h>
@@ -50,6 +53,7 @@
 /* Boot BCI flag bits */
 #define BCIAUTOWEN		0x020
 #define CONFIG_DONE		0x010
+#define CVENAC			0x004
 #define BCIAUTOUSB		0x002
 #define BCIAUTOAC		0x001
 #define BCIMSTAT_MASK		0x03F
@@ -81,6 +85,11 @@
 #define REG_BB_CFG		0x012
 #define BBCHEN			0x010
 
+/* GPBR */
+#define REG_GPBR1		0x0c
+#define MADC_HFCLK_EN		0x80
+#define DEFAULT_MADC_CLK_EN	0x10
+
 /* Power supply charge interrupt */
 #define REG_PWR_ISR1		0x00
 #define REG_PWR_IMR1		0x01
@@ -125,6 +134,18 @@
 /* BCIEDR3 */
 #define	VBATLVL_EDRRISIN	0x02
 
+/* BCIIREF1 */
+#define REG_BCIIREF1		0x027
+#define REG_BCIIREF2		0x028
+
+/* BCIMFTH1 */
+#define REG_BCIMFTH1		0x016
+
+/* Key */
+#define KEY_IIREF		0xE7
+#define KEY_FTH1		0xD2
+#define REG_BCIMFKEY		0x011
+
 /* Step size and prescaler ratio */
 #define TEMP_STEP_SIZE		147
 #define TEMP_PSR_R		100
@@ -142,9 +163,6 @@
 #define ENABLE		1
 #define DISABLE		1
 
-/* Ptr to thermistor table */
-int *therm_tbl;
-
 struct twl4030_bci_device_info {
 	struct device		*dev;
 
@@ -160,6 +178,8 @@
 	struct power_supply	bk_bat;
 	struct delayed_work	twl4030_bci_monitor_work;
 	struct delayed_work	twl4030_bk_bci_monitor_work;
+
+	struct twl4030_bci_platform_data *pdata;
 };
 
 static int usb_charger_flag;
@@ -425,15 +445,21 @@
 /*
  * Enable/Disable AC Charge funtionality.
  */
-static int twl4030charger_ac_en(int enable)
+static int twl4030charger_ac_en(int enable, int automatic)
 {
 	int ret;
 
 	if (enable) {
 		/* forcing the field BCIAUTOAC (BOOT_BCI[0) to 1 */
-		ret = clear_n_set(TWL4030_MODULE_PM_MASTER, 0,
-			(CONFIG_DONE | BCIAUTOWEN | BCIAUTOAC),
-			REG_BOOT_BCI);
+		if(!automatic) {
+			ret = clear_n_set(TWL4030_MODULE_PM_MASTER, BCIAUTOAC | CVENAC,
+				(CONFIG_DONE | BCIAUTOWEN),
+				REG_BOOT_BCI);
+		} else {
+			ret = clear_n_set(TWL4030_MODULE_PM_MASTER, 0,
+				(CONFIG_DONE | BCIAUTOWEN | BCIAUTOAC | CVENAC),
+				REG_BOOT_BCI);
+		}
 		if (ret)
 			return ret;
 	} else {
@@ -518,11 +544,15 @@
  * Return battery temperature
  * Or < 0 on failure.
  */
-static int twl4030battery_temperature(void)
+static int twl4030battery_temperature(struct twl4030_bci_device_info *di)
 {
 	u8 val;
 	int temp, curr, volt, res, ret;
 
+	/* Is a temperature table specified? */
+	if (!di->pdata->tblsize)
+		return 0;
+
 	/* Getting and calculating the thermistor voltage */
 	ret = read_bci_val(T2_BATTERY_TEMP);
 	if (ret < 0)
@@ -543,7 +573,7 @@
 
 	/*calculating temperature*/
 	for (temp = 58; temp >= 0; temp--) {
-		int actual = therm_tbl[temp];
+		int actual = di->pdata->battery_tmp_tbl[temp];
 		if ((actual - res) >= 0)
 			break;
 	}
@@ -661,6 +691,9 @@
 		return ret;
 	}
 
+#ifdef DEBUG
+	printk("BCI DEBUG: BCIMSTATEC Charge state is 0x%x\n", status);
+#endif
 	return (int) (status & BCIMSTAT_MASK);
 }
 
@@ -709,14 +742,43 @@
  */
 static int twl4030battery_temp_setup(void)
 {
-	int ret;
+#ifdef DEBUG
+	u8 i;
+#endif
+	u8 ret;
 
 	/* Enabling thermistor current */
-	ret = clear_n_set(TWL4030_MODULE_MAIN_CHARGE, 0, ITHEN,
+	ret = clear_n_set(TWL4030_MODULE_MAIN_CHARGE, 0, 0x1B,
 		REG_BCICTL1);
 	if (ret)
 		return ret;
 
+#ifdef DEBUG
+	twl4030_i2c_read_u8(TWL4030_MODULE_PM_MASTER, &ret, REG_BOOT_BCI);
+	printk("BCI DEBUG: BOOT_BCI Value is 0x%x\n", ret);
+
+	twl4030_i2c_read_u8(TWL4030_MODULE_PM_MASTER, &ret, REG_STS_HW_CONDITIONS);
+	printk("BCI DEBUG: STS_HW_CONDITIONS Value is 0x%x\n", ret);
+
+	twl4030_i2c_read_u8(TWL4030_MODULE_MAIN_CHARGE, &ret, REG_BCICTL1);
+	printk("BCI DEBUG: BCICTL1 Value is 0x%x\n", ret);
+
+	twl4030_i2c_read_u8(TWL4030_MODULE_MAIN_CHARGE, &ret, REG_BCICTL2);
+	printk("BCI DEBUG: BCICTL2 Value is 0x%x\n", ret);
+
+	twl4030_i2c_read_u8(TWL4030_MODULE_MAIN_CHARGE, &ret, 0x0);
+	printk("BCI DEBUG: BCIMDEN Value is 0x%x\n", ret);
+
+	twl4030_i2c_read_u8(TWL4030_MODULE_INTBR, &ret, REG_GPBR1);
+	printk("BCI DEBUG: GPBR1 Value is 0x%x\n", ret);
+
+	for(i = 0x0; i <= 0x32; i++)
+	{
+		twl4030_i2c_read_u8(TWL4030_MODULE_MAIN_CHARGE, &ret, i);
+		printk("BCI DEBUG: BCI 0x%x Value is 0x%x\n", i, ret);
+	}
+#endif
+
 	return 0;
 }
 
@@ -732,7 +794,6 @@
 	ret = twl4030_i2c_read_u8(mod_no, &val, reg);
 	if (ret)
 		return ret;
-
 	/* Clearing all those bits to clear */
 	val &= ~(clear);
 
@@ -772,13 +833,14 @@
 		struct twl4030_bci_device_info,
 		twl4030_bk_bci_monitor_work.work);
 
-	twl4030_bk_bci_battery_read_status(di);
+	if(!di->pdata->no_backup_battery)
+		twl4030_bk_bci_battery_read_status(di);
 	schedule_delayed_work(&di->twl4030_bk_bci_monitor_work, 500);
 }
 
 static void twl4030_bci_battery_read_status(struct twl4030_bci_device_info *di)
 {
-	di->temp_C = twl4030battery_temperature();
+	di->temp_C = twl4030battery_temperature(di);
 	di->voltage_uV = twl4030battery_voltage();
 	di->current_uA = twl4030battery_current();
 }
@@ -819,6 +881,87 @@
 #define to_twl4030_bk_bci_device_info(x) container_of((x), \
 		struct twl4030_bci_device_info, bk_bat);
 
+static ssize_t
+show_charge_current(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	u8  ctl;
+	int ret = read_bci_val(REG_BCIIREF1) & 0x1FF;
+	twl4030_i2c_read_u8(TWL4030_MODULE_MAIN_CHARGE, &ctl, REG_BCICTL1);
+
+	if (ctl & CGAIN)
+		ret |= 0x200;
+
+#ifdef DEBUG
+	/* Dump debug */
+	twl4030battery_temp_setup();
+#endif
+
+	return sprintf(buf, "%d\n", ret);
+}
+
+static ssize_t
+set_charge_current(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
+{
+	unsigned long newCurrent;
+	int ret;
+
+	ret = strict_strtoul(buf, 10, &newCurrent);
+	if (ret)
+		return -EINVAL;
+
+	ret = twl4030_i2c_write_u8(TWL4030_MODULE_MAIN_CHARGE, KEY_IIREF, REG_BCIMFKEY);
+	if (ret)
+		return ret;
+
+	ret = twl4030_i2c_write_u8(TWL4030_MODULE_MAIN_CHARGE, newCurrent & 0xff, REG_BCIIREF1);
+	if (ret)
+		return ret;
+
+	ret = twl4030_i2c_write_u8(TWL4030_MODULE_MAIN_CHARGE, KEY_IIREF, REG_BCIMFKEY);
+	if (ret)
+		return ret;
+
+	ret = twl4030_i2c_write_u8(TWL4030_MODULE_MAIN_CHARGE, (newCurrent >> 8) & 0x1, REG_BCIIREF2);
+	if (ret)
+		return ret;
+
+	/* Set software-controlled charge */
+	twl4030charger_ac_en(ENABLE, 0);
+
+	/* Set CGAIN = 0 or 1 */
+	if(newCurrent > 511) {
+		u8 tmp;
+
+		/* Set CGAIN = 1 -- need to wait until automatic charge turns off */
+		while(!ret) {
+			clear_n_set(TWL4030_MODULE_MAIN_CHARGE, 0, CGAIN | 0x1B, REG_BCICTL1);
+			twl4030_i2c_read_u8(TWL4030_MODULE_MAIN_CHARGE, &tmp, REG_BCICTL1);
+
+			ret = tmp & CGAIN;
+			if(!ret)
+				mdelay(50);
+		}
+	} else {
+		u8 tmp;
+
+		/* Set CGAIN = 0 -- need to wait until automatic charge turns off */
+		while(!ret) {
+			clear_n_set(TWL4030_MODULE_MAIN_CHARGE, CGAIN, 0x1B, REG_BCICTL1);
+			twl4030_i2c_read_u8(TWL4030_MODULE_MAIN_CHARGE, &tmp, REG_BCICTL1);
+
+			ret = !(tmp & CGAIN);
+			if(!ret)
+				mdelay(50);
+		}
+	}
+
+	/* Set automatic charge (CGAIN = 0/1 persists) */
+	twl4030charger_ac_en(ENABLE, 1);
+
+	return count;
+}
+static DEVICE_ATTR(charge_current, S_IRUGO | S_IWUSR, show_charge_current, set_charge_current);
+
 static int twl4030_bk_bci_battery_get_property(struct power_supply *psy,
 					enum power_supply_property psp,
 					union power_supply_propval *val)
@@ -912,8 +1055,6 @@
 	int irq;
 	int ret;
 
-	therm_tbl = pdata->battery_tmp_tbl;
-
 	di = kzalloc(sizeof(*di), GFP_KERNEL);
 	if (!di)
 		return -ENOMEM;
@@ -937,8 +1078,12 @@
 	di->bk_bat.num_properties = ARRAY_SIZE(twl4030_bk_bci_battery_props);
 	di->bk_bat.get_property = twl4030_bk_bci_battery_get_property;
 	di->bk_bat.external_power_changed = NULL;
+	di->pdata = pdata;
 
-	twl4030charger_ac_en(ENABLE);
+	/* Set up clocks */
+	twl4030_i2c_write_u8(TWL4030_MODULE_INTBR, MADC_HFCLK_EN | DEFAULT_MADC_CLK_EN, REG_GPBR1);
+
+	twl4030charger_ac_en(ENABLE, CHARGE_MODE);
 	twl4030charger_usb_en(ENABLE);
 	twl4030battery_hw_level_en(ENABLE);
 	twl4030battery_hw_presence_en(ENABLE);
@@ -951,9 +1096,12 @@
 		goto temp_setup_fail;
 
 	/* enabling GPCH09 for read back battery voltage */
-	ret = twl4030backupbatt_voltage_setup();
-	if (ret)
-		goto voltage_setup_fail;
+	if(!di->pdata->no_backup_battery)
+	{
+		ret = twl4030backupbatt_voltage_setup();
+		if (ret)
+			goto voltage_setup_fail;
+	}
 
 	/* REVISIT do we need to request both IRQs ?? */
 
@@ -988,9 +1136,18 @@
 				twl4030_bci_battery_work);
 	schedule_delayed_work(&di->twl4030_bci_monitor_work, 0);
 
-	ret = power_supply_register(&pdev->dev, &di->bk_bat);
+	if(!pdata->no_backup_battery)
+	{
+		ret = power_supply_register(&pdev->dev, &di->bk_bat);
+		if (ret) {
+			dev_dbg(&pdev->dev, "failed to register backup battery\n");
+			goto bk_batt_failed;
+		}
+	}
+
+	ret = device_create_file(di->bat.dev, &dev_attr_charge_current);
 	if (ret) {
-		dev_dbg(&pdev->dev, "failed to register backup battery\n");
+		dev_err(&pdev->dev, "failed to create sysfs entries\n");
 		goto bk_batt_failed;
 	}
 
@@ -1001,7 +1158,8 @@
 	return 0;
 
 bk_batt_failed:
-	power_supply_unregister(&di->bat);
+	if(!pdata->no_backup_battery)
+		power_supply_unregister(&di->bat);
 batt_failed:
 	free_irq(irq, di);
 chg_irq_fail:
@@ -1010,7 +1168,7 @@
 batt_irq_fail:
 voltage_setup_fail:
 temp_setup_fail:
-	twl4030charger_ac_en(DISABLE);
+	twl4030charger_ac_en(DISABLE, CHARGE_MODE);
 	twl4030charger_usb_en(DISABLE);
 	twl4030battery_hw_level_en(DISABLE);
 	twl4030battery_hw_presence_en(DISABLE);
@@ -1024,7 +1182,7 @@
 	struct twl4030_bci_device_info *di = platform_get_drvdata(pdev);
 	int irq;
 
-	twl4030charger_ac_en(DISABLE);
+	twl4030charger_ac_en(DISABLE, CHARGE_MODE);
 	twl4030charger_usb_en(DISABLE);
 	twl4030battery_hw_level_en(DISABLE);
 	twl4030battery_hw_presence_en(DISABLE);
--- a/include/linux/i2c/twl4030.h
+++ b/include/linux/i2c/twl4030.h
@@ -299,6 +299,8 @@ int twl4030_i2c_read(u8 mod_no, u8 *value, u8 reg, unsigned num_bytes);
 struct twl4030_bci_platform_data {
 	int *battery_tmp_tbl;
 	unsigned int tblsize;
+
+	bool no_backup_battery;
 };
 
 /* TWL4030_GPIO_MAX (18) GPIOs, with interrupts */