MFD: TWL 6030: Add VLOW interrupt handler to shutdown device

This change adds an interrupt handler to shutdown device when
battery voltage drops below TWL 6030 threshold VBATMIN_HI.

Change-Id: I6556fd213ab0fafa9ae78c37c1a4672d1440c304
Signed-off-by: Danke Xie <d.xie@sta.samsung.com>

3 files changed, 106 insertions, 2 deletions

diff --git a/drivers/mfd/twl-core.c b/drivers/mfd/twl-core.c
index 194a674..ed11f61 100644
--- a/drivers/mfd/twl-core.c
+++ b/drivers/mfd/twl-core.c
@@ -126,6 +126,7 @@
 
 /* Last - for index max*/
 #define TWL4030_MODULE_LAST		TWL4030_MODULE_SECURED_REG
+#define TWL6030_MODULE_LAST		TWL6030_MODULE_SLAVE_RES
 
 #define TWL_NUM_SLAVES		4
 
@@ -141,7 +142,7 @@
 #define SUB_CHIP_ID2 2
 #define SUB_CHIP_ID3 3
 
-#define TWL_MODULE_LAST TWL4030_MODULE_LAST
+#define TWL_MODULE_LAST TWL6030_MODULE_LAST
 
 /* Base Address defns for twl4030_map[] */
 
@@ -187,6 +188,7 @@
 #define TWL6030_BASEADD_MEM		0x0017
 #define TWL6030_BASEADD_PM_MASTER	0x001F
 #define TWL6030_BASEADD_PM_SLAVE_MISC	0x0030 /* PM_RECEIVER */
+#define TWL6030_BASEADD_PM_SLAVE_RES	0x00AD
 #define TWL6030_BASEADD_PM_MISC		0x00E2
 #define TWL6030_BASEADD_PM_PUPD		0x00F0
 
@@ -333,6 +335,7 @@ static struct twl_mapping twl6030_map[] = {
 	{ SUB_CHIP_ID0, TWL6030_BASEADD_RTC },
 	{ SUB_CHIP_ID0, TWL6030_BASEADD_MEM },
 	{ SUB_CHIP_ID1, TWL6025_BASEADD_CHARGER },
+	{ SUB_CHIP_ID0, TWL6030_BASEADD_PM_SLAVE_RES },
 };
 
 /*----------------------------------------------------------------------*/
diff --git a/drivers/mfd/twl6030-irq.c b/drivers/mfd/twl6030-irq.c
index 7999d3f..67fb7ff 100644
--- a/drivers/mfd/twl6030-irq.c
+++ b/drivers/mfd/twl6030-irq.c
@@ -38,6 +38,7 @@
 #include <linux/i2c/twl.h>
 #include <linux/platform_device.h>
 #include <linux/suspend.h>
+#include <linux/reboot.h>
 
 #include "twl-core.h"
 
@@ -56,7 +57,7 @@
 static int twl6030_interrupt_mapping[24] = {
 	PWR_INTR_OFFSET,	/* Bit 0	PWRON			*/
 	PWR_INTR_OFFSET,	/* Bit 1	RPWRON			*/
-	PWR_INTR_OFFSET,	/* Bit 2	BAT_VLOW		*/
+	TWL_VLOW_INTR_OFFSET,	/* Bit 2	BAT_VLOW		*/
 	RTC_INTR_OFFSET,	/* Bit 3	RTC_ALARM		*/
 	RTC_INTR_OFFSET,	/* Bit 4	RTC_PERIOD		*/
 	HOTDIE_INTR_OFFSET,	/* Bit 5	HOT_DIE			*/
@@ -216,6 +217,17 @@ static irqreturn_t handle_twl6030_pih(int irq, void *devid)
 	return IRQ_HANDLED;
 }
 
+/*
+ * handle_twl6030_vlow() is a threaded BAT_VLOW interrupt handler. BAT_VLOW
+ * is a secondary interrupt generated in twl6030_irq_thread().
+ */
+static irqreturn_t handle_twl6030_vlow(int irq, void *unused)
+{
+	pr_info("handle_twl6030_vlow: kernel_power_off()\n");
+	kernel_power_off();
+	return IRQ_HANDLED;
+}
+
 /*----------------------------------------------------------------------*/
 
 static inline void activate_irq(int irq)
@@ -344,6 +356,70 @@ int twl6030_mmc_card_detect(struct device *dev, int slot)
 }
 EXPORT_SYMBOL(twl6030_mmc_card_detect);
 
+int twl6030_vlow_init(int vlow_irq)
+{
+	int status;
+	u8 val;
+
+	status = twl_i2c_read_u8(TWL_MODULE_PM_SLAVE_RES, &val,
+			REG_VBATMIN_HI_CFG_STATE);
+	if (status < 0) {
+		pr_err("twl6030: I2C err reading REG_VBATMIN_HI_CFG_STATE: %d\n",
+				status);
+		return status;
+	}
+
+	status = twl_i2c_write_u8(TWL_MODULE_PM_SLAVE_RES,
+			val | VBATMIN_VLOW_EN, REG_VBATMIN_HI_CFG_STATE);
+	if (status < 0) {
+		pr_err("twl6030: I2C err writing REG_VBATMIN_HI_CFG_STATE: %d\n",
+				status);
+		return status;
+	}
+
+	status = twl_i2c_read_u8(TWL_MODULE_PIH, &val, REG_INT_MSK_LINE_A);
+	if (status < 0) {
+		pr_err("twl6030: I2C err reading REG_INT_MSK_LINE_A: %d\n",
+				status);
+		return status;
+	}
+
+	status = twl_i2c_write_u8(TWL_MODULE_PIH, val & ~VLOW_INT_MASK,
+			REG_INT_MSK_LINE_A);
+	if (status < 0) {
+		pr_err("twl6030: I2C err writing REG_INT_MSK_LINE_A: %d\n",
+				status);
+		return status;
+	}
+
+	status = twl_i2c_read_u8(TWL_MODULE_PIH, &val, REG_INT_MSK_STS_A);
+	if (status < 0) {
+		pr_err("twl6030: I2C err reading REG_INT_MSK_STS_A: %d\n",
+				status);
+		return status;
+	}
+
+	status = twl_i2c_write_u8(TWL_MODULE_PIH, val & ~VLOW_INT_MASK,
+		REG_INT_MSK_STS_A);
+	if (status < 0) {
+		pr_err("twl6030: I2C err writing REG_INT_MSK_STS_A: %d\n",
+				status);
+		return status;
+	}
+
+	/* install an irq handler for vlow */
+	status = request_threaded_irq(vlow_irq, NULL, handle_twl6030_vlow,
+			IRQF_ONESHOT,
+			"TWL6030-VLOW", handle_twl6030_vlow);
+	if (status < 0) {
+		pr_err("twl6030: could not claim vlow irq %d: %d\n", vlow_irq,
+				status);
+		return status;
+	}
+
+	return 0;
+}
+
 int twl6030_init_irq(int irq_num, unsigned irq_base, unsigned irq_end)
 {
 
@@ -403,7 +479,16 @@ int twl6030_init_irq(int irq_num, unsigned irq_base, unsigned irq_end)
 
 	twl_irq = irq_num;
 	register_pm_notifier(&twl6030_irq_pm_notifier_block);
+
+	status = twl6030_vlow_init(twl6030_irq_base + TWL_VLOW_INTR_OFFSET);
+	if (status < 0)
+		goto fail_vlow;
+
 	return status;
+
+fail_vlow:
+	free_irq(irq_num, &irq_event);
+
 fail_irq:
 	free_irq(irq_num, &irq_event);
 
@@ -426,6 +511,9 @@ int twl6030_exit_irq(void)
 		return -ENOSYS;
 	}
 
+	free_irq(twl6030_irq_base + TWL_VLOW_INTR_OFFSET,
+		handle_twl6030_vlow);
+
 	free_irq(twl_irq, &irq_event);
 
 	for (i = twl6030_irq_base; i < twl6030_irq_end; i++)
diff --git a/include/linux/i2c/twl.h b/include/linux/i2c/twl.h
index a9bfb2a..a163c7d 100644
--- a/include/linux/i2c/twl.h
+++ b/include/linux/i2c/twl.h
@@ -71,6 +71,7 @@
 #define TWL4030_MODULE_PM_RECEIVER	0x15
 #define TWL4030_MODULE_RTC		0x16
 #define TWL4030_MODULE_SECURED_REG	0x17
+#define TWL6030_MODULE_SLAVE_RES	0x19
 
 #define TWL_MODULE_USB		TWL4030_MODULE_USB
 #define TWL_MODULE_AUDIO_VOICE	TWL4030_MODULE_AUDIO_VOICE
@@ -81,6 +82,7 @@
 #define TWL_MODULE_PM_RECEIVER	TWL4030_MODULE_PM_RECEIVER
 #define TWL_MODULE_RTC		TWL4030_MODULE_RTC
 #define TWL_MODULE_PWM		TWL4030_MODULE_PWM0
+#define TWL_MODULE_PM_SLAVE_RES	TWL6030_MODULE_SLAVE_RES
 
 #define TWL6030_MODULE_ID0	0x0D
 #define TWL6030_MODULE_ID1	0x0E
@@ -100,6 +102,7 @@
  * Offset from TWL6030_IRQ_BASE / pdata->irq_base
  */
 #define PWR_INTR_OFFSET		0
+#define TWL_VLOW_INTR_OFFSET	6
 #define HOTDIE_INTR_OFFSET	12
 #define SMPSLDO_INTR_OFFSET	13
 #define BATDETECT_INTR_OFFSET	14
@@ -151,6 +154,8 @@
 #define MMC_PU				(0x1 << 3)
 #define MMC_PD				(0x1 << 2)
 
+#define VLOW_INT_MASK			(0x1 << 2)
+
 #define TWL_SIL_TYPE(rev)		((rev) & 0x00FFFFFF)
 #define TWL_SIL_REV(rev)		((rev) >> 24)
 #define TWL_SIL_5030			0x09002F
@@ -450,6 +455,14 @@ static inline int twl6030_mmc_card_detect(struct device *dev, int slot)
 
 #define TWL4030_PM_MASTER_GLOBAL_TST		0xb6
 
+/*
+ * PM Slave resource module register offsets (use TWL6030_MODULE_SLAVE_RES)
+ */
+
+#define REG_VBATMIN_HI_CFG_STATE		0x1D
+
+#define VBATMIN_VLOW_EN				0x21
+
 /*----------------------------------------------------------------------*/
 
 /* Power bus message definitions */