pmic: tps65218: add useful functions and defines

Add the following functions:
tps65218_reg_read() for accessing redisters
tps65218_toggle_fseal() for toggling the fseal bit
tps65218_lock_fsea() for locking the fseal bit to 1

Add the following defines:
All status register bits

Cc: Tom Rini <trini@konsulko.com>
Cc: Albert Aribaud <albert.u.boot@aribaud.net>
Cc: Igor Grinberg <grinberg@compulab.co.il>
Signed-off-by: Nikita Kiryanov <nikita@compulab.co.il>
Reviewed-by: Tom Rini <trini@konsulko.com>

drivers/power/pmic/pmic_tps65218.c

@@ -11,6 +11,20 @@
 #include <power/pmic.h>
 #include <power/tps65218.h>
 
+int tps65218_reg_read(uchar dest_reg, uchar *dest_val)
+{
+	uchar read_val;
+	int ret;
+
+	ret = i2c_read(TPS65218_CHIP_PM, dest_reg, 1, &read_val, 1);
+	if (ret)
+		return ret;
+
+	*dest_val = read_val;
+
+	return 0;
+}
+
 /**
  *  tps65218_reg_write() - Generic function that can write a TPS65218 PMIC
  *			   register or bit field regardless of protection
@@ -98,6 +112,48 @@ int tps65218_voltage_update(uchar dc_cntrl_reg, uchar volt_sel)
 	return 0;
 }
 
+/**
+ * tps65218_toggle_fseal() - Perform the sequence that toggles the FSEAL bit.
+ *
+ * @return:		     0 on success, -EBADE if the sequence was broken
+ */
+int tps65218_toggle_fseal(void)
+{
+	if (tps65218_reg_write(TPS65218_PROT_LEVEL_NONE, TPS65218_PASSWORD,
+			       0xb1, TPS65218_MASK_ALL_BITS))
+		return -EBADE;
+
+	if (tps65218_reg_write(TPS65218_PROT_LEVEL_NONE, TPS65218_PASSWORD,
+			       0xfe, TPS65218_MASK_ALL_BITS))
+		return -EBADE;
+
+	if (tps65218_reg_write(TPS65218_PROT_LEVEL_NONE, TPS65218_PASSWORD,
+			       0xa3, TPS65218_MASK_ALL_BITS))
+		return -EBADE;
+
+	return 0;
+}
+
+/**
+ * tps65218_lock_fseal() - Perform the sequence that locks the FSEAL bit to 1.
+ *
+ * The FSEAL bit prevents the PMIC from turning off DCDC5 and DCDC6. It can be
+ * toggled at most 3 times: 0->1, 1->0, and finally 0->1. After the third switch
+ * its value is locked and can only be reset by powering off the PMIC entirely.
+ *
+ * @return:		   0 on success, -EBADE if the sequence was broken
+ */
+int tps65218_lock_fseal(void)
+{
+	int i;
+
+	for (i = 0; i < 3; i++)
+		if (tps65218_toggle_fseal())
+			return -EBADE;
+
+	return 0;
+}
+
 int power_tps65218_init(unsigned char bus)
 {
 	static const char name[] = "TPS65218_PMIC";

include/power/tps65218.h

@@ -8,6 +8,8 @@
 #ifndef __POWER_TPS65218_H__
 #define __POWER_TPS65218_H__
 
+#include <linux/bitops.h>
+
 /* I2C chip address */
 #define TPS65218_CHIP_PM			0x24
 
@@ -60,8 +62,18 @@ enum {
 #define TPS65218_DCDC_VOLT_SEL_1260MV		0x29
 #define TPS65218_DCDC_VOLT_SEL_1330MV		0x30
 
+#define TPS65218_CC_STAT	(BIT(0) | BIT(1))
+#define TPS65218_STATE		(BIT(2) | BIT(3))
+#define TPS65218_PB_STATE	BIT(4)
+#define TPS65218_AC_STATE	BIT(5)
+#define TPS65218_EE		BIT(6)
+#define TPS65218_FSEAL		BIT(7)
+
+int tps65218_reg_read(uchar dest_reg, uchar *dest_val);
 int tps65218_reg_write(uchar prot_level, uchar dest_reg, uchar dest_val,
 		       uchar mask);
 int tps65218_voltage_update(uchar dc_cntrl_reg, uchar volt_sel);
+int tps65218_toggle_fseal(void);
+int tps65218_lock_fseal(void);
 int power_tps65218_init(unsigned char bus);
 #endif	/* __POWER_TPS65218_H__ */