[U-Boot] [PATCH 1/4 v2] PMIC: max77686: add pmic_set_voltage api for max77686

[Akshay Saraswat]

This patch adds pmic_set_voltage api in max77686.
As the name suggests, this api is required for switching
voltage from one level to another. Unit for the new
voltage value should be microvolts.

Signed-off-by: Akshay Saraswat <akshay.s at samsung.com>
---
Changes since v1:
	- Added comment for the set voltage API.

 drivers/power/pmic/pmic_max77686.c |   66 ++++++++++++++++++++++++++++++++++++
 include/power/max77686_pmic.h      |   12 +++++++
 include/power/pmic.h               |    1 +
 3 files changed, 79 insertions(+)

diff --git a/drivers/power/pmic/pmic_max77686.c b/drivers/power/pmic/pmic_max77686.c
index 7fcb4c0..9e1bfdb 100644
--- a/drivers/power/pmic/pmic_max77686.c
+++ b/drivers/power/pmic/pmic_max77686.c
@@ -77,3 +77,69 @@ int pmic_init(unsigned char bus)
 
 	return 0;
 }
+/*
+ * Change voltage in BUCK2 to the new value given.
+ *
+ * @param new_voltage		new volatge value (unit - microvolts)
+ * @return			int value, 0 for success
+ */
+int pmic_set_voltage(u32 new_voltage)
+{
+	struct pmic *p;
+	u32 read_data, volt_level, ret;
+
+	p = pmic_get("MAX77686_PMIC");
+	if (!p)
+		return -ENODEV;
+
+	/* Read BUCK2 DVS1 value */
+	ret = pmic_reg_read(p, MAX77686_REG_PMIC_BUCK2DVS1, &read_data);
+	if (ret != 0) {
+		debug("CPUFREQ: max77686 BUCK2 DVS1 register read failed.\n");
+		return -1;
+	}
+
+	/* Calculate voltage level */
+	volt_level = new_voltage - MAX77686_BUCK2_VOL_MIN * 1000;
+
+	if (volt_level < 0) {
+		debug("CPUFREQ: Not a valid voltage level to set\n");
+		return -1;
+	}
+
+	volt_level /= MAX77686_BUCK2_VOL_DIV;
+
+	/* Update voltage level in BUCK2 DVS1 register value */
+	clrsetbits_8(&read_data,
+		     MAX77686_BUCK2_VOL_BITMASK << MAX77686_BUCK2_VOL_BITPOS,
+		     volt_level << MAX77686_BUCK2_VOL_BITPOS);
+
+	/* Write new value in BUCK2 DVS1 */
+	ret = pmic_reg_write(p, MAX77686_REG_PMIC_BUCK2DVS1, read_data);
+	if (ret != 0) {
+		debug("CPUFREQ: max77686 BUCK2 DVS1 register write failed.\n");
+		return -1;
+	}
+
+	/* Set ENABLE BUCK2 register bits */
+	read_data = 0;
+	ret = pmic_reg_read(p, MAX77686_BUCK2_VOL_ENADDR, &read_data);
+	if (ret != 0) {
+		debug("CPUFREQ: max77686 BUCK2 enable address read failed.\n");
+		return -1;
+	}
+
+	clrsetbits_8(&read_data,
+		     (MAX77686_BUCK2_VOL_ENBITMASK
+		     << MAX77686_BUCK2_VOL_ENBITPOS),
+		     (MAX77686_BUCK2_VOL_ENBITON
+		     << MAX77686_BUCK2_VOL_ENBITPOS));
+
+	ret = pmic_reg_write(p, MAX77686_BUCK2_VOL_ENADDR, read_data);
+	if (ret != 0) {
+		debug("CPUFREQ: max77686 BUCK2 enable address write failed.\n");
+		return -1;
+	}
+
+	return 0;
+}
diff --git a/include/power/max77686_pmic.h b/include/power/max77686_pmic.h
index fdc7ca9..2780f17 100644
--- a/include/power/max77686_pmic.h
+++ b/include/power/max77686_pmic.h
@@ -175,6 +175,18 @@ enum {
 #define MAX77686_LD05CTRL1_1_8V	0x14
 /* LDO10 1.8 volt value */
 #define MAX77686_LD10CTRL1_1_8V	0x14
+
+/* BUCK2 voltage parameter values */
+#define MAX77686_BUCK2_VOL_BITPOS	0x0
+#define MAX77686_BUCK2_VOL_BITMASK	0xff
+#define MAX77686_BUCK2_VOL_ENBITPOS	0x4
+#define MAX77686_BUCK2_VOL_ENBITMASK	0x3
+#define MAX77686_BUCK2_VOL_ENADDR	0x12
+#define MAX77686_BUCK2_VOL_ENBITON	0x1
+#define MAX77686_BUCK2_VOL_ENBITOFF	0x0
+#define MAX77686_BUCK2_VOL_MIN		925
+#define MAX77686_BUCK2_VOL_DIV		12500
+
 /*
  * MAX77686_REG_PMIC_32KHZ set to 32KH CP
  * output is activated
diff --git a/include/power/pmic.h b/include/power/pmic.h
index 1ecfc05..02f6f11 100644
--- a/include/power/pmic.h
+++ b/include/power/pmic.h
@@ -99,6 +99,7 @@ int pmic_probe(struct pmic *p);
 int pmic_reg_read(struct pmic *p, u32 reg, u32 *val);
 int pmic_reg_write(struct pmic *p, u32 reg, u32 val);
 int pmic_set_output(struct pmic *p, u32 reg, int ldo, int on);
+int pmic_set_voltage(u32 new_voltage);
 
 #define pmic_i2c_addr (p->hw.i2c.addr)
 #define pmic_i2c_tx_num (p->hw.i2c.tx_num)
-- 
1.7.10.4