max17042: Add POR init procedure from Maxim appnote

Add power on reset (POR) init procedure defined by the maxim
appnote. Using this procedure ensures that the part is
configured/initialized correctly at POR and improves early accuracy of
the fuel gauge and informs the fuel gauge with the battery
characterization parameters.  The battery characterization parameters
come from the maxim characterization procedure.

Signed-off-by: Ramakrishna Pallala <ramakrishna.pallala@intel.com>
Signed-off-by: Dirk Brandewie <dirk.brandewie@gmail.com>
Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
diff --git a/include/linux/power/max17042_battery.h b/include/linux/power/max17042_battery.h
index 67eeada..e01b167 100644
--- a/include/linux/power/max17042_battery.h
+++ b/include/linux/power/max17042_battery.h
@@ -27,6 +27,8 @@
 #define MAX17042_BATTERY_FULL	(100)
 #define MAX17042_DEFAULT_SNS_RESISTOR	(10000)
 
+#define MAX17042_CHARACTERIZATION_DATA_SIZE 48
+
 enum max17042_register {
 	MAX17042_STATUS		= 0x00,
 	MAX17042_VALRT_Th	= 0x01,
@@ -124,10 +126,64 @@
 	u16 data;
 };
 
+struct max17042_config_data {
+	/* External current sense resistor value in milli-ohms */
+	u32	cur_sense_val;
+
+	/* A/D measurement */
+	u16	tgain;		/* 0x2C */
+	u16	toff;		/* 0x2D */
+	u16	cgain;		/* 0x2E */
+	u16	coff;		/* 0x2F */
+
+	/* Alert / Status */
+	u16	valrt_thresh;	/* 0x01 */
+	u16	talrt_thresh;	/* 0x02 */
+	u16	soc_alrt_thresh;	/* 0x03 */
+	u16	config;		/* 0x01D */
+	u16	shdntimer;	/* 0x03F */
+
+	/* App data */
+	u16	design_cap;	/* 0x18 */
+	u16	ichgt_term;	/* 0x1E */
+
+	/* MG3 config */
+	u16	at_rate;	/* 0x04 */
+	u16	learn_cfg;	/* 0x28 */
+	u16	filter_cfg;	/* 0x29 */
+	u16	relax_cfg;	/* 0x2A */
+	u16	misc_cfg;	/* 0x2B */
+	u16	masksoc;	/* 0x32 */
+
+	/* MG3 save and restore */
+	u16	fullcap;	/* 0x10 */
+	u16	fullcapnom;	/* 0x23 */
+	u16	socempty;	/* 0x33 */
+	u16	lavg_empty;	/* 0x36 */
+	u16	dqacc;		/* 0x45 */
+	u16	dpacc;		/* 0x46 */
+
+	/* Cell technology from power_supply.h */
+	u16	cell_technology;
+
+	/* Cell Data */
+	u16	vempty;		/* 0x12 */
+	u16	temp_nom;	/* 0x24 */
+	u16	temp_lim;	/* 0x25 */
+	u16	fctc;		/* 0x37 */
+	u16	rcomp0;		/* 0x38 */
+	u16	tcompc0;	/* 0x39 */
+	u16	empty_tempco;	/* 0x3A */
+	u16	kempty0;	/* 0x3B */
+	u16	cell_char_tbl[MAX17042_CHARACTERIZATION_DATA_SIZE];
+} __packed;
+
 struct max17042_platform_data {
 	struct max17042_reg_data *init_data;
+	struct max17042_config_data *config_data;
 	int num_init_data; /* Number of enties in init_data array */
 	bool enable_current_sense;
+	bool enable_por_init; /* Use POR init from Maxim appnote */
 
 	/*
 	 * R_sns in micro-ohms.