mfd/power: axp20x-usb-power driver

From: Bruno Pr?mont <[email protected]>

Add an extra set of registers which is necessary tu support the PMICs battery charger function, and mark registers which contain status bits, gpio status, and adc readings as volatile.

Cc Bruno Pr?mont <[email protected]>

Signed-off-by Hans de Goede <[email protected]>

---
Changes in v2:
-Add a AXP20X_OCV_MAX define

---
 drivers/mfd/axp20x.c       | 8 +++++++-
 include/linux/mfd/axp20x.h | 6 ++++++
 2 files changed, 13 insertions(+), 1 deletion(-)

drivers/mfd/axp20x.c +7 -1

index 6df9155..f9a3c2d 100644
@@ -39,10 +39,16 @@ static const char * const axp20x_model_names[] = {
 static const struct regmap_range axp20x_writeable_ranges[] = {
 	regmap_reg_range(AXP20X_DATACACHE(0), AXP20X_IRQ5_STATE),
 	regmap_reg_range(AXP20X_DCDC_MODE, AXP20X_FG_RES),
+	regmap_reg_range(AXP20X_RDC_H, AXP20X_OCV(15)),
 };
 
 static const struct regmap_range axp20x_volatile_ranges[] = {
+	regmap_reg_range(AXP20X_PWR_INPUT_STATUS, AXP20X_USB_OTG_STATUS),
+	regmap_reg_range(AXP20X_CHRG_CTRL1, AXP20X_CHRG_CTRL2),
 	regmap_reg_range(AXP20X_IRQ1_EN, AXP20X_IRQ5_STATE),
+	regmap_reg_range(AXP20X_ACIN_V_ADC_H, AXP20X_IPSOUT_V_HIGH_L),
+	regmap_reg_range(AXP20X_GPIO20_SS, AXP20X_GPIO3_CTRL),
+	regmap_reg_range(AXP20X_FG_RES, AXP20X_RDC_L),
 };
 
 static const struct regmap_access_table axp20x_writeable_table = {

@@ -159,7 +165,7 @@ static const struct regmap_config axp20x_regmap_config = {
 	.val_bits	= 8,
 	.wr_table	= &axp20x_writeable_table,
 	.volatile_table	= &axp20x_volatile_table,
-	.max_register	= AXP20X_FG_RES,
+	.max_register	= AXP20X_OCV(AXP20X_OCV_MAX),
 	.cache_type	= REGCACHE_RBTREE,
 };
 

include/linux/mfd/axp20x.h +6 -0

index 5275423..6d8b39a 100644
@@ -151,6 +151,12 @@ enum {
 #define AXP20X_CC_CTRL			0xb8
 #define AXP20X_FG_RES			0xb9
 
+/* OCV */
+#define AXP20X_RDC_H			0xba
+#define AXP20X_RDC_L			0xbb
+#define AXP20X_OCV(m)			(0xc0 + (m))
+#define AXP20X_OCV_MAX			0xf
+
 /* AXP22X specific registers */
 #define AXP22X_BATLOW_THRES1		0xe6
 

Add a cell for the usb power_supply part of the axp20x PMICs.

Note that this cell is only for the usb power_supply part and not the ac-power / battery-charger / rtc-backup-bat-charger bits.

Depending on the board each of those must be enabled / disabled separately in devicetree as most boards do not use all 4. So in dt each one needs its own child-node of the axp20x node. Another reason for using separate child nodes for each is so that other devicetree nodes can have a power-supply property with a phandle referencing a node representing a single power-supply.

The decision to use a separate devicetree node for each is reflected on the kernel side by each getting its own mfd-cell / platform_device and platform-driver.

drivers/mfd/axp20x.c +16 -4

index f9a3c2d..ca4a604 100644
@@ -113,6 +113,13 @@ static struct resource axp20x_pek_resources[] = {
 	},
 };
 
+static struct resource axp20x_usb_power_supply_resources[] = {
+	DEFINE_RES_IRQ_NAMED(AXP20X_IRQ_VBUS_PLUGIN, "VBUS_PLUGIN"),
+	DEFINE_RES_IRQ_NAMED(AXP20X_IRQ_VBUS_REMOVAL, "VBUS_REMOVAL"),
+	DEFINE_RES_IRQ_NAMED(AXP20X_IRQ_VBUS_VALID, "VBUS_VALID"),
+	DEFINE_RES_IRQ_NAMED(AXP20X_IRQ_VBUS_NOT_VALID, "VBUS_NOT_VALID"),
+};
+
 static struct resource axp22x_pek_resources[] = {
 	{
 		.name   = "PEK_DBR",

@@ -363,11 +370,16 @@ static const struct regmap_irq_chip axp288_regmap_irq_chip = {
 
 static struct mfd_cell axp20x_cells[] = {
 	{
-		.name			= "axp20x-pek",
-		.num_resources		= ARRAY_SIZE(axp20x_pek_resources),
-		.resources		= axp20x_pek_resources,
+		.name		= "axp20x-pek",
+		.num_resources	= ARRAY_SIZE(axp20x_pek_resources),
+		.resources	= axp20x_pek_resources,
 	}, {
-		.name			= "axp20x-regulator",
+		.name		= "axp20x-regulator",
+	}, {
+		.name		= "axp20x-usb-power-supply",
+		.of_compatible	= "x-powers,axp202-usb-power-supply",
+		.num_resources	= ARRAY_SIZE(axp20x_usb_power_supply_resources),
+		.resources	= axp20x_usb_power_supply_resources,
 	},
 };
 

Quoted 1 line

Add a cell for the usb power_supply part of the axp20x PMICs.

Why are you duplicating the subject line?

Quoted 10 lines

Note that this cell is only for the usb power_supply part and not the ac-power / battery-charger / rtc-backup-bat-charger bits.

Depending on the board each of those must be enabled / disabled separately in devicetree as most boards do not use all 4. So in dt each one needs its own child-node of the axp20x node. Another reason for using separate child nodes for each is so that other devicetree nodes can have a power-supply property with a phandle referencing a node representing a single power-supply.

Quoted 3 lines

The decision to use a separate devicetree node for each is reflected on the kernel side by each getting its own mfd-cell / platform_device and platform-driver.

You don't really need to say any of this, as this is the 'norm'.

What you didn't mention however, is that you're taking the opportunity to fix some formatting issues and that there are no functional changes in these lines.

Review

Quoted 10 lines

Cc Bruno Pr?mont <[email protected]>

Signed-off-by Hans de Goede <[email protected]>

---
Changes in v2:

(quoted diff) +0 -3

-Use DEFINE_RES_IRQ_NAMED
-Change indentation of axp20x_cells initializers to avoid line wrapping
---
  drivers/mfd/axp20x.c | 20 ++++++++++++++++----
  1 file changed, 16 insertions(+), 4 deletions(-)

Patch looks okay however:

Acked-by Lee Jones <[email protected]>

Quoted 40 lines

drivers/mfd/axp20x.c +16 -4

index f9a3c2d..ca4a604 100644
@@ -113,6 +113,13 @@ static struct resource axp20x_pek_resources[] = {
  	},
  };
 
+static struct resource axp20x_usb_power_supply_resources[] = {
+	DEFINE_RES_IRQ_NAMED(AXP20X_IRQ_VBUS_PLUGIN, "VBUS_PLUGIN"),
+	DEFINE_RES_IRQ_NAMED(AXP20X_IRQ_VBUS_REMOVAL, "VBUS_REMOVAL"),
+	DEFINE_RES_IRQ_NAMED(AXP20X_IRQ_VBUS_VALID, "VBUS_VALID"),
+	DEFINE_RES_IRQ_NAMED(AXP20X_IRQ_VBUS_NOT_VALID, "VBUS_NOT_VALID"),
+};
+
  static struct resource axp22x_pek_resources[] = {
  	{
  		.name   = "PEK_DBR",

@@ -363,11 +370,16 @@ static const struct regmap_irq_chip axp288_regmap_irq_chip = {
 
  static struct mfd_cell axp20x_cells[] = {
  	{
-		.name			= "axp20x-pek",
-		.num_resources		= ARRAY_SIZE(axp20x_pek_resources),
-		.resources		= axp20x_pek_resources,
+		.name		= "axp20x-pek",
+		.num_resources	= ARRAY_SIZE(axp20x_pek_resources),
+		.resources	= axp20x_pek_resources,
  	}, {
-		.name			= "axp20x-regulator",
+		.name		= "axp20x-regulator",
+	}, {
+		.name		= "axp20x-usb-power-supply",
+		.of_compatible	= "x-powers,axp202-usb-power-supply",
+		.num_resources	= ARRAY_SIZE(axp20x_usb_power_supply_resources),
+		.resources	= axp20x_usb_power_supply_resources,
  	},
  };
 

Quoted 3 lines · Lee Jones

Quoted 1 line

Add a cell for the usb power_supply part of the axp20x PMICs.

Why are you duplicating the subject line?

Heh, because some maintainers insist that the main-body part of the commit message must stand by itself, without needing the subject to be understandable...

Quoted 14 lines

Quoted 13 lines

Note that this cell is only for the usb power_supply part and not the ac-power / battery-charger / rtc-backup-bat-charger bits.

Depending on the board each of those must be enabled / disabled separately in devicetree as most boards do not use all 4. So in dt each one needs its own child-node of the axp20x node. Another reason for using separate child nodes for each is so that other devicetree nodes can have a power-supply property with a phandle referencing a node representing a single power-supply.

The decision to use a separate devicetree node for each is reflected on the kernel side by each getting its own mfd-cell / platform_device and platform-driver.

Quoted 1 line

You don't really need to say any of this, as this is the 'norm'.

I agree it should be the norm, but I'm not sure if it actually is, while working on this I've seen several drivers which instantiate multiple power-supply class devices from a single mfd-cell. And this is what Bruno's original patches did, so I would prefer to keep this

Quoted 3 lines

What you didn't mention however, is that you're taking the opportunity to fix some formatting issues and that there are no functional changes in these lines.

That is the end result of your request to change the indentation to avoid line-wrapping :)

Quoted 12 lines

Review

Quoted 9 lines

Cc Bruno Pr?mont <[email protected]>

Signed-off-by Hans de Goede <[email protected]>

---
Changes in v2:

(quoted diff) +0 -3

-Use DEFINE_RES_IRQ_NAMED
-Change indentation of axp20x_cells initializers to avoid line wrapping
---
 drivers/mfd/axp20x.c | 20 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

Patch looks okay however:

Quoted 1 line

Acked-by Lee Jones <[email protected]>

Thanks.

Regards,

Hans

Quoted 41 lines

Quoted 40 lines

drivers/mfd/axp20x.c +16 -4

index f9a3c2d..ca4a604 100644
@@ -113,6 +113,13 @@ static struct resource axp20x_pek_resources[] = {
 	},
 };
 
+static struct resource axp20x_usb_power_supply_resources[] = {
+	DEFINE_RES_IRQ_NAMED(AXP20X_IRQ_VBUS_PLUGIN, "VBUS_PLUGIN"),
+	DEFINE_RES_IRQ_NAMED(AXP20X_IRQ_VBUS_REMOVAL, "VBUS_REMOVAL"),
+	DEFINE_RES_IRQ_NAMED(AXP20X_IRQ_VBUS_VALID, "VBUS_VALID"),
+	DEFINE_RES_IRQ_NAMED(AXP20X_IRQ_VBUS_NOT_VALID, "VBUS_NOT_VALID"),
+};
+
 static struct resource axp22x_pek_resources[] = {
 	{
 		.name   = "PEK_DBR",

@@ -363,11 +370,16 @@ static const struct regmap_irq_chip axp288_regmap_irq_chip = {
 
 static struct mfd_cell axp20x_cells[] = {
 	{
-		.name			= "axp20x-pek",
-		.num_resources		= ARRAY_SIZE(axp20x_pek_resources),
-		.resources		= axp20x_pek_resources,
+		.name		= "axp20x-pek",
+		.num_resources	= ARRAY_SIZE(axp20x_pek_resources),
+		.resources	= axp20x_pek_resources,
 	}, {
-		.name			= "axp20x-regulator",
+		.name		= "axp20x-regulator",
+	}, {
+		.name		= "axp20x-usb-power-supply",
+		.of_compatible	= "x-powers,axp202-usb-power-supply",
+		.num_resources	= ARRAY_SIZE(axp20x_usb_power_supply_resources),
+		.resources	= axp20x_usb_power_supply_resources,
 	},
 };
 

This adds a driver for the usb power_supply bits of the axp20x PMICs.

I initially started writing my own driver, before coming aware of Bruno Pr?mont's excellent earlier RFC with a driver for this.

My driver was lacking CURRENT_MAX and VOLTAGE_MIN support Bruno's drvier has, so I've copied the code for those from his driver.

Note that the AC-power-supply and battery charger bits will need separate drivers. Each one needs its own devictree child-node so that other devicetree nodes can reference the right power-supply, and thus each one will get its own mfd-cell / platform_device and platform-driver.

Cc Bruno Pr?mont <[email protected]>

Signed-off-by Hans de Goede <[email protected]>

---
Changes in v2:

 4 files changed, 275 insertions(+)
 create mode 100644 drivers/power/axp20x_usb_power.c

drivers/power/Kconfig +7 -0

index 4091fb0..1fee60c 100644
@@ -439,6 +439,13 @@ config BATTERY_RT5033
 	  The fuelgauge calculates and determines the battery state of charge
 	  according to battery open circuit voltage.
 
+config AXP20X_POWER
+	tristate "AXP20x power supply driver"
+	depends on MFD_AXP20X
+	help
+	  This driver provides support for the power supply features of
+	  AXP20x PMIC.
+
 source "drivers/power/reset/Kconfig"
 
 endif # POWER_SUPPLY

drivers/power/Makefile +1 -0

index b7b0181..ae0f27d 100644
@@ -9,6 +9,7 @@ obj-$(CONFIG_GENERIC_ADC_BATTERY)	+= generic-adc-battery.o
 
 obj-$(CONFIG_PDA_POWER)		+= pda_power.o
 obj-$(CONFIG_APM_POWER)		+= apm_power.o
+obj-$(CONFIG_AXP20X_POWER)	+= axp20x_usb_power.o
 obj-$(CONFIG_MAX8925_POWER)	+= max8925_power.o
 obj-$(CONFIG_WM831X_BACKUP)	+= wm831x_backup.o
 obj-$(CONFIG_WM831X_POWER)	+= wm831x_power.o

drivers/power/axp20x_usb_power.c new file +243 -0

new file mode 100644
index 0000000..09f388e
@@ -0,0 +1,243 @@
+/*
+ * AXP20x PMIC USB power supply status driver
+ *
+ * Copyright (C) 2015 Hans de Goede <[email protected]>
+ * Copyright (C) 2014 Bruno Pr?mont <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under  the terms of the GNU General  Public License as published by the
+ * Free Software Foundation;  either version 2 of the License, or (at your
+ * option) any later version.
+ */
+
+#include <linux/device.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/mfd/axp20x.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/power_supply.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+
+#define DRVNAME "axp20x-usb-power-supply"
+
+#define AXP20X_PWR_STATUS_VBUS_PRESENT	BIT(5)
+#define AXP20X_PWR_STATUS_VBUS_USED	BIT(4)
+
+#define AXP20X_USB_STATUS_VBUS_VALID	BIT(2)
+
+#define AXP20X_VBUS_VHOLD_uV(b)		(4000000 + (((b) >> 3) & 7) * 100000)
+#define AXP20X_VBUS_CLIMIT_MASK		3
+#define AXP20X_VBUC_CLIMIT_900mA	0
+#define AXP20X_VBUC_CLIMIT_500mA	1
+#define AXP20X_VBUC_CLIMIT_100mA	2
+#define AXP20X_VBUC_CLIMIT_NONE		3
+
+#define AXP20X_ADC_EN1_VBUS_CURR	BIT(2)
+#define AXP20X_ADC_EN1_VBUS_VOLT	BIT(3)
+
+#define AXP20X_VBUS_MON_VBUS_VALID	BIT(3)
+
+struct axp20x_usb_power {
+	struct regmap *regmap;
+	struct power_supply *supply;
+};
+
+static irqreturn_t axp20x_usb_power_irq(int irq, void *devid)
+{
+	struct axp20x_usb_power *power = devid;
+
+	power_supply_changed(power->supply);
+
+	return IRQ_HANDLED;
+}
+
+static int axp20x_usb_power_get_property(struct power_supply *psy,
+	enum power_supply_property psp, union power_supply_propval *val)
+{
+	struct axp20x_usb_power *power = power_supply_get_drvdata(psy);
+	unsigned int input, v;
+	int r;
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_VOLTAGE_MIN:
+		r = regmap_read(power->regmap, AXP20X_VBUS_IPSOUT_MGMT, &v);
+		if (r)
+			return r;
+
+		val->intval = AXP20X_VBUS_VHOLD_uV(v);
+		return 0;
+	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
+		r = axp20x_read_variable_width(power->regmap,
+					       AXP20X_VBUS_V_ADC_H, 12);
+		if (r < 0)
+			return r;
+
+		val->intval = r * 1700; /* 1 step = 1.7 mV */
+		return 0;
+	case POWER_SUPPLY_PROP_CURRENT_MAX:
+		r = regmap_read(power->regmap, AXP20X_VBUS_IPSOUT_MGMT, &v);
+		if (r)
+			return r;
+
+		switch (v & AXP20X_VBUS_CLIMIT_MASK) {
+		case AXP20X_VBUC_CLIMIT_100mA:
+			val->intval = 100000;
+			break;
+		case AXP20X_VBUC_CLIMIT_500mA:
+			val->intval = 500000;
+			break;
+		case AXP20X_VBUC_CLIMIT_900mA:
+			val->intval = 900000;
+			break;
+		case AXP20X_VBUC_CLIMIT_NONE:
+			val->intval = -1;
+			break;
+		}
+		return 0;
+	case POWER_SUPPLY_PROP_CURRENT_NOW:
+		r = axp20x_read_variable_width(power->regmap,
+					       AXP20X_VBUS_I_ADC_H, 12);
+		if (r < 0)
+			return r;
+
+		val->intval = r * 375; /* 1 step = 0.375 mA */
+		return 0;
+	default:
+		break;
+	}
+
+	/* All the properties below need the input-status reg value */
+	r = regmap_read(power->regmap, AXP20X_PWR_INPUT_STATUS, &input);
+	if (r)
+		return r;
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_HEALTH:
+		if (!(input & AXP20X_PWR_STATUS_VBUS_PRESENT)) {
+			val->intval = POWER_SUPPLY_HEALTH_UNKNOWN;
+			break;
+		}
+
+		r = regmap_read(power->regmap, AXP20X_USB_OTG_STATUS, &v);
+		if (r)
+			return r;
+
+		if (!(v & AXP20X_USB_STATUS_VBUS_VALID)) {
+			val->intval = POWER_SUPPLY_HEALTH_UNSPEC_FAILURE;
+			break;
+		}
+
+		val->intval = POWER_SUPPLY_HEALTH_GOOD;
+		break;
+	case POWER_SUPPLY_PROP_PRESENT:
+		val->intval = !!(input & AXP20X_PWR_STATUS_VBUS_PRESENT);
+		break;
+	case POWER_SUPPLY_PROP_ONLINE:
+		val->intval = !!(input & AXP20X_PWR_STATUS_VBUS_USED);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static enum power_supply_property axp20x_usb_power_properties[] = {
+	POWER_SUPPLY_PROP_HEALTH,
+	POWER_SUPPLY_PROP_PRESENT,
+	POWER_SUPPLY_PROP_ONLINE,
+	POWER_SUPPLY_PROP_VOLTAGE_MIN,
+	POWER_SUPPLY_PROP_VOLTAGE_NOW,
+	POWER_SUPPLY_PROP_CURRENT_MAX,
+	POWER_SUPPLY_PROP_CURRENT_NOW,
+};
+
+static const struct power_supply_desc axp20x_usb_power_desc = {
+	.name = "axp20x-usb",
+	.type = POWER_SUPPLY_TYPE_USB,
+	.properties = axp20x_usb_power_properties,
+	.num_properties = ARRAY_SIZE(axp20x_usb_power_properties),
+	.get_property = axp20x_usb_power_get_property,
+};
+
+static int axp20x_usb_power_probe(struct platform_device *pdev)
+{
+	struct axp20x_dev *axp20x = dev_get_drvdata(pdev->dev.parent);
+	struct power_supply_config psy_cfg = {};
+	struct axp20x_usb_power *power;
+	static const char * const irq_names[] = { "VBUS_PLUGIN",
+		"VBUS_REMOVAL", "VBUS_VALID", "VBUS_NOT_VALID" };
+	int i, irq, r;
+
+	if (!of_device_is_available(pdev->dev.of_node))
+		return -ENODEV;
+
+	power = devm_kzalloc(&pdev->dev, sizeof(*power), GFP_KERNEL);
+	if (!power)
+		return -ENOMEM;
+
+	power->regmap = axp20x->regmap;
+
+	/* Enable vbus valid checking */
+	r = regmap_update_bits(power->regmap, AXP20X_VBUS_MON,
+		    AXP20X_VBUS_MON_VBUS_VALID, AXP20X_VBUS_MON_VBUS_VALID);
+	if (r)
+		return r;
+
+	/* Enable vbus voltage and current measurement */
+	r = regmap_update_bits(power->regmap, AXP20X_ADC_EN1,
+			AXP20X_ADC_EN1_VBUS_CURR | AXP20X_ADC_EN1_VBUS_VOLT,
+			AXP20X_ADC_EN1_VBUS_CURR | AXP20X_ADC_EN1_VBUS_VOLT);
+	if (r)
+		return r;
+
+	psy_cfg.of_node = pdev->dev.of_node;
+	psy_cfg.drv_data = power;
+
+	power->supply = devm_power_supply_register(&pdev->dev,
+					&axp20x_usb_power_desc, &psy_cfg);
+	if (IS_ERR(power->supply))
+		return PTR_ERR(power->supply);
+
+	/* Request irqs after registering, as irqs may trigger immediately */
+	for (i = 0; i < ARRAY_SIZE(irq_names); i++) {
+		irq = platform_get_irq_byname(pdev, irq_names[i]);
+		if (irq < 0) {
+			dev_warn(&pdev->dev, "No IRQ for %s: %d\n",
+				 irq_names[i], irq);
+			continue;
+		}
+		irq = regmap_irq_get_virq(axp20x->regmap_irqc, irq);
+		r = devm_request_any_context_irq(&pdev->dev, irq,
+				axp20x_usb_power_irq, 0, DRVNAME, power);
+		if (r < 0)
+			dev_warn(&pdev->dev, "Error requesting %s IRQ: %d\n",
+				 irq_names[i], r);
+	}
+
+	return 0;
+}
+
+static const struct of_device_id axp20x_usb_power_match[] = {
+	{ .compatible = "x-powers,axp202-usb-power-supply" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, axp20x_usb_power_match);
+
+static struct platform_driver axp20x_usb_power_driver = {
+	.probe = axp20x_usb_power_probe,
+	.driver = {
+		.name = DRVNAME,
+		.of_match_table = axp20x_usb_power_match,
+	},
+};
+
+module_platform_driver(axp20x_usb_power_driver);
+
+MODULE_AUTHOR("Hans de Goede <[email protected]>");
+MODULE_DESCRIPTION("AXP20x PMIC USB power supply status driver");
+MODULE_LICENSE("GPL");

include/linux/mfd/axp20x.h +24 -0

index 6d8b39a..8ec996e 100644
@@ -11,6 +11,8 @@
 #ifndef __LINUX_MFD_AXP20X_H
 #define __LINUX_MFD_AXP20X_H
 
+#include <linux/regmap.h>
+
 enum {
 	AXP202_ID = 0,
 	AXP209_ID,

@@ -372,4 +374,26 @@ struct axp288_extcon_pdata {
 	struct gpio_desc *gpio_mux_cntl;
 };
 
+/* generic helper function for reading 9-16 bit wide regs */
+static inline int axp20x_read_variable_width(struct regmap *regmap,
+	unsigned int reg, unsigned int width)
+{
+	unsigned int reg_val, result;
+	int err;
+
+	err = regmap_read(regmap, reg, &reg_val);
+	if (err)
+		return err;
+
+	result = reg_val << (width - 8);
+
+	err = regmap_read(regmap, reg + 1, &reg_val);
+	if (err)
+		return err;
+
+	result |= reg_val;
+
+	return result;
+}
+
 #endif /* __LINUX_MFD_AXP20X_H */