drivers/iio/adc/axp288_adc.c - third_party/linux - Git at Google

 /*
  * axp288_adc.c - X-Powers AXP288 PMIC ADC Driver
  *
  * Copyright (C) 2014 Intel Corporation
  *
  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  *
  * 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; version 2 of the License.
  *
  * This program is distributed in the hope that it will be useful, but
  * WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	See the GNU
  * General Public License for more details.
  *
  */

 #include <linux/dmi.h>
 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/device.h>
 #include <linux/regmap.h>
 #include <linux/mfd/axp20x.h>
 #include <linux/platform_device.h>

 #include <linux/iio/iio.h>
 #include <linux/iio/machine.h>
 #include <linux/iio/driver.h>

 /*
  * This mask enables all ADCs except for the battery temp-sensor (TS), that is
  * left as-is to avoid breaking charging on devices without a temp-sensor.
  */
 #define AXP288_ADC_EN_MASK				0xF0
 #define AXP288_ADC_TS_ENABLE				0x01

 #define AXP288_ADC_TS_BIAS_MASK				GENMASK(5, 4)
 #define AXP288_ADC_TS_BIAS_20UA				(0 << 4)
 #define AXP288_ADC_TS_BIAS_40UA				(1 << 4)
 #define AXP288_ADC_TS_BIAS_60UA				(2 << 4)
 #define AXP288_ADC_TS_BIAS_80UA				(3 << 4)
 #define AXP288_ADC_TS_CURRENT_ON_OFF_MASK		GENMASK(1, 0)
 #define AXP288_ADC_TS_CURRENT_OFF			(0 << 0)
 #define AXP288_ADC_TS_CURRENT_ON_WHEN_CHARGING		(1 << 0)
 #define AXP288_ADC_TS_CURRENT_ON_ONDEMAND		(2 << 0)
 #define AXP288_ADC_TS_CURRENT_ON			(3 << 0)

 enum axp288_adc_id {
 	AXP288_ADC_TS,
 	AXP288_ADC_PMIC,
 	AXP288_ADC_GP,
 	AXP288_ADC_BATT_CHRG_I,
 	AXP288_ADC_BATT_DISCHRG_I,
 	AXP288_ADC_BATT_V,
 	AXP288_ADC_NR_CHAN,
 };

 struct axp288_adc_info {
 	int irq;
 	struct regmap *regmap;
 	bool ts_enabled;
 };

 static const struct iio_chan_spec axp288_adc_channels[] = {
 	{
 		.indexed = 1,
 		.type = IIO_TEMP,
 		.channel = 0,
 		.address = AXP288_TS_ADC_H,
 		.datasheet_name = "TS_PIN",
 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 	}, {
 		.indexed = 1,
 		.type = IIO_TEMP,
 		.channel = 1,
 		.address = AXP288_PMIC_ADC_H,
 		.datasheet_name = "PMIC_TEMP",
 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 	}, {
 		.indexed = 1,
 		.type = IIO_TEMP,
 		.channel = 2,
 		.address = AXP288_GP_ADC_H,
 		.datasheet_name = "GPADC",
 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 	}, {
 		.indexed = 1,
 		.type = IIO_CURRENT,
 		.channel = 3,
 		.address = AXP20X_BATT_CHRG_I_H,
 		.datasheet_name = "BATT_CHG_I",
 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 	}, {
 		.indexed = 1,
 		.type = IIO_CURRENT,
 		.channel = 4,
 		.address = AXP20X_BATT_DISCHRG_I_H,
 		.datasheet_name = "BATT_DISCHRG_I",
 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 	}, {
 		.indexed = 1,
 		.type = IIO_VOLTAGE,
 		.channel = 5,
 		.address = AXP20X_BATT_V_H,
 		.datasheet_name = "BATT_V",
 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 	},
 };

 /* for consumer drivers */
 static struct iio_map axp288_adc_default_maps[] = {
 	IIO_MAP("TS_PIN", "axp288-batt", "axp288-batt-temp"),
 	IIO_MAP("PMIC_TEMP", "axp288-pmic", "axp288-pmic-temp"),
 	IIO_MAP("GPADC", "axp288-gpadc", "axp288-system-temp"),
 	IIO_MAP("BATT_CHG_I", "axp288-chrg", "axp288-chrg-curr"),
 	IIO_MAP("BATT_DISCHRG_I", "axp288-chrg", "axp288-chrg-d-curr"),
 	IIO_MAP("BATT_V", "axp288-batt", "axp288-batt-volt"),
 	{},
 };

 static int axp288_adc_read_channel(int *val, unsigned long address,
 				struct regmap *regmap)
 {
 	u8 buf[2];

 	if (regmap_bulk_read(regmap, address, buf, 2))
 		return -EIO;
 	*val = (buf[0] << 4) + ((buf[1] >> 4) & 0x0F);

 	return IIO_VAL_INT;
 }

 /*
  * The current-source used for the battery temp-sensor (TS) is shared
  * with the GPADC. For proper fuel-gauge and charger operation the TS
  * current-source needs to be permanently on. But to read the GPADC we
  * need to temporary switch the TS current-source to ondemand, so that
  * the GPADC can use it, otherwise we will always read an all 0 value.
  */
 static int axp288_adc_set_ts(struct axp288_adc_info *info,
 			     unsigned int mode, unsigned long address)
 {
 	int ret;

 	/* No need to switch the current-source if the TS pin is disabled */
 	if (!info->ts_enabled)
 		return 0;

 	/* Channels other than GPADC do not need the current source */
 	if (address != AXP288_GP_ADC_H)
 		return 0;

 	ret = regmap_update_bits(info->regmap, AXP288_ADC_TS_PIN_CTRL,
 				 AXP288_ADC_TS_CURRENT_ON_OFF_MASK, mode);
 	if (ret)
 		return ret;

 	/* When switching to the GPADC pin give things some time to settle */
 	if (mode == AXP288_ADC_TS_CURRENT_ON_ONDEMAND)
 		usleep_range(6000, 10000);

 	return 0;
 }

 static int axp288_adc_read_raw(struct iio_dev *indio_dev,
 			struct iio_chan_spec const *chan,
 			int *val, int *val2, long mask)
 {
 	int ret;
 	struct axp288_adc_info *info = iio_priv(indio_dev);

 	mutex_lock(&indio_dev->mlock);
 	switch (mask) {
 	case IIO_CHAN_INFO_RAW:
 		if (axp288_adc_set_ts(info, AXP288_ADC_TS_CURRENT_ON_ONDEMAND,
 					chan->address)) {
 			dev_err(&indio_dev->dev, "GPADC mode\n");
 			ret = -EINVAL;
 			break;
 		}
 		ret = axp288_adc_read_channel(val, chan->address, info->regmap);
 		if (axp288_adc_set_ts(info, AXP288_ADC_TS_CURRENT_ON,
 						chan->address))
 			dev_err(&indio_dev->dev, "TS pin restore\n");
 		break;
 	default:
 		ret = -EINVAL;
 	}
 	mutex_unlock(&indio_dev->mlock);

 	return ret;
 }

 /*
  * We rely on the machine's firmware to correctly setup the TS pin bias current
  * at boot. This lists systems with broken fw where we need to set it ourselves.
  */
 static const struct dmi_system_id axp288_adc_ts_bias_override[] = {
 	{
 		/* Lenovo Ideapad 100S (11 inch) */
 		.matches = {
 		  DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
 		  DMI_MATCH(DMI_PRODUCT_VERSION, "Lenovo ideapad 100S-11IBY"),
 		},
 		.driver_data = (void *)(uintptr_t)AXP288_ADC_TS_BIAS_80UA,
 	},
 	{
 		/* Nuvision Solo 10 Draw */
 		.matches = {
 		  DMI_MATCH(DMI_SYS_VENDOR, "TMAX"),
 		  DMI_MATCH(DMI_PRODUCT_NAME, "TM101W610L"),
 		},
 		.driver_data = (void *)(uintptr_t)AXP288_ADC_TS_BIAS_80UA,
 	},
 	{}
 };

 static int axp288_adc_initialize(struct axp288_adc_info *info)
 {
 	const struct dmi_system_id *bias_override;
 	int ret, adc_enable_val;

 	bias_override = dmi_first_match(axp288_adc_ts_bias_override);
 	if (bias_override) {
 		ret = regmap_update_bits(info->regmap, AXP288_ADC_TS_PIN_CTRL,
 					 AXP288_ADC_TS_BIAS_MASK,
 					 (uintptr_t)bias_override->driver_data);
 		if (ret)
 			return ret;
 	}

 	/*
 	 * Determine if the TS pin is enabled and set the TS current-source
 	 * accordingly.
 	 */
 	ret = regmap_read(info->regmap, AXP20X_ADC_EN1, &adc_enable_val);
 	if (ret)
 		return ret;

 	if (adc_enable_val & AXP288_ADC_TS_ENABLE) {
 		info->ts_enabled = true;
 		ret = regmap_update_bits(info->regmap, AXP288_ADC_TS_PIN_CTRL,
 					 AXP288_ADC_TS_CURRENT_ON_OFF_MASK,
 					 AXP288_ADC_TS_CURRENT_ON);
 	} else {
 		info->ts_enabled = false;
 		ret = regmap_update_bits(info->regmap, AXP288_ADC_TS_PIN_CTRL,
 					 AXP288_ADC_TS_CURRENT_ON_OFF_MASK,
 					 AXP288_ADC_TS_CURRENT_OFF);
 	}
 	if (ret)
 		return ret;

 	/* Turn on the ADC for all channels except TS, leave TS as is */
 	return regmap_update_bits(info->regmap, AXP20X_ADC_EN1,
 				  AXP288_ADC_EN_MASK, AXP288_ADC_EN_MASK);
 }

 static const struct iio_info axp288_adc_iio_info = {
 	.read_raw = &axp288_adc_read_raw,
 };

 static int axp288_adc_probe(struct platform_device *pdev)
 {
 	int ret;
 	struct axp288_adc_info *info;
 	struct iio_dev *indio_dev;
 	struct axp20x_dev *axp20x = dev_get_drvdata(pdev->dev.parent);

 	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*info));
 	if (!indio_dev)
 		return -ENOMEM;

 	info = iio_priv(indio_dev);
 	info->irq = platform_get_irq(pdev, 0);
 	if (info->irq < 0) {
 		dev_err(&pdev->dev, "no irq resource?\n");
 		return info->irq;
 	}
 	platform_set_drvdata(pdev, indio_dev);
 	info->regmap = axp20x->regmap;
 	/*
 	 * Set ADC to enabled state at all time, including system suspend.
 	 * otherwise internal fuel gauge functionality may be affected.
 	 */
 	ret = axp288_adc_initialize(info);
 	if (ret) {
 		dev_err(&pdev->dev, "unable to enable ADC device\n");
 		return ret;
 	}

 	indio_dev->dev.parent = &pdev->dev;
 	indio_dev->name = pdev->name;
 	indio_dev->channels = axp288_adc_channels;
 	indio_dev->num_channels = ARRAY_SIZE(axp288_adc_channels);
 	indio_dev->info = &axp288_adc_iio_info;
 	indio_dev->modes = INDIO_DIRECT_MODE;
 	ret = iio_map_array_register(indio_dev, axp288_adc_default_maps);
 	if (ret < 0)
 		return ret;

 	ret = iio_device_register(indio_dev);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "unable to register iio device\n");
 		goto err_array_unregister;
 	}
 	return 0;

 err_array_unregister:
 	iio_map_array_unregister(indio_dev);

 	return ret;
 }

 static int axp288_adc_remove(struct platform_device *pdev)
 {
 	struct iio_dev *indio_dev = platform_get_drvdata(pdev);

 	iio_device_unregister(indio_dev);
 	iio_map_array_unregister(indio_dev);

 	return 0;
 }

 static const struct platform_device_id axp288_adc_id_table[] = {
 	{ .name = "axp288_adc" },
 	{},
 };

 static struct platform_driver axp288_adc_driver = {
 	.probe = axp288_adc_probe,
 	.remove = axp288_adc_remove,
 	.id_table = axp288_adc_id_table,
 	.driver = {
 		.name = "axp288_adc",
 	},
 };

 MODULE_DEVICE_TABLE(platform, axp288_adc_id_table);

 module_platform_driver(axp288_adc_driver);

 MODULE_AUTHOR("Jacob Pan <jacob.jun.pan@linux.intel.com>");
 MODULE_DESCRIPTION("X-Powers AXP288 ADC Driver");
 MODULE_LICENSE("GPL");
	/*
	* axp288_adc.c - X-Powers AXP288 PMIC ADC Driver
	*
	* Copyright (C) 2014 Intel Corporation
	*
	* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
	*
	* 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; version 2 of the License.
	*
	* This program is distributed in the hope that it will be useful, but
	* WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	* General Public License for more details.
	*
	*/

	#include <linux/dmi.h>
	#include <linux/module.h>
	#include <linux/kernel.h>
	#include <linux/device.h>
	#include <linux/regmap.h>
	#include <linux/mfd/axp20x.h>
	#include <linux/platform_device.h>

	#include <linux/iio/iio.h>
	#include <linux/iio/machine.h>
	#include <linux/iio/driver.h>

	/*
	* This mask enables all ADCs except for the battery temp-sensor (TS), that is
	* left as-is to avoid breaking charging on devices without a temp-sensor.
	*/
	#define AXP288_ADC_EN_MASK 0xF0
	#define AXP288_ADC_TS_ENABLE 0x01

	#define AXP288_ADC_TS_BIAS_MASK GENMASK(5, 4)
	#define AXP288_ADC_TS_BIAS_20UA (0 << 4)
	#define AXP288_ADC_TS_BIAS_40UA (1 << 4)
	#define AXP288_ADC_TS_BIAS_60UA (2 << 4)
	#define AXP288_ADC_TS_BIAS_80UA (3 << 4)
	#define AXP288_ADC_TS_CURRENT_ON_OFF_MASK GENMASK(1, 0)
	#define AXP288_ADC_TS_CURRENT_OFF (0 << 0)
	#define AXP288_ADC_TS_CURRENT_ON_WHEN_CHARGING (1 << 0)
	#define AXP288_ADC_TS_CURRENT_ON_ONDEMAND (2 << 0)
	#define AXP288_ADC_TS_CURRENT_ON (3 << 0)

	enum axp288_adc_id {
	AXP288_ADC_TS,
	AXP288_ADC_PMIC,
	AXP288_ADC_GP,
	AXP288_ADC_BATT_CHRG_I,
	AXP288_ADC_BATT_DISCHRG_I,
	AXP288_ADC_BATT_V,
	AXP288_ADC_NR_CHAN,
	};

	struct axp288_adc_info {
	int irq;
	struct regmap *regmap;
	bool ts_enabled;
	};

	static const struct iio_chan_spec axp288_adc_channels[] = {
	{
	.indexed = 1,
	.type = IIO_TEMP,
	.channel = 0,
	.address = AXP288_TS_ADC_H,
	.datasheet_name = "TS_PIN",
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
	}, {
	.indexed = 1,
	.type = IIO_TEMP,
	.channel = 1,
	.address = AXP288_PMIC_ADC_H,
	.datasheet_name = "PMIC_TEMP",
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
	}, {
	.indexed = 1,
	.type = IIO_TEMP,
	.channel = 2,
	.address = AXP288_GP_ADC_H,
	.datasheet_name = "GPADC",
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
	}, {
	.indexed = 1,
	.type = IIO_CURRENT,
	.channel = 3,
	.address = AXP20X_BATT_CHRG_I_H,
	.datasheet_name = "BATT_CHG_I",
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
	}, {
	.indexed = 1,
	.type = IIO_CURRENT,
	.channel = 4,
	.address = AXP20X_BATT_DISCHRG_I_H,
	.datasheet_name = "BATT_DISCHRG_I",
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
	}, {
	.indexed = 1,
	.type = IIO_VOLTAGE,
	.channel = 5,
	.address = AXP20X_BATT_V_H,
	.datasheet_name = "BATT_V",
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
	},
	};

	/* for consumer drivers */
	static struct iio_map axp288_adc_default_maps[] = {
	IIO_MAP("TS_PIN", "axp288-batt", "axp288-batt-temp"),
	IIO_MAP("PMIC_TEMP", "axp288-pmic", "axp288-pmic-temp"),
	IIO_MAP("GPADC", "axp288-gpadc", "axp288-system-temp"),
	IIO_MAP("BATT_CHG_I", "axp288-chrg", "axp288-chrg-curr"),
	IIO_MAP("BATT_DISCHRG_I", "axp288-chrg", "axp288-chrg-d-curr"),
	IIO_MAP("BATT_V", "axp288-batt", "axp288-batt-volt"),
	{},
	};

	static int axp288_adc_read_channel(int *val, unsigned long address,
	struct regmap *regmap)
	{
	u8 buf[2];

	if (regmap_bulk_read(regmap, address, buf, 2))
	return -EIO;
	*val = (buf[0] << 4) + ((buf[1] >> 4) & 0x0F);

	return IIO_VAL_INT;
	}

	/*
	* The current-source used for the battery temp-sensor (TS) is shared
	* with the GPADC. For proper fuel-gauge and charger operation the TS
	* current-source needs to be permanently on. But to read the GPADC we
	* need to temporary switch the TS current-source to ondemand, so that
	* the GPADC can use it, otherwise we will always read an all 0 value.
	*/
	static int axp288_adc_set_ts(struct axp288_adc_info *info,
	unsigned int mode, unsigned long address)
	{
	int ret;

	/* No need to switch the current-source if the TS pin is disabled */
	if (!info->ts_enabled)
	return 0;

	/* Channels other than GPADC do not need the current source */
	if (address != AXP288_GP_ADC_H)
	return 0;

	ret = regmap_update_bits(info->regmap, AXP288_ADC_TS_PIN_CTRL,
	AXP288_ADC_TS_CURRENT_ON_OFF_MASK, mode);
	if (ret)
	return ret;

	/* When switching to the GPADC pin give things some time to settle */
	if (mode == AXP288_ADC_TS_CURRENT_ON_ONDEMAND)
	usleep_range(6000, 10000);

	return 0;
	}

	static int axp288_adc_read_raw(struct iio_dev *indio_dev,
	struct iio_chan_spec const *chan,
	int val, int val2, long mask)
	{
	int ret;
	struct axp288_adc_info *info = iio_priv(indio_dev);

	mutex_lock(&indio_dev->mlock);
	switch (mask) {
	case IIO_CHAN_INFO_RAW:
	if (axp288_adc_set_ts(info, AXP288_ADC_TS_CURRENT_ON_ONDEMAND,
	chan->address)) {
	dev_err(&indio_dev->dev, "GPADC mode\n");
	ret = -EINVAL;
	break;
	}
	ret = axp288_adc_read_channel(val, chan->address, info->regmap);
	if (axp288_adc_set_ts(info, AXP288_ADC_TS_CURRENT_ON,
	chan->address))
	dev_err(&indio_dev->dev, "TS pin restore\n");
	break;
	default:
	ret = -EINVAL;
	}
	mutex_unlock(&indio_dev->mlock);

	return ret;
	}

	/*
	* We rely on the machine's firmware to correctly setup the TS pin bias current
	* at boot. This lists systems with broken fw where we need to set it ourselves.
	*/
	static const struct dmi_system_id axp288_adc_ts_bias_override[] = {
	{
	/* Lenovo Ideapad 100S (11 inch) */
	.matches = {
	DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
	DMI_MATCH(DMI_PRODUCT_VERSION, "Lenovo ideapad 100S-11IBY"),
	},
	.driver_data = (void *)(uintptr_t)AXP288_ADC_TS_BIAS_80UA,
	},
	{
	/* Nuvision Solo 10 Draw */
	.matches = {
	DMI_MATCH(DMI_SYS_VENDOR, "TMAX"),
	DMI_MATCH(DMI_PRODUCT_NAME, "TM101W610L"),
	},
	.driver_data = (void *)(uintptr_t)AXP288_ADC_TS_BIAS_80UA,
	},
	{}
	};

	static int axp288_adc_initialize(struct axp288_adc_info *info)
	{
	const struct dmi_system_id *bias_override;
	int ret, adc_enable_val;

	bias_override = dmi_first_match(axp288_adc_ts_bias_override);
	if (bias_override) {
	ret = regmap_update_bits(info->regmap, AXP288_ADC_TS_PIN_CTRL,
	AXP288_ADC_TS_BIAS_MASK,
	(uintptr_t)bias_override->driver_data);
	if (ret)
	return ret;
	}

	/*
	* Determine if the TS pin is enabled and set the TS current-source
	* accordingly.
	*/
	ret = regmap_read(info->regmap, AXP20X_ADC_EN1, &adc_enable_val);
	if (ret)
	return ret;

	if (adc_enable_val & AXP288_ADC_TS_ENABLE) {
	info->ts_enabled = true;
	ret = regmap_update_bits(info->regmap, AXP288_ADC_TS_PIN_CTRL,
	AXP288_ADC_TS_CURRENT_ON_OFF_MASK,
	AXP288_ADC_TS_CURRENT_ON);
	} else {
	info->ts_enabled = false;
	ret = regmap_update_bits(info->regmap, AXP288_ADC_TS_PIN_CTRL,
	AXP288_ADC_TS_CURRENT_ON_OFF_MASK,
	AXP288_ADC_TS_CURRENT_OFF);
	}
	if (ret)
	return ret;

	/* Turn on the ADC for all channels except TS, leave TS as is */
	return regmap_update_bits(info->regmap, AXP20X_ADC_EN1,
	AXP288_ADC_EN_MASK, AXP288_ADC_EN_MASK);
	}

	static const struct iio_info axp288_adc_iio_info = {
	.read_raw = &axp288_adc_read_raw,
	};

	static int axp288_adc_probe(struct platform_device *pdev)
	{
	int ret;
	struct axp288_adc_info *info;
	struct iio_dev *indio_dev;
	struct axp20x_dev *axp20x = dev_get_drvdata(pdev->dev.parent);

	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*info));
	if (!indio_dev)
	return -ENOMEM;

	info = iio_priv(indio_dev);
	info->irq = platform_get_irq(pdev, 0);
	if (info->irq < 0) {
	dev_err(&pdev->dev, "no irq resource?\n");
	return info->irq;
	}
	platform_set_drvdata(pdev, indio_dev);
	info->regmap = axp20x->regmap;
	/*
	* Set ADC to enabled state at all time, including system suspend.
	* otherwise internal fuel gauge functionality may be affected.
	*/
	ret = axp288_adc_initialize(info);
	if (ret) {
	dev_err(&pdev->dev, "unable to enable ADC device\n");
	return ret;
	}

	indio_dev->dev.parent = &pdev->dev;
	indio_dev->name = pdev->name;
	indio_dev->channels = axp288_adc_channels;
	indio_dev->num_channels = ARRAY_SIZE(axp288_adc_channels);
	indio_dev->info = &axp288_adc_iio_info;
	indio_dev->modes = INDIO_DIRECT_MODE;
	ret = iio_map_array_register(indio_dev, axp288_adc_default_maps);
	if (ret < 0)
	return ret;

	ret = iio_device_register(indio_dev);
	if (ret < 0) {
	dev_err(&pdev->dev, "unable to register iio device\n");
	goto err_array_unregister;
	}
	return 0;

	err_array_unregister:
	iio_map_array_unregister(indio_dev);

	return ret;
	}

	static int axp288_adc_remove(struct platform_device *pdev)
	{
	struct iio_dev *indio_dev = platform_get_drvdata(pdev);

	iio_device_unregister(indio_dev);
	iio_map_array_unregister(indio_dev);

	return 0;
	}

	static const struct platform_device_id axp288_adc_id_table[] = {
	{ .name = "axp288_adc" },
	{},
	};

	static struct platform_driver axp288_adc_driver = {
	.probe = axp288_adc_probe,
	.remove = axp288_adc_remove,
	.id_table = axp288_adc_id_table,
	.driver = {
	.name = "axp288_adc",
	},
	};

	MODULE_DEVICE_TABLE(platform, axp288_adc_id_table);

	module_platform_driver(axp288_adc_driver);

	MODULE_AUTHOR("Jacob Pan <jacob.jun.pan@linux.intel.com>");
	MODULE_DESCRIPTION("X-Powers AXP288 ADC Driver");
	MODULE_LICENSE("GPL");