mfd: Add AAT2870 mfd driver

Add mfd core driver for AnalogicTech AAT2870.
The AAT2870 is communication through I2C and contains backlight and
regulator components.
Signed-off-by: NJin Park <jinyoungp@nvidia.com>
Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>

drivers/mfd/Kconfig

@@ -760,6 +760,16 @@ config MFD_PM8XXX_IRQ
 config TPS65911_COMPARATOR
 	tristate
 
+config MFD_AAT2870_CORE
+	bool "Support for the AnalogicTech AAT2870"
+	select MFD_CORE
+	depends on I2C=y && GPIOLIB
+	help
+	  If you say yes here you get support for the AAT2870.
+	  This driver provides common support for accessing the device,
+	  additional drivers must be enabled in order to use the
+	  functionality of the device.
+
 endif # MFD_SUPPORT
 
 menu "Multimedia Capabilities Port drivers"

drivers/mfd/Makefile

@@ -101,3 +101,4 @@ obj-$(CONFIG_MFD_OMAP_USB_HOST)	+= omap-usb-host.o
 obj-$(CONFIG_MFD_PM8921_CORE) 	+= pm8921-core.o
 obj-$(CONFIG_MFD_PM8XXX_IRQ) 	+= pm8xxx-irq.o
 obj-$(CONFIG_TPS65911_COMPARATOR)	+= tps65911-comparator.o
+obj-$(CONFIG_MFD_AAT2870_CORE)	+= aat2870-core.o

drivers/mfd/aat2870-core.c

+/*
+ * linux/drivers/mfd/aat2870-core.c
+ *
+ * Copyright (c) 2011, NVIDIA Corporation.
+ * Author: Jin Park <jinyoungp@nvidia.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/debugfs.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <linux/i2c.h>
+#include <linux/delay.h>
+#include <linux/gpio.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/aat2870.h>
+#include <linux/regulator/machine.h>
+
+static struct aat2870_register aat2870_regs[AAT2870_REG_NUM] = {
+	/* readable, writeable, value */
+	{ 0, 1, 0x00 },	/* 0x00 AAT2870_BL_CH_EN */
+	{ 0, 1, 0x16 },	/* 0x01 AAT2870_BLM */
+	{ 0, 1, 0x16 },	/* 0x02 AAT2870_BLS */
+	{ 0, 1, 0x56 },	/* 0x03 AAT2870_BL1 */
+	{ 0, 1, 0x56 },	/* 0x04 AAT2870_BL2 */
+	{ 0, 1, 0x56 },	/* 0x05 AAT2870_BL3 */
+	{ 0, 1, 0x56 },	/* 0x06 AAT2870_BL4 */
+	{ 0, 1, 0x56 },	/* 0x07 AAT2870_BL5 */
+	{ 0, 1, 0x56 },	/* 0x08 AAT2870_BL6 */
+	{ 0, 1, 0x56 },	/* 0x09 AAT2870_BL7 */
+	{ 0, 1, 0x56 },	/* 0x0A AAT2870_BL8 */
+	{ 0, 1, 0x00 },	/* 0x0B AAT2870_FLR */
+	{ 0, 1, 0x03 },	/* 0x0C AAT2870_FM */
+	{ 0, 1, 0x03 },	/* 0x0D AAT2870_FS */
+	{ 0, 1, 0x10 },	/* 0x0E AAT2870_ALS_CFG0 */
+	{ 0, 1, 0x06 },	/* 0x0F AAT2870_ALS_CFG1 */
+	{ 0, 1, 0x00 },	/* 0x10 AAT2870_ALS_CFG2 */
+	{ 1, 0, 0x00 },	/* 0x11 AAT2870_AMB */
+	{ 0, 1, 0x00 },	/* 0x12 AAT2870_ALS0 */
+	{ 0, 1, 0x00 },	/* 0x13 AAT2870_ALS1 */
+	{ 0, 1, 0x00 },	/* 0x14 AAT2870_ALS2 */
+	{ 0, 1, 0x00 },	/* 0x15 AAT2870_ALS3 */
+	{ 0, 1, 0x00 },	/* 0x16 AAT2870_ALS4 */
+	{ 0, 1, 0x00 },	/* 0x17 AAT2870_ALS5 */
+	{ 0, 1, 0x00 },	/* 0x18 AAT2870_ALS6 */
+	{ 0, 1, 0x00 },	/* 0x19 AAT2870_ALS7 */
+	{ 0, 1, 0x00 },	/* 0x1A AAT2870_ALS8 */
+	{ 0, 1, 0x00 },	/* 0x1B AAT2870_ALS9 */
+	{ 0, 1, 0x00 },	/* 0x1C AAT2870_ALSA */
+	{ 0, 1, 0x00 },	/* 0x1D AAT2870_ALSB */
+	{ 0, 1, 0x00 },	/* 0x1E AAT2870_ALSC */
+	{ 0, 1, 0x00 },	/* 0x1F AAT2870_ALSD */
+	{ 0, 1, 0x00 },	/* 0x20 AAT2870_ALSE */
+	{ 0, 1, 0x00 },	/* 0x21 AAT2870_ALSF */
+	{ 0, 1, 0x00 },	/* 0x22 AAT2870_SUB_SET */
+	{ 0, 1, 0x00 },	/* 0x23 AAT2870_SUB_CTRL */
+	{ 0, 1, 0x00 },	/* 0x24 AAT2870_LDO_AB */
+	{ 0, 1, 0x00 },	/* 0x25 AAT2870_LDO_CD */
+	{ 0, 1, 0x00 },	/* 0x26 AAT2870_LDO_EN */
+};
+
+static struct mfd_cell aat2870_devs[] = {
+	{
+		.name = "aat2870-backlight",
+		.id = AAT2870_ID_BL,
+		.pdata_size = sizeof(struct aat2870_bl_platform_data),
+	},
+	{
+		.name = "aat2870-regulator",
+		.id = AAT2870_ID_LDOA,
+		.pdata_size = sizeof(struct regulator_init_data),
+	},
+	{
+		.name = "aat2870-regulator",
+		.id = AAT2870_ID_LDOB,
+		.pdata_size = sizeof(struct regulator_init_data),
+	},
+	{
+		.name = "aat2870-regulator",
+		.id = AAT2870_ID_LDOC,
+		.pdata_size = sizeof(struct regulator_init_data),
+	},
+	{
+		.name = "aat2870-regulator",
+		.id = AAT2870_ID_LDOD,
+		.pdata_size = sizeof(struct regulator_init_data),
+	},
+};
+
+static int __aat2870_read(struct aat2870_data *aat2870, u8 addr, u8 *val)
+{
+	int ret;
+
+	if (addr >= AAT2870_REG_NUM) {
+		dev_err(aat2870->dev, "Invalid address, 0x%02x\n", addr);
+		return -EINVAL;
+	}
+
+	if (!aat2870->reg_cache[addr].readable) {
+		*val = aat2870->reg_cache[addr].value;
+		goto out;
+	}
+
+	ret = i2c_master_send(aat2870->client, &addr, 1);
+	if (ret < 0)
+		return ret;
+	if (ret != 1)
+		return -EIO;
+
+	ret = i2c_master_recv(aat2870->client, val, 1);
+	if (ret < 0)
+		return ret;
+	if (ret != 1)
+		return -EIO;
+
+out:
+	dev_dbg(aat2870->dev, "read: addr=0x%02x, val=0x%02x\n", addr, *val);
+	return 0;
+}
+
+static int __aat2870_write(struct aat2870_data *aat2870, u8 addr, u8 val)
+{
+	u8 msg[2];
+	int ret;
+
+	if (addr >= AAT2870_REG_NUM) {
+		dev_err(aat2870->dev, "Invalid address, 0x%02x\n", addr);
+		return -EINVAL;
+	}
+
+	if (!aat2870->reg_cache[addr].writeable) {
+		dev_err(aat2870->dev, "Address 0x%02x is not writeable\n",
+			addr);
+		return -EINVAL;
+	}
+
+	msg[0] = addr;
+	msg[1] = val;
+	ret = i2c_master_send(aat2870->client, msg, 2);
+	if (ret < 0)
+		return ret;
+	if (ret != 2)
+		return -EIO;
+
+	aat2870->reg_cache[addr].value = val;
+
+	dev_dbg(aat2870->dev, "write: addr=0x%02x, val=0x%02x\n", addr, val);
+	return 0;
+}
+
+static int aat2870_read(struct aat2870_data *aat2870, u8 addr, u8 *val)
+{
+	int ret;
+
+	mutex_lock(&aat2870->io_lock);
+	ret = __aat2870_read(aat2870, addr, val);
+	mutex_unlock(&aat2870->io_lock);
+
+	return ret;
+}
+
+static int aat2870_write(struct aat2870_data *aat2870, u8 addr, u8 val)
+{
+	int ret;
+
+	mutex_lock(&aat2870->io_lock);
+	ret = __aat2870_write(aat2870, addr, val);
+	mutex_unlock(&aat2870->io_lock);
+
+	return ret;
+}
+
+static int aat2870_update(struct aat2870_data *aat2870, u8 addr, u8 mask,
+			  u8 val)
+{
+	int change;
+	u8 old_val, new_val;
+	int ret;
+
+	mutex_lock(&aat2870->io_lock);
+
+	ret = __aat2870_read(aat2870, addr, &old_val);
+	if (ret)
+		goto out_unlock;
+
+	new_val = (old_val & ~mask) | (val & mask);
+	change = old_val != new_val;
+	if (change)
+		ret = __aat2870_write(aat2870, addr, new_val);
+
+out_unlock:
+	mutex_unlock(&aat2870->io_lock);
+
+	return ret;
+}
+
+static inline void aat2870_enable(struct aat2870_data *aat2870)
+{
+	if (aat2870->en_pin >= 0)
+		gpio_set_value(aat2870->en_pin, 1);
+
+	aat2870->is_enable = 1;
+}
+
+static inline void aat2870_disable(struct aat2870_data *aat2870)
+{
+	if (aat2870->en_pin >= 0)
+		gpio_set_value(aat2870->en_pin, 0);
+
+	aat2870->is_enable = 0;
+}
+
+#ifdef CONFIG_DEBUG_FS
+static ssize_t aat2870_dump_reg(struct aat2870_data *aat2870, char *buf)
+{
+	u8 addr, val;
+	ssize_t count = 0;
+	int ret;
+
+	count += sprintf(buf, "aat2870 registers\n");
+	for (addr = 0; addr < AAT2870_REG_NUM; addr++) {
+		count += sprintf(buf + count, "0x%02x: ", addr);
+		if (count >= PAGE_SIZE - 1)
+			break;
+
+		ret = aat2870->read(aat2870, addr, &val);
+		if (ret == 0)
+			count += snprintf(buf + count, PAGE_SIZE - count,
+					  "0x%02x", val);
+		else
+			count += snprintf(buf + count, PAGE_SIZE - count,
+					  "<read fail: %d>", ret);
+
+		if (count >= PAGE_SIZE - 1)
+			break;
+
+		count += snprintf(buf + count, PAGE_SIZE - count, "\n");
+		if (count >= PAGE_SIZE - 1)
+			break;
+	}
+
+	/* Truncate count; min() would cause a warning */
+	if (count >= PAGE_SIZE)
+		count = PAGE_SIZE - 1;
+
+	return count;
+}
+
+static int aat2870_reg_open_file(struct inode *inode, struct file *file)
+{
+	file->private_data = inode->i_private;
+
+	return 0;
+}
+
+static ssize_t aat2870_reg_read_file(struct file *file, char __user *user_buf,
+				     size_t count, loff_t *ppos)
+{
+	struct aat2870_data *aat2870 = file->private_data;
+	char *buf;
+	ssize_t ret;
+
+	buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	ret = aat2870_dump_reg(aat2870, buf);
+	if (ret >= 0)
+		ret = simple_read_from_buffer(user_buf, count, ppos, buf, ret);
+
+	kfree(buf);
+
+	return ret;
+}
+
+static ssize_t aat2870_reg_write_file(struct file *file,
+				      const char __user *user_buf, size_t count,
+				      loff_t *ppos)
+{
+	struct aat2870_data *aat2870 = file->private_data;
+	char buf[32];
+	int buf_size;
+	char *start = buf;
+	unsigned long addr, val;
+	int ret;
+
+	buf_size = min(count, (sizeof(buf)-1));
+	if (copy_from_user(buf, user_buf, buf_size)) {
+		dev_err(aat2870->dev, "Failed to copy from user\n");
+		return -EFAULT;
+	}
+	buf[buf_size] = 0;
+
+	while (*start == ' ')
+		start++;
+
+	addr = simple_strtoul(start, &start, 16);
+	if (addr >= AAT2870_REG_NUM) {
+		dev_err(aat2870->dev, "Invalid address, 0x%lx\n", addr);
+		return -EINVAL;
+	}
+
+	while (*start == ' ')
+		start++;
+
+	if (strict_strtoul(start, 16, &val))
+		return -EINVAL;
+
+	ret = aat2870->write(aat2870, (u8)addr, (u8)val);
+	if (ret)
+		return ret;
+
+	return buf_size;
+}
+
+static const struct file_operations aat2870_reg_fops = {
+	.open = aat2870_reg_open_file,
+	.read = aat2870_reg_read_file,
+	.write = aat2870_reg_write_file,
+};
+
+static void aat2870_init_debugfs(struct aat2870_data *aat2870)
+{
+	aat2870->dentry_root = debugfs_create_dir("aat2870", NULL);
+	if (!aat2870->dentry_root) {
+		dev_warn(aat2870->dev,
+			 "Failed to create debugfs root directory\n");
+		return;
+	}
+
+	aat2870->dentry_reg = debugfs_create_file("regs", 0644,
+						  aat2870->dentry_root,
+						  aat2870, &aat2870_reg_fops);
+	if (!aat2870->dentry_reg)
+		dev_warn(aat2870->dev,
+			 "Failed to create debugfs register file\n");
+}
+
+static void aat2870_uninit_debugfs(struct aat2870_data *aat2870)
+{
+	debugfs_remove_recursive(aat2870->dentry_root);
+}
+#else
+static inline void aat2870_init_debugfs(struct aat2870_data *aat2870)
+{
+}
+
+static inline void aat2870_uninit_debugfs(struct aat2870_data *aat2870)
+{
+}
+#endif /* CONFIG_DEBUG_FS */
+
+static int aat2870_i2c_probe(struct i2c_client *client,
+			     const struct i2c_device_id *id)
+{
+	struct aat2870_platform_data *pdata = client->dev.platform_data;
+	struct aat2870_data *aat2870;
+	int i, j;
+	int ret = 0;
+
+	aat2870 = kzalloc(sizeof(struct aat2870_data), GFP_KERNEL);
+	if (!aat2870) {
+		dev_err(&client->dev,
+			"Failed to allocate memory for aat2870\n");
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	aat2870->dev = &client->dev;
+	dev_set_drvdata(aat2870->dev, aat2870);
+
+	aat2870->client = client;
+	i2c_set_clientdata(client, aat2870);
+
+	aat2870->reg_cache = aat2870_regs;
+
+	if (pdata->en_pin < 0)
+		aat2870->en_pin = -1;
+	else
+		aat2870->en_pin = pdata->en_pin;
+
+	aat2870->init = pdata->init;
+	aat2870->uninit = pdata->uninit;
+	aat2870->read = aat2870_read;
+	aat2870->write = aat2870_write;
+	aat2870->update = aat2870_update;
+
+	mutex_init(&aat2870->io_lock);
+
+	if (aat2870->init)
+		aat2870->init(aat2870);
+
+	if (aat2870->en_pin >= 0) {
+		ret = gpio_request(aat2870->en_pin, "aat2870-en");
+		if (ret < 0) {
+			dev_err(&client->dev,
+				"Failed to request GPIO %d\n", aat2870->en_pin);
+			goto out_kfree;
+		}
+		gpio_direction_output(aat2870->en_pin, 1);
+	}
+
+	aat2870_enable(aat2870);
+
+	for (i = 0; i < pdata->num_subdevs; i++) {
+		for (j = 0; j < ARRAY_SIZE(aat2870_devs); j++) {
+			if ((pdata->subdevs[i].id == aat2870_devs[j].id) &&
+					!strcmp(pdata->subdevs[i].name,
+						aat2870_devs[j].name)) {
+				aat2870_devs[j].platform_data =
+					pdata->subdevs[i].platform_data;
+				break;
+			}
+		}
+	}
+
+	ret = mfd_add_devices(aat2870->dev, 0, aat2870_devs,
+			      ARRAY_SIZE(aat2870_devs), NULL, 0);
+	if (ret != 0) {
+		dev_err(aat2870->dev, "Failed to add subdev: %d\n", ret);
+		goto out_disable;
+	}
+
+	aat2870_init_debugfs(aat2870);
+
+	return 0;
+
+out_disable:
+	aat2870_disable(aat2870);
+	if (aat2870->en_pin >= 0)
+		gpio_free(aat2870->en_pin);
+out_kfree:
+	kfree(aat2870);
+out:
+	return ret;
+}
+
+static int aat2870_i2c_remove(struct i2c_client *client)
+{
+	struct aat2870_data *aat2870 = i2c_get_clientdata(client);
+
+	aat2870_uninit_debugfs(aat2870);
+
+	mfd_remove_devices(aat2870->dev);
+	aat2870_disable(aat2870);
+	if (aat2870->en_pin >= 0)
+		gpio_free(aat2870->en_pin);
+	if (aat2870->uninit)
+		aat2870->uninit(aat2870);
+	kfree(aat2870);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM
+static int aat2870_i2c_suspend(struct i2c_client *client, pm_message_t state)
+{
+	struct aat2870_data *aat2870 = i2c_get_clientdata(client);
+
+	aat2870_disable(aat2870);
+
+	return 0;
+}
+
+static int aat2870_i2c_resume(struct i2c_client *client)
+{
+	struct aat2870_data *aat2870 = i2c_get_clientdata(client);
+	struct aat2870_register *reg = NULL;
+	int i;
+
+	aat2870_enable(aat2870);
+
+	/* restore registers */
+	for (i = 0; i < AAT2870_REG_NUM; i++) {
+		reg = &aat2870->reg_cache[i];
+		if (reg->writeable)
+			aat2870->write(aat2870, i, reg->value);
+	}
+
+	return 0;
+}
+#else
+#define aat2870_i2c_suspend	NULL
+#define aat2870_i2c_resume	NULL
+#endif /* CONFIG_PM */
+
+static struct i2c_device_id aat2870_i2c_id_table[] = {
+	{ "aat2870", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, aat2870_i2c_id_table);
+
+static struct i2c_driver aat2870_i2c_driver = {
+	.driver = {
+		.name	= "aat2870",
+		.owner	= THIS_MODULE,
+	},
+	.probe		= aat2870_i2c_probe,
+	.remove		= aat2870_i2c_remove,
+	.suspend	= aat2870_i2c_suspend,
+	.resume		= aat2870_i2c_resume,
+	.id_table	= aat2870_i2c_id_table,
+};
+
+static int __init aat2870_init(void)
+{
+	return i2c_add_driver(&aat2870_i2c_driver);
+}
+subsys_initcall(aat2870_init);
+
+static void __exit aat2870_exit(void)
+{
+	i2c_del_driver(&aat2870_i2c_driver);
+}
+module_exit(aat2870_exit);
+
+MODULE_DESCRIPTION("Core support for the AnalogicTech AAT2870");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Jin Park <jinyoungp@nvidia.com>");

include/linux/mfd/aat2870.h

+/*
+ * linux/include/linux/mfd/aat2870.h
+ *
+ * Copyright (c) 2011, NVIDIA Corporation.
+ * Author: Jin Park <jinyoungp@nvidia.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA
+ */
+
+#ifndef __LINUX_MFD_AAT2870_H
+#define __LINUX_MFD_AAT2870_H
+
+#include <linux/debugfs.h>
+#include <linux/i2c.h>
+
+/* Register offsets */
+#define AAT2870_BL_CH_EN	0x00
+#define AAT2870_BLM		0x01
+#define AAT2870_BLS		0x02
+#define AAT2870_BL1		0x03
+#define AAT2870_BL2		0x04
+#define AAT2870_BL3		0x05
+#define AAT2870_BL4		0x06
+#define AAT2870_BL5		0x07
+#define AAT2870_BL6		0x08
+#define AAT2870_BL7		0x09
+#define AAT2870_BL8		0x0A
+#define AAT2870_FLR		0x0B
+#define AAT2870_FM		0x0C
+#define AAT2870_FS		0x0D
+#define AAT2870_ALS_CFG0	0x0E
+#define AAT2870_ALS_CFG1	0x0F
+#define AAT2870_ALS_CFG2	0x10
+#define AAT2870_AMB		0x11
+#define AAT2870_ALS0		0x12
+#define AAT2870_ALS1		0x13
+#define AAT2870_ALS2		0x14
+#define AAT2870_ALS3		0x15
+#define AAT2870_ALS4		0x16
+#define AAT2870_ALS5		0x17
+#define AAT2870_ALS6		0x18
+#define AAT2870_ALS7		0x19
+#define AAT2870_ALS8		0x1A
+#define AAT2870_ALS9		0x1B
+#define AAT2870_ALSA		0x1C
+#define AAT2870_ALSB		0x1D
+#define AAT2870_ALSC		0x1E
+#define AAT2870_ALSD		0x1F
+#define AAT2870_ALSE		0x20
+#define AAT2870_ALSF		0x21
+#define AAT2870_SUB_SET		0x22
+#define AAT2870_SUB_CTRL	0x23
+#define AAT2870_LDO_AB		0x24
+#define AAT2870_LDO_CD		0x25
+#define AAT2870_LDO_EN		0x26
+#define AAT2870_REG_NUM		0x27
+
+/* Device IDs */
+enum aat2870_id {
+	AAT2870_ID_BL,
+	AAT2870_ID_LDOA,
+	AAT2870_ID_LDOB,
+	AAT2870_ID_LDOC,
+	AAT2870_ID_LDOD
+};
+
+/* Backlight channels */
+#define AAT2870_BL_CH1		0x01
+#define AAT2870_BL_CH2		0x02
+#define AAT2870_BL_CH3		0x04
+#define AAT2870_BL_CH4		0x08
+#define AAT2870_BL_CH5		0x10
+#define AAT2870_BL_CH6		0x20
+#define AAT2870_BL_CH7		0x40
+#define AAT2870_BL_CH8		0x80
+#define AAT2870_BL_CH_ALL	0xFF
+
+/* Backlight current magnitude (mA) */
+enum aat2870_current {
+	AAT2870_CURRENT_0_45,
+	AAT2870_CURRENT_0_90,
+	AAT2870_CURRENT_1_80,
+	AAT2870_CURRENT_2_70,
+	AAT2870_CURRENT_3_60,
+	AAT2870_CURRENT_4_50,
+	AAT2870_CURRENT_5_40,
+	AAT2870_CURRENT_6_30,
+	AAT2870_CURRENT_7_20,
+	AAT2870_CURRENT_8_10,
+	AAT2870_CURRENT_9_00,
+	AAT2870_CURRENT_9_90,
+	AAT2870_CURRENT_10_8,
+	AAT2870_CURRENT_11_7,
+	AAT2870_CURRENT_12_6,
+	AAT2870_CURRENT_13_5,
+	AAT2870_CURRENT_14_4,
+	AAT2870_CURRENT_15_3,
+	AAT2870_CURRENT_16_2,
+	AAT2870_CURRENT_17_1,
+	AAT2870_CURRENT_18_0,
+	AAT2870_CURRENT_18_9,
+	AAT2870_CURRENT_19_8,
+	AAT2870_CURRENT_20_7,
+	AAT2870_CURRENT_21_6,
+	AAT2870_CURRENT_22_5,
+	AAT2870_CURRENT_23_4,
+	AAT2870_CURRENT_24_3,
+	AAT2870_CURRENT_25_2,
+	AAT2870_CURRENT_26_1,
+	AAT2870_CURRENT_27_0,
+	AAT2870_CURRENT_27_9
+};
+
+struct aat2870_register {
+	bool readable;
+	bool writeable;
+	u8 value;
+};
+
+struct aat2870_data {
+	struct device *dev;
+	struct i2c_client *client;
+
+	struct mutex io_lock;
+	struct aat2870_register *reg_cache; /* register cache */
+	int en_pin; /* enable GPIO pin (if < 0, ignore this value) */
+	bool is_enable;
+
+	/* init and uninit for platform specified */
+	int (*init)(struct aat2870_data *aat2870);
+	void (*uninit)(struct aat2870_data *aat2870);
+
+	/* i2c io funcntions */
+	int (*read)(struct aat2870_data *aat2870, u8 addr, u8 *val);
+	int (*write)(struct aat2870_data *aat2870, u8 addr, u8 val);
+	int (*update)(struct aat2870_data *aat2870, u8 addr, u8 mask, u8 val);
+
+	/* for debugfs */
+	struct dentry *dentry_root;
+	struct dentry *dentry_reg;
+};
+
+struct aat2870_subdev_info {
+	int id;
+	const char *name;
+	void *platform_data;
+};
+
+struct aat2870_platform_data {
+	int en_pin; /* enable GPIO pin (if < 0, ignore this value) */
+
+	struct aat2870_subdev_info *subdevs;
+	int num_subdevs;
+
+	/* init and uninit for platform specified */
+	int (*init)(struct aat2870_data *aat2870);
+	void (*uninit)(struct aat2870_data *aat2870);
+};
+
+struct aat2870_bl_platform_data {
+	/* backlight channels, default is AAT2870_BL_CH_ALL */
+	int channels;
+	/* backlight current magnitude, default is AAT2870_CURRENT_27_9 */
+	int max_current;
+	/* maximum brightness, default is 255 */
+	int max_brightness;
+};
+
+#endif /* __LINUX_MFD_AAT2870_H */