/*
 * 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/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 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];
        ssize_t buf_size;
        char *start = buf;
        unsigned long addr, val;
        int ret;

        buf_size = min(count, (size_t)(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++;

        ret = kstrtoul(start, 16, &addr);
        if (ret)
                return ret;

        if (addr >= AAT2870_REG_NUM) {
                dev_err(aat2870->dev, "Invalid address, 0x%lx\n", addr);
                return -EINVAL;
        }

        while (*start == ' ')
                start++;

        ret = kstrtoul(start, 16, &val);
        if (ret)
                return ret;

        ret = aat2870->write(aat2870, (u8)addr, (u8)val);
        if (ret)
                return ret;

        return buf_size;
}

static const struct file_operations aat2870_reg_fops = {
        .open = simple_open,
        .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");
}

#else
static inline void aat2870_init_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 = dev_get_platdata(&client->dev);
        struct aat2870_data *aat2870;
        int i, j;
        int ret = 0;

        aat2870 = devm_kzalloc(&client->dev, sizeof(struct aat2870_data),
                                GFP_KERNEL);
        if (!aat2870)
                return -ENOMEM;

        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 = devm_gpio_request_one(&client->dev, aat2870->en_pin,
                                        GPIOF_OUT_INIT_HIGH, "aat2870-en");
                if (ret < 0) {
                        dev_err(&client->dev,
                                "Failed to request GPIO %d\n", aat2870->en_pin);
                        return ret;
                }
        }

        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, NULL);
        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);
        return ret;
}

#ifdef CONFIG_PM_SLEEP
static int aat2870_i2c_suspend(struct device *dev)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct aat2870_data *aat2870 = i2c_get_clientdata(client);

        aat2870_disable(aat2870);

        return 0;
}

static int aat2870_i2c_resume(struct device *dev)
{
        struct i2c_client *client = to_i2c_client(dev);
        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;
}
#endif /* CONFIG_PM_SLEEP */

static SIMPLE_DEV_PM_OPS(aat2870_pm_ops, aat2870_i2c_suspend,
                         aat2870_i2c_resume);

static const struct i2c_device_id aat2870_i2c_id_table[] = {
        { "aat2870", 0 },
        { }
};

static struct i2c_driver aat2870_i2c_driver = {
        .driver = {
                .name                   = "aat2870",
                .pm                     = &aat2870_pm_ops,
                .suppress_bind_attrs    = true,
        },
        .probe          = aat2870_i2c_probe,
        .id_table       = aat2870_i2c_id_table,
};

static int __init aat2870_init(void)
{
        return i2c_add_driver(&aat2870_i2c_driver);
}
subsys_initcall(aat2870_init);