// SPDX-License-Identifier: GPL-2.0
// Copyright (C) 2018 Intel Corporation

#include <linux/acpi.h>
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/iopoll.h>
#include <linux/module.h>
#include <linux/pm_runtime.h>
#include <media/v4l2-ctrls.h>
#include <media/v4l2-device.h>

#define DW9807_MAX_FOCUS_POS    1023
/*
 * This sets the minimum granularity for the focus positions.
 * A value of 1 gives maximum accuracy for a desired focus position.
 */
#define DW9807_FOCUS_STEPS      1
/*
 * This acts as the minimum granularity of lens movement.
 * Keep this value power of 2, so the control steps can be
 * uniformly adjusted for gradual lens movement, with desired
 * number of control steps.
 */
#define DW9807_CTRL_STEPS       16
#define DW9807_CTRL_DELAY_US    1000

#define DW9807_CTL_ADDR         0x02
/*
 * DW9807 separates two registers to control the VCM position.
 * One for MSB value, another is LSB value.
 */
#define DW9807_MSB_ADDR         0x03
#define DW9807_LSB_ADDR         0x04
#define DW9807_STATUS_ADDR      0x05
#define DW9807_MODE_ADDR        0x06
#define DW9807_RESONANCE_ADDR   0x07

#define MAX_RETRY               10

struct dw9807_device {
        struct v4l2_ctrl_handler ctrls_vcm;
        struct v4l2_subdev sd;
        u16 current_val;
};

static inline struct dw9807_device *sd_to_dw9807_vcm(
                                        struct v4l2_subdev *subdev)
{
        return container_of(subdev, struct dw9807_device, sd);
}

static int dw9807_i2c_check(struct i2c_client *client)
{
        const char status_addr = DW9807_STATUS_ADDR;
        char status_result;
        int ret;

        ret = i2c_master_send(client, &status_addr, sizeof(status_addr));
        if (ret < 0) {
                dev_err(&client->dev, "I2C write STATUS address fail ret = %d\n",
                        ret);
                return ret;
        }

        ret = i2c_master_recv(client, &status_result, sizeof(status_result));
        if (ret < 0) {
                dev_err(&client->dev, "I2C read STATUS value fail ret = %d\n",
                        ret);
                return ret;
        }

        return status_result;
}

static int dw9807_set_dac(struct i2c_client *client, u16 data)
{
        const char tx_data[3] = {
                DW9807_MSB_ADDR, ((data >> 8) & 0x03), (data & 0xff)
        };
        int val, ret;

        /*
         * According to the datasheet, need to check the bus status before we
         * write VCM position. This ensure that we really write the value
         * into the register
         */
        ret = readx_poll_timeout(dw9807_i2c_check, client, val, val <= 0,
                        DW9807_CTRL_DELAY_US, MAX_RETRY * DW9807_CTRL_DELAY_US);

        if (ret || val < 0) {
                if (ret) {
                        dev_warn(&client->dev,
                                "Cannot do the write operation because VCM is busy\n");
                }

                return ret ? -EBUSY : val;
        }

        /* Write VCM position to registers */
        ret = i2c_master_send(client, tx_data, sizeof(tx_data));
        if (ret < 0) {
                dev_err(&client->dev,
                        "I2C write MSB fail ret=%d\n", ret);

                return ret;
        }

        return 0;
}

static int dw9807_set_ctrl(struct v4l2_ctrl *ctrl)
{
        struct dw9807_device *dev_vcm = container_of(ctrl->handler,
                struct dw9807_device, ctrls_vcm);

        if (ctrl->id == V4L2_CID_FOCUS_ABSOLUTE) {
                struct i2c_client *client = v4l2_get_subdevdata(&dev_vcm->sd);

                dev_vcm->current_val = ctrl->val;
                return dw9807_set_dac(client, ctrl->val);
        }

        return -EINVAL;
}

static const struct v4l2_ctrl_ops dw9807_vcm_ctrl_ops = {
        .s_ctrl = dw9807_set_ctrl,
};

static int dw9807_open(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
{
        return pm_runtime_resume_and_get(sd->dev);
}

static int dw9807_close(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
{
        pm_runtime_put(sd->dev);

        return 0;
}

static const struct v4l2_subdev_internal_ops dw9807_int_ops = {
        .open = dw9807_open,
        .close = dw9807_close,
};

static const struct v4l2_subdev_ops dw9807_ops = { };

static void dw9807_subdev_cleanup(struct dw9807_device *dw9807_dev)
{
        v4l2_async_unregister_subdev(&dw9807_dev->sd);
        v4l2_ctrl_handler_free(&dw9807_dev->ctrls_vcm);
        media_entity_cleanup(&dw9807_dev->sd.entity);
}

static int dw9807_init_controls(struct dw9807_device *dev_vcm)
{
        struct v4l2_ctrl_handler *hdl = &dev_vcm->ctrls_vcm;
        const struct v4l2_ctrl_ops *ops = &dw9807_vcm_ctrl_ops;
        struct i2c_client *client = v4l2_get_subdevdata(&dev_vcm->sd);

        v4l2_ctrl_handler_init(hdl, 1);

        v4l2_ctrl_new_std(hdl, ops, V4L2_CID_FOCUS_ABSOLUTE,
                          0, DW9807_MAX_FOCUS_POS, DW9807_FOCUS_STEPS, 0);

        dev_vcm->sd.ctrl_handler = hdl;
        if (hdl->error) {
                dev_err(&client->dev, "%s fail error: 0x%x\n",
                        __func__, hdl->error);
                return hdl->error;
        }

        return 0;
}

static int dw9807_probe(struct i2c_client *client)
{
        struct dw9807_device *dw9807_dev;
        int rval;

        dw9807_dev = devm_kzalloc(&client->dev, sizeof(*dw9807_dev),
                                  GFP_KERNEL);
        if (dw9807_dev == NULL)
                return -ENOMEM;

        v4l2_i2c_subdev_init(&dw9807_dev->sd, client, &dw9807_ops);
        dw9807_dev->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
        dw9807_dev->sd.internal_ops = &dw9807_int_ops;

        rval = dw9807_init_controls(dw9807_dev);
        if (rval)
                goto err_cleanup;

        rval = media_entity_pads_init(&dw9807_dev->sd.entity, 0, NULL);
        if (rval < 0)
                goto err_cleanup;

        dw9807_dev->sd.entity.function = MEDIA_ENT_F_LENS;

        rval = v4l2_async_register_subdev(&dw9807_dev->sd);
        if (rval < 0)
                goto err_cleanup;

        pm_runtime_set_active(&client->dev);
        pm_runtime_enable(&client->dev);
        pm_runtime_idle(&client->dev);

        return 0;

err_cleanup:
        v4l2_ctrl_handler_free(&dw9807_dev->ctrls_vcm);
        media_entity_cleanup(&dw9807_dev->sd.entity);

        return rval;
}

static void dw9807_remove(struct i2c_client *client)
{
        struct v4l2_subdev *sd = i2c_get_clientdata(client);
        struct dw9807_device *dw9807_dev = sd_to_dw9807_vcm(sd);

        pm_runtime_disable(&client->dev);

        dw9807_subdev_cleanup(dw9807_dev);
}

/*
 * This function sets the vcm position, so it consumes least current
 * The lens position is gradually moved in units of DW9807_CTRL_STEPS,
 * to make the movements smoothly.
 */
static int __maybe_unused dw9807_vcm_suspend(struct device *dev)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct v4l2_subdev *sd = i2c_get_clientdata(client);
        struct dw9807_device *dw9807_dev = sd_to_dw9807_vcm(sd);
        const char tx_data[2] = { DW9807_CTL_ADDR, 0x01 };
        int ret, val;

        for (val = dw9807_dev->current_val & ~(DW9807_CTRL_STEPS - 1);
             val >= 0; val -= DW9807_CTRL_STEPS) {
                ret = dw9807_set_dac(client, val);
                if (ret)
                        dev_err_once(dev, "%s I2C failure: %d", __func__, ret);
                usleep_range(DW9807_CTRL_DELAY_US, DW9807_CTRL_DELAY_US + 10);
        }

        /* Power down */
        ret = i2c_master_send(client, tx_data, sizeof(tx_data));
        if (ret < 0) {
                dev_err(&client->dev, "I2C write CTL fail ret = %d\n", ret);
                return ret;
        }

        return 0;
}

/*
 * This function sets the vcm position to the value set by the user
 * through v4l2_ctrl_ops s_ctrl handler
 * The lens position is gradually moved in units of DW9807_CTRL_STEPS,
 * to make the movements smoothly.
 */
static int  __maybe_unused dw9807_vcm_resume(struct device *dev)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct v4l2_subdev *sd = i2c_get_clientdata(client);
        struct dw9807_device *dw9807_dev = sd_to_dw9807_vcm(sd);
        const char tx_data[2] = { DW9807_CTL_ADDR, 0x00 };
        int ret, val;

        /* Power on */
        ret = i2c_master_send(client, tx_data, sizeof(tx_data));
        if (ret < 0) {
                dev_err(&client->dev, "I2C write CTL fail ret = %d\n", ret);
                return ret;
        }

        for (val = dw9807_dev->current_val % DW9807_CTRL_STEPS;
             val < dw9807_dev->current_val + DW9807_CTRL_STEPS - 1;
             val += DW9807_CTRL_STEPS) {
                ret = dw9807_set_dac(client, val);
                if (ret)
                        dev_err_ratelimited(dev, "%s I2C failure: %d",
                                                __func__, ret);
                usleep_range(DW9807_CTRL_DELAY_US, DW9807_CTRL_DELAY_US + 10);
        }

        return 0;
}

static const struct of_device_id dw9807_of_table[] = {
        { .compatible = "dongwoon,dw9807-vcm" },
        /* Compatibility for older firmware, NEVER USE THIS IN FIRMWARE! */
        { .compatible = "dongwoon,dw9807" },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, dw9807_of_table);

static const struct dev_pm_ops dw9807_pm_ops = {
        SET_SYSTEM_SLEEP_PM_OPS(dw9807_vcm_suspend, dw9807_vcm_resume)
        SET_RUNTIME_PM_OPS(dw9807_vcm_suspend, dw9807_vcm_resume, NULL)
};

static struct i2c_driver dw9807_i2c_driver = {
        .driver = {
                .name = "dw9807",
                .pm = &dw9807_pm_ops,
                .of_match_table = dw9807_of_table,
        },
        .probe = dw9807_probe,
        .remove = dw9807_remove,
};

module_i2c_driver(dw9807_i2c_driver);

MODULE_AUTHOR("Chiang, Alan");
MODULE_DESCRIPTION("DW9807 VCM driver");
MODULE_LICENSE("GPL v2");