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    Subject[PATCHv3] support for AD5820 camera auto-focus coil
    This adds support for AD5820 autofocus coil, found for example in
    Nokia N900 smartphone.

    Signed-off-by: Pavel Machek <pavel@ucw.cz>

    ---
    v2: simple cleanups, fix error paths, simplify probe

    v3: more cleanups, remove printk, add include

    diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
    index 993dc50..77313a1 100644
    --- a/drivers/media/i2c/Kconfig
    +++ b/drivers/media/i2c/Kconfig
    @@ -279,6 +279,13 @@ config VIDEO_ML86V7667
    To compile this driver as a module, choose M here: the
    module will be called ml86v7667.

    +config VIDEO_AD5820
    + tristate "AD5820 lens voice coil support"
    + depends on I2C && VIDEO_V4L2 && MEDIA_CONTROLLER
    + ---help---
    + This is a driver for the AD5820 camera lens voice coil.
    + It is used for example in Nokia N900 (RX-51).
    +
    config VIDEO_SAA7110
    tristate "Philips SAA7110 video decoder"
    depends on VIDEO_V4L2 && I2C
    diff --git a/drivers/media/i2c/Makefile b/drivers/media/i2c/Makefile
    index 94f2c99..34434ae 100644
    --- a/drivers/media/i2c/Makefile
    +++ b/drivers/media/i2c/Makefile
    @@ -19,6 +20,7 @@ obj-$(CONFIG_VIDEO_SAA717X) += saa717x.o
    obj-$(CONFIG_VIDEO_SAA7127) += saa7127.o
    obj-$(CONFIG_VIDEO_SAA7185) += saa7185.o
    obj-$(CONFIG_VIDEO_SAA6752HS) += saa6752hs.o
    +obj-$(CONFIG_VIDEO_AD5820) += ad5820.o
    obj-$(CONFIG_VIDEO_ADV7170) += adv7170.o
    obj-$(CONFIG_VIDEO_ADV7175) += adv7175.o
    obj-$(CONFIG_VIDEO_ADV7180) += adv7180.o
    diff --git a/drivers/media/i2c/ad5820.c b/drivers/media/i2c/ad5820.c
    new file mode 100644
    index 0000000..7725829
    --- /dev/null
    +++ b/drivers/media/i2c/ad5820.c
    @@ -0,0 +1,416 @@
    +/*
    + * drivers/media/i2c/ad5820.c
    + *
    + * AD5820 DAC driver for camera voice coil focus.
    + *
    + * Copyright (C) 2008 Nokia Corporation
    + * Copyright (C) 2007 Texas Instruments
    + * Copyright (C) 2016 Pavel Machek <pavel@ucw.cz>
    + *
    + * Contact: Tuukka Toivonen
    + * Sakari Ailus
    + *
    + * Based on af_d88.c by Texas Instruments.
    + *
    + * 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/module.h>
    +#include <linux/errno.h>
    +#include <linux/i2c.h>
    +#include <linux/slab.h>
    +#include <linux/sched.h>
    +#include <linux/delay.h>
    +#include <linux/bitops.h>
    +#include <linux/kernel.h>
    +#include <linux/regulator/consumer.h>
    +
    +#include <media/ad5820.h>
    +#include <media/v4l2-device.h>
    +
    +#define CODE_TO_RAMP_US(s) ((s) == 0 ? 0 : (1 << ((s) - 1)) * 50)
    +#define RAMP_US_TO_CODE(c) fls(((c) + ((c)>>1)) / 50)
    +
    +/**
    + * @brief I2C write using i2c_transfer().
    + * @param coil - the driver data structure
    + * @param data - register value to be written
    + * @returns nonnegative on success, negative if failed
    + */
    +static int ad5820_write(struct ad5820_device *coil, u16 data)
    +{
    + struct i2c_client *client = v4l2_get_subdevdata(&coil->subdev);
    + struct i2c_msg msg;
    + int r;
    +
    + if (!client->adapter)
    + return -ENODEV;
    +
    + data = cpu_to_be16(data);
    + msg.addr = client->addr;
    + msg.flags = 0;
    + msg.len = 2;
    + msg.buf = (u8 *)&data;
    +
    + r = i2c_transfer(client->adapter, &msg, 1);
    + if (r < 0) {
    + dev_err(&client->dev, "write failed, error %d\n", r);
    + return r;
    + }
    +
    + return 0;
    +}
    +
    +/*
    + * Calculate status word and write it to the device based on current
    + * values of V4L2 controls. It is assumed that the stored V4L2 control
    + * values are properly limited and rounded.
    + */
    +static int ad5820_update_hw(struct ad5820_device *coil)
    +{
    + u16 status;
    +
    + status = RAMP_US_TO_CODE(coil->focus_ramp_time);
    + status |= coil->focus_ramp_mode
    + ? AD5820_RAMP_MODE_64_16 : AD5820_RAMP_MODE_LINEAR;
    + status |= coil->focus_absolute << AD5820_DAC_SHIFT;
    +
    + if (coil->standby)
    + status |= AD5820_POWER_DOWN;
    +
    + return ad5820_write(coil, status);
    +}
    +
    +/*
    + * Power handling
    + */
    +static int ad5820_power_off(struct ad5820_device *coil, int standby)
    +{
    + int ret = 0;
    +
    + /*
    + * Go to standby first as real power off my be denied by the hardware
    + * (single power line control for both coil and sensor).
    + */
    + if (standby) {
    + coil->standby = 1;
    + ret = ad5820_update_hw(coil);
    + }
    +
    + ret |= regulator_disable(coil->vana);
    +
    + return ret;
    +}
    +
    +static int ad5820_power_on(struct ad5820_device *coil, int restore)
    +{
    + int ret;
    +
    + printk("ad5820_power_on: 1\n");
    + ret = regulator_enable(coil->vana);
    + if (ret < 0)
    + return ret;
    +
    + if (restore) {
    + /* Restore the hardware settings. */
    + coil->standby = 0;
    + ret = ad5820_update_hw(coil);
    + if (ret)
    + goto fail;
    + }
    + return 0;
    +
    +fail:
    + coil->standby = 1;
    + regulator_disable(coil->vana);
    +
    + return ret;
    +}
    +
    +/*
    + * V4L2 controls
    + */
    +static int ad5820_set_ctrl(struct v4l2_ctrl *ctrl)
    +{
    + struct ad5820_device *coil =
    + container_of(ctrl->handler, struct ad5820_device, ctrls);
    + u32 code;
    +
    + switch (ctrl->id) {
    + case V4L2_CID_FOCUS_ABSOLUTE:
    + coil->focus_absolute = ctrl->val;
    + return ad5820_update_hw(coil);
    +
    + case V4L2_CID_FOCUS_AD5820_RAMP_TIME:
    + code = RAMP_US_TO_CODE(ctrl->val);
    + ctrl->val = CODE_TO_RAMP_US(code);
    + coil->focus_ramp_time = ctrl->val;
    + break;
    +
    + case V4L2_CID_FOCUS_AD5820_RAMP_MODE:
    + coil->focus_ramp_mode = ctrl->val;
    + break;
    + }
    +
    + return 0;
    +}
    +
    +static const struct v4l2_ctrl_ops ad5820_ctrl_ops = {
    + .s_ctrl = ad5820_set_ctrl,
    +};
    +
    +static const char *ad5820_focus_menu[] = {
    + "Linear ramp",
    + "64/16 ramp",
    +};
    +
    +static const struct v4l2_ctrl_config ad5820_ctrls[] = {
    + {
    + .ops = &ad5820_ctrl_ops,
    + .id = V4L2_CID_FOCUS_AD5820_RAMP_TIME,
    + .type = V4L2_CTRL_TYPE_INTEGER,
    + .name = "Focus ramping time [us]",
    + .min = 0,
    + .max = 3200,
    + .step = 50,
    + .def = 0,
    + .flags = 0,
    + },
    + {
    + .ops = &ad5820_ctrl_ops,
    + .id = V4L2_CID_FOCUS_AD5820_RAMP_MODE,
    + .type = V4L2_CTRL_TYPE_MENU,
    + .name = "Focus ramping mode",
    + .min = 0,
    + .max = ARRAY_SIZE(ad5820_focus_menu),
    + .step = 0,
    + .def = 0,
    + .flags = 0,
    + .qmenu = ad5820_focus_menu,
    + },
    +};
    +
    +
    +static int ad5820_init_controls(struct ad5820_device *coil)
    +{
    + unsigned int i;
    +
    + v4l2_ctrl_handler_init(&coil->ctrls, ARRAY_SIZE(ad5820_ctrls) + 1);
    +
    + /*
    + * V4L2_CID_FOCUS_ABSOLUTE
    + *
    + * Minimum current is 0 mA, maximum is 100 mA. Thus, 1 code is
    + * equivalent to 100/1023 = 0.0978 mA. Nevertheless, we do not use [mA]
    + * for focus position, because it is meaningless for user. Meaningful
    + * would be to use focus distance or even its inverse, but since the
    + * driver doesn't have sufficiently knowledge to do the conversion, we
    + * will just use abstract codes here. In any case, smaller value = focus
    + * position farther from camera. The default zero value means focus at
    + * infinity, and also least current consumption.
    + */
    + v4l2_ctrl_new_std(&coil->ctrls, &ad5820_ctrl_ops,
    + V4L2_CID_FOCUS_ABSOLUTE, 0, 1023, 1, 0);
    +
    + /* V4L2_CID_TEST_PATTERN and V4L2_CID_MODE_* */
    + for (i = 0; i < ARRAY_SIZE(ad5820_ctrls); ++i)
    + v4l2_ctrl_new_custom(&coil->ctrls, &ad5820_ctrls[i], NULL);
    +
    + if (coil->ctrls.error)
    + return coil->ctrls.error;
    +
    + coil->focus_absolute = 0;
    + coil->focus_ramp_time = 0;
    + coil->focus_ramp_mode = 0;
    +
    + coil->subdev.ctrl_handler = &coil->ctrls;
    + return 0;
    +}
    +
    +/*
    + * V4L2 subdev operations
    + */
    +static int ad5820_registered(struct v4l2_subdev *subdev)
    +{
    + struct ad5820_device *coil = to_ad5820_device(subdev);
    + struct i2c_client *client = v4l2_get_subdevdata(subdev);
    +
    + coil->vana = regulator_get(&client->dev, "VANA");
    + if (IS_ERR(coil->vana)) {
    + dev_err(&client->dev, "could not get regulator for vana\n");
    + return -ENODEV;
    + }
    +
    + return ad5820_init_controls(coil);
    +}
    +
    +static int
    +ad5820_set_power(struct v4l2_subdev *subdev, int on)
    +{
    + struct ad5820_device *coil = to_ad5820_device(subdev);
    + int ret = 0;
    +
    + mutex_lock(&coil->power_lock);
    +
    + /*
    + * If the power count is modified from 0 to != 0 or from != 0 to 0,
    + * update the power state.
    + */
    + if (coil->power_count == !on) {
    + ret = on ? ad5820_power_on(coil, 1) : ad5820_power_off(coil, 1);
    + if (ret < 0)
    + goto done;
    + }
    +
    + /* Update the power count. */
    + coil->power_count += on ? 1 : -1;
    + WARN_ON(coil->power_count < 0);
    +
    +done:
    + mutex_unlock(&coil->power_lock);
    + return ret;
    +}
    +
    +static int ad5820_open(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
    +{
    + return ad5820_set_power(sd, 1);
    +}
    +
    +static int ad5820_close(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
    +{
    + return ad5820_set_power(sd, 0);
    +}
    +
    +static const struct v4l2_subdev_core_ops ad5820_core_ops = {
    + .s_power = ad5820_set_power,
    +};
    +
    +static const struct v4l2_subdev_ops ad5820_ops = {
    + .core = &ad5820_core_ops,
    +};
    +
    +static const struct v4l2_subdev_internal_ops ad5820_internal_ops = {
    + .registered = ad5820_registered,
    + .open = ad5820_open,
    + .close = ad5820_close,
    +};
    +
    +/*
    + * I2C driver
    + */
    +#ifdef CONFIG_PM
    +
    +static int ad5820_suspend(struct device *dev)
    +{
    + struct i2c_client *client = container_of(dev, struct i2c_client, dev);
    + struct v4l2_subdev *subdev = i2c_get_clientdata(client);
    + struct ad5820_device *coil = to_ad5820_device(subdev);
    +
    + if (!coil->power_count)
    + return 0;
    +
    + return ad5820_power_off(coil, 0);
    +}
    +
    +static int ad5820_resume(struct device *dev)
    +{
    + struct i2c_client *client = container_of(dev, struct i2c_client, dev);
    + struct v4l2_subdev *subdev = i2c_get_clientdata(client);
    + struct ad5820_device *coil = to_ad5820_device(subdev);
    +
    + if (!coil->power_count)
    + return 0;
    +
    + return ad5820_power_on(coil, 1);
    +}
    +
    +#else
    +
    +#define ad5820_suspend NULL
    +#define ad5820_resume NULL
    +
    +#endif /* CONFIG_PM */
    +
    +static int ad5820_probe(struct i2c_client *client,
    + const struct i2c_device_id *devid)
    +{
    + struct ad5820_device *coil;
    + int ret = 0;
    +
    + coil = kzalloc(sizeof(*coil), GFP_KERNEL);
    + if (coil == NULL)
    + return -ENOMEM;
    +
    + mutex_init(&coil->power_lock);
    +
    + v4l2_i2c_subdev_init(&coil->subdev, client, &ad5820_ops);
    + coil->subdev.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
    + coil->subdev.internal_ops = &ad5820_internal_ops;
    + strcpy(coil->subdev.name, "ad5820 focus");
    +
    + ret = media_entity_pads_init(&coil->subdev.entity, 0, NULL);
    + if (ret < 0)
    + goto free;
    +
    + ret = v4l2_async_register_subdev(&coil->subdev);
    + if (ret < 0)
    + goto cleanup;
    +
    + return ret;
    +cleanup:
    + media_entity_cleanup(&coil->subdev.entity);
    +free:
    + kfree(coil);
    + return ret;
    +}
    +
    +static int __exit ad5820_remove(struct i2c_client *client)
    +{
    + struct v4l2_subdev *subdev = i2c_get_clientdata(client);
    + struct ad5820_device *coil = to_ad5820_device(subdev);
    +
    + v4l2_device_unregister_subdev(&coil->subdev);
    + v4l2_ctrl_handler_free(&coil->ctrls);
    + media_entity_cleanup(&coil->subdev.entity);
    + if (coil->vana)
    + regulator_put(coil->vana);
    +
    + kfree(coil);
    + return 0;
    +}
    +
    +static const struct i2c_device_id ad5820_id_table[] = {
    + { AD5820_NAME, 0 },
    + { }
    +};
    +MODULE_DEVICE_TABLE(i2c, ad5820_id_table);
    +
    +static SIMPLE_DEV_PM_OPS(ad5820_pm, ad5820_suspend, ad5820_resume);
    +
    +static struct i2c_driver ad5820_i2c_driver = {
    + .driver = {
    + .name = AD5820_NAME,
    + .pm = &ad5820_pm,
    + },
    + .probe = ad5820_probe,
    + .remove = __exit_p(ad5820_remove),
    + .id_table = ad5820_id_table,
    +};
    +
    +module_i2c_driver(ad5820_i2c_driver);
    +
    +MODULE_AUTHOR("Tuukka Toivonen");
    +MODULE_DESCRIPTION("AD5820 camera lens driver");
    +MODULE_LICENSE("GPL");
    diff --git a/include/media/ad5820.h b/include/media/ad5820.h
    new file mode 100644
    index 0000000..f5a1565
    --- /dev/null
    +++ b/include/media/ad5820.h
    @@ -0,0 +1,70 @@
    +/*
    + * include/media/ad5820.h
    + *
    + * Copyright (C) 2008 Nokia Corporation
    + * Copyright (C) 2007 Texas Instruments
    + *
    + * Contact: Tuukka Toivonen <tuukka.o.toivonen@nokia.com>
    + * Sakari Ailus <sakari.ailus@nokia.com>
    + *
    + * Based on af_d88.c by Texas Instruments.
    + *
    + * 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 AD5820_H
    +#define AD5820_H
    +
    +#include <linux/i2c.h>
    +#include <linux/mutex.h>
    +#include <linux/videodev2.h>
    +
    +#include <media/v4l2-ctrls.h>
    +#include <media/v4l2-subdev.h>
    +
    +struct regulator;
    +
    +#define AD5820_NAME "ad5820"
    +#define AD5820_I2C_ADDR (0x18 >> 1)
    +
    +/* Register definitions */
    +#define AD5820_POWER_DOWN (1 << 15)
    +#define AD5820_DAC_SHIFT 4
    +#define AD5820_RAMP_MODE_LINEAR (0 << 3)
    +#define AD5820_RAMP_MODE_64_16 (1 << 3)
    +
    +struct ad5820_platform_data {
    + int (*set_xshutdown)(struct v4l2_subdev *subdev, int set);
    +};
    +
    +#define to_ad5820_device(sd) container_of(sd, struct ad5820_device, subdev)
    +
    +struct ad5820_device {
    + struct v4l2_subdev subdev;
    + struct ad5820_platform_data *platform_data;
    + struct regulator *vana;
    +
    + struct v4l2_ctrl_handler ctrls;
    + u32 focus_absolute;
    + u32 focus_ramp_time;
    + u32 focus_ramp_mode;
    +
    + struct mutex power_lock;
    + int power_count;
    +
    + int standby : 1;
    +};
    +
    +#endif /* AD5820_H */


    --
    (english) http://www.livejournal.com/~pavelmachek
    (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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