Re: [PATCHv3] support for AD5820 camera auto-focus coil

From: Ivaylo Dimitrov
Date: Sat May 21 2016 - 07:43:56 EST

Hi,

On 21.05.2016 13:56, Pavel Machek wrote:
This adds support for AD5820 autofocus coil, found for example in
Nokia N900 smartphone.

Signed-off-by: Pavel Machek <pavel@xxxxxx>

---
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@xxxxxx>
+ *
+ * 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
+ */
+

At least on my machine checkpatch.pl complains about FSF address.

+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/i2c.h>
+#include <linux/slab.h>
+#include <linux/sched.h>
+#include <linux/delay.h>

Doesn't seem to get used.

+#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");

devm_regulator_get()?

+ 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);

devm_kzalloc() ?

+ 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@xxxxxxxxx>
+ * Sakari Ailus <sakari.ailus@xxxxxxxxx>
+ *
+ * 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

Do those defines really belong here? Isn't it better if they are moved to ad5820.c?

+#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;
+};
+

The same for struct ad5820_device, is it really part of the public API?

+#endif /* AD5820_H */