[2/2] media: i2c: dw9768: Add DW9768 VCM driver
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Message ID 20190708100641.2702-3-dongchun.zhu@mediatek.com
State New
Headers show
Series
  • media: add support for DW9768 VCM driver
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Commit Message

Dongchun Zhu July 8, 2019, 10:06 a.m. UTC
From: Dongchun Zhu <dongchun.zhu@mediatek.com>

This patch adds a V4L2 sub-device driver for DW9768 lens voice coil,
and provides control to set the desired focus.

The DW9807 is a 10 bit DAC from Dongwoon, designed for linear
control of voice coil motor.

Signed-off-by: Dongchun Zhu <dongchun.zhu@mediatek.com>
---
 MAINTAINERS                |   1 +
 drivers/media/i2c/Kconfig  |  10 +
 drivers/media/i2c/Makefile |   1 +
 drivers/media/i2c/dw9768.c | 458 +++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 470 insertions(+)
 create mode 100644 drivers/media/i2c/dw9768.c

Comments

Bingbu Cao July 24, 2019, 3:16 a.m. UTC | #1
On 7/8/19 6:06 PM, dongchun.zhu@mediatek.com wrote:
> From: Dongchun Zhu <dongchun.zhu@mediatek.com>
> 
> This patch adds a V4L2 sub-device driver for DW9768 lens voice coil,
> and provides control to set the desired focus.
> 
> The DW9807 is a 10 bit DAC from Dongwoon, designed for linear
> control of voice coil motor.
> 
> Signed-off-by: Dongchun Zhu <dongchun.zhu@mediatek.com>
> ---
>  MAINTAINERS                |   1 +
>  drivers/media/i2c/Kconfig  |  10 +
>  drivers/media/i2c/Makefile |   1 +
>  drivers/media/i2c/dw9768.c | 458 +++++++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 470 insertions(+)
>  create mode 100644 drivers/media/i2c/dw9768.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 8f6ac93..17152d7 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -4877,6 +4877,7 @@ M:	Dongchun Zhu <dongchun.zhu@mediatek.com>
>  L:	linux-media@vger.kernel.org
>  T:	git git://linuxtv.org/media_tree.git
>  S:	Maintained
> +F:	drivers/media/i2c/dw9768.c
>  F:	Documentation/devicetree/bindings/media/i2c/dongwoon,dw9768.txt
>  
>  DONGWOON DW9807 LENS VOICE COIL DRIVER
> diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
> index 7793358..8ff6c95 100644
> --- a/drivers/media/i2c/Kconfig
> +++ b/drivers/media/i2c/Kconfig
> @@ -1014,6 +1014,16 @@ config VIDEO_DW9714
>  	  capability. This is designed for linear control of
>  	  voice coil motors, controlled via I2C serial interface.
>  
> +config VIDEO_DW9768
> +	tristate "DW9768 lens voice coil support"
> +	depends on I2C && VIDEO_V4L2 && MEDIA_CONTROLLER
> +	depends on VIDEO_V4L2_SUBDEV_API
> +	help
> +	  This is a driver for the DW9768 camera lens voice coil.
> +	  DW9768 is a 10 bit DAC with 100mA output current sink
> +	  capability. This is designed for linear control of
> +	  voice coil motors, controlled via I2C serial interface.
> +
>  config VIDEO_DW9807_VCM
>  	tristate "DW9807 lens voice coil support"
>  	depends on I2C && VIDEO_V4L2 && MEDIA_CONTROLLER
> diff --git a/drivers/media/i2c/Makefile b/drivers/media/i2c/Makefile
> index d8ad9da..944fbf6 100644
> --- a/drivers/media/i2c/Makefile
> +++ b/drivers/media/i2c/Makefile
> @@ -24,6 +24,7 @@ obj-$(CONFIG_VIDEO_SAA6752HS) += saa6752hs.o
>  obj-$(CONFIG_VIDEO_AD5820)  += ad5820.o
>  obj-$(CONFIG_VIDEO_AK7375)  += ak7375.o
>  obj-$(CONFIG_VIDEO_DW9714)  += dw9714.o
> +obj-$(CONFIG_VIDEO_DW9768)  += dw9768.o
>  obj-$(CONFIG_VIDEO_DW9807_VCM)  += dw9807-vcm.o
>  obj-$(CONFIG_VIDEO_ADV7170) += adv7170.o
>  obj-$(CONFIG_VIDEO_ADV7175) += adv7175.o
> diff --git a/drivers/media/i2c/dw9768.c b/drivers/media/i2c/dw9768.c
> new file mode 100644
> index 0000000..f5b5591
> --- /dev/null
> +++ b/drivers/media/i2c/dw9768.c
> @@ -0,0 +1,458 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2018 MediaTek Inc.
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/i2c.h>
> +#include <linux/module.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/pm_runtime.h>
> +#include <media/v4l2-ctrls.h>
> +#include <media/v4l2-device.h>
> +#include <media/v4l2-subdev.h>
> +
> +#define DW9768_VOLTAGE_ANALOG			2800000
> +#define DW9768_NAME				"dw9768"
> +#define DW9768_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 DW9768_FOCUS_STEPS			1
> +
> +#define DW9768_CTRL_DELAY_US			5000
> +
> +#define DW9768_REG_DAC_MSB			0x03
> +#define DW9768_REG_DAC_LSB			0x04
> +#define DW9768_REG_NULL				0xff
> +
> +#define DW9768_DAC_SHIFT			8
> +
> +#define DW9768_REG_VALUE_16BIT			2
> +
> +/* dw9768 device structure */
> +struct dw9768_device {
> +	struct v4l2_ctrl_handler ctrls;
> +	struct v4l2_subdev sd;
> +	struct regulator *analog_regulator;
> +	/*
> +	 * Serialize control access, get/set format, get selection
> +	 * and start streaming.
> +	 */
> +	struct mutex power_lock;
> +
> +	int power_count;
> +	bool standby;
> +};
> +
> +static inline struct dw9768_device *to_dw9768_vcm(struct v4l2_ctrl *ctrl)
> +{
> +	return container_of(ctrl->handler, struct dw9768_device, ctrls);
> +}
> +
> +static inline struct dw9768_device *sd_to_dw9768_vcm(struct v4l2_subdev *subdev)
> +{
> +	return container_of(subdev, struct dw9768_device, sd);
> +}
> +
> +static int dw9768_i2c_write(struct dw9768_device *dw9768_dev, u8 *data,
> +			    int size)
> +{
> +	struct i2c_client *client = v4l2_get_subdevdata(&dw9768_dev->sd);
> +	struct i2c_msg msg;
> +	u8 *w_buf = NULL;
> +	u8 retry_cnt = 3;
> +	int ret;
> +
> +	if (!client->adapter)
> +		return -ENODEV;
> +
> +	if (size != 1 && size != 2)
> +		return -EINVAL;
> +
> +	memset(&msg, 0, sizeof(struct i2c_msg));
> +
> +	w_buf = kzalloc(size, GFP_KERNEL);
> +	if (!w_buf)
> +		return -1;
return -ENOMEM;
> +
> +	memcpy(w_buf, data, size);
> +
> +	msg.addr  = client->addr;
> +	msg.flags = 0;
> +	msg.len   = size;
> +	msg.buf   = w_buf;
> +
> +	do {
> +		ret = i2c_transfer(client->adapter, &msg, 1);
> +		if (ret != 1)
> +			dev_err(&client->dev, "write fail, ret:%d, retry:%d\n",
> +				ret, retry_cnt);
> +		else
> +			break;
> +		retry_cnt--;
> +	} while (retry_cnt != 0);
> +
> +	if (retry_cnt == 0)	{
> +		dev_err(&client->dev, "i2c write fail(%d)\n", ret);
> +		return -EIO;
> +	}
> +
> +	kfree(w_buf);
> +
> +	return 0;
> +}
> +
> +static int dw9768_release(struct dw9768_device *dw9768_dev)
> +{
> +	unsigned char i;
> +	int ret;
> +
> +	char puSendCmdArray[4][2] = {
> +		{0x02, 0x00}, {DW9768_REG_NULL, DW9768_REG_NULL},
> +		{0x01, 0x00}, {DW9768_REG_NULL, DW9768_REG_NULL},
> +	};
> +
> +	for (i = 0; i < (sizeof(puSendCmdArray) / sizeof(char)) /
> +	     (sizeof(puSendCmdArray[0]) / sizeof(char)); i++) {> +		if (puSendCmdArray[i][0] != DW9768_REG_NULL) {
> +			ret = dw9768_i2c_write(dw9768_dev, puSendCmdArray[i],
> +					       DW9768_REG_VALUE_16BIT);
> +			if (ret < 0)
> +				return ret;
> +		} else {
> +			usleep_range(DW9768_CTRL_DELAY_US,
> +				     DW9768_CTRL_DELAY_US + 100);
> +		}
> +	}
Can we make this block more simple?  I think the loop is not necessary.
> +
> +	return 0;
> +}
> +
> +static int dw9768_init(struct dw9768_device *dw9768_dev)
> +{
> +	unsigned char i;
> +	int ret;
> +
> +	char puSendCmdArray[5][2] = {
> +		{0x02, 0x02}, {DW9768_REG_NULL, DW9768_REG_NULL},
> +		{0x06, 0x41}, {0x07, 0x39}, {DW9768_REG_NULL, DW9768_REG_NULL},
> +	};
> +
> +	for (i = 0; i < (sizeof(puSendCmdArray) / sizeof(char)) /
> +	     (sizeof(puSendCmdArray[0]) / sizeof(char)); i++) {
> +		if (puSendCmdArray[i][0] != DW9768_REG_NULL) {
> +			ret = dw9768_i2c_write(dw9768_dev, puSendCmdArray[i],
> +					       DW9768_REG_VALUE_16BIT);
> +			if (ret < 0)
> +				return ret;
> +		} else {
> +			usleep_range(DW9768_CTRL_DELAY_US,
> +				     DW9768_CTRL_DELAY_US + 100);
> +		}
> +	}
Ditto.
> +
> +	return 0;
> +}
> +
> +/*
> + * Power handling
> + */
> +static int dw9768_power_off(struct dw9768_device *dw9768_dev, bool standby)
> +{
> +	struct i2c_client *client = v4l2_get_subdevdata(&dw9768_dev->sd);
> +	int ret;
> +
> +	/*
> +	 * Go to standby first as real power off my be denied by the hardware
typo? "may be denied"
> +	 * (single power line control for both dw9768_dev and sensor).
> +	 */
> +	if (standby) {
> +		dw9768_dev->standby = true;
> +		ret = dw9768_release(dw9768_dev);
> +		if (ret)
> +			dev_err(&client->dev, "dw9768_release failed!\n");
> +	}
> +	ret = regulator_disable(dw9768_dev->analog_regulator);
> +	if (ret)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +static int dw9768_power_on(struct dw9768_device *dw9768_dev, bool restore)
> +{
> +	int ret;
> +
> +	ret = regulator_enable(dw9768_dev->analog_regulator);
> +	if (ret < 0)
> +		return ret;
> +
> +	if (restore) {
> +		/* Restore the hardware settings. */
> +		dw9768_dev->standby = false;
> +		ret = dw9768_init(dw9768_dev);
> +		if (ret < 0)
> +			goto fail;
> +	}
> +
> +	return 0;
> +
> +fail:
> +	dw9768_dev->standby = true;
> +	regulator_disable(dw9768_dev->analog_regulator);
> +
> +	return ret;
> +}
> +
> +/*
> + * 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 dw9768_update_hw(struct dw9768_device *dw9768_dev, u16 val)
> +{
> +	unsigned char i;
> +	int ret;
> +
> +	char puSendCmdArray[2][2] = {
> +		{DW9768_REG_DAC_MSB, (char)(val >> DW9768_DAC_SHIFT)},
> +		{DW9768_REG_DAC_LSB, (char)(val & 0xFF)},
> +	};
> +
> +	for (i = 0; i < (sizeof(puSendCmdArray) / sizeof(char)) /
> +	     (sizeof(puSendCmdArray[0]) / sizeof(char)); i++) {
> +		ret = dw9768_i2c_write(dw9768_dev, puSendCmdArray[i],
> +				       DW9768_REG_VALUE_16BIT);
> +		if (ret)
> +			return ret;
> +	}
ditto.
> +
> +	return 0;
> +}
> +
> +static int dw9768_set_ctrl(struct v4l2_ctrl *ctrl)
> +{
> +	struct dw9768_device *dw9768_dev = to_dw9768_vcm(ctrl);
> +
> +	if (ctrl->id == V4L2_CID_FOCUS_ABSOLUTE)
> +		return dw9768_update_hw(dw9768_dev, ctrl->val);
> +
> +	return 0;
> +}
> +
> +static const struct v4l2_ctrl_ops dw9768_vcm_ctrl_ops = {
> +	.s_ctrl = dw9768_set_ctrl,
> +};
> +
> +static int
> +dw9768_set_power(struct v4l2_subdev *subdev, int on)
> +{
> +	struct dw9768_device *dw9768_dev = sd_to_dw9768_vcm(subdev);
> +	int ret = 0;
> +
> +	mutex_lock(&dw9768_dev->power_lock);
> +
> +	/*
> +	 * If the power count is modified from 0 to != 0 or from != 0 to 0,
> +	 * update the power state.
> +	 */
> +	if (dw9768_dev->power_count == !on) {
> +		ret = on ? dw9768_power_on(dw9768_dev, true) :
> +			dw9768_power_off(dw9768_dev, true);
> +		if (ret < 0)
> +			goto done;
> +	}
> +
> +	/* Update the power count. */
> +	dw9768_dev->power_count += on ? 1 : -1;
> +	WARN_ON(dw9768_dev->power_count < 0);
> +
> +done:
> +	mutex_unlock(&dw9768_dev->power_lock);
> +	return ret;
> +}
> +
> +static int dw9768_open(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
> +{
> +	return dw9768_set_power(sd, 1);
> +}
> +
> +static int dw9768_close(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
> +{
> +	return dw9768_set_power(sd, 0);
> +}
I am a little confused about the pm control here.
Could we use the pm generic APIs to help do this?
> +
> +static const struct v4l2_subdev_internal_ops dw9768_int_ops = {
> +	.open = dw9768_open,
> +	.close = dw9768_close,
> +};
> +
> +static const struct v4l2_subdev_ops dw9768_ops = { };
> +
> +static void dw9768_subdev_cleanup(struct dw9768_device *dw9768_dev)
> +{
> +	v4l2_async_unregister_subdev(&dw9768_dev->sd);
> +	v4l2_ctrl_handler_free(&dw9768_dev->ctrls);
> +	media_entity_cleanup(&dw9768_dev->sd.entity);
> +}
> +
> +static int dw9768_init_controls(struct dw9768_device *dw9768_dev)
> +{
> +	struct v4l2_ctrl_handler *hdl = &dw9768_dev->ctrls;
> +	const struct v4l2_ctrl_ops *ops = &dw9768_vcm_ctrl_ops;
> +
> +	v4l2_ctrl_handler_init(hdl, 1);
> +
> +	v4l2_ctrl_new_std(hdl, ops, V4L2_CID_FOCUS_ABSOLUTE,
> +			  0, DW9768_MAX_FOCUS_POS, DW9768_FOCUS_STEPS, 0);
> +
> +	if (hdl->error) {
> +		dev_err(dw9768_dev->sd.dev, "%s fail error: 0x%x\n",
> +			__func__, hdl->error);
> +		return hdl->error;
> +	}
> +
> +	dw9768_dev->sd.ctrl_handler = hdl;
> +
> +	return 0;
> +}
> +
> +static int dw9768_probe(struct i2c_client *client)
> +{
> +	struct device *dev = &client->dev;
> +	struct dw9768_device *dw9768_dev;
> +	int rval;
> +
> +	dw9768_dev = devm_kzalloc(&client->dev, sizeof(*dw9768_dev),
> +				  GFP_KERNEL);
> +	if (!dw9768_dev)
> +		return -ENOMEM;
> +
> +	dw9768_dev->analog_regulator = devm_regulator_get(dev, "afvdd");
> +	if (IS_ERR(dw9768_dev->analog_regulator)) {
> +		dev_err(dev, "cannot get analog regulator\n");
> +		return PTR_ERR(dw9768_dev->analog_regulator);
> +	}
> +
> +	rval = regulator_set_voltage(dw9768_dev->analog_regulator,
> +				     DW9768_VOLTAGE_ANALOG,
> +				     DW9768_VOLTAGE_ANALOG);
> +	if (rval < 0) {
> +		dev_err(dev, "cannot set analog voltage\n");
> +		return rval;
> +	}
> +
> +	mutex_init(&dw9768_dev->power_lock);
> +
> +	v4l2_i2c_subdev_init(&dw9768_dev->sd, client, &dw9768_ops);
> +	dw9768_dev->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
> +	dw9768_dev->sd.internal_ops = &dw9768_int_ops;
> +
> +	rval = dw9768_init_controls(dw9768_dev);
> +	if (rval)
> +		goto err_cleanup;
> +
> +	rval = media_entity_pads_init(&dw9768_dev->sd.entity, 0, NULL);
> +	if (rval < 0)
> +		goto err_cleanup;
> +
> +	dw9768_dev->sd.entity.function = MEDIA_ENT_F_LENS;
> +
> +	rval = v4l2_async_register_subdev(&dw9768_dev->sd);
> +	if (rval < 0)
> +		goto err_cleanup;
> +
> +	pm_runtime_set_active(dev);
> +	pm_runtime_enable(dev);
> +	pm_runtime_idle(dev);
> +
> +	return 0;
> +
> +err_cleanup:
> +	mutex_destroy(&dw9768_dev->power_lock);
> +	dw9768_subdev_cleanup(dw9768_dev);
> +	dev_err(dev, "Probe failed: %d\n", rval);
> +	return rval;
> +}
> +
> +static int dw9768_remove(struct i2c_client *client)
> +{
> +	struct v4l2_subdev *sd = i2c_get_clientdata(client);
> +	struct dw9768_device *dw9768_dev = sd_to_dw9768_vcm(sd);
> +
> +	pm_runtime_disable(&client->dev);
> +	dw9768_subdev_cleanup(dw9768_dev);
> +
> +	return 0;
> +}
> +
> +/*
> + * This function sets the vcm position, so it consumes least current
> + * The lens position is gradually moved in units of DW9768_CTRL_STEPS,
> + * to make the movements smoothly.
> + */
> +static int __maybe_unused dw9768_vcm_suspend(struct device *dev)
> +{
> +	struct i2c_client *client = to_i2c_client(dev);
> +	struct v4l2_subdev *sd = i2c_get_clientdata(client);
> +	struct dw9768_device *dw9768_dev = sd_to_dw9768_vcm(sd);
> +
> +	if (!dw9768_dev->power_count)
> +		return 0;
> +
> +	return dw9768_power_off(dw9768_dev, false);
> +}
> +
> +/*
> + * 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 DW9768_CTRL_STEPS,
> + * to make the movements smoothly.
> + */
> +static int __maybe_unused dw9768_vcm_resume(struct device *dev)
> +{
> +	struct i2c_client *client = to_i2c_client(dev);
> +	struct v4l2_subdev *sd = i2c_get_clientdata(client);
> +	struct dw9768_device *dw9768_dev = sd_to_dw9768_vcm(sd);
> +
> +	if (!dw9768_dev->power_count)
> +		return 0;
> +
> +	return dw9768_power_on(dw9768_dev, true);
> +}
> +
> +static const struct i2c_device_id dw9768_id_table[] = {
> +	{ DW9768_NAME, 0 },
> +	{ { 0 } }
> +};
> +MODULE_DEVICE_TABLE(i2c, dw9768_id_table);
> +
> +static const struct of_device_id dw9768_of_table[] = {
> +	{ .compatible = "dongwoon,dw9768" },
> +	{ { 0 } }
> +};
> +MODULE_DEVICE_TABLE(of, dw9768_of_table);
> +
> +static const struct dev_pm_ops dw9768_pm_ops = {
> +	SET_SYSTEM_SLEEP_PM_OPS(dw9768_vcm_suspend, dw9768_vcm_resume)
> +	SET_RUNTIME_PM_OPS(dw9768_vcm_suspend, dw9768_vcm_resume, NULL)
> +};
> +
> +static struct i2c_driver dw9768_i2c_driver = {
> +	.driver = {
> +		.name = DW9768_NAME,
> +		.pm = &dw9768_pm_ops,
> +		.of_match_table = dw9768_of_table,
> +	},
> +	.probe_new  = dw9768_probe,
> +	.remove = dw9768_remove,
> +	.id_table = dw9768_id_table,
> +};
> +
> +module_i2c_driver(dw9768_i2c_driver);
> +
> +MODULE_AUTHOR("Dongchun Zhu <dongchun.zhu@mediatek.com>");
> +MODULE_DESCRIPTION("DW9768 VCM driver");
> +MODULE_LICENSE("GPL v2");
>
Tomasz Figa Aug. 23, 2019, 8:17 a.m. UTC | #2
Hi Dongchun,

On Mon, Jul 08, 2019 at 06:06:41PM +0800, dongchun.zhu@mediatek.com wrote:
> From: Dongchun Zhu <dongchun.zhu@mediatek.com>
> 
> This patch adds a V4L2 sub-device driver for DW9768 lens voice coil,
> and provides control to set the desired focus.
> 
> The DW9807 is a 10 bit DAC from Dongwoon, designed for linear
> control of voice coil motor.
> 
> Signed-off-by: Dongchun Zhu <dongchun.zhu@mediatek.com>
> ---
>  MAINTAINERS                |   1 +
>  drivers/media/i2c/Kconfig  |  10 +
>  drivers/media/i2c/Makefile |   1 +
>  drivers/media/i2c/dw9768.c | 458 +++++++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 470 insertions(+)
>  create mode 100644 drivers/media/i2c/dw9768.c
> 

Thanks for the patch! Please see my comments inline.

> diff --git a/MAINTAINERS b/MAINTAINERS
> index 8f6ac93..17152d7 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -4877,6 +4877,7 @@ M:	Dongchun Zhu <dongchun.zhu@mediatek.com>
>  L:	linux-media@vger.kernel.org
>  T:	git git://linuxtv.org/media_tree.git
>  S:	Maintained
> +F:	drivers/media/i2c/dw9768.c
>  F:	Documentation/devicetree/bindings/media/i2c/dongwoon,dw9768.txt
>  
>  DONGWOON DW9807 LENS VOICE COIL DRIVER
> diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
> index 7793358..8ff6c95 100644
> --- a/drivers/media/i2c/Kconfig
> +++ b/drivers/media/i2c/Kconfig
> @@ -1014,6 +1014,16 @@ config VIDEO_DW9714
>  	  capability. This is designed for linear control of
>  	  voice coil motors, controlled via I2C serial interface.
>  
> +config VIDEO_DW9768
> +	tristate "DW9768 lens voice coil support"
> +	depends on I2C && VIDEO_V4L2 && MEDIA_CONTROLLER
> +	depends on VIDEO_V4L2_SUBDEV_API
> +	help
> +	  This is a driver for the DW9768 camera lens voice coil.
> +	  DW9768 is a 10 bit DAC with 100mA output current sink
> +	  capability. This is designed for linear control of
> +	  voice coil motors, controlled via I2C serial interface.
> +
>  config VIDEO_DW9807_VCM
>  	tristate "DW9807 lens voice coil support"
>  	depends on I2C && VIDEO_V4L2 && MEDIA_CONTROLLER
> diff --git a/drivers/media/i2c/Makefile b/drivers/media/i2c/Makefile
> index d8ad9da..944fbf6 100644
> --- a/drivers/media/i2c/Makefile
> +++ b/drivers/media/i2c/Makefile
> @@ -24,6 +24,7 @@ obj-$(CONFIG_VIDEO_SAA6752HS) += saa6752hs.o
>  obj-$(CONFIG_VIDEO_AD5820)  += ad5820.o
>  obj-$(CONFIG_VIDEO_AK7375)  += ak7375.o
>  obj-$(CONFIG_VIDEO_DW9714)  += dw9714.o
> +obj-$(CONFIG_VIDEO_DW9768)  += dw9768.o
>  obj-$(CONFIG_VIDEO_DW9807_VCM)  += dw9807-vcm.o
>  obj-$(CONFIG_VIDEO_ADV7170) += adv7170.o
>  obj-$(CONFIG_VIDEO_ADV7175) += adv7175.o
> diff --git a/drivers/media/i2c/dw9768.c b/drivers/media/i2c/dw9768.c
> new file mode 100644
> index 0000000..f5b5591
> --- /dev/null
> +++ b/drivers/media/i2c/dw9768.c
> @@ -0,0 +1,458 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2018 MediaTek Inc.
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/i2c.h>
> +#include <linux/module.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/pm_runtime.h>
> +#include <media/v4l2-ctrls.h>
> +#include <media/v4l2-device.h>
> +#include <media/v4l2-subdev.h>
> +
> +#define DW9768_VOLTAGE_ANALOG			2800000

This is a platform detail and should be defined in the platform data, for
example DTS on platforms using DT.

> +#define DW9768_NAME				"dw9768"

The chip we seem to be using this driver for is called gt9769. Shouldn't we
call the driver the same?

> +#define DW9768_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 DW9768_FOCUS_STEPS			1
> +
> +#define DW9768_CTRL_DELAY_US			5000
> +
> +#define DW9768_REG_DAC_MSB			0x03
> +#define DW9768_REG_DAC_LSB			0x04
> +#define DW9768_REG_NULL				0xff
> +
> +#define DW9768_DAC_SHIFT			8
> +
> +#define DW9768_REG_VALUE_16BIT			2

This driver seems to always write 16-bit values. Can we simplify it to just
always assume so?

> +
> +/* dw9768 device structure */
> +struct dw9768_device {
> +	struct v4l2_ctrl_handler ctrls;
> +	struct v4l2_subdev sd;
> +	struct regulator *analog_regulator;
> +	/*
> +	 * Serialize control access, get/set format, get selection
> +	 * and start streaming.
> +	 */
> +	struct mutex power_lock;
> +
> +	int power_count;
> +	bool standby;
> +};
> +
> +static inline struct dw9768_device *to_dw9768_vcm(struct v4l2_ctrl *ctrl)
> +{
> +	return container_of(ctrl->handler, struct dw9768_device, ctrls);
> +}
> +
> +static inline struct dw9768_device *sd_to_dw9768_vcm(struct v4l2_subdev *subdev)
> +{
> +	return container_of(subdev, struct dw9768_device, sd);
> +}
> +
> +static int dw9768_i2c_write(struct dw9768_device *dw9768_dev, u8 *data,
> +			    int size)
> +{
> +	struct i2c_client *client = v4l2_get_subdevdata(&dw9768_dev->sd);
> +	struct i2c_msg msg;
> +	u8 *w_buf = NULL;
> +	u8 retry_cnt = 3;
> +	int ret;
> +
> +	if (!client->adapter)
> +		return -ENODEV;

This isn't possible.

> +
> +	if (size != 1 && size != 2)
> +		return -EINVAL;

All the calls always pass 2.

> +
> +	memset(&msg, 0, sizeof(struct i2c_msg));
> +
> +	w_buf = kzalloc(size, GFP_KERNEL);
> +	if (!w_buf)
> +		return -1;

The size is fixed to 2. Is it necessary to allocate the buffer dynamically?

> +
> +	memcpy(w_buf, data, size);
> +
> +	msg.addr  = client->addr;
> +	msg.flags = 0;
> +	msg.len   = size;
> +	msg.buf   = w_buf;

Actually, why don't we just use data directly?

> +
> +	do {
> +		ret = i2c_transfer(client->adapter, &msg, 1);
> +		if (ret != 1)
> +			dev_err(&client->dev, "write fail, ret:%d, retry:%d\n",
> +				ret, retry_cnt);
> +		else
> +			break;
> +		retry_cnt--;
> +	} while (retry_cnt != 0);
> +
> +	if (retry_cnt == 0)	{
> +		dev_err(&client->dev, "i2c write fail(%d)\n", ret);
> +		return -EIO;
> +	}

Why do we need to handle retries here? I don't see the hardware datasheet
refer to any need to do those. Are you seeing some issues with transfers?

> +
> +	kfree(w_buf);
> +
> +	return 0;
> +}
> +
> +static int dw9768_release(struct dw9768_device *dw9768_dev)
> +{
> +	unsigned char i;
> +	int ret;
> +
> +	char puSendCmdArray[4][2] = {

Please use the correct kernel coding style.

> +		{0x02, 0x00}, {DW9768_REG_NULL, DW9768_REG_NULL},
> +		{0x01, 0x00}, {DW9768_REG_NULL, DW9768_REG_NULL},

We only check the first element for this specific value, so we don't need
to initialize the second one.

Also, could we call it DW9768_CMD_DELAY instead?

Also, please define macros for the magic values used in the array.

> +	};
> +
> +	for (i = 0; i < (sizeof(puSendCmdArray) / sizeof(char)) /
> +	     (sizeof(puSendCmdArray[0]) / sizeof(char)); i++) {

Wouldn't ARRAY_SIZE() work here?

> +		if (puSendCmdArray[i][0] != DW9768_REG_NULL) {
> +			ret = dw9768_i2c_write(dw9768_dev, puSendCmdArray[i],
> +					       DW9768_REG_VALUE_16BIT);
> +			if (ret < 0)
> +				return ret;

Hmm, isn't this command array actually a pair of addreses and values?
Please define a struct for the entries.

Could we just use i2c_smbus_write_byte_data() instead of the custom
dw9768_i2c_write()?

> +		} else {
> +			usleep_range(DW9768_CTRL_DELAY_US,
> +				     DW9768_CTRL_DELAY_US + 100);
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +static int dw9768_init(struct dw9768_device *dw9768_dev)
> +{
> +	unsigned char i;
> +	int ret;
> +
> +	char puSendCmdArray[5][2] = {
> +		{0x02, 0x02}, {DW9768_REG_NULL, DW9768_REG_NULL},
> +		{0x06, 0x41}, {0x07, 0x39}, {DW9768_REG_NULL, DW9768_REG_NULL},
> +	};
> +
> +	for (i = 0; i < (sizeof(puSendCmdArray) / sizeof(char)) /
> +	     (sizeof(puSendCmdArray[0]) / sizeof(char)); i++) {
> +		if (puSendCmdArray[i][0] != DW9768_REG_NULL) {
> +			ret = dw9768_i2c_write(dw9768_dev, puSendCmdArray[i],
> +					       DW9768_REG_VALUE_16BIT);
> +			if (ret < 0)
> +				return ret;
> +		} else {
> +			usleep_range(DW9768_CTRL_DELAY_US,
> +				     DW9768_CTRL_DELAY_US + 100);
> +		}
> +	}

The code here is duplicated, just different command array is used. Could we
move the command array handling to a helper function? (+ all the comments
I mentioned above)

> +
> +	return 0;
> +}
> +
> +/*
> + * Power handling
> + */
> +static int dw9768_power_off(struct dw9768_device *dw9768_dev, bool standby)
> +{
> +	struct i2c_client *client = v4l2_get_subdevdata(&dw9768_dev->sd);
> +	int ret;
> +
> +	/*
> +	 * Go to standby first as real power off my be denied by the hardware
> +	 * (single power line control for both dw9768_dev and sensor).

What do you mean here? The regulator subsystem already properly handles
reference counting.

> +	 */
> +	if (standby) {
> +		dw9768_dev->standby = true;
> +		ret = dw9768_release(dw9768_dev);
> +		if (ret)
> +			dev_err(&client->dev, "dw9768_release failed!\n");

Shouldn't we always call this when we power off?

> +	}
> +	ret = regulator_disable(dw9768_dev->analog_regulator);
> +	if (ret)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +static int dw9768_power_on(struct dw9768_device *dw9768_dev, bool restore)
> +{
> +	int ret;
> +
> +	ret = regulator_enable(dw9768_dev->analog_regulator);
> +	if (ret < 0)
> +		return ret;
> +
> +	if (restore) {
> +		/* Restore the hardware settings. */
> +		dw9768_dev->standby = false;
> +		ret = dw9768_init(dw9768_dev);
> +		if (ret < 0)
> +			goto fail;

Shouldn't we always call this when we power on, without any condition?

> +	}
> +
> +	return 0;
> +
> +fail:
> +	dw9768_dev->standby = true;
> +	regulator_disable(dw9768_dev->analog_regulator);
> +
> +	return ret;
> +}

The two functions above should be called from the runtime PM suspend/resume
callbacks.

> +
> +/*
> + * 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 dw9768_update_hw(struct dw9768_device *dw9768_dev, u16 val)
> +{
> +	unsigned char i;
> +	int ret;
> +
> +	char puSendCmdArray[2][2] = {
> +		{DW9768_REG_DAC_MSB, (char)(val >> DW9768_DAC_SHIFT)},
> +		{DW9768_REG_DAC_LSB, (char)(val & 0xFF)},
> +	};
> +
> +	for (i = 0; i < (sizeof(puSendCmdArray) / sizeof(char)) /
> +	     (sizeof(puSendCmdArray[0]) / sizeof(char)); i++) {
> +		ret = dw9768_i2c_write(dw9768_dev, puSendCmdArray[i],
> +				       DW9768_REG_VALUE_16BIT);
> +		if (ret)
> +			return ret;
> +	}

Since the two registers are actually one after another, perhaps you could
use i2c_smbus_write_block_data() to batch them into one transfer?

> +
> +	return 0;
> +}
> +
> +static int dw9768_set_ctrl(struct v4l2_ctrl *ctrl)
> +{
> +	struct dw9768_device *dw9768_dev = to_dw9768_vcm(ctrl);
> +
> +	if (ctrl->id == V4L2_CID_FOCUS_ABSOLUTE)
> +		return dw9768_update_hw(dw9768_dev, ctrl->val);

I think we could just inline the contents of that function here, because
this function doesn't do anything else.

> +
> +	return 0;
> +}
> +
> +static const struct v4l2_ctrl_ops dw9768_vcm_ctrl_ops = {
> +	.s_ctrl = dw9768_set_ctrl,
> +};
> +
> +static int
> +dw9768_set_power(struct v4l2_subdev *subdev, int on)
> +{
> +	struct dw9768_device *dw9768_dev = sd_to_dw9768_vcm(subdev);
> +	int ret = 0;
> +
> +	mutex_lock(&dw9768_dev->power_lock);
> +
> +	/*
> +	 * If the power count is modified from 0 to != 0 or from != 0 to 0,
> +	 * update the power state.
> +	 */
> +	if (dw9768_dev->power_count == !on) {
> +		ret = on ? dw9768_power_on(dw9768_dev, true) :
> +			dw9768_power_off(dw9768_dev, true);
> +		if (ret < 0)
> +			goto done;
> +	}

If we use runtime PM, we get the reference count handling done for us by
the subsystem.

> +
> +	/* Update the power count. */
> +	dw9768_dev->power_count += on ? 1 : -1;
> +	WARN_ON(dw9768_dev->power_count < 0);
> +
> +done:
> +	mutex_unlock(&dw9768_dev->power_lock);
> +	return ret;
> +}
> +
> +static int dw9768_open(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
> +{
> +	return dw9768_set_power(sd, 1);

We could just call pm_runtime_get_sync() here.

> +}
> +
> +static int dw9768_close(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
> +{
> +	return dw9768_set_power(sd, 0);

And pm_runtime_put() here.

> +}
> +
> +static const struct v4l2_subdev_internal_ops dw9768_int_ops = {
> +	.open = dw9768_open,
> +	.close = dw9768_close,
> +};
> +
> +static const struct v4l2_subdev_ops dw9768_ops = { };
> +
> +static void dw9768_subdev_cleanup(struct dw9768_device *dw9768_dev)
> +{
> +	v4l2_async_unregister_subdev(&dw9768_dev->sd);
> +	v4l2_ctrl_handler_free(&dw9768_dev->ctrls);
> +	media_entity_cleanup(&dw9768_dev->sd.entity);
> +}
> +
> +static int dw9768_init_controls(struct dw9768_device *dw9768_dev)
> +{
> +	struct v4l2_ctrl_handler *hdl = &dw9768_dev->ctrls;
> +	const struct v4l2_ctrl_ops *ops = &dw9768_vcm_ctrl_ops;
> +
> +	v4l2_ctrl_handler_init(hdl, 1);
> +
> +	v4l2_ctrl_new_std(hdl, ops, V4L2_CID_FOCUS_ABSOLUTE,
> +			  0, DW9768_MAX_FOCUS_POS, DW9768_FOCUS_STEPS, 0);
> +
> +	if (hdl->error) {
> +		dev_err(dw9768_dev->sd.dev, "%s fail error: 0x%x\n",
> +			__func__, hdl->error);
> +		return hdl->error;
> +	}
> +
> +	dw9768_dev->sd.ctrl_handler = hdl;
> +
> +	return 0;
> +}
> +
> +static int dw9768_probe(struct i2c_client *client)
> +{
> +	struct device *dev = &client->dev;
> +	struct dw9768_device *dw9768_dev;

nit: Could we drop the _device and _dev suffixes to shorten the names?

> +	int rval;
> +
> +	dw9768_dev = devm_kzalloc(&client->dev, sizeof(*dw9768_dev),
> +				  GFP_KERNEL);
> +	if (!dw9768_dev)
> +		return -ENOMEM;
> +
> +	dw9768_dev->analog_regulator = devm_regulator_get(dev, "afvdd");

"avfdd" is the name on our camera module, not the chip. It should be "vdd".

> +	if (IS_ERR(dw9768_dev->analog_regulator)) {
> +		dev_err(dev, "cannot get analog regulator\n");
> +		return PTR_ERR(dw9768_dev->analog_regulator);
> +	}

We also need 1 more regulator here for the I2C interface. The datasheet
calls it "vin".

> +
> +	rval = regulator_set_voltage(dw9768_dev->analog_regulator,
> +				     DW9768_VOLTAGE_ANALOG,
> +				     DW9768_VOLTAGE_ANALOG);
> +	if (rval < 0) {
> +		dev_err(dev, "cannot set analog voltage\n");
> +		return rval;
> +	}

This should be set in the platform code. For example, on systems using DT
it can be done by setting the regulator min and max constraints in the DTS.

> +
> +	mutex_init(&dw9768_dev->power_lock);
> +
> +	v4l2_i2c_subdev_init(&dw9768_dev->sd, client, &dw9768_ops);
> +	dw9768_dev->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
> +	dw9768_dev->sd.internal_ops = &dw9768_int_ops;
> +
> +	rval = dw9768_init_controls(dw9768_dev);
> +	if (rval)
> +		goto err_cleanup;
> +
> +	rval = media_entity_pads_init(&dw9768_dev->sd.entity, 0, NULL);
> +	if (rval < 0)
> +		goto err_cleanup;
> +
> +	dw9768_dev->sd.entity.function = MEDIA_ENT_F_LENS;
> +
> +	rval = v4l2_async_register_subdev(&dw9768_dev->sd);
> +	if (rval < 0)
> +		goto err_cleanup;
> +
> +	pm_runtime_set_active(dev);

We shouldn't call this if we didn't fully power up the device ourselves and
I don't see the code above enabling the regulator. Given the privacy LED
concerns, we actually shouldn't attempt to power on in probe.

> +	pm_runtime_enable(dev);
> +	pm_runtime_idle(dev);

Ditto for idle, which is not needed if the device was not set active.

> +
> +	return 0;
> +
> +err_cleanup:
> +	mutex_destroy(&dw9768_dev->power_lock);
> +	dw9768_subdev_cleanup(dw9768_dev);
> +	dev_err(dev, "Probe failed: %d\n", rval);
> +	return rval;
> +}
> +
> +static int dw9768_remove(struct i2c_client *client)
> +{
> +	struct v4l2_subdev *sd = i2c_get_clientdata(client);
> +	struct dw9768_device *dw9768_dev = sd_to_dw9768_vcm(sd);
> +
> +	pm_runtime_disable(&client->dev);

Technically we need to check if (!pm_runtime_state_suspended()) and power
down manually and set_suspended if that was the case.

> +	dw9768_subdev_cleanup(dw9768_dev);
> +
> +	return 0;
> +}
> +
> +/*
> + * This function sets the vcm position, so it consumes least current
> + * The lens position is gradually moved in units of DW9768_CTRL_STEPS,
> + * to make the movements smoothly.
> + */
> +static int __maybe_unused dw9768_vcm_suspend(struct device *dev)
> +{
> +	struct i2c_client *client = to_i2c_client(dev);
> +	struct v4l2_subdev *sd = i2c_get_clientdata(client);
> +	struct dw9768_device *dw9768_dev = sd_to_dw9768_vcm(sd);
> +
> +	if (!dw9768_dev->power_count)
> +		return 0;
> +
> +	return dw9768_power_off(dw9768_dev, false);
> +}
> +
> +/*
> + * 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 DW9768_CTRL_STEPS,
> + * to make the movements smoothly.
> + */
> +static int __maybe_unused dw9768_vcm_resume(struct device *dev)
> +{
> +	struct i2c_client *client = to_i2c_client(dev);
> +	struct v4l2_subdev *sd = i2c_get_clientdata(client);
> +	struct dw9768_device *dw9768_dev = sd_to_dw9768_vcm(sd);
> +
> +	if (!dw9768_dev->power_count)
> +		return 0;
> +
> +	return dw9768_power_on(dw9768_dev, true);
> +}
> +
> +static const struct i2c_device_id dw9768_id_table[] = {
> +	{ DW9768_NAME, 0 },
> +	{ { 0 } }
> +};
> +MODULE_DEVICE_TABLE(i2c, dw9768_id_table);
> +
> +static const struct of_device_id dw9768_of_table[] = {
> +	{ .compatible = "dongwoon,dw9768" },
> +	{ { 0 } }
> +};
> +MODULE_DEVICE_TABLE(of, dw9768_of_table);
> +
> +static const struct dev_pm_ops dw9768_pm_ops = {
> +	SET_SYSTEM_SLEEP_PM_OPS(dw9768_vcm_suspend, dw9768_vcm_resume)
> +	SET_RUNTIME_PM_OPS(dw9768_vcm_suspend, dw9768_vcm_resume, NULL)

Okay, so we already provided the callbacks, but we never called
pm_runtime_get/put().

Also, I'm not sure if we can provide the same callbacks for runtime and
system PM ops, but I think we could use pm_runtime_force_suspend() and
pm_runtime_force_resume() as system ones to achieve the same.

Best regards,
Tomasz
Dongchun Zhu Sept. 2, 2019, 1:35 p.m. UTC | #3
Hi Bingbu,

On Wed, 2019-07-24 at 11:16 +0800, Bingbu Cao wrote:
> On 7/8/19 6:06 PM, dongchun.zhu@mediatek.com wrote:
> > From: Dongchun Zhu <dongchun.zhu@mediatek.com>
> >
> > This patch adds a V4L2 sub-device driver for DW9768 lens voice coil,
> > and provides control to set the desired focus.
> >
> > The DW9807 is a 10 bit DAC from Dongwoon, designed for linear control
> > of voice coil motor.
> >
> > Signed-off-by: Dongchun Zhu <dongchun.zhu@mediatek.com>
> > ---
> >  MAINTAINERS                |   1 +
> >  drivers/media/i2c/Kconfig  |  10 +
> >  drivers/media/i2c/Makefile |   1 +
> >  drivers/media/i2c/dw9768.c | 458
> > +++++++++++++++++++++++++++++++++++++++++++++
> >  4 files changed, 470 insertions(+)
> >  create mode 100644 drivers/media/i2c/dw9768.c
> >
> > diff --git a/MAINTAINERS b/MAINTAINERS index 8f6ac93..17152d7 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -4877,6 +4877,7 @@ M:Dongchun Zhu <dongchun.zhu@mediatek.com>
> >  L:linux-media@vger.kernel.org
> >  T:git git://linuxtv.org/media_tree.git
> >  S:Maintained
> > +F:drivers/media/i2c/dw9768.c
> >  F:Documentation/devicetree/bindings/media/i2c/dongwoon,dw9768.txt
> >
> >  DONGWOON DW9807 LENS VOICE COIL DRIVER diff --git
> > a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig index
> > 7793358..8ff6c95 100644
> > --- a/drivers/media/i2c/Kconfig
> > +++ b/drivers/media/i2c/Kconfig
> > @@ -1014,6 +1014,16 @@ config VIDEO_DW9714
> >    capability. This is designed for linear control of
> >    voice coil motors, controlled via I2C serial interface.
> >
> > +config VIDEO_DW9768
> > +tristate "DW9768 lens voice coil support"
> > +depends on I2C && VIDEO_V4L2 && MEDIA_CONTROLLER
> > +depends on VIDEO_V4L2_SUBDEV_API
> > +help
> > +  This is a driver for the DW9768 camera lens voice coil.
> > +  DW9768 is a 10 bit DAC with 100mA output current sink
> > +  capability. This is designed for linear control of
> > +  voice coil motors, controlled via I2C serial interface.
> > +
> >  config VIDEO_DW9807_VCM
> >  tristate "DW9807 lens voice coil support"
> >  depends on I2C && VIDEO_V4L2 && MEDIA_CONTROLLER diff --git
> > a/drivers/media/i2c/Makefile b/drivers/media/i2c/Makefile index
> > d8ad9da..944fbf6 100644
> > --- a/drivers/media/i2c/Makefile
> > +++ b/drivers/media/i2c/Makefile
> > @@ -24,6 +24,7 @@ obj-$(CONFIG_VIDEO_SAA6752HS) += saa6752hs.o
> >  obj-$(CONFIG_VIDEO_AD5820)  += ad5820.o
> >  obj-$(CONFIG_VIDEO_AK7375)  += ak7375.o
> >  obj-$(CONFIG_VIDEO_DW9714)  += dw9714.o
> > +obj-$(CONFIG_VIDEO_DW9768)  += dw9768.o
> >  obj-$(CONFIG_VIDEO_DW9807_VCM)  += dw9807-vcm.o
> >  obj-$(CONFIG_VIDEO_ADV7170) += adv7170.o
> >  obj-$(CONFIG_VIDEO_ADV7175) += adv7175.o diff --git
> > a/drivers/media/i2c/dw9768.c b/drivers/media/i2c/dw9768.c new file
> > mode 100644 index 0000000..f5b5591
> > --- /dev/null
> > +++ b/drivers/media/i2c/dw9768.c
> > @@ -0,0 +1,458 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Copyright (c) 2018 MediaTek Inc.
> > + */
> > +
> > +#include <linux/delay.h>
> > +#include <linux/i2c.h>
> > +#include <linux/module.h>
> > +#include <linux/regulator/consumer.h> #include <linux/pm_runtime.h>
> > +#include <media/v4l2-ctrls.h> #include <media/v4l2-device.h> #include
> > +<media/v4l2-subdev.h>
> > +
> > +#define DW9768_VOLTAGE_ANALOG2800000
> > +#define DW9768_NAME"dw9768"
> > +#define DW9768_MAX_FOCUS_POS1023
> > +/*
> > + * This sets the minimum granularity for the focus positions.
> > + * A value of 1 gives maximum accuracy for a desired focus position
> > +*/
> > +#define DW9768_FOCUS_STEPS1
> > +
> > +#define DW9768_CTRL_DELAY_US5000
> > +
> > +#define DW9768_REG_DAC_MSB0x03
> > +#define DW9768_REG_DAC_LSB0x04
> > +#define DW9768_REG_NULL0xff
> > +
> > +#define DW9768_DAC_SHIFT8
> > +
> > +#define DW9768_REG_VALUE_16BIT2
> > +
> > +/* dw9768 device structure */
> > +struct dw9768_device {
> > +struct v4l2_ctrl_handler ctrls;
> > +struct v4l2_subdev sd;
> > +struct regulator *analog_regulator;
> > +/*
> > + * Serialize control access, get/set format, get selection
> > + * and start streaming.
> > + */
> > +struct mutex power_lock;
> > +
> > +int power_count;
> > +bool standby;
> > +};
> > +
> > +static inline struct dw9768_device *to_dw9768_vcm(struct v4l2_ctrl
> > +*ctrl) {
> > +return container_of(ctrl->handler, struct dw9768_device, ctrls); }
> > +
> > +static inline struct dw9768_device *sd_to_dw9768_vcm(struct
> > +v4l2_subdev *subdev) {
> > +return container_of(subdev, struct dw9768_device, sd); }
> > +
> > +static int dw9768_i2c_write(struct dw9768_device *dw9768_dev, u8 *data,
> > +    int size)
> > +{
> > +struct i2c_client *client = v4l2_get_subdevdata(&dw9768_dev->sd);
> > +struct i2c_msg msg;
> > +u8 *w_buf = NULL;
> > +u8 retry_cnt = 3;
> > +int ret;
> > +
> > +if (!client->adapter)
> > +return -ENODEV;
> > +
> > +if (size != 1 && size != 2)
> > +return -EINVAL;
> > +
> > +memset(&msg, 0, sizeof(struct i2c_msg));
> > +
> > +w_buf = kzalloc(size, GFP_KERNEL);
> > +if (!w_buf)
> > +return -1;
> return -ENOMEM;

Fixed in next release.

> > +
> > +memcpy(w_buf, data, size);
> > +
> > +msg.addr  = client->addr;
> > +msg.flags = 0;
> > +msg.len   = size;
> > +msg.buf   = w_buf;
> > +
> > +do {
> > +ret = i2c_transfer(client->adapter, &msg, 1);
> > +if (ret != 1)
> > +dev_err(&client->dev, "write fail, ret:%d, retry:%d\n",
> > +ret, retry_cnt);
> > +else
> > +break;
> > +retry_cnt--;
> > +} while (retry_cnt != 0);
> > +
> > +if (retry_cnt == 0){
> > +dev_err(&client->dev, "i2c write fail(%d)\n", ret);
> > +return -EIO;
> > +}
> > +
> > +kfree(w_buf);
> > +
> > +return 0;
> > +}
> > +
> > +static int dw9768_release(struct dw9768_device *dw9768_dev) {
> > +unsigned char i;
> > +int ret;
> > +
> > +char puSendCmdArray[4][2] = {
> > +{0x02, 0x00}, {DW9768_REG_NULL, DW9768_REG_NULL},
> > +{0x01, 0x00}, {DW9768_REG_NULL, DW9768_REG_NULL},
> > +};
> > +
> > +for (i = 0; i < (sizeof(puSendCmdArray) / sizeof(char)) /
> > +     (sizeof(puSendCmdArray[0]) / sizeof(char)); i++) {> +if (puSendCmdArray[i][0] != DW9768_REG_NULL) {
> > +ret = dw9768_i2c_write(dw9768_dev, puSendCmdArray[i],
> > +       DW9768_REG_VALUE_16BIT);
> > +if (ret < 0)
> > +return ret;
> > +} else {
> > +usleep_range(DW9768_CTRL_DELAY_US,
> > +     DW9768_CTRL_DELAY_US + 100);
> > +}
> > +}
> Can we make this block more simple?  I think the loop is not necessary.

Fixed in next release.

> > +
> > +return 0;
> > +}
> > +
> > +static int dw9768_init(struct dw9768_device *dw9768_dev) {
> > +unsigned char i;
> > +int ret;
> > +
> > +char puSendCmdArray[5][2] = {
> > +{0x02, 0x02}, {DW9768_REG_NULL, DW9768_REG_NULL},
> > +{0x06, 0x41}, {0x07, 0x39}, {DW9768_REG_NULL, DW9768_REG_NULL},
> > +};
> > +
> > +for (i = 0; i < (sizeof(puSendCmdArray) / sizeof(char)) /
> > +     (sizeof(puSendCmdArray[0]) / sizeof(char)); i++) {
> > +if (puSendCmdArray[i][0] != DW9768_REG_NULL) {
> > +ret = dw9768_i2c_write(dw9768_dev, puSendCmdArray[i],
> > +       DW9768_REG_VALUE_16BIT);
> > +if (ret < 0)
> > +return ret;
> > +} else {
> > +usleep_range(DW9768_CTRL_DELAY_US,
> > +     DW9768_CTRL_DELAY_US + 100);
> > +}
> > +}
> Ditto.

Fixed in next release.

> > +
> > +return 0;
> > +}
> > +
> > +/*
> > + * Power handling
> > + */
> > +static int dw9768_power_off(struct dw9768_device *dw9768_dev, bool
> > +standby) {
> > +struct i2c_client *client = v4l2_get_subdevdata(&dw9768_dev->sd);
> > +int ret;
> > +
> > +/*
> > + * Go to standby first as real power off my be denied by the
> > +hardware
> typo? "may be denied"

Sorry for the typo. Fixed in next release.

> > + * (single power line control for both dw9768_dev and sensor).
> > + */
> > +if (standby) {
> > +dw9768_dev->standby = true;
> > +ret = dw9768_release(dw9768_dev);
> > +if (ret)
> > +dev_err(&client->dev, "dw9768_release failed!\n");
> > +}
> > +ret = regulator_disable(dw9768_dev->analog_regulator);
> > +if (ret)
> > +return ret;
> > +
> > +return 0;
> > +}
> > +
> > +static int dw9768_power_on(struct dw9768_device *dw9768_dev, bool
> > +restore) {
> > +int ret;
> > +
> > +ret = regulator_enable(dw9768_dev->analog_regulator);
> > +if (ret < 0)
> > +return ret;
> > +
> > +if (restore) {
> > +/* Restore the hardware settings. */
> > +dw9768_dev->standby = false;
> > +ret = dw9768_init(dw9768_dev);
> > +if (ret < 0)
> > +goto fail;
> > +}
> > +
> > +return 0;
> > +
> > +fail:
> > +dw9768_dev->standby = true;
> > +regulator_disable(dw9768_dev->analog_regulator);
> > +
> > +return ret;
> > +}
> > +
> > +/*
> > + * 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 dw9768_update_hw(struct dw9768_device *dw9768_dev, u16
> > +val) {
> > +unsigned char i;
> > +int ret;
> > +
> > +char puSendCmdArray[2][2] = {
> > +{DW9768_REG_DAC_MSB, (char)(val >> DW9768_DAC_SHIFT)},
> > +{DW9768_REG_DAC_LSB, (char)(val & 0xFF)},
> > +};
> > +
> > +for (i = 0; i < (sizeof(puSendCmdArray) / sizeof(char)) /
> > +     (sizeof(puSendCmdArray[0]) / sizeof(char)); i++) {
> > +ret = dw9768_i2c_write(dw9768_dev, puSendCmdArray[i],
> > +       DW9768_REG_VALUE_16BIT);
> > +if (ret)
> > +return ret;
> > +}
> ditto.

Fixed in next release.

> > +
> > +return 0;
> > +}
> > +
> > +static int dw9768_set_ctrl(struct v4l2_ctrl *ctrl) {
> > +struct dw9768_device *dw9768_dev = to_dw9768_vcm(ctrl);
> > +
> > +if (ctrl->id == V4L2_CID_FOCUS_ABSOLUTE)
> > +return dw9768_update_hw(dw9768_dev, ctrl->val);
> > +
> > +return 0;
> > +}
> > +
> > +static const struct v4l2_ctrl_ops dw9768_vcm_ctrl_ops = {
> > +.s_ctrl = dw9768_set_ctrl,
> > +};
> > +
> > +static int
> > +dw9768_set_power(struct v4l2_subdev *subdev, int on) {
> > +struct dw9768_device *dw9768_dev = sd_to_dw9768_vcm(subdev);
> > +int ret = 0;
> > +
> > +mutex_lock(&dw9768_dev->power_lock);
> > +
> > +/*
> > + * If the power count is modified from 0 to != 0 or from != 0 to 0,
> > + * update the power state.
> > + */
> > +if (dw9768_dev->power_count == !on) {
> > +ret = on ? dw9768_power_on(dw9768_dev, true) :
> > +dw9768_power_off(dw9768_dev, true);
> > +if (ret < 0)
> > +goto done;
> > +}
> > +
> > +/* Update the power count. */
> > +dw9768_dev->power_count += on ? 1 : -1;
> > +WARN_ON(dw9768_dev->power_count < 0);
> > +
> > +done:
> > +mutex_unlock(&dw9768_dev->power_lock);
> > +return ret;
> > +}
> > +
> > +static int dw9768_open(struct v4l2_subdev *sd, struct v4l2_subdev_fh
> > +*fh) {
> > +return dw9768_set_power(sd, 1);
> > +}
> > +
> > +static int dw9768_close(struct v4l2_subdev *sd, struct v4l2_subdev_fh
> > +*fh) {
> > +return dw9768_set_power(sd, 0);
> > +}
> I am a little confused about the pm control here.
> Could we use the pm generic APIs to help do this?

Fixed in next release.

> > +
> > +static const struct v4l2_subdev_internal_ops dw9768_int_ops = {
> > +.open = dw9768_open,
> > +.close = dw9768_close,
> > +};
> > +
> > +static const struct v4l2_subdev_ops dw9768_ops = { };
> > +
> > +static void dw9768_subdev_cleanup(struct dw9768_device *dw9768_dev) {
> > +v4l2_async_unregister_subdev(&dw9768_dev->sd);
> > +v4l2_ctrl_handler_free(&dw9768_dev->ctrls);
> > +media_entity_cleanup(&dw9768_dev->sd.entity);
> > +}
> > +
> > +static int dw9768_init_controls(struct dw9768_device *dw9768_dev) {
> > +struct v4l2_ctrl_handler *hdl = &dw9768_dev->ctrls;
> > +const struct v4l2_ctrl_ops *ops = &dw9768_vcm_ctrl_ops;
> > +
> > +v4l2_ctrl_handler_init(hdl, 1);
> > +
> > +v4l2_ctrl_new_std(hdl, ops, V4L2_CID_FOCUS_ABSOLUTE,
> > +  0, DW9768_MAX_FOCUS_POS, DW9768_FOCUS_STEPS, 0);
> > +
> > +if (hdl->error) {
> > +dev_err(dw9768_dev->sd.dev, "%s fail error: 0x%x\n",
> > +__func__, hdl->error);
> > +return hdl->error;
> > +}
> > +
> > +dw9768_dev->sd.ctrl_handler = hdl;
> > +
> > +return 0;
> > +}
> > +
> > +static int dw9768_probe(struct i2c_client *client) {
> > +struct device *dev = &client->dev;
> > +struct dw9768_device *dw9768_dev;
> > +int rval;
> > +
> > +dw9768_dev = devm_kzalloc(&client->dev, sizeof(*dw9768_dev),
> > +  GFP_KERNEL);
> > +if (!dw9768_dev)
> > +return -ENOMEM;
> > +
> > +dw9768_dev->analog_regulator = devm_regulator_get(dev, "afvdd");
> > +if (IS_ERR(dw9768_dev->analog_regulator)) {
> > +dev_err(dev, "cannot get analog regulator\n");
> > +return PTR_ERR(dw9768_dev->analog_regulator);
> > +}
> > +
> > +rval = regulator_set_voltage(dw9768_dev->analog_regulator,
> > +     DW9768_VOLTAGE_ANALOG,
> > +     DW9768_VOLTAGE_ANALOG);
> > +if (rval < 0) {
> > +dev_err(dev, "cannot set analog voltage\n");
> > +return rval;
> > +}
> > +
> > +mutex_init(&dw9768_dev->power_lock);
> > +
> > +v4l2_i2c_subdev_init(&dw9768_dev->sd, client, &dw9768_ops);
> > +dw9768_dev->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
> > +dw9768_dev->sd.internal_ops = &dw9768_int_ops;
> > +
> > +rval = dw9768_init_controls(dw9768_dev);
> > +if (rval)
> > +goto err_cleanup;
> > +
> > +rval = media_entity_pads_init(&dw9768_dev->sd.entity, 0, NULL);
> > +if (rval < 0)
> > +goto err_cleanup;
> > +
> > +dw9768_dev->sd.entity.function = MEDIA_ENT_F_LENS;
> > +
> > +rval = v4l2_async_register_subdev(&dw9768_dev->sd);
> > +if (rval < 0)
> > +goto err_cleanup;
> > +
> > +pm_runtime_set_active(dev);
> > +pm_runtime_enable(dev);
> > +pm_runtime_idle(dev);
> > +
> > +return 0;
> > +
> > +err_cleanup:
> > +mutex_destroy(&dw9768_dev->power_lock);
> > +dw9768_subdev_cleanup(dw9768_dev);
> > +dev_err(dev, "Probe failed: %d\n", rval);
> > +return rval;
> > +}
> > +
> > +static int dw9768_remove(struct i2c_client *client) {
> > +struct v4l2_subdev *sd = i2c_get_clientdata(client);
> > +struct dw9768_device *dw9768_dev = sd_to_dw9768_vcm(sd);
> > +
> > +pm_runtime_disable(&client->dev);
> > +dw9768_subdev_cleanup(dw9768_dev);
> > +
> > +return 0;
> > +}
> > +
> > +/*
> > + * This function sets the vcm position, so it consumes least current
> > + * The lens position is gradually moved in units of
> > +DW9768_CTRL_STEPS,
> > + * to make the movements smoothly.
> > + */
> > +static int __maybe_unused dw9768_vcm_suspend(struct device *dev) {
> > +struct i2c_client *client = to_i2c_client(dev);
> > +struct v4l2_subdev *sd = i2c_get_clientdata(client);
> > +struct dw9768_device *dw9768_dev = sd_to_dw9768_vcm(sd);
> > +
> > +if (!dw9768_dev->power_count)
> > +return 0;
> > +
> > +return dw9768_power_off(dw9768_dev, false); }
> > +
> > +/*
> > + * 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
> > +DW9768_CTRL_STEPS,
> > + * to make the movements smoothly.
> > + */
> > +static int __maybe_unused dw9768_vcm_resume(struct device *dev) {
> > +struct i2c_client *client = to_i2c_client(dev);
> > +struct v4l2_subdev *sd = i2c_get_clientdata(client);
> > +struct dw9768_device *dw9768_dev = sd_to_dw9768_vcm(sd);
> > +
> > +if (!dw9768_dev->power_count)
> > +return 0;
> > +
> > +return dw9768_power_on(dw9768_dev, true); }
> > +
> > +static const struct i2c_device_id dw9768_id_table[] = {
> > +{ DW9768_NAME, 0 },
> > +{ { 0 } }
> > +};
> > +MODULE_DEVICE_TABLE(i2c, dw9768_id_table);
> > +
> > +static const struct of_device_id dw9768_of_table[] = {
> > +{ .compatible = "dongwoon,dw9768" },
> > +{ { 0 } }
> > +};
> > +MODULE_DEVICE_TABLE(of, dw9768_of_table);
> > +
> > +static const struct dev_pm_ops dw9768_pm_ops = {
> > +SET_SYSTEM_SLEEP_PM_OPS(dw9768_vcm_suspend, dw9768_vcm_resume)
> > +SET_RUNTIME_PM_OPS(dw9768_vcm_suspend, dw9768_vcm_resume, NULL) };
> > +
> > +static struct i2c_driver dw9768_i2c_driver = {
> > +.driver = {
> > +.name = DW9768_NAME,
> > +.pm = &dw9768_pm_ops,
> > +.of_match_table = dw9768_of_table,
> > +},
> > +.probe_new  = dw9768_probe,
> > +.remove = dw9768_remove,
> > +.id_table = dw9768_id_table,
> > +};
> > +
> > +module_i2c_driver(dw9768_i2c_driver);
> > +
> > +MODULE_AUTHOR("Dongchun Zhu <dongchun.zhu@mediatek.com>");
> > +MODULE_DESCRIPTION("DW9768 VCM driver"); MODULE_LICENSE("GPL v2");
> >
> *********************MEDIATEK Confidential/Internal Use*********************
Dongchun Zhu Sept. 2, 2019, 3:01 p.m. UTC | #4
Hi Tomasz,

On Fri, 2019-08-23 at 17:17 +0900, Tomasz Figa wrote:
> Hi Dongchun,
> 
> On Mon, Jul 08, 2019 at 06:06:41PM +0800, dongchun.zhu@mediatek.com wrote:
> > From: Dongchun Zhu <dongchun.zhu@mediatek.com>
> > 
> > This patch adds a V4L2 sub-device driver for DW9768 lens voice coil,
> > and provides control to set the desired focus.
> > 
> > The DW9807 is a 10 bit DAC from Dongwoon, designed for linear
> > control of voice coil motor.
> > 
> > Signed-off-by: Dongchun Zhu <dongchun.zhu@mediatek.com>
> > ---
> >  MAINTAINERS                |   1 +
> >  drivers/media/i2c/Kconfig  |  10 +
> >  drivers/media/i2c/Makefile |   1 +
> >  drivers/media/i2c/dw9768.c | 458 +++++++++++++++++++++++++++++++++++++++++++++
> >  4 files changed, 470 insertions(+)
> >  create mode 100644 drivers/media/i2c/dw9768.c
> > 
> 
> Thanks for the patch! Please see my comments inline.
> 
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index 8f6ac93..17152d7 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -4877,6 +4877,7 @@ M:	Dongchun Zhu <dongchun.zhu@mediatek.com>
> >  L:	linux-media@vger.kernel.org
> >  T:	git git://linuxtv.org/media_tree.git
> >  S:	Maintained
> > +F:	drivers/media/i2c/dw9768.c
> >  F:	Documentation/devicetree/bindings/media/i2c/dongwoon,dw9768.txt
> >  
> >  DONGWOON DW9807 LENS VOICE COIL DRIVER
> > diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
> > index 7793358..8ff6c95 100644
> > --- a/drivers/media/i2c/Kconfig
> > +++ b/drivers/media/i2c/Kconfig
> > @@ -1014,6 +1014,16 @@ config VIDEO_DW9714
> >  	  capability. This is designed for linear control of
> >  	  voice coil motors, controlled via I2C serial interface.
> >  
> > +config VIDEO_DW9768
> > +	tristate "DW9768 lens voice coil support"
> > +	depends on I2C && VIDEO_V4L2 && MEDIA_CONTROLLER
> > +	depends on VIDEO_V4L2_SUBDEV_API
> > +	help
> > +	  This is a driver for the DW9768 camera lens voice coil.
> > +	  DW9768 is a 10 bit DAC with 100mA output current sink
> > +	  capability. This is designed for linear control of
> > +	  voice coil motors, controlled via I2C serial interface.
> > +
> >  config VIDEO_DW9807_VCM
> >  	tristate "DW9807 lens voice coil support"
> >  	depends on I2C && VIDEO_V4L2 && MEDIA_CONTROLLER
> > diff --git a/drivers/media/i2c/Makefile b/drivers/media/i2c/Makefile
> > index d8ad9da..944fbf6 100644
> > --- a/drivers/media/i2c/Makefile
> > +++ b/drivers/media/i2c/Makefile
> > @@ -24,6 +24,7 @@ obj-$(CONFIG_VIDEO_SAA6752HS) += saa6752hs.o
> >  obj-$(CONFIG_VIDEO_AD5820)  += ad5820.o
> >  obj-$(CONFIG_VIDEO_AK7375)  += ak7375.o
> >  obj-$(CONFIG_VIDEO_DW9714)  += dw9714.o
> > +obj-$(CONFIG_VIDEO_DW9768)  += dw9768.o
> >  obj-$(CONFIG_VIDEO_DW9807_VCM)  += dw9807-vcm.o
> >  obj-$(CONFIG_VIDEO_ADV7170) += adv7170.o
> >  obj-$(CONFIG_VIDEO_ADV7175) += adv7175.o
> > diff --git a/drivers/media/i2c/dw9768.c b/drivers/media/i2c/dw9768.c
> > new file mode 100644
> > index 0000000..f5b5591
> > --- /dev/null
> > +++ b/drivers/media/i2c/dw9768.c
> > @@ -0,0 +1,458 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Copyright (c) 2018 MediaTek Inc.
> > + */
> > +
> > +#include <linux/delay.h>
> > +#include <linux/i2c.h>
> > +#include <linux/module.h>
> > +#include <linux/regulator/consumer.h>
> > +#include <linux/pm_runtime.h>
> > +#include <media/v4l2-ctrls.h>
> > +#include <media/v4l2-device.h>
> > +#include <media/v4l2-subdev.h>
> > +
> > +#define DW9768_VOLTAGE_ANALOG			2800000
> 
> This is a platform detail and should be defined in the platform data, for
> example DTS on platforms using DT.
> 

Thanks for your reminder.
This would be fixed in next release.

> > +#define DW9768_NAME				"dw9768"
> 
> The chip we seem to be using this driver for is called gt9769. Shouldn't we
> call the driver the same?
> 

It is also called DW9768 from camera module specification, which was
initially confirmed with vendor.

> > +#define DW9768_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 DW9768_FOCUS_STEPS			1
> > +
> > +#define DW9768_CTRL_DELAY_US			5000
> > +
> > +#define DW9768_REG_DAC_MSB			0x03
> > +#define DW9768_REG_DAC_LSB			0x04
> > +#define DW9768_REG_NULL				0xff
> > +
> > +#define DW9768_DAC_SHIFT			8
> > +
> > +#define DW9768_REG_VALUE_16BIT			2
> 
> This driver seems to always write 16-bit values. Can we simplify it to just
> always assume so?
> 

Fixed in next release.

> > +
> > +/* dw9768 device structure */
> > +struct dw9768_device {
> > +	struct v4l2_ctrl_handler ctrls;
> > +	struct v4l2_subdev sd;
> > +	struct regulator *analog_regulator;
> > +	/*
> > +	 * Serialize control access, get/set format, get selection
> > +	 * and start streaming.
> > +	 */
> > +	struct mutex power_lock;
> > +
> > +	int power_count;
> > +	bool standby;
> > +};
> > +
> > +static inline struct dw9768_device *to_dw9768_vcm(struct v4l2_ctrl *ctrl)
> > +{
> > +	return container_of(ctrl->handler, struct dw9768_device, ctrls);
> > +}
> > +
> > +static inline struct dw9768_device *sd_to_dw9768_vcm(struct v4l2_subdev *subdev)
> > +{
> > +	return container_of(subdev, struct dw9768_device, sd);
> > +}
> > +
> > +static int dw9768_i2c_write(struct dw9768_device *dw9768_dev, u8 *data,
> > +			    int size)
> > +{
> > +	struct i2c_client *client = v4l2_get_subdevdata(&dw9768_dev->sd);
> > +	struct i2c_msg msg;
> > +	u8 *w_buf = NULL;
> > +	u8 retry_cnt = 3;
> > +	int ret;
> > +
> > +	if (!client->adapter)
> > +		return -ENODEV;
> 
> This isn't possible.
> 

Removed in next release.

> > +
> > +	if (size != 1 && size != 2)
> > +		return -EINVAL;
> 
> All the calls always pass 2.
> 

Fixed in next release.

> > +
> > +	memset(&msg, 0, sizeof(struct i2c_msg));
> > +
> > +	w_buf = kzalloc(size, GFP_KERNEL);
> > +	if (!w_buf)
> > +		return -1;
> 
> The size is fixed to 2. Is it necessary to allocate the buffer dynamically?
> 

Fixed in next release.

> > +
> > +	memcpy(w_buf, data, size);
> > +
> > +	msg.addr  = client->addr;
> > +	msg.flags = 0;
> > +	msg.len   = size;
> > +	msg.buf   = w_buf;
> 
> Actually, why don't we just use data directly?
> 

Fixed in next release.

> > +
> > +	do {
> > +		ret = i2c_transfer(client->adapter, &msg, 1);
> > +		if (ret != 1)
> > +			dev_err(&client->dev, "write fail, ret:%d, retry:%d\n",
> > +				ret, retry_cnt);
> > +		else
> > +			break;
> > +		retry_cnt--;
> > +	} while (retry_cnt != 0);
> > +
> > +	if (retry_cnt == 0)	{
> > +		dev_err(&client->dev, "i2c write fail(%d)\n", ret);
> > +		return -EIO;
> > +	}
> 
> Why do we need to handle retries here? I don't see the hardware datasheet
> refer to any need to do those. Are you seeing some issues with transfers?
> 

This is used to processing i2c transfer showing abnormality in some
cases.
Retries handler would be removed in next release.

> > +
> > +	kfree(w_buf);
> > +
> > +	return 0;
> > +}
> > +
> > +static int dw9768_release(struct dw9768_device *dw9768_dev)
> > +{
> > +	unsigned char i;
> > +	int ret;
> > +
> > +	char puSendCmdArray[4][2] = {
> 
> Please use the correct kernel coding style.
> 

Fixed in next release.

> > +		{0x02, 0x00}, {DW9768_REG_NULL, DW9768_REG_NULL},
> > +		{0x01, 0x00}, {DW9768_REG_NULL, DW9768_REG_NULL},
> 
> We only check the first element for this specific value, so we don't need
> to initialize the second one.
> 
> Also, could we call it DW9768_CMD_DELAY instead?
> 
> Also, please define macros for the magic values used in the array.
> 

This would be fixed in next release.

> > +	};
> > +
> > +	for (i = 0; i < (sizeof(puSendCmdArray) / sizeof(char)) /
> > +	     (sizeof(puSendCmdArray[0]) / sizeof(char)); i++) {
> 
> Wouldn't ARRAY_SIZE() work here?
> 

Fixed in next release.

> > +		if (puSendCmdArray[i][0] != DW9768_REG_NULL) {
> > +			ret = dw9768_i2c_write(dw9768_dev, puSendCmdArray[i],
> > +					       DW9768_REG_VALUE_16BIT);
> > +			if (ret < 0)
> > +				return ret;
> 
> Hmm, isn't this command array actually a pair of addreses and values?
> Please define a struct for the entries.
> 
> Could we just use i2c_smbus_write_byte_data() instead of the custom
> dw9768_i2c_write()?
> 

Thanks for great suggestion.
We would try i2c_smbus_write_byte_data API for write i2c register.

> > +		} else {
> > +			usleep_range(DW9768_CTRL_DELAY_US,
> > +				     DW9768_CTRL_DELAY_US + 100);
> > +		}
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +static int dw9768_init(struct dw9768_device *dw9768_dev)
> > +{
> > +	unsigned char i;
> > +	int ret;
> > +
> > +	char puSendCmdArray[5][2] = {
> > +		{0x02, 0x02}, {DW9768_REG_NULL, DW9768_REG_NULL},
> > +		{0x06, 0x41}, {0x07, 0x39}, {DW9768_REG_NULL, DW9768_REG_NULL},
> > +	};
> > +
> > +	for (i = 0; i < (sizeof(puSendCmdArray) / sizeof(char)) /
> > +	     (sizeof(puSendCmdArray[0]) / sizeof(char)); i++) {
> > +		if (puSendCmdArray[i][0] != DW9768_REG_NULL) {
> > +			ret = dw9768_i2c_write(dw9768_dev, puSendCmdArray[i],
> > +					       DW9768_REG_VALUE_16BIT);
> > +			if (ret < 0)
> > +				return ret;
> > +		} else {
> > +			usleep_range(DW9768_CTRL_DELAY_US,
> > +				     DW9768_CTRL_DELAY_US + 100);
> > +		}
> > +	}
> 
> The code here is duplicated, just different command array is used. Could we
> move the command array handling to a helper function? (+ all the comments
> I mentioned above)
> 

Fixed in next release.

> > +
> > +	return 0;
> > +}
> > +
> > +/*
> > + * Power handling
> > + */
> > +static int dw9768_power_off(struct dw9768_device *dw9768_dev, bool standby)
> > +{
> > +	struct i2c_client *client = v4l2_get_subdevdata(&dw9768_dev->sd);
> > +	int ret;
> > +
> > +	/*
> > +	 * Go to standby first as real power off my be denied by the hardware
> > +	 * (single power line control for both dw9768_dev and sensor).
> 
> What do you mean here? The regulator subsystem already properly handles
> reference counting.
> 

Understood.

> > +	 */
> > +	if (standby) {
> > +		dw9768_dev->standby = true;
> > +		ret = dw9768_release(dw9768_dev);
> > +		if (ret)
> > +			dev_err(&client->dev, "dw9768_release failed!\n");
> 
> Shouldn't we always call this when we power off?
> 
> > +	}
> > +	ret = regulator_disable(dw9768_dev->analog_regulator);
> > +	if (ret)
> > +		return ret;
> > +
> > +	return 0;
> > +}
> > +
> > +static int dw9768_power_on(struct dw9768_device *dw9768_dev, bool restore)
> > +{
> > +	int ret;
> > +
> > +	ret = regulator_enable(dw9768_dev->analog_regulator);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	if (restore) {
> > +		/* Restore the hardware settings. */
> > +		dw9768_dev->standby = false;
> > +		ret = dw9768_init(dw9768_dev);
> > +		if (ret < 0)
> > +			goto fail;
> 
> Shouldn't we always call this when we power on, without any condition?
> 
> > +	}
> > +
> > +	return 0;
> > +
> > +fail:
> > +	dw9768_dev->standby = true;
> > +	regulator_disable(dw9768_dev->analog_regulator);
> > +
> > +	return ret;
> > +}
> 
> The two functions above should be called from the runtime PM suspend/resume
> callbacks.
> 

Fixed in next release.

> > +
> > +/*
> > + * 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 dw9768_update_hw(struct dw9768_device *dw9768_dev, u16 val)
> > +{
> > +	unsigned char i;
> > +	int ret;
> > +
> > +	char puSendCmdArray[2][2] = {
> > +		{DW9768_REG_DAC_MSB, (char)(val >> DW9768_DAC_SHIFT)},
> > +		{DW9768_REG_DAC_LSB, (char)(val & 0xFF)},
> > +	};
> > +
> > +	for (i = 0; i < (sizeof(puSendCmdArray) / sizeof(char)) /
> > +	     (sizeof(puSendCmdArray[0]) / sizeof(char)); i++) {
> > +		ret = dw9768_i2c_write(dw9768_dev, puSendCmdArray[i],
> > +				       DW9768_REG_VALUE_16BIT);
> > +		if (ret)
> > +			return ret;
> > +	}
> 
> Since the two registers are actually one after another, perhaps you could
> use i2c_smbus_write_block_data() to batch them into one transfer?
> 

We would have a try.

> > +
> > +	return 0;
> > +}
> > +
> > +static int dw9768_set_ctrl(struct v4l2_ctrl *ctrl)
> > +{
> > +	struct dw9768_device *dw9768_dev = to_dw9768_vcm(ctrl);
> > +
> > +	if (ctrl->id == V4L2_CID_FOCUS_ABSOLUTE)
> > +		return dw9768_update_hw(dw9768_dev, ctrl->val);
> 
> I think we could just inline the contents of that function here, because
> this function doesn't do anything else.
> 

Fixed in next release.

> > +
> > +	return 0;
> > +}
> > +
> > +static const struct v4l2_ctrl_ops dw9768_vcm_ctrl_ops = {
> > +	.s_ctrl = dw9768_set_ctrl,
> > +};
> > +
> > +static int
> > +dw9768_set_power(struct v4l2_subdev *subdev, int on)
> > +{
> > +	struct dw9768_device *dw9768_dev = sd_to_dw9768_vcm(subdev);
> > +	int ret = 0;
> > +
> > +	mutex_lock(&dw9768_dev->power_lock);
> > +
> > +	/*
> > +	 * If the power count is modified from 0 to != 0 or from != 0 to 0,
> > +	 * update the power state.
> > +	 */
> > +	if (dw9768_dev->power_count == !on) {
> > +		ret = on ? dw9768_power_on(dw9768_dev, true) :
> > +			dw9768_power_off(dw9768_dev, true);
> > +		if (ret < 0)
> > +			goto done;
> > +	}
> 
> If we use runtime PM, we get the reference count handling done for us by
> the subsystem.
> 

Understood.

> > +
> > +	/* Update the power count. */
> > +	dw9768_dev->power_count += on ? 1 : -1;
> > +	WARN_ON(dw9768_dev->power_count < 0);
> > +
> > +done:
> > +	mutex_unlock(&dw9768_dev->power_lock);
> > +	return ret;
> > +}
> > +
> > +static int dw9768_open(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
> > +{
> > +	return dw9768_set_power(sd, 1);
> 
> We could just call pm_runtime_get_sync() here.
> 

Fixed in next release.

> > +}
> > +
> > +static int dw9768_close(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
> > +{
> > +	return dw9768_set_power(sd, 0);
> 
> And pm_runtime_put() here.
> 

Fixed in next release.

> > +}
> > +
> > +static const struct v4l2_subdev_internal_ops dw9768_int_ops = {
> > +	.open = dw9768_open,
> > +	.close = dw9768_close,
> > +};
> > +
> > +static const struct v4l2_subdev_ops dw9768_ops = { };
> > +
> > +static void dw9768_subdev_cleanup(struct dw9768_device *dw9768_dev)
> > +{
> > +	v4l2_async_unregister_subdev(&dw9768_dev->sd);
> > +	v4l2_ctrl_handler_free(&dw9768_dev->ctrls);
> > +	media_entity_cleanup(&dw9768_dev->sd.entity);
> > +}
> > +
> > +static int dw9768_init_controls(struct dw9768_device *dw9768_dev)
> > +{
> > +	struct v4l2_ctrl_handler *hdl = &dw9768_dev->ctrls;
> > +	const struct v4l2_ctrl_ops *ops = &dw9768_vcm_ctrl_ops;
> > +
> > +	v4l2_ctrl_handler_init(hdl, 1);
> > +
> > +	v4l2_ctrl_new_std(hdl, ops, V4L2_CID_FOCUS_ABSOLUTE,
> > +			  0, DW9768_MAX_FOCUS_POS, DW9768_FOCUS_STEPS, 0);
> > +
> > +	if (hdl->error) {
> > +		dev_err(dw9768_dev->sd.dev, "%s fail error: 0x%x\n",
> > +			__func__, hdl->error);
> > +		return hdl->error;
> > +	}
> > +
> > +	dw9768_dev->sd.ctrl_handler = hdl;
> > +
> > +	return 0;
> > +}
> > +
> > +static int dw9768_probe(struct i2c_client *client)
> > +{
> > +	struct device *dev = &client->dev;
> > +	struct dw9768_device *dw9768_dev;
> 
> nit: Could we drop the _device and _dev suffixes to shorten the names?
> 

Fixed in next release.

> > +	int rval;
> > +
> > +	dw9768_dev = devm_kzalloc(&client->dev, sizeof(*dw9768_dev),
> > +				  GFP_KERNEL);
> > +	if (!dw9768_dev)
> > +		return -ENOMEM;
> > +
> > +	dw9768_dev->analog_regulator = devm_regulator_get(dev, "afvdd");
> 
> "avfdd" is the name on our camera module, not the chip. It should be "vdd".
> 

Fixed in next release.

> > +	if (IS_ERR(dw9768_dev->analog_regulator)) {
> > +		dev_err(dev, "cannot get analog regulator\n");
> > +		return PTR_ERR(dw9768_dev->analog_regulator);
> > +	}
> 
> We also need 1 more regulator here for the I2C interface. The datasheet
> calls it "vin".
> 

Fixed in next release.

> > +
> > +	rval = regulator_set_voltage(dw9768_dev->analog_regulator,
> > +				     DW9768_VOLTAGE_ANALOG,
> > +				     DW9768_VOLTAGE_ANALOG);
> > +	if (rval < 0) {
> > +		dev_err(dev, "cannot set analog voltage\n");
> > +		return rval;
> > +	}
> 
> This should be set in the platform code. For example, on systems using DT
> it can be done by setting the regulator min and max constraints in the DTS.
> 

Fixed in next release.

> > +
> > +	mutex_init(&dw9768_dev->power_lock);
> > +
> > +	v4l2_i2c_subdev_init(&dw9768_dev->sd, client, &dw9768_ops);
> > +	dw9768_dev->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
> > +	dw9768_dev->sd.internal_ops = &dw9768_int_ops;
> > +
> > +	rval = dw9768_init_controls(dw9768_dev);
> > +	if (rval)
> > +		goto err_cleanup;
> > +
> > +	rval = media_entity_pads_init(&dw9768_dev->sd.entity, 0, NULL);
> > +	if (rval < 0)
> > +		goto err_cleanup;
> > +
> > +	dw9768_dev->sd.entity.function = MEDIA_ENT_F_LENS;
> > +
> > +	rval = v4l2_async_register_subdev(&dw9768_dev->sd);
> > +	if (rval < 0)
> > +		goto err_cleanup;
> > +
> > +	pm_runtime_set_active(dev);
> 
> We shouldn't call this if we didn't fully power up the device ourselves and
> I don't see the code above enabling the regulator. Given the privacy LED
> concerns, we actually shouldn't attempt to power on in probe.
> 

Understood.

> > +	pm_runtime_enable(dev);
> > +	pm_runtime_idle(dev);
> 
> Ditto for idle, which is not needed if the device was not set active.
> 

Fixed in next release.

> > +
> > +	return 0;
> > +
> > +err_cleanup:
> > +	mutex_destroy(&dw9768_dev->power_lock);
> > +	dw9768_subdev_cleanup(dw9768_dev);
> > +	dev_err(dev, "Probe failed: %d\n", rval);
> > +	return rval;
> > +}
> > +
> > +static int dw9768_remove(struct i2c_client *client)
> > +{
> > +	struct v4l2_subdev *sd = i2c_get_clientdata(client);
> > +	struct dw9768_device *dw9768_dev = sd_to_dw9768_vcm(sd);
> > +
> > +	pm_runtime_disable(&client->dev);
> 
> Technically we need to check if (!pm_runtime_state_suspended()) and power
> down manually and set_suspended if that was the case.
> 

Fixed in next release.

> > +	dw9768_subdev_cleanup(dw9768_dev);
> > +
> > +	return 0;
> > +}
> > +
> > +/*
> > + * This function sets the vcm position, so it consumes least current
> > + * The lens position is gradually moved in units of DW9768_CTRL_STEPS,
> > + * to make the movements smoothly.
> > + */
> > +static int __maybe_unused dw9768_vcm_suspend(struct device *dev)
> > +{
> > +	struct i2c_client *client = to_i2c_client(dev);
> > +	struct v4l2_subdev *sd = i2c_get_clientdata(client);
> > +	struct dw9768_device *dw9768_dev = sd_to_dw9768_vcm(sd);
> > +
> > +	if (!dw9768_dev->power_count)
> > +		return 0;
> > +
> > +	return dw9768_power_off(dw9768_dev, false);
> > +}
> > +
> > +/*
> > + * 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 DW9768_CTRL_STEPS,
> > + * to make the movements smoothly.
> > + */
> > +static int __maybe_unused dw9768_vcm_resume(struct device *dev)
> > +{
> > +	struct i2c_client *client = to_i2c_client(dev);
> > +	struct v4l2_subdev *sd = i2c_get_clientdata(client);
> > +	struct dw9768_device *dw9768_dev = sd_to_dw9768_vcm(sd);
> > +
> > +	if (!dw9768_dev->power_count)
> > +		return 0;
> > +
> > +	return dw9768_power_on(dw9768_dev, true);
> > +}
> > +
> > +static const struct i2c_device_id dw9768_id_table[] = {
> > +	{ DW9768_NAME, 0 },
> > +	{ { 0 } }
> > +};
> > +MODULE_DEVICE_TABLE(i2c, dw9768_id_table);
> > +
> > +static const struct of_device_id dw9768_of_table[] = {
> > +	{ .compatible = "dongwoon,dw9768" },
> > +	{ { 0 } }
> > +};
> > +MODULE_DEVICE_TABLE(of, dw9768_of_table);
> > +
> > +static const struct dev_pm_ops dw9768_pm_ops = {
> > +	SET_SYSTEM_SLEEP_PM_OPS(dw9768_vcm_suspend, dw9768_vcm_resume)
> > +	SET_RUNTIME_PM_OPS(dw9768_vcm_suspend, dw9768_vcm_resume, NULL)
> 
> Okay, so we already provided the callbacks, but we never called
> pm_runtime_get/put().
> 
> Also, I'm not sure if we can provide the same callbacks for runtime and
> system PM ops, but I think we could use pm_runtime_force_suspend() and
> pm_runtime_force_resume() as system ones to achieve the same.
> 

SET_SYSTEM_SLEEP_PM_OPS would use pm_runtime_force_suspend/resume in
next release.

> Best regards,
> Tomasz
Tomasz Figa Sept. 3, 2019, 3:50 a.m. UTC | #5
Hi Dongchun,

On Tue, Sep 3, 2019 at 12:02 AM Dongchun Zhu <dongchun.zhu@mediatek.com> wrote:
>
> Hi Tomasz,
>
> On Fri, 2019-08-23 at 17:17 +0900, Tomasz Figa wrote:
> > Hi Dongchun,
> >
> > On Mon, Jul 08, 2019 at 06:06:41PM +0800, dongchun.zhu@mediatek.com wrote:
> > > From: Dongchun Zhu <dongchun.zhu@mediatek.com>
> > >
> > > This patch adds a V4L2 sub-device driver for DW9768 lens voice coil,
> > > and provides control to set the desired focus.
> > >
> > > The DW9807 is a 10 bit DAC from Dongwoon, designed for linear
> > > control of voice coil motor.
> > >
> > > Signed-off-by: Dongchun Zhu <dongchun.zhu@mediatek.com>
> > > ---
> > >  MAINTAINERS                |   1 +
> > >  drivers/media/i2c/Kconfig  |  10 +
> > >  drivers/media/i2c/Makefile |   1 +
> > >  drivers/media/i2c/dw9768.c | 458 +++++++++++++++++++++++++++++++++++++++++++++
> > >  4 files changed, 470 insertions(+)
> > >  create mode 100644 drivers/media/i2c/dw9768.c
> > >
> >
> > Thanks for the patch! Please see my comments inline.
> >
> > > diff --git a/MAINTAINERS b/MAINTAINERS
> > > index 8f6ac93..17152d7 100644
> > > --- a/MAINTAINERS
> > > +++ b/MAINTAINERS
> > > @@ -4877,6 +4877,7 @@ M:    Dongchun Zhu <dongchun.zhu@mediatek.com>
> > >  L: linux-media@vger.kernel.org
> > >  T: git git://linuxtv.org/media_tree.git
> > >  S: Maintained
> > > +F: drivers/media/i2c/dw9768.c
> > >  F: Documentation/devicetree/bindings/media/i2c/dongwoon,dw9768.txt
> > >
> > >  DONGWOON DW9807 LENS VOICE COIL DRIVER
> > > diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
> > > index 7793358..8ff6c95 100644
> > > --- a/drivers/media/i2c/Kconfig
> > > +++ b/drivers/media/i2c/Kconfig
> > > @@ -1014,6 +1014,16 @@ config VIDEO_DW9714
> > >       capability. This is designed for linear control of
> > >       voice coil motors, controlled via I2C serial interface.
> > >
> > > +config VIDEO_DW9768
> > > +   tristate "DW9768 lens voice coil support"
> > > +   depends on I2C && VIDEO_V4L2 && MEDIA_CONTROLLER
> > > +   depends on VIDEO_V4L2_SUBDEV_API
> > > +   help
> > > +     This is a driver for the DW9768 camera lens voice coil.
> > > +     DW9768 is a 10 bit DAC with 100mA output current sink
> > > +     capability. This is designed for linear control of
> > > +     voice coil motors, controlled via I2C serial interface.
> > > +
> > >  config VIDEO_DW9807_VCM
> > >     tristate "DW9807 lens voice coil support"
> > >     depends on I2C && VIDEO_V4L2 && MEDIA_CONTROLLER
> > > diff --git a/drivers/media/i2c/Makefile b/drivers/media/i2c/Makefile
> > > index d8ad9da..944fbf6 100644
> > > --- a/drivers/media/i2c/Makefile
> > > +++ b/drivers/media/i2c/Makefile
> > > @@ -24,6 +24,7 @@ obj-$(CONFIG_VIDEO_SAA6752HS) += saa6752hs.o
> > >  obj-$(CONFIG_VIDEO_AD5820)  += ad5820.o
> > >  obj-$(CONFIG_VIDEO_AK7375)  += ak7375.o
> > >  obj-$(CONFIG_VIDEO_DW9714)  += dw9714.o
> > > +obj-$(CONFIG_VIDEO_DW9768)  += dw9768.o
> > >  obj-$(CONFIG_VIDEO_DW9807_VCM)  += dw9807-vcm.o
> > >  obj-$(CONFIG_VIDEO_ADV7170) += adv7170.o
> > >  obj-$(CONFIG_VIDEO_ADV7175) += adv7175.o
> > > diff --git a/drivers/media/i2c/dw9768.c b/drivers/media/i2c/dw9768.c
> > > new file mode 100644
> > > index 0000000..f5b5591
> > > --- /dev/null
> > > +++ b/drivers/media/i2c/dw9768.c
> > > @@ -0,0 +1,458 @@
> > > +// SPDX-License-Identifier: GPL-2.0
> > > +/*
> > > + * Copyright (c) 2018 MediaTek Inc.
> > > + */
> > > +
> > > +#include <linux/delay.h>
> > > +#include <linux/i2c.h>
> > > +#include <linux/module.h>
> > > +#include <linux/regulator/consumer.h>
> > > +#include <linux/pm_runtime.h>
> > > +#include <media/v4l2-ctrls.h>
> > > +#include <media/v4l2-device.h>
> > > +#include <media/v4l2-subdev.h>
> > > +
> > > +#define DW9768_VOLTAGE_ANALOG                      2800000
> >
> > This is a platform detail and should be defined in the platform data, for
> > example DTS on platforms using DT.
> >
>
> Thanks for your reminder.
> This would be fixed in next release.
>
> > > +#define DW9768_NAME                                "dw9768"
> >
> > The chip we seem to be using this driver for is called gt9769. Shouldn't we
> > call the driver the same?
> >
>
> It is also called DW9768 from camera module specification, which was
> initially confirmed with vendor.
>

Okay, thanks for clarifying.

Best regards,
Tomasz
Andy Shevchenko Sept. 4, 2019, 2:33 p.m. UTC | #6
On Mon, Jul 8, 2019 at 5:13 PM <dongchun.zhu@mediatek.com> wrote:
>
> From: Dongchun Zhu <dongchun.zhu@mediatek.com>
>
> This patch adds a V4L2 sub-device driver for DW9768 lens voice coil,
> and provides control to set the desired focus.
>
> The DW9807 is a 10 bit DAC from Dongwoon, designed for linear
> control of voice coil motor.

> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2018 MediaTek Inc.
> + */

2019?

> +       if (!client->adapter)
> +               return -ENODEV;

Is it ever possible?

> +       w_buf = kzalloc(size, GFP_KERNEL);
> +       if (!w_buf)
> +               return -1;

Error code?

> +       do {
> +               ret = i2c_transfer(client->adapter, &msg, 1);

> +               if (ret != 1)
> +                       dev_err(&client->dev, "write fail, ret:%d, retry:%d\n",
> +                               ret, retry_cnt);

This is noise. And better to use positive condition.

> +               else
> +                       break;

> +               retry_cnt--;
> +       } while (retry_cnt != 0);
> +

} while (--retry_cnt);

> +       if (retry_cnt == 0)     {
> +               dev_err(&client->dev, "i2c write fail(%d)\n", ret);
> +               return -EIO;
> +       }

> +
> +       kfree(w_buf);
> +
> +       return 0;
> +}

> +static int dw9768_power_off(struct dw9768_device *dw9768_dev, bool standby)
> +{
> +       struct i2c_client *client = v4l2_get_subdevdata(&dw9768_dev->sd);
> +       int ret;
> +
> +       /*
> +        * Go to standby first as real power off my be denied by the hardware
> +        * (single power line control for both dw9768_dev and sensor).
> +        */
> +       if (standby) {
> +               dw9768_dev->standby = true;
> +               ret = dw9768_release(dw9768_dev);

> +               if (ret)

> +                       dev_err(&client->dev, "dw9768_release failed!\n");

Is it fatal or not?

> +       }

> +       ret = regulator_disable(dw9768_dev->analog_regulator);
> +       if (ret)
> +               return ret;
> +
> +       return 0;

return regulator_disable(...);

> +}

> +               dev_err(dw9768_dev->sd.dev, "%s fail error: 0x%x\n",
> +                       __func__, hdl->error);

Non-informative message.

> +static int dw9768_probe(struct i2c_client *client)
> +{
> +       struct device *dev = &client->dev;
> +       struct dw9768_device *dw9768_dev;
> +       int rval;
> +
> +       dw9768_dev = devm_kzalloc(&client->dev, sizeof(*dw9768_dev),
> +                                 GFP_KERNEL);
> +       if (!dw9768_dev)
> +               return -ENOMEM;
> +
> +       dw9768_dev->analog_regulator = devm_regulator_get(dev, "afvdd");
> +       if (IS_ERR(dw9768_dev->analog_regulator)) {

> +               dev_err(dev, "cannot get analog regulator\n");

Would be noise in case of deferred probe.

> +               return PTR_ERR(dw9768_dev->analog_regulator);
> +       }

> +err_cleanup:
> +       mutex_destroy(&dw9768_dev->power_lock);
> +       dw9768_subdev_cleanup(dw9768_dev);

> +       dev_err(dev, "Probe failed: %d\n", rval);

Noise. Device core has this already.

> +       return rval;
> +}

> +static const struct i2c_device_id dw9768_id_table[] = {
> +       { DW9768_NAME, 0 },
> +       { { 0 } }

{} is enough.

> +};
> +MODULE_DEVICE_TABLE(i2c, dw9768_id_table);
> +
> +static const struct of_device_id dw9768_of_table[] = {
> +       { .compatible = "dongwoon,dw9768" },

> +       { { 0 } }

Ditto.

> +};

Patch
diff mbox series

diff --git a/MAINTAINERS b/MAINTAINERS
index 8f6ac93..17152d7 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -4877,6 +4877,7 @@  M:	Dongchun Zhu <dongchun.zhu@mediatek.com>
 L:	linux-media@vger.kernel.org
 T:	git git://linuxtv.org/media_tree.git
 S:	Maintained
+F:	drivers/media/i2c/dw9768.c
 F:	Documentation/devicetree/bindings/media/i2c/dongwoon,dw9768.txt
 
 DONGWOON DW9807 LENS VOICE COIL DRIVER
diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
index 7793358..8ff6c95 100644
--- a/drivers/media/i2c/Kconfig
+++ b/drivers/media/i2c/Kconfig
@@ -1014,6 +1014,16 @@  config VIDEO_DW9714
 	  capability. This is designed for linear control of
 	  voice coil motors, controlled via I2C serial interface.
 
+config VIDEO_DW9768
+	tristate "DW9768 lens voice coil support"
+	depends on I2C && VIDEO_V4L2 && MEDIA_CONTROLLER
+	depends on VIDEO_V4L2_SUBDEV_API
+	help
+	  This is a driver for the DW9768 camera lens voice coil.
+	  DW9768 is a 10 bit DAC with 100mA output current sink
+	  capability. This is designed for linear control of
+	  voice coil motors, controlled via I2C serial interface.
+
 config VIDEO_DW9807_VCM
 	tristate "DW9807 lens voice coil support"
 	depends on I2C && VIDEO_V4L2 && MEDIA_CONTROLLER
diff --git a/drivers/media/i2c/Makefile b/drivers/media/i2c/Makefile
index d8ad9da..944fbf6 100644
--- a/drivers/media/i2c/Makefile
+++ b/drivers/media/i2c/Makefile
@@ -24,6 +24,7 @@  obj-$(CONFIG_VIDEO_SAA6752HS) += saa6752hs.o
 obj-$(CONFIG_VIDEO_AD5820)  += ad5820.o
 obj-$(CONFIG_VIDEO_AK7375)  += ak7375.o
 obj-$(CONFIG_VIDEO_DW9714)  += dw9714.o
+obj-$(CONFIG_VIDEO_DW9768)  += dw9768.o
 obj-$(CONFIG_VIDEO_DW9807_VCM)  += dw9807-vcm.o
 obj-$(CONFIG_VIDEO_ADV7170) += adv7170.o
 obj-$(CONFIG_VIDEO_ADV7175) += adv7175.o
diff --git a/drivers/media/i2c/dw9768.c b/drivers/media/i2c/dw9768.c
new file mode 100644
index 0000000..f5b5591
--- /dev/null
+++ b/drivers/media/i2c/dw9768.c
@@ -0,0 +1,458 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2018 MediaTek Inc.
+ */
+
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/regulator/consumer.h>
+#include <linux/pm_runtime.h>
+#include <media/v4l2-ctrls.h>
+#include <media/v4l2-device.h>
+#include <media/v4l2-subdev.h>
+
+#define DW9768_VOLTAGE_ANALOG			2800000
+#define DW9768_NAME				"dw9768"
+#define DW9768_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 DW9768_FOCUS_STEPS			1
+
+#define DW9768_CTRL_DELAY_US			5000
+
+#define DW9768_REG_DAC_MSB			0x03
+#define DW9768_REG_DAC_LSB			0x04
+#define DW9768_REG_NULL				0xff
+
+#define DW9768_DAC_SHIFT			8
+
+#define DW9768_REG_VALUE_16BIT			2
+
+/* dw9768 device structure */
+struct dw9768_device {
+	struct v4l2_ctrl_handler ctrls;
+	struct v4l2_subdev sd;
+	struct regulator *analog_regulator;
+	/*
+	 * Serialize control access, get/set format, get selection
+	 * and start streaming.
+	 */
+	struct mutex power_lock;
+
+	int power_count;
+	bool standby;
+};
+
+static inline struct dw9768_device *to_dw9768_vcm(struct v4l2_ctrl *ctrl)
+{
+	return container_of(ctrl->handler, struct dw9768_device, ctrls);
+}
+
+static inline struct dw9768_device *sd_to_dw9768_vcm(struct v4l2_subdev *subdev)
+{
+	return container_of(subdev, struct dw9768_device, sd);
+}
+
+static int dw9768_i2c_write(struct dw9768_device *dw9768_dev, u8 *data,
+			    int size)
+{
+	struct i2c_client *client = v4l2_get_subdevdata(&dw9768_dev->sd);
+	struct i2c_msg msg;
+	u8 *w_buf = NULL;
+	u8 retry_cnt = 3;
+	int ret;
+
+	if (!client->adapter)
+		return -ENODEV;
+
+	if (size != 1 && size != 2)
+		return -EINVAL;
+
+	memset(&msg, 0, sizeof(struct i2c_msg));
+
+	w_buf = kzalloc(size, GFP_KERNEL);
+	if (!w_buf)
+		return -1;
+
+	memcpy(w_buf, data, size);
+
+	msg.addr  = client->addr;
+	msg.flags = 0;
+	msg.len   = size;
+	msg.buf   = w_buf;
+
+	do {
+		ret = i2c_transfer(client->adapter, &msg, 1);
+		if (ret != 1)
+			dev_err(&client->dev, "write fail, ret:%d, retry:%d\n",
+				ret, retry_cnt);
+		else
+			break;
+		retry_cnt--;
+	} while (retry_cnt != 0);
+
+	if (retry_cnt == 0)	{
+		dev_err(&client->dev, "i2c write fail(%d)\n", ret);
+		return -EIO;
+	}
+
+	kfree(w_buf);
+
+	return 0;
+}
+
+static int dw9768_release(struct dw9768_device *dw9768_dev)
+{
+	unsigned char i;
+	int ret;
+
+	char puSendCmdArray[4][2] = {
+		{0x02, 0x00}, {DW9768_REG_NULL, DW9768_REG_NULL},
+		{0x01, 0x00}, {DW9768_REG_NULL, DW9768_REG_NULL},
+	};
+
+	for (i = 0; i < (sizeof(puSendCmdArray) / sizeof(char)) /
+	     (sizeof(puSendCmdArray[0]) / sizeof(char)); i++) {
+		if (puSendCmdArray[i][0] != DW9768_REG_NULL) {
+			ret = dw9768_i2c_write(dw9768_dev, puSendCmdArray[i],
+					       DW9768_REG_VALUE_16BIT);
+			if (ret < 0)
+				return ret;
+		} else {
+			usleep_range(DW9768_CTRL_DELAY_US,
+				     DW9768_CTRL_DELAY_US + 100);
+		}
+	}
+
+	return 0;
+}
+
+static int dw9768_init(struct dw9768_device *dw9768_dev)
+{
+	unsigned char i;
+	int ret;
+
+	char puSendCmdArray[5][2] = {
+		{0x02, 0x02}, {DW9768_REG_NULL, DW9768_REG_NULL},
+		{0x06, 0x41}, {0x07, 0x39}, {DW9768_REG_NULL, DW9768_REG_NULL},
+	};
+
+	for (i = 0; i < (sizeof(puSendCmdArray) / sizeof(char)) /
+	     (sizeof(puSendCmdArray[0]) / sizeof(char)); i++) {
+		if (puSendCmdArray[i][0] != DW9768_REG_NULL) {
+			ret = dw9768_i2c_write(dw9768_dev, puSendCmdArray[i],
+					       DW9768_REG_VALUE_16BIT);
+			if (ret < 0)
+				return ret;
+		} else {
+			usleep_range(DW9768_CTRL_DELAY_US,
+				     DW9768_CTRL_DELAY_US + 100);
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * Power handling
+ */
+static int dw9768_power_off(struct dw9768_device *dw9768_dev, bool standby)
+{
+	struct i2c_client *client = v4l2_get_subdevdata(&dw9768_dev->sd);
+	int ret;
+
+	/*
+	 * Go to standby first as real power off my be denied by the hardware
+	 * (single power line control for both dw9768_dev and sensor).
+	 */
+	if (standby) {
+		dw9768_dev->standby = true;
+		ret = dw9768_release(dw9768_dev);
+		if (ret)
+			dev_err(&client->dev, "dw9768_release failed!\n");
+	}
+	ret = regulator_disable(dw9768_dev->analog_regulator);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int dw9768_power_on(struct dw9768_device *dw9768_dev, bool restore)
+{
+	int ret;
+
+	ret = regulator_enable(dw9768_dev->analog_regulator);
+	if (ret < 0)
+		return ret;
+
+	if (restore) {
+		/* Restore the hardware settings. */
+		dw9768_dev->standby = false;
+		ret = dw9768_init(dw9768_dev);
+		if (ret < 0)
+			goto fail;
+	}
+
+	return 0;
+
+fail:
+	dw9768_dev->standby = true;
+	regulator_disable(dw9768_dev->analog_regulator);
+
+	return ret;
+}
+
+/*
+ * 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 dw9768_update_hw(struct dw9768_device *dw9768_dev, u16 val)
+{
+	unsigned char i;
+	int ret;
+
+	char puSendCmdArray[2][2] = {
+		{DW9768_REG_DAC_MSB, (char)(val >> DW9768_DAC_SHIFT)},
+		{DW9768_REG_DAC_LSB, (char)(val & 0xFF)},
+	};
+
+	for (i = 0; i < (sizeof(puSendCmdArray) / sizeof(char)) /
+	     (sizeof(puSendCmdArray[0]) / sizeof(char)); i++) {
+		ret = dw9768_i2c_write(dw9768_dev, puSendCmdArray[i],
+				       DW9768_REG_VALUE_16BIT);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int dw9768_set_ctrl(struct v4l2_ctrl *ctrl)
+{
+	struct dw9768_device *dw9768_dev = to_dw9768_vcm(ctrl);
+
+	if (ctrl->id == V4L2_CID_FOCUS_ABSOLUTE)
+		return dw9768_update_hw(dw9768_dev, ctrl->val);
+
+	return 0;
+}
+
+static const struct v4l2_ctrl_ops dw9768_vcm_ctrl_ops = {
+	.s_ctrl = dw9768_set_ctrl,
+};
+
+static int
+dw9768_set_power(struct v4l2_subdev *subdev, int on)
+{
+	struct dw9768_device *dw9768_dev = sd_to_dw9768_vcm(subdev);
+	int ret = 0;
+
+	mutex_lock(&dw9768_dev->power_lock);
+
+	/*
+	 * If the power count is modified from 0 to != 0 or from != 0 to 0,
+	 * update the power state.
+	 */
+	if (dw9768_dev->power_count == !on) {
+		ret = on ? dw9768_power_on(dw9768_dev, true) :
+			dw9768_power_off(dw9768_dev, true);
+		if (ret < 0)
+			goto done;
+	}
+
+	/* Update the power count. */
+	dw9768_dev->power_count += on ? 1 : -1;
+	WARN_ON(dw9768_dev->power_count < 0);
+
+done:
+	mutex_unlock(&dw9768_dev->power_lock);
+	return ret;
+}
+
+static int dw9768_open(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
+{
+	return dw9768_set_power(sd, 1);
+}
+
+static int dw9768_close(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
+{
+	return dw9768_set_power(sd, 0);
+}
+
+static const struct v4l2_subdev_internal_ops dw9768_int_ops = {
+	.open = dw9768_open,
+	.close = dw9768_close,
+};
+
+static const struct v4l2_subdev_ops dw9768_ops = { };
+
+static void dw9768_subdev_cleanup(struct dw9768_device *dw9768_dev)
+{
+	v4l2_async_unregister_subdev(&dw9768_dev->sd);
+	v4l2_ctrl_handler_free(&dw9768_dev->ctrls);
+	media_entity_cleanup(&dw9768_dev->sd.entity);
+}
+
+static int dw9768_init_controls(struct dw9768_device *dw9768_dev)
+{
+	struct v4l2_ctrl_handler *hdl = &dw9768_dev->ctrls;
+	const struct v4l2_ctrl_ops *ops = &dw9768_vcm_ctrl_ops;
+
+	v4l2_ctrl_handler_init(hdl, 1);
+
+	v4l2_ctrl_new_std(hdl, ops, V4L2_CID_FOCUS_ABSOLUTE,
+			  0, DW9768_MAX_FOCUS_POS, DW9768_FOCUS_STEPS, 0);
+
+	if (hdl->error) {
+		dev_err(dw9768_dev->sd.dev, "%s fail error: 0x%x\n",
+			__func__, hdl->error);
+		return hdl->error;
+	}
+
+	dw9768_dev->sd.ctrl_handler = hdl;
+
+	return 0;
+}
+
+static int dw9768_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct dw9768_device *dw9768_dev;
+	int rval;
+
+	dw9768_dev = devm_kzalloc(&client->dev, sizeof(*dw9768_dev),
+				  GFP_KERNEL);
+	if (!dw9768_dev)
+		return -ENOMEM;
+
+	dw9768_dev->analog_regulator = devm_regulator_get(dev, "afvdd");
+	if (IS_ERR(dw9768_dev->analog_regulator)) {
+		dev_err(dev, "cannot get analog regulator\n");
+		return PTR_ERR(dw9768_dev->analog_regulator);
+	}
+
+	rval = regulator_set_voltage(dw9768_dev->analog_regulator,
+				     DW9768_VOLTAGE_ANALOG,
+				     DW9768_VOLTAGE_ANALOG);
+	if (rval < 0) {
+		dev_err(dev, "cannot set analog voltage\n");
+		return rval;
+	}
+
+	mutex_init(&dw9768_dev->power_lock);
+
+	v4l2_i2c_subdev_init(&dw9768_dev->sd, client, &dw9768_ops);
+	dw9768_dev->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
+	dw9768_dev->sd.internal_ops = &dw9768_int_ops;
+
+	rval = dw9768_init_controls(dw9768_dev);
+	if (rval)
+		goto err_cleanup;
+
+	rval = media_entity_pads_init(&dw9768_dev->sd.entity, 0, NULL);
+	if (rval < 0)
+		goto err_cleanup;
+
+	dw9768_dev->sd.entity.function = MEDIA_ENT_F_LENS;
+
+	rval = v4l2_async_register_subdev(&dw9768_dev->sd);
+	if (rval < 0)
+		goto err_cleanup;
+
+	pm_runtime_set_active(dev);
+	pm_runtime_enable(dev);
+	pm_runtime_idle(dev);
+
+	return 0;
+
+err_cleanup:
+	mutex_destroy(&dw9768_dev->power_lock);
+	dw9768_subdev_cleanup(dw9768_dev);
+	dev_err(dev, "Probe failed: %d\n", rval);
+	return rval;
+}
+
+static int dw9768_remove(struct i2c_client *client)
+{
+	struct v4l2_subdev *sd = i2c_get_clientdata(client);
+	struct dw9768_device *dw9768_dev = sd_to_dw9768_vcm(sd);
+
+	pm_runtime_disable(&client->dev);
+	dw9768_subdev_cleanup(dw9768_dev);
+
+	return 0;
+}
+
+/*
+ * This function sets the vcm position, so it consumes least current
+ * The lens position is gradually moved in units of DW9768_CTRL_STEPS,
+ * to make the movements smoothly.
+ */
+static int __maybe_unused dw9768_vcm_suspend(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct v4l2_subdev *sd = i2c_get_clientdata(client);
+	struct dw9768_device *dw9768_dev = sd_to_dw9768_vcm(sd);
+
+	if (!dw9768_dev->power_count)
+		return 0;
+
+	return dw9768_power_off(dw9768_dev, false);
+}
+
+/*
+ * 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 DW9768_CTRL_STEPS,
+ * to make the movements smoothly.
+ */
+static int __maybe_unused dw9768_vcm_resume(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct v4l2_subdev *sd = i2c_get_clientdata(client);
+	struct dw9768_device *dw9768_dev = sd_to_dw9768_vcm(sd);
+
+	if (!dw9768_dev->power_count)
+		return 0;
+
+	return dw9768_power_on(dw9768_dev, true);
+}
+
+static const struct i2c_device_id dw9768_id_table[] = {
+	{ DW9768_NAME, 0 },
+	{ { 0 } }
+};
+MODULE_DEVICE_TABLE(i2c, dw9768_id_table);
+
+static const struct of_device_id dw9768_of_table[] = {
+	{ .compatible = "dongwoon,dw9768" },
+	{ { 0 } }
+};
+MODULE_DEVICE_TABLE(of, dw9768_of_table);
+
+static const struct dev_pm_ops dw9768_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(dw9768_vcm_suspend, dw9768_vcm_resume)
+	SET_RUNTIME_PM_OPS(dw9768_vcm_suspend, dw9768_vcm_resume, NULL)
+};
+
+static struct i2c_driver dw9768_i2c_driver = {
+	.driver = {
+		.name = DW9768_NAME,
+		.pm = &dw9768_pm_ops,
+		.of_match_table = dw9768_of_table,
+	},
+	.probe_new  = dw9768_probe,
+	.remove = dw9768_remove,
+	.id_table = dw9768_id_table,
+};
+
+module_i2c_driver(dw9768_i2c_driver);
+
+MODULE_AUTHOR("Dongchun Zhu <dongchun.zhu@mediatek.com>");
+MODULE_DESCRIPTION("DW9768 VCM driver");
+MODULE_LICENSE("GPL v2");