Re: [PATCH] media: i2c: Add driver for DW9719 VCM

[Sakari Ailus <sakari.ailus@linux.intel.com>]

Hi Daniel,

Apologies for the late review.

On Sun, Nov 28, 2021 at 11:21:15PM +0000, Daniel Scally wrote:
> Add a driver for the DW9719 VCM. The driver creates a v4l2 subdevice
> and registers a control to set the desired focus.
> 
> Signed-off-by: Daniel Scally <djrscally@gmail.com>
> ---
>  MAINTAINERS                |   7 +
>  drivers/media/i2c/Kconfig  |  11 +
>  drivers/media/i2c/Makefile |   1 +
>  drivers/media/i2c/dw9719.c | 427 +++++++++++++++++++++++++++++++++++++
>  4 files changed, 446 insertions(+)
>  create mode 100644 drivers/media/i2c/dw9719.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 6e0763ff55db..99d2bc961bc0 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -5789,6 +5789,13 @@ T:	git git://linuxtv.org/media_tree.git
>  F:	Documentation/devicetree/bindings/media/i2c/dongwoon,dw9714.txt
>  F:	drivers/media/i2c/dw9714.c
>  
> +DONGWOON DW9719 LENS VOICE COIL DRIVER
> +M:	Daniel Scally <djrscally@gmail.com>
> +L:	linux-media@vger.kernel.org
> +S:	Maintained
> +T:	git git://linuxtv.org/media_tree.git
> +F:	drivers/media/i2c/dw9719.c
> +
>  DONGWOON DW9768 LENS VOICE COIL DRIVER
>  M:	Dongchun Zhu <dongchun.zhu@mediatek.com>
>  L:	linux-media@vger.kernel.org
> diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
> index 8761a90a7a86..096c9be6c402 100644
> --- a/drivers/media/i2c/Kconfig
> +++ b/drivers/media/i2c/Kconfig
> @@ -1465,6 +1465,17 @@ config VIDEO_DW9714
>  	  capability. This is designed for linear control of
>  	  voice coil motors, controlled via I2C serial interface.
>  
> +config VIDEO_DW9719
> +	tristate "DW9719 lens voice coil support"
> +	depends on I2C && VIDEO_V4L2
> +	select MEDIA_CONTROLLER
> +	select VIDEO_V4L2_SUBDEV_API
> +	select V4L2_ASYNC
> +	help
> +	  This is a driver for the DW9719 camera lens voice coil.
> +	  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
> diff --git a/drivers/media/i2c/Makefile b/drivers/media/i2c/Makefile
> index b01f6cd05ee8..ba8b31d79222 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-$(CONFIG_VIDEO_DW9719)  += dw9719.o
>  obj-$(CONFIG_VIDEO_DW9768)  += dw9768.o
>  obj-$(CONFIG_VIDEO_DW9807_VCM)  += dw9807-vcm.o
>  obj-$(CONFIG_VIDEO_ADV7170) += adv7170.o
> diff --git a/drivers/media/i2c/dw9719.c b/drivers/media/i2c/dw9719.c
> new file mode 100644
> index 000000000000..8451c75b696b
> --- /dev/null
> +++ b/drivers/media/i2c/dw9719.c
> @@ -0,0 +1,427 @@
> +// SPDX-License-Identifier: GPL-2.0
> +// Copyright (c) 2012 Intel Corporation
> +
> +/*
> + * Based on linux/modules/camera/drivers/media/i2c/imx/dw9719.c in this repo:
> + * https://github.com/ZenfoneArea/android_kernel_asus_zenfone5
> + */
> +
> +#include <asm/unaligned.h>
> +
> +#include <linux/delay.h>
> +#include <linux/i2c.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/types.h>
> +
> +#include <media/v4l2-common.h>
> +#include <media/v4l2-ctrls.h>
> +#include <media/v4l2-subdev.h>
> +
> +#define DW9719_MAX_FOCUS_POS	1023
> +#define DW9719_CTRL_STEPS	16
> +#define DW9719_CTRL_DELAY_US	1000
> +#define DELAY_MAX_PER_STEP_NS	(1000000 * 1023)
> +
> +#define DW9719_INFO			0
> +#define DW9719_ID			0xF1
> +#define DW9719_CONTROL			2
> +#define DW9719_VCM_CURRENT		3
> +
> +#define DW9719_MODE			6
> +#define DW9719_VCM_FREQ			7
> +
> +#define DW9719_MODE_SAC3		0x40
> +#define DW9719_DEFAULT_VCM_FREQ		0x60
> +#define DW9719_ENABLE_RINGING		0x02

I guess you could have defaults but these are probably specific to the
module (spring and lens) rather than to this chip (which is just a current
sink).

Still it'd be much better to have these bound to the platform. See e.g.

	Documentation/devicetree/bindings/media/i2c/dongwoon,dw9768.yaml

> +
> +#define NUM_REGULATORS			2
> +
> +#define to_dw9719_device(x) container_of(x, struct dw9719_device, sd)
> +
> +struct dw9719_device {
> +	struct device *dev;
> +	struct i2c_client *client;
> +	struct regulator_bulk_data regulators[NUM_REGULATORS];
> +	struct v4l2_subdev sd;
> +
> +	struct dw9719_v4l2_ctrls {
> +		struct v4l2_ctrl_handler handler;
> +		struct v4l2_ctrl *focus;
> +	} ctrls;
> +};
> +
> +static int dw9719_i2c_rd8(struct i2c_client *client, u8 reg, u8 *val)
> +{
> +	struct i2c_msg msg[2];
> +	u8 buf[2] = { reg };
> +	int ret;
> +
> +	msg[0].addr = client->addr;
> +	msg[0].flags = 0;
> +	msg[0].len = 1;
> +	msg[0].buf = buf;
> +
> +	msg[1].addr = client->addr;
> +	msg[1].flags = I2C_M_RD;
> +	msg[1].len = 1;
> +	msg[1].buf = &buf[1];
> +	*val = 0;
> +
> +	ret = i2c_transfer(client->adapter, msg, 2);
> +	if (ret < 0)
> +		return ret;
> +
> +	*val = buf[1];
> +
> +	return 0;
> +}
> +
> +static int dw9719_i2c_wr8(struct i2c_client *client, u8 reg, u8 val)
> +{
> +	struct i2c_msg msg;
> +	int ret;
> +
> +	u8 buf[2] = { reg, val };
> +
> +	msg.addr = client->addr;
> +	msg.flags = 0;
> +	msg.len = sizeof(buf);
> +	msg.buf = buf;
> +
> +	ret = i2c_transfer(client->adapter, &msg, 1);
> +
> +	return ret < 0 ? ret : 0;
> +}
> +
> +static int dw9719_i2c_wr16(struct i2c_client *client, u8 reg, u16 val)
> +{
> +	struct i2c_msg msg;
> +	u8 buf[3] = { reg };
> +	int ret;
> +
> +	put_unaligned_be16(val, buf + 1);
> +
> +	msg.addr = client->addr;
> +	msg.flags = 0;
> +	msg.len = sizeof(buf);
> +	msg.buf = buf;
> +
> +	ret = i2c_transfer(client->adapter, &msg, 1);
> +
> +	return ret < 0 ? ret : 0;
> +}
> +
> +static int dw9719_detect(struct dw9719_device *dw9719)
> +{
> +	int ret;
> +	u8 val;
> +
> +	ret = dw9719_i2c_rd8(dw9719->client, DW9719_INFO, &val);
> +	if (ret < 0)
> +		return ret;
> +
> +	if (val != DW9719_ID) {
> +		dev_err(dw9719->dev, "Failed to detect correct id\n");
> +		ret = -ENXIO;
> +	}
> +
> +	return 0;
> +}
> +
> +static int dw9719_power_down(struct dw9719_device *dw9719)
> +{
> +	return regulator_bulk_disable(NUM_REGULATORS, dw9719->regulators);
> +}
> +
> +static int dw9719_power_up(struct dw9719_device *dw9719)
> +{
> +	int ret;
> +
> +	ret = regulator_bulk_enable(NUM_REGULATORS, dw9719->regulators);
> +	if (ret)
> +		return ret;
> +
> +	/* Jiggle SCL pin to wake up device */
> +	ret = dw9719_i2c_wr8(dw9719->client, DW9719_CONTROL, 1);
> +
> +	/* Need 100us to transit from SHUTDOWN to STANDBY*/
> +	usleep_range(100, 1000);
> +
> +	ret = dw9719_i2c_wr8(dw9719->client, DW9719_CONTROL,
> +			     DW9719_ENABLE_RINGING);
> +	if (ret < 0)
> +		goto fail_powerdown;
> +
> +	ret = dw9719_i2c_wr8(dw9719->client, DW9719_MODE, DW9719_MODE_SAC3);
> +	if (ret < 0)
> +		goto fail_powerdown;
> +
> +	ret = dw9719_i2c_wr8(dw9719->client, DW9719_VCM_FREQ,
> +			     DW9719_DEFAULT_VCM_FREQ);
> +	if (ret < 0)
> +		goto fail_powerdown;
> +
> +	return 0;
> +
> +fail_powerdown:
> +	dw9719_power_down(dw9719);
> +	return ret;
> +}
> +
> +static int dw9719_t_focus_abs(struct dw9719_device *dw9719, s32 value)
> +{
> +	int ret;
> +
> +	value = clamp(value, 0, DW9719_MAX_FOCUS_POS);
> +	ret = dw9719_i2c_wr16(dw9719->client, DW9719_VCM_CURRENT, value);
> +	if (ret < 0)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +static int dw9719_set_ctrl(struct v4l2_ctrl *ctrl)
> +{
> +	struct dw9719_device *dw9719 = container_of(ctrl->handler,
> +						    struct dw9719_device,
> +						    ctrls.handler);
> +	int ret;
> +
> +	/* Only apply changes to the controls if the device is powered up */
> +	if (!pm_runtime_get_if_in_use(dw9719->dev))
> +		return 0;
> +
> +	switch (ctrl->id) {
> +	case V4L2_CID_FOCUS_ABSOLUTE:
> +		ret = dw9719_t_focus_abs(dw9719, ctrl->val);
> +		break;
> +	default:
> +		ret = -EINVAL;
> +	}
> +
> +	pm_runtime_put(dw9719->dev);
> +
> +	return ret;
> +}
> +
> +static const struct v4l2_ctrl_ops dw9719_ctrl_ops = {
> +	.s_ctrl = dw9719_set_ctrl,
> +};
> +
> +static int __maybe_unused dw9719_suspend(struct device *dev)
> +{
> +	struct v4l2_subdev *sd = dev_get_drvdata(dev);
> +	struct dw9719_device *dw9719 = to_dw9719_device(sd);
> +	int ret;
> +	int val;
> +
> +	for (val = dw9719->ctrls.focus->val; val >= 0;
> +	     val -= DW9719_CTRL_STEPS) {
> +		ret = dw9719_t_focus_abs(dw9719, val);
> +		if (ret)
> +			return ret;
> +
> +		usleep_range(DW9719_CTRL_DELAY_US, DW9719_CTRL_DELAY_US + 10);
> +	}
> +
> +	return dw9719_power_down(dw9719);
> +}
> +
> +static int __maybe_unused dw9719_resume(struct device *dev)
> +{
> +	struct v4l2_subdev *sd = dev_get_drvdata(dev);
> +	struct dw9719_device *dw9719 = to_dw9719_device(sd);
> +	int current_focus = dw9719->ctrls.focus->val;
> +	int ret;
> +	int val;
> +
> +	ret = dw9719_power_up(dw9719);
> +	if (ret)
> +		return ret;
> +
> +	for (val = current_focus % DW9719_CTRL_STEPS; val < current_focus;
> +	     val += DW9719_CTRL_STEPS) {
> +		ret = dw9719_t_focus_abs(dw9719, val);
> +		if (ret)
> +			goto err_power_down;
> +
> +		usleep_range(DW9719_CTRL_DELAY_US, DW9719_CTRL_DELAY_US + 10);
> +	}
> +
> +	return 0;
> +
> +err_power_down:
> +	dw9719_power_down(dw9719);
> +	return ret;
> +}
> +
> +static int dw9719_open(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
> +{
> +	return pm_runtime_resume_and_get(sd->dev);
> +}
> +
> +static int dw9719_close(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
> +{
> +	pm_runtime_put(sd->dev);
> +
> +	return 0;
> +}
> +
> +static const struct v4l2_subdev_internal_ops dw9719_internal_ops = {
> +	.open = dw9719_open,
> +	.close = dw9719_close,
> +};
> +
> +static int dw9719_init_controls(struct dw9719_device *dw9719)
> +{
> +	const struct v4l2_ctrl_ops *ops = &dw9719_ctrl_ops;
> +	int ret;
> +
> +	ret = v4l2_ctrl_handler_init(&dw9719->ctrls.handler, 1);
> +	if (ret)
> +		return ret;
> +
> +	dw9719->ctrls.focus = v4l2_ctrl_new_std(&dw9719->ctrls.handler, ops,
> +						V4L2_CID_FOCUS_ABSOLUTE, 0,
> +						DW9719_MAX_FOCUS_POS, 1, 0);
> +
> +	if (dw9719->ctrls.handler.error) {
> +		dev_err(dw9719->dev, "Error initialising v4l2 ctrls\n");
> +		ret = dw9719->ctrls.handler.error;
> +		goto err_free_handler;
> +	}
> +
> +	dw9719->sd.ctrl_handler = &dw9719->ctrls.handler;
> +
> +	return ret;
> +
> +err_free_handler:
> +	v4l2_ctrl_handler_free(&dw9719->ctrls.handler);
> +	return ret;
> +}
> +
> +static const struct v4l2_subdev_ops dw9719_ops = { };
> +
> +static int dw9719_probe(struct i2c_client *client)
> +{
> +	struct dw9719_device *dw9719;
> +	int ret;
> +
> +	dw9719 = devm_kzalloc(&client->dev, sizeof(*dw9719), GFP_KERNEL);
> +	if (!dw9719)
> +		return -ENOMEM;
> +
> +	dw9719->client = client;
> +	dw9719->dev = &client->dev;
> +
> +	dw9719->regulators[0].supply = "vdd";
> +	/*
> +	 * The DW9719 has only the 1 VDD voltage input, but some PMICs such as
> +	 * the TPS68470 PMIC have I2C passthrough capability, to disconnect the
> +	 * sensor's I2C pins from the I2C bus when the sensors VSIO (Sensor-IO)
> +	 * is off, because some sensors then short these pins to ground;
> +	 * and the DW9719 might sit behind this passthrough, this it needs to
> +	 * enable VSIO as that will also enable the I2C passthrough.
> +	 */
> +	dw9719->regulators[1].supply = "vsio";

Urgh.

That should have been handled in ACPI.

Do you know if such a sensor actually exists or is this motivated by the
PMIC chip's feature?

> +
> +	ret = devm_regulator_bulk_get(&client->dev, NUM_REGULATORS,
> +				      dw9719->regulators);
> +	if (ret)
> +		return dev_err_probe(&client->dev, ret, "getting regulators\n");
> +
> +	v4l2_i2c_subdev_init(&dw9719->sd, client, &dw9719_ops);
> +	dw9719->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
> +	dw9719->sd.internal_ops = &dw9719_internal_ops;
> +
> +	ret = dw9719_init_controls(dw9719);
> +	if (ret)
> +		return ret;
> +
> +	ret = media_entity_pads_init(&dw9719->sd.entity, 0, NULL);
> +	if (ret < 0)
> +		goto err_free_ctrl_handler;
> +
> +	dw9719->sd.entity.function = MEDIA_ENT_F_LENS;
> +
> +	/*
> +	 * We need the driver to work in the event that pm runtime is disable in
> +	 * the kernel, so power up and verify the chip now. In the event that
> +	 * runtime pm is disabled this will leave the chip on, so that the lens
> +	 * will work.
> +	 */
> +
> +	ret = dw9719_power_up(dw9719);
> +	if (ret)
> +		goto err_cleanup_media;
> +
> +	ret = dw9719_detect(dw9719);
> +	if (ret)
> +		goto err_powerdown;
> +
> +	pm_runtime_set_active(&client->dev);
> +	pm_runtime_get_noresume(&client->dev);
> +	pm_runtime_enable(&client->dev);
> +
> +	ret = v4l2_async_register_subdev(&dw9719->sd);
> +	if (ret < 0)
> +		goto err_pm_runtime;
> +
> +	pm_runtime_set_autosuspend_delay(&client->dev, 1000);
> +	pm_runtime_use_autosuspend(&client->dev);
> +	pm_runtime_put_autosuspend(&client->dev);
> +
> +	return ret;
> +
> +err_pm_runtime:
> +	pm_runtime_disable(&client->dev);
> +	pm_runtime_put_noidle(&client->dev);
> +err_powerdown:
> +	dw9719_power_down(dw9719);
> +err_cleanup_media:
> +	media_entity_cleanup(&dw9719->sd.entity);
> +err_free_ctrl_handler:
> +	v4l2_ctrl_handler_free(&dw9719->ctrls.handler);
> +
> +	return ret;
> +}
> +
> +static int dw9719_remove(struct i2c_client *client)
> +{
> +	struct v4l2_subdev *sd = i2c_get_clientdata(client);
> +	struct dw9719_device *dw9719 = container_of(sd, struct dw9719_device,
> +						    sd);
> +
> +	pm_runtime_disable(&client->dev);
> +	v4l2_async_unregister_subdev(sd);
> +	v4l2_ctrl_handler_free(&dw9719->ctrls.handler);
> +	media_entity_cleanup(&dw9719->sd.entity);
> +
> +	return 0;
> +}
> +
> +static const struct i2c_device_id dw9719_id_table[] = {
> +	{ "dw9719" },

Hmm. Do you need the ID table?

> +	{ }
> +};
> +MODULE_DEVICE_TABLE(i2c, dw9719_id_table);
> +
> +static const struct dev_pm_ops dw9719_pm_ops = {
> +	SET_RUNTIME_PM_OPS(dw9719_suspend, dw9719_resume, NULL)
> +};
> +
> +static struct i2c_driver dw9719_i2c_driver = {
> +	.driver = {
> +		.name = "dw9719",
> +		.pm = &dw9719_pm_ops,
> +	},
> +	.probe_new = dw9719_probe,
> +	.remove = dw9719_remove,
> +	.id_table = dw9719_id_table,
> +};
> +module_i2c_driver(dw9719_i2c_driver);
> +
> +MODULE_AUTHOR("Daniel Scally <djrscally@gmail.com>");
> +MODULE_DESCRIPTION("DW9719 VCM Driver");
> +MODULE_LICENSE("GPL");

-- 
Kind regards,

Sakari Ailus