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References: <20230915165946.4183839-1-kieran.bingham@ideasonboard.com> <20230915165946.4183839-3-kieran.bingham@ideasonboard.com>
In-Reply-To: <20230915165946.4183839-3-kieran.bingham@ideasonboard.com>
From:   Dave Stevenson <dave.stevenson@raspberrypi.com>
Date:   Fri, 15 Sep 2023 18:44:02 +0100
Message-ID: <CAPY8ntCeo2LVCRbcrx8q+RSvo2B+KcUYRCAkoHCeVywioknM2A@mail.gmail.com>
Subject: Re: [PATCH 2/2] media: i2c: Add ROHM BU64754 Camera Autofocus Actuator
To:     Kieran Bingham <kieran.bingham@ideasonboard.com>
Cc:     linux-media@vger.kernel.org,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Liam Girdwood <lgirdwood@gmail.com>,
        Mark Brown <broonie@kernel.org>,
        Sakari Ailus <sakari.ailus@linux.intel.com>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Hans de Goede <hdegoede@redhat.com>,
        Andy Shevchenko <andy.shevchenko@gmail.com>,
        Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>,
        Marco Felsch <m.felsch@pengutronix.de>,
        Gerald Loacker <gerald.loacker@wolfvision.net>,
        Bingbu Cao <bingbu.cao@intel.com>,
        Daniel Scally <djrscally@gmail.com>,
        Linus Walleij <linus.walleij@linaro.org>,
        open list <linux-kernel@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

Hi Kieran

On Fri, 15 Sept 2023 at 18:02, Kieran Bingham
<kieran.bingham@ideasonboard.com> wrote:
>
> Add support for the ROHM BU64754 Motor Driver for Camera Autofocus. A
> V4L2 Subdevice is registered and provides a single
> V4L2_CID_FOCUS_ABSOLUTE control.
>
> Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
> ---
>  MAINTAINERS                 |   1 +
>  drivers/media/i2c/Kconfig   |  13 ++
>  drivers/media/i2c/Makefile  |   1 +
>  drivers/media/i2c/bu64754.c | 308 ++++++++++++++++++++++++++++++++++++
>  4 files changed, 323 insertions(+)
>  create mode 100644 drivers/media/i2c/bu64754.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index f43e0ffcaf56..fd244560c317 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -18576,6 +18576,7 @@ L:      linux-media@vger.kernel.org
>  S:     Maintained
>  T:     git git://linuxtv.org/media_tree.git
>  F:     Documentation/devicetree/bindings/media/i2c/rohm,bu64754.yaml
> +F:     drivers/media/i2c/bu64754.c
>
>  ROHM MULTIFUNCTION BD9571MWV-M PMIC DEVICE DRIVERS
>  M:     Marek Vasut <marek.vasut+renesas@gmail.com>
> diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
> index 74ff833ff48c..b7b8004816ed 100644
> --- a/drivers/media/i2c/Kconfig
> +++ b/drivers/media/i2c/Kconfig
> @@ -641,6 +641,19 @@ config VIDEO_AK7375
>           capability. This is designed for linear control of
>           voice coil motors, controlled via I2C serial interface.
>
> +config VIDEO_BU64754
> +       tristate "BU64754 Motor Driver for Camera Autofocus"
> +       depends on I2C && VIDEO_DEV
> +       select MEDIA_CONTROLLER
> +       select VIDEO_V4L2_SUBDEV_API
> +       select V4L2_ASYNC
> +       select V4L2_CCI_I2C
> +       help
> +         This is a driver for the BU64754 Motor Driver for Camera
> +         Autofocus. The BU64754 is an actuator driver IC which can
> +         control the actuator position precisely using an internal
> +         Hall Sensor.

I can't find any data on this driver.
Is it still expecting a VCM and hence near instantaneous movement? I
was noting your comment on the hall sensor and thinking you
potentially needed to be able to report whether the target position
had been reached or not. Michael's series at [1] was trying to address
that.

[1] https://patchwork.linuxtv.org/project/linux-media/cover/20230406-feature-controls-lens-v2-0-faa8ad2bc404@wolfvision.net/

> +
>  config VIDEO_DW9714
>         tristate "DW9714 lens voice coil support"
>         depends on I2C && VIDEO_DEV
> diff --git a/drivers/media/i2c/Makefile b/drivers/media/i2c/Makefile
> index 80b00d39b48f..e62aa0df7b1a 100644
> --- a/drivers/media/i2c/Makefile
> +++ b/drivers/media/i2c/Makefile
> @@ -22,6 +22,7 @@ obj-$(CONFIG_VIDEO_AR0521) += ar0521.o
>  obj-$(CONFIG_VIDEO_BT819) += bt819.o
>  obj-$(CONFIG_VIDEO_BT856) += bt856.o
>  obj-$(CONFIG_VIDEO_BT866) += bt866.o
> +obj-$(CONFIG_VIDEO_BU64754) += bu64754.o
>  obj-$(CONFIG_VIDEO_CCS) += ccs/
>  obj-$(CONFIG_VIDEO_CCS_PLL) += ccs-pll.o
>  obj-$(CONFIG_VIDEO_CS3308) += cs3308.o
> diff --git a/drivers/media/i2c/bu64754.c b/drivers/media/i2c/bu64754.c
> new file mode 100644
> index 000000000000..3367b6f17660
> --- /dev/null
> +++ b/drivers/media/i2c/bu64754.c
> @@ -0,0 +1,308 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * The BU64754 is an actuator driver IC which can control the
> + * actuator position precisely using an internal Hall Sensor.
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/i2c.h>
> +#include <linux/module.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/regulator/consumer.h>
> +
> +#include <media/v4l2-cci.h>
> +#include <media/v4l2-ctrls.h>
> +#include <media/v4l2-device.h>
> +
> +#define BU64754_REG_ACTIVE     CCI_REG16(0x07)
> +#define BU64754_ACTIVE_MODE    0x8080
> +
> +#define BU64754_REG_SERVE      CCI_REG16(0xd9)
> +#define BU64754_SERVE_ON       0x0404
> +
> +#define BU64754_REG_POSITION   CCI_REG16(0x45)
> +#define BU64753_POSITION_MAX   1023 /* 0x3ff */
> +
> +#define BU64754_POWER_ON_DELAY 800 /* uS : t1, t3 */
> +
> +struct bu64754 {
> +       struct device *dev;
> +
> +       struct v4l2_ctrl_handler ctrls_vcm;
> +       struct v4l2_subdev sd;
> +       struct regmap *cci;
> +
> +       u16 current_val;
> +       struct regulator *vdd;
> +       struct notifier_block notifier;
> +};
> +
> +static inline struct bu64754 *sd_to_bu64754(struct v4l2_subdev *subdev)
> +{
> +       return container_of(subdev, struct bu64754, sd);
> +}
> +
> +static int bu64754_set(struct bu64754 *bu64754, u16 position)
> +{
> +       int ret;
> +
> +       ret = cci_write(bu64754->cci, BU64754_REG_POSITION, position, NULL);
> +       if (ret) {
> +               dev_err(bu64754->dev, "Set position failed ret=%d\n", ret);
> +               return ret;
> +       }
> +
> +       return 0;
> +}
> +
> +static int bu64754_active(struct bu64754 *bu64754)
> +{
> +       int ret;
> +
> +       /* Power on */
> +       ret = cci_write(bu64754->cci, BU64754_REG_ACTIVE, BU64754_ACTIVE_MODE,
> +                       NULL);
> +       if (ret < 0) {
> +               dev_err(bu64754->dev, "Failed to set active mode ret = %d\n",
> +                       ret);
> +               return ret;
> +       }
> +
> +       /* Serve on */
> +       ret = cci_write(bu64754->cci, BU64754_REG_SERVE, BU64754_SERVE_ON,
> +                       NULL);
> +       if (ret < 0) {
> +               dev_err(bu64754->dev, "Failed to enable serve ret = %d\n",
> +                       ret);
> +               return ret;
> +       }
> +
> +       return bu64754_set(bu64754, bu64754->current_val);
> +}
> +
> +static int bu64754_standby(struct bu64754 *bu64754)
> +{
> +       int ret;
> +
> +       cci_write(bu64754->cci, BU64754_REG_ACTIVE, 0, &ret);
> +       if (ret < 0)
> +               dev_err(bu64754->dev, "Failed to set active mode ret = %d\n",
> +                       ret);
> +
> +       return ret;
> +}
> +
> +static int bu64754_regulator_event(struct notifier_block *nb,
> +                                  unsigned long action, void *data)
> +{
> +       struct bu64754 *bu64754 = container_of(nb, struct bu64754, notifier);
> +
> +       if (action & REGULATOR_EVENT_ENABLE) {
> +               /*
> +                * Initialisation delay between VDD low->high and availability
> +                * i2c operation.
> +                */
> +               usleep_range(BU64754_POWER_ON_DELAY,
> +                            BU64754_POWER_ON_DELAY + 100);
> +
> +               bu64754_active(bu64754);
> +       } else if (action & REGULATOR_EVENT_PRE_DISABLE) {
> +               bu64754_standby(bu64754);
> +       }

Presumably this is based on the assumption that the same regulator
controls sensor and lens, so when the sensor is powered up the lens
position gets restored.
I'm sure when I suggested doing the same previously it was shot down
in flames ... found it [2]

Personally I think it makes sense that the lens powers up
automagically, and have almost exactly the same code as this in a
couple of our VCM drivers, but others disagree.

  Dave

[2] https://lore.kernel.org/all/CAPY8ntBZpZjecHNCMf-eMefcp2EgmbqkXMt4p=UeOe0n-o8WrA@mail.gmail.com/

> +
> +       return 0;
> +}
> +
> +static int bu64754_set_ctrl(struct v4l2_ctrl *ctrl)
> +{
> +       struct bu64754 *bu64754 = container_of(ctrl->handler,
> +               struct bu64754, ctrls_vcm);
> +
> +       if (ctrl->id == V4L2_CID_FOCUS_ABSOLUTE) {
> +               bu64754->current_val = ctrl->val;
> +               return bu64754_set(bu64754, ctrl->val);
> +       }
> +
> +       return -EINVAL;
> +}
> +
> +static const struct v4l2_ctrl_ops bu64754_vcm_ctrl_ops = {
> +       .s_ctrl = bu64754_set_ctrl,
> +};
> +
> +static int bu64754_open(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
> +{
> +       return pm_runtime_resume_and_get(sd->dev);
> +}
> +
> +static int bu64754_close(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
> +{
> +       pm_runtime_put(sd->dev);
> +       return 0;
> +}
> +
> +static const struct v4l2_subdev_internal_ops bu64754_int_ops = {
> +       .open = bu64754_open,
> +       .close = bu64754_close,
> +};
> +
> +static const struct v4l2_subdev_ops bu64754_ops = { };
> +
> +static void bu64754_subdev_cleanup(struct bu64754 *bu64754)
> +{
> +       v4l2_async_unregister_subdev(&bu64754->sd);
> +       v4l2_ctrl_handler_free(&bu64754->ctrls_vcm);
> +       media_entity_cleanup(&bu64754->sd.entity);
> +}
> +
> +static int bu64754_init_controls(struct bu64754 *bu64754)
> +{
> +       struct v4l2_ctrl_handler *hdl = &bu64754->ctrls_vcm;
> +       const struct v4l2_ctrl_ops *ops = &bu64754_vcm_ctrl_ops;
> +
> +       v4l2_ctrl_handler_init(hdl, 1);
> +
> +       v4l2_ctrl_new_std(hdl, ops, V4L2_CID_FOCUS_ABSOLUTE,
> +                         0, BU64753_POSITION_MAX, 1, 0);
> +
> +       bu64754->current_val = 0;
> +
> +       bu64754->sd.ctrl_handler = hdl;
> +       if (hdl->error) {
> +               dev_err(bu64754->dev, "%s fail error: 0x%x\n",
> +                       __func__, hdl->error);
> +               return hdl->error;
> +       }
> +
> +       return 0;
> +}
> +
> +static int bu64754_probe(struct i2c_client *client)
> +{
> +       struct bu64754 *bu64754;
> +       int ret;
> +
> +       bu64754 = devm_kzalloc(&client->dev, sizeof(*bu64754), GFP_KERNEL);
> +       if (!bu64754)
> +               return -ENOMEM;
> +
> +       bu64754->dev = &client->dev;
> +
> +       bu64754->cci = devm_cci_regmap_init_i2c(client, 8);
> +       if (IS_ERR(bu64754->cci)) {
> +               dev_err(bu64754->dev, "Failed to initialize CCI\n");
> +               return PTR_ERR(bu64754->cci);
> +       }
> +
> +       bu64754->vdd = devm_regulator_get_optional(&client->dev, "vdd");
> +       if (IS_ERR(bu64754->vdd)) {
> +               if (PTR_ERR(bu64754->vdd) != -ENODEV)
> +                       return PTR_ERR(bu64754->vdd);
> +
> +               bu64754->vdd = NULL;
> +       } else {
> +               bu64754->notifier.notifier_call = bu64754_regulator_event;
> +
> +               ret = regulator_register_notifier(bu64754->vdd,
> +                                                 &bu64754->notifier);
> +               if (ret) {
> +                       dev_err(bu64754->dev,
> +                               "could not register regulator notifier\n");
> +                       return ret;
> +               }
> +       }
> +
> +       v4l2_i2c_subdev_init(&bu64754->sd, client, &bu64754_ops);
> +       bu64754->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
> +       bu64754->sd.internal_ops = &bu64754_int_ops;
> +       bu64754->sd.entity.function = MEDIA_ENT_F_LENS;
> +
> +       ret = bu64754_init_controls(bu64754);
> +       if (ret)
> +               goto err_cleanup;
> +
> +       ret = media_entity_pads_init(&bu64754->sd.entity, 0, NULL);
> +       if (ret < 0)
> +               goto err_cleanup;
> +
> +       ret = v4l2_async_register_subdev(&bu64754->sd);
> +       if (ret < 0)
> +               goto err_cleanup;
> +
> +       if (!bu64754->vdd)
> +               pm_runtime_set_active(&client->dev);
> +
> +       pm_runtime_enable(&client->dev);
> +       pm_runtime_idle(&client->dev);
> +
> +       return 0;
> +
> +err_cleanup:
> +       v4l2_ctrl_handler_free(&bu64754->ctrls_vcm);
> +       media_entity_cleanup(&bu64754->sd.entity);
> +
> +       return ret;
> +}
> +
> +static void bu64754_remove(struct i2c_client *client)
> +{
> +       struct v4l2_subdev *sd = i2c_get_clientdata(client);
> +       struct bu64754 *bu64754 = sd_to_bu64754(sd);
> +
> +       if (bu64754->vdd)
> +               regulator_unregister_notifier(bu64754->vdd,
> +                                             &bu64754->notifier);
> +
> +       pm_runtime_disable(&client->dev);
> +
> +       bu64754_subdev_cleanup(bu64754);
> +}
> +
> +static int __maybe_unused bu64754_vcm_suspend(struct device *dev)
> +{
> +       struct i2c_client *client = to_i2c_client(dev);
> +       struct v4l2_subdev *sd = i2c_get_clientdata(client);
> +       struct bu64754 *bu64754 = sd_to_bu64754(sd);
> +
> +       if (bu64754->vdd)
> +               return regulator_disable(bu64754->vdd);
> +
> +       return bu64754_standby(bu64754);
> +}
> +
> +static int  __maybe_unused bu64754_vcm_resume(struct device *dev)
> +{
> +       struct i2c_client *client = to_i2c_client(dev);
> +       struct v4l2_subdev *sd = i2c_get_clientdata(client);
> +       struct bu64754 *bu64754 = sd_to_bu64754(sd);
> +
> +       if (bu64754->vdd)
> +               return regulator_enable(bu64754->vdd);
> +
> +       return bu64754_active(bu64754);
> +}
> +
> +static const struct of_device_id bu64754_of_table[] = {
> +       { .compatible = "rohm,bu64754", },
> +       { /* sentinel */ }
> +};
> +
> +MODULE_DEVICE_TABLE(of, bu64754_of_table);
> +
> +static SIMPLE_DEV_PM_OPS(bu64754_pm, bu64754_vcm_suspend, bu64754_vcm_resume);
> +
> +static struct i2c_driver bu64754_i2c_driver = {
> +       .driver = {
> +               .name = "bu64754",
> +               .pm = &bu64754_pm,
> +               .of_match_table = bu64754_of_table,
> +       },
> +       .probe = bu64754_probe,
> +       .remove = bu64754_remove,
> +};
> +
> +module_i2c_driver(bu64754_i2c_driver);
> +
> +MODULE_AUTHOR("Kieran Bingham <kieran.bingham@ideasonboard.com>");
> +MODULE_DESCRIPTION("ROHM BU64754 VCM driver");
> +MODULE_LICENSE("GPL");
> --
> 2.34.1
>