Hi Bingbu,
Please see a couple of comments below.
> -----Original Message-----
> From: Cao, Bingbu
> Sent: Monday, June 04, 2018 2:00 AM
> To: linux-media@xxxxxxxxxxxxxxx
> Cc: sakari.ailus@xxxxxxxxxxxxxxx; tfiga@xxxxxxxxxx; jacopo@xxxxxxxxxx;
> Mani, Rajmohan <rajmohan.mani@xxxxxxxxx>; bingbu.cao@xxxxxxxxxxxxxxx;
> Qiu, Tian Shu <tian.shu.qiu@xxxxxxxxx>; Zheng, Jian Xu
> <jian.xu.zheng@xxxxxxxxx>
> Subject: [PATCH v3 2/2] media: ak7375: Add ak7375 lens voice coil driver
>
> From: Bingbu Cao <bingbu.cao@xxxxxxxxx>
>
> Add a v4l2 sub-device driver for the ak7375 lens voice coil.
> This is a voice coil module using the i2c bus to control the focus position.
>
> ak7375 can write multiple bytes of data at a time. If more data is received
> instead of the stop condition after receiving one byte of data, the address
> inside the chip is automatically incremented and the data is written into the
> next address.
>
> The ak7375 can control the position with 12 bits value and consists of two 8 bit
> registers show as below:
> register 0x00(AK7375_REG_POSITION):
> +---+---+---+---+---+---+---+---+
> |D11|D10|D09|D08|D07|D06|D05|D04|
> +---+---+---+---+---+---+---+---+
> register 0x01:
> +---+---+---+---+---+---+---+---+
> |D03|D02|D01|D00|---|---|---|---|
> +---+---+---+---+---+---+---+---+
>
> This driver support :
> - set ak7375 to standby mode once suspend and
> turn it back to active if resume
> - set the position via V4L2_CID_FOCUS_ABSOLUTE ctrl
>
> Signed-off-by: Tianshu Qiu <tian.shu.qiu@xxxxxxxxx>
> Signed-off-by: Bingbu Cao <bingbu.cao@xxxxxxxxx>
>
> ---
> Changes from v1:
> - correct i2c write
> - add media_entity_pads_init() into probe
> - move the MAINTAINERs change into dt-bindings change
> - correct the compatible string
> ---
> ---
> drivers/media/i2c/Kconfig | 10 ++
> drivers/media/i2c/Makefile | 1 +
> drivers/media/i2c/ak7375.c | 278
> +++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 289 insertions(+)
> create mode 100644 drivers/media/i2c/ak7375.c
>
> diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig index
> 341452fe98df..ff3cb5afb0e1 100644
> --- a/drivers/media/i2c/Kconfig
> +++ b/drivers/media/i2c/Kconfig
> @@ -326,6 +326,16 @@ config VIDEO_AD5820
> This is a driver for the AD5820 camera lens voice coil.
> It is used for example in Nokia N900 (RX-51).
>
> +config VIDEO_AK7375
> + tristate "AK7375 lens voice coil support"
> + depends on I2C && VIDEO_V4L2 && MEDIA_CONTROLLER
> + depends on VIDEO_V4L2_SUBDEV_API
> + help
> + This is a driver for the AK7375 camera lens voice coil.
> + AK7375 is a 12 bit DAC with 120mA output current sink
> + capability. This is designed for linear control of
> + voice coil motors, controlled via I2C serial interface.
> +
> config VIDEO_DW9714
> tristate "DW9714 lens voice coil support"
> depends on I2C && VIDEO_V4L2 && MEDIA_CONTROLLER diff --git
> a/drivers/media/i2c/Makefile b/drivers/media/i2c/Makefile index
> d679d57cd3b3..05b97e319ea9 100644
> --- a/drivers/media/i2c/Makefile
> +++ b/drivers/media/i2c/Makefile
> @@ -23,6 +23,7 @@ obj-$(CONFIG_VIDEO_SAA7127) += saa7127.o
> obj-$(CONFIG_VIDEO_SAA7185) += saa7185.o
> obj-$(CONFIG_VIDEO_SAA6752HS) += saa6752hs.o
> obj-$(CONFIG_VIDEO_AD5820) += ad5820.o
> +obj-$(CONFIG_VIDEO_AK7375) += ak7375.o
> obj-$(CONFIG_VIDEO_DW9714) += dw9714.o
> obj-$(CONFIG_VIDEO_ADV7170) += adv7170.o
> obj-$(CONFIG_VIDEO_ADV7175) += adv7175.o diff --git
> a/drivers/media/i2c/ak7375.c b/drivers/media/i2c/ak7375.c new file mode
> 100644 index 000000000000..94bcadae4258
> --- /dev/null
> +++ b/drivers/media/i2c/ak7375.c
> @@ -0,0 +1,278 @@
> +// SPDX-License-Identifier: GPL-2.0
> +// Copyright (C) 2018 Intel Corporation
> +
> +#include <linux/acpi.h>
> +#include <linux/delay.h>
> +#include <linux/i2c.h>
> +#include <linux/module.h>
> +#include <linux/pm_runtime.h>
> +#include <media/v4l2-ctrls.h>
> +#include <media/v4l2-device.h>
> +
> +#define AK7375_MAX_FOCUS_POS 4095
> +/*
> + * This sets the minimum granularity for the focus positions.
> + * A value of 1 gives maximum accuracy for a desired focus position */
> +#define AK7375_FOCUS_STEPS 1
> +/*
> + * This acts as the minimum granularity of lens movement.
> + * Keep this value power of 2, so the control steps can be
> + * uniformly adjusted for gradual lens movement, with desired
> + * number of control steps.
> + */
> +#define AK7375_CTRL_STEPS 64
> +#define AK7375_CTRL_DELAY_US 1000
> +
> +#define AK7375_REG_POSITION 0x0
> +#define AK7375_REG_CONT 0x2
> +#define AK7375_MODE_ACTIVE 0x0
> +#define AK7375_MODE_STANDBY 0x40
> +
> +/* ak7375 device structure */
> +struct ak7375_device {
> + struct v4l2_ctrl_handler ctrls_vcm;
> + struct v4l2_subdev sd;
> + struct v4l2_ctrl *focus;
> +};
> +
> +static inline struct ak7375_device *to_ak7375_vcm(struct v4l2_ctrl
> +*ctrl) {
> + return container_of(ctrl->handler, struct ak7375_device, ctrls_vcm); }
> +
> +static inline struct ak7375_device *sd_to_ak7375_vcm(struct v4l2_subdev
> +*subdev) {
> + return container_of(subdev, struct ak7375_device, sd); }
> +
> +static int ak7375_i2c_write(struct ak7375_device *ak7375,
> + u8 addr, u16 data, int size)
> +{
> + struct i2c_client *client = v4l2_get_subdevdata(&ak7375->sd);
> + int ret;
> + u8 buf[3];
> +
> + if (size != 1 && size != 2)
> + return -EINVAL;
> + buf[0] = addr;
> + buf[size] = data & 0xff;
> + if (size == 2)
> + buf[1] = (data >> 8) & 0xff;
> + ret = i2c_master_send(client, (const char *)buf, size + 1);
> + if (ret < 0)
> + return ret;
> + if (ret != size + 1)
> + return -EIO;
> + return 0;
> +}
> +
> +static int ak7375_set_ctrl(struct v4l2_ctrl *ctrl) {
> + struct ak7375_device *dev_vcm = to_ak7375_vcm(ctrl);
> +
> + if (ctrl->id == V4L2_CID_FOCUS_ABSOLUTE)
> + return ak7375_i2c_write(dev_vcm, AK7375_REG_POSITION,
> + ctrl->val << 4, 2);
> +
> + return -EINVAL;
> +}
> +
> +static const struct v4l2_ctrl_ops ak7375_vcm_ctrl_ops = {
> + .s_ctrl = ak7375_set_ctrl,
> +};
> +
> +static int ak7375_open(struct v4l2_subdev *sd, struct v4l2_subdev_fh
> +*fh) {
> + int rval;
> +
> + rval = pm_runtime_get_sync(sd->dev);
> + if (rval < 0) {
> + pm_runtime_put_noidle(sd->dev);
> + return rval;
> + }
> +
> + return 0;
> +}
> +
> +static int ak7375_close(struct v4l2_subdev *sd, struct v4l2_subdev_fh
> +*fh) {
> + pm_runtime_put(sd->dev);
> +
> + return 0;
> +}
> +
> +static const struct v4l2_subdev_internal_ops ak7375_int_ops = {
> + .open = ak7375_open,
> + .close = ak7375_close,
> +};
> +
> +static const struct v4l2_subdev_ops ak7375_ops = { };
> +
> +static void ak7375_subdev_cleanup(struct ak7375_device *ak7375_dev) {
> + v4l2_async_unregister_subdev(&ak7375_dev->sd);
> + v4l2_ctrl_handler_free(&ak7375_dev->ctrls_vcm);
> + media_entity_cleanup(&ak7375_dev->sd.entity);
> +}
> +
> +static int ak7375_init_controls(struct ak7375_device *dev_vcm) {
> + struct v4l2_ctrl_handler *hdl = &dev_vcm->ctrls_vcm;
> + const struct v4l2_ctrl_ops *ops = &ak7375_vcm_ctrl_ops;
> +
> + v4l2_ctrl_handler_init(hdl, 1);
> +
> + dev_vcm->focus = v4l2_ctrl_new_std(hdl, ops,
> V4L2_CID_FOCUS_ABSOLUTE,
> + 0, AK7375_MAX_FOCUS_POS, AK7375_FOCUS_STEPS, 0);
> +
> + if (hdl->error)
> + dev_err(dev_vcm->sd.dev, "%s fail error: 0x%x\n",
> + __func__, hdl->error);
> + dev_vcm->sd.ctrl_handler = hdl;
> + return hdl->error;
> +}
> +
> +static int ak7375_probe(struct i2c_client *client) {
> + struct ak7375_device *ak7375_dev;
> + int val;
> +
> + ak7375_dev = devm_kzalloc(&client->dev, sizeof(*ak7375_dev),
> + GFP_KERNEL);
> + if (!ak7375_dev)
> + return -ENOMEM;
> +
> + v4l2_i2c_subdev_init(&ak7375_dev->sd, client, &ak7375_ops);
> + ak7375_dev->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
> + ak7375_dev->sd.internal_ops = &ak7375_int_ops;
> + ak7375_dev->sd.entity.function = MEDIA_ENT_F_LENS;
> +
> + val = ak7375_init_controls(ak7375_dev);
> + if (val)
> + goto err_cleanup;
> +
> + val = media_entity_pads_init(&ak7375_dev->sd.entity, 0, NULL);
> + if (val < 0)
> + goto err_cleanup;
> +
> + val = v4l2_async_register_subdev(&ak7375_dev->sd);
> + if (val < 0)
> + goto err_cleanup;
> +
> + pm_runtime_set_active(&client->dev);
> + pm_runtime_enable(&client->dev);
> + pm_runtime_idle(&client->dev);
> +
> + return 0;
> +
> +err_cleanup:
> + v4l2_ctrl_handler_free(&ak7375_dev->ctrls_vcm);
> + media_entity_cleanup(&ak7375_dev->sd.entity);
> + dev_err(&client->dev, "Probe failed: %d\n", val);
> + return val;
> +}
> +
> +static int ak7375_remove(struct i2c_client *client) {
> + struct v4l2_subdev *sd = i2c_get_clientdata(client);
> + struct ak7375_device *ak7375_dev = sd_to_ak7375_vcm(sd);
> +
> + ak7375_subdev_cleanup(ak7375_dev);
> + pm_runtime_disable(&client->dev);
> + pm_runtime_set_suspended(&client->dev);
> +
> + return 0;
> +}
> +
> +/*
> + * This function sets the vcm position, so it consumes least current
> + * The lens position is gradually moved in units of AK7375_CTRL_STEPS,
> + * to make the movements smoothly.
> + */
> +static int __maybe_unused ak7375_vcm_suspend(struct device *dev) {
> +
> + struct i2c_client *client = to_i2c_client(dev);
> + struct v4l2_subdev *sd = i2c_get_clientdata(client);
> + struct ak7375_device *ak7375_dev = sd_to_ak7375_vcm(sd);
> + int ret, val;
> +
AK7375 enters stand-by mode after power-on, per data sheet.
When the driver gets probed and this PM function is called, AK7375 should
still be in stand-by mode (as active mode is set only in ak7375_vcm_resume).
Per the data sheet, the vcm should be set to "active" mode, for the magnet
to move (which uses AK7375_REG_POSITION values).
> + for (val = ak7375_dev->focus->val & ~(AK7375_CTRL_STEPS - 1);
> + val >= 0; val -= AK7375_CTRL_STEPS) {
> + ret = ak7375_i2c_write(ak7375_dev, AK7375_REG_POSITION,
> + val << 4, 2);
> + if (ret)
> + dev_err_once(dev, "%s I2C failure: %d\n",
> + __func__, ret);
> + usleep_range(AK7375_CTRL_DELAY_US,
> AK7375_CTRL_DELAY_US + 10);
> + }
> +
> + ret = ak7375_i2c_write(ak7375_dev, AK7375_REG_CONT,
> + AK7375_MODE_STANDBY, 1);
> + if (ret) {
> + dev_err(dev, "%s I2C failure: %d\n", __func__, ret);
> + return ret;
I think we should proceed with the suspend, without returning the
error code (just like how it is done for REG_POSITION writes a little
earlier), as it might not be worth preventing the system suspend for
this issue.
> + }
> + return 0;
> +}
> +
> +/*
> + * 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 AK7375_CTRL_STEPS,
> + * to make the movements smoothly.
> + */
> +static int __maybe_unused ak7375_vcm_resume(struct device *dev) {
> + struct i2c_client *client = to_i2c_client(dev);
> + struct v4l2_subdev *sd = i2c_get_clientdata(client);
> + struct ak7375_device *ak7375_dev = sd_to_ak7375_vcm(sd);
> + int ret, val;
> +
> + ret = ak7375_i2c_write(ak7375_dev, AK7375_REG_CONT,
> + AK7375_MODE_ACTIVE, 1);
> + if (ret) {
> + dev_err(dev, "%s I2C failure: %d\n", __func__, ret);
> + return ret;
> + }
> +
> + for (val = ak7375_dev->focus->val % AK7375_CTRL_STEPS;
> + val <= ak7375_dev->focus->val;
> + val += AK7375_CTRL_STEPS) {
> + ret = ak7375_i2c_write(ak7375_dev, AK7375_REG_POSITION,
> + val << 4, 2);
> + if (ret)
> + dev_err_ratelimited(dev, "%s I2C failure: %d\n",
> + __func__, ret);
> + usleep_range(AK7375_CTRL_DELAY_US,
> AK7375_CTRL_DELAY_US + 10);
> + }
> + return 0;
> +}
> +
> +static const struct of_device_id ak7375_of_table[] = {
> + { .compatible = "asahi-kasei,ak7375" },
> + { /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, ak7375_of_table);
> +
> +static const struct dev_pm_ops ak7375_pm_ops = {
> + SET_SYSTEM_SLEEP_PM_OPS(ak7375_vcm_suspend,
> ak7375_vcm_resume)
> + SET_RUNTIME_PM_OPS(ak7375_vcm_suspend, ak7375_vcm_resume,
> NULL) };
> +
> +static struct i2c_driver ak7375_i2c_driver = {
> + .driver = {
> + .name = "ak7375",
> + .pm = &ak7375_pm_ops,
> + .of_match_table = ak7375_of_table,
> + },
> + .probe_new = ak7375_probe,
> + .remove = ak7375_remove,
> +};
> +module_i2c_driver(ak7375_i2c_driver);
> +
> +MODULE_AUTHOR("Tianshu Qiu <tian.shu.qiu@xxxxxxxxx>");
> +MODULE_AUTHOR("Bingbu Cao <bingbu.cao@xxxxxxxxx>");
> +MODULE_DESCRIPTION("AK7375 VCM driver"); MODULE_LICENSE("GPL v2");
> --
> 1.9.1
