Re: [V2, 2/2] media: i2c: Add DW9768 VCM driver

Sakari Ailus
2019-09-05T08:21:34Z

Hi Dongchun,

Thanks for the update. A few comments below.

On Thu, Sep 05, 2019 at 03:21:42PM +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 DW9768 is a 10 bit DAC with 100mA output current sink capability
> from Dongwoon, designed for linear control of voice coil motor,
> and controlled via I2C serial interface.
>
> 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 | 349 +++++++++++++++++++++++++++++++++++++++++++++
> 4 files changed, 361 insertions(+)
> create mode 100644 drivers/media/i2c/dw9768.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 192a671..c5c9a0e 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -4976,6 +4976,7 @@ 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 79ce9ec..dfb665c 100644
> --- a/drivers/media/i2c/Kconfig
> +++ b/drivers/media/i2c/Kconfig
> @@ -1016,6 +1016,16 @@ 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 fd4ea86..2561239 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..66d1712
> --- /dev/null
> +++ b/drivers/media/i2c/dw9768.c
> @@ -0,0 +1,349 @@
> +// SPDX-License-Identifier: GPL-2.0
> +// Copyright (c) 2019 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_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
> +/*
> + * DW9768 separates two registers to control the VCM position.
> + * One for MSB value, another is LSB value.
> + */
> +#define DW9768_REG_MASK_MSB 0x03
> +#define DW9768_REG_MASK_LSB 0xff
> +#define DW9768_SET_POSITION_ADDR 0x03
> +
> +#define DW9768_CMD_DELAY 0xff
> +#define DW9768_CTRL_DELAY_US 5000
> +
> +#define DW9768_DAC_SHIFT 8
> +
> +/* dw9768 device structure */
> +struct dw9768 {
> + struct v4l2_ctrl_handler ctrls;
> + struct v4l2_subdev sd;
> + struct regulator *vin;
> + struct regulator *vdd;
> +};
> +
> +static inline struct dw9768 *to_dw9768_vcm(struct v4l2_ctrl *ctrl)
> +{
> + return container_of(ctrl->handler, struct dw9768, ctrls);
> +}
> +
> +static inline struct dw9768 *sd_to_dw9768_vcm(struct v4l2_subdev *subdev)
> +{
> + return container_of(subdev, struct dw9768, sd);
> +}
> +
> +struct regval_list {
> + unsigned char reg_num;
> + unsigned char value;
> +};
> +
> +static struct regval_list dw9768_init_regs[] = {
> + {0x02, 0x02},
> + {DW9768_CMD_DELAY, DW9768_CMD_DELAY},
> + {0x06, 0x41},
> + {0x07, 0x39},

These need to be documented. Please add #defines for the register addresses
and bits in the registers as needed.

The writes would better be done as function calls; the same applies to the
delays.

> + {DW9768_CMD_DELAY, DW9768_CMD_DELAY},
> +};
> +
> +static struct regval_list dw9768_release_regs[] = {
> + {0x02, 0x00},
> + {DW9768_CMD_DELAY, DW9768_CMD_DELAY},
> + {0x01, 0x00},

Same here.

> + {DW9768_CMD_DELAY, DW9768_CMD_DELAY},
> +};
> +
> +static int dw9768_write_smbus(struct dw9768 *dw9768, unsigned char reg,
> + unsigned char value)
> +{
> + struct i2c_client *client = v4l2_get_subdevdata(&dw9768->sd);
> + int ret;
> +
> + if (reg == DW9768_CMD_DELAY && value == DW9768_CMD_DELAY)
> + usleep_range(DW9768_CTRL_DELAY_US,
> + DW9768_CTRL_DELAY_US + 100);
> + else
> + ret = i2c_smbus_write_byte_data(client, reg, value);
> + return ret;
> +}
> +
> +static int dw9768_write_array(struct dw9768 *dw9768, struct regval_list *vals,
> + u32 len)
> +{
> + unsigned int i;
> + int ret;
> +
> + for (i = 0; i < len; i++) {
> + ret = dw9768_write_smbus(dw9768, vals->reg_num, vals->value);
> + if (ret < 0)
> + return ret;
> + }
> + return 0;
> +}
> +
> +static int dw9768_set_position(struct dw9768 *dw9768, u16 val)
> +{
> + struct i2c_client *client = v4l2_get_subdevdata(&dw9768->sd);
> + u8 addr[2];
> +
> + addr[0] = (val >> DW9768_DAC_SHIFT) & DW9768_REG_MASK_MSB;
> + addr[1] = val & DW9768_REG_MASK_LSB;
> +
> + return i2c_smbus_write_block_data(client, DW9768_SET_POSITION_ADDR,
> + ARRAY_SIZE(addr), addr);
> +}
> +
> +static int dw9768_release(struct dw9768 *dw9768)
> +{
> + return dw9768_write_array(dw9768, dw9768_release_regs,
> + ARRAY_SIZE(dw9768_release_regs));
> +}
> +
> +static int dw9768_init(struct dw9768 *dw9768)
> +{
> + return dw9768_write_array(dw9768, dw9768_init_regs,
> + ARRAY_SIZE(dw9768_init_regs));
> +}
> +
> +/* Power handling */
> +static int dw9768_power_off(struct dw9768 *dw9768)
> +{
> + struct i2c_client *client = v4l2_get_subdevdata(&dw9768->sd);
> + int ret;
> +
> + ret = dw9768_release(dw9768);
> + if (ret)
> + dev_err(&client->dev, "dw9768 release failed!\n");
> +
> + ret = regulator_disable(dw9768->vin);
> + if (ret)
> + return ret;

You'll need to disable the other regulator unconditionally here.

> +
> + return regulator_disable(dw9768->vdd);
> +}
> +
> +static int dw9768_power_on(struct dw9768 *dw9768)
> +{
> + int ret;
> +
> + ret = regulator_enable(dw9768->vin);
> + if (ret < 0)
> + return ret;
> +
> + ret = regulator_enable(dw9768->vdd);
> + if (ret < 0)

You'll need another label to disable only vin.

> + return ret;
> +
> + ret = dw9768_init(dw9768);
> + if (ret < 0)
> + goto fail;
> +
> + return 0;
> +
> +fail:
> + regulator_disable(dw9768->vin);
> + regulator_disable(dw9768->vdd);
> +
> + return ret;
> +}
> +
> +static int dw9768_set_ctrl(struct v4l2_ctrl *ctrl)
> +{
> + struct dw9768 *dw9768 = to_dw9768_vcm(ctrl);
> +
> + if (ctrl->id == V4L2_CID_FOCUS_ABSOLUTE)
> + return dw9768_set_position(dw9768, ctrl->val);
> +
> + return 0;
> +}
> +
> +static const struct v4l2_ctrl_ops dw9768_vcm_ctrl_ops = {
> + .s_ctrl = dw9768_set_ctrl,
> +};
> +
> +static int dw9768_open(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
> +{
> + int ret;
> +
> + ret = pm_runtime_get_sync(sd->dev);
> + if (ret < 0) {
> + pm_runtime_put_noidle(sd->dev);
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +static int dw9768_close(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
> +{
> + pm_runtime_put(sd->dev);
> +
> + return 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 *dw9768)
> +{
> + v4l2_async_unregister_subdev(&dw9768->sd);
> + v4l2_ctrl_handler_free(&dw9768->ctrls);
> + media_entity_cleanup(&dw9768->sd.entity);
> +}
> +
> +static int dw9768_init_controls(struct dw9768 *dw9768)
> +{
> + struct v4l2_ctrl_handler *hdl = &dw9768->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)
> + return hdl->error;
> +
> + dw9768->sd.ctrl_handler = hdl;
> +
> + return 0;
> +}
> +
> +static int dw9768_probe(struct i2c_client *client)
> +{
> + struct device *dev = &client->dev;
> + struct dw9768 *dw9768;
> + int ret;
> +
> + dw9768 = devm_kzalloc(dev, sizeof(*dw9768), GFP_KERNEL);
> + if (!dw9768)
> + return -ENOMEM;
> +
> + dw9768->vin = devm_regulator_get(dev, "vin");
> + if (IS_ERR(dw9768->vin)) {
> + ret = PTR_ERR(dw9768->vin);
> + if (ret != -EPROBE_DEFER)
> + dev_err(dev, "cannot get vin regulator\n");
> + return ret;
> + }
> +
> + dw9768->vdd = devm_regulator_get(dev, "vdd");
> + if (IS_ERR(dw9768->vdd)) {
> + ret = PTR_ERR(dw9768->vdd);
> + if (ret != -EPROBE_DEFER)
> + dev_err(dev, "cannot get vdd regulator\n");
> + return ret;
> + }
> +
> + v4l2_i2c_subdev_init(&dw9768->sd, client, &dw9768_ops);
> + dw9768->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
> + dw9768->sd.internal_ops = &dw9768_int_ops;
> +
> + ret = dw9768_init_controls(dw9768);
> + if (ret)
> + goto err_cleanup;
> +
> + ret = media_entity_pads_init(&dw9768->sd.entity, 0, NULL);
> + if (ret < 0)
> + goto err_cleanup;
> +
> + dw9768->sd.entity.function = MEDIA_ENT_F_LENS;
> +
> + ret = v4l2_async_register_subdev(&dw9768->sd);
> + if (ret < 0)
> + goto err_cleanup;
> +
> + pm_runtime_enable(dev);
> +
> + return 0;
> +
> +err_cleanup:
> + dw9768_subdev_cleanup(dw9768);
> + return ret;
> +}
> +
> +static int dw9768_remove(struct i2c_client *client)
> +{
> + struct v4l2_subdev *sd = i2c_get_clientdata(client);
> + struct dw9768 *dw9768 = sd_to_dw9768_vcm(sd);
> +
> + dw9768_subdev_cleanup(dw9768);
> + pm_runtime_disable(&client->dev);
> + if (!pm_runtime_status_suspended(&client->dev))
> + dw9768_power_off(dw9768);
> + pm_runtime_set_suspended(&client->dev);
> +
> + return 0;
> +}
> +
> +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 *dw9768 = sd_to_dw9768_vcm(sd);
> +
> + return dw9768_power_off(dw9768);

Please merge this function with dw9768_power_off(); same for
dw9768_vcm_resume() below.

> +}
> +
> +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 *dw9768 = sd_to_dw9768_vcm(sd);
> +
> + return dw9768_power_on(dw9768);
> +}
> +
> +static const struct i2c_device_id dw9768_id_table[] = {
> + { DW9768_NAME, 0 },
> + { },

Could you drop the I²C ID table?

> +};
> +MODULE_DEVICE_TABLE(i2c, dw9768_id_table);
> +
> +static const struct of_device_id dw9768_of_table[] = {
> + { .compatible = "dongwoon,dw9768" },
> + { },
> +};
> +MODULE_DEVICE_TABLE(of, dw9768_of_table);
> +
> +static const struct dev_pm_ops dw9768_pm_ops = {
> + SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
> + pm_runtime_force_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");

--
Kind regards,

Sakari Ailus
sakari.ailus@linux.intel.com