RESEND[PATCH v6 0/2] DW9807 DT binding and driver patches

RESEND[PATCH v6 0/2] DW9807 DT binding and driver patches

[Andy Yeh]

Hi Sakari and Tomasz,

The two patches are the DT binding and driver for DW9807 VCM controller.

Alan Chiang (2):
  media: dw9807: Add dw9807 vcm driver
  media: dt-bindings: Add bindings for Dongwoon DW9807 voice coil

 .../bindings/media/i2c/dongwoon,dw9807.txt         |   9 +
 MAINTAINERS                                        |   7 +
 drivers/media/i2c/Kconfig                          |  10 +
 drivers/media/i2c/Makefile                         |   1 +
 drivers/media/i2c/dw9807.c                         | 320 +++++++++++++++++++++
 5 files changed, 347 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/media/i2c/dongwoon,dw9807.txt
 create mode 100644 drivers/media/i2c/dw9807.c

-- 
2.7.4

RESEND[PATCH v6 1/2] media: dt-bindings: Add bindings for Dongwoon DW9807 voice coil

[Andy Yeh]

From: Alan Chiang <alanx.chiang@intel.com>

Dongwoon DW9807 is a voice coil lens driver.

Signed-off-by: Andy Yeh <andy.yeh@intel.com>
---
 Documentation/devicetree/bindings/media/i2c/dongwoon,dw9807.txt | 9 +++++++++
 1 file changed, 9 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/media/i2c/dongwoon,dw9807.txt

diff --git a/Documentation/devicetree/bindings/media/i2c/dongwoon,dw9807.txt b/Documentation/devicetree/bindings/media/i2c/dongwoon,dw9807.txt
new file mode 100644
index 0000000..0a1a860
--- /dev/null
+++ b/Documentation/devicetree/bindings/media/i2c/dongwoon,dw9807.txt
@@ -0,0 +1,9 @@
+Dongwoon Anatech DW9807 voice coil lens driver
+
+DW9807 is a 10-bit DAC with current sink capability. It is intended for
+controlling voice coil lenses.
+
+Mandatory properties:
+
+- compatible: "dongwoon,dw9807"
+- reg: I2C slave address
-- 
2.7.4

RESEND[PATCH v6 2/2] media: dw9807: Add dw9807 vcm driver

[Andy Yeh]

From: Alan Chiang <alanx.chiang@intel.com>

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

This driver creates a V4L2 subdevice and
provides control to set the desired focus.

Signed-off-by: Andy Yeh <andy.yeh@intel.com>
---
since v1:
- changed author.
since v2:
- addressed outstanding comments.
- enabled sequential write to update 2 registers in a single transaction.
since v3:
- addressed comments for v3.
- Remove redundant codes and declare some variables as constant variable.
- separate DT binding to another patch
sicne v4:
- sent patchset included DT binding with cover page

 MAINTAINERS                |   7 +
 drivers/media/i2c/Kconfig  |  10 ++
 drivers/media/i2c/Makefile |   1 +
 drivers/media/i2c/dw9807.c | 320 +++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 338 insertions(+)
 create mode 100644 drivers/media/i2c/dw9807.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 845fc25..a339bb5 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -4385,6 +4385,13 @@ T:	git git://linuxtv.org/media_tree.git
 S:	Maintained
 F:	drivers/media/i2c/dw9714.c
 
+DONGWOON DW9807 LENS VOICE COIL DRIVER
+M:	Sakari Ailus <sakari.ailus@linux.intel.com>
+L:	linux-media@vger.kernel.org
+T:	git git://linuxtv.org/media_tree.git
+S:	Maintained
+F:	drivers/media/i2c/dw9807.c
+
 DOUBLETALK DRIVER
 M:	"James R. Van Zandt" <jrv@vanzandt.mv.com>
 L:	blinux-list@redhat.com
diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
index cb5d7ff..fd01842 100644
--- a/drivers/media/i2c/Kconfig
+++ b/drivers/media/i2c/Kconfig
@@ -325,6 +325,16 @@ config VIDEO_DW9714
 	  capability. This is designed for linear control of
 	  voice coil motors, controlled via I2C serial interface.
 
+config VIDEO_DW9807
+	tristate "DW9807 lens voice coil support"
+	depends on I2C && VIDEO_V4L2 && MEDIA_CONTROLLER
+	depends on VIDEO_V4L2_SUBDEV_API
+	---help---
+	  This is a driver for the DW9807 camera lens voice coil.
+	  DW9807 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_SAA7110
 	tristate "Philips SAA7110 video decoder"
 	depends on VIDEO_V4L2 && I2C
diff --git a/drivers/media/i2c/Makefile b/drivers/media/i2c/Makefile
index 548a9ef..1b62639 100644
--- a/drivers/media/i2c/Makefile
+++ b/drivers/media/i2c/Makefile
@@ -23,6 +23,7 @@ obj-$(CONFIG_VIDEO_SAA7185) += saa7185.o
 obj-$(CONFIG_VIDEO_SAA6752HS) += saa6752hs.o
 obj-$(CONFIG_VIDEO_AD5820)  += ad5820.o
 obj-$(CONFIG_VIDEO_DW9714)  += dw9714.o
+obj-$(CONFIG_VIDEO_DW9807)  += dw9807.o
 obj-$(CONFIG_VIDEO_ADV7170) += adv7170.o
 obj-$(CONFIG_VIDEO_ADV7175) += adv7175.o
 obj-$(CONFIG_VIDEO_ADV7180) += adv7180.o
diff --git a/drivers/media/i2c/dw9807.c b/drivers/media/i2c/dw9807.c
new file mode 100644
index 0000000..95626e9
--- /dev/null
+++ b/drivers/media/i2c/dw9807.c
@@ -0,0 +1,320 @@
+// Copyright (C) 2018 Intel Corporation
+// SPDX-License-Identifier: GPL-2.0
+
+#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 DW9807_NAME		"dw9807"
+#define DW9807_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 DW9807_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 DW9807_CTRL_STEPS	16
+#define DW9807_CTRL_DELAY_US	1000
+
+#define DW9807_CTL_ADDR		0x02
+/*
+ * DW9807 separates two registers to control the VCM position.
+ * One for MSB value, another is LSB value.
+ */
+#define DW9807_MSB_ADDR		0x03
+#define DW9807_LSB_ADDR		0x04
+#define DW9807_STATUS_ADDR	0x05
+#define DW9807_MODE_ADDR	0x06
+#define DW9807_RESONANCE_ADDR	0x07
+
+#define MAX_RETRY		10
+
+struct dw9807_device {
+	struct v4l2_ctrl_handler ctrls_vcm;
+	struct v4l2_subdev sd;
+	u16 current_val;
+};
+
+static inline struct dw9807_device *sd_to_dw9807_vcm(struct v4l2_subdev *subdev)
+{
+	return container_of(subdev, struct dw9807_device, sd);
+}
+
+static int dw9807_i2c_check(struct i2c_client *client)
+{
+	const char status_addr = DW9807_STATUS_ADDR;
+	char status_result = 0x1;
+	int ret;
+
+	ret = i2c_master_send(client, (const char *)&status_addr, sizeof(status_addr));
+	if (ret != sizeof(status_addr)) {
+		dev_err(&client->dev, "I2C write STATUS address fail ret = %d\n",
+			ret);
+		return -EIO;
+	}
+
+	ret = i2c_master_recv(client, (char *)&status_result, sizeof(status_result));
+	if (ret != sizeof(status_result)) {
+		dev_err(&client->dev, "I2C read STATUS value fail ret=%d\n",
+			ret);
+		return -EIO;
+	}
+
+	return status_result;
+}
+
+static int dw9807_set_dac(struct i2c_client *client, u16 data)
+{
+	const char tx_data[3] = {
+		DW9807_MSB_ADDR, ((data >> 8) & 0x03), (data & 0xFF) };
+	int ret, retry = 0;
+
+	/*
+	 * According to the datasheet, need to check the bus status before we
+	 * write VCM position. This ensure that we really write the value
+	 * into the register
+	 */
+	while (dw9807_i2c_check(client) != 0) {
+		if (MAX_RETRY == ++retry) {
+			dev_err(&client->dev, "Cannot do the write operation because VCM is busy\n");
+			return -EIO;
+		}
+		usleep_range(DW9807_CTRL_DELAY_US, DW9807_CTRL_DELAY_US + 10);
+	}
+
+	/* Write VCM position to registers */
+	ret = i2c_master_send(client, tx_data, sizeof(tx_data));
+	if (ret != sizeof(tx_data)) {
+		dev_err(&client->dev, "I2C write MSB fail\n");
+		return -EIO;
+	}
+
+	return 0;
+}
+
+static int dw9807_set_ctrl(struct v4l2_ctrl *ctrl)
+{
+	struct dw9807_device *dev_vcm = container_of(ctrl->handler, struct dw9807_device, ctrls_vcm);
+
+	if (ctrl->id == V4L2_CID_FOCUS_ABSOLUTE) {
+		struct i2c_client *client = v4l2_get_subdevdata(&dev_vcm->sd);
+
+		dev_vcm->current_val = ctrl->val;
+		return dw9807_set_dac(client, ctrl->val);
+	}
+
+	return -EINVAL;
+}
+
+static const struct v4l2_ctrl_ops dw9807_vcm_ctrl_ops = {
+	.s_ctrl = dw9807_set_ctrl,
+};
+
+static int dw9807_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 dw9807_close(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
+{
+	pm_runtime_put(sd->dev);
+
+	return 0;
+}
+
+static const struct v4l2_subdev_internal_ops dw9807_int_ops = {
+	.open = dw9807_open,
+	.close = dw9807_close,
+};
+
+static const struct v4l2_subdev_ops dw9807_ops = { };
+
+static void dw9807_subdev_cleanup(struct dw9807_device *dw9807_dev)
+{
+	v4l2_async_unregister_subdev(&dw9807_dev->sd);
+	v4l2_ctrl_handler_free(&dw9807_dev->ctrls_vcm);
+	media_entity_cleanup(&dw9807_dev->sd.entity);
+}
+
+static int dw9807_init_controls(struct dw9807_device *dev_vcm)
+{
+	struct v4l2_ctrl_handler *hdl = &dev_vcm->ctrls_vcm;
+	const struct v4l2_ctrl_ops *ops = &dw9807_vcm_ctrl_ops;
+	struct i2c_client *client = v4l2_get_subdevdata(&dev_vcm->sd);
+
+	v4l2_ctrl_handler_init(hdl, 1);
+
+	v4l2_ctrl_new_std(hdl, ops, V4L2_CID_FOCUS_ABSOLUTE,
+			  0, DW9807_MAX_FOCUS_POS, DW9807_FOCUS_STEPS, 0);
+
+	dev_vcm->sd.ctrl_handler = hdl;
+	if (hdl->error) {
+		dev_err(&client->dev, "%s fail error: 0x%x\n",
+			__func__, hdl->error);
+		return hdl->error;
+	}
+
+	return 0;
+}
+
+static int dw9807_probe(struct i2c_client *client)
+{
+	struct dw9807_device *dw9807_dev;
+	int rval;
+
+	dw9807_dev = devm_kzalloc(&client->dev, sizeof(*dw9807_dev),
+				  GFP_KERNEL);
+	if (dw9807_dev == NULL)
+		return -ENOMEM;
+
+	v4l2_i2c_subdev_init(&dw9807_dev->sd, client, &dw9807_ops);
+	dw9807_dev->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
+	dw9807_dev->sd.internal_ops = &dw9807_int_ops;
+
+	rval = dw9807_init_controls(dw9807_dev);
+	if (rval)
+		goto err_cleanup;
+
+	rval = media_entity_pads_init(&dw9807_dev->sd.entity, 0, NULL);
+	if (rval < 0)
+		goto err_cleanup;
+
+	dw9807_dev->sd.entity.function = MEDIA_ENT_F_LENS;
+
+	rval = v4l2_async_register_subdev(&dw9807_dev->sd);
+	if (rval < 0)
+		goto err_cleanup;
+
+	pm_runtime_set_active(&client->dev);
+	pm_runtime_enable(&client->dev);
+	pm_runtime_idle(&client->dev);
+
+	return 0;
+
+err_cleanup:
+	dw9807_subdev_cleanup(dw9807_dev);
+	return rval;
+}
+
+static int dw9807_remove(struct i2c_client *client)
+{
+	struct v4l2_subdev *sd = i2c_get_clientdata(client);
+	struct dw9807_device *dw9807_dev = sd_to_dw9807_vcm(sd);
+
+	pm_runtime_disable(&client->dev);
+	pm_runtime_set_suspended(&client->dev);
+
+	dw9807_subdev_cleanup(dw9807_dev);
+
+	return 0;
+}
+
+/*
+ * This function sets the vcm position, so it consumes least current
+ * The lens position is gradually moved in units of DW9807_CTRL_STEPS,
+ * to make the movements smoothly.
+ */
+static int __maybe_unused dw9807_vcm_suspend(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct v4l2_subdev *sd = i2c_get_clientdata(client);
+	struct dw9807_device *dw9807_dev = sd_to_dw9807_vcm(sd);
+	const char tx_data[2] = { DW9807_CTL_ADDR, 0x01 };
+	int ret, val;
+
+	for (val = dw9807_dev->current_val & ~(DW9807_CTRL_STEPS - 1);
+	     val >= 0; val -= DW9807_CTRL_STEPS) {
+		ret = dw9807_set_dac(client, val);
+		if (ret)
+			dev_err_once(dev, "%s I2C failure: %d", __func__, ret);
+		usleep_range(DW9807_CTRL_DELAY_US, DW9807_CTRL_DELAY_US + 10);
+	}
+
+	/* Power down */
+	ret = i2c_master_send(client, tx_data, sizeof(tx_data));
+
+	if (ret != sizeof(tx_data)) {
+		dev_err(&client->dev, "I2C write CTL fail\n");
+		return -EIO;
+	}
+
+	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 DW9807_CTRL_STEPS,
+ * to make the movements smoothly.
+ */
+static int  __maybe_unused dw9807_vcm_resume(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct v4l2_subdev *sd = i2c_get_clientdata(client);
+	struct dw9807_device *dw9807_dev = sd_to_dw9807_vcm(sd);
+	const char tx_data[2] = { DW9807_CTL_ADDR, 0x00 };
+	int ret, val;
+
+	/* Power on */
+	ret = i2c_master_send(client, tx_data, sizeof(tx_data));
+	if (ret != sizeof(tx_data)) {
+		dev_err(&client->dev, "I2C write CTL fail\n");
+		return -EIO;
+	}
+
+	for (val = dw9807_dev->current_val % DW9807_CTRL_STEPS;
+	     val < dw9807_dev->current_val + DW9807_CTRL_STEPS - 1;
+	     val += DW9807_CTRL_STEPS) {
+		ret = dw9807_set_dac(client, val);
+		if (ret)
+			dev_err_ratelimited(dev, "%s I2C failure: %d",
+						__func__, ret);
+		usleep_range(DW9807_CTRL_DELAY_US, DW9807_CTRL_DELAY_US + 10);
+	}
+
+	return 0;
+}
+
+static const struct of_device_id dw9807_of_table[] = {
+	{ .compatible = "dongwoon,dw9807" },
+	{ { 0 } }
+};
+MODULE_DEVICE_TABLE(of, dw9807_of_table);
+
+static const struct dev_pm_ops dw9807_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(dw9807_vcm_suspend, dw9807_vcm_resume)
+	SET_RUNTIME_PM_OPS(dw9807_vcm_suspend, dw9807_vcm_resume, NULL)
+};
+
+static struct i2c_driver dw9807_i2c_driver = {
+	.driver = {
+		.name = DW9807_NAME,
+		.pm = &dw9807_pm_ops,
+		.of_match_table = dw9807_of_table,
+	},
+	.probe_new = dw9807_probe,
+	.remove = dw9807_remove,
+};
+
+module_i2c_driver(dw9807_i2c_driver);
+
+MODULE_AUTHOR("Chiang, Alan <alanx.chiang@intel.com>");
+MODULE_DESCRIPTION("DW9807 VCM driver");
+MODULE_LICENSE("GPL v2");
-- 
2.7.4

Re: RESEND[PATCH v6 2/2] media: dw9807: Add dw9807 vcm driver

[jacopo mondi]

[-- Attachment #1: Type: text/plain, Size: 13778 bytes --]

Hi Andy,
   a few comments on you patch below...

On Sat, Mar 17, 2018 at 01:05:26AM +0800, Andy Yeh wrote:
> From: Alan Chiang <alanx.chiang@intel.com>
>
> DW9807 is a 10 bit DAC from Dongwoon, designed for linear
> control of voice coil motor.
>
> This driver creates a V4L2 subdevice and
> provides control to set the desired focus.
>
> Signed-off-by: Andy Yeh <andy.yeh@intel.com>
> ---
> since v1:
> - changed author.
> since v2:
> - addressed outstanding comments.
> - enabled sequential write to update 2 registers in a single transaction.
> since v3:
> - addressed comments for v3.
> - Remove redundant codes and declare some variables as constant variable.
> - separate DT binding to another patch
> sicne v4:
> - sent patchset included DT binding with cover page
>
>  MAINTAINERS                |   7 +
>  drivers/media/i2c/Kconfig  |  10 ++
>  drivers/media/i2c/Makefile |   1 +
>  drivers/media/i2c/dw9807.c | 320 +++++++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 338 insertions(+)
>  create mode 100644 drivers/media/i2c/dw9807.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 845fc25..a339bb5 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -4385,6 +4385,13 @@ T:	git git://linuxtv.org/media_tree.git
>  S:	Maintained
>  F:	drivers/media/i2c/dw9714.c
>
> +DONGWOON DW9807 LENS VOICE COIL DRIVER
> +M:	Sakari Ailus <sakari.ailus@linux.intel.com>
> +L:	linux-media@vger.kernel.org
> +T:	git git://linuxtv.org/media_tree.git
> +S:	Maintained
> +F:	drivers/media/i2c/dw9807.c
> +
>  DOUBLETALK DRIVER
>  M:	"James R. Van Zandt" <jrv@vanzandt.mv.com>
>  L:	blinux-list@redhat.com
> diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
> index cb5d7ff..fd01842 100644
> --- a/drivers/media/i2c/Kconfig
> +++ b/drivers/media/i2c/Kconfig
> @@ -325,6 +325,16 @@ config VIDEO_DW9714
>  	  capability. This is designed for linear control of
>  	  voice coil motors, controlled via I2C serial interface.
>
> +config VIDEO_DW9807
> +	tristate "DW9807 lens voice coil support"
> +	depends on I2C && VIDEO_V4L2 && MEDIA_CONTROLLER
> +	depends on VIDEO_V4L2_SUBDEV_API
> +	---help---
> +	  This is a driver for the DW9807 camera lens voice coil.
> +	  DW9807 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_SAA7110
>  	tristate "Philips SAA7110 video decoder"
>  	depends on VIDEO_V4L2 && I2C
> diff --git a/drivers/media/i2c/Makefile b/drivers/media/i2c/Makefile
> index 548a9ef..1b62639 100644
> --- a/drivers/media/i2c/Makefile
> +++ b/drivers/media/i2c/Makefile
> @@ -23,6 +23,7 @@ obj-$(CONFIG_VIDEO_SAA7185) += saa7185.o
>  obj-$(CONFIG_VIDEO_SAA6752HS) += saa6752hs.o
>  obj-$(CONFIG_VIDEO_AD5820)  += ad5820.o
>  obj-$(CONFIG_VIDEO_DW9714)  += dw9714.o
> +obj-$(CONFIG_VIDEO_DW9807)  += dw9807.o
>  obj-$(CONFIG_VIDEO_ADV7170) += adv7170.o
>  obj-$(CONFIG_VIDEO_ADV7175) += adv7175.o
>  obj-$(CONFIG_VIDEO_ADV7180) += adv7180.o
> diff --git a/drivers/media/i2c/dw9807.c b/drivers/media/i2c/dw9807.c
> new file mode 100644
> index 0000000..95626e9
> --- /dev/null
> +++ b/drivers/media/i2c/dw9807.c
> @@ -0,0 +1,320 @@
> +// Copyright (C) 2018 Intel Corporation
> +// SPDX-License-Identifier: GPL-2.0
> +

Nit: my understanding is that the SPDX identifier goes first

> +#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 DW9807_NAME		"dw9807"
> +#define DW9807_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

Please end comments with a full stop, here and in the rest of the
driver.

> + */
> +#define DW9807_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 DW9807_CTRL_STEPS	16
> +#define DW9807_CTRL_DELAY_US	1000
> +
> +#define DW9807_CTL_ADDR		0x02
> +/*
> + * DW9807 separates two registers to control the VCM position.
> + * One for MSB value, another is LSB value.
> + */
> +#define DW9807_MSB_ADDR		0x03
> +#define DW9807_LSB_ADDR		0x04
> +#define DW9807_STATUS_ADDR	0x05
> +#define DW9807_MODE_ADDR	0x06
> +#define DW9807_RESONANCE_ADDR	0x07
> +
> +#define MAX_RETRY		10
> +
> +struct dw9807_device {
> +	struct v4l2_ctrl_handler ctrls_vcm;
> +	struct v4l2_subdev sd;
> +	u16 current_val;
> +};
> +
> +static inline struct dw9807_device *sd_to_dw9807_vcm(struct v4l2_subdev *subdev)
> +{
> +	return container_of(subdev, struct dw9807_device, sd);
> +}
> +
> +static int dw9807_i2c_check(struct i2c_client *client)
> +{
> +	const char status_addr = DW9807_STATUS_ADDR;
> +	char status_result = 0x1;

Do you need to intialize this?

> +	int ret;
> +
> +	ret = i2c_master_send(client, (const char *)&status_addr, sizeof(status_addr));
> +	if (ret != sizeof(status_addr)) {

I think ret is either < 0 or the buffer length byte count.

i2c_master_send() calls i2c_transfer_buffer_flags that uses i2c_transfer().
i2c_transfer returns either an error code, or the number of i2c messages transfered.

i2c_master_send(client, buf, count):
        return i2c_transfer_buffer_flags(client, buf, count, 0):
                ret = i2c_transfer(adapter, buf, count);
                return (ret == 1) ? count : ret;





> +		dev_err(&client->dev, "I2C write STATUS address fail ret = %d\n",
> +			ret);
> +		return -EIO;

please consider returning ret to propagate the i2c error

> +	}
> +
> +	ret = i2c_master_recv(client, (char *)&status_result, sizeof(status_result));
> +	if (ret != sizeof(status_result)) {
> +		dev_err(&client->dev, "I2C read STATUS value fail ret=%d\n",
> +			ret);
> +		return -EIO;
> +	}

same here

> +
> +	return status_result;
> +}
> +
> +static int dw9807_set_dac(struct i2c_client *client, u16 data)
> +{
> +	const char tx_data[3] = {
> +		DW9807_MSB_ADDR, ((data >> 8) & 0x03), (data & 0xFF) };

lowercase for hex (0xff).
Also, this is not a general rule, but, could you consider closing the
brace on next line?

> +	int ret, retry = 0;
> +
> +	/*
> +	 * According to the datasheet, need to check the bus status before we
> +	 * write VCM position. This ensure that we really write the value
> +	 * into the register
> +	 */
> +	while (dw9807_i2c_check(client) != 0) {

Up to you, but with this check, you are ignoring i2c errors

> +		if (MAX_RETRY == ++retry) {
> +			dev_err(&client->dev, "Cannot do the write operation because VCM is busy\n");
> +			return -EIO;
> +		}
> +		usleep_range(DW9807_CTRL_DELAY_US, DW9807_CTRL_DELAY_US + 10);
> +	}
> +
> +	/* Write VCM position to registers */
> +	ret = i2c_master_send(client, tx_data, sizeof(tx_data));
> +	if (ret != sizeof(tx_data)) {
> +		dev_err(&client->dev, "I2C write MSB fail\n");

Same as above. Check for < 0 and please printout the error code in the
error message (and consider propagating to the caller).

> +		return -EIO;
> +	}
> +
> +	return 0;
> +}
> +
> +static int dw9807_set_ctrl(struct v4l2_ctrl *ctrl)
> +{
> +	struct dw9807_device *dev_vcm = container_of(ctrl->handler, struct dw9807_device, ctrls_vcm);

This seems clearly longer than 80 cols. Have you run checkpatch on
this?

> +
> +	if (ctrl->id == V4L2_CID_FOCUS_ABSOLUTE) {
> +		struct i2c_client *client = v4l2_get_subdevdata(&dev_vcm->sd);
> +
> +		dev_vcm->current_val = ctrl->val;
> +		return dw9807_set_dac(client, ctrl->val);
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +static const struct v4l2_ctrl_ops dw9807_vcm_ctrl_ops = {
> +	.s_ctrl = dw9807_set_ctrl,
> +};
> +
> +static int dw9807_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);

If you fail to get pm context, no need to put it back (I presume)

> +		return rval;
> +	}
> +
> +	return 0;
> +}
> +
> +static int dw9807_close(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
> +{
> +	pm_runtime_put(sd->dev);
> +
> +	return 0;
> +}
> +
> +static const struct v4l2_subdev_internal_ops dw9807_int_ops = {
> +	.open = dw9807_open,
> +	.close = dw9807_close,
> +};
> +
> +static const struct v4l2_subdev_ops dw9807_ops = { };
> +
> +static void dw9807_subdev_cleanup(struct dw9807_device *dw9807_dev)
> +{
> +	v4l2_async_unregister_subdev(&dw9807_dev->sd);
> +	v4l2_ctrl_handler_free(&dw9807_dev->ctrls_vcm);
> +	media_entity_cleanup(&dw9807_dev->sd.entity);
> +}
> +
> +static int dw9807_init_controls(struct dw9807_device *dev_vcm)
> +{
> +	struct v4l2_ctrl_handler *hdl = &dev_vcm->ctrls_vcm;
> +	const struct v4l2_ctrl_ops *ops = &dw9807_vcm_ctrl_ops;
> +	struct i2c_client *client = v4l2_get_subdevdata(&dev_vcm->sd);
> +
> +	v4l2_ctrl_handler_init(hdl, 1);
> +
> +	v4l2_ctrl_new_std(hdl, ops, V4L2_CID_FOCUS_ABSOLUTE,
> +			  0, DW9807_MAX_FOCUS_POS, DW9807_FOCUS_STEPS, 0);
> +
> +	dev_vcm->sd.ctrl_handler = hdl;
> +	if (hdl->error) {
> +		dev_err(&client->dev, "%s fail error: 0x%x\n",
> +			__func__, hdl->error);
> +		return hdl->error;
> +	}
> +
> +	return 0;
> +}
> +
> +static int dw9807_probe(struct i2c_client *client)
> +{
> +	struct dw9807_device *dw9807_dev;
> +	int rval;
> +
> +	dw9807_dev = devm_kzalloc(&client->dev, sizeof(*dw9807_dev),
> +				  GFP_KERNEL);
> +	if (dw9807_dev == NULL)

if (!dw9807) or checkpatch complains

> +		return -ENOMEM;
> +
> +	v4l2_i2c_subdev_init(&dw9807_dev->sd, client, &dw9807_ops);
> +	dw9807_dev->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
> +	dw9807_dev->sd.internal_ops = &dw9807_int_ops;
> +
> +	rval = dw9807_init_controls(dw9807_dev);
> +	if (rval)
> +		goto err_cleanup;
> +
> +	rval = media_entity_pads_init(&dw9807_dev->sd.entity, 0, NULL);
> +	if (rval < 0)
> +		goto err_cleanup;
> +
> +	dw9807_dev->sd.entity.function = MEDIA_ENT_F_LENS;
> +
> +	rval = v4l2_async_register_subdev(&dw9807_dev->sd);
> +	if (rval < 0)
> +		goto err_cleanup;
> +
> +	pm_runtime_set_active(&client->dev);
> +	pm_runtime_enable(&client->dev);
> +	pm_runtime_idle(&client->dev);
> +
> +	return 0;
> +
> +err_cleanup:
> +	dw9807_subdev_cleanup(dw9807_dev);

empty line before return maybe?

> +	return rval;
> +}
> +
> +static int dw9807_remove(struct i2c_client *client)
> +{
> +	struct v4l2_subdev *sd = i2c_get_clientdata(client);
> +	struct dw9807_device *dw9807_dev = sd_to_dw9807_vcm(sd);
> +
> +	pm_runtime_disable(&client->dev);
> +	pm_runtime_set_suspended(&client->dev);
> +
> +	dw9807_subdev_cleanup(dw9807_dev);
> +
> +	return 0;
> +}
> +
> +/*
> + * This function sets the vcm position, so it consumes least current
> + * The lens position is gradually moved in units of DW9807_CTRL_STEPS,
> + * to make the movements smoothly.
> + */
> +static int __maybe_unused dw9807_vcm_suspend(struct device *dev)
> +{
> +	struct i2c_client *client = to_i2c_client(dev);
> +	struct v4l2_subdev *sd = i2c_get_clientdata(client);
> +	struct dw9807_device *dw9807_dev = sd_to_dw9807_vcm(sd);
> +	const char tx_data[2] = { DW9807_CTL_ADDR, 0x01 };
> +	int ret, val;
> +
> +	for (val = dw9807_dev->current_val & ~(DW9807_CTRL_STEPS - 1);
> +	     val >= 0; val -= DW9807_CTRL_STEPS) {
> +		ret = dw9807_set_dac(client, val);
> +		if (ret)
> +			dev_err_once(dev, "%s I2C failure: %d", __func__, ret);
> +		usleep_range(DW9807_CTRL_DELAY_US, DW9807_CTRL_DELAY_US + 10);
> +	}
> +
> +	/* Power down */
> +	ret = i2c_master_send(client, tx_data, sizeof(tx_data));
> +
> +	if (ret != sizeof(tx_data)) {
> +		dev_err(&client->dev, "I2C write CTL fail\n");
> +		return -EIO;
> +	}
> +
> +	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 DW9807_CTRL_STEPS,
> + * to make the movements smoothly.
> + */
> +static int  __maybe_unused dw9807_vcm_resume(struct device *dev)
> +{
> +	struct i2c_client *client = to_i2c_client(dev);
> +	struct v4l2_subdev *sd = i2c_get_clientdata(client);
> +	struct dw9807_device *dw9807_dev = sd_to_dw9807_vcm(sd);
> +	const char tx_data[2] = { DW9807_CTL_ADDR, 0x00 };
> +	int ret, val;
> +
> +	/* Power on */
> +	ret = i2c_master_send(client, tx_data, sizeof(tx_data));
> +	if (ret != sizeof(tx_data)) {
> +		dev_err(&client->dev, "I2C write CTL fail\n");
> +		return -EIO;
> +	}
> +
> +	for (val = dw9807_dev->current_val % DW9807_CTRL_STEPS;
> +	     val < dw9807_dev->current_val + DW9807_CTRL_STEPS - 1;
> +	     val += DW9807_CTRL_STEPS) {
> +		ret = dw9807_set_dac(client, val);
> +		if (ret)
> +			dev_err_ratelimited(dev, "%s I2C failure: %d",
> +						__func__, ret);
> +		usleep_range(DW9807_CTRL_DELAY_US, DW9807_CTRL_DELAY_US + 10);
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id dw9807_of_table[] = {
> +	{ .compatible = "dongwoon,dw9807" },
> +	{ { 0 } }

{ } is enough.

> +};
> +MODULE_DEVICE_TABLE(of, dw9807_of_table);
> +
> +static const struct dev_pm_ops dw9807_pm_ops = {
> +	SET_SYSTEM_SLEEP_PM_OPS(dw9807_vcm_suspend, dw9807_vcm_resume)
> +	SET_RUNTIME_PM_OPS(dw9807_vcm_suspend, dw9807_vcm_resume, NULL)
> +};
> +
> +static struct i2c_driver dw9807_i2c_driver = {
> +	.driver = {
> +		.name = DW9807_NAME,

That DW9807_NAME define is used only here.

Thanks
   j


> +		.pm = &dw9807_pm_ops,
> +		.of_match_table = dw9807_of_table,
> +	},
> +	.probe_new = dw9807_probe,
> +	.remove = dw9807_remove,
> +};
> +
> +module_i2c_driver(dw9807_i2c_driver);
> +
> +MODULE_AUTHOR("Chiang, Alan <alanx.chiang@intel.com>");
> +MODULE_DESCRIPTION("DW9807 VCM driver");
> +MODULE_LICENSE("GPL v2");
> --
> 2.7.4
>

[-- Attachment #2: signature.asc --]
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Re: RESEND[PATCH v6 2/2] media: dw9807: Add dw9807 vcm driver

[Sakari Ailus]

Hi Jacopo,

On Tue, Mar 20, 2018 at 11:28:17AM +0100, jacopo mondi wrote:
...
> > +static int dw9807_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);
> 
> If you fail to get pm context, no need to put it back (I presume)

pm_runtime_get() must be followed by pm_runtime_put() whether the former
succeeds or not.

...

> > +static const struct of_device_id dw9807_of_table[] = {
> > +	{ .compatible = "dongwoon,dw9807" },
> > +	{ { 0 } }
> 
> { } is enough.

{ } is GCC specific while { { 0 } } isn't.

-- 
Kind regards,

Sakari Ailus
sakari.ailus@linux.intel.com

RE: RESEND[PATCH v6 2/2] media: dw9807: Add dw9807 vcm driver

[Yeh, Andy]

Thanks for the comments. A quick question first. For the reset we need some time to address.

-----Original Message-----
From: jacopo mondi [mailto:jacopo@jmondi.org]
Sent: Tuesday, March 20, 2018 6:28 PM
To: Yeh, Andy <andy.yeh@intel.com>
Cc: linux-media@vger.kernel.org; sakari.ailus@linux.intel.com; devicetree@vger.kernel.org; Chiang, AlanX <alanx.chiang@intel.com>
Subject: Re: RESEND[PATCH v6 2/2] media: dw9807: Add dw9807 vcm driver

Hi Andy,
   a few comments on you patch below...

On Sat, Mar 17, 2018 at 01:05:26AM +0800, Andy Yeh wrote:
> From: Alan Chiang <alanx.chiang@intel.com> 
> a/drivers/media/i2c/dw9807.c b/drivers/media/i2c/dw9807.c new file 
> mode 100644 index 0000000..95626e9
> --- /dev/null
> +++ b/drivers/media/i2c/dw9807.c
> @@ -0,0 +1,320 @@
> +// Copyright (C) 2018 Intel Corporation // SPDX-License-Identifier: 
> +GPL-2.0
> +

Nit: my understanding is that the SPDX identifier goes first

https://lwn.net/Articles/739183/

I checked this site. And it says Copyright should be before SPDX identifier.
========== file01.c ==========
// Copyright (c) 2012-2016 Joe Random Hacker // SPDX-License-Identifier: BSD-2-Clause ...
========== file02.c ==========
// Copyright (c) 2017 Jon Severinsson
// SPDX-License-Identifier: BSD-2-Clause ...
========== file03.c ==========
// Copyright (c) 2008 The NetBSD Foundation, Inc.
// SPDX-License-Identifier: BSD-2-Clause-NetBSD

> +#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 DW9807_NAME		"dw9807"
> +#define DW9807_MAX_FOCUS_POS	1023
>

Re: RESEND[PATCH v6 2/2] media: dw9807: Add dw9807 vcm driver

[sakari.ailus]

Hi Andy,

On Wed, Mar 21, 2018 at 03:58:42PM +0000, Yeh, Andy wrote:
> Thanks for the comments. A quick question first. For the reset we need some time to address.
> 
> -----Original Message-----
> From: jacopo mondi [mailto:jacopo@jmondi.org]
> Sent: Tuesday, March 20, 2018 6:28 PM
> To: Yeh, Andy <andy.yeh@intel.com>
> Cc: linux-media@vger.kernel.org; sakari.ailus@linux.intel.com; devicetree@vger.kernel.org; Chiang, AlanX <alanx.chiang@intel.com>
> Subject: Re: RESEND[PATCH v6 2/2] media: dw9807: Add dw9807 vcm driver
> 
> Hi Andy,
>    a few comments on you patch below...
> 
> On Sat, Mar 17, 2018 at 01:05:26AM +0800, Andy Yeh wrote:
> > From: Alan Chiang <alanx.chiang@intel.com> 
> > a/drivers/media/i2c/dw9807.c b/drivers/media/i2c/dw9807.c new file 
> > mode 100644 index 0000000..95626e9
> > --- /dev/null
> > +++ b/drivers/media/i2c/dw9807.c
> > @@ -0,0 +1,320 @@
> > +// Copyright (C) 2018 Intel Corporation // SPDX-License-Identifier: 
> > +GPL-2.0
> > +
> 
> Nit: my understanding is that the SPDX identifier goes first
> 
> https://lwn.net/Articles/739183/
> 
> I checked this site. And it says Copyright should be before SPDX identifier.
> ========== file01.c ==========
> // Copyright (c) 2012-2016 Joe Random Hacker // SPDX-License-Identifier: BSD-2-Clause ...
> ========== file02.c ==========
> // Copyright (c) 2017 Jon Severinsson
> // SPDX-License-Identifier: BSD-2-Clause ...
> ========== file03.c ==========
> // Copyright (c) 2008 The NetBSD Foundation, Inc.
> // SPDX-License-Identifier: BSD-2-Clause-NetBSD

This is an example which is AFAIU purported to show the problem with
various BSD licenses in a comment from someone. The order of the copyright
holder and license lines might be just random. The practice in kernel at
least appears to be SPDX license first.

-- 
Regards,

Sakari Ailus
sakari.ailus@linux.intel.com

Re: RESEND[PATCH v6 1/2] media: dt-bindings: Add bindings for Dongwoon DW9807 voice coil

[Rob Herring]

On Sat, Mar 17, 2018 at 01:05:25AM +0800, Andy Yeh wrote:
> From: Alan Chiang <alanx.chiang@intel.com>
> 
> Dongwoon DW9807 is a voice coil lens driver.
> 
> Signed-off-by: Andy Yeh <andy.yeh@intel.com>
> ---
>  Documentation/devicetree/bindings/media/i2c/dongwoon,dw9807.txt | 9 +++++++++
>  1 file changed, 9 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/media/i2c/dongwoon,dw9807.txt

Reviewed-by: Rob Herring <robh@kernel.org>

RE: RESEND[PATCH v6 2/2] media: dw9807: Add dw9807 vcm driver

[Yeh, Andy]

Got it. We shall reverse the order in the later submission on list.

Regards, Andy

-----Original Message-----
From: sakari.ailus@linux.intel.com [mailto:sakari.ailus@linux.intel.com] 
Sent: Thursday, March 22, 2018 1:07 AM
To: Yeh, Andy <andy.yeh@intel.com>
Cc: jacopo mondi <jacopo@jmondi.org>; linux-media@vger.kernel.org; devicetree@vger.kernel.org; Chiang, AlanX <alanx.chiang@intel.com>
Subject: Re: RESEND[PATCH v6 2/2] media: dw9807: Add dw9807 vcm driver

Hi Andy,

On Wed, Mar 21, 2018 at 03:58:42PM +0000, Yeh, Andy wrote:
> Thanks for the comments. A quick question first. For the reset we need some time to address.
> 
> -----Original Message-----
> From: jacopo mondi [mailto:jacopo@jmondi.org]
> Sent: Tuesday, March 20, 2018 6:28 PM
> To: Yeh, Andy <andy.yeh@intel.com>
> Cc: linux-media@vger.kernel.org; sakari.ailus@linux.intel.com; 
> devicetree@vger.kernel.org; Chiang, AlanX <alanx.chiang@intel.com>
> Subject: Re: RESEND[PATCH v6 2/2] media: dw9807: Add dw9807 vcm driver
> 
> Hi Andy,
>    a few comments on you patch below...
> 
> On Sat, Mar 17, 2018 at 01:05:26AM +0800, Andy Yeh wrote:
> > From: Alan Chiang <alanx.chiang@intel.com> 
> > a/drivers/media/i2c/dw9807.c b/drivers/media/i2c/dw9807.c new file 
> > mode 100644 index 0000000..95626e9
> > --- /dev/null
> > +++ b/drivers/media/i2c/dw9807.c
> > @@ -0,0 +1,320 @@
> > +// Copyright (C) 2018 Intel Corporation // SPDX-License-Identifier: 
> > +GPL-2.0
> > +
> 
> Nit: my understanding is that the SPDX identifier goes first
> 
> https://lwn.net/Articles/739183/
> 
> I checked this site. And it says Copyright should be before SPDX identifier.
> ========== file01.c ==========
> // Copyright (c) 2012-2016 Joe Random Hacker // SPDX-License-Identifier: BSD-2-Clause ...
> ========== file02.c ==========
> // Copyright (c) 2017 Jon Severinsson
> // SPDX-License-Identifier: BSD-2-Clause ...
> ========== file03.c ==========
> // Copyright (c) 2008 The NetBSD Foundation, Inc.
> // SPDX-License-Identifier: BSD-2-Clause-NetBSD

This is an example which is AFAIU purported to show the problem with various BSD licenses in a comment from someone. The order of the copyright holder and license lines might be just random. The practice in kernel at least appears to be SPDX license first.

--
Regards,

Sakari Ailus
sakari.ailus@linux.intel.com

RE: RESEND[PATCH v6 2/2] media: dw9807: Add dw9807 vcm driver

[Yeh, Andy]

Hi Jacopo,

Excuse for late reply, we were busy in past weeks for major milestone. Please kindly check the revised V7 which has been uploaded.
https://patchwork.linuxtv.org/patch/48589/

Responded to your comments as below.

Cc in Tomasz for unintentionally missed.

Regards, Andy

-----Original Message-----
From: jacopo mondi [mailto:jacopo@jmondi.org] 
Sent: Tuesday, March 20, 2018 6:28 PM
To: Yeh, Andy <andy.yeh@intel.com>
Cc: linux-media@vger.kernel.org; sakari.ailus@linux.intel.com; devicetree@vger.kernel.org; Chiang, AlanX <alanx.chiang@intel.com>
Subject: Re: RESEND[PATCH v6 2/2] media: dw9807: Add dw9807 vcm driver

Hi Andy,
   a few comments on you patch below...

On Sat, Mar 17, 2018 at 01:05:26AM +0800, Andy Yeh wrote:
> From: Alan Chiang <alanx.chiang@intel.com>
>
> DW9807 is a 10 bit DAC from Dongwoon, designed for linear control of 
> voice coil motor.
>
> This driver creates a V4L2 subdevice and provides control to set the 
> desired focus.
>
> Signed-off-by: Andy Yeh <andy.yeh@intel.com>
> ---
> since v1:
> - changed author.
> since v2:
> - addressed outstanding comments.
> - enabled sequential write to update 2 registers in a single transaction.
> since v3:
> - addressed comments for v3.
> - Remove redundant codes and declare some variables as constant variable.
> - separate DT binding to another patch sicne v4:
> - sent patchset included DT binding with cover page
>
>  MAINTAINERS                |   7 +
>  drivers/media/i2c/Kconfig  |  10 ++
>  drivers/media/i2c/Makefile |   1 +
>  drivers/media/i2c/dw9807.c | 320 
> +++++++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 338 insertions(+)
>  create mode 100644 drivers/media/i2c/dw9807.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS index 845fc25..a339bb5 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -4385,6 +4385,13 @@ T:	git git://linuxtv.org/media_tree.git
>  S:	Maintained
>  F:	drivers/media/i2c/dw9714.c
>
> +DONGWOON DW9807 LENS VOICE COIL DRIVER
> +M:	Sakari Ailus <sakari.ailus@linux.intel.com>
> +L:	linux-media@vger.kernel.org
> +T:	git git://linuxtv.org/media_tree.git
> +S:	Maintained
> +F:	drivers/media/i2c/dw9807.c
> +
>  DOUBLETALK DRIVER
>  M:	"James R. Van Zandt" <jrv@vanzandt.mv.com>
>  L:	blinux-list@redhat.com
> diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig 
> index cb5d7ff..fd01842 100644
> --- a/drivers/media/i2c/Kconfig
> +++ b/drivers/media/i2c/Kconfig
> @@ -325,6 +325,16 @@ config VIDEO_DW9714
>  	  capability. This is designed for linear control of
>  	  voice coil motors, controlled via I2C serial interface.
>
> +config VIDEO_DW9807
> +	tristate "DW9807 lens voice coil support"
> +	depends on I2C && VIDEO_V4L2 && MEDIA_CONTROLLER
> +	depends on VIDEO_V4L2_SUBDEV_API
> +	---help---
> +	  This is a driver for the DW9807 camera lens voice coil.
> +	  DW9807 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_SAA7110
>  	tristate "Philips SAA7110 video decoder"
>  	depends on VIDEO_V4L2 && I2C
> diff --git a/drivers/media/i2c/Makefile b/drivers/media/i2c/Makefile 
> index 548a9ef..1b62639 100644
> --- a/drivers/media/i2c/Makefile
> +++ b/drivers/media/i2c/Makefile
> @@ -23,6 +23,7 @@ obj-$(CONFIG_VIDEO_SAA7185) += saa7185.o
>  obj-$(CONFIG_VIDEO_SAA6752HS) += saa6752hs.o
>  obj-$(CONFIG_VIDEO_AD5820)  += ad5820.o
>  obj-$(CONFIG_VIDEO_DW9714)  += dw9714.o
> +obj-$(CONFIG_VIDEO_DW9807)  += dw9807.o
>  obj-$(CONFIG_VIDEO_ADV7170) += adv7170.o
>  obj-$(CONFIG_VIDEO_ADV7175) += adv7175.o
>  obj-$(CONFIG_VIDEO_ADV7180) += adv7180.o diff --git 
> a/drivers/media/i2c/dw9807.c b/drivers/media/i2c/dw9807.c new file 
> mode 100644 index 0000000..95626e9
> --- /dev/null
> +++ b/drivers/media/i2c/dw9807.c
> @@ -0,0 +1,320 @@
> +// Copyright (C) 2018 Intel Corporation // SPDX-License-Identifier: 
> +GPL-2.0
> +

> Nit: my understanding is that the SPDX identifier goes first

Done

> +#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 DW9807_NAME		"dw9807"
> +#define DW9807_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

> Please end comments with a full stop, here and in the rest of the driver.

Done

> + */
> +#define DW9807_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 DW9807_CTRL_STEPS	16
> +#define DW9807_CTRL_DELAY_US	1000
> +
> +#define DW9807_CTL_ADDR		0x02
> +/*
> + * DW9807 separates two registers to control the VCM position.
> + * One for MSB value, another is LSB value.
> + */
> +#define DW9807_MSB_ADDR		0x03
> +#define DW9807_LSB_ADDR		0x04
> +#define DW9807_STATUS_ADDR	0x05
> +#define DW9807_MODE_ADDR	0x06
> +#define DW9807_RESONANCE_ADDR	0x07
> +
> +#define MAX_RETRY		10
> +
> +struct dw9807_device {
> +	struct v4l2_ctrl_handler ctrls_vcm;
> +	struct v4l2_subdev sd;
> +	u16 current_val;
> +};
> +
> +static inline struct dw9807_device *sd_to_dw9807_vcm(struct 
> +v4l2_subdev *subdev) {
> +	return container_of(subdev, struct dw9807_device, sd); }
> +
> +static int dw9807_i2c_check(struct i2c_client *client) {
> +	const char status_addr = DW9807_STATUS_ADDR;
> +	char status_result = 0x1;

> Do you need to intialize this?

This is not necessary, remove it. Done.

> +	int ret;
> +
> +	ret = i2c_master_send(client, (const char *)&status_addr, sizeof(status_addr));
> +	if (ret != sizeof(status_addr)) {

> I think ret is either < 0 or the buffer length byte count.

> i2c_master_send() calls i2c_transfer_buffer_flags that uses i2c_transfer().
> i2c_transfer returns either an error code, or the number of i2c messages transfered.

> i2c_master_send(client, buf, count):
>         return i2c_transfer_buffer_flags(client, buf, count, 0):
>                 ret = i2c_transfer(adapter, buf, count);
>                 return (ret == 1) ? count : ret;

Only check the error code currently. Done.


> +		dev_err(&client->dev, "I2C write STATUS address fail ret = %d\n",
> +			ret);
> +		return -EIO;

> please consider returning ret to propagate the i2c error

Done

> +	}
> +
> +	ret = i2c_master_recv(client, (char *)&status_result, sizeof(status_result));
> +	if (ret != sizeof(status_result)) {
> +		dev_err(&client->dev, "I2C read STATUS value fail ret=%d\n",
> +			ret);
> +		return -EIO;
> +	}

> same here

Done

> +
> +	return status_result;
> +}
> +
> +static int dw9807_set_dac(struct i2c_client *client, u16 data) {
> +	const char tx_data[3] = {
> +		DW9807_MSB_ADDR, ((data >> 8) & 0x03), (data & 0xFF) };

> lowercase for hex (0xff).
> Also, this is not a general rule, but, could you consider closing the brace on next line?

Done

> +	int ret, retry = 0;
> +
> +	/*
> +	 * According to the datasheet, need to check the bus status before we
> +	 * write VCM position. This ensure that we really write the value
> +	 * into the register
> +	 */
> +	while (dw9807_i2c_check(client) != 0) {

> Up to you, but with this check, you are ignoring i2c errors

Check the i2c error as well. Done.

> +		if (MAX_RETRY == ++retry) {
> +			dev_err(&client->dev, "Cannot do the write operation because VCM is busy\n");
> +			return -EIO;
> +		}
> +		usleep_range(DW9807_CTRL_DELAY_US, DW9807_CTRL_DELAY_US + 10);
> +	}
> +
> +	/* Write VCM position to registers */
> +	ret = i2c_master_send(client, tx_data, sizeof(tx_data));
> +	if (ret != sizeof(tx_data)) {
> +		dev_err(&client->dev, "I2C write MSB fail\n");

> Same as above. Check for < 0 and please printout the error code in the error message (and consider propagating to the caller).

Check the i2c error as well. Done.

> +		return -EIO;
> +	}
> +
> +	return 0;
> +}
> +
> +static int dw9807_set_ctrl(struct v4l2_ctrl *ctrl) {
> +	struct dw9807_device *dev_vcm = container_of(ctrl->handler, struct 
> +dw9807_device, ctrls_vcm);

> This seems clearly longer than 80 cols. Have you run checkpatch on this?

truncate this line. Done.

> +
> +	if (ctrl->id == V4L2_CID_FOCUS_ABSOLUTE) {
> +		struct i2c_client *client = v4l2_get_subdevdata(&dev_vcm->sd);
> +
> +		dev_vcm->current_val = ctrl->val;
> +		return dw9807_set_dac(client, ctrl->val);
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +static const struct v4l2_ctrl_ops dw9807_vcm_ctrl_ops = {
> +	.s_ctrl = dw9807_set_ctrl,
> +};
> +
> +static int dw9807_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);

> If you fail to get pm context, no need to put it back (I presume)

According to Sakari Ailus's comment on LinuxTV.
(pm_runtime_get() must be followed by pm_runtime_put() whether the former
succeeds or not.)
So it is no need to modify.

> +		return rval;
> +	}
> +
> +	return 0;
> +}
> +
> +static int dw9807_close(struct v4l2_subdev *sd, struct v4l2_subdev_fh 
> +*fh) {
> +	pm_runtime_put(sd->dev);
> +
> +	return 0;
> +}
> +
> +static const struct v4l2_subdev_internal_ops dw9807_int_ops = {
> +	.open = dw9807_open,
> +	.close = dw9807_close,
> +};
> +
> +static const struct v4l2_subdev_ops dw9807_ops = { };
> +
> +static void dw9807_subdev_cleanup(struct dw9807_device *dw9807_dev) {
> +	v4l2_async_unregister_subdev(&dw9807_dev->sd);
> +	v4l2_ctrl_handler_free(&dw9807_dev->ctrls_vcm);
> +	media_entity_cleanup(&dw9807_dev->sd.entity);
> +}
> +
> +static int dw9807_init_controls(struct dw9807_device *dev_vcm) {
> +	struct v4l2_ctrl_handler *hdl = &dev_vcm->ctrls_vcm;
> +	const struct v4l2_ctrl_ops *ops = &dw9807_vcm_ctrl_ops;
> +	struct i2c_client *client = v4l2_get_subdevdata(&dev_vcm->sd);
> +
> +	v4l2_ctrl_handler_init(hdl, 1);
> +
> +	v4l2_ctrl_new_std(hdl, ops, V4L2_CID_FOCUS_ABSOLUTE,
> +			  0, DW9807_MAX_FOCUS_POS, DW9807_FOCUS_STEPS, 0);
> +
> +	dev_vcm->sd.ctrl_handler = hdl;
> +	if (hdl->error) {
> +		dev_err(&client->dev, "%s fail error: 0x%x\n",
> +			__func__, hdl->error);
> +		return hdl->error;
> +	}
> +
> +	return 0;
> +}
> +
> +static int dw9807_probe(struct i2c_client *client) {
> +	struct dw9807_device *dw9807_dev;
> +	int rval;
> +
> +	dw9807_dev = devm_kzalloc(&client->dev, sizeof(*dw9807_dev),
> +				  GFP_KERNEL);
> +	if (dw9807_dev == NULL)

> if (!dw9807) or checkpatch complains

Done

> +		return -ENOMEM;
> +
> +	v4l2_i2c_subdev_init(&dw9807_dev->sd, client, &dw9807_ops);
> +	dw9807_dev->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
> +	dw9807_dev->sd.internal_ops = &dw9807_int_ops;
> +
> +	rval = dw9807_init_controls(dw9807_dev);
> +	if (rval)
> +		goto err_cleanup;
> +
> +	rval = media_entity_pads_init(&dw9807_dev->sd.entity, 0, NULL);
> +	if (rval < 0)
> +		goto err_cleanup;
> +
> +	dw9807_dev->sd.entity.function = MEDIA_ENT_F_LENS;
> +
> +	rval = v4l2_async_register_subdev(&dw9807_dev->sd);
> +	if (rval < 0)
> +		goto err_cleanup;
> +
> +	pm_runtime_set_active(&client->dev);
> +	pm_runtime_enable(&client->dev);
> +	pm_runtime_idle(&client->dev);
> +
> +	return 0;
> +
> +err_cleanup:
> +	dw9807_subdev_cleanup(dw9807_dev);

> empty line before return maybe?

Add a line. Done.

> +	return rval;
> +}
> +
> +static int dw9807_remove(struct i2c_client *client) {
> +	struct v4l2_subdev *sd = i2c_get_clientdata(client);
> +	struct dw9807_device *dw9807_dev = sd_to_dw9807_vcm(sd);
> +
> +	pm_runtime_disable(&client->dev);
> +	pm_runtime_set_suspended(&client->dev);
> +
> +	dw9807_subdev_cleanup(dw9807_dev);
> +
> +	return 0;
> +}
> +
> +/*
> + * This function sets the vcm position, so it consumes least current
> + * The lens position is gradually moved in units of 
> +DW9807_CTRL_STEPS,
> + * to make the movements smoothly.
> + */
> +static int __maybe_unused dw9807_vcm_suspend(struct device *dev) {
> +	struct i2c_client *client = to_i2c_client(dev);
> +	struct v4l2_subdev *sd = i2c_get_clientdata(client);
> +	struct dw9807_device *dw9807_dev = sd_to_dw9807_vcm(sd);
> +	const char tx_data[2] = { DW9807_CTL_ADDR, 0x01 };
> +	int ret, val;
> +
> +	for (val = dw9807_dev->current_val & ~(DW9807_CTRL_STEPS - 1);
> +	     val >= 0; val -= DW9807_CTRL_STEPS) {
> +		ret = dw9807_set_dac(client, val);
> +		if (ret)
> +			dev_err_once(dev, "%s I2C failure: %d", __func__, ret);
> +		usleep_range(DW9807_CTRL_DELAY_US, DW9807_CTRL_DELAY_US + 10);
> +	}
> +
> +	/* Power down */
> +	ret = i2c_master_send(client, tx_data, sizeof(tx_data));
> +
> +	if (ret != sizeof(tx_data)) {
> +		dev_err(&client->dev, "I2C write CTL fail\n");
> +		return -EIO;
> +	}
> +
> +	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 
> +DW9807_CTRL_STEPS,
> + * to make the movements smoothly.
> + */
> +static int  __maybe_unused dw9807_vcm_resume(struct device *dev) {
> +	struct i2c_client *client = to_i2c_client(dev);
> +	struct v4l2_subdev *sd = i2c_get_clientdata(client);
> +	struct dw9807_device *dw9807_dev = sd_to_dw9807_vcm(sd);
> +	const char tx_data[2] = { DW9807_CTL_ADDR, 0x00 };
> +	int ret, val;
> +
> +	/* Power on */
> +	ret = i2c_master_send(client, tx_data, sizeof(tx_data));
> +	if (ret != sizeof(tx_data)) {
> +		dev_err(&client->dev, "I2C write CTL fail\n");
> +		return -EIO;
> +	}
> +
> +	for (val = dw9807_dev->current_val % DW9807_CTRL_STEPS;
> +	     val < dw9807_dev->current_val + DW9807_CTRL_STEPS - 1;
> +	     val += DW9807_CTRL_STEPS) {
> +		ret = dw9807_set_dac(client, val);
> +		if (ret)
> +			dev_err_ratelimited(dev, "%s I2C failure: %d",
> +						__func__, ret);
> +		usleep_range(DW9807_CTRL_DELAY_US, DW9807_CTRL_DELAY_US + 10);
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id dw9807_of_table[] = {
> +	{ .compatible = "dongwoon,dw9807" },
> +	{ { 0 } }

> { } is enough.
According to Sakari Ailus's comment on LinuxTV.
{ } is GCC specific while { { 0 } } isn't.
And if I remove it, compile error will occur.

> +};
> +MODULE_DEVICE_TABLE(of, dw9807_of_table);
> +
> +static const struct dev_pm_ops dw9807_pm_ops = {
> +	SET_SYSTEM_SLEEP_PM_OPS(dw9807_vcm_suspend, dw9807_vcm_resume)
> +	SET_RUNTIME_PM_OPS(dw9807_vcm_suspend, dw9807_vcm_resume, NULL) };
> +
> +static struct i2c_driver dw9807_i2c_driver = {
> +	.driver = {
> +		.name = DW9807_NAME,

> That DW9807_NAME define is used only here.

Done

> Thanks
>   j


> +		.pm = &dw9807_pm_ops,
> +		.of_match_table = dw9807_of_table,
> +	},
> +	.probe_new = dw9807_probe,
> +	.remove = dw9807_remove,
> +};
> +
> +module_i2c_driver(dw9807_i2c_driver);
> +
> +MODULE_AUTHOR("Chiang, Alan <alanx.chiang@intel.com>");
> +MODULE_DESCRIPTION("DW9807 VCM driver"); MODULE_LICENSE("GPL v2");
> --
> 2.7.4
>

Re: RESEND[PATCH v6 2/2] media: dw9807: Add dw9807 vcm driver

[Tomasz Figa]

Hi Andy,

On Wed, Apr 11, 2018 at 12:54 AM Yeh, Andy <andy.yeh@intel.com> wrote:

> Hi Jacopo,

> Excuse for late reply, we were busy in past weeks for major milestone.
Please kindly check the revised V7 which has been uploaded.
> https://patchwork.linuxtv.org/patch/48589/

> Responded to your comments as below.

> Cc in Tomasz for unintentionally missed.

> Regards, Andy
[snip]
> > +static int dw9807_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);

> > If you fail to get pm context, no need to put it back (I presume)

> According to Sakari Ailus's comment on LinuxTV.
> (pm_runtime_get() must be followed by pm_runtime_put() whether the former
> succeeds or not.)
> So it is no need to modify.

Andy is right. pm_runtime_get() always acquires a PM runtime count, even in
case of error.

[snip]
> > +static const struct of_device_id dw9807_of_table[] = {
> > +     { .compatible = "dongwoon,dw9807" },
> > +     { { 0 } }

> > { } is enough.
> According to Sakari Ailus's comment on LinuxTV.
> { } is GCC specific while { { 0 } } isn't.
> And if I remove it, compile error will occur.

Hmm, we're in the heavy nitpicking territory here, but

{ },

is the typical pattern used throughout the kernel. I personally actually
put a comment inside:

{ /* sentinel */ },

Just my opinion. I'm fine with keeping it either way, if no need to re-spin
for other changes.

Best regards,
Tomasz