[PATCH v2 1/2] dt-bindings: Add bindings for AKM ak7375 voice coil lens

[PATCH v2 1/2] dt-bindings: Add bindings for AKM ak7375 voice coil lens

[bingbu.cao]

From: Bingbu Cao <bingbu.cao@intel.com>

Add device tree bindings for AKM ak7375 voice coil lens
driver. This chip is used to drive a lens in a camera module.

Signed-off-by: Tianshu Qiu <tian.shu.qiu@intel.com>
Signed-off-by: Bingbu Cao <bingbu.cao@intel.com>
---
Changes since v1:
 - remove the vendor prefix change
 
Documentation/devicetree/bindings/media/i2c/ak7375.txt | 8 ++++++++
 1 file changed, 8 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/media/i2c/ak7375.txt

diff --git a/Documentation/devicetree/bindings/media/i2c/ak7375.txt b/Documentation/devicetree/bindings/media/i2c/ak7375.txt
new file mode 100644
index 000000000000..aa3e24b41241
--- /dev/null
+++ b/Documentation/devicetree/bindings/media/i2c/ak7375.txt
@@ -0,0 +1,8 @@
+Asahi Kasei Microdevices AK7375 voice coil lens driver
+
+AK7375 is a camera voice coil lens.
+
+Mandatory properties:
+
+- compatible: "asahi-kasei,ak7375"
+- reg: I2C slave address
-- 
1.9.1

[PATCH v2 2/2] media: ak7375: Add ak7375 lens voice coil driver

[bingbu.cao]

From: Bingbu Cao <bingbu.cao@intel.com>

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.

Signed-off-by: Tianshu Qiu <tian.shu.qiu@intel.com>
Signed-off-by: Bingbu Cao <bingbu.cao@intel.com>
---
 MAINTAINERS                |   8 ++
 drivers/media/i2c/Kconfig  |  10 ++
 drivers/media/i2c/Makefile |   1 +
 drivers/media/i2c/ak7375.c | 278 +++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 297 insertions(+)
 create mode 100644 drivers/media/i2c/ak7375.c

diff --git a/MAINTAINERS b/MAINTAINERS
index ea362219c4aa..20379a7baca0 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -625,6 +625,14 @@ T:	git git://linuxtv.org/anttip/media_tree.git
 S:	Maintained
 F:	drivers/media/usb/airspy/
 
+AKM AK7375 LENS VOICE COIL DRIVER
+M:	Tianshu Qiu <tian.shu.qiu@intel.com>
+L:	linux-media@vger.kernel.org
+T:	git git://linuxtv.org/media_tree.git
+S:	Maintained
+F:	drivers/media/i2c/ak7375.c
+F:	Documentation/devicetree/bindings/media/i2c/akm,ak7375.txt
+
 ALACRITECH GIGABIT ETHERNET DRIVER
 M:	Lino Sanfilippo <LinoSanfilippo@gmx.de>
 S:	Maintained
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..012e673e9ced
--- /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[2] = data & 0xff;
+	if (size == 2)
+		buf[1] = data >> 8;
+	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;
+
+	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;
+	}
+	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 = "akm,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@intel.com>");
+MODULE_AUTHOR("Bingbu Cao <bingbu.cao@intel.com>");
+MODULE_DESCRIPTION("AK7375 VCM driver");
+MODULE_LICENSE("GPL v2");
-- 
1.9.1