[PATCH 2/2] media: i2c: dw9768: Add DW9768 VCM driver

[<dongchun.zhu@mediatek.com>]

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

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 | 458 +++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 470 insertions(+)
 create mode 100644 drivers/media/i2c/dw9768.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 8f6ac93..17152d7 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -4877,6 +4877,7 @@ 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 7793358..8ff6c95 100644
--- a/drivers/media/i2c/Kconfig
+++ b/drivers/media/i2c/Kconfig
@@ -1014,6 +1014,16 @@ 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 d8ad9da..944fbf6 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..f5b5591
--- /dev/null
+++ b/drivers/media/i2c/dw9768.c
@@ -0,0 +1,458 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2018 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_VOLTAGE_ANALOG			2800000
+#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
+
+#define DW9768_CTRL_DELAY_US			5000
+
+#define DW9768_REG_DAC_MSB			0x03
+#define DW9768_REG_DAC_LSB			0x04
+#define DW9768_REG_NULL				0xff
+
+#define DW9768_DAC_SHIFT			8
+
+#define DW9768_REG_VALUE_16BIT			2
+
+/* dw9768 device structure */
+struct dw9768_device {
+	struct v4l2_ctrl_handler ctrls;
+	struct v4l2_subdev sd;
+	struct regulator *analog_regulator;
+	/*
+	 * Serialize control access, get/set format, get selection
+	 * and start streaming.
+	 */
+	struct mutex power_lock;
+
+	int power_count;
+	bool standby;
+};
+
+static inline struct dw9768_device *to_dw9768_vcm(struct v4l2_ctrl *ctrl)
+{
+	return container_of(ctrl->handler, struct dw9768_device, ctrls);
+}
+
+static inline struct dw9768_device *sd_to_dw9768_vcm(struct v4l2_subdev *subdev)
+{
+	return container_of(subdev, struct dw9768_device, sd);
+}
+
+static int dw9768_i2c_write(struct dw9768_device *dw9768_dev, u8 *data,
+			    int size)
+{
+	struct i2c_client *client = v4l2_get_subdevdata(&dw9768_dev->sd);
+	struct i2c_msg msg;
+	u8 *w_buf = NULL;
+	u8 retry_cnt = 3;
+	int ret;
+
+	if (!client->adapter)
+		return -ENODEV;
+
+	if (size != 1 && size != 2)
+		return -EINVAL;
+
+	memset(&msg, 0, sizeof(struct i2c_msg));
+
+	w_buf = kzalloc(size, GFP_KERNEL);
+	if (!w_buf)
+		return -1;
+
+	memcpy(w_buf, data, size);
+
+	msg.addr  = client->addr;
+	msg.flags = 0;
+	msg.len   = size;
+	msg.buf   = w_buf;
+
+	do {
+		ret = i2c_transfer(client->adapter, &msg, 1);
+		if (ret != 1)
+			dev_err(&client->dev, "write fail, ret:%d, retry:%d\n",
+				ret, retry_cnt);
+		else
+			break;
+		retry_cnt--;
+	} while (retry_cnt != 0);
+
+	if (retry_cnt == 0)	{
+		dev_err(&client->dev, "i2c write fail(%d)\n", ret);
+		return -EIO;
+	}
+
+	kfree(w_buf);
+
+	return 0;
+}
+
+static int dw9768_release(struct dw9768_device *dw9768_dev)
+{
+	unsigned char i;
+	int ret;
+
+	char puSendCmdArray[4][2] = {
+		{0x02, 0x00}, {DW9768_REG_NULL, DW9768_REG_NULL},
+		{0x01, 0x00}, {DW9768_REG_NULL, DW9768_REG_NULL},
+	};
+
+	for (i = 0; i < (sizeof(puSendCmdArray) / sizeof(char)) /
+	     (sizeof(puSendCmdArray[0]) / sizeof(char)); i++) {
+		if (puSendCmdArray[i][0] != DW9768_REG_NULL) {
+			ret = dw9768_i2c_write(dw9768_dev, puSendCmdArray[i],
+					       DW9768_REG_VALUE_16BIT);
+			if (ret < 0)
+				return ret;
+		} else {
+			usleep_range(DW9768_CTRL_DELAY_US,
+				     DW9768_CTRL_DELAY_US + 100);
+		}
+	}
+
+	return 0;
+}
+
+static int dw9768_init(struct dw9768_device *dw9768_dev)
+{
+	unsigned char i;
+	int ret;
+
+	char puSendCmdArray[5][2] = {
+		{0x02, 0x02}, {DW9768_REG_NULL, DW9768_REG_NULL},
+		{0x06, 0x41}, {0x07, 0x39}, {DW9768_REG_NULL, DW9768_REG_NULL},
+	};
+
+	for (i = 0; i < (sizeof(puSendCmdArray) / sizeof(char)) /
+	     (sizeof(puSendCmdArray[0]) / sizeof(char)); i++) {
+		if (puSendCmdArray[i][0] != DW9768_REG_NULL) {
+			ret = dw9768_i2c_write(dw9768_dev, puSendCmdArray[i],
+					       DW9768_REG_VALUE_16BIT);
+			if (ret < 0)
+				return ret;
+		} else {
+			usleep_range(DW9768_CTRL_DELAY_US,
+				     DW9768_CTRL_DELAY_US + 100);
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * Power handling
+ */
+static int dw9768_power_off(struct dw9768_device *dw9768_dev, bool standby)
+{
+	struct i2c_client *client = v4l2_get_subdevdata(&dw9768_dev->sd);
+	int ret;
+
+	/*
+	 * Go to standby first as real power off my be denied by the hardware
+	 * (single power line control for both dw9768_dev and sensor).
+	 */
+	if (standby) {
+		dw9768_dev->standby = true;
+		ret = dw9768_release(dw9768_dev);
+		if (ret)
+			dev_err(&client->dev, "dw9768_release failed!\n");
+	}
+	ret = regulator_disable(dw9768_dev->analog_regulator);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int dw9768_power_on(struct dw9768_device *dw9768_dev, bool restore)
+{
+	int ret;
+
+	ret = regulator_enable(dw9768_dev->analog_regulator);
+	if (ret < 0)
+		return ret;
+
+	if (restore) {
+		/* Restore the hardware settings. */
+		dw9768_dev->standby = false;
+		ret = dw9768_init(dw9768_dev);
+		if (ret < 0)
+			goto fail;
+	}
+
+	return 0;
+
+fail:
+	dw9768_dev->standby = true;
+	regulator_disable(dw9768_dev->analog_regulator);
+
+	return ret;
+}
+
+/*
+ * Calculate status word and write it to the device based on current
+ * values of V4L2 controls. It is assumed that the stored V4L2 control
+ * values are properly limited and rounded.
+ */
+static int dw9768_update_hw(struct dw9768_device *dw9768_dev, u16 val)
+{
+	unsigned char i;
+	int ret;
+
+	char puSendCmdArray[2][2] = {
+		{DW9768_REG_DAC_MSB, (char)(val >> DW9768_DAC_SHIFT)},
+		{DW9768_REG_DAC_LSB, (char)(val & 0xFF)},
+	};
+
+	for (i = 0; i < (sizeof(puSendCmdArray) / sizeof(char)) /
+	     (sizeof(puSendCmdArray[0]) / sizeof(char)); i++) {
+		ret = dw9768_i2c_write(dw9768_dev, puSendCmdArray[i],
+				       DW9768_REG_VALUE_16BIT);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int dw9768_set_ctrl(struct v4l2_ctrl *ctrl)
+{
+	struct dw9768_device *dw9768_dev = to_dw9768_vcm(ctrl);
+
+	if (ctrl->id == V4L2_CID_FOCUS_ABSOLUTE)
+		return dw9768_update_hw(dw9768_dev, ctrl->val);
+
+	return 0;
+}
+
+static const struct v4l2_ctrl_ops dw9768_vcm_ctrl_ops = {
+	.s_ctrl = dw9768_set_ctrl,
+};
+
+static int
+dw9768_set_power(struct v4l2_subdev *subdev, int on)
+{
+	struct dw9768_device *dw9768_dev = sd_to_dw9768_vcm(subdev);
+	int ret = 0;
+
+	mutex_lock(&dw9768_dev->power_lock);
+
+	/*
+	 * If the power count is modified from 0 to != 0 or from != 0 to 0,
+	 * update the power state.
+	 */
+	if (dw9768_dev->power_count == !on) {
+		ret = on ? dw9768_power_on(dw9768_dev, true) :
+			dw9768_power_off(dw9768_dev, true);
+		if (ret < 0)
+			goto done;
+	}
+
+	/* Update the power count. */
+	dw9768_dev->power_count += on ? 1 : -1;
+	WARN_ON(dw9768_dev->power_count < 0);
+
+done:
+	mutex_unlock(&dw9768_dev->power_lock);
+	return ret;
+}
+
+static int dw9768_open(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
+{
+	return dw9768_set_power(sd, 1);
+}
+
+static int dw9768_close(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
+{
+	return dw9768_set_power(sd, 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_device *dw9768_dev)
+{
+	v4l2_async_unregister_subdev(&dw9768_dev->sd);
+	v4l2_ctrl_handler_free(&dw9768_dev->ctrls);
+	media_entity_cleanup(&dw9768_dev->sd.entity);
+}
+
+static int dw9768_init_controls(struct dw9768_device *dw9768_dev)
+{
+	struct v4l2_ctrl_handler *hdl = &dw9768_dev->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) {
+		dev_err(dw9768_dev->sd.dev, "%s fail error: 0x%x\n",
+			__func__, hdl->error);
+		return hdl->error;
+	}
+
+	dw9768_dev->sd.ctrl_handler = hdl;
+
+	return 0;
+}
+
+static int dw9768_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct dw9768_device *dw9768_dev;
+	int rval;
+
+	dw9768_dev = devm_kzalloc(&client->dev, sizeof(*dw9768_dev),
+				  GFP_KERNEL);
+	if (!dw9768_dev)
+		return -ENOMEM;
+
+	dw9768_dev->analog_regulator = devm_regulator_get(dev, "afvdd");
+	if (IS_ERR(dw9768_dev->analog_regulator)) {
+		dev_err(dev, "cannot get analog regulator\n");
+		return PTR_ERR(dw9768_dev->analog_regulator);
+	}
+
+	rval = regulator_set_voltage(dw9768_dev->analog_regulator,
+				     DW9768_VOLTAGE_ANALOG,
+				     DW9768_VOLTAGE_ANALOG);
+	if (rval < 0) {
+		dev_err(dev, "cannot set analog voltage\n");
+		return rval;
+	}
+
+	mutex_init(&dw9768_dev->power_lock);
+
+	v4l2_i2c_subdev_init(&dw9768_dev->sd, client, &dw9768_ops);
+	dw9768_dev->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
+	dw9768_dev->sd.internal_ops = &dw9768_int_ops;
+
+	rval = dw9768_init_controls(dw9768_dev);
+	if (rval)
+		goto err_cleanup;
+
+	rval = media_entity_pads_init(&dw9768_dev->sd.entity, 0, NULL);
+	if (rval < 0)
+		goto err_cleanup;
+
+	dw9768_dev->sd.entity.function = MEDIA_ENT_F_LENS;
+
+	rval = v4l2_async_register_subdev(&dw9768_dev->sd);
+	if (rval < 0)
+		goto err_cleanup;
+
+	pm_runtime_set_active(dev);
+	pm_runtime_enable(dev);
+	pm_runtime_idle(dev);
+
+	return 0;
+
+err_cleanup:
+	mutex_destroy(&dw9768_dev->power_lock);
+	dw9768_subdev_cleanup(dw9768_dev);
+	dev_err(dev, "Probe failed: %d\n", rval);
+	return rval;
+}
+
+static int dw9768_remove(struct i2c_client *client)
+{
+	struct v4l2_subdev *sd = i2c_get_clientdata(client);
+	struct dw9768_device *dw9768_dev = sd_to_dw9768_vcm(sd);
+
+	pm_runtime_disable(&client->dev);
+	dw9768_subdev_cleanup(dw9768_dev);
+
+	return 0;
+}
+
+/*
+ * This function sets the vcm position, so it consumes least current
+ * The lens position is gradually moved in units of DW9768_CTRL_STEPS,
+ * to make the movements smoothly.
+ */
+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_device *dw9768_dev = sd_to_dw9768_vcm(sd);
+
+	if (!dw9768_dev->power_count)
+		return 0;
+
+	return dw9768_power_off(dw9768_dev, false);
+}
+
+/*
+ * 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 DW9768_CTRL_STEPS,
+ * to make the movements smoothly.
+ */
+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_device *dw9768_dev = sd_to_dw9768_vcm(sd);
+
+	if (!dw9768_dev->power_count)
+		return 0;
+
+	return dw9768_power_on(dw9768_dev, true);
+}
+
+static const struct i2c_device_id dw9768_id_table[] = {
+	{ DW9768_NAME, 0 },
+	{ { 0 } }
+};
+MODULE_DEVICE_TABLE(i2c, dw9768_id_table);
+
+static const struct of_device_id dw9768_of_table[] = {
+	{ .compatible = "dongwoon,dw9768" },
+	{ { 0 } }
+};
+MODULE_DEVICE_TABLE(of, dw9768_of_table);
+
+static const struct dev_pm_ops dw9768_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(dw9768_vcm_suspend, dw9768_vcm_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");
-- 
2.9.2