[PATCH v2] dw9714: Initial driver for dw9714 VCM

[Rajmohan Mani <rajmohan.mani@intel.com>]

DW9714 is a 10 bit DAC, 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: Rajmohan Mani <rajmohan.mani@intel.com>
---
Changes in v2:
	- Addressed review comments from Hans Verkuil
	- Fixed a debug message typo
	- Got rid of a return variable
---
 drivers/media/i2c/Kconfig  |   9 ++
 drivers/media/i2c/Makefile |   1 +
 drivers/media/i2c/dw9714.c | 320 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 330 insertions(+)
 create mode 100644 drivers/media/i2c/dw9714.c

diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
index fd181c9..4f0a7ad 100644
--- a/drivers/media/i2c/Kconfig
+++ b/drivers/media/i2c/Kconfig
@@ -300,6 +300,15 @@ 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_DW9714
+	tristate "DW9714 lens voice coil support"
+	depends on I2C && VIDEO_V4L2 && MEDIA_CONTROLLER
+	---help---
+	  This is a driver for the DW9714 camera lens voice coil.
+	  DW9714 is a 10 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_SAA7110
 	tristate "Philips SAA7110 video decoder"
 	depends on VIDEO_V4L2 && I2C
diff --git a/drivers/media/i2c/Makefile b/drivers/media/i2c/Makefile
index 62323ec..987bd1f 100644
--- a/drivers/media/i2c/Makefile
+++ b/drivers/media/i2c/Makefile
@@ -21,6 +21,7 @@ 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-$(CONFIG_VIDEO_DW9714)  += dw9714.o
 obj-$(CONFIG_VIDEO_ADV7170) += adv7170.o
 obj-$(CONFIG_VIDEO_ADV7175) += adv7175.o
 obj-$(CONFIG_VIDEO_ADV7180) += adv7180.o
diff --git a/drivers/media/i2c/dw9714.c b/drivers/media/i2c/dw9714.c
new file mode 100644
index 0000000..cd6cde7
--- /dev/null
+++ b/drivers/media/i2c/dw9714.c
@@ -0,0 +1,320 @@
+/*
+ * Copyright (c) 2015--2017 Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version
+ * 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#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 DW9714_NAME		"dw9714"
+#define DW9714_MAX_FOCUS_POS	1023
+#define DW9714_CTRL_STEPS	16	/* Keep this value power of 2 */
+#define DW9714_CTRL_DELAY_US	1000
+/*
+ * S[3:2] = 0x00, codes per step for "Linear Slope Control"
+ * S[1:0] = 0x00, step period
+ */
+#define DW9714_DEFAULT_S 0x0
+#define DW9714_VAL(data, s) (u16)((data) << 4 | (s))
+
+/* dw9714 device structure */
+struct dw9714_device {
+	struct i2c_client *client;
+	struct v4l2_ctrl_handler ctrls_vcm;
+	struct v4l2_subdev sd;
+	u16 current_val;
+};
+
+#define to_dw9714_vcm(_ctrl)	\
+	container_of(_ctrl->handler, struct dw9714_device, ctrls_vcm)
+
+static int dw9714_i2c_write(struct i2c_client *client, u16 data)
+{
+	const int num_msg = 1;
+	int ret;
+	u16 val = cpu_to_be16(data);
+	struct i2c_msg msg = {
+		.addr = client->addr,
+		.flags = 0,
+		.len = sizeof(val),
+		.buf = (u8 *) &val,
+	};
+
+	ret = i2c_transfer(client->adapter, &msg, num_msg);
+
+	/*One retry */
+	if (ret != num_msg)
+		ret = i2c_transfer(client->adapter, &msg, num_msg);
+
+	if (ret != num_msg) {
+		dev_err(&client->dev, "I2C write fail\n");
+		return -EIO;
+	}
+	return 0;
+}
+
+static int dw9714_t_focus_vcm(struct dw9714_device *dw9714_dev, u16 val)
+{
+	struct i2c_client *client = dw9714_dev->client;
+
+	dev_dbg(&client->dev, "Setting new value VCM: %d\n", val);
+	dw9714_dev->current_val = val;
+
+	return dw9714_i2c_write(client, DW9714_VAL(val, DW9714_DEFAULT_S));
+}
+
+static int dw9714_set_ctrl(struct v4l2_ctrl *ctrl)
+{
+	struct dw9714_device *dev_vcm = to_dw9714_vcm(ctrl);
+
+	if (ctrl->id == V4L2_CID_FOCUS_ABSOLUTE)
+		return dw9714_t_focus_vcm(dev_vcm, ctrl->val);
+
+	return -EINVAL;
+}
+
+static const struct v4l2_ctrl_ops dw9714_vcm_ctrl_ops = {
+	.s_ctrl = dw9714_set_ctrl,
+};
+
+static int dw9714_init_controls(struct dw9714_device *dev_vcm)
+{
+	struct v4l2_ctrl_handler *hdl = &dev_vcm->ctrls_vcm;
+	const struct v4l2_ctrl_ops *ops = &dw9714_vcm_ctrl_ops;
+	struct i2c_client *client = dev_vcm->client;
+
+	v4l2_ctrl_handler_init(hdl, 1);
+
+	v4l2_ctrl_new_std(hdl, ops, V4L2_CID_FOCUS_ABSOLUTE,
+			  0, DW9714_MAX_FOCUS_POS, 1, 0);
+
+	if (hdl->error)
+		dev_err(&client->dev, "dw9714_init_controls fail\n");
+	dev_vcm->sd.ctrl_handler = hdl;
+	return hdl->error;
+}
+
+static void dw9714_subdev_cleanup(struct dw9714_device *dw9714_dev)
+{
+	v4l2_ctrl_handler_free(&dw9714_dev->ctrls_vcm);
+	v4l2_async_unregister_subdev(&dw9714_dev->sd);
+	v4l2_device_unregister_subdev(&dw9714_dev->sd);
+	media_entity_cleanup(&dw9714_dev->sd.entity);
+}
+
+static int dw9714_open(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
+{
+	struct dw9714_device *dw9714_dev = container_of(sd,
+							struct dw9714_device,
+							sd);
+	struct device *dev = &dw9714_dev->client->dev;
+
+	return pm_runtime_get_sync(dev);
+}
+
+static int dw9714_close(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
+{
+	struct dw9714_device *dw9714_dev = container_of(sd,
+							struct dw9714_device,
+							sd);
+	struct device *dev = &dw9714_dev->client->dev;
+
+	pm_runtime_put(dev);
+
+	return 0;
+}
+
+static const struct v4l2_subdev_internal_ops dw9714_int_ops = {
+	.open = dw9714_open,
+	.close = dw9714_close,
+};
+
+static const struct v4l2_subdev_ops dw9714_ops = { };
+
+static int dw9714_probe(struct i2c_client *client,
+			const struct i2c_device_id *devid)
+{
+	struct dw9714_device *dw9714_dev;
+	int rval;
+
+	dw9714_dev = devm_kzalloc(&client->dev, sizeof(*dw9714_dev),
+				  GFP_KERNEL);
+
+	if (dw9714_dev == NULL)
+		return -ENOMEM;
+
+	dw9714_dev->client = client;
+
+	v4l2_i2c_subdev_init(&dw9714_dev->sd, client, &dw9714_ops);
+	dw9714_dev->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
+	dw9714_dev->sd.internal_ops = &dw9714_int_ops;
+
+	rval = dw9714_init_controls(dw9714_dev);
+	if (rval)
+		goto err_cleanup;
+
+	rval = media_entity_pads_init(&dw9714_dev->sd.entity, 0, NULL);
+	if (rval < 0)
+		goto err_cleanup;
+
+	dw9714_dev->sd.entity.function = MEDIA_ENT_F_LENS;
+
+	rval = v4l2_async_register_subdev(&dw9714_dev->sd);
+	if (rval < 0)
+		goto err_cleanup;
+
+	pm_runtime_enable(&client->dev);
+
+	return 0;
+
+err_cleanup:
+	dw9714_subdev_cleanup(dw9714_dev);
+	dev_err(&client->dev, "Probe failed: %d\n", rval);
+	return rval;
+}
+
+static int dw9714_remove(struct i2c_client *client)
+{
+	struct v4l2_subdev *sd = i2c_get_clientdata(client);
+	struct dw9714_device *dw9714_dev = container_of(sd,
+							struct dw9714_device,
+							sd);
+
+	pm_runtime_disable(&client->dev);
+	dw9714_subdev_cleanup(dw9714_dev);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM
+
+static int dw9714_runtime_suspend(struct device *dev)
+{
+	return 0;
+}
+
+static int dw9714_runtime_resume(struct device *dev)
+{
+	return 0;
+}
+
+/* This function sets the vcm position, so it consumes least current */
+static int dw9714_suspend(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct v4l2_subdev *sd = i2c_get_clientdata(client);
+	struct dw9714_device *dw9714_dev = container_of(sd,
+							struct dw9714_device,
+							sd);
+	int ret, val;
+
+	dev_dbg(dev, "%s\n", __func__);
+
+	for (val = dw9714_dev->current_val & ~(DW9714_CTRL_STEPS - 1);
+	     val >= 0; val -= DW9714_CTRL_STEPS) {
+		ret = dw9714_i2c_write(client,
+				       DW9714_VAL((u16) val, DW9714_DEFAULT_S));
+		if (ret)
+			dev_err(dev, "%s I2C failure: %d", __func__, ret);
+		usleep_range(DW9714_CTRL_DELAY_US, DW9714_CTRL_DELAY_US + 10);
+	}
+	return 0;
+}
+
+/*
+ * This function sets the vcm position, so the focus position is set
+ * closer to the camera
+ */
+static int dw9714_resume(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct v4l2_subdev *sd = i2c_get_clientdata(client);
+	struct dw9714_device *dw9714_dev = container_of(sd,
+							struct dw9714_device,
+							sd);
+	int ret, val;
+
+	dev_dbg(dev, "%s\n", __func__);
+
+	for (val = dw9714_dev->current_val % DW9714_CTRL_STEPS;
+	     val < dw9714_dev->current_val + DW9714_CTRL_STEPS - 1;
+	     val += DW9714_CTRL_STEPS) {
+		ret = dw9714_i2c_write(client,
+				       DW9714_VAL((u16) val, DW9714_DEFAULT_S));
+		if (ret)
+			dev_err(dev, "%s I2C failure: %d", __func__, ret);
+		usleep_range(DW9714_CTRL_DELAY_US, DW9714_CTRL_DELAY_US + 10);
+	}
+
+	/* restore v4l2 control values */
+	ret = v4l2_ctrl_handler_setup(&dw9714_dev->ctrls_vcm);
+	dev_dbg(dev, "%s ret = %d\n", __func__, ret);
+	return ret;
+}
+
+#else
+
+#define dw9714_suspend	NULL
+#define dw9714_resume	NULL
+#define dw9714_runtime_suspend	NULL
+#define dw9714_runtime_resume	NULL
+
+#endif /* CONFIG_PM */
+
+#ifdef CONFIG_ACPI
+static const struct acpi_device_id dw9714_acpi_match[] = {
+	{"DW9714", 0},
+	{},
+};
+MODULE_DEVICE_TABLE(acpi, dw9714_acpi_match);
+#endif
+
+static const struct i2c_device_id dw9714_id_table[] = {
+	{DW9714_NAME, 0},
+	{}
+};
+
+MODULE_DEVICE_TABLE(i2c, dw9714_id_table);
+
+static const struct dev_pm_ops dw9714_pm_ops = {
+	.suspend = dw9714_suspend,
+	.resume = dw9714_resume,
+	.runtime_suspend = dw9714_runtime_suspend,
+	.runtime_resume = dw9714_runtime_resume,
+};
+
+static struct i2c_driver dw9714_i2c_driver = {
+	.driver = {
+		.name = DW9714_NAME,
+		.pm = &dw9714_pm_ops,
+#ifdef CONFIG_ACPI
+		.acpi_match_table = ACPI_PTR(dw9714_acpi_match),
+#endif
+	},
+	.probe = dw9714_probe,
+	.remove = dw9714_remove,
+	.id_table = dw9714_id_table,
+};
+
+module_i2c_driver(dw9714_i2c_driver);
+
+MODULE_AUTHOR("Tianshu Qiu <tian.shu.qiu@intel.com>");
+MODULE_AUTHOR("Jian Xu Zheng <jian.xu.zheng@intel.com>");
+MODULE_AUTHOR("Yuning Pu <yuning.pu@intel.com>");
+MODULE_AUTHOR("Jouni Ukkonen <jouni.ukkonen@intel.com>");
+MODULE_AUTHOR("Tommi Franttila <tommi.franttila@intel.com>");
+MODULE_DESCRIPTION("DW9714 VCM driver");
+MODULE_LICENSE("GPL");
-- 
1.9.1