[V5, 2/2] media: i2c: dw9768: Add DW9768 VCM driver

[Dongchun Zhu <dongchun.zhu@mediatek.com>]

Add a V4L2 sub-device driver for DW9768 voice coil motor, providing
control to set the desired focus via IIC serial interface.

Signed-off-by: Dongchun Zhu <dongchun.zhu@mediatek.com>
---
 MAINTAINERS                |   1 +
 drivers/media/i2c/Kconfig  |  11 ++
 drivers/media/i2c/Makefile |   1 +
 drivers/media/i2c/dw9768.c | 440 +++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 453 insertions(+)
 create mode 100644 drivers/media/i2c/dw9768.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 8d72c41..c92dc99 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -5157,6 +5157,7 @@ L:	linux-media@vger.kernel.org
 S:	Maintained
 T:	git git://linuxtv.org/media_tree.git
 F:	Documentation/devicetree/bindings/media/i2c/dongwoon,dw9768.yaml
+F:	drivers/media/i2c/dw9768.c
 
 DONGWOON DW9807 LENS VOICE COIL DRIVER
 M:	Sakari Ailus <sakari.ailus@linux.intel.com>
diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
index 125d596..6a3f9da 100644
--- a/drivers/media/i2c/Kconfig
+++ b/drivers/media/i2c/Kconfig
@@ -1040,6 +1040,17 @@ 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
+	depends on PM
+	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 77bf7d0..4057476 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..dd68534
--- /dev/null
+++ b/drivers/media/i2c/dw9768.c
@@ -0,0 +1,440 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2020 MediaTek Inc.
+
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/pm_runtime.h>
+#include <linux/regulator/consumer.h>
+#include <media/v4l2-async.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			(1024 - 1)
+/*
+ * 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
+
+/*
+ * Ring control and Power control register
+ * Bit[1] RING_EN
+ * 0: Direct mode
+ * 1: AAC mode (ringing control mode)
+ * Bit[0] PD
+ * 0: Normal operation mode
+ * 1: Power down mode
+ * DW9768 requires waiting time of Topr after PD reset takes place.
+ */
+#define DW9768_RING_PD_CONTROL_REG		0x02
+#define DW9768_PD_MODE_OFF			0x00
+#define DW9768_PD_MODE_EN			BIT(0)
+#define DW9768_AAC_MODE_EN			BIT(1)
+
+/*
+ * DW9768 separates two registers to control the VCM position.
+ * One for MSB value, another is LSB value.
+ * DAC_MSB: D[9:8] (ADD: 0x03)
+ * DAC_LSB: D[7:0] (ADD: 0x04)
+ * D[9:0] DAC data input: positive output current = D[9:0] / 1023 * 100[mA]
+ */
+#define DW9768_MSB_ADDR				0x03
+#define DW9768_LSB_ADDR				0x04
+#define DW9768_STATUS_ADDR			0x05
+
+/*
+ * AAC mode control & prescale register
+ * Bit[7:5] Namely AC[2:0], decide the VCM mode and operation time.
+ * 000 Direct(default)
+ * 001 AAC2 0.48xTvib
+ * 010 AAC3 0.70xTvib
+ * 011 AAC4 0.75xTvib
+ * 100 Reserved
+ * 101 AAC8 1.13xTvib
+ * 110 Reserved
+ * 111 Reserved
+ * Bit[2:0] Namely PRESC[2:0], set the internal clock dividing rate as follow.
+ * 000 2
+ * 001 1(default)
+ * 010 1/2
+ * 011 1/4
+ * 100 8
+ * 101 4
+ * 110 Reserved
+ * 111 Reserved
+ */
+#define DW9768_AAC_PRESC_REG			0x06
+#define DW9768_AAC3_SELECT_DIVIDING_RATE_1	0x41
+
+/*
+ * VCM period of vibration register
+ * Bit[5:0] Defined as VCM rising periodic time (Tvib) together with PRESC[2:0]
+ * Tvib = (6.3ms + AACT[5:0] * 0.1ms) * Dividing Rate
+ * Dividing Rate is the internal clock dividing rate that is defined at
+ * PRESCALE register (ADD: 0x06)
+ */
+#define DW9768_AAC_TIME_REG			0x07
+#define DW9768_AACT_CNT				0x39
+
+/*
+ * DW9768 requires waiting time (delay time) of t_OPR after power-up,
+ * or in the case of PD reset taking place.
+ */
+#define DW9768_T_OPR_US				1000
+
+/*
+ * 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 DW9768_MOVE_STEPS			16
+
+/*
+ * DW9768_AAC_PRESC_REG & DW9768_AAC_TIME_REG determine VCM operation time.
+ * If DW9768_AAC_PRESC_REG is 0x41, and DW9768_AAC_TIME_REG is 0x39, VCM mode
+ * would be AAC3, Operation Time would be 0.70xTvib, that is 8.40ms.
+ */
+#define DW9768_MOVE_DELAY_US			8400
+#define DW9768_STABLE_TIME_US			20000
+
+static const char * const dw9768_supply_names[] = {
+	"vin",	/* I2C I/O interface power */
+	"vdd",	/* VCM power */
+};
+
+/* dw9768 device structure */
+struct dw9768 {
+	struct regulator_bulk_data supplies[ARRAY_SIZE(dw9768_supply_names)];
+	struct v4l2_ctrl_handler ctrls;
+	struct v4l2_ctrl *focus;
+	struct v4l2_subdev sd;
+};
+
+static inline struct dw9768 *to_dw9768(struct v4l2_ctrl *ctrl)
+{
+	return container_of(ctrl->handler, struct dw9768, ctrls);
+}
+
+static inline struct dw9768 *sd_to_dw9768(struct v4l2_subdev *subdev)
+{
+	return container_of(subdev, struct dw9768, sd);
+}
+
+struct regval_list {
+	u8 reg_num;
+	u8 value;
+};
+
+static const struct regval_list dw9768_init_regs[] = {
+	{DW9768_RING_PD_CONTROL_REG, DW9768_AAC_MODE_EN},
+	{DW9768_AAC_PRESC_REG, DW9768_AAC3_SELECT_DIVIDING_RATE_1},
+	{DW9768_AAC_TIME_REG, DW9768_AACT_CNT},
+};
+
+static int dw9768_write_array(struct dw9768 *dw9768,
+			      const struct regval_list *vals, size_t len)
+{
+	struct i2c_client *client = v4l2_get_subdevdata(&dw9768->sd);
+	unsigned int i;
+	int ret;
+
+	for (i = 0; i < len; i++) {
+		ret = i2c_smbus_write_byte_data(client, vals[i].reg_num,
+						vals[i].value);
+		if (ret < 0)
+			return ret;
+	}
+	return 0;
+}
+
+static int dw9768_set_dac(struct dw9768 *dw9768, u16 val)
+{
+	struct i2c_client *client = v4l2_get_subdevdata(&dw9768->sd);
+
+	/* Write VCM position to registers */
+	return i2c_smbus_write_word_swapped(client, DW9768_MSB_ADDR, val);
+}
+
+static int dw9768_init(struct dw9768 *dw9768)
+{
+	struct i2c_client *client = v4l2_get_subdevdata(&dw9768->sd);
+	int ret, val;
+
+	/* Reset DW9768_RING_PD_CONTROL_REG to default status 0x00 */
+	ret = i2c_smbus_write_byte_data(client, DW9768_RING_PD_CONTROL_REG,
+					DW9768_PD_MODE_OFF);
+	if (ret < 0)
+		return ret;
+
+	/*
+	 * DW9769 requires waiting delay time of t_OPR
+	 * after PD reset takes place.
+	 */
+	usleep_range(DW9768_T_OPR_US, DW9768_T_OPR_US + 100);
+
+	ret = dw9768_write_array(dw9768, dw9768_init_regs,
+				 ARRAY_SIZE(dw9768_init_regs));
+	if (ret)
+		return ret;
+
+	for (val = dw9768->focus->val % DW9768_MOVE_STEPS;
+	     val <= dw9768->focus->val;
+	     val += DW9768_MOVE_STEPS) {
+		ret = dw9768_set_dac(dw9768, val);
+		if (ret) {
+			dev_err(&client->dev, "%s I2C failure: %d",
+				__func__, ret);
+			return ret;
+		}
+		usleep_range(DW9768_MOVE_DELAY_US,
+			     DW9768_MOVE_DELAY_US + 1000);
+	}
+
+	return 0;
+}
+
+static int dw9768_release(struct dw9768 *dw9768)
+{
+	struct i2c_client *client = v4l2_get_subdevdata(&dw9768->sd);
+	int ret, val;
+
+	val = round_down(dw9768->focus->val, DW9768_MOVE_STEPS);
+	for ( ; val >= 0; val -= DW9768_MOVE_STEPS) {
+		ret = dw9768_set_dac(dw9768, val);
+		if (ret) {
+			dev_err(&client->dev, "I2C write fail: %d", ret);
+			return ret;
+		}
+		usleep_range(DW9768_MOVE_DELAY_US, DW9768_MOVE_DELAY_US + 1000);
+	}
+
+	/*
+	 * Wait for the motor to stabilize after the last movement
+	 * to prevent the motor from shaking.
+	 */
+	usleep_range(DW9768_STABLE_TIME_US - DW9768_MOVE_DELAY_US,
+		     DW9768_STABLE_TIME_US - DW9768_MOVE_DELAY_US + 1000);
+
+	ret = i2c_smbus_write_byte_data(client, DW9768_RING_PD_CONTROL_REG,
+					DW9768_PD_MODE_EN);
+	if (ret < 0)
+		return ret;
+
+	/*
+	 * DW9769 requires waiting delay time of t_OPR
+	 * after PD reset takes place.
+	 */
+	usleep_range(DW9768_T_OPR_US, DW9768_T_OPR_US + 100);
+
+	return 0;
+}
+
+static int __maybe_unused dw9768_runtime_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(sd);
+
+	dw9768_release(dw9768);
+	regulator_bulk_disable(ARRAY_SIZE(dw9768_supply_names),
+			       dw9768->supplies);
+
+	return 0;
+}
+
+static int __maybe_unused dw9768_runtime_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(sd);
+	int ret;
+
+	ret = regulator_bulk_enable(ARRAY_SIZE(dw9768_supply_names),
+				    dw9768->supplies);
+	if (ret < 0) {
+		dev_err(dev, "failed to enable regulators\n");
+		return ret;
+	}
+
+	/*
+	 * The datasheet refers to t_OPR that needs to be waited before sending
+	 * I2C commands after power-up.
+	 */
+	usleep_range(DW9768_T_OPR_US, DW9768_T_OPR_US + 100);
+
+	ret = dw9768_init(dw9768);
+	if (ret < 0)
+		goto disable_regulator;
+
+	return 0;
+
+disable_regulator:
+	regulator_bulk_disable(ARRAY_SIZE(dw9768_supply_names),
+			       dw9768->supplies);
+
+	return ret;
+}
+
+static int dw9768_set_ctrl(struct v4l2_ctrl *ctrl)
+{
+	struct dw9768 *dw9768 = to_dw9768(ctrl);
+
+	if (ctrl->id == V4L2_CID_FOCUS_ABSOLUTE)
+		return dw9768_set_dac(dw9768, ctrl->val);
+
+	return 0;
+}
+
+static const struct v4l2_ctrl_ops dw9768_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 int dw9768_init_controls(struct dw9768 *dw9768)
+{
+	struct v4l2_ctrl_handler *hdl = &dw9768->ctrls;
+	const struct v4l2_ctrl_ops *ops = &dw9768_ctrl_ops;
+
+	v4l2_ctrl_handler_init(hdl, 1);
+
+	dw9768->focus = 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;
+	unsigned int i;
+	int ret;
+
+	dw9768 = devm_kzalloc(dev, sizeof(*dw9768), GFP_KERNEL);
+	if (!dw9768)
+		return -ENOMEM;
+
+	v4l2_i2c_subdev_init(&dw9768->sd, client, &dw9768_ops);
+
+	for (i = 0; i < ARRAY_SIZE(dw9768_supply_names); i++)
+		dw9768->supplies[i].supply = dw9768_supply_names[i];
+
+	ret = devm_regulator_bulk_get(dev, ARRAY_SIZE(dw9768_supply_names),
+				      dw9768->supplies);
+	if (ret) {
+		dev_err(dev, "failed to get regulators\n");
+		return ret;
+	}
+
+	ret = dw9768_init_controls(dw9768);
+	if (ret)
+		goto entity_cleanup;
+
+	dw9768->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
+	dw9768->sd.internal_ops = &dw9768_int_ops;
+
+	ret = media_entity_pads_init(&dw9768->sd.entity, 0, NULL);
+	if (ret < 0)
+		goto entity_cleanup;
+
+	dw9768->sd.entity.function = MEDIA_ENT_F_LENS;
+
+	pm_runtime_enable(dev);
+	if (!pm_runtime_enabled(dev)) {
+		ret = dw9768_runtime_resume(dev);
+		if (ret < 0) {
+			dev_err(dev, "failed to power on: %d\n", ret);
+			goto entity_cleanup;
+		}
+	}
+
+	ret = v4l2_async_register_subdev(&dw9768->sd);
+	if (ret < 0)
+		goto entity_cleanup;
+
+	return 0;
+
+entity_cleanup:
+	v4l2_ctrl_handler_free(&dw9768->ctrls);
+	media_entity_cleanup(&dw9768->sd.entity);
+	return ret;
+}
+
+static int dw9768_remove(struct i2c_client *client)
+{
+	struct v4l2_subdev *sd = i2c_get_clientdata(client);
+	struct dw9768 *dw9768 = sd_to_dw9768(sd);
+
+	pm_runtime_disable(&client->dev);
+	v4l2_async_unregister_subdev(&dw9768->sd);
+	v4l2_ctrl_handler_free(&dw9768->ctrls);
+	media_entity_cleanup(&dw9768->sd.entity);
+	if (!pm_runtime_status_suspended(&client->dev))
+		dw9768_runtime_suspend(&client->dev);
+	pm_runtime_set_suspended(&client->dev);
+
+	return 0;
+}
+
+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_runtime_suspend, dw9768_runtime_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,
+};
+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