From: Alan Chiang <alanx.chi...@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....@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
since v4:
- sent patchset included DT binding with cover page
since v6:
- change the return code of i2c_check
- fix long cols exceed 80 chars
- remove #define DW9807_NAME since only used once

 MAINTAINERS                |   7 +
 drivers/media/i2c/Kconfig  |  10 ++
 drivers/media/i2c/Makefile |   1 +
 drivers/media/i2c/dw9807.c | 335 +++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 353 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.ai...@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" <j...@vanzandt.mv.com>
 L:     blinux-l...@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..062c30f
--- /dev/null
+++ b/drivers/media/i2c/dw9807.c
@@ -0,0 +1,335 @@
+// 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 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;
+       int ret;
+
+       ret = i2c_master_send(client, (const char *)&status_addr,
+               sizeof(status_addr));
+       if (ret < 0) {
+               dev_err(&client->dev, "I2C write STATUS address fail ret = 
%d\n",
+                       ret);
+               return ret;
+       }
+
+       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 ret;
+       }
+
+       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 ((ret = dw9807_i2c_check(client)) != 0) {
+               if (ret < 0)
+                       return ret;
+
+               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)) {
+               if (ret < 0) {
+                       dev_err(&client->dev,
+                               "I2C write MSB fail ret=%d\n", ret);
+                       return ret;
+               } else {
+                       dev_err(&client->dev, "I2C write MSB fail, transmission 
size is not equal the size expected\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)
+               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",
+               .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.chi...@intel.com>");
+MODULE_DESCRIPTION("DW9807 VCM driver");
+MODULE_LICENSE("GPL v2");
-- 
2.7.4

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