--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * AD5398 DAC driver for camera voice coil focus.
+ * Copyright (C) 2021 Raspberry Pi (Trading) Ltd.
+ *
+ * Based on AD5820 DAC driver by Nokia and TI.
+ *
+ * This driver uses the regulator framework notification hooks on the
+ * assumption that the VCM and sensor share a regulator. This means the VCM
+ * position will be restored when either the sensor or VCM subdevices are opened
+ * or powered up. The client can therefore choose to ignore the VCM subdevice,
+ * and the lens position will be as previously requested. Without that, there
+ * is a hard requirement to have the VCM subdevice open in order for the VCM
+ * to be powered and at the requested position.
+ */
+
+#include <linux/errno.h>
+#include <linux/i2c.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/regulator/consumer.h>
+#include <linux/gpio/consumer.h>
+
+#include <media/v4l2-ctrls.h>
+#include <media/v4l2-device.h>
+#include <media/v4l2-subdev.h>
+
+/* Register definitions */
+#define AD5398_POWER_DOWN BIT(15)
+#define AD5398_DAC_SHIFT 4
+
+#define to_ad5398_device(sd) container_of(sd, struct ad5398_device, subdev)
+
+struct ad5398_device {
+ struct v4l2_subdev subdev;
+ struct ad5398_platform_data *platform_data;
+ struct regulator *vana;
+ struct notifier_block nb;
+
+ struct v4l2_ctrl_handler ctrls;
+ u32 focus_absolute;
+
+ bool standby;
+};
+
+static int ad5398_write(struct ad5398_device *coil, u16 data)
+{
+ struct i2c_client *client = v4l2_get_subdevdata(&coil->subdev);
+ struct i2c_msg msg;
+ __be16 be_data;
+ int r;
+
+ if (!client->adapter)
+ return -ENODEV;
+
+ be_data = cpu_to_be16(data);
+ msg.addr = client->addr;
+ msg.flags = 0;
+ msg.len = 2;
+ msg.buf = (u8 *)&be_data;
+
+ r = i2c_transfer(client->adapter, &msg, 1);
+ if (r < 0) {
+ dev_err(&client->dev, "write failed, error %d\n", r);
+ return r;
+ }
+
+ return 0;
+}
+
+/*
+ * 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 ad5398_update_hw(struct ad5398_device *coil)
+{
+ u16 status;
+
+ status = coil->focus_absolute << AD5398_DAC_SHIFT;
+
+ if (coil->standby)
+ status |= AD5398_POWER_DOWN;
+
+ return ad5398_write(coil, status);
+}
+
+/*
+ * Power handling
+ */
+static int ad5398_power_off(struct ad5398_device *coil)
+{
+ int ret = 0;
+
+ coil->standby = true;
+ ret = ad5398_update_hw(coil);
+
+ return ret;
+}
+
+static int ad5398_power_on(struct ad5398_device *coil)
+{
+ int ret;
+
+ /* Restore the hardware settings. */
+ coil->standby = false;
+ ret = ad5398_update_hw(coil);
+ if (ret)
+ goto fail;
+
+ return 0;
+
+fail:
+ coil->standby = true;
+
+ return ret;
+}
+
+/*
+ * V4L2 controls
+ */
+static int ad5398_set_ctrl(struct v4l2_ctrl *ctrl)
+{
+ struct ad5398_device *coil =
+ container_of(ctrl->handler, struct ad5398_device, ctrls);
+
+ switch (ctrl->id) {
+ case V4L2_CID_FOCUS_ABSOLUTE:
+ coil->focus_absolute = ctrl->val;
+ return ad5398_update_hw(coil);
+ }
+
+ return 0;
+}
+
+static const struct v4l2_ctrl_ops ad5398_ctrl_ops = {
+ .s_ctrl = ad5398_set_ctrl,
+};
+
+static int ad5398_init_controls(struct ad5398_device *coil)
+{
+ v4l2_ctrl_handler_init(&coil->ctrls, 1);
+
+ /*
+ * V4L2_CID_FOCUS_ABSOLUTE
+ *
+ * Minimum current is 0 mA, maximum is 120 mA. Thus, 1 code is
+ * equivalent to 120/1023 = 0.1173 mA. Nevertheless, we do not use [mA]
+ * for focus position, because it is meaningless for user. Meaningful
+ * would be to use focus distance or even its inverse, but since the
+ * driver doesn't have sufficient knowledge to do the conversion, we
+ * will just use abstract codes here. In any case, smaller value = focus
+ * position farther from camera. The default zero value means focus at
+ * infinity, and also least current consumption.
+ */
+ v4l2_ctrl_new_std(&coil->ctrls, &ad5398_ctrl_ops,
+ V4L2_CID_FOCUS_ABSOLUTE, 0, 1023, 1, 0);
+
+ if (coil->ctrls.error)
+ return coil->ctrls.error;
+
+ coil->focus_absolute = 0;
+
+ coil->subdev.ctrl_handler = &coil->ctrls;
+
+ return 0;
+}
+
+/*
+ * V4L2 subdev operations
+ */
+static int ad5398_registered(struct v4l2_subdev *subdev)
+{
+ struct ad5398_device *coil = to_ad5398_device(subdev);
+
+ return ad5398_init_controls(coil);
+}
+
+static int
+ad5398_set_power(struct v4l2_subdev *subdev, int on)
+{
+ struct ad5398_device *coil = to_ad5398_device(subdev);
+ int ret;
+
+ if (on)
+ ret = regulator_enable(coil->vana);
+ else
+ ret = regulator_disable(coil->vana);
+
+ return ret;
+}
+
+static int ad5398_open(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
+{
+ struct ad5398_device *coil = to_ad5398_device(sd);
+
+ return regulator_enable(coil->vana);
+}
+
+static int ad5398_close(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
+{
+ struct ad5398_device *coil = to_ad5398_device(sd);
+
+ return regulator_disable(coil->vana);
+}
+
+static const struct v4l2_subdev_core_ops ad5398_core_ops = {
+ .s_power = ad5398_set_power,
+};
+
+static const struct v4l2_subdev_ops ad5398_ops = {
+ .core = &ad5398_core_ops,
+};
+
+static const struct v4l2_subdev_internal_ops ad5398_internal_ops = {
+ .registered = ad5398_registered,
+ .open = ad5398_open,
+ .close = ad5398_close,
+};
+
+/*
+ * I2C driver
+ */
+static int __maybe_unused ad5398_suspend(struct device *dev)
+{
+ struct i2c_client *client = container_of(dev, struct i2c_client, dev);
+ struct v4l2_subdev *subdev = i2c_get_clientdata(client);
+ struct ad5398_device *coil = to_ad5398_device(subdev);
+
+ return regulator_enable(coil->vana);
+}
+
+static int __maybe_unused ad5398_resume(struct device *dev)
+{
+ struct i2c_client *client = container_of(dev, struct i2c_client, dev);
+ struct v4l2_subdev *subdev = i2c_get_clientdata(client);
+ struct ad5398_device *coil = to_ad5398_device(subdev);
+
+ return regulator_disable(coil->vana);
+}
+
+static int ad5398_regulator_notifier(struct notifier_block *nb,
+ unsigned long event,
+ void *ignored)
+{
+ struct ad5398_device *coil = container_of(nb, struct ad5398_device, nb);
+
+ if (event == REGULATOR_EVENT_ENABLE)
+ ad5398_power_on(coil);
+ else if (event == REGULATOR_EVENT_PRE_DISABLE)
+ ad5398_power_off(coil);
+
+ return NOTIFY_OK;
+}
+
+static int ad5398_probe(struct i2c_client *client,
+ const struct i2c_device_id *devid)
+{
+ struct ad5398_device *coil;
+ int ret;
+
+ coil = devm_kzalloc(&client->dev, sizeof(*coil), GFP_KERNEL);
+ if (!coil)
+ return -ENOMEM;
+
+ coil->vana = devm_regulator_get(&client->dev, "VANA");
+ if (IS_ERR(coil->vana)) {
+ ret = PTR_ERR(coil->vana);
+ if (ret != -EPROBE_DEFER)
+ dev_err(&client->dev, "could not get regulator for vana\n");
+ return ret;
+ }
+
+ v4l2_i2c_subdev_init(&coil->subdev, client, &ad5398_ops);
+ coil->subdev.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
+ coil->subdev.internal_ops = &ad5398_internal_ops;
+ coil->subdev.entity.function = MEDIA_ENT_F_LENS;
+ strscpy(coil->subdev.name, "ad5398 focus", sizeof(coil->subdev.name));
+
+ coil->nb.notifier_call = &ad5398_regulator_notifier;
+ ret = regulator_register_notifier(coil->vana, &coil->nb);
+ if (ret < 0)
+ return ret;
+
+ ret = media_entity_pads_init(&coil->subdev.entity, 0, NULL);
+ if (ret < 0)
+ goto cleanup2;
+
+ ret = v4l2_async_register_subdev(&coil->subdev);
+ if (ret < 0)
+ goto cleanup;
+
+ return ret;
+
+cleanup:
+ media_entity_cleanup(&coil->subdev.entity);
+cleanup2:
+ regulator_unregister_notifier(coil->vana, &coil->nb);
+ return ret;
+}
+
+static int ad5398_remove(struct i2c_client *client)
+{
+ struct v4l2_subdev *subdev = i2c_get_clientdata(client);
+ struct ad5398_device *coil = to_ad5398_device(subdev);
+
+ v4l2_async_unregister_subdev(&coil->subdev);
+ v4l2_ctrl_handler_free(&coil->ctrls);
+ media_entity_cleanup(&coil->subdev.entity);
+ return 0;
+}
+
+static const struct i2c_device_id ad5398_id_table[] = {
+ { "ad5398", 0 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, ad5398_id_table);
+
+static const struct of_device_id ad5398_of_table[] = {
+ { .compatible = "adi,ad5398" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, ad5398_of_table);
+
+static SIMPLE_DEV_PM_OPS(ad5398_pm, ad5398_suspend, ad5398_resume);
+
+static struct i2c_driver ad5398_i2c_driver = {
+ .driver = {
+ .name = "ad5398",
+ .pm = &ad5398_pm,
+ .of_match_table = ad5398_of_table,
+ },
+ .probe = ad5398_probe,
+ .remove = ad5398_remove,
+ .id_table = ad5398_id_table,
+};
+
+module_i2c_driver(ad5398_i2c_driver);
+
+MODULE_AUTHOR("Dave Stevenson <dave.stevenson@raspberrypi.com>");
+MODULE_DESCRIPTION("AD5398 camera lens driver");
+MODULE_LICENSE("GPL");
projects / platform / kernel / linux-rpi.git / commitdiff