Re: [PATCH/RFC v3 5/5] media: Add registration helpers for V4L2 flash sub-devices
From: Jacek Anaszewski
Date: Thu Apr 17 2014 - 04:28:05 EST
Hi Sakari,
Thanks for the review.
On 04/16/2014 08:21 PM, Sakari Ailus wrote:
Hi Jacek,
Thanks for the update!
[...]
+static inline enum led_brightness v4l2_flash_intensity_to_led_brightness(
+ struct led_ctrl *config,
+ u32 intensity)
Fits on a single line.
+{
+ return intensity / config->step;
Shouldn't you first decrement the minimum before the division?
Brightness level 0 means that led is off. Let's consider following case:
intensity - 15625
config->step - 15625
intensity / config->step = 1 (the lowest possible current level)
+}
+
+static inline u32 v4l2_flash_led_brightness_to_intensity(
+ struct led_ctrl *config,
+ enum led_brightness brightness)
+{
+ return brightness * config->step;
And do the opposite here?
+}
+
+static int v4l2_flash_g_volatile_ctrl(struct v4l2_ctrl *c)
+
+{
+ struct v4l2_flash *v4l2_flash = v4l2_ctrl_to_v4l2_flash(c);
+ struct led_classdev *led_cdev = v4l2_flash->led_cdev;
+ struct led_flash *flash = led_cdev->flash;
+ struct v4l2_flash_ctrl *ctrl = &v4l2_flash->ctrl;
+ u32 fault;
+ int ret;
+
+ switch (c->id) {
+ case V4L2_CID_FLASH_TORCH_INTENSITY:
+ if (ctrl->led_mode->val == V4L2_FLASH_LED_MODE_TORCH) {
+ ret = v4l2_call_flash_op(brightness_update, led_cdev);
+ if (ret < 0)
+ return ret;
+ ctrl->torch_intensity->val =
+ v4l2_flash_led_brightness_to_intensity(
+ &led_cdev->brightness_ctrl,
+ led_cdev->brightness);
+ }
+ return 0;
+ case V4L2_CID_FLASH_INTENSITY:
+ ret = v4l2_call_flash_op(flash_brightness_update, led_cdev);
+ if (ret < 0)
+ return ret;
+ /* no conversion is needed */
+ c->val = flash->brightness.val;
+ return 0;
+ case V4L2_CID_FLASH_INDICATOR_INTENSITY:
+ ret = v4l2_call_flash_op(indicator_brightness_update, led_cdev);
+ if (ret < 0)
+ return ret;
+ /* no conversion is needed */
+ c->val = flash->indicator_brightness->val;
+ return 0;
+ case V4L2_CID_FLASH_STROBE_STATUS:
+ ret = v4l2_call_flash_op(strobe_get, led_cdev);
+ if (ret < 0)
+ return ret;
+ c->val = !!ret;
+ return 0;
+ case V4L2_CID_FLASH_FAULT:
+ /* led faults map directly to V4L2 flash faults */
+ ret = v4l2_call_flash_op(fault_get, led_cdev, &fault);
+ if (!ret)
The return value seems to come all the way from regmap_read() and the bus
related implementatio. I would just consider negative values errors, as
above.
I think that ret would be returned if it wasn't equal to 0. But indeed
it should be done the same way as for the other cases.
+ c->val = fault;
+ return ret;
+ default:
+ return -EINVAL;
+ }
+}
+
+static int v4l2_flash_s_ctrl(struct v4l2_ctrl *c)
+{
+ struct v4l2_flash *v4l2_flash = v4l2_ctrl_to_v4l2_flash(c);
+ struct led_classdev *led_cdev = v4l2_flash->led_cdev;
+ struct v4l2_flash_ctrl *ctrl = &v4l2_flash->ctrl;
+ enum led_brightness torch_brightness;
+ bool external_strobe;
+ int ret;
+
+ switch (c->id) {
+ case V4L2_CID_FLASH_LED_MODE:
+ switch (c->val) {
+ case V4L2_FLASH_LED_MODE_NONE:
+ v4l2_call_flash_op(brightness_set, led_cdev, 0);
+ return v4l2_call_flash_op(strobe_set, led_cdev, false);
+ case V4L2_FLASH_LED_MODE_FLASH:
+ /* Turn off torch LED */
+ v4l2_call_flash_op(brightness_set, led_cdev, 0);
+ external_strobe = (ctrl->source->val ==
+ V4L2_FLASH_STROBE_SOURCE_EXTERNAL);
+ return v4l2_call_flash_op(external_strobe_set, led_cdev,
+ external_strobe);
+ case V4L2_FLASH_LED_MODE_TORCH:
+ /* Stop flash strobing */
+ ret = v4l2_call_flash_op(strobe_set, led_cdev, false);
+ if (ret)
+ return ret;
+ /* torch is always triggered by software */
+ ret = v4l2_call_flash_op(external_strobe_set, led_cdev,
+ false);
Does the LED API not assume this at the moment? I'm not saying it should,
though. :-)
Actually strobe source should apply only to flash leds. I will
remove this call.
+ if (ret)
+ return ret;
+
+ torch_brightness =
+ v4l2_flash_intensity_to_led_brightness(
+ &led_cdev->brightness_ctrl,
+ ctrl->torch_intensity->val);
+ v4l2_call_flash_op(brightness_set, led_cdev,
+ torch_brightness);
+ return ret;
+ }
+ break;
+ case V4L2_CID_FLASH_STROBE_SOURCE:
+ return v4l2_call_flash_op(external_strobe_set, led_cdev,
+ c->val == V4L2_FLASH_STROBE_SOURCE_EXTERNAL);
+ case V4L2_CID_FLASH_STROBE:
+ if (ctrl->led_mode->val != V4L2_FLASH_LED_MODE_FLASH ||
+ ctrl->source->val != V4L2_FLASH_STROBE_SOURCE_SOFTWARE)
I vote for -EBUSY instead.
I agree.
+ return -EINVAL;
+ return v4l2_call_flash_op(strobe_set, led_cdev, true);
+ case V4L2_CID_FLASH_STROBE_STOP:
+ return v4l2_call_flash_op(strobe_set, led_cdev, false);
+ case V4L2_CID_FLASH_TIMEOUT:
+ ret = v4l2_call_flash_op(timeout_set, led_cdev, c->val);
+ case V4L2_CID_FLASH_INTENSITY:
+ /* no conversion is needed */
+ return v4l2_call_flash_op(flash_brightness_set, led_cdev,
+ c->val);
+ case V4L2_CID_FLASH_INDICATOR_INTENSITY:
+ /* no conversion is needed */
+ return v4l2_call_flash_op(indicator_brightness_set, led_cdev,
+ c->val);
+ case V4L2_CID_FLASH_TORCH_INTENSITY:
+ if (ctrl->led_mode->val == V4L2_FLASH_LED_MODE_TORCH) {
+ torch_brightness =
+ v4l2_flash_intensity_to_led_brightness(
+ &led_cdev->brightness_ctrl,
+ ctrl->torch_intensity->val);
+ v4l2_call_flash_op(brightness_set, led_cdev,
+ torch_brightness);
I could be missing something but don't torch and indicator require similar
handling?
Why? Torch units need conversion whereas indicator units don't.
Moreover they have different LED API.
+ }
+ return 0;
+ }
+
+ return -EINVAL;
+}
+
+static const struct v4l2_ctrl_ops v4l2_flash_ctrl_ops = {
+ .g_volatile_ctrl = v4l2_flash_g_volatile_ctrl,
+ .s_ctrl = v4l2_flash_s_ctrl,
+};
+
+static int v4l2_flash_init_controls(struct v4l2_flash *v4l2_flash)
+
+{
+ struct led_classdev *led_cdev = v4l2_flash->led_cdev;
+ struct led_flash *flash = led_cdev->flash;
+ bool has_indicator = flash->indicator_brightness;
+ struct v4l2_ctrl *ctrl;
+ struct led_ctrl *ctrl_cfg;
+ unsigned int mask;
+ int ret, max, num_ctrls;
+
+ num_ctrls = flash->has_flash_led ? 8 : 2;
+ if (flash->fault_flags)
+ ++num_ctrls;
+ if (has_indicator)
+ ++num_ctrls;
+
+ v4l2_ctrl_handler_init(&v4l2_flash->hdl, num_ctrls);
+
+ mask = 1 << V4L2_FLASH_LED_MODE_NONE |
+ 1 << V4L2_FLASH_LED_MODE_TORCH;
+ if (flash->has_flash_led)
+ mask |= 1 << V4L2_FLASH_LED_MODE_FLASH;
+
+ /* Configure FLASH_LED_MODE ctrl */
+ v4l2_flash->ctrl.led_mode = v4l2_ctrl_new_std_menu(
+ &v4l2_flash->hdl,
+ &v4l2_flash_ctrl_ops, V4L2_CID_FLASH_LED_MODE,
+ V4L2_FLASH_LED_MODE_TORCH, ~mask,
+ V4L2_FLASH_LED_MODE_NONE);
+
+ /* Configure TORCH_INTENSITY ctrl */
+ ctrl_cfg = &led_cdev->brightness_ctrl;
+ ctrl = v4l2_ctrl_new_std(&v4l2_flash->hdl, &v4l2_flash_ctrl_ops,
+ V4L2_CID_FLASH_TORCH_INTENSITY,
+ ctrl_cfg->min, ctrl_cfg->max,
+ ctrl_cfg->step, ctrl_cfg->val);
+ if (ctrl)
+ ctrl->flags |= V4L2_CTRL_FLAG_VOLATILE;
+ v4l2_flash->ctrl.torch_intensity = ctrl;
+
+ if (flash->has_flash_led) {
+ /* Configure FLASH_STROBE_SOURCE ctrl */
+ mask = 1 << V4L2_FLASH_STROBE_SOURCE_SOFTWARE;
+
+ if (flash->has_external_strobe) {
+ mask |= 1 << V4L2_FLASH_STROBE_SOURCE_EXTERNAL;
+ max = V4L2_FLASH_STROBE_SOURCE_EXTERNAL;
+ } else {
+ max = V4L2_FLASH_STROBE_SOURCE_SOFTWARE;
+ }
+
+ v4l2_flash->ctrl.source = v4l2_ctrl_new_std_menu(
+ &v4l2_flash->hdl,
+ &v4l2_flash_ctrl_ops,
+ V4L2_CID_FLASH_STROBE_SOURCE,
+ max,
+ ~mask,
+ V4L2_FLASH_STROBE_SOURCE_SOFTWARE);
+
+ /* Configure FLASH_STROBE ctrl */
+ ctrl = v4l2_ctrl_new_std(&v4l2_flash->hdl, &v4l2_flash_ctrl_ops,
+ V4L2_CID_FLASH_STROBE, 0, 1, 1, 0);
+
+ /* Configure FLASH_STROBE_STOP ctrl */
+ ctrl = v4l2_ctrl_new_std(&v4l2_flash->hdl, &v4l2_flash_ctrl_ops,
+ V4L2_CID_FLASH_STROBE_STOP,
+ 0, 1, 1, 0);
+
+ /* Configure FLASH_STROBE_STATUS ctrl */
+ ctrl = v4l2_ctrl_new_std(&v4l2_flash->hdl, &v4l2_flash_ctrl_ops,
+ V4L2_CID_FLASH_STROBE_STATUS,
+ 0, 1, 1, 1);
+ if (ctrl)
+ ctrl->flags |= V4L2_CTRL_FLAG_VOLATILE |
+ V4L2_CTRL_FLAG_READ_ONLY;
+
+ /* Configure FLASH_TIMEOUT ctrl */
+ ctrl_cfg = &flash->timeout;
+ ctrl = v4l2_ctrl_new_std(&v4l2_flash->hdl, &v4l2_flash_ctrl_ops,
+ V4L2_CID_FLASH_TIMEOUT, ctrl_cfg->min,
+ ctrl_cfg->max, ctrl_cfg->step,
+ ctrl_cfg->val);
+ if (ctrl)
+ ctrl->flags |= V4L2_CTRL_FLAG_VOLATILE;
+
+ /* Configure FLASH_INTENSITY ctrl */
+ ctrl_cfg = &flash->brightness;
+ ctrl = v4l2_ctrl_new_std(&v4l2_flash->hdl, &v4l2_flash_ctrl_ops,
+ V4L2_CID_FLASH_INTENSITY,
+ ctrl_cfg->min, ctrl_cfg->max,
+ ctrl_cfg->step, ctrl_cfg->val);
+ if (ctrl)
+ ctrl->flags |= V4L2_CTRL_FLAG_VOLATILE;
+
+ if (flash->fault_flags) {
+ /* Configure FLASH_FAULT ctrl */
+ ctrl = v4l2_ctrl_new_std(&v4l2_flash->hdl,
+ &v4l2_flash_ctrl_ops,
+ V4L2_CID_FLASH_FAULT, 0,
+ flash->fault_flags,
+ 0, 0);
+ if (ctrl)
+ ctrl->flags |= V4L2_CTRL_FLAG_VOLATILE |
+ V4L2_CTRL_FLAG_READ_ONLY;
+ }
+ if (has_indicator) {
In theory it's possible to have an indicator without the flash. So I'd keep
the two independent.
OK.
+ /* Configure FLASH_INDICATOR_INTENSITY ctrl */
+ ctrl_cfg = flash->indicator_brightness;
+ ctrl = v4l2_ctrl_new_std(
+ &v4l2_flash->hdl, &v4l2_flash_ctrl_ops,
+ V4L2_CID_FLASH_INDICATOR_INTENSITY,
+ ctrl_cfg->min, ctrl_cfg->max,
+ ctrl_cfg->step, ctrl_cfg->val);
+ if (ctrl)
+ ctrl->flags |= V4L2_CTRL_FLAG_VOLATILE;
+ }
+ }
+
+ if (v4l2_flash->hdl.error) {
+ ret = v4l2_flash->hdl.error;
+ goto error_free;
+ }
+
+ ret = v4l2_ctrl_handler_setup(&v4l2_flash->hdl);
+ if (ret < 0)
+ goto error_free;
+
+ v4l2_flash->subdev.ctrl_handler = &v4l2_flash->hdl;
+
+ return 0;
+
+error_free:
+ v4l2_ctrl_handler_free(&v4l2_flash->hdl);
+ return ret;
+}
+
+/*
+ * V4L2 subdev internal operations
+ */
+
+static int v4l2_flash_open(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
+{
+ struct v4l2_flash *v4l2_flash = v4l2_subdev_to_v4l2_flash(sd);
+ struct led_classdev *led_cdev = v4l2_flash->led_cdev;
+
+ mutex_lock(&led_cdev->led_lock);
+ v4l2_call_flash_op(sysfs_lock, led_cdev);
Have you thought about device power management yet?
Having in mind that the V4L2 Flash sub-device is only a wrapper
for LED driver, shouldn't power management be left to the
drivers?
Traditionally, the existing flash controller drivers are powered when a file
handle is opened. Many newer implementations seem to consume so little power
that it's not worthwhile to try to power them off.
Binding the power state to open file handles isn't very generic either but
it's very simple and works.
V4L2 sub-devices do not use runtime PM as of yet, so perhaps this could be
left for later.
+ mutex_unlock(&led_cdev->led_lock);
+
+ return 0;
+}
+
+static int v4l2_flash_close(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
+{
+ struct v4l2_flash *v4l2_flash = v4l2_subdev_to_v4l2_flash(sd);
+ struct led_classdev *led_cdev = v4l2_flash->led_cdev;
+
+ mutex_lock(&led_cdev->led_lock);
+ v4l2_call_flash_op(sysfs_unlock, led_cdev);
+ mutex_unlock(&led_cdev->led_lock);
+
+ return 0;
+}
+
+static const struct v4l2_subdev_internal_ops v4l2_flash_subdev_internal_ops = {
+ .open = v4l2_flash_open,
+ .close = v4l2_flash_close,
+};
+
+static struct v4l2_subdev_ops v4l2_flash_subdev_ops = {
+};
+
+int v4l2_flash_init(struct led_classdev *led_cdev,
+ const struct v4l2_flash_ops *ops)
+{
+ struct v4l2_flash *flash = &led_cdev->flash->v4l2_flash;
+ struct v4l2_subdev *sd = &flash->subdev;
+ int ret;
+
+ if (!led_cdev || !ops)
+ return -EINVAL;
+
+ flash->led_cdev = led_cdev;
+ sd->dev = led_cdev->dev->parent;
+ v4l2_subdev_init(sd, &v4l2_flash_subdev_ops);
+ sd->internal_ops = &v4l2_flash_subdev_internal_ops;
+ sd->flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
+ snprintf(sd->name, sizeof(sd->name), led_cdev->name);
It'd be nice to have the bus address in the name as well. But that would
belong to the driver which calls v4l2_flash_init(). The existing flash
controller drivers probably don't do this but many sensor drivers already
do. The name is expected to be unique in the media device.
Will cover this.
+ flash->ops = ops;
+
+ ret = v4l2_flash_init_controls(flash);
+ if (ret < 0)
+ goto err_init_controls;
+
+ ret = media_entity_init(&sd->entity, 0, NULL, 0);
+ if (ret < 0)
+ goto err_init_entity;
+
+ sd->entity.type = MEDIA_ENT_T_V4L2_SUBDEV_FLASH;
+
+ ret = v4l2_async_register_subdev(sd);
+ if (ret < 0)
+ goto err_init_entity;
+
+ return 0;
+
+err_init_entity:
+ media_entity_cleanup(&sd->entity);
+err_init_controls:
+ v4l2_ctrl_handler_free(sd->ctrl_handler);
+ return -EINVAL;
+}
+EXPORT_SYMBOL_GPL(v4l2_flash_init);
+
+void v4l2_flash_release(struct led_classdev *led_cdev)
+{
+ struct v4l2_flash *flash = &led_cdev->flash->v4l2_flash;
+
+ v4l2_ctrl_handler_free(flash->subdev.ctrl_handler);
+ v4l2_async_unregister_subdev(&flash->subdev);
+ media_entity_cleanup(&flash->subdev.entity);
+}
+EXPORT_SYMBOL_GPL(v4l2_flash_release);
diff --git a/include/media/v4l2-flash.h b/include/media/v4l2-flash.h
new file mode 100644
index 0000000..fe16ddd
--- /dev/null
+++ b/include/media/v4l2-flash.h
@@ -0,0 +1,119 @@
+/*
+ * V4L2 Flash LED sub-device registration helpers.
+ *
+ * Copyright (C) 2014 Samsung Electronics Co., Ltd
+ * Author: Jacek Anaszewski <j.anaszewski@xxxxxxxxxxx>
+ *
+ * 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."
+ */
+
+#ifndef _V4L2_FLASH_H
+#define _V4L2_FLASH_H
+
+#include <media/v4l2-ctrls.h>
+#include <media/v4l2-device.h>
+#include <media/v4l2-dev.h>
+#include <media/v4l2-event.h>
+#include <media/v4l2-ioctl.h>
+
+#define v4l2_call_flash_op(op, args...) \
+ ((v4l2_flash)->ops->op(args)) \
Extra backslash above.
I don't think you should assume the caller will have a local variable called
v4l2_flash. :-)
I assumed that as this macro is only for the module internal use
and aim at simplifying the calling code it can be implemented that way.
But when I look at it now it indeed doesn't seem reasonable.
+struct led_classdev;
+enum led_brightness;
+
+struct v4l2_flash_ops {
+ void (*brightness_set)(struct led_classdev *led_cdev,
+ enum led_brightness brightness);
+ int (*brightness_update)(struct led_classdev *led_cdev);
+ int (*flash_brightness_set)(struct led_classdev *led_cdev,
+ u32 brightness);
+ int (*flash_brightness_update)(struct led_classdev *led_cdev);
+ int (*strobe_set)(struct led_classdev *led_cdev,
+ bool state);
+ int (*strobe_get)(struct led_classdev *led_cdev);
+ int (*timeout_set)(struct led_classdev *led_cdev,
+ u32 timeout);
+ int (*indicator_brightness_set)(struct led_classdev *led_cdev,
+ u32 brightness);
+ int (*indicator_brightness_update)(struct led_classdev *led_cdev);
+ int (*external_strobe_set)(struct led_classdev *led_cdev,
+ bool enable);
+ int (*fault_get)(struct led_classdev *led_cdev,
+ u32 *fault);
+ void (*sysfs_lock)(struct led_classdev *led_cdev);
+ void (*sysfs_unlock)(struct led_classdev *led_cdev);
+};
+
+/**
+ * struct v4l2_flash_ctrl - controls that define the sub-dev's state
+ * @source: V4L2_CID_FLASH_STROBE_SOURCE control
+ * @led_mode: V4L2_CID_FLASH_LED_MODE control
+ * @torch_intensity: V4L2_CID_FLASH_TORCH_INTENSITY control
+ */
+struct v4l2_flash_ctrl {
+ struct v4l2_ctrl *source;
+ struct v4l2_ctrl *led_mode;
+ struct v4l2_ctrl *torch_intensity;
+};
+
+/**
+ * struct v4l2_flash - Flash sub-device context
+ * @led_cdev: LED class device controlled by this sub-device
+ * @ops: LED class device ops
+ * @subdev: V4L2 sub-device
+ * @hdl: flash controls handler
+ * @ctrl: state defining controls
+ */
+struct v4l2_flash {
+ struct led_classdev *led_cdev;
+ const struct v4l2_flash_ops *ops;
+
+ struct v4l2_subdev subdev;
+ struct v4l2_ctrl_handler hdl;
+ struct v4l2_flash_ctrl ctrl;
+};
+
+static inline struct v4l2_flash *v4l2_subdev_to_v4l2_flash(struct v4l2_subdev *sd)
Over 80 characters per line.
+{
+ return container_of(sd, struct v4l2_flash, subdev);
+}
+
+static inline struct v4l2_flash *v4l2_ctrl_to_v4l2_flash(struct v4l2_ctrl *c)
+{
+ return container_of(c->handler, struct v4l2_flash, hdl);
+}
+
+#ifdef CONFIG_V4L2_FLASH
+/**
+ * v4l2_flash_init - initialize V4L2 flash led sub-device
+ * @led_cdev: the LED to create subdev upon
+ * @ops: LED subsystem callbacks
+ *
+ * Create V4L2 subdev wrapping given LED subsystem device.
+ */
+int v4l2_flash_init(struct led_classdev *led_cdev,
+ const struct v4l2_flash_ops *ops);
+
+/**
+ * v4l2_flash_release - release V4L2 flash led sub-device
+ * @flash: a structure representing V4L2 flash led device
+ *
+ * Release V4L2 flash led subdev.
+ */
+void v4l2_flash_release(struct led_classdev *led_cdev);
+#else
+static inline int v4l2_flash_init(struct led_classdev *led_cdev,
+ const struct v4l2_flash_ops *ops)
+{
+ return 0;
+}
+
+static inline void v4l2_flash_release(struct led_classdev *led_cdev)
+{
+}
Could you put the two to the first patch? It won't compile otherwise.
Yeah. I didn't make test build after every patch :-/.
+#endif /* CONFIG_V4L2_FLASH */
+
+#endif /* _V4L2_FLASH_H */
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