On Wed, 2007-02-21 at 21:23 +0000, James Simmons wrote:
> This is the new display intreface. Its goal is to provide a standard
> interface to various types of displays. Currently we have auxdisplay,
> output acpi device and the now defunct lcd class in the backlight directory.
> Please apply.
Is this an attempt to consolidate all display hardware and drivers?
>
[snip]
> +struct class *display_class;
> +EXPORT_SYMBOL(display_class);
> +static int index;
> +
> +struct display_device *display_device_register(struct display_driver *driver,
> + struct device *dev, void
> *devdata)
> +{
> + struct display_device *new_dev = NULL;
> + int ret = -EINVAL;
> +
> + if (unlikely(!driver))
> + return ERR_PTR(ret);
> +
> + new_dev = kzalloc(sizeof(struct display_device), GFP_KERNEL);
> + if (likely(new_dev) && unlikely(driver->probe(new_dev, devdata))) {
> + new_dev->dev = device_create(display_class, dev, 0,
> + "display%d", index);
> +
> + if (!IS_ERR(new_dev->dev)) {
> + dev_set_drvdata(new_dev->dev, new_dev);
> + new_dev->driver = driver;
> + new_dev->parent = dev;
> + mutex_init(&new_dev->lock);
> + index++;
> + } else {
> + new_dev->dev = NULL;
> + kfree(new_dev);
Set new_dev to NULL on failure.
> + }
> + }
> + return new_dev;
> +}
> +EXPORT_SYMBOL(display_device_register);
> +
> +void display_device_unregister(struct display_device *ddev)
> +{
> + if (!ddev)
> + return;
> + mutex_lock(&ddev->lock);
> + device_del(ddev->dev);
> + ddev->driver = NULL;
> + index--;
display0
display1
index = 2
unregister display0
index = 1
display_device_register() as device1
device1 <-- BUG, already used.
[snip]
> +
> +struct display_device;
> +
> +/* This structure defines all the properties of a Display. */
> +struct display_driver {
> + int (*set_contrast)(struct display_device *, unsigned int);
> + int (*get_contrast)(struct display_device *);
> + void (*suspend)(struct display_device *, pm_message_t state);
> + void (*resume)(struct display_device *);
> + int (*probe)(struct display_device *, void *);
> + int (*remove)(struct display_device *);
> + int max_contrast;
If this is an attempt to consolidate, I don't see the 'brightness'
hook of backlight and lcd.
If this is not a consolidation, why don't we just extend the lcd class?
Tony
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