Den 12.02.2019 15.06, skrev Daniel Vetter:
> On Sun, Feb 10, 2019 at 02:10:30PM +0100, Noralf Trønnes wrote:
>> Add driver example that shows how devm_drm_dev_init() can be used.
>>
>> Signed-off-by: Noralf Trønnes <noralf@xxxxxxxxxxx>
>> ---
>>
>> I'm not sure how detailed such an example such be and a description of
>> some kind is also required. Help is needed :-)
>
> Personally I'd make it more minimal, pseudo-code style, removing most of
> the boilerplate (e.g. the container_of wrapper). That way it can highlight
> the important bits more. But it's already very minimal.
>
> Wrt text, maybe a minimal intro paragraph. Aside from that looks all good
> to me.
>
> Acked-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
>
> One question below.
>>
>> Noralf.
>>
>> drivers/gpu/drm/drm_drv.c | 118 ++++++++++++++++++++++++++++++++++++++
>> 1 file changed, 118 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
>> index 351f128ec4b7..99ca3551688f 100644
>> --- a/drivers/gpu/drm/drm_drv.c
>> +++ b/drivers/gpu/drm/drm_drv.c
>> @@ -286,6 +286,124 @@ void drm_minor_release(struct drm_minor *minor)
>> * Note that the lifetime rules for &drm_device instance has still a lot of
>> * historical baggage. Hence use the reference counting provided by
>> * drm_dev_get() and drm_dev_put() only carefully.
>> + *
>> + * Display driver example
>> + * ~~~~~~~~~~~~~~~~~~~~~~
>> + *
>> + * .. code-block:: c
>> + *
>> + * struct driver_device {
>> + * struct drm_device drm;
>> + * void *userspace_facing;
>> + * struct clk *pclk;
>> + * };
>> + *
>> + * static inline struct driver_device *drm_to_priv(struct drm_device *drm)
>> + * {
>> + * return container_of(drm, struct driver_device, drm);
>> + * }
>> + *
>> + * static void driver_drm_release(struct drm_device *drm)
>> + * {
>> + * struct driver_device *priv = drm_to_priv(drm);
>> + *
>> + * drm_mode_config_cleanup(drm);
>> + * drm_dev_fini(drm);
>> + * kfree(priv->userspace_facing);
>> + * kfree(priv);
>> + * }
>> + *
>> + * static struct drm_driver driver_drm_driver = {
>> + * [...]
>> + * .release = driver_drm_release,
>> + * };
>> + *
>> + * static int driver_probe(struct platform_device *pdev)
>> + * {
>> + * struct driver_device *priv;
>> + * struct drm_device *drm;
>> + * int ret;
>> + *
>> + * priv = kzalloc(sizeof(*priv), GFP_KERNEL);
>> + * if (!priv)
>> + * return -ENOMEM;
>> + *
>> + * drm = &priv->drm;
>> + *
>> + * ret = devm_drm_dev_init(&pdev->dev, drm, &driver_drm_driver);
>> + * if (ret) {
>> + * kfree(drm);
>> + * return ret;
>> + * }
>> + *
>> + * drm_mode_config_init(drm);
>> + *
>> + * priv->userspace_facing = kzalloc(..., GFP_KERNEL);
>> + * if (!priv->userspace_facing)
>> + * return -ENOMEM;
>> + *
>> + * priv->pclk = devm_clk_get(dev, "PCLK");
>> + * if (IS_ERR(priv->pclk))
>> + * return PTR_ERR(priv->pclk);
>> + *
>> + * [ Further setup, display pipeline etc ]
>> + *
>> + * drm_mode_config_reset(drm);
>> + *
>> + * ret = drm_dev_register(drm);
>> + * if (ret)
>> + * return ret;
>> + *
>> + * platform_set_drvdata(pdev, drm);
>
> Hm, don't we need to set that before registering? Or even before
> drm_mode_config_reset? Kinda depends upon what the driver is using the
> drvdata for.
>
Yeah, it depends. I can move up though, it doesn't hurt, since drvdata
is cleared by the driver core if probe fails.
Noralf.
>> + *
>> + * drm_fbdev_generic_setup(drm, 32);
>> + *
>> + * return 0;
>> + * }
>> + *
>> + * [ This function is called before the devm_ resources are released ]
>> + * static int driver_remove(struct platform_device *pdev)
>> + * {
>> + * struct drm_device *drm = platform_get_drvdata(pdev);
>> + *
>> + * drm_dev_unregister(drm);
>> + * drm_atomic_helper_shutdown(drm)
>> + *
>> + * return 0;
>> + * }
>> + *
>> + * static void driver_shutdown(struct platform_device *pdev)
>> + * {
>> + * drm_atomic_helper_shutdown(platform_get_drvdata(pdev));
>> + * }
>> + *
>> + * static int __maybe_unused driver_pm_suspend(struct device *dev)
>> + * {
>> + * return drm_mode_config_helper_suspend(dev_get_drvdata(dev));
>> + * }
>> + *
>> + * static int __maybe_unused driver_pm_resume(struct device *dev)
>> + * {
>> + * drm_mode_config_helper_resume(dev_get_drvdata(dev));
>> + *
>> + * return 0;
>> + * }
>> + *
>> + * static const struct dev_pm_ops driver_pm_ops = {
>> + * SET_SYSTEM_SLEEP_PM_OPS(driver_pm_suspend, driver_pm_resume)
>> + * };
>> + *
>> + * static struct platform_driver driver_driver = {
>> + * .driver = {
>> + * [...]
>> + * .pm = &driver_pm_ops,
>> + * },
>> + * .probe = driver_probe,
>> + * .remove = driver_remove,
>> + * .shutdown = driver_shutdown,
>> + * };
>> + * module_platform_driver(driver_driver);
>> + *
>> */
>>
>> /**
>> --
>> 2.20.1
>>
>
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