On Sun, Feb 23, 2020 at 6:43 PM Noralf Trønnes noralf@tronnes.org wrote:
Den 17.02.2020 10.38, skrev Daniel Vetter:
On Sun, Feb 16, 2020 at 06:21:16PM +0100, Noralf Trønnes wrote:
drm_client_init_from_id() provides a way for clients to add a client based on the minor. drm_client_modeset_set() provides a way to set the modeset for clients that handles connectors and display mode on their own.
Signed-off-by: Noralf Trønnes noralf@tronnes.org
drivers/gpu/drm/drm_client.c | 37 ++++++++++++++++++++ drivers/gpu/drm/drm_client_modeset.c | 52 ++++++++++++++++++++++++++++ include/drm/drm_client.h | 4 +++ 3 files changed, 93 insertions(+)
diff --git a/drivers/gpu/drm/drm_client.c b/drivers/gpu/drm/drm_client.c index d9a2e3695525..dbd73fe8d987 100644 --- a/drivers/gpu/drm/drm_client.c +++ b/drivers/gpu/drm/drm_client.c @@ -112,6 +112,43 @@ int drm_client_init(struct drm_device *dev, struct drm_client_dev *client, } EXPORT_SYMBOL(drm_client_init);
+/**
- drm_client_init_from_id - Initialise a DRM client
- @minor_id: DRM minor id
- @client: DRM client
- @name: Client name
- @funcs: DRM client functions (optional)
- This function looks up the drm_device using the minor id and initializes the client.
- It also registeres the client to avoid a possible race with DRM device unregister.
I think another sentence here would be good, explaining that this is for drivers outside of drm to expose a specific drm driver in some fashion, and just outright mention your use-case as an example.
I'm also not sure whether lookup-by-minor is the greatest thing for kernel-internal lookups like this, maybe Greg has some idea?
What alternatives do you see? Parent device name?
I did a scan to see what others are doing, and most have a consumer name lookup on the struct device (Device Tree or lookup tables):
I think those are all for other purposes. What we want here is that some interface things binds to something else. I was thinking sysfs paths to the underlying struct device (i.e. the one in drm_device->dev) might be neater, since that's more unique. Using minors we get that entire trouble of having duplicates (and in the past triplicatres) due to our uapi-flavors. But in sysfs there's only one underlying device.
Anyway if there's no precedence and Greg doesn't have ideas either then I guess we can just go with minor ids. It's about as good as anything else really. -Daniel
struct reset_control *__reset_control_get(struct device *dev, const char *id, int index, bool shared, bool optional, bool acquired);
struct iio_channel *iio_channel_get(struct device *dev, const char *consumer_channel);
struct regulator *__must_check regulator_get(struct device *dev, const char *id);
struct pwm_device *pwm_get(struct device *dev, const char *con_id)
struct gpio_desc *__must_check gpiod_get(struct device *dev, const char *con_id, enum gpiod_flags flags);
SPI and I2C use the bus index as lookup:
extern struct i2c_adapter *i2c_get_adapter(int nr);
extern struct spi_controller *spi_busnum_to_master(u16 busnum);
Noralf.
- See drm_client_init() and drm_client_register().
- Returns:
- Zero on success or negative error code on failure.
- */
+int drm_client_init_from_id(unsigned int minor_id, struct drm_client_dev *client,
const char *name, const struct drm_client_funcs *funcs)+{
- struct drm_minor *minor;
- int ret;
- minor = drm_minor_acquire(minor_id);
- if (IS_ERR(minor))
return PTR_ERR(minor);- mutex_lock(&minor->dev->clientlist_mutex);
- ret = drm_client_init(minor->dev, client, name, funcs);
- if (!ret)
list_add(&client->list, &minor->dev->clientlist);- mutex_unlock(&minor->dev->clientlist_mutex);
- drm_minor_release(minor);
- return ret;
+} +EXPORT_SYMBOL(drm_client_init_from_id);
/**
- drm_client_register - Register client
- @client: DRM client