This patch makes the internal encoder implementation of the simple
KMS helpers available to drivers.
These simple-encoder helpers initialize an encoder with an empty
implementation. This covers the requirements of most of the existing
DRM drivers. A call to drm_simple_encoder_create() allocates and
initializes an encoder instance, a call to drm_simple_encoder_init()
initializes a pre-allocated instance.
v3:
* remove drm_simple_encoder_create(); not required yet
* provide more precise documentation
v2:
* move simple encoder to KMS helpers
* remove name argument; simplifies implementation
* don't allocate with devm_ interfaces; unsafe with DRM
Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
Reviewed-by: Sam Ravnborg <sam@xxxxxxxxxxxx>
---
drivers/gpu/drm/drm_simple_kms_helper.c | 34 ++++++++++++++++++++++---
include/drm/drm_simple_kms_helper.h | 4 +++
2 files changed, 35 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/drm_simple_kms_helper.c b/drivers/gpu/drm/drm_simple_kms_helper.c
index 15fb516ae2d8..04309e4660de 100644
--- a/drivers/gpu/drm/drm_simple_kms_helper.c
+++ b/drivers/gpu/drm/drm_simple_kms_helper.c
@@ -26,12 +26,41 @@
* entity. Some flexibility for code reuse is provided through a separately
* allocated &drm_connector object and supporting optional &drm_bridge
* encoder drivers.
+ *
+ * Many drivers require only a very simple encoder that fulfills the minimum
+ * requirements of the display pipeline and does not add additional
+ * functionality. The function drm_simple_encoder_init() provides an
+ * implementation of such an encoder.
*/
-static const struct drm_encoder_funcs drm_simple_kms_encoder_funcs = {
+static const struct drm_encoder_funcs drm_simple_encoder_funcs_cleanup = {
.destroy = drm_encoder_cleanup,
};
+/**
+ * drm_simple_encoder_init - Initialize a preallocated encoder
+ * @dev: drm device
+ * @funcs: callbacks for this encoder
+ * @encoder_type: user visible type of the encoder
+ *
+ * Initialises a preallocated encoder that has no further functionality.
+ * Settings for possible CRTC and clones are left to their initial values.
+ * The encoder will be cleaned up automatically as part of the mode-setting
+ * cleanup.
+ *
+ * Returns:
+ * Zero on success, error code on failure.
+ */
+int drm_simple_encoder_init(struct drm_device *dev,
+ struct drm_encoder *encoder,
+ int encoder_type)
+{
+ return drm_encoder_init(dev, encoder,
+ &drm_simple_encoder_funcs_cleanup,
+ encoder_type, NULL);
+}
+EXPORT_SYMBOL(drm_simple_encoder_init);
+
static enum drm_mode_status
drm_simple_kms_crtc_mode_valid(struct drm_crtc *crtc,
const struct drm_display_mode *mode)
@@ -288,8 +317,7 @@ int drm_simple_display_pipe_init(struct drm_device *dev,
return ret;
encoder->possible_crtcs = drm_crtc_mask(crtc);
- ret = drm_encoder_init(dev, encoder, &drm_simple_kms_encoder_funcs,
- DRM_MODE_ENCODER_NONE, NULL);
+ ret = drm_simple_encoder_init(dev, encoder, DRM_MODE_ENCODER_NONE);
if (ret || !connector)
return ret;
diff --git a/include/drm/drm_simple_kms_helper.h b/include/drm/drm_simple_kms_helper.h
index e253ba7bea9d..a026375464ff 100644
--- a/include/drm/drm_simple_kms_helper.h
+++ b/include/drm/drm_simple_kms_helper.h
@@ -181,4 +181,8 @@ int drm_simple_display_pipe_init(struct drm_device *dev,
const uint64_t *format_modifiers,
struct drm_connector *connector);
+int drm_simple_encoder_init(struct drm_device *dev,
+ struct drm_encoder *encoder,
+ int encoder_type);
+
#endif /* __LINUX_DRM_SIMPLE_KMS_HELPER_H */
--
2.25.0
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