[PATCH 1/7] drm/edid: Implement drm_probe_ddc() with drm_edid_probe_custom()

[Thomas Zimmermann <tzimmermann@xxxxxxx>]

Move the logic from drm_probe_ddc() into drm_edid_probe_custom(),
which receives the EDID read function as argument. Allows drivers
without DDC to implement similar functionality without duplicating
the code.

Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
---
 drivers/gpu/drm/drm_edid.c | 22 +++++++++++++++++++---
 include/drm/drm_edid.h     |  3 +++
 2 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index ea77577a37864..a3e9333f9177a 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -2608,6 +2608,24 @@ void drm_edid_free(const struct drm_edid *drm_edid)
 }
 EXPORT_SYMBOL(drm_edid_free);
 
+/**
+ * drm_edid_probe_custom() - probe DDC presence
+ * @read_block: EDID block read function
+ * @context: Private data passed to the block read function
+ *
+ * Probes for EDID data. Only reads enough data to detect the presence
+ * of the EDID channel.
+ *
+ * Return: True on success, false on failure.
+ */
+bool drm_edid_probe_custom(read_block_fn read_block, void *context)
+{
+	unsigned char out;
+
+	return (read_block(context, &out, 0, 1) == 0);
+}
+EXPORT_SYMBOL(drm_edid_probe_custom);
+
 /**
  * drm_probe_ddc() - probe DDC presence
  * @adapter: I2C adapter to probe
@@ -2617,9 +2635,7 @@ EXPORT_SYMBOL(drm_edid_free);
 bool
 drm_probe_ddc(struct i2c_adapter *adapter)
 {
-	unsigned char out;
-
-	return (drm_do_probe_ddc_edid(adapter, &out, 0, 1) == 0);
+	return drm_edid_probe_custom(drm_do_probe_ddc_edid, adapter);
 }
 EXPORT_SYMBOL(drm_probe_ddc);
 
diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h
index 6f65bbf655a1f..4d1797ade5f1d 100644
--- a/include/drm/drm_edid.h
+++ b/include/drm/drm_edid.h
@@ -410,6 +410,9 @@ static inline void drm_edid_decode_panel_id(u32 panel_id, char vend[4], u16 *pro
 	drm_edid_decode_mfg_id(panel_id >> 16, vend);
 }
 
+bool
+drm_edid_probe_custom(int (*read_block)(void *context, u8 *buf, unsigned int block, size_t len),
+		      void *context);
 bool drm_probe_ddc(struct i2c_adapter *adapter);
 struct edid *drm_do_get_edid(struct drm_connector *connector,
 	int (*get_edid_block)(void *data, u8 *buf, unsigned int block,
-- 
2.44.0