[PATCH 09/12] drm: Decouple EDID parsing from I2C adapter

[Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>]

From: Lars-Peter Clausen <lars@metafoo.de>

The drm_get_edid() function performs direct I2C accesses to read EDID
blocks, assuming that the monitor DDC interface is directly connected to
the I2C bus. It can't thus be used with HDMI encoders that control the
DDC bus and expose EDID blocks through a different interface.

Refactor drm_do_get_edid() to take a block read callback function
instead of an I2C adapter, and export it for direct use by drivers.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
---
 drivers/gpu/drm/drm_edid.c | 26 +++++++++++++-------------
 include/drm/drm_edid.h     |  4 ++++
 2 files changed, 17 insertions(+), 13 deletions(-)

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 1bdbfd0..c98958c 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -1125,9 +1125,9 @@ EXPORT_SYMBOL(drm_edid_is_valid);
  * Return: 0 on success or -1 on failure.
  */
 static int
-drm_do_probe_ddc_edid(struct i2c_adapter *adapter, unsigned char *buf,
-		      int block, int len)
+drm_do_probe_ddc_edid(void *data, u8 *buf, unsigned int block, size_t len)
 {
+	struct i2c_adapter *adapter = data;
 	unsigned char start = block * EDID_LENGTH;
 	unsigned char segment = block >> 1;
 	unsigned char xfers = segment ? 3 : 2;
@@ -1184,8 +1184,9 @@ static bool drm_edid_is_zero(u8 *in_edid, int length)
 	return true;
 }
 
-static u8 *
-drm_do_get_edid(struct drm_connector *connector, struct i2c_adapter *adapter)
+struct edid *drm_do_get_edid(struct drm_connector *connector,
+	int (*get_edid_block)(void *, u8 *buf, unsigned int, size_t),
+	void *data)
 {
 	int i, j = 0, valid_extensions = 0;
 	u8 *block, *new;
@@ -1196,7 +1197,7 @@ drm_do_get_edid(struct drm_connector *connector, struct i2c_adapter *adapter)
 
 	/* base block fetch */
 	for (i = 0; i < 4; i++) {
-		if (drm_do_probe_ddc_edid(adapter, block, 0, EDID_LENGTH))
+		if (get_edid_block(data, block, 0, EDID_LENGTH))
 			goto out;
 		if (drm_edid_block_valid(block, 0, print_bad_edid))
 			break;
@@ -1210,7 +1211,7 @@ drm_do_get_edid(struct drm_connector *connector, struct i2c_adapter *adapter)
 
 	/* if there's no extensions, we're done */
 	if (block[0x7e] = 0)
-		return block;
+		return (struct edid *)block;
 
 	new = krealloc(block, (block[0x7e] + 1) * EDID_LENGTH, GFP_KERNEL);
 	if (!new)
@@ -1219,7 +1220,7 @@ drm_do_get_edid(struct drm_connector *connector, struct i2c_adapter *adapter)
 
 	for (j = 1; j <= block[0x7e]; j++) {
 		for (i = 0; i < 4; i++) {
-			if (drm_do_probe_ddc_edid(adapter,
+			if (get_edid_block(data,
 				  block + (valid_extensions + 1) * EDID_LENGTH,
 				  j, EDID_LENGTH))
 				goto out;
@@ -1247,7 +1248,7 @@ drm_do_get_edid(struct drm_connector *connector, struct i2c_adapter *adapter)
 		block = new;
 	}
 
-	return block;
+	return (struct edid *)block;
 
 carp:
 	if (print_bad_edid) {
@@ -1260,6 +1261,7 @@ out:
 	kfree(block);
 	return NULL;
 }
+EXPORT_SYMBOL_GPL(drm_do_get_edid);
 
 /**
  * drm_probe_ddc() - probe DDC presence
@@ -1289,12 +1291,10 @@ EXPORT_SYMBOL(drm_probe_ddc);
 struct edid *drm_get_edid(struct drm_connector *connector,
 			  struct i2c_adapter *adapter)
 {
-	struct edid *edid = NULL;
-
-	if (drm_probe_ddc(adapter))
-		edid = (struct edid *)drm_do_get_edid(connector, adapter);
+	if (!drm_probe_ddc(adapter))
+		return NULL;
 
-	return edid;
+	return drm_do_get_edid(connector, drm_do_probe_ddc_edid, adapter);
 }
 EXPORT_SYMBOL(drm_get_edid);
 
diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h
index b96031d..bcf05ef 100644
--- a/include/drm/drm_edid.h
+++ b/include/drm/drm_edid.h
@@ -279,4 +279,8 @@ int
 drm_hdmi_vendor_infoframe_from_display_mode(struct hdmi_vendor_infoframe *frame,
 					    const struct drm_display_mode *mode);
 
+struct edid *drm_do_get_edid(struct drm_connector *connector,
+	int (*get_edid_block)(void *, u8 *buf, unsigned int, size_t),
+	void *data);
+
 #endif /* __DRM_EDID_H__ */
-- 
1.8.5.5