drm: Decouple EDID parsing from I2C adapter

[platform/adaptation/renesas_rcar/renesas_kernel.git] / drivers / gpu / drm / drm_edid.c

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index b924306..246cba4 100644 (file)
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -1106,9 +1106,9 @@ EXPORT_SYMBOL(drm_edid_is_valid);
  * Try to fetch EDID information by calling i2c driver function.
  */
 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;
@@ -1164,8 +1164,26 @@ 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)
+/**
+ * drm_do_get_edid - get EDID data using a custom EDID block read function
+ * @connector: connector we're probing
+ * @get_edid_block: EDID block read function
+ * @data: private data passed to the block read function
+ *
+ * When the I2C adapter connected to the DDC bus is hidden behind a device that
+ * exposes a different interface to read EDID blocks this function can be used
+ * to get EDID data using a custom block read function.
+ *
+ * As in the general case the DDC bus is accessible by the kernel at the I2C
+ * level, drivers must make all reasonable efforts to expose it as an I2C
+ * adapter and use drm_get_edid() instead of abusing this function.
+ *
+ * Return: Pointer to valid EDID or NULL if we couldn't find any.
+ */
+struct edid *drm_do_get_edid(struct drm_connector *connector,
+       int (*get_edid_block)(void *data, u8 *buf, unsigned int block,
+                             size_t len),
+       void *data)
 {
        int i, j = 0, valid_extensions = 0;
        u8 *block, *new;
@@ -1176,7 +1194,7 @@ 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;
@@ -1190,7 +1208,7 @@ 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)
@@ -1199,7 +1217,7 @@ 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;
@@ -1227,7 +1245,7 @@ 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) {
@@ -1240,6 +1258,7 @@ out:
        kfree(block);
        return NULL;
 }
+EXPORT_SYMBOL_GPL(drm_do_get_edid);
 
 /**
  * Probe DDC presence.
@@ -1269,12 +1288,10 @@ 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);