1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (c) 2007 Intel Corporation
4  *
5  * Authers: Jesse Barnes <jesse.barnes@intel.com>
6  */
7 
8 #include <linux/i2c.h>
9 
10 #include <drm/drm_edid.h>
11 
12 #include "psb_intel_drv.h"
13 
14 /**
15  * psb_intel_ddc_probe
16  * @adapter:   Associated I2C adaptor
17  */
18 bool psb_intel_ddc_probe(struct i2c_adapter *adapter)
19 {
20 	u8 out_buf[] = { 0x0, 0x0 };
21 	u8 buf[2];
22 	int ret;
23 	struct i2c_msg msgs[] = {
24 		{
25 		 .addr = 0x50,
26 		 .flags = 0,
27 		 .len = 1,
28 		 .buf = out_buf,
29 		 },
30 		{
31 		 .addr = 0x50,
32 		 .flags = I2C_M_RD,
33 		 .len = 1,
34 		 .buf = buf,
35 		 }
36 	};
37 
38 	ret = i2c_transfer(adapter, msgs, 2);
39 	if (ret == 2)
40 		return true;
41 
42 	return false;
43 }
44 
45 /**
46  * psb_intel_ddc_get_modes - get modelist from monitor
47  * @connector: DRM connector device to use
48  * @adapter:   Associated I2C adaptor
49  *
50  * Fetch the EDID information from @connector using the DDC bus.
51  */
52 int psb_intel_ddc_get_modes(struct drm_connector *connector,
53 			    struct i2c_adapter *adapter)
54 {
55 	struct edid *edid;
56 	int ret = 0;
57 
58 	edid = drm_get_edid(connector, adapter);
59 	if (edid) {
60 		drm_connector_update_edid_property(connector, edid);
61 		ret = drm_add_edid_modes(connector, edid);
62 		kfree(edid);
63 	}
64 	return ret;
65 }
66