1 /*
2  * Copyright (C) 2014 Traphandler
3  * Copyright (C) 2014 Free Electrons
4  * Copyright (C) 2014 Atmel
5  *
6  * Author: Jean-Jacques Hiblot <jjhiblot@traphandler.com>
7  * Author: Boris BREZILLON <boris.brezillon@free-electrons.com>
8  *
9  * This program is free software; you can redistribute it and/or modify it
10  * under the terms of the GNU General Public License version 2 as published by
11  * the Free Software Foundation.
12  *
13  * This program is distributed in the hope that it will be useful, but WITHOUT
14  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
15  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
16  * more details.
17  *
18  * You should have received a copy of the GNU General Public License along with
19  * this program.  If not, see <http://www.gnu.org/licenses/>.
20  */
21 
22 #include <linux/of_graph.h>
23 
24 #include <drm/drmP.h>
25 #include <drm/drm_of.h>
26 #include <drm/drm_bridge.h>
27 
28 #include "atmel_hlcdc_dc.h"
29 
30 struct atmel_hlcdc_rgb_output {
31 	struct drm_encoder encoder;
32 	int bus_fmt;
33 };
34 
35 static const struct drm_encoder_funcs atmel_hlcdc_panel_encoder_funcs = {
36 	.destroy = drm_encoder_cleanup,
37 };
38 
39 static struct atmel_hlcdc_rgb_output *
40 atmel_hlcdc_encoder_to_rgb_output(struct drm_encoder *encoder)
41 {
42 	return container_of(encoder, struct atmel_hlcdc_rgb_output, encoder);
43 }
44 
45 int atmel_hlcdc_encoder_get_bus_fmt(struct drm_encoder *encoder)
46 {
47 	struct atmel_hlcdc_rgb_output *output;
48 
49 	output = atmel_hlcdc_encoder_to_rgb_output(encoder);
50 
51 	return output->bus_fmt;
52 }
53 
54 static int atmel_hlcdc_of_bus_fmt(const struct device_node *ep)
55 {
56 	u32 bus_width;
57 	int ret;
58 
59 	ret = of_property_read_u32(ep, "bus-width", &bus_width);
60 	if (ret == -EINVAL)
61 		return 0;
62 	if (ret)
63 		return ret;
64 
65 	switch (bus_width) {
66 	case 12:
67 		return MEDIA_BUS_FMT_RGB444_1X12;
68 	case 16:
69 		return MEDIA_BUS_FMT_RGB565_1X16;
70 	case 18:
71 		return MEDIA_BUS_FMT_RGB666_1X18;
72 	case 24:
73 		return MEDIA_BUS_FMT_RGB888_1X24;
74 	default:
75 		return -EINVAL;
76 	}
77 }
78 
79 static int atmel_hlcdc_attach_endpoint(struct drm_device *dev, int endpoint)
80 {
81 	struct atmel_hlcdc_rgb_output *output;
82 	struct device_node *ep;
83 	struct drm_panel *panel;
84 	struct drm_bridge *bridge;
85 	int ret;
86 
87 	ep = of_graph_get_endpoint_by_regs(dev->dev->of_node, 0, endpoint);
88 	if (!ep)
89 		return -ENODEV;
90 
91 	ret = drm_of_find_panel_or_bridge(dev->dev->of_node, 0, endpoint,
92 					  &panel, &bridge);
93 	if (ret) {
94 		of_node_put(ep);
95 		return ret;
96 	}
97 
98 	output = devm_kzalloc(dev->dev, sizeof(*output), GFP_KERNEL);
99 	if (!output) {
100 		of_node_put(ep);
101 		return -ENOMEM;
102 	}
103 
104 	output->bus_fmt = atmel_hlcdc_of_bus_fmt(ep);
105 	of_node_put(ep);
106 	if (output->bus_fmt < 0) {
107 		dev_err(dev->dev, "endpoint %d: invalid bus width\n", endpoint);
108 		return -EINVAL;
109 	}
110 
111 	ret = drm_encoder_init(dev, &output->encoder,
112 			       &atmel_hlcdc_panel_encoder_funcs,
113 			       DRM_MODE_ENCODER_NONE, NULL);
114 	if (ret)
115 		return ret;
116 
117 	output->encoder.possible_crtcs = 0x1;
118 
119 	if (panel) {
120 		bridge = drm_panel_bridge_add(panel, DRM_MODE_CONNECTOR_Unknown);
121 		if (IS_ERR(bridge))
122 			return PTR_ERR(bridge);
123 	}
124 
125 	if (bridge) {
126 		ret = drm_bridge_attach(&output->encoder, bridge, NULL);
127 		if (!ret)
128 			return 0;
129 
130 		if (panel)
131 			drm_panel_bridge_remove(bridge);
132 	}
133 
134 	drm_encoder_cleanup(&output->encoder);
135 
136 	return ret;
137 }
138 
139 int atmel_hlcdc_create_outputs(struct drm_device *dev)
140 {
141 	int endpoint, ret = 0;
142 	int attached = 0;
143 
144 	/*
145 	 * Always scan the first few endpoints even if we get -ENODEV,
146 	 * but keep going after that as long as we keep getting hits.
147 	 */
148 	for (endpoint = 0; !ret || endpoint < 4; endpoint++) {
149 		ret = atmel_hlcdc_attach_endpoint(dev, endpoint);
150 		if (ret == -ENODEV)
151 			continue;
152 		if (ret)
153 			break;
154 		attached++;
155 	}
156 
157 	/* At least one device was successfully attached.*/
158 	if (ret == -ENODEV && attached)
159 		return 0;
160 
161 	return ret;
162 }
163