1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2014 Traphandler
4  * Copyright (C) 2014 Free Electrons
5  * Copyright (C) 2014 Atmel
6  *
7  * Author: Jean-Jacques Hiblot <jjhiblot@traphandler.com>
8  * Author: Boris BREZILLON <boris.brezillon@free-electrons.com>
9  */
10 
11 #include <linux/media-bus-format.h>
12 #include <linux/of_graph.h>
13 
14 #include <drm/drm_encoder.h>
15 #include <drm/drm_of.h>
16 #include <drm/drm_bridge.h>
17 
18 #include "atmel_hlcdc_dc.h"
19 
20 struct atmel_hlcdc_rgb_output {
21 	struct drm_encoder encoder;
22 	int bus_fmt;
23 };
24 
25 static const struct drm_encoder_funcs atmel_hlcdc_panel_encoder_funcs = {
26 	.destroy = drm_encoder_cleanup,
27 };
28 
29 static struct atmel_hlcdc_rgb_output *
30 atmel_hlcdc_encoder_to_rgb_output(struct drm_encoder *encoder)
31 {
32 	return container_of(encoder, struct atmel_hlcdc_rgb_output, encoder);
33 }
34 
35 int atmel_hlcdc_encoder_get_bus_fmt(struct drm_encoder *encoder)
36 {
37 	struct atmel_hlcdc_rgb_output *output;
38 
39 	output = atmel_hlcdc_encoder_to_rgb_output(encoder);
40 
41 	return output->bus_fmt;
42 }
43 
44 static int atmel_hlcdc_of_bus_fmt(const struct device_node *ep)
45 {
46 	u32 bus_width;
47 	int ret;
48 
49 	ret = of_property_read_u32(ep, "bus-width", &bus_width);
50 	if (ret == -EINVAL)
51 		return 0;
52 	if (ret)
53 		return ret;
54 
55 	switch (bus_width) {
56 	case 12:
57 		return MEDIA_BUS_FMT_RGB444_1X12;
58 	case 16:
59 		return MEDIA_BUS_FMT_RGB565_1X16;
60 	case 18:
61 		return MEDIA_BUS_FMT_RGB666_1X18;
62 	case 24:
63 		return MEDIA_BUS_FMT_RGB888_1X24;
64 	default:
65 		return -EINVAL;
66 	}
67 }
68 
69 static int atmel_hlcdc_attach_endpoint(struct drm_device *dev, int endpoint)
70 {
71 	struct atmel_hlcdc_rgb_output *output;
72 	struct device_node *ep;
73 	struct drm_panel *panel;
74 	struct drm_bridge *bridge;
75 	int ret;
76 
77 	ep = of_graph_get_endpoint_by_regs(dev->dev->of_node, 0, endpoint);
78 	if (!ep)
79 		return -ENODEV;
80 
81 	ret = drm_of_find_panel_or_bridge(dev->dev->of_node, 0, endpoint,
82 					  &panel, &bridge);
83 	if (ret) {
84 		of_node_put(ep);
85 		return ret;
86 	}
87 
88 	output = devm_kzalloc(dev->dev, sizeof(*output), GFP_KERNEL);
89 	if (!output) {
90 		of_node_put(ep);
91 		return -ENOMEM;
92 	}
93 
94 	output->bus_fmt = atmel_hlcdc_of_bus_fmt(ep);
95 	of_node_put(ep);
96 	if (output->bus_fmt < 0) {
97 		dev_err(dev->dev, "endpoint %d: invalid bus width\n", endpoint);
98 		return -EINVAL;
99 	}
100 
101 	ret = drm_encoder_init(dev, &output->encoder,
102 			       &atmel_hlcdc_panel_encoder_funcs,
103 			       DRM_MODE_ENCODER_NONE, NULL);
104 	if (ret)
105 		return ret;
106 
107 	output->encoder.possible_crtcs = 0x1;
108 
109 	if (panel) {
110 		bridge = drm_panel_bridge_add_typed(panel,
111 						    DRM_MODE_CONNECTOR_Unknown);
112 		if (IS_ERR(bridge))
113 			return PTR_ERR(bridge);
114 	}
115 
116 	if (bridge) {
117 		ret = drm_bridge_attach(&output->encoder, bridge, NULL, 0);
118 		if (!ret)
119 			return 0;
120 
121 		if (panel)
122 			drm_panel_bridge_remove(bridge);
123 	}
124 
125 	drm_encoder_cleanup(&output->encoder);
126 
127 	return ret;
128 }
129 
130 int atmel_hlcdc_create_outputs(struct drm_device *dev)
131 {
132 	int endpoint, ret = 0;
133 	int attached = 0;
134 
135 	/*
136 	 * Always scan the first few endpoints even if we get -ENODEV,
137 	 * but keep going after that as long as we keep getting hits.
138 	 */
139 	for (endpoint = 0; !ret || endpoint < 4; endpoint++) {
140 		ret = atmel_hlcdc_attach_endpoint(dev, endpoint);
141 		if (ret == -ENODEV)
142 			continue;
143 		if (ret)
144 			break;
145 		attached++;
146 	}
147 
148 	/* At least one device was successfully attached.*/
149 	if (ret == -ENODEV && attached)
150 		return 0;
151 
152 	return ret;
153 }
154