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