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