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