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 *
atmel_hlcdc_encoder_to_rgb_output(struct drm_encoder * encoder)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
atmel_hlcdc_encoder_get_bus_fmt(struct drm_encoder * encoder)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
atmel_hlcdc_of_bus_fmt(const struct device_node * ep)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
atmel_hlcdc_attach_endpoint(struct drm_device * dev,int endpoint)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
atmel_hlcdc_create_outputs(struct drm_device * dev)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