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