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
22struct atmel_hlcdc_rgb_output {
23	struct drm_encoder encoder;
24	int bus_fmt;
25};
26
27static struct atmel_hlcdc_rgb_output *
28atmel_hlcdc_encoder_to_rgb_output(struct drm_encoder *encoder)
29{
30	return container_of(encoder, struct atmel_hlcdc_rgb_output, encoder);
31}
32
33int 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
42static 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
67static 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
127int 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