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_encoder.h>
 15#include <drm/drm_of.h>
 16#include <drm/drm_bridge.h>
 17
 18#include "atmel_hlcdc_dc.h"
 19
 20struct atmel_hlcdc_rgb_output {
 21	struct drm_encoder encoder;
 22	int bus_fmt;
 23};
 24
 25static const struct drm_encoder_funcs atmel_hlcdc_panel_encoder_funcs = {
 26	.destroy = drm_encoder_cleanup,
 27};
 28
 29static struct atmel_hlcdc_rgb_output *
 30atmel_hlcdc_encoder_to_rgb_output(struct drm_encoder *encoder)
 31{
 32	return container_of(encoder, struct atmel_hlcdc_rgb_output, encoder);
 33}
 34
 35int atmel_hlcdc_encoder_get_bus_fmt(struct drm_encoder *encoder)
 36{
 37	struct atmel_hlcdc_rgb_output *output;
 38
 39	output = atmel_hlcdc_encoder_to_rgb_output(encoder);
 40
 41	return output->bus_fmt;
 42}
 43
 44static int atmel_hlcdc_of_bus_fmt(const struct device_node *ep)
 45{
 46	u32 bus_width;
 47	int ret;
 48
 49	ret = of_property_read_u32(ep, "bus-width", &bus_width);
 50	if (ret == -EINVAL)
 51		return 0;
 52	if (ret)
 53		return ret;
 54
 55	switch (bus_width) {
 56	case 12:
 57		return MEDIA_BUS_FMT_RGB444_1X12;
 58	case 16:
 59		return MEDIA_BUS_FMT_RGB565_1X16;
 60	case 18:
 61		return MEDIA_BUS_FMT_RGB666_1X18;
 62	case 24:
 63		return MEDIA_BUS_FMT_RGB888_1X24;
 64	default:
 65		return -EINVAL;
 66	}
 67}
 68
 69static int atmel_hlcdc_attach_endpoint(struct drm_device *dev, int endpoint)
 70{
 71	struct atmel_hlcdc_rgb_output *output;
 72	struct device_node *ep;
 73	struct drm_panel *panel;
 74	struct drm_bridge *bridge;
 75	int ret;
 76
 77	ep = of_graph_get_endpoint_by_regs(dev->dev->of_node, 0, endpoint);
 78	if (!ep)
 79		return -ENODEV;
 80
 81	ret = drm_of_find_panel_or_bridge(dev->dev->of_node, 0, endpoint,
 82					  &panel, &bridge);
 83	if (ret) {
 84		of_node_put(ep);
 85		return ret;
 86	}
 87
 88	output = devm_kzalloc(dev->dev, sizeof(*output), GFP_KERNEL);
 89	if (!output) {
 90		of_node_put(ep);
 91		return -ENOMEM;
 92	}
 93
 94	output->bus_fmt = atmel_hlcdc_of_bus_fmt(ep);
 95	of_node_put(ep);
 96	if (output->bus_fmt < 0) {
 97		dev_err(dev->dev, "endpoint %d: invalid bus width\n", endpoint);
 98		return -EINVAL;
 99	}
100
101	ret = drm_encoder_init(dev, &output->encoder,
102			       &atmel_hlcdc_panel_encoder_funcs,
103			       DRM_MODE_ENCODER_NONE, NULL);
104	if (ret)
105		return ret;
106
107	output->encoder.possible_crtcs = 0x1;
108
109	if (panel) {
110		bridge = drm_panel_bridge_add(panel, DRM_MODE_CONNECTOR_Unknown);
111		if (IS_ERR(bridge))
112			return PTR_ERR(bridge);
113	}
114
115	if (bridge) {
116		ret = drm_bridge_attach(&output->encoder, bridge, NULL);
117		if (!ret)
118			return 0;
119
120		if (panel)
121			drm_panel_bridge_remove(bridge);
122	}
123
124	drm_encoder_cleanup(&output->encoder);
125
126	return ret;
127}
128
129int atmel_hlcdc_create_outputs(struct drm_device *dev)
130{
131	int endpoint, ret = 0;
132	int attached = 0;
133
134	/*
135	 * Always scan the first few endpoints even if we get -ENODEV,
136	 * but keep going after that as long as we keep getting hits.
137	 */
138	for (endpoint = 0; !ret || endpoint < 4; endpoint++) {
139		ret = atmel_hlcdc_attach_endpoint(dev, endpoint);
140		if (ret == -ENODEV)
141			continue;
142		if (ret)
143			break;
144		attached++;
145	}
146
147	/* At least one device was successfully attached.*/
148	if (ret == -ENODEV && attached)
149		return 0;
150
151	return ret;
152}