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}