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
 21struct atmel_hlcdc_rgb_output {
 22	struct drm_encoder encoder;
 23	int bus_fmt;
 24};
 25
 26static struct atmel_hlcdc_rgb_output *
 27atmel_hlcdc_encoder_to_rgb_output(struct drm_encoder *encoder)
 28{
 29	return container_of(encoder, struct atmel_hlcdc_rgb_output, encoder);
 30}
 31
 32int 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
 41static 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
 66static 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
126int 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}