atmel_hlcdc_output.c

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