1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2023 Loongson Technology Corporation Limited
4  */
5 
6 #include <drm/drm_atomic_helper.h>
7 #include <drm/drm_edid.h>
8 #include <drm/drm_probe_helper.h>
9 
10 #include "lsdc_drv.h"
11 #include "lsdc_output.h"
12 
13 /*
14  * The display controller in the LS7A1000 exports two DVO interfaces, thus
15  * external encoder is required, except connected to the DPI panel directly.
16  *
17  *       ___________________                                     _________
18  *      |            -------|                                   |         |
19  *      |  CRTC0 --> | DVO0 ----> Encoder0 ---> Connector0 ---> | Display |
20  *      |  _   _     -------|        ^             ^            |_________|
21  *      | | | | |  +------+ |        |             |
22  *      | |_| |_|  | i2c6 | <--------+-------------+
23  *      |          +------+ |
24  *      |                   |
25  *      |  DC in LS7A1000   |
26  *      |                   |
27  *      |  _   _   +------+ |
28  *      | | | | |  | i2c7 | <--------+-------------+
29  *      | |_| |_|  +------+ |        |             |             _________
30  *      |            -------|        |             |            |         |
31  *      |  CRTC1 --> | DVO1 ----> Encoder1 ---> Connector1 ---> |  Panel  |
32  *      |            -------|                                   |_________|
33  *      |___________________|
34  *
35  * Currently, we assume the external encoders connected to the DVO are
36  * transparent. Loongson's DVO interface can directly drive RGB888 panels.
37  *
38  *  TODO: Add support for non-transparent encoders
39  */
40 
41 static int ls7a1000_dpi_connector_get_modes(struct drm_connector *conn)
42 {
43 	unsigned int num = 0;
44 	struct edid *edid;
45 
46 	if (conn->ddc) {
47 		edid = drm_get_edid(conn, conn->ddc);
48 		if (edid) {
49 			drm_connector_update_edid_property(conn, edid);
50 			num = drm_add_edid_modes(conn, edid);
51 			kfree(edid);
52 		}
53 
54 		return num;
55 	}
56 
57 	num = drm_add_modes_noedid(conn, 1920, 1200);
58 
59 	drm_set_preferred_mode(conn, 1024, 768);
60 
61 	return num;
62 }
63 
64 static struct drm_encoder *
65 ls7a1000_dpi_connector_get_best_encoder(struct drm_connector *connector,
66 					struct drm_atomic_state *state)
67 {
68 	struct lsdc_output *output = connector_to_lsdc_output(connector);
69 
70 	return &output->encoder;
71 }
72 
73 static const struct drm_connector_helper_funcs
74 ls7a1000_dpi_connector_helpers = {
75 	.atomic_best_encoder = ls7a1000_dpi_connector_get_best_encoder,
76 	.get_modes = ls7a1000_dpi_connector_get_modes,
77 };
78 
79 static enum drm_connector_status
80 ls7a1000_dpi_connector_detect(struct drm_connector *connector, bool force)
81 {
82 	struct i2c_adapter *ddc = connector->ddc;
83 
84 	if (ddc) {
85 		if (drm_probe_ddc(ddc))
86 			return connector_status_connected;
87 
88 		return connector_status_disconnected;
89 	}
90 
91 	return connector_status_unknown;
92 }
93 
94 static const struct drm_connector_funcs ls7a1000_dpi_connector_funcs = {
95 	.detect = ls7a1000_dpi_connector_detect,
96 	.fill_modes = drm_helper_probe_single_connector_modes,
97 	.destroy = drm_connector_cleanup,
98 	.reset = drm_atomic_helper_connector_reset,
99 	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
100 	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state
101 };
102 
103 static void ls7a1000_pipe0_encoder_reset(struct drm_encoder *encoder)
104 {
105 	struct drm_device *ddev = encoder->dev;
106 	struct lsdc_device *ldev = to_lsdc(ddev);
107 
108 	/*
109 	 * We need this for S3 support, screen will not lightup if don't set
110 	 * this register correctly.
111 	 */
112 	lsdc_wreg32(ldev, LSDC_CRTC0_DVO_CONF_REG,
113 		    PHY_CLOCK_POL | PHY_CLOCK_EN | PHY_DATA_EN);
114 }
115 
116 static void ls7a1000_pipe1_encoder_reset(struct drm_encoder *encoder)
117 {
118 	struct drm_device *ddev = encoder->dev;
119 	struct lsdc_device *ldev = to_lsdc(ddev);
120 
121 	/*
122 	 * We need this for S3 support, screen will not lightup if don't set
123 	 * this register correctly.
124 	 */
125 
126 	/* DVO */
127 	lsdc_wreg32(ldev, LSDC_CRTC1_DVO_CONF_REG,
128 		    BIT(31) | PHY_CLOCK_POL | PHY_CLOCK_EN | PHY_DATA_EN);
129 }
130 
131 static const struct drm_encoder_funcs ls7a1000_encoder_funcs[2] = {
132 	{
133 		.reset = ls7a1000_pipe0_encoder_reset,
134 		.destroy = drm_encoder_cleanup,
135 	},
136 	{
137 		.reset = ls7a1000_pipe1_encoder_reset,
138 		.destroy = drm_encoder_cleanup,
139 	},
140 };
141 
142 int ls7a1000_output_init(struct drm_device *ddev,
143 			 struct lsdc_display_pipe *dispipe,
144 			 struct i2c_adapter *ddc,
145 			 unsigned int index)
146 {
147 	struct lsdc_output *output = &dispipe->output;
148 	struct drm_encoder *encoder = &output->encoder;
149 	struct drm_connector *connector = &output->connector;
150 	int ret;
151 
152 	ret = drm_encoder_init(ddev, encoder, &ls7a1000_encoder_funcs[index],
153 			       DRM_MODE_ENCODER_TMDS, "encoder-%u", index);
154 	if (ret)
155 		return ret;
156 
157 	encoder->possible_crtcs = BIT(index);
158 
159 	ret = drm_connector_init_with_ddc(ddev, connector,
160 					  &ls7a1000_dpi_connector_funcs,
161 					  DRM_MODE_CONNECTOR_DPI, ddc);
162 	if (ret)
163 		return ret;
164 
165 	drm_info(ddev, "display pipe-%u has a DVO\n", index);
166 
167 	drm_connector_helper_add(connector, &ls7a1000_dpi_connector_helpers);
168 
169 	drm_connector_attach_encoder(connector, encoder);
170 
171 	connector->polled = DRM_CONNECTOR_POLL_CONNECT |
172 			    DRM_CONNECTOR_POLL_DISCONNECT;
173 
174 	connector->interlace_allowed = 0;
175 	connector->doublescan_allowed = 0;
176 
177 	return 0;
178 }
179