xref: /openbmc/linux/drivers/gpu/drm/sun4i/sun4i_rgb.c (revision 15e3ae36)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (C) 2015 Free Electrons
4  * Copyright (C) 2015 NextThing Co
5  *
6  * Maxime Ripard <maxime.ripard@free-electrons.com>
7  */
8 
9 #include <linux/clk.h>
10 
11 #include <drm/drm_atomic_helper.h>
12 #include <drm/drm_bridge.h>
13 #include <drm/drm_of.h>
14 #include <drm/drm_panel.h>
15 #include <drm/drm_print.h>
16 #include <drm/drm_probe_helper.h>
17 
18 #include "sun4i_crtc.h"
19 #include "sun4i_tcon.h"
20 #include "sun4i_rgb.h"
21 
22 struct sun4i_rgb {
23 	struct drm_connector	connector;
24 	struct drm_encoder	encoder;
25 
26 	struct sun4i_tcon	*tcon;
27 	struct drm_panel	*panel;
28 	struct drm_bridge	*bridge;
29 };
30 
31 static inline struct sun4i_rgb *
32 drm_connector_to_sun4i_rgb(struct drm_connector *connector)
33 {
34 	return container_of(connector, struct sun4i_rgb,
35 			    connector);
36 }
37 
38 static inline struct sun4i_rgb *
39 drm_encoder_to_sun4i_rgb(struct drm_encoder *encoder)
40 {
41 	return container_of(encoder, struct sun4i_rgb,
42 			    encoder);
43 }
44 
45 static int sun4i_rgb_get_modes(struct drm_connector *connector)
46 {
47 	struct sun4i_rgb *rgb =
48 		drm_connector_to_sun4i_rgb(connector);
49 
50 	return drm_panel_get_modes(rgb->panel, connector);
51 }
52 
53 /*
54  * VESA DMT defines a tolerance of 0.5% on the pixel clock, while the
55  * CVT spec reuses that tolerance in its examples, so it looks to be a
56  * good default tolerance for the EDID-based modes. Define it to 5 per
57  * mille to avoid floating point operations.
58  */
59 #define SUN4I_RGB_DOTCLOCK_TOLERANCE_PER_MILLE	5
60 
61 static enum drm_mode_status sun4i_rgb_mode_valid(struct drm_encoder *crtc,
62 						 const struct drm_display_mode *mode)
63 {
64 	struct sun4i_rgb *rgb = drm_encoder_to_sun4i_rgb(crtc);
65 	struct sun4i_tcon *tcon = rgb->tcon;
66 	u32 hsync = mode->hsync_end - mode->hsync_start;
67 	u32 vsync = mode->vsync_end - mode->vsync_start;
68 	unsigned long long rate = mode->clock * 1000;
69 	unsigned long long lowest, highest;
70 	unsigned long long rounded_rate;
71 
72 	DRM_DEBUG_DRIVER("Validating modes...\n");
73 
74 	if (hsync < 1)
75 		return MODE_HSYNC_NARROW;
76 
77 	if (hsync > 0x3ff)
78 		return MODE_HSYNC_WIDE;
79 
80 	if ((mode->hdisplay < 1) || (mode->htotal < 1))
81 		return MODE_H_ILLEGAL;
82 
83 	if ((mode->hdisplay > 0x7ff) || (mode->htotal > 0xfff))
84 		return MODE_BAD_HVALUE;
85 
86 	DRM_DEBUG_DRIVER("Horizontal parameters OK\n");
87 
88 	if (vsync < 1)
89 		return MODE_VSYNC_NARROW;
90 
91 	if (vsync > 0x3ff)
92 		return MODE_VSYNC_WIDE;
93 
94 	if ((mode->vdisplay < 1) || (mode->vtotal < 1))
95 		return MODE_V_ILLEGAL;
96 
97 	if ((mode->vdisplay > 0x7ff) || (mode->vtotal > 0xfff))
98 		return MODE_BAD_VVALUE;
99 
100 	DRM_DEBUG_DRIVER("Vertical parameters OK\n");
101 
102 	/*
103 	 * TODO: We should use the struct display_timing if available
104 	 * and / or trying to stretch the timings within that
105 	 * tolerancy to take care of panels that we wouldn't be able
106 	 * to have a exact match for.
107 	 */
108 	if (rgb->panel) {
109 		DRM_DEBUG_DRIVER("RGB panel used, skipping clock rate checks");
110 		goto out;
111 	}
112 
113 	/*
114 	 * That shouldn't ever happen unless something is really wrong, but it
115 	 * doesn't harm to check.
116 	 */
117 	if (!rgb->bridge)
118 		goto out;
119 
120 	tcon->dclk_min_div = 6;
121 	tcon->dclk_max_div = 127;
122 	rounded_rate = clk_round_rate(tcon->dclk, rate);
123 
124 	lowest = rate * (1000 - SUN4I_RGB_DOTCLOCK_TOLERANCE_PER_MILLE);
125 	do_div(lowest, 1000);
126 	if (rounded_rate < lowest)
127 		return MODE_CLOCK_LOW;
128 
129 	highest = rate * (1000 + SUN4I_RGB_DOTCLOCK_TOLERANCE_PER_MILLE);
130 	do_div(highest, 1000);
131 	if (rounded_rate > highest)
132 		return MODE_CLOCK_HIGH;
133 
134 out:
135 	DRM_DEBUG_DRIVER("Clock rate OK\n");
136 
137 	return MODE_OK;
138 }
139 
140 static struct drm_connector_helper_funcs sun4i_rgb_con_helper_funcs = {
141 	.get_modes	= sun4i_rgb_get_modes,
142 };
143 
144 static void
145 sun4i_rgb_connector_destroy(struct drm_connector *connector)
146 {
147 	struct sun4i_rgb *rgb = drm_connector_to_sun4i_rgb(connector);
148 
149 	drm_panel_detach(rgb->panel);
150 	drm_connector_cleanup(connector);
151 }
152 
153 static const struct drm_connector_funcs sun4i_rgb_con_funcs = {
154 	.fill_modes		= drm_helper_probe_single_connector_modes,
155 	.destroy		= sun4i_rgb_connector_destroy,
156 	.reset			= drm_atomic_helper_connector_reset,
157 	.atomic_duplicate_state	= drm_atomic_helper_connector_duplicate_state,
158 	.atomic_destroy_state	= drm_atomic_helper_connector_destroy_state,
159 };
160 
161 static void sun4i_rgb_encoder_enable(struct drm_encoder *encoder)
162 {
163 	struct sun4i_rgb *rgb = drm_encoder_to_sun4i_rgb(encoder);
164 
165 	DRM_DEBUG_DRIVER("Enabling RGB output\n");
166 
167 	if (rgb->panel) {
168 		drm_panel_prepare(rgb->panel);
169 		drm_panel_enable(rgb->panel);
170 	}
171 }
172 
173 static void sun4i_rgb_encoder_disable(struct drm_encoder *encoder)
174 {
175 	struct sun4i_rgb *rgb = drm_encoder_to_sun4i_rgb(encoder);
176 
177 	DRM_DEBUG_DRIVER("Disabling RGB output\n");
178 
179 	if (rgb->panel) {
180 		drm_panel_disable(rgb->panel);
181 		drm_panel_unprepare(rgb->panel);
182 	}
183 }
184 
185 static struct drm_encoder_helper_funcs sun4i_rgb_enc_helper_funcs = {
186 	.disable	= sun4i_rgb_encoder_disable,
187 	.enable		= sun4i_rgb_encoder_enable,
188 	.mode_valid	= sun4i_rgb_mode_valid,
189 };
190 
191 static void sun4i_rgb_enc_destroy(struct drm_encoder *encoder)
192 {
193 	drm_encoder_cleanup(encoder);
194 }
195 
196 static struct drm_encoder_funcs sun4i_rgb_enc_funcs = {
197 	.destroy	= sun4i_rgb_enc_destroy,
198 };
199 
200 int sun4i_rgb_init(struct drm_device *drm, struct sun4i_tcon *tcon)
201 {
202 	struct drm_encoder *encoder;
203 	struct sun4i_rgb *rgb;
204 	int ret;
205 
206 	rgb = devm_kzalloc(drm->dev, sizeof(*rgb), GFP_KERNEL);
207 	if (!rgb)
208 		return -ENOMEM;
209 	rgb->tcon = tcon;
210 	encoder = &rgb->encoder;
211 
212 	ret = drm_of_find_panel_or_bridge(tcon->dev->of_node, 1, 0,
213 					  &rgb->panel, &rgb->bridge);
214 	if (ret) {
215 		dev_info(drm->dev, "No panel or bridge found... RGB output disabled\n");
216 		return 0;
217 	}
218 
219 	drm_encoder_helper_add(&rgb->encoder,
220 			       &sun4i_rgb_enc_helper_funcs);
221 	ret = drm_encoder_init(drm,
222 			       &rgb->encoder,
223 			       &sun4i_rgb_enc_funcs,
224 			       DRM_MODE_ENCODER_NONE,
225 			       NULL);
226 	if (ret) {
227 		dev_err(drm->dev, "Couldn't initialise the rgb encoder\n");
228 		goto err_out;
229 	}
230 
231 	/* The RGB encoder can only work with the TCON channel 0 */
232 	rgb->encoder.possible_crtcs = drm_crtc_mask(&tcon->crtc->crtc);
233 
234 	if (rgb->panel) {
235 		drm_connector_helper_add(&rgb->connector,
236 					 &sun4i_rgb_con_helper_funcs);
237 		ret = drm_connector_init(drm, &rgb->connector,
238 					 &sun4i_rgb_con_funcs,
239 					 DRM_MODE_CONNECTOR_Unknown);
240 		if (ret) {
241 			dev_err(drm->dev, "Couldn't initialise the rgb connector\n");
242 			goto err_cleanup_connector;
243 		}
244 
245 		drm_connector_attach_encoder(&rgb->connector,
246 						  &rgb->encoder);
247 
248 		ret = drm_panel_attach(rgb->panel, &rgb->connector);
249 		if (ret) {
250 			dev_err(drm->dev, "Couldn't attach our panel\n");
251 			goto err_cleanup_connector;
252 		}
253 	}
254 
255 	if (rgb->bridge) {
256 		ret = drm_bridge_attach(encoder, rgb->bridge, NULL, 0);
257 		if (ret) {
258 			dev_err(drm->dev, "Couldn't attach our bridge\n");
259 			goto err_cleanup_connector;
260 		}
261 	}
262 
263 	return 0;
264 
265 err_cleanup_connector:
266 	drm_encoder_cleanup(&rgb->encoder);
267 err_out:
268 	return ret;
269 }
270 EXPORT_SYMBOL(sun4i_rgb_init);
271