xref: /openbmc/linux/drivers/gpu/drm/sun4i/sun4i_rgb.c (revision 7f6964c5)
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/drmP.h>
12 #include <drm/drm_atomic_helper.h>
13 #include <drm/drm_of.h>
14 #include <drm/drm_panel.h>
15 #include <drm/drm_probe_helper.h>
16 
17 #include "sun4i_crtc.h"
18 #include "sun4i_tcon.h"
19 #include "sun4i_rgb.h"
20 
21 struct sun4i_rgb {
22 	struct drm_connector	connector;
23 	struct drm_encoder	encoder;
24 
25 	struct sun4i_tcon	*tcon;
26 	struct drm_panel	*panel;
27 	struct drm_bridge	*bridge;
28 };
29 
30 static inline struct sun4i_rgb *
31 drm_connector_to_sun4i_rgb(struct drm_connector *connector)
32 {
33 	return container_of(connector, struct sun4i_rgb,
34 			    connector);
35 }
36 
37 static inline struct sun4i_rgb *
38 drm_encoder_to_sun4i_rgb(struct drm_encoder *encoder)
39 {
40 	return container_of(encoder, struct sun4i_rgb,
41 			    encoder);
42 }
43 
44 static int sun4i_rgb_get_modes(struct drm_connector *connector)
45 {
46 	struct sun4i_rgb *rgb =
47 		drm_connector_to_sun4i_rgb(connector);
48 
49 	return drm_panel_get_modes(rgb->panel);
50 }
51 
52 /*
53  * VESA DMT defines a tolerance of 0.5% on the pixel clock, while the
54  * CVT spec reuses that tolerance in its examples, so it looks to be a
55  * good default tolerance for the EDID-based modes. Define it to 5 per
56  * mille to avoid floating point operations.
57  */
58 #define SUN4I_RGB_DOTCLOCK_TOLERANCE_PER_MILLE	5
59 
60 static enum drm_mode_status sun4i_rgb_mode_valid(struct drm_encoder *crtc,
61 						 const struct drm_display_mode *mode)
62 {
63 	struct sun4i_rgb *rgb = drm_encoder_to_sun4i_rgb(crtc);
64 	struct sun4i_tcon *tcon = rgb->tcon;
65 	u32 hsync = mode->hsync_end - mode->hsync_start;
66 	u32 vsync = mode->vsync_end - mode->vsync_start;
67 	unsigned long long rate = mode->clock * 1000;
68 	unsigned long long lowest, highest;
69 	unsigned long long rounded_rate;
70 
71 	DRM_DEBUG_DRIVER("Validating modes...\n");
72 
73 	if (hsync < 1)
74 		return MODE_HSYNC_NARROW;
75 
76 	if (hsync > 0x3ff)
77 		return MODE_HSYNC_WIDE;
78 
79 	if ((mode->hdisplay < 1) || (mode->htotal < 1))
80 		return MODE_H_ILLEGAL;
81 
82 	if ((mode->hdisplay > 0x7ff) || (mode->htotal > 0xfff))
83 		return MODE_BAD_HVALUE;
84 
85 	DRM_DEBUG_DRIVER("Horizontal parameters OK\n");
86 
87 	if (vsync < 1)
88 		return MODE_VSYNC_NARROW;
89 
90 	if (vsync > 0x3ff)
91 		return MODE_VSYNC_WIDE;
92 
93 	if ((mode->vdisplay < 1) || (mode->vtotal < 1))
94 		return MODE_V_ILLEGAL;
95 
96 	if ((mode->vdisplay > 0x7ff) || (mode->vtotal > 0xfff))
97 		return MODE_BAD_VVALUE;
98 
99 	DRM_DEBUG_DRIVER("Vertical parameters OK\n");
100 
101 	/*
102 	 * TODO: We should use the struct display_timing if available
103 	 * and / or trying to stretch the timings within that
104 	 * tolerancy to take care of panels that we wouldn't be able
105 	 * to have a exact match for.
106 	 */
107 	if (rgb->panel) {
108 		DRM_DEBUG_DRIVER("RGB panel used, skipping clock rate checks");
109 		goto out;
110 	}
111 
112 	/*
113 	 * That shouldn't ever happen unless something is really wrong, but it
114 	 * doesn't harm to check.
115 	 */
116 	if (!rgb->bridge)
117 		goto out;
118 
119 	tcon->dclk_min_div = 6;
120 	tcon->dclk_max_div = 127;
121 	rounded_rate = clk_round_rate(tcon->dclk, rate);
122 
123 	lowest = rate * (1000 - SUN4I_RGB_DOTCLOCK_TOLERANCE_PER_MILLE);
124 	do_div(lowest, 1000);
125 	if (rounded_rate < lowest)
126 		return MODE_CLOCK_LOW;
127 
128 	highest = rate * (1000 + SUN4I_RGB_DOTCLOCK_TOLERANCE_PER_MILLE);
129 	do_div(highest, 1000);
130 	if (rounded_rate > highest)
131 		return MODE_CLOCK_HIGH;
132 
133 out:
134 	DRM_DEBUG_DRIVER("Clock rate OK\n");
135 
136 	return MODE_OK;
137 }
138 
139 static struct drm_connector_helper_funcs sun4i_rgb_con_helper_funcs = {
140 	.get_modes	= sun4i_rgb_get_modes,
141 };
142 
143 static void
144 sun4i_rgb_connector_destroy(struct drm_connector *connector)
145 {
146 	struct sun4i_rgb *rgb = drm_connector_to_sun4i_rgb(connector);
147 
148 	drm_panel_detach(rgb->panel);
149 	drm_connector_cleanup(connector);
150 }
151 
152 static const struct drm_connector_funcs sun4i_rgb_con_funcs = {
153 	.fill_modes		= drm_helper_probe_single_connector_modes,
154 	.destroy		= sun4i_rgb_connector_destroy,
155 	.reset			= drm_atomic_helper_connector_reset,
156 	.atomic_duplicate_state	= drm_atomic_helper_connector_duplicate_state,
157 	.atomic_destroy_state	= drm_atomic_helper_connector_destroy_state,
158 };
159 
160 static void sun4i_rgb_encoder_enable(struct drm_encoder *encoder)
161 {
162 	struct sun4i_rgb *rgb = drm_encoder_to_sun4i_rgb(encoder);
163 
164 	DRM_DEBUG_DRIVER("Enabling RGB output\n");
165 
166 	if (rgb->panel) {
167 		drm_panel_prepare(rgb->panel);
168 		drm_panel_enable(rgb->panel);
169 	}
170 }
171 
172 static void sun4i_rgb_encoder_disable(struct drm_encoder *encoder)
173 {
174 	struct sun4i_rgb *rgb = drm_encoder_to_sun4i_rgb(encoder);
175 
176 	DRM_DEBUG_DRIVER("Disabling RGB output\n");
177 
178 	if (rgb->panel) {
179 		drm_panel_disable(rgb->panel);
180 		drm_panel_unprepare(rgb->panel);
181 	}
182 }
183 
184 static struct drm_encoder_helper_funcs sun4i_rgb_enc_helper_funcs = {
185 	.disable	= sun4i_rgb_encoder_disable,
186 	.enable		= sun4i_rgb_encoder_enable,
187 	.mode_valid	= sun4i_rgb_mode_valid,
188 };
189 
190 static void sun4i_rgb_enc_destroy(struct drm_encoder *encoder)
191 {
192 	drm_encoder_cleanup(encoder);
193 }
194 
195 static struct drm_encoder_funcs sun4i_rgb_enc_funcs = {
196 	.destroy	= sun4i_rgb_enc_destroy,
197 };
198 
199 int sun4i_rgb_init(struct drm_device *drm, struct sun4i_tcon *tcon)
200 {
201 	struct drm_encoder *encoder;
202 	struct sun4i_rgb *rgb;
203 	int ret;
204 
205 	rgb = devm_kzalloc(drm->dev, sizeof(*rgb), GFP_KERNEL);
206 	if (!rgb)
207 		return -ENOMEM;
208 	rgb->tcon = tcon;
209 	encoder = &rgb->encoder;
210 
211 	ret = drm_of_find_panel_or_bridge(tcon->dev->of_node, 1, 0,
212 					  &rgb->panel, &rgb->bridge);
213 	if (ret) {
214 		dev_info(drm->dev, "No panel or bridge found... RGB output disabled\n");
215 		return 0;
216 	}
217 
218 	drm_encoder_helper_add(&rgb->encoder,
219 			       &sun4i_rgb_enc_helper_funcs);
220 	ret = drm_encoder_init(drm,
221 			       &rgb->encoder,
222 			       &sun4i_rgb_enc_funcs,
223 			       DRM_MODE_ENCODER_NONE,
224 			       NULL);
225 	if (ret) {
226 		dev_err(drm->dev, "Couldn't initialise the rgb encoder\n");
227 		goto err_out;
228 	}
229 
230 	/* The RGB encoder can only work with the TCON channel 0 */
231 	rgb->encoder.possible_crtcs = drm_crtc_mask(&tcon->crtc->crtc);
232 
233 	if (rgb->panel) {
234 		drm_connector_helper_add(&rgb->connector,
235 					 &sun4i_rgb_con_helper_funcs);
236 		ret = drm_connector_init(drm, &rgb->connector,
237 					 &sun4i_rgb_con_funcs,
238 					 DRM_MODE_CONNECTOR_Unknown);
239 		if (ret) {
240 			dev_err(drm->dev, "Couldn't initialise the rgb connector\n");
241 			goto err_cleanup_connector;
242 		}
243 
244 		drm_connector_attach_encoder(&rgb->connector,
245 						  &rgb->encoder);
246 
247 		ret = drm_panel_attach(rgb->panel, &rgb->connector);
248 		if (ret) {
249 			dev_err(drm->dev, "Couldn't attach our panel\n");
250 			goto err_cleanup_connector;
251 		}
252 	}
253 
254 	if (rgb->bridge) {
255 		ret = drm_bridge_attach(encoder, rgb->bridge, NULL);
256 		if (ret) {
257 			dev_err(drm->dev, "Couldn't attach our bridge\n");
258 			goto err_cleanup_connector;
259 		}
260 	}
261 
262 	return 0;
263 
264 err_cleanup_connector:
265 	drm_encoder_cleanup(&rgb->encoder);
266 err_out:
267 	return ret;
268 }
269 EXPORT_SYMBOL(sun4i_rgb_init);
270