xref: /linux/drivers/gpu/drm/sun4i/sun4i_rgb.c (revision 05909cd9a0c8811731b38697af13075e8954314f)
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 #include <drm/drm_simple_kms_helper.h>
18 
19 #include "sun4i_crtc.h"
20 #include "sun4i_tcon.h"
21 #include "sun4i_rgb.h"
22 
23 struct sun4i_rgb {
24 	struct drm_connector	connector;
25 	struct drm_encoder	encoder;
26 
27 	struct sun4i_tcon	*tcon;
28 	struct drm_panel	*panel;
29 	struct drm_bridge	*bridge;
30 };
31 
32 static inline struct sun4i_rgb *
33 drm_connector_to_sun4i_rgb(struct drm_connector *connector)
34 {
35 	return container_of(connector, struct sun4i_rgb,
36 			    connector);
37 }
38 
39 static inline struct sun4i_rgb *
40 drm_encoder_to_sun4i_rgb(struct drm_encoder *encoder)
41 {
42 	return container_of(encoder, struct sun4i_rgb,
43 			    encoder);
44 }
45 
46 static int sun4i_rgb_get_modes(struct drm_connector *connector)
47 {
48 	struct sun4i_rgb *rgb =
49 		drm_connector_to_sun4i_rgb(connector);
50 
51 	return drm_panel_get_modes(rgb->panel, connector);
52 }
53 
54 /*
55  * VESA DMT defines a tolerance of 0.5% on the pixel clock, while the
56  * CVT spec reuses that tolerance in its examples, so it looks to be a
57  * good default tolerance for the EDID-based modes. Define it to 5 per
58  * mille to avoid floating point operations.
59  */
60 #define SUN4I_RGB_DOTCLOCK_TOLERANCE_PER_MILLE	5
61 
62 static enum drm_mode_status sun4i_rgb_mode_valid(struct drm_encoder *crtc,
63 						 const struct drm_display_mode *mode)
64 {
65 	struct sun4i_rgb *rgb = drm_encoder_to_sun4i_rgb(crtc);
66 	struct sun4i_tcon *tcon = rgb->tcon;
67 	u32 hsync = mode->hsync_end - mode->hsync_start;
68 	u32 vsync = mode->vsync_end - mode->vsync_start;
69 	unsigned long long rate = mode->clock * 1000;
70 	unsigned long long lowest, highest;
71 	unsigned long long rounded_rate;
72 
73 	DRM_DEBUG_DRIVER("Validating modes...\n");
74 
75 	if (hsync < 1)
76 		return MODE_HSYNC_NARROW;
77 
78 	if (hsync > 0x3ff)
79 		return MODE_HSYNC_WIDE;
80 
81 	if ((mode->hdisplay < 1) || (mode->htotal < 1))
82 		return MODE_H_ILLEGAL;
83 
84 	if ((mode->hdisplay > 0x7ff) || (mode->htotal > 0xfff))
85 		return MODE_BAD_HVALUE;
86 
87 	DRM_DEBUG_DRIVER("Horizontal parameters OK\n");
88 
89 	if (vsync < 1)
90 		return MODE_VSYNC_NARROW;
91 
92 	if (vsync > 0x3ff)
93 		return MODE_VSYNC_WIDE;
94 
95 	if ((mode->vdisplay < 1) || (mode->vtotal < 1))
96 		return MODE_V_ILLEGAL;
97 
98 	if ((mode->vdisplay > 0x7ff) || (mode->vtotal > 0xfff))
99 		return MODE_BAD_VVALUE;
100 
101 	DRM_DEBUG_DRIVER("Vertical parameters OK\n");
102 
103 	/*
104 	 * TODO: We should use the struct display_timing if available
105 	 * and / or trying to stretch the timings within that
106 	 * tolerancy to take care of panels that we wouldn't be able
107 	 * to have a exact match for.
108 	 */
109 	if (rgb->panel) {
110 		DRM_DEBUG_DRIVER("RGB panel used, skipping clock rate checks");
111 		goto out;
112 	}
113 
114 	/*
115 	 * That shouldn't ever happen unless something is really wrong, but it
116 	 * doesn't harm to check.
117 	 */
118 	if (!rgb->bridge)
119 		goto out;
120 
121 	tcon->dclk_min_div = 6;
122 	tcon->dclk_max_div = 127;
123 	rounded_rate = clk_round_rate(tcon->dclk, rate);
124 
125 	lowest = rate * (1000 - SUN4I_RGB_DOTCLOCK_TOLERANCE_PER_MILLE);
126 	do_div(lowest, 1000);
127 	if (rounded_rate < lowest)
128 		return MODE_CLOCK_LOW;
129 
130 	highest = rate * (1000 + SUN4I_RGB_DOTCLOCK_TOLERANCE_PER_MILLE);
131 	do_div(highest, 1000);
132 	if (rounded_rate > highest)
133 		return MODE_CLOCK_HIGH;
134 
135 out:
136 	DRM_DEBUG_DRIVER("Clock rate OK\n");
137 
138 	return MODE_OK;
139 }
140 
141 static struct drm_connector_helper_funcs sun4i_rgb_con_helper_funcs = {
142 	.get_modes	= sun4i_rgb_get_modes,
143 };
144 
145 static void
146 sun4i_rgb_connector_destroy(struct drm_connector *connector)
147 {
148 	struct sun4i_rgb *rgb = drm_connector_to_sun4i_rgb(connector);
149 
150 	drm_panel_detach(rgb->panel);
151 	drm_connector_cleanup(connector);
152 }
153 
154 static const struct drm_connector_funcs sun4i_rgb_con_funcs = {
155 	.fill_modes		= drm_helper_probe_single_connector_modes,
156 	.destroy		= sun4i_rgb_connector_destroy,
157 	.reset			= drm_atomic_helper_connector_reset,
158 	.atomic_duplicate_state	= drm_atomic_helper_connector_duplicate_state,
159 	.atomic_destroy_state	= drm_atomic_helper_connector_destroy_state,
160 };
161 
162 static void sun4i_rgb_encoder_enable(struct drm_encoder *encoder)
163 {
164 	struct sun4i_rgb *rgb = drm_encoder_to_sun4i_rgb(encoder);
165 
166 	DRM_DEBUG_DRIVER("Enabling RGB output\n");
167 
168 	if (rgb->panel) {
169 		drm_panel_prepare(rgb->panel);
170 		drm_panel_enable(rgb->panel);
171 	}
172 }
173 
174 static void sun4i_rgb_encoder_disable(struct drm_encoder *encoder)
175 {
176 	struct sun4i_rgb *rgb = drm_encoder_to_sun4i_rgb(encoder);
177 
178 	DRM_DEBUG_DRIVER("Disabling RGB output\n");
179 
180 	if (rgb->panel) {
181 		drm_panel_disable(rgb->panel);
182 		drm_panel_unprepare(rgb->panel);
183 	}
184 }
185 
186 static struct drm_encoder_helper_funcs sun4i_rgb_enc_helper_funcs = {
187 	.disable	= sun4i_rgb_encoder_disable,
188 	.enable		= sun4i_rgb_encoder_enable,
189 	.mode_valid	= sun4i_rgb_mode_valid,
190 };
191 
192 int sun4i_rgb_init(struct drm_device *drm, struct sun4i_tcon *tcon)
193 {
194 	struct drm_encoder *encoder;
195 	struct sun4i_rgb *rgb;
196 	int ret;
197 
198 	rgb = devm_kzalloc(drm->dev, sizeof(*rgb), GFP_KERNEL);
199 	if (!rgb)
200 		return -ENOMEM;
201 	rgb->tcon = tcon;
202 	encoder = &rgb->encoder;
203 
204 	ret = drm_of_find_panel_or_bridge(tcon->dev->of_node, 1, 0,
205 					  &rgb->panel, &rgb->bridge);
206 	if (ret) {
207 		dev_info(drm->dev, "No panel or bridge found... RGB output disabled\n");
208 		return 0;
209 	}
210 
211 	drm_encoder_helper_add(&rgb->encoder,
212 			       &sun4i_rgb_enc_helper_funcs);
213 	ret = drm_simple_encoder_init(drm, &rgb->encoder,
214 				      DRM_MODE_ENCODER_NONE);
215 	if (ret) {
216 		dev_err(drm->dev, "Couldn't initialise the rgb encoder\n");
217 		goto err_out;
218 	}
219 
220 	/* The RGB encoder can only work with the TCON channel 0 */
221 	rgb->encoder.possible_crtcs = drm_crtc_mask(&tcon->crtc->crtc);
222 
223 	if (rgb->panel) {
224 		drm_connector_helper_add(&rgb->connector,
225 					 &sun4i_rgb_con_helper_funcs);
226 		ret = drm_connector_init(drm, &rgb->connector,
227 					 &sun4i_rgb_con_funcs,
228 					 DRM_MODE_CONNECTOR_Unknown);
229 		if (ret) {
230 			dev_err(drm->dev, "Couldn't initialise the rgb connector\n");
231 			goto err_cleanup_connector;
232 		}
233 
234 		drm_connector_attach_encoder(&rgb->connector,
235 						  &rgb->encoder);
236 
237 		ret = drm_panel_attach(rgb->panel, &rgb->connector);
238 		if (ret) {
239 			dev_err(drm->dev, "Couldn't attach our panel\n");
240 			goto err_cleanup_connector;
241 		}
242 	}
243 
244 	if (rgb->bridge) {
245 		ret = drm_bridge_attach(encoder, rgb->bridge, NULL, 0);
246 		if (ret) {
247 			dev_err(drm->dev, "Couldn't attach our bridge\n");
248 			goto err_cleanup_connector;
249 		}
250 	}
251 
252 	return 0;
253 
254 err_cleanup_connector:
255 	drm_encoder_cleanup(&rgb->encoder);
256 err_out:
257 	return ret;
258 }
259 EXPORT_SYMBOL(sun4i_rgb_init);
260