xref: /openbmc/linux/drivers/gpu/drm/sun4i/sun4i_rgb.c (revision fb8d617f)
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 *
drm_connector_to_sun4i_rgb(struct drm_connector * connector)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 *
drm_encoder_to_sun4i_rgb(struct drm_encoder * encoder)40 drm_encoder_to_sun4i_rgb(struct drm_encoder *encoder)
41 {
42 	return container_of(encoder, struct sun4i_rgb,
43 			    encoder);
44 }
45 
sun4i_rgb_get_modes(struct drm_connector * connector)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 
sun4i_rgb_mode_valid(struct drm_encoder * crtc,const struct drm_display_mode * mode)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 const struct drm_connector_helper_funcs sun4i_rgb_con_helper_funcs = {
142 	.get_modes	= sun4i_rgb_get_modes,
143 };
144 
145 static void
sun4i_rgb_connector_destroy(struct drm_connector * connector)146 sun4i_rgb_connector_destroy(struct drm_connector *connector)
147 {
148 	drm_connector_cleanup(connector);
149 }
150 
151 static const struct drm_connector_funcs sun4i_rgb_con_funcs = {
152 	.fill_modes		= drm_helper_probe_single_connector_modes,
153 	.destroy		= sun4i_rgb_connector_destroy,
154 	.reset			= drm_atomic_helper_connector_reset,
155 	.atomic_duplicate_state	= drm_atomic_helper_connector_duplicate_state,
156 	.atomic_destroy_state	= drm_atomic_helper_connector_destroy_state,
157 };
158 
sun4i_rgb_encoder_enable(struct drm_encoder * encoder)159 static void sun4i_rgb_encoder_enable(struct drm_encoder *encoder)
160 {
161 	struct sun4i_rgb *rgb = drm_encoder_to_sun4i_rgb(encoder);
162 
163 	DRM_DEBUG_DRIVER("Enabling RGB output\n");
164 
165 	if (rgb->panel) {
166 		drm_panel_prepare(rgb->panel);
167 		drm_panel_enable(rgb->panel);
168 	}
169 }
170 
sun4i_rgb_encoder_disable(struct drm_encoder * encoder)171 static void sun4i_rgb_encoder_disable(struct drm_encoder *encoder)
172 {
173 	struct sun4i_rgb *rgb = drm_encoder_to_sun4i_rgb(encoder);
174 
175 	DRM_DEBUG_DRIVER("Disabling RGB output\n");
176 
177 	if (rgb->panel) {
178 		drm_panel_disable(rgb->panel);
179 		drm_panel_unprepare(rgb->panel);
180 	}
181 }
182 
183 static const struct drm_encoder_helper_funcs sun4i_rgb_enc_helper_funcs = {
184 	.disable	= sun4i_rgb_encoder_disable,
185 	.enable		= sun4i_rgb_encoder_enable,
186 	.mode_valid	= sun4i_rgb_mode_valid,
187 };
188 
sun4i_rgb_init(struct drm_device * drm,struct sun4i_tcon * tcon)189 int sun4i_rgb_init(struct drm_device *drm, struct sun4i_tcon *tcon)
190 {
191 	struct drm_encoder *encoder;
192 	struct sun4i_rgb *rgb;
193 	int ret;
194 
195 	rgb = devm_kzalloc(drm->dev, sizeof(*rgb), GFP_KERNEL);
196 	if (!rgb)
197 		return -ENOMEM;
198 	rgb->tcon = tcon;
199 	encoder = &rgb->encoder;
200 
201 	ret = drm_of_find_panel_or_bridge(tcon->dev->of_node, 1, 0,
202 					  &rgb->panel, &rgb->bridge);
203 	if (ret) {
204 		dev_info(drm->dev, "No panel or bridge found... RGB output disabled\n");
205 		return 0;
206 	}
207 
208 	drm_encoder_helper_add(&rgb->encoder,
209 			       &sun4i_rgb_enc_helper_funcs);
210 	ret = drm_simple_encoder_init(drm, &rgb->encoder,
211 				      DRM_MODE_ENCODER_NONE);
212 	if (ret) {
213 		dev_err(drm->dev, "Couldn't initialise the rgb encoder\n");
214 		goto err_out;
215 	}
216 
217 	/* The RGB encoder can only work with the TCON channel 0 */
218 	rgb->encoder.possible_crtcs = drm_crtc_mask(&tcon->crtc->crtc);
219 
220 	if (rgb->panel) {
221 		drm_connector_helper_add(&rgb->connector,
222 					 &sun4i_rgb_con_helper_funcs);
223 		ret = drm_connector_init(drm, &rgb->connector,
224 					 &sun4i_rgb_con_funcs,
225 					 DRM_MODE_CONNECTOR_Unknown);
226 		if (ret) {
227 			dev_err(drm->dev, "Couldn't initialise the rgb connector\n");
228 			goto err_cleanup_connector;
229 		}
230 
231 		drm_connector_attach_encoder(&rgb->connector,
232 						  &rgb->encoder);
233 	}
234 
235 	if (rgb->bridge) {
236 		ret = drm_bridge_attach(encoder, rgb->bridge, NULL, 0);
237 		if (ret)
238 			goto err_cleanup_connector;
239 	}
240 
241 	return 0;
242 
243 err_cleanup_connector:
244 	drm_encoder_cleanup(&rgb->encoder);
245 err_out:
246 	return ret;
247 }
248 EXPORT_SYMBOL(sun4i_rgb_init);
249