xref: /openbmc/linux/drivers/gpu/drm/tegra/rgb.c (revision 95298d63)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2012 Avionic Design GmbH
4  * Copyright (C) 2012 NVIDIA CORPORATION.  All rights reserved.
5  */
6 
7 #include <linux/clk.h>
8 
9 #include <drm/drm_atomic_helper.h>
10 #include <drm/drm_panel.h>
11 #include <drm/drm_simple_kms_helper.h>
12 
13 #include "drm.h"
14 #include "dc.h"
15 
16 struct tegra_rgb {
17 	struct tegra_output output;
18 	struct tegra_dc *dc;
19 
20 	struct clk *clk_parent;
21 	struct clk *clk;
22 };
23 
24 static inline struct tegra_rgb *to_rgb(struct tegra_output *output)
25 {
26 	return container_of(output, struct tegra_rgb, output);
27 }
28 
29 struct reg_entry {
30 	unsigned long offset;
31 	unsigned long value;
32 };
33 
34 static const struct reg_entry rgb_enable[] = {
35 	{ DC_COM_PIN_OUTPUT_ENABLE(0),   0x00000000 },
36 	{ DC_COM_PIN_OUTPUT_ENABLE(1),   0x00000000 },
37 	{ DC_COM_PIN_OUTPUT_ENABLE(2),   0x00000000 },
38 	{ DC_COM_PIN_OUTPUT_ENABLE(3),   0x00000000 },
39 	{ DC_COM_PIN_OUTPUT_POLARITY(0), 0x00000000 },
40 	{ DC_COM_PIN_OUTPUT_POLARITY(1), 0x01000000 },
41 	{ DC_COM_PIN_OUTPUT_POLARITY(2), 0x00000000 },
42 	{ DC_COM_PIN_OUTPUT_POLARITY(3), 0x00000000 },
43 	{ DC_COM_PIN_OUTPUT_DATA(0),     0x00000000 },
44 	{ DC_COM_PIN_OUTPUT_DATA(1),     0x00000000 },
45 	{ DC_COM_PIN_OUTPUT_DATA(2),     0x00000000 },
46 	{ DC_COM_PIN_OUTPUT_DATA(3),     0x00000000 },
47 	{ DC_COM_PIN_OUTPUT_SELECT(0),   0x00000000 },
48 	{ DC_COM_PIN_OUTPUT_SELECT(1),   0x00000000 },
49 	{ DC_COM_PIN_OUTPUT_SELECT(2),   0x00000000 },
50 	{ DC_COM_PIN_OUTPUT_SELECT(3),   0x00000000 },
51 	{ DC_COM_PIN_OUTPUT_SELECT(4),   0x00210222 },
52 	{ DC_COM_PIN_OUTPUT_SELECT(5),   0x00002200 },
53 	{ DC_COM_PIN_OUTPUT_SELECT(6),   0x00020000 },
54 };
55 
56 static const struct reg_entry rgb_disable[] = {
57 	{ DC_COM_PIN_OUTPUT_SELECT(6),   0x00000000 },
58 	{ DC_COM_PIN_OUTPUT_SELECT(5),   0x00000000 },
59 	{ DC_COM_PIN_OUTPUT_SELECT(4),   0x00000000 },
60 	{ DC_COM_PIN_OUTPUT_SELECT(3),   0x00000000 },
61 	{ DC_COM_PIN_OUTPUT_SELECT(2),   0x00000000 },
62 	{ DC_COM_PIN_OUTPUT_SELECT(1),   0x00000000 },
63 	{ DC_COM_PIN_OUTPUT_SELECT(0),   0x00000000 },
64 	{ DC_COM_PIN_OUTPUT_DATA(3),     0xaaaaaaaa },
65 	{ DC_COM_PIN_OUTPUT_DATA(2),     0xaaaaaaaa },
66 	{ DC_COM_PIN_OUTPUT_DATA(1),     0xaaaaaaaa },
67 	{ DC_COM_PIN_OUTPUT_DATA(0),     0xaaaaaaaa },
68 	{ DC_COM_PIN_OUTPUT_POLARITY(3), 0x00000000 },
69 	{ DC_COM_PIN_OUTPUT_POLARITY(2), 0x00000000 },
70 	{ DC_COM_PIN_OUTPUT_POLARITY(1), 0x00000000 },
71 	{ DC_COM_PIN_OUTPUT_POLARITY(0), 0x00000000 },
72 	{ DC_COM_PIN_OUTPUT_ENABLE(3),   0x55555555 },
73 	{ DC_COM_PIN_OUTPUT_ENABLE(2),   0x55555555 },
74 	{ DC_COM_PIN_OUTPUT_ENABLE(1),   0x55150005 },
75 	{ DC_COM_PIN_OUTPUT_ENABLE(0),   0x55555555 },
76 };
77 
78 static void tegra_dc_write_regs(struct tegra_dc *dc,
79 				const struct reg_entry *table,
80 				unsigned int num)
81 {
82 	unsigned int i;
83 
84 	for (i = 0; i < num; i++)
85 		tegra_dc_writel(dc, table[i].value, table[i].offset);
86 }
87 
88 static const struct drm_connector_funcs tegra_rgb_connector_funcs = {
89 	.reset = drm_atomic_helper_connector_reset,
90 	.detect = tegra_output_connector_detect,
91 	.fill_modes = drm_helper_probe_single_connector_modes,
92 	.destroy = tegra_output_connector_destroy,
93 	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
94 	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
95 };
96 
97 static enum drm_mode_status
98 tegra_rgb_connector_mode_valid(struct drm_connector *connector,
99 			       struct drm_display_mode *mode)
100 {
101 	/*
102 	 * FIXME: For now, always assume that the mode is okay. There are
103 	 * unresolved issues with clk_round_rate(), which doesn't always
104 	 * reliably report whether a frequency can be set or not.
105 	 */
106 	return MODE_OK;
107 }
108 
109 static const struct drm_connector_helper_funcs tegra_rgb_connector_helper_funcs = {
110 	.get_modes = tegra_output_connector_get_modes,
111 	.mode_valid = tegra_rgb_connector_mode_valid,
112 };
113 
114 static void tegra_rgb_encoder_disable(struct drm_encoder *encoder)
115 {
116 	struct tegra_output *output = encoder_to_output(encoder);
117 	struct tegra_rgb *rgb = to_rgb(output);
118 
119 	if (output->panel)
120 		drm_panel_disable(output->panel);
121 
122 	tegra_dc_write_regs(rgb->dc, rgb_disable, ARRAY_SIZE(rgb_disable));
123 	tegra_dc_commit(rgb->dc);
124 
125 	if (output->panel)
126 		drm_panel_unprepare(output->panel);
127 }
128 
129 static void tegra_rgb_encoder_enable(struct drm_encoder *encoder)
130 {
131 	struct tegra_output *output = encoder_to_output(encoder);
132 	struct tegra_rgb *rgb = to_rgb(output);
133 	u32 value;
134 
135 	if (output->panel)
136 		drm_panel_prepare(output->panel);
137 
138 	tegra_dc_write_regs(rgb->dc, rgb_enable, ARRAY_SIZE(rgb_enable));
139 
140 	value = DE_SELECT_ACTIVE | DE_CONTROL_NORMAL;
141 	tegra_dc_writel(rgb->dc, value, DC_DISP_DATA_ENABLE_OPTIONS);
142 
143 	/* XXX: parameterize? */
144 	value = tegra_dc_readl(rgb->dc, DC_COM_PIN_OUTPUT_POLARITY(1));
145 	value &= ~LVS_OUTPUT_POLARITY_LOW;
146 	value &= ~LHS_OUTPUT_POLARITY_LOW;
147 	tegra_dc_writel(rgb->dc, value, DC_COM_PIN_OUTPUT_POLARITY(1));
148 
149 	/* XXX: parameterize? */
150 	value = DISP_DATA_FORMAT_DF1P1C | DISP_ALIGNMENT_MSB |
151 		DISP_ORDER_RED_BLUE;
152 	tegra_dc_writel(rgb->dc, value, DC_DISP_DISP_INTERFACE_CONTROL);
153 
154 	/* XXX: parameterize? */
155 	value = SC0_H_QUALIFIER_NONE | SC1_H_QUALIFIER_NONE;
156 	tegra_dc_writel(rgb->dc, value, DC_DISP_SHIFT_CLOCK_OPTIONS);
157 
158 	tegra_dc_commit(rgb->dc);
159 
160 	if (output->panel)
161 		drm_panel_enable(output->panel);
162 }
163 
164 static int
165 tegra_rgb_encoder_atomic_check(struct drm_encoder *encoder,
166 			       struct drm_crtc_state *crtc_state,
167 			       struct drm_connector_state *conn_state)
168 {
169 	struct tegra_output *output = encoder_to_output(encoder);
170 	struct tegra_dc *dc = to_tegra_dc(conn_state->crtc);
171 	unsigned long pclk = crtc_state->mode.clock * 1000;
172 	struct tegra_rgb *rgb = to_rgb(output);
173 	unsigned int div;
174 	int err;
175 
176 	/*
177 	 * We may not want to change the frequency of the parent clock, since
178 	 * it may be a parent for other peripherals. This is due to the fact
179 	 * that on Tegra20 there's only a single clock dedicated to display
180 	 * (pll_d_out0), whereas later generations have a second one that can
181 	 * be used to independently drive a second output (pll_d2_out0).
182 	 *
183 	 * As a way to support multiple outputs on Tegra20 as well, pll_p is
184 	 * typically used as the parent clock for the display controllers.
185 	 * But this comes at a cost: pll_p is the parent of several other
186 	 * peripherals, so its frequency shouldn't change out of the blue.
187 	 *
188 	 * The best we can do at this point is to use the shift clock divider
189 	 * and hope that the desired frequency can be matched (or at least
190 	 * matched sufficiently close that the panel will still work).
191 	 */
192 	div = ((clk_get_rate(rgb->clk) * 2) / pclk) - 2;
193 	pclk = 0;
194 
195 	err = tegra_dc_state_setup_clock(dc, crtc_state, rgb->clk_parent,
196 					 pclk, div);
197 	if (err < 0) {
198 		dev_err(output->dev, "failed to setup CRTC state: %d\n", err);
199 		return err;
200 	}
201 
202 	return err;
203 }
204 
205 static const struct drm_encoder_helper_funcs tegra_rgb_encoder_helper_funcs = {
206 	.disable = tegra_rgb_encoder_disable,
207 	.enable = tegra_rgb_encoder_enable,
208 	.atomic_check = tegra_rgb_encoder_atomic_check,
209 };
210 
211 int tegra_dc_rgb_probe(struct tegra_dc *dc)
212 {
213 	struct device_node *np;
214 	struct tegra_rgb *rgb;
215 	int err;
216 
217 	np = of_get_child_by_name(dc->dev->of_node, "rgb");
218 	if (!np || !of_device_is_available(np))
219 		return -ENODEV;
220 
221 	rgb = devm_kzalloc(dc->dev, sizeof(*rgb), GFP_KERNEL);
222 	if (!rgb)
223 		return -ENOMEM;
224 
225 	rgb->output.dev = dc->dev;
226 	rgb->output.of_node = np;
227 	rgb->dc = dc;
228 
229 	err = tegra_output_probe(&rgb->output);
230 	if (err < 0)
231 		return err;
232 
233 	rgb->clk = devm_clk_get(dc->dev, NULL);
234 	if (IS_ERR(rgb->clk)) {
235 		dev_err(dc->dev, "failed to get clock\n");
236 		return PTR_ERR(rgb->clk);
237 	}
238 
239 	rgb->clk_parent = devm_clk_get(dc->dev, "parent");
240 	if (IS_ERR(rgb->clk_parent)) {
241 		dev_err(dc->dev, "failed to get parent clock\n");
242 		return PTR_ERR(rgb->clk_parent);
243 	}
244 
245 	err = clk_set_parent(rgb->clk, rgb->clk_parent);
246 	if (err < 0) {
247 		dev_err(dc->dev, "failed to set parent clock: %d\n", err);
248 		return err;
249 	}
250 
251 	dc->rgb = &rgb->output;
252 
253 	return 0;
254 }
255 
256 int tegra_dc_rgb_remove(struct tegra_dc *dc)
257 {
258 	if (!dc->rgb)
259 		return 0;
260 
261 	tegra_output_remove(dc->rgb);
262 	dc->rgb = NULL;
263 
264 	return 0;
265 }
266 
267 int tegra_dc_rgb_init(struct drm_device *drm, struct tegra_dc *dc)
268 {
269 	struct tegra_output *output = dc->rgb;
270 	int err;
271 
272 	if (!dc->rgb)
273 		return -ENODEV;
274 
275 	drm_connector_init(drm, &output->connector, &tegra_rgb_connector_funcs,
276 			   DRM_MODE_CONNECTOR_LVDS);
277 	drm_connector_helper_add(&output->connector,
278 				 &tegra_rgb_connector_helper_funcs);
279 	output->connector.dpms = DRM_MODE_DPMS_OFF;
280 
281 	drm_simple_encoder_init(drm, &output->encoder, DRM_MODE_ENCODER_LVDS);
282 	drm_encoder_helper_add(&output->encoder,
283 			       &tegra_rgb_encoder_helper_funcs);
284 
285 	drm_connector_attach_encoder(&output->connector,
286 					  &output->encoder);
287 	drm_connector_register(&output->connector);
288 
289 	err = tegra_output_init(drm, output);
290 	if (err < 0) {
291 		dev_err(output->dev, "failed to initialize output: %d\n", err);
292 		return err;
293 	}
294 
295 	/*
296 	 * Other outputs can be attached to either display controller. The RGB
297 	 * outputs are an exception and work only with their parent display
298 	 * controller.
299 	 */
300 	output->encoder.possible_crtcs = drm_crtc_mask(&dc->base);
301 
302 	return 0;
303 }
304 
305 int tegra_dc_rgb_exit(struct tegra_dc *dc)
306 {
307 	if (dc->rgb)
308 		tegra_output_exit(dc->rgb);
309 
310 	return 0;
311 }
312