xref: /openbmc/linux/drivers/gpu/drm/tegra/rgb.c (revision 9a29f5fc)
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_bridge_connector.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 *pll_d_out0;
21 	struct clk *pll_d2_out0;
22 	struct clk *clk_parent;
23 	struct clk *clk;
24 };
25 
26 static inline struct tegra_rgb *to_rgb(struct tegra_output *output)
27 {
28 	return container_of(output, struct tegra_rgb, output);
29 }
30 
31 struct reg_entry {
32 	unsigned long offset;
33 	unsigned long value;
34 };
35 
36 static const struct reg_entry rgb_enable[] = {
37 	{ DC_COM_PIN_OUTPUT_ENABLE(0),   0x00000000 },
38 	{ DC_COM_PIN_OUTPUT_ENABLE(1),   0x00000000 },
39 	{ DC_COM_PIN_OUTPUT_ENABLE(2),   0x00000000 },
40 	{ DC_COM_PIN_OUTPUT_ENABLE(3),   0x00000000 },
41 	{ DC_COM_PIN_OUTPUT_POLARITY(0), 0x00000000 },
42 	{ DC_COM_PIN_OUTPUT_POLARITY(1), 0x01000000 },
43 	{ DC_COM_PIN_OUTPUT_POLARITY(2), 0x00000000 },
44 	{ DC_COM_PIN_OUTPUT_POLARITY(3), 0x00000000 },
45 	{ DC_COM_PIN_OUTPUT_DATA(0),     0x00000000 },
46 	{ DC_COM_PIN_OUTPUT_DATA(1),     0x00000000 },
47 	{ DC_COM_PIN_OUTPUT_DATA(2),     0x00000000 },
48 	{ DC_COM_PIN_OUTPUT_DATA(3),     0x00000000 },
49 	{ DC_COM_PIN_OUTPUT_SELECT(0),   0x00000000 },
50 	{ DC_COM_PIN_OUTPUT_SELECT(1),   0x00000000 },
51 	{ DC_COM_PIN_OUTPUT_SELECT(2),   0x00000000 },
52 	{ DC_COM_PIN_OUTPUT_SELECT(3),   0x00000000 },
53 	{ DC_COM_PIN_OUTPUT_SELECT(4),   0x00210222 },
54 	{ DC_COM_PIN_OUTPUT_SELECT(5),   0x00002200 },
55 	{ DC_COM_PIN_OUTPUT_SELECT(6),   0x00020000 },
56 };
57 
58 static const struct reg_entry rgb_disable[] = {
59 	{ DC_COM_PIN_OUTPUT_SELECT(6),   0x00000000 },
60 	{ DC_COM_PIN_OUTPUT_SELECT(5),   0x00000000 },
61 	{ DC_COM_PIN_OUTPUT_SELECT(4),   0x00000000 },
62 	{ DC_COM_PIN_OUTPUT_SELECT(3),   0x00000000 },
63 	{ DC_COM_PIN_OUTPUT_SELECT(2),   0x00000000 },
64 	{ DC_COM_PIN_OUTPUT_SELECT(1),   0x00000000 },
65 	{ DC_COM_PIN_OUTPUT_SELECT(0),   0x00000000 },
66 	{ DC_COM_PIN_OUTPUT_DATA(3),     0xaaaaaaaa },
67 	{ DC_COM_PIN_OUTPUT_DATA(2),     0xaaaaaaaa },
68 	{ DC_COM_PIN_OUTPUT_DATA(1),     0xaaaaaaaa },
69 	{ DC_COM_PIN_OUTPUT_DATA(0),     0xaaaaaaaa },
70 	{ DC_COM_PIN_OUTPUT_POLARITY(3), 0x00000000 },
71 	{ DC_COM_PIN_OUTPUT_POLARITY(2), 0x00000000 },
72 	{ DC_COM_PIN_OUTPUT_POLARITY(1), 0x00000000 },
73 	{ DC_COM_PIN_OUTPUT_POLARITY(0), 0x00000000 },
74 	{ DC_COM_PIN_OUTPUT_ENABLE(3),   0x55555555 },
75 	{ DC_COM_PIN_OUTPUT_ENABLE(2),   0x55555555 },
76 	{ DC_COM_PIN_OUTPUT_ENABLE(1),   0x55150005 },
77 	{ DC_COM_PIN_OUTPUT_ENABLE(0),   0x55555555 },
78 };
79 
80 static void tegra_dc_write_regs(struct tegra_dc *dc,
81 				const struct reg_entry *table,
82 				unsigned int num)
83 {
84 	unsigned int i;
85 
86 	for (i = 0; i < num; i++)
87 		tegra_dc_writel(dc, table[i].value, table[i].offset);
88 }
89 
90 static void tegra_rgb_encoder_disable(struct drm_encoder *encoder)
91 {
92 	struct tegra_output *output = encoder_to_output(encoder);
93 	struct tegra_rgb *rgb = to_rgb(output);
94 
95 	tegra_dc_write_regs(rgb->dc, rgb_disable, ARRAY_SIZE(rgb_disable));
96 	tegra_dc_commit(rgb->dc);
97 }
98 
99 static void tegra_rgb_encoder_enable(struct drm_encoder *encoder)
100 {
101 	struct tegra_output *output = encoder_to_output(encoder);
102 	struct tegra_rgb *rgb = to_rgb(output);
103 	u32 value;
104 
105 	tegra_dc_write_regs(rgb->dc, rgb_enable, ARRAY_SIZE(rgb_enable));
106 
107 	value = DE_SELECT_ACTIVE | DE_CONTROL_NORMAL;
108 	tegra_dc_writel(rgb->dc, value, DC_DISP_DATA_ENABLE_OPTIONS);
109 
110 	/* XXX: parameterize? */
111 	value = tegra_dc_readl(rgb->dc, DC_COM_PIN_OUTPUT_POLARITY(1));
112 	value &= ~LVS_OUTPUT_POLARITY_LOW;
113 	value &= ~LHS_OUTPUT_POLARITY_LOW;
114 	tegra_dc_writel(rgb->dc, value, DC_COM_PIN_OUTPUT_POLARITY(1));
115 
116 	/* XXX: parameterize? */
117 	value = DISP_DATA_FORMAT_DF1P1C | DISP_ALIGNMENT_MSB |
118 		DISP_ORDER_RED_BLUE;
119 	tegra_dc_writel(rgb->dc, value, DC_DISP_DISP_INTERFACE_CONTROL);
120 
121 	tegra_dc_commit(rgb->dc);
122 }
123 
124 static bool tegra_rgb_pll_rate_change_allowed(struct tegra_rgb *rgb)
125 {
126 	if (!rgb->pll_d2_out0)
127 		return false;
128 
129 	if (!clk_is_match(rgb->clk_parent, rgb->pll_d_out0) &&
130 	    !clk_is_match(rgb->clk_parent, rgb->pll_d2_out0))
131 		return false;
132 
133 	return true;
134 }
135 
136 static int
137 tegra_rgb_encoder_atomic_check(struct drm_encoder *encoder,
138 			       struct drm_crtc_state *crtc_state,
139 			       struct drm_connector_state *conn_state)
140 {
141 	struct tegra_output *output = encoder_to_output(encoder);
142 	struct tegra_dc *dc = to_tegra_dc(conn_state->crtc);
143 	unsigned long pclk = crtc_state->mode.clock * 1000;
144 	struct tegra_rgb *rgb = to_rgb(output);
145 	unsigned int div;
146 	int err;
147 
148 	/*
149 	 * We may not want to change the frequency of the parent clock, since
150 	 * it may be a parent for other peripherals. This is due to the fact
151 	 * that on Tegra20 there's only a single clock dedicated to display
152 	 * (pll_d_out0), whereas later generations have a second one that can
153 	 * be used to independently drive a second output (pll_d2_out0).
154 	 *
155 	 * As a way to support multiple outputs on Tegra20 as well, pll_p is
156 	 * typically used as the parent clock for the display controllers.
157 	 * But this comes at a cost: pll_p is the parent of several other
158 	 * peripherals, so its frequency shouldn't change out of the blue.
159 	 *
160 	 * The best we can do at this point is to use the shift clock divider
161 	 * and hope that the desired frequency can be matched (or at least
162 	 * matched sufficiently close that the panel will still work).
163 	 */
164 	if (tegra_rgb_pll_rate_change_allowed(rgb)) {
165 		/*
166 		 * Set display controller clock to x2 of PCLK in order to
167 		 * produce higher resolution pulse positions.
168 		 */
169 		div = 2;
170 		pclk *= 2;
171 	} else {
172 		div = ((clk_get_rate(rgb->clk) * 2) / pclk) - 2;
173 		pclk = 0;
174 	}
175 
176 	err = tegra_dc_state_setup_clock(dc, crtc_state, rgb->clk_parent,
177 					 pclk, div);
178 	if (err < 0) {
179 		dev_err(output->dev, "failed to setup CRTC state: %d\n", err);
180 		return err;
181 	}
182 
183 	return err;
184 }
185 
186 static const struct drm_encoder_helper_funcs tegra_rgb_encoder_helper_funcs = {
187 	.disable = tegra_rgb_encoder_disable,
188 	.enable = tegra_rgb_encoder_enable,
189 	.atomic_check = tegra_rgb_encoder_atomic_check,
190 };
191 
192 int tegra_dc_rgb_probe(struct tegra_dc *dc)
193 {
194 	struct device_node *np;
195 	struct tegra_rgb *rgb;
196 	int err;
197 
198 	np = of_get_child_by_name(dc->dev->of_node, "rgb");
199 	if (!np || !of_device_is_available(np))
200 		return -ENODEV;
201 
202 	rgb = devm_kzalloc(dc->dev, sizeof(*rgb), GFP_KERNEL);
203 	if (!rgb)
204 		return -ENOMEM;
205 
206 	rgb->output.dev = dc->dev;
207 	rgb->output.of_node = np;
208 	rgb->dc = dc;
209 
210 	err = tegra_output_probe(&rgb->output);
211 	if (err < 0)
212 		return err;
213 
214 	rgb->clk = devm_clk_get(dc->dev, NULL);
215 	if (IS_ERR(rgb->clk)) {
216 		dev_err(dc->dev, "failed to get clock\n");
217 		return PTR_ERR(rgb->clk);
218 	}
219 
220 	rgb->clk_parent = devm_clk_get(dc->dev, "parent");
221 	if (IS_ERR(rgb->clk_parent)) {
222 		dev_err(dc->dev, "failed to get parent clock\n");
223 		return PTR_ERR(rgb->clk_parent);
224 	}
225 
226 	err = clk_set_parent(rgb->clk, rgb->clk_parent);
227 	if (err < 0) {
228 		dev_err(dc->dev, "failed to set parent clock: %d\n", err);
229 		return err;
230 	}
231 
232 	rgb->pll_d_out0 = clk_get_sys(NULL, "pll_d_out0");
233 	if (IS_ERR(rgb->pll_d_out0)) {
234 		err = PTR_ERR(rgb->pll_d_out0);
235 		dev_err(dc->dev, "failed to get pll_d_out0: %d\n", err);
236 		return err;
237 	}
238 
239 	if (dc->soc->has_pll_d2_out0) {
240 		rgb->pll_d2_out0 = clk_get_sys(NULL, "pll_d2_out0");
241 		if (IS_ERR(rgb->pll_d2_out0)) {
242 			err = PTR_ERR(rgb->pll_d2_out0);
243 			dev_err(dc->dev, "failed to get pll_d2_out0: %d\n", err);
244 			return err;
245 		}
246 	}
247 
248 	dc->rgb = &rgb->output;
249 
250 	return 0;
251 }
252 
253 int tegra_dc_rgb_remove(struct tegra_dc *dc)
254 {
255 	struct tegra_rgb *rgb;
256 
257 	if (!dc->rgb)
258 		return 0;
259 
260 	rgb = to_rgb(dc->rgb);
261 	clk_put(rgb->pll_d2_out0);
262 	clk_put(rgb->pll_d_out0);
263 
264 	tegra_output_remove(dc->rgb);
265 	dc->rgb = NULL;
266 
267 	return 0;
268 }
269 
270 int tegra_dc_rgb_init(struct drm_device *drm, struct tegra_dc *dc)
271 {
272 	struct tegra_output *output = dc->rgb;
273 	struct drm_connector *connector;
274 	int err;
275 
276 	if (!dc->rgb)
277 		return -ENODEV;
278 
279 	drm_simple_encoder_init(drm, &output->encoder, DRM_MODE_ENCODER_LVDS);
280 	drm_encoder_helper_add(&output->encoder,
281 			       &tegra_rgb_encoder_helper_funcs);
282 
283 	/*
284 	 * Wrap directly-connected panel into DRM bridge in order to let
285 	 * DRM core to handle panel for us.
286 	 */
287 	if (output->panel) {
288 		output->bridge = devm_drm_panel_bridge_add(output->dev,
289 							   output->panel);
290 		if (IS_ERR(output->bridge)) {
291 			dev_err(output->dev,
292 				"failed to wrap panel into bridge: %pe\n",
293 				output->bridge);
294 			return PTR_ERR(output->bridge);
295 		}
296 
297 		output->panel = NULL;
298 	}
299 
300 	/*
301 	 * Tegra devices that have LVDS panel utilize LVDS encoder bridge
302 	 * for converting up to 28 LCD LVTTL lanes into 5/4 LVDS lanes that
303 	 * go to display panel's receiver.
304 	 *
305 	 * Encoder usually have a power-down control which needs to be enabled
306 	 * in order to transmit data to the panel.  Historically devices that
307 	 * use an older device-tree version didn't model the bridge, assuming
308 	 * that encoder is turned ON by default, while today's DRM allows us
309 	 * to model LVDS encoder properly.
310 	 *
311 	 * Newer device-trees utilize LVDS encoder bridge, which provides
312 	 * us with a connector and handles the display panel.
313 	 *
314 	 * For older device-trees we wrapped panel into the panel-bridge.
315 	 */
316 	if (output->bridge) {
317 		err = drm_bridge_attach(&output->encoder, output->bridge,
318 					NULL, DRM_BRIDGE_ATTACH_NO_CONNECTOR);
319 		if (err)
320 			return err;
321 
322 		connector = drm_bridge_connector_init(drm, &output->encoder);
323 		if (IS_ERR(connector)) {
324 			dev_err(output->dev,
325 				"failed to initialize bridge connector: %pe\n",
326 				connector);
327 			return PTR_ERR(connector);
328 		}
329 
330 		drm_connector_attach_encoder(connector, &output->encoder);
331 	}
332 
333 	err = tegra_output_init(drm, output);
334 	if (err < 0) {
335 		dev_err(output->dev, "failed to initialize output: %d\n", err);
336 		return err;
337 	}
338 
339 	/*
340 	 * Other outputs can be attached to either display controller. The RGB
341 	 * outputs are an exception and work only with their parent display
342 	 * controller.
343 	 */
344 	output->encoder.possible_crtcs = drm_crtc_mask(&dc->base);
345 
346 	return 0;
347 }
348 
349 int tegra_dc_rgb_exit(struct tegra_dc *dc)
350 {
351 	if (dc->rgb)
352 		tegra_output_exit(dc->rgb);
353 
354 	return 0;
355 }
356