1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2016 Broadcom Limited
4  */
5 
6 /**
7  * DOC: VC4 DPI module
8  *
9  * The VC4 DPI hardware supports MIPI DPI type 4 and Nokia ViSSI
10  * signals.  On BCM2835, these can be routed out to GPIO0-27 with the
11  * ALT2 function.
12  */
13 
14 #include <drm/drm_atomic_helper.h>
15 #include <drm/drm_bridge.h>
16 #include <drm/drm_drv.h>
17 #include <drm/drm_edid.h>
18 #include <drm/drm_of.h>
19 #include <drm/drm_panel.h>
20 #include <drm/drm_probe_helper.h>
21 #include <drm/drm_simple_kms_helper.h>
22 #include <linux/clk.h>
23 #include <linux/component.h>
24 #include <linux/media-bus-format.h>
25 #include <linux/of_graph.h>
26 #include <linux/of_platform.h>
27 #include "vc4_drv.h"
28 #include "vc4_regs.h"
29 
30 #define DPI_C			0x00
31 # define DPI_OUTPUT_ENABLE_MODE		BIT(16)
32 
33 /* The order field takes the incoming 24 bit RGB from the pixel valve
34  * and shuffles the 3 channels.
35  */
36 # define DPI_ORDER_MASK			VC4_MASK(15, 14)
37 # define DPI_ORDER_SHIFT		14
38 # define DPI_ORDER_RGB			0
39 # define DPI_ORDER_BGR			1
40 # define DPI_ORDER_GRB			2
41 # define DPI_ORDER_BRG			3
42 
43 /* The format field takes the ORDER-shuffled pixel valve data and
44  * formats it onto the output lines.
45  */
46 # define DPI_FORMAT_MASK		VC4_MASK(13, 11)
47 # define DPI_FORMAT_SHIFT		11
48 /* This define is named in the hardware, but actually just outputs 0. */
49 # define DPI_FORMAT_9BIT_666_RGB	0
50 /* Outputs 00000000rrrrrggggggbbbbb */
51 # define DPI_FORMAT_16BIT_565_RGB_1	1
52 /* Outputs 000rrrrr00gggggg000bbbbb */
53 # define DPI_FORMAT_16BIT_565_RGB_2	2
54 /* Outputs 00rrrrr000gggggg00bbbbb0 */
55 # define DPI_FORMAT_16BIT_565_RGB_3	3
56 /* Outputs 000000rrrrrrggggggbbbbbb */
57 # define DPI_FORMAT_18BIT_666_RGB_1	4
58 /* Outputs 00rrrrrr00gggggg00bbbbbb */
59 # define DPI_FORMAT_18BIT_666_RGB_2	5
60 /* Outputs rrrrrrrrggggggggbbbbbbbb */
61 # define DPI_FORMAT_24BIT_888_RGB	6
62 
63 /* Reverses the polarity of the corresponding signal */
64 # define DPI_PIXEL_CLK_INVERT		BIT(10)
65 # define DPI_HSYNC_INVERT		BIT(9)
66 # define DPI_VSYNC_INVERT		BIT(8)
67 # define DPI_OUTPUT_ENABLE_INVERT	BIT(7)
68 
69 /* Outputs the signal the falling clock edge instead of rising. */
70 # define DPI_HSYNC_NEGATE		BIT(6)
71 # define DPI_VSYNC_NEGATE		BIT(5)
72 # define DPI_OUTPUT_ENABLE_NEGATE	BIT(4)
73 
74 /* Disables the signal */
75 # define DPI_HSYNC_DISABLE		BIT(3)
76 # define DPI_VSYNC_DISABLE		BIT(2)
77 # define DPI_OUTPUT_ENABLE_DISABLE	BIT(1)
78 
79 /* Power gate to the device, full reset at 0 -> 1 transition */
80 # define DPI_ENABLE			BIT(0)
81 
82 /* All other registers besides DPI_C return the ID */
83 #define DPI_ID			0x04
84 # define DPI_ID_VALUE		0x00647069
85 
86 /* General DPI hardware state. */
87 struct vc4_dpi {
88 	struct vc4_encoder encoder;
89 
90 	struct platform_device *pdev;
91 
92 	void __iomem *regs;
93 
94 	struct clk *pixel_clock;
95 	struct clk *core_clock;
96 
97 	struct debugfs_regset32 regset;
98 };
99 
100 static inline struct vc4_dpi *
to_vc4_dpi(struct drm_encoder * encoder)101 to_vc4_dpi(struct drm_encoder *encoder)
102 {
103 	return container_of(encoder, struct vc4_dpi, encoder.base);
104 }
105 
106 #define DPI_READ(offset) readl(dpi->regs + (offset))
107 #define DPI_WRITE(offset, val) writel(val, dpi->regs + (offset))
108 
109 static const struct debugfs_reg32 dpi_regs[] = {
110 	VC4_REG32(DPI_C),
111 	VC4_REG32(DPI_ID),
112 };
113 
vc4_dpi_encoder_disable(struct drm_encoder * encoder)114 static void vc4_dpi_encoder_disable(struct drm_encoder *encoder)
115 {
116 	struct drm_device *dev = encoder->dev;
117 	struct vc4_dpi *dpi = to_vc4_dpi(encoder);
118 	int idx;
119 
120 	if (!drm_dev_enter(dev, &idx))
121 		return;
122 
123 	clk_disable_unprepare(dpi->pixel_clock);
124 
125 	drm_dev_exit(idx);
126 }
127 
vc4_dpi_encoder_enable(struct drm_encoder * encoder)128 static void vc4_dpi_encoder_enable(struct drm_encoder *encoder)
129 {
130 	struct drm_device *dev = encoder->dev;
131 	struct drm_display_mode *mode = &encoder->crtc->mode;
132 	struct vc4_dpi *dpi = to_vc4_dpi(encoder);
133 	struct drm_connector_list_iter conn_iter;
134 	struct drm_connector *connector = NULL, *connector_scan;
135 	u32 dpi_c = DPI_ENABLE;
136 	int idx;
137 	int ret;
138 
139 	/* Look up the connector attached to DPI so we can get the
140 	 * bus_format.  Ideally the bridge would tell us the
141 	 * bus_format we want, but it doesn't yet, so assume that it's
142 	 * uniform throughout the bridge chain.
143 	 */
144 	drm_connector_list_iter_begin(dev, &conn_iter);
145 	drm_for_each_connector_iter(connector_scan, &conn_iter) {
146 		if (connector_scan->encoder == encoder) {
147 			connector = connector_scan;
148 			break;
149 		}
150 	}
151 	drm_connector_list_iter_end(&conn_iter);
152 
153 	/* Default to 24bit if no connector or format found. */
154 	dpi_c |= VC4_SET_FIELD(DPI_FORMAT_24BIT_888_RGB, DPI_FORMAT);
155 
156 	if (connector) {
157 		if (connector->display_info.num_bus_formats) {
158 			u32 bus_format = connector->display_info.bus_formats[0];
159 
160 			dpi_c &= ~DPI_FORMAT_MASK;
161 
162 			switch (bus_format) {
163 			case MEDIA_BUS_FMT_RGB888_1X24:
164 				dpi_c |= VC4_SET_FIELD(DPI_FORMAT_24BIT_888_RGB,
165 						       DPI_FORMAT);
166 				break;
167 			case MEDIA_BUS_FMT_BGR888_1X24:
168 				dpi_c |= VC4_SET_FIELD(DPI_FORMAT_24BIT_888_RGB,
169 						       DPI_FORMAT);
170 				dpi_c |= VC4_SET_FIELD(DPI_ORDER_BGR,
171 						       DPI_ORDER);
172 				break;
173 			case MEDIA_BUS_FMT_RGB666_1X24_CPADHI:
174 				dpi_c |= VC4_SET_FIELD(DPI_FORMAT_18BIT_666_RGB_2,
175 						       DPI_FORMAT);
176 				break;
177 			case MEDIA_BUS_FMT_RGB666_1X18:
178 				dpi_c |= VC4_SET_FIELD(DPI_FORMAT_18BIT_666_RGB_1,
179 						       DPI_FORMAT);
180 				break;
181 			case MEDIA_BUS_FMT_RGB565_1X16:
182 				dpi_c |= VC4_SET_FIELD(DPI_FORMAT_16BIT_565_RGB_3,
183 						       DPI_FORMAT);
184 				break;
185 			default:
186 				DRM_ERROR("Unknown media bus format %d\n",
187 					  bus_format);
188 				break;
189 			}
190 		}
191 
192 		if (connector->display_info.bus_flags & DRM_BUS_FLAG_PIXDATA_DRIVE_NEGEDGE)
193 			dpi_c |= DPI_PIXEL_CLK_INVERT;
194 
195 		if (connector->display_info.bus_flags & DRM_BUS_FLAG_DE_LOW)
196 			dpi_c |= DPI_OUTPUT_ENABLE_INVERT;
197 	}
198 
199 	if (mode->flags & DRM_MODE_FLAG_CSYNC) {
200 		if (mode->flags & DRM_MODE_FLAG_NCSYNC)
201 			dpi_c |= DPI_OUTPUT_ENABLE_INVERT;
202 	} else {
203 		dpi_c |= DPI_OUTPUT_ENABLE_MODE;
204 
205 		if (mode->flags & DRM_MODE_FLAG_NHSYNC)
206 			dpi_c |= DPI_HSYNC_INVERT;
207 		else if (!(mode->flags & DRM_MODE_FLAG_PHSYNC))
208 			dpi_c |= DPI_HSYNC_DISABLE;
209 
210 		if (mode->flags & DRM_MODE_FLAG_NVSYNC)
211 			dpi_c |= DPI_VSYNC_INVERT;
212 		else if (!(mode->flags & DRM_MODE_FLAG_PVSYNC))
213 			dpi_c |= DPI_VSYNC_DISABLE;
214 	}
215 
216 	if (!drm_dev_enter(dev, &idx))
217 		return;
218 
219 	DPI_WRITE(DPI_C, dpi_c);
220 
221 	ret = clk_set_rate(dpi->pixel_clock, mode->clock * 1000);
222 	if (ret)
223 		DRM_ERROR("Failed to set clock rate: %d\n", ret);
224 
225 	ret = clk_prepare_enable(dpi->pixel_clock);
226 	if (ret)
227 		DRM_ERROR("Failed to set clock rate: %d\n", ret);
228 
229 	drm_dev_exit(idx);
230 }
231 
vc4_dpi_encoder_mode_valid(struct drm_encoder * encoder,const struct drm_display_mode * mode)232 static enum drm_mode_status vc4_dpi_encoder_mode_valid(struct drm_encoder *encoder,
233 						       const struct drm_display_mode *mode)
234 {
235 	if (mode->flags & DRM_MODE_FLAG_INTERLACE)
236 		return MODE_NO_INTERLACE;
237 
238 	return MODE_OK;
239 }
240 
241 static const struct drm_encoder_helper_funcs vc4_dpi_encoder_helper_funcs = {
242 	.disable = vc4_dpi_encoder_disable,
243 	.enable = vc4_dpi_encoder_enable,
244 	.mode_valid = vc4_dpi_encoder_mode_valid,
245 };
246 
vc4_dpi_late_register(struct drm_encoder * encoder)247 static int vc4_dpi_late_register(struct drm_encoder *encoder)
248 {
249 	struct drm_device *drm = encoder->dev;
250 	struct vc4_dpi *dpi = to_vc4_dpi(encoder);
251 	int ret;
252 
253 	ret = vc4_debugfs_add_regset32(drm->primary, "dpi_regs", &dpi->regset);
254 	if (ret)
255 		return ret;
256 
257 	return 0;
258 }
259 
260 static const struct drm_encoder_funcs vc4_dpi_encoder_funcs = {
261 	.late_register = vc4_dpi_late_register,
262 };
263 
264 static const struct of_device_id vc4_dpi_dt_match[] = {
265 	{ .compatible = "brcm,bcm2835-dpi", .data = NULL },
266 	{}
267 };
268 
269 /* Sets up the next link in the display chain, whether it's a panel or
270  * a bridge.
271  */
vc4_dpi_init_bridge(struct vc4_dpi * dpi)272 static int vc4_dpi_init_bridge(struct vc4_dpi *dpi)
273 {
274 	struct drm_device *drm = dpi->encoder.base.dev;
275 	struct device *dev = &dpi->pdev->dev;
276 	struct drm_bridge *bridge;
277 
278 	bridge = drmm_of_get_bridge(drm, dev->of_node, 0, 0);
279 	if (IS_ERR(bridge)) {
280 		/* If nothing was connected in the DT, that's not an
281 		 * error.
282 		 */
283 		if (PTR_ERR(bridge) == -ENODEV)
284 			return 0;
285 		else
286 			return PTR_ERR(bridge);
287 	}
288 
289 	return drm_bridge_attach(&dpi->encoder.base, bridge, NULL, 0);
290 }
291 
vc4_dpi_disable_clock(void * ptr)292 static void vc4_dpi_disable_clock(void *ptr)
293 {
294 	struct vc4_dpi *dpi = ptr;
295 
296 	clk_disable_unprepare(dpi->core_clock);
297 }
298 
vc4_dpi_bind(struct device * dev,struct device * master,void * data)299 static int vc4_dpi_bind(struct device *dev, struct device *master, void *data)
300 {
301 	struct platform_device *pdev = to_platform_device(dev);
302 	struct drm_device *drm = dev_get_drvdata(master);
303 	struct vc4_dpi *dpi;
304 	int ret;
305 
306 	dpi = drmm_kzalloc(drm, sizeof(*dpi), GFP_KERNEL);
307 	if (!dpi)
308 		return -ENOMEM;
309 
310 	dpi->encoder.type = VC4_ENCODER_TYPE_DPI;
311 	dpi->pdev = pdev;
312 	dpi->regs = vc4_ioremap_regs(pdev, 0);
313 	if (IS_ERR(dpi->regs))
314 		return PTR_ERR(dpi->regs);
315 	dpi->regset.base = dpi->regs;
316 	dpi->regset.regs = dpi_regs;
317 	dpi->regset.nregs = ARRAY_SIZE(dpi_regs);
318 
319 	if (DPI_READ(DPI_ID) != DPI_ID_VALUE) {
320 		dev_err(dev, "Port returned 0x%08x for ID instead of 0x%08x\n",
321 			DPI_READ(DPI_ID), DPI_ID_VALUE);
322 		return -ENODEV;
323 	}
324 
325 	dpi->core_clock = devm_clk_get(dev, "core");
326 	if (IS_ERR(dpi->core_clock)) {
327 		ret = PTR_ERR(dpi->core_clock);
328 		if (ret != -EPROBE_DEFER)
329 			DRM_ERROR("Failed to get core clock: %d\n", ret);
330 		return ret;
331 	}
332 
333 	dpi->pixel_clock = devm_clk_get(dev, "pixel");
334 	if (IS_ERR(dpi->pixel_clock)) {
335 		ret = PTR_ERR(dpi->pixel_clock);
336 		if (ret != -EPROBE_DEFER)
337 			DRM_ERROR("Failed to get pixel clock: %d\n", ret);
338 		return ret;
339 	}
340 
341 	ret = clk_prepare_enable(dpi->core_clock);
342 	if (ret) {
343 		DRM_ERROR("Failed to turn on core clock: %d\n", ret);
344 		return ret;
345 	}
346 
347 	ret = devm_add_action_or_reset(dev, vc4_dpi_disable_clock, dpi);
348 	if (ret)
349 		return ret;
350 
351 	ret = drmm_encoder_init(drm, &dpi->encoder.base,
352 				&vc4_dpi_encoder_funcs,
353 				DRM_MODE_ENCODER_DPI,
354 				NULL);
355 	if (ret)
356 		return ret;
357 
358 	drm_encoder_helper_add(&dpi->encoder.base, &vc4_dpi_encoder_helper_funcs);
359 
360 	ret = vc4_dpi_init_bridge(dpi);
361 	if (ret)
362 		return ret;
363 
364 	dev_set_drvdata(dev, dpi);
365 
366 	return 0;
367 }
368 
369 static const struct component_ops vc4_dpi_ops = {
370 	.bind   = vc4_dpi_bind,
371 };
372 
vc4_dpi_dev_probe(struct platform_device * pdev)373 static int vc4_dpi_dev_probe(struct platform_device *pdev)
374 {
375 	return component_add(&pdev->dev, &vc4_dpi_ops);
376 }
377 
vc4_dpi_dev_remove(struct platform_device * pdev)378 static int vc4_dpi_dev_remove(struct platform_device *pdev)
379 {
380 	component_del(&pdev->dev, &vc4_dpi_ops);
381 	return 0;
382 }
383 
384 struct platform_driver vc4_dpi_driver = {
385 	.probe = vc4_dpi_dev_probe,
386 	.remove = vc4_dpi_dev_remove,
387 	.driver = {
388 		.name = "vc4_dpi",
389 		.of_match_table = vc4_dpi_dt_match,
390 	},
391 };
392