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_edid.h>
17#include <drm/drm_of.h>
18#include <drm/drm_panel.h>
19#include <drm/drm_probe_helper.h>
20#include <drm/drm_simple_kms_helper.h>
21#include <linux/clk.h>
22#include <linux/component.h>
23#include <linux/of_graph.h>
24#include <linux/of_platform.h>
25#include "vc4_drv.h"
26#include "vc4_regs.h"
27
28#define DPI_C			0x00
29# define DPI_OUTPUT_ENABLE_MODE		BIT(16)
30
31/* The order field takes the incoming 24 bit RGB from the pixel valve
32 * and shuffles the 3 channels.
33 */
34# define DPI_ORDER_MASK			VC4_MASK(15, 14)
35# define DPI_ORDER_SHIFT		14
36# define DPI_ORDER_RGB			0
37# define DPI_ORDER_BGR			1
38# define DPI_ORDER_GRB			2
39# define DPI_ORDER_BRG			3
40
41/* The format field takes the ORDER-shuffled pixel valve data and
42 * formats it onto the output lines.
43 */
44# define DPI_FORMAT_MASK		VC4_MASK(13, 11)
45# define DPI_FORMAT_SHIFT		11
46/* This define is named in the hardware, but actually just outputs 0. */
47# define DPI_FORMAT_9BIT_666_RGB	0
48/* Outputs 00000000rrrrrggggggbbbbb */
49# define DPI_FORMAT_16BIT_565_RGB_1	1
50/* Outputs 000rrrrr00gggggg000bbbbb */
51# define DPI_FORMAT_16BIT_565_RGB_2	2
52/* Outputs 00rrrrr000gggggg00bbbbb0 */
53# define DPI_FORMAT_16BIT_565_RGB_3	3
54/* Outputs 000000rrrrrrggggggbbbbbb */
55# define DPI_FORMAT_18BIT_666_RGB_1	4
56/* Outputs 00rrrrrr00gggggg00bbbbbb */
57# define DPI_FORMAT_18BIT_666_RGB_2	5
58/* Outputs rrrrrrrrggggggggbbbbbbbb */
59# define DPI_FORMAT_24BIT_888_RGB	6
60
61/* Reverses the polarity of the corresponding signal */
62# define DPI_PIXEL_CLK_INVERT		BIT(10)
63# define DPI_HSYNC_INVERT		BIT(9)
64# define DPI_VSYNC_INVERT		BIT(8)
65# define DPI_OUTPUT_ENABLE_INVERT	BIT(7)
66
67/* Outputs the signal the falling clock edge instead of rising. */
68# define DPI_HSYNC_NEGATE		BIT(6)
69# define DPI_VSYNC_NEGATE		BIT(5)
70# define DPI_OUTPUT_ENABLE_NEGATE	BIT(4)
71
72/* Disables the signal */
73# define DPI_HSYNC_DISABLE		BIT(3)
74# define DPI_VSYNC_DISABLE		BIT(2)
75# define DPI_OUTPUT_ENABLE_DISABLE	BIT(1)
76
77/* Power gate to the device, full reset at 0 -> 1 transition */
78# define DPI_ENABLE			BIT(0)
79
80/* All other registers besides DPI_C return the ID */
81#define DPI_ID			0x04
82# define DPI_ID_VALUE		0x00647069
83
84/* General DPI hardware state. */
85struct vc4_dpi {
86	struct platform_device *pdev;
87
88	struct drm_encoder *encoder;
89
90	void __iomem *regs;
91
92	struct clk *pixel_clock;
93	struct clk *core_clock;
94
95	struct debugfs_regset32 regset;
96};
97
98#define DPI_READ(offset) readl(dpi->regs + (offset))
99#define DPI_WRITE(offset, val) writel(val, dpi->regs + (offset))
100
101/* VC4 DPI encoder KMS struct */
102struct vc4_dpi_encoder {
103	struct vc4_encoder base;
104	struct vc4_dpi *dpi;
105};
106
107static inline struct vc4_dpi_encoder *
108to_vc4_dpi_encoder(struct drm_encoder *encoder)
109{
110	return container_of(encoder, struct vc4_dpi_encoder, base.base);
111}
112
113static const struct debugfs_reg32 dpi_regs[] = {
114	VC4_REG32(DPI_C),
115	VC4_REG32(DPI_ID),
116};
117
118static void vc4_dpi_encoder_disable(struct drm_encoder *encoder)
119{
120	struct vc4_dpi_encoder *vc4_encoder = to_vc4_dpi_encoder(encoder);
121	struct vc4_dpi *dpi = vc4_encoder->dpi;
122
123	clk_disable_unprepare(dpi->pixel_clock);
124}
125
126static void vc4_dpi_encoder_enable(struct drm_encoder *encoder)
127{
128	struct drm_device *dev = encoder->dev;
129	struct drm_display_mode *mode = &encoder->crtc->mode;
130	struct vc4_dpi_encoder *vc4_encoder = to_vc4_dpi_encoder(encoder);
131	struct vc4_dpi *dpi = vc4_encoder->dpi;
132	struct drm_connector_list_iter conn_iter;
133	struct drm_connector *connector = NULL, *connector_scan;
134	u32 dpi_c = DPI_ENABLE | DPI_OUTPUT_ENABLE_MODE;
135	int ret;
136
137	/* Look up the connector attached to DPI so we can get the
138	 * bus_format.  Ideally the bridge would tell us the
139	 * bus_format we want, but it doesn't yet, so assume that it's
140	 * uniform throughout the bridge chain.
141	 */
142	drm_connector_list_iter_begin(dev, &conn_iter);
143	drm_for_each_connector_iter(connector_scan, &conn_iter) {
144		if (connector_scan->encoder == encoder) {
145			connector = connector_scan;
146			break;
147		}
148	}
149	drm_connector_list_iter_end(&conn_iter);
150
151	if (connector) {
152		if (connector->display_info.num_bus_formats) {
153			u32 bus_format = connector->display_info.bus_formats[0];
154
155			switch (bus_format) {
156			case MEDIA_BUS_FMT_RGB888_1X24:
157				dpi_c |= VC4_SET_FIELD(DPI_FORMAT_24BIT_888_RGB,
158						       DPI_FORMAT);
159				break;
160			case MEDIA_BUS_FMT_BGR888_1X24:
161				dpi_c |= VC4_SET_FIELD(DPI_FORMAT_24BIT_888_RGB,
162						       DPI_FORMAT);
163				dpi_c |= VC4_SET_FIELD(DPI_ORDER_BGR,
164						       DPI_ORDER);
165				break;
166			case MEDIA_BUS_FMT_RGB666_1X24_CPADHI:
167				dpi_c |= VC4_SET_FIELD(DPI_FORMAT_18BIT_666_RGB_2,
168						       DPI_FORMAT);
169				break;
170			case MEDIA_BUS_FMT_RGB666_1X18:
171				dpi_c |= VC4_SET_FIELD(DPI_FORMAT_18BIT_666_RGB_1,
172						       DPI_FORMAT);
173				break;
174			case MEDIA_BUS_FMT_RGB565_1X16:
175				dpi_c |= VC4_SET_FIELD(DPI_FORMAT_16BIT_565_RGB_1,
176						       DPI_FORMAT);
177				break;
178			default:
179				DRM_ERROR("Unknown media bus format %d\n",
180					  bus_format);
181				break;
182			}
183		}
184
185		if (connector->display_info.bus_flags & DRM_BUS_FLAG_PIXDATA_DRIVE_NEGEDGE)
186			dpi_c |= DPI_PIXEL_CLK_INVERT;
187
188		if (connector->display_info.bus_flags & DRM_BUS_FLAG_DE_LOW)
189			dpi_c |= DPI_OUTPUT_ENABLE_INVERT;
190	} else {
191		/* Default to 24bit if no connector found. */
192		dpi_c |= VC4_SET_FIELD(DPI_FORMAT_24BIT_888_RGB, DPI_FORMAT);
193	}
194
195	if (mode->flags & DRM_MODE_FLAG_NHSYNC)
196		dpi_c |= DPI_HSYNC_INVERT;
197	else if (!(mode->flags & DRM_MODE_FLAG_PHSYNC))
198		dpi_c |= DPI_HSYNC_DISABLE;
199
200	if (mode->flags & DRM_MODE_FLAG_NVSYNC)
201		dpi_c |= DPI_VSYNC_INVERT;
202	else if (!(mode->flags & DRM_MODE_FLAG_PVSYNC))
203		dpi_c |= DPI_VSYNC_DISABLE;
204
205	DPI_WRITE(DPI_C, dpi_c);
206
207	ret = clk_set_rate(dpi->pixel_clock, mode->clock * 1000);
208	if (ret)
209		DRM_ERROR("Failed to set clock rate: %d\n", ret);
210
211	ret = clk_prepare_enable(dpi->pixel_clock);
212	if (ret)
213		DRM_ERROR("Failed to set clock rate: %d\n", ret);
214}
215
216static enum drm_mode_status vc4_dpi_encoder_mode_valid(struct drm_encoder *encoder,
217						       const struct drm_display_mode *mode)
218{
219	if (mode->flags & DRM_MODE_FLAG_INTERLACE)
220		return MODE_NO_INTERLACE;
221
222	return MODE_OK;
223}
224
225static const struct drm_encoder_helper_funcs vc4_dpi_encoder_helper_funcs = {
226	.disable = vc4_dpi_encoder_disable,
227	.enable = vc4_dpi_encoder_enable,
228	.mode_valid = vc4_dpi_encoder_mode_valid,
229};
230
231static const struct of_device_id vc4_dpi_dt_match[] = {
232	{ .compatible = "brcm,bcm2835-dpi", .data = NULL },
233	{}
234};
235
236/* Sets up the next link in the display chain, whether it's a panel or
237 * a bridge.
238 */
239static int vc4_dpi_init_bridge(struct vc4_dpi *dpi)
240{
241	struct device *dev = &dpi->pdev->dev;
242	struct drm_panel *panel;
243	struct drm_bridge *bridge;
244	int ret;
245
246	ret = drm_of_find_panel_or_bridge(dev->of_node, 0, 0,
247					  &panel, &bridge);
248	if (ret) {
249		/* If nothing was connected in the DT, that's not an
250		 * error.
251		 */
252		if (ret == -ENODEV)
253			return 0;
254		else
255			return ret;
256	}
257
258	if (panel)
259		bridge = drm_panel_bridge_add_typed(panel,
260						    DRM_MODE_CONNECTOR_DPI);
261
262	return drm_bridge_attach(dpi->encoder, bridge, NULL, 0);
263}
264
265static int vc4_dpi_bind(struct device *dev, struct device *master, void *data)
266{
267	struct platform_device *pdev = to_platform_device(dev);
268	struct drm_device *drm = dev_get_drvdata(master);
269	struct vc4_dev *vc4 = to_vc4_dev(drm);
270	struct vc4_dpi *dpi;
271	struct vc4_dpi_encoder *vc4_dpi_encoder;
272	int ret;
273
274	dpi = devm_kzalloc(dev, sizeof(*dpi), GFP_KERNEL);
275	if (!dpi)
276		return -ENOMEM;
277
278	vc4_dpi_encoder = devm_kzalloc(dev, sizeof(*vc4_dpi_encoder),
279				       GFP_KERNEL);
280	if (!vc4_dpi_encoder)
281		return -ENOMEM;
282	vc4_dpi_encoder->base.type = VC4_ENCODER_TYPE_DPI;
283	vc4_dpi_encoder->dpi = dpi;
284	dpi->encoder = &vc4_dpi_encoder->base.base;
285
286	dpi->pdev = pdev;
287	dpi->regs = vc4_ioremap_regs(pdev, 0);
288	if (IS_ERR(dpi->regs))
289		return PTR_ERR(dpi->regs);
290	dpi->regset.base = dpi->regs;
291	dpi->regset.regs = dpi_regs;
292	dpi->regset.nregs = ARRAY_SIZE(dpi_regs);
293
294	if (DPI_READ(DPI_ID) != DPI_ID_VALUE) {
295		dev_err(dev, "Port returned 0x%08x for ID instead of 0x%08x\n",
296			DPI_READ(DPI_ID), DPI_ID_VALUE);
297		return -ENODEV;
298	}
299
300	dpi->core_clock = devm_clk_get(dev, "core");
301	if (IS_ERR(dpi->core_clock)) {
302		ret = PTR_ERR(dpi->core_clock);
303		if (ret != -EPROBE_DEFER)
304			DRM_ERROR("Failed to get core clock: %d\n", ret);
305		return ret;
306	}
307	dpi->pixel_clock = devm_clk_get(dev, "pixel");
308	if (IS_ERR(dpi->pixel_clock)) {
309		ret = PTR_ERR(dpi->pixel_clock);
310		if (ret != -EPROBE_DEFER)
311			DRM_ERROR("Failed to get pixel clock: %d\n", ret);
312		return ret;
313	}
314
315	ret = clk_prepare_enable(dpi->core_clock);
316	if (ret)
317		DRM_ERROR("Failed to turn on core clock: %d\n", ret);
318
319	drm_simple_encoder_init(drm, dpi->encoder, DRM_MODE_ENCODER_DPI);
320	drm_encoder_helper_add(dpi->encoder, &vc4_dpi_encoder_helper_funcs);
321
322	ret = vc4_dpi_init_bridge(dpi);
323	if (ret)
324		goto err_destroy_encoder;
325
326	dev_set_drvdata(dev, dpi);
327
328	vc4->dpi = dpi;
329
330	vc4_debugfs_add_regset32(drm, "dpi_regs", &dpi->regset);
331
332	return 0;
333
334err_destroy_encoder:
335	drm_encoder_cleanup(dpi->encoder);
336	clk_disable_unprepare(dpi->core_clock);
337	return ret;
338}
339
340static void vc4_dpi_unbind(struct device *dev, struct device *master,
341			   void *data)
342{
343	struct drm_device *drm = dev_get_drvdata(master);
344	struct vc4_dev *vc4 = to_vc4_dev(drm);
345	struct vc4_dpi *dpi = dev_get_drvdata(dev);
346
347	drm_of_panel_bridge_remove(dev->of_node, 0, 0);
348
349	drm_encoder_cleanup(dpi->encoder);
350
351	clk_disable_unprepare(dpi->core_clock);
352
353	vc4->dpi = NULL;
354}
355
356static const struct component_ops vc4_dpi_ops = {
357	.bind   = vc4_dpi_bind,
358	.unbind = vc4_dpi_unbind,
359};
360
361static int vc4_dpi_dev_probe(struct platform_device *pdev)
362{
363	return component_add(&pdev->dev, &vc4_dpi_ops);
364}
365
366static int vc4_dpi_dev_remove(struct platform_device *pdev)
367{
368	component_del(&pdev->dev, &vc4_dpi_ops);
369	return 0;
370}
371
372struct platform_driver vc4_dpi_driver = {
373	.probe = vc4_dpi_dev_probe,
374	.remove = vc4_dpi_dev_remove,
375	.driver = {
376		.name = "vc4_dpi",
377		.of_match_table = vc4_dpi_dt_match,
378	},
379};
380