xref: /openbmc/linux/drivers/gpu/drm/bridge/fsl-ldb.c (revision cb051977)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (C) 2022 Marek Vasut <marex@denx.de>
4  */
5 
6 #include <linux/clk.h>
7 #include <linux/media-bus-format.h>
8 #include <linux/mfd/syscon.h>
9 #include <linux/module.h>
10 #include <linux/of.h>
11 #include <linux/of_graph.h>
12 #include <linux/platform_device.h>
13 #include <linux/regmap.h>
14 
15 #include <drm/drm_atomic_helper.h>
16 #include <drm/drm_bridge.h>
17 #include <drm/drm_of.h>
18 #include <drm/drm_panel.h>
19 
20 #define LDB_CTRL_CH0_ENABLE			BIT(0)
21 #define LDB_CTRL_CH0_DI_SELECT			BIT(1)
22 #define LDB_CTRL_CH1_ENABLE			BIT(2)
23 #define LDB_CTRL_CH1_DI_SELECT			BIT(3)
24 #define LDB_CTRL_SPLIT_MODE			BIT(4)
25 #define LDB_CTRL_CH0_DATA_WIDTH			BIT(5)
26 #define LDB_CTRL_CH0_BIT_MAPPING		BIT(6)
27 #define LDB_CTRL_CH1_DATA_WIDTH			BIT(7)
28 #define LDB_CTRL_CH1_BIT_MAPPING		BIT(8)
29 #define LDB_CTRL_DI0_VSYNC_POLARITY		BIT(9)
30 #define LDB_CTRL_DI1_VSYNC_POLARITY		BIT(10)
31 #define LDB_CTRL_REG_CH0_FIFO_RESET		BIT(11)
32 #define LDB_CTRL_REG_CH1_FIFO_RESET		BIT(12)
33 #define LDB_CTRL_ASYNC_FIFO_ENABLE		BIT(24)
34 #define LDB_CTRL_ASYNC_FIFO_THRESHOLD_MASK	GENMASK(27, 25)
35 
36 #define LVDS_CTRL_CH0_EN			BIT(0)
37 #define LVDS_CTRL_CH1_EN			BIT(1)
38 /*
39  * LVDS_CTRL_LVDS_EN bit is poorly named in i.MX93 reference manual.
40  * Clear it to enable LVDS and set it to disable LVDS.
41  */
42 #define LVDS_CTRL_LVDS_EN			BIT(1)
43 #define LVDS_CTRL_VBG_EN			BIT(2)
44 #define LVDS_CTRL_HS_EN				BIT(3)
45 #define LVDS_CTRL_PRE_EMPH_EN			BIT(4)
46 #define LVDS_CTRL_PRE_EMPH_ADJ(n)		(((n) & 0x7) << 5)
47 #define LVDS_CTRL_PRE_EMPH_ADJ_MASK		GENMASK(7, 5)
48 #define LVDS_CTRL_CM_ADJ(n)			(((n) & 0x7) << 8)
49 #define LVDS_CTRL_CM_ADJ_MASK			GENMASK(10, 8)
50 #define LVDS_CTRL_CC_ADJ(n)			(((n) & 0x7) << 11)
51 #define LVDS_CTRL_CC_ADJ_MASK			GENMASK(13, 11)
52 #define LVDS_CTRL_SLEW_ADJ(n)			(((n) & 0x7) << 14)
53 #define LVDS_CTRL_SLEW_ADJ_MASK			GENMASK(16, 14)
54 #define LVDS_CTRL_VBG_ADJ(n)			(((n) & 0x7) << 17)
55 #define LVDS_CTRL_VBG_ADJ_MASK			GENMASK(19, 17)
56 
57 enum fsl_ldb_devtype {
58 	IMX6SX_LDB,
59 	IMX8MP_LDB,
60 	IMX93_LDB,
61 };
62 
63 struct fsl_ldb_devdata {
64 	u32 ldb_ctrl;
65 	u32 lvds_ctrl;
66 	bool lvds_en_bit;
67 	bool single_ctrl_reg;
68 };
69 
70 static const struct fsl_ldb_devdata fsl_ldb_devdata[] = {
71 	[IMX6SX_LDB] = {
72 		.ldb_ctrl = 0x18,
73 		.single_ctrl_reg = true,
74 	},
75 	[IMX8MP_LDB] = {
76 		.ldb_ctrl = 0x5c,
77 		.lvds_ctrl = 0x128,
78 	},
79 	[IMX93_LDB] = {
80 		.ldb_ctrl = 0x20,
81 		.lvds_ctrl = 0x24,
82 		.lvds_en_bit = true,
83 	},
84 };
85 
86 struct fsl_ldb {
87 	struct device *dev;
88 	struct drm_bridge bridge;
89 	struct drm_bridge *panel_bridge;
90 	struct clk *clk;
91 	struct regmap *regmap;
92 	const struct fsl_ldb_devdata *devdata;
93 	bool ch0_enabled;
94 	bool ch1_enabled;
95 };
96 
97 static bool fsl_ldb_is_dual(const struct fsl_ldb *fsl_ldb)
98 {
99 	return (fsl_ldb->ch0_enabled && fsl_ldb->ch1_enabled);
100 }
101 
102 static inline struct fsl_ldb *to_fsl_ldb(struct drm_bridge *bridge)
103 {
104 	return container_of(bridge, struct fsl_ldb, bridge);
105 }
106 
107 static unsigned long fsl_ldb_link_frequency(struct fsl_ldb *fsl_ldb, int clock)
108 {
109 	if (fsl_ldb_is_dual(fsl_ldb))
110 		return clock * 3500;
111 	else
112 		return clock * 7000;
113 }
114 
115 static int fsl_ldb_attach(struct drm_bridge *bridge,
116 			  enum drm_bridge_attach_flags flags)
117 {
118 	struct fsl_ldb *fsl_ldb = to_fsl_ldb(bridge);
119 
120 	return drm_bridge_attach(bridge->encoder, fsl_ldb->panel_bridge,
121 				 bridge, flags);
122 }
123 
124 static void fsl_ldb_atomic_enable(struct drm_bridge *bridge,
125 				  struct drm_bridge_state *old_bridge_state)
126 {
127 	struct fsl_ldb *fsl_ldb = to_fsl_ldb(bridge);
128 	struct drm_atomic_state *state = old_bridge_state->base.state;
129 	const struct drm_bridge_state *bridge_state;
130 	const struct drm_crtc_state *crtc_state;
131 	const struct drm_display_mode *mode;
132 	struct drm_connector *connector;
133 	struct drm_crtc *crtc;
134 	unsigned long configured_link_freq;
135 	unsigned long requested_link_freq;
136 	bool lvds_format_24bpp;
137 	bool lvds_format_jeida;
138 	u32 reg;
139 
140 	/* Get the LVDS format from the bridge state. */
141 	bridge_state = drm_atomic_get_new_bridge_state(state, bridge);
142 
143 	switch (bridge_state->output_bus_cfg.format) {
144 	case MEDIA_BUS_FMT_RGB666_1X7X3_SPWG:
145 		lvds_format_24bpp = false;
146 		lvds_format_jeida = true;
147 		break;
148 	case MEDIA_BUS_FMT_RGB888_1X7X4_JEIDA:
149 		lvds_format_24bpp = true;
150 		lvds_format_jeida = true;
151 		break;
152 	case MEDIA_BUS_FMT_RGB888_1X7X4_SPWG:
153 		lvds_format_24bpp = true;
154 		lvds_format_jeida = false;
155 		break;
156 	default:
157 		/*
158 		 * Some bridges still don't set the correct LVDS bus pixel
159 		 * format, use SPWG24 default format until those are fixed.
160 		 */
161 		lvds_format_24bpp = true;
162 		lvds_format_jeida = false;
163 		dev_warn(fsl_ldb->dev,
164 			 "Unsupported LVDS bus format 0x%04x, please check output bridge driver. Falling back to SPWG24.\n",
165 			 bridge_state->output_bus_cfg.format);
166 		break;
167 	}
168 
169 	/*
170 	 * Retrieve the CRTC adjusted mode. This requires a little dance to go
171 	 * from the bridge to the encoder, to the connector and to the CRTC.
172 	 */
173 	connector = drm_atomic_get_new_connector_for_encoder(state,
174 							     bridge->encoder);
175 	crtc = drm_atomic_get_new_connector_state(state, connector)->crtc;
176 	crtc_state = drm_atomic_get_new_crtc_state(state, crtc);
177 	mode = &crtc_state->adjusted_mode;
178 
179 	requested_link_freq = fsl_ldb_link_frequency(fsl_ldb, mode->clock);
180 	clk_set_rate(fsl_ldb->clk, requested_link_freq);
181 
182 	configured_link_freq = clk_get_rate(fsl_ldb->clk);
183 	if (configured_link_freq != requested_link_freq)
184 		dev_warn(fsl_ldb->dev, "Configured LDB clock (%lu Hz) does not match requested LVDS clock: %lu Hz\n",
185 			 configured_link_freq,
186 			 requested_link_freq);
187 
188 	clk_prepare_enable(fsl_ldb->clk);
189 
190 	/* Program LDB_CTRL */
191 	reg =	(fsl_ldb->ch0_enabled ? LDB_CTRL_CH0_ENABLE : 0) |
192 		(fsl_ldb->ch1_enabled ? LDB_CTRL_CH1_ENABLE : 0) |
193 		(fsl_ldb_is_dual(fsl_ldb) ? LDB_CTRL_SPLIT_MODE : 0);
194 
195 	if (lvds_format_24bpp)
196 		reg |=	(fsl_ldb->ch0_enabled ? LDB_CTRL_CH0_DATA_WIDTH : 0) |
197 			(fsl_ldb->ch1_enabled ? LDB_CTRL_CH1_DATA_WIDTH : 0);
198 
199 	if (lvds_format_jeida)
200 		reg |=	(fsl_ldb->ch0_enabled ? LDB_CTRL_CH0_BIT_MAPPING : 0) |
201 			(fsl_ldb->ch1_enabled ? LDB_CTRL_CH1_BIT_MAPPING : 0);
202 
203 	if (mode->flags & DRM_MODE_FLAG_PVSYNC)
204 		reg |=	(fsl_ldb->ch0_enabled ? LDB_CTRL_DI0_VSYNC_POLARITY : 0) |
205 			(fsl_ldb->ch1_enabled ? LDB_CTRL_DI1_VSYNC_POLARITY : 0);
206 
207 	regmap_write(fsl_ldb->regmap, fsl_ldb->devdata->ldb_ctrl, reg);
208 
209 	if (fsl_ldb->devdata->single_ctrl_reg)
210 		return;
211 
212 	/* Program LVDS_CTRL */
213 	reg = LVDS_CTRL_CC_ADJ(2) | LVDS_CTRL_PRE_EMPH_EN |
214 	      LVDS_CTRL_PRE_EMPH_ADJ(3) | LVDS_CTRL_VBG_EN;
215 	regmap_write(fsl_ldb->regmap, fsl_ldb->devdata->lvds_ctrl, reg);
216 
217 	/* Wait for VBG to stabilize. */
218 	usleep_range(15, 20);
219 
220 	reg |=	(fsl_ldb->ch0_enabled ? LVDS_CTRL_CH0_EN : 0) |
221 		(fsl_ldb->ch1_enabled ? LVDS_CTRL_CH1_EN : 0);
222 
223 	regmap_write(fsl_ldb->regmap, fsl_ldb->devdata->lvds_ctrl, reg);
224 }
225 
226 static void fsl_ldb_atomic_disable(struct drm_bridge *bridge,
227 				   struct drm_bridge_state *old_bridge_state)
228 {
229 	struct fsl_ldb *fsl_ldb = to_fsl_ldb(bridge);
230 
231 	/* Stop channel(s). */
232 	if (fsl_ldb->devdata->lvds_en_bit)
233 		/* Set LVDS_CTRL_LVDS_EN bit to disable. */
234 		regmap_write(fsl_ldb->regmap, fsl_ldb->devdata->lvds_ctrl,
235 			     LVDS_CTRL_LVDS_EN);
236 	else
237 		if (!fsl_ldb->devdata->single_ctrl_reg)
238 			regmap_write(fsl_ldb->regmap, fsl_ldb->devdata->lvds_ctrl, 0);
239 	regmap_write(fsl_ldb->regmap, fsl_ldb->devdata->ldb_ctrl, 0);
240 
241 	clk_disable_unprepare(fsl_ldb->clk);
242 }
243 
244 #define MAX_INPUT_SEL_FORMATS 1
245 static u32 *
246 fsl_ldb_atomic_get_input_bus_fmts(struct drm_bridge *bridge,
247 				  struct drm_bridge_state *bridge_state,
248 				  struct drm_crtc_state *crtc_state,
249 				  struct drm_connector_state *conn_state,
250 				  u32 output_fmt,
251 				  unsigned int *num_input_fmts)
252 {
253 	u32 *input_fmts;
254 
255 	*num_input_fmts = 0;
256 
257 	input_fmts = kcalloc(MAX_INPUT_SEL_FORMATS, sizeof(*input_fmts),
258 			     GFP_KERNEL);
259 	if (!input_fmts)
260 		return NULL;
261 
262 	input_fmts[0] = MEDIA_BUS_FMT_RGB888_1X24;
263 	*num_input_fmts = MAX_INPUT_SEL_FORMATS;
264 
265 	return input_fmts;
266 }
267 
268 static enum drm_mode_status
269 fsl_ldb_mode_valid(struct drm_bridge *bridge,
270 		   const struct drm_display_info *info,
271 		   const struct drm_display_mode *mode)
272 {
273 	struct fsl_ldb *fsl_ldb = to_fsl_ldb(bridge);
274 
275 	if (mode->clock > (fsl_ldb_is_dual(fsl_ldb) ? 160000 : 80000))
276 		return MODE_CLOCK_HIGH;
277 
278 	return MODE_OK;
279 }
280 
281 static const struct drm_bridge_funcs funcs = {
282 	.attach = fsl_ldb_attach,
283 	.atomic_enable = fsl_ldb_atomic_enable,
284 	.atomic_disable = fsl_ldb_atomic_disable,
285 	.atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
286 	.atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
287 	.atomic_get_input_bus_fmts = fsl_ldb_atomic_get_input_bus_fmts,
288 	.atomic_reset = drm_atomic_helper_bridge_reset,
289 	.mode_valid = fsl_ldb_mode_valid,
290 };
291 
292 static int fsl_ldb_probe(struct platform_device *pdev)
293 {
294 	struct device *dev = &pdev->dev;
295 	struct device_node *panel_node;
296 	struct device_node *remote1, *remote2;
297 	struct drm_panel *panel;
298 	struct fsl_ldb *fsl_ldb;
299 	int dual_link;
300 
301 	fsl_ldb = devm_kzalloc(dev, sizeof(*fsl_ldb), GFP_KERNEL);
302 	if (!fsl_ldb)
303 		return -ENOMEM;
304 
305 	fsl_ldb->devdata = of_device_get_match_data(dev);
306 	if (!fsl_ldb->devdata)
307 		return -EINVAL;
308 
309 	fsl_ldb->dev = &pdev->dev;
310 	fsl_ldb->bridge.funcs = &funcs;
311 	fsl_ldb->bridge.of_node = dev->of_node;
312 
313 	fsl_ldb->clk = devm_clk_get(dev, "ldb");
314 	if (IS_ERR(fsl_ldb->clk))
315 		return PTR_ERR(fsl_ldb->clk);
316 
317 	fsl_ldb->regmap = syscon_node_to_regmap(dev->of_node->parent);
318 	if (IS_ERR(fsl_ldb->regmap))
319 		return PTR_ERR(fsl_ldb->regmap);
320 
321 	/* Locate the remote ports and the panel node */
322 	remote1 = of_graph_get_remote_node(dev->of_node, 1, 0);
323 	remote2 = of_graph_get_remote_node(dev->of_node, 2, 0);
324 	fsl_ldb->ch0_enabled = (remote1 != NULL);
325 	fsl_ldb->ch1_enabled = (remote2 != NULL);
326 	panel_node = of_node_get(remote1 ? remote1 : remote2);
327 	of_node_put(remote1);
328 	of_node_put(remote2);
329 
330 	if (!fsl_ldb->ch0_enabled && !fsl_ldb->ch1_enabled) {
331 		of_node_put(panel_node);
332 		return dev_err_probe(dev, -ENXIO, "No panel node found");
333 	}
334 
335 	dev_dbg(dev, "Using %s\n",
336 		fsl_ldb_is_dual(fsl_ldb) ? "dual-link mode" :
337 		fsl_ldb->ch0_enabled ? "channel 0" : "channel 1");
338 
339 	panel = of_drm_find_panel(panel_node);
340 	of_node_put(panel_node);
341 	if (IS_ERR(panel))
342 		return PTR_ERR(panel);
343 
344 	fsl_ldb->panel_bridge = devm_drm_panel_bridge_add(dev, panel);
345 	if (IS_ERR(fsl_ldb->panel_bridge))
346 		return PTR_ERR(fsl_ldb->panel_bridge);
347 
348 
349 	if (fsl_ldb_is_dual(fsl_ldb)) {
350 		struct device_node *port1, *port2;
351 
352 		port1 = of_graph_get_port_by_id(dev->of_node, 1);
353 		port2 = of_graph_get_port_by_id(dev->of_node, 2);
354 		dual_link = drm_of_lvds_get_dual_link_pixel_order(port1, port2);
355 		of_node_put(port1);
356 		of_node_put(port2);
357 
358 		if (dual_link < 0)
359 			return dev_err_probe(dev, dual_link,
360 					     "Error getting dual link configuration\n");
361 
362 		/* Only DRM_LVDS_DUAL_LINK_ODD_EVEN_PIXELS is supported */
363 		if (dual_link == DRM_LVDS_DUAL_LINK_EVEN_ODD_PIXELS) {
364 			dev_err(dev, "LVDS channel pixel swap not supported.\n");
365 			return -EINVAL;
366 		}
367 	}
368 
369 	platform_set_drvdata(pdev, fsl_ldb);
370 
371 	drm_bridge_add(&fsl_ldb->bridge);
372 
373 	return 0;
374 }
375 
376 static void fsl_ldb_remove(struct platform_device *pdev)
377 {
378 	struct fsl_ldb *fsl_ldb = platform_get_drvdata(pdev);
379 
380 	drm_bridge_remove(&fsl_ldb->bridge);
381 }
382 
383 static const struct of_device_id fsl_ldb_match[] = {
384 	{ .compatible = "fsl,imx6sx-ldb",
385 	  .data = &fsl_ldb_devdata[IMX6SX_LDB], },
386 	{ .compatible = "fsl,imx8mp-ldb",
387 	  .data = &fsl_ldb_devdata[IMX8MP_LDB], },
388 	{ .compatible = "fsl,imx93-ldb",
389 	  .data = &fsl_ldb_devdata[IMX93_LDB], },
390 	{ /* sentinel */ },
391 };
392 MODULE_DEVICE_TABLE(of, fsl_ldb_match);
393 
394 static struct platform_driver fsl_ldb_driver = {
395 	.probe	= fsl_ldb_probe,
396 	.remove_new = fsl_ldb_remove,
397 	.driver		= {
398 		.name		= "fsl-ldb",
399 		.of_match_table	= fsl_ldb_match,
400 	},
401 };
402 module_platform_driver(fsl_ldb_driver);
403 
404 MODULE_AUTHOR("Marek Vasut <marex@denx.de>");
405 MODULE_DESCRIPTION("Freescale i.MX8MP LDB");
406 MODULE_LICENSE("GPL");
407