1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) STMicroelectronics SA 2017
4  *
5  * Authors: Philippe Cornu <philippe.cornu@st.com>
6  *          Yannick Fertre <yannick.fertre@st.com>
7  */
8 
9 #include <linux/clk.h>
10 #include <linux/iopoll.h>
11 #include <linux/mod_devicetable.h>
12 #include <linux/module.h>
13 #include <linux/platform_device.h>
14 #include <linux/regulator/consumer.h>
15 
16 #include <video/mipi_display.h>
17 
18 #include <drm/bridge/dw_mipi_dsi.h>
19 #include <drm/drm_mipi_dsi.h>
20 #include <drm/drm_print.h>
21 
22 #define HWVER_130			0x31333000	/* IP version 1.30 */
23 #define HWVER_131			0x31333100	/* IP version 1.31 */
24 
25 /* DSI digital registers & bit definitions */
26 #define DSI_VERSION			0x00
27 #define VERSION				GENMASK(31, 8)
28 
29 /* DSI wrapper registers & bit definitions */
30 /* Note: registers are named as in the Reference Manual */
31 #define DSI_WCFGR	0x0400		/* Wrapper ConFiGuration Reg */
32 #define WCFGR_DSIM	BIT(0)		/* DSI Mode */
33 #define WCFGR_COLMUX	GENMASK(3, 1)	/* COLor MUltipleXing */
34 
35 #define DSI_WCR		0x0404		/* Wrapper Control Reg */
36 #define WCR_DSIEN	BIT(3)		/* DSI ENable */
37 
38 #define DSI_WISR	0x040C		/* Wrapper Interrupt and Status Reg */
39 #define WISR_PLLLS	BIT(8)		/* PLL Lock Status */
40 #define WISR_RRS	BIT(12)		/* Regulator Ready Status */
41 
42 #define DSI_WPCR0	0x0418		/* Wrapper Phy Conf Reg 0 */
43 #define WPCR0_UIX4	GENMASK(5, 0)	/* Unit Interval X 4 */
44 #define WPCR0_TDDL	BIT(16)		/* Turn Disable Data Lanes */
45 
46 #define DSI_WRPCR	0x0430		/* Wrapper Regulator & Pll Ctrl Reg */
47 #define WRPCR_PLLEN	BIT(0)		/* PLL ENable */
48 #define WRPCR_NDIV	GENMASK(8, 2)	/* pll loop DIVision Factor */
49 #define WRPCR_IDF	GENMASK(14, 11)	/* pll Input Division Factor */
50 #define WRPCR_ODF	GENMASK(17, 16)	/* pll Output Division Factor */
51 #define WRPCR_REGEN	BIT(24)		/* REGulator ENable */
52 #define WRPCR_BGREN	BIT(28)		/* BandGap Reference ENable */
53 #define IDF_MIN		1
54 #define IDF_MAX		7
55 #define NDIV_MIN	10
56 #define NDIV_MAX	125
57 #define ODF_MIN		1
58 #define ODF_MAX		8
59 
60 /* dsi color format coding according to the datasheet */
61 enum dsi_color {
62 	DSI_RGB565_CONF1,
63 	DSI_RGB565_CONF2,
64 	DSI_RGB565_CONF3,
65 	DSI_RGB666_CONF1,
66 	DSI_RGB666_CONF2,
67 	DSI_RGB888,
68 };
69 
70 #define LANE_MIN_KBPS	31250
71 #define LANE_MAX_KBPS	500000
72 
73 /* Sleep & timeout for regulator on/off, pll lock/unlock & fifo empty */
74 #define SLEEP_US	1000
75 #define TIMEOUT_US	200000
76 
77 struct dw_mipi_dsi_stm {
78 	void __iomem *base;
79 	struct clk *pllref_clk;
80 	struct dw_mipi_dsi *dsi;
81 	u32 hw_version;
82 	int lane_min_kbps;
83 	int lane_max_kbps;
84 	struct regulator *vdd_supply;
85 };
86 
87 static inline void dsi_write(struct dw_mipi_dsi_stm *dsi, u32 reg, u32 val)
88 {
89 	writel(val, dsi->base + reg);
90 }
91 
92 static inline u32 dsi_read(struct dw_mipi_dsi_stm *dsi, u32 reg)
93 {
94 	return readl(dsi->base + reg);
95 }
96 
97 static inline void dsi_set(struct dw_mipi_dsi_stm *dsi, u32 reg, u32 mask)
98 {
99 	dsi_write(dsi, reg, dsi_read(dsi, reg) | mask);
100 }
101 
102 static inline void dsi_clear(struct dw_mipi_dsi_stm *dsi, u32 reg, u32 mask)
103 {
104 	dsi_write(dsi, reg, dsi_read(dsi, reg) & ~mask);
105 }
106 
107 static inline void dsi_update_bits(struct dw_mipi_dsi_stm *dsi, u32 reg,
108 				   u32 mask, u32 val)
109 {
110 	dsi_write(dsi, reg, (dsi_read(dsi, reg) & ~mask) | val);
111 }
112 
113 static enum dsi_color dsi_color_from_mipi(enum mipi_dsi_pixel_format fmt)
114 {
115 	switch (fmt) {
116 	case MIPI_DSI_FMT_RGB888:
117 		return DSI_RGB888;
118 	case MIPI_DSI_FMT_RGB666:
119 		return DSI_RGB666_CONF2;
120 	case MIPI_DSI_FMT_RGB666_PACKED:
121 		return DSI_RGB666_CONF1;
122 	case MIPI_DSI_FMT_RGB565:
123 		return DSI_RGB565_CONF1;
124 	default:
125 		DRM_DEBUG_DRIVER("MIPI color invalid, so we use rgb888\n");
126 	}
127 	return DSI_RGB888;
128 }
129 
130 static int dsi_pll_get_clkout_khz(int clkin_khz, int idf, int ndiv, int odf)
131 {
132 	int divisor = idf * odf;
133 
134 	/* prevent from division by 0 */
135 	if (!divisor)
136 		return 0;
137 
138 	return DIV_ROUND_CLOSEST(clkin_khz * ndiv, divisor);
139 }
140 
141 static int dsi_pll_get_params(struct dw_mipi_dsi_stm *dsi,
142 			      int clkin_khz, int clkout_khz,
143 			      int *idf, int *ndiv, int *odf)
144 {
145 	int i, o, n, n_min, n_max;
146 	int fvco_min, fvco_max, delta, best_delta; /* all in khz */
147 
148 	/* Early checks preventing division by 0 & odd results */
149 	if (clkin_khz <= 0 || clkout_khz <= 0)
150 		return -EINVAL;
151 
152 	fvco_min = dsi->lane_min_kbps * 2 * ODF_MAX;
153 	fvco_max = dsi->lane_max_kbps * 2 * ODF_MIN;
154 
155 	best_delta = 1000000; /* big started value (1000000khz) */
156 
157 	for (i = IDF_MIN; i <= IDF_MAX; i++) {
158 		/* Compute ndiv range according to Fvco */
159 		n_min = ((fvco_min * i) / (2 * clkin_khz)) + 1;
160 		n_max = (fvco_max * i) / (2 * clkin_khz);
161 
162 		/* No need to continue idf loop if we reach ndiv max */
163 		if (n_min >= NDIV_MAX)
164 			break;
165 
166 		/* Clamp ndiv to valid values */
167 		if (n_min < NDIV_MIN)
168 			n_min = NDIV_MIN;
169 		if (n_max > NDIV_MAX)
170 			n_max = NDIV_MAX;
171 
172 		for (o = ODF_MIN; o <= ODF_MAX; o *= 2) {
173 			n = DIV_ROUND_CLOSEST(i * o * clkout_khz, clkin_khz);
174 			/* Check ndiv according to vco range */
175 			if (n < n_min || n > n_max)
176 				continue;
177 			/* Check if new delta is better & saves parameters */
178 			delta = dsi_pll_get_clkout_khz(clkin_khz, i, n, o) -
179 				clkout_khz;
180 			if (delta < 0)
181 				delta = -delta;
182 			if (delta < best_delta) {
183 				*idf = i;
184 				*ndiv = n;
185 				*odf = o;
186 				best_delta = delta;
187 			}
188 			/* fast return in case of "perfect result" */
189 			if (!delta)
190 				return 0;
191 		}
192 	}
193 
194 	return 0;
195 }
196 
197 static int dw_mipi_dsi_phy_init(void *priv_data)
198 {
199 	struct dw_mipi_dsi_stm *dsi = priv_data;
200 	u32 val;
201 	int ret;
202 
203 	/* Enable the regulator */
204 	dsi_set(dsi, DSI_WRPCR, WRPCR_REGEN | WRPCR_BGREN);
205 	ret = readl_poll_timeout(dsi->base + DSI_WISR, val, val & WISR_RRS,
206 				 SLEEP_US, TIMEOUT_US);
207 	if (ret)
208 		DRM_DEBUG_DRIVER("!TIMEOUT! waiting REGU, let's continue\n");
209 
210 	/* Enable the DSI PLL & wait for its lock */
211 	dsi_set(dsi, DSI_WRPCR, WRPCR_PLLEN);
212 	ret = readl_poll_timeout(dsi->base + DSI_WISR, val, val & WISR_PLLLS,
213 				 SLEEP_US, TIMEOUT_US);
214 	if (ret)
215 		DRM_DEBUG_DRIVER("!TIMEOUT! waiting PLL, let's continue\n");
216 
217 	return 0;
218 }
219 
220 static void dw_mipi_dsi_phy_power_on(void *priv_data)
221 {
222 	struct dw_mipi_dsi_stm *dsi = priv_data;
223 
224 	DRM_DEBUG_DRIVER("\n");
225 
226 	/* Enable the DSI wrapper */
227 	dsi_set(dsi, DSI_WCR, WCR_DSIEN);
228 }
229 
230 static void dw_mipi_dsi_phy_power_off(void *priv_data)
231 {
232 	struct dw_mipi_dsi_stm *dsi = priv_data;
233 
234 	DRM_DEBUG_DRIVER("\n");
235 
236 	/* Disable the DSI wrapper */
237 	dsi_clear(dsi, DSI_WCR, WCR_DSIEN);
238 }
239 
240 static int
241 dw_mipi_dsi_get_lane_mbps(void *priv_data, const struct drm_display_mode *mode,
242 			  unsigned long mode_flags, u32 lanes, u32 format,
243 			  unsigned int *lane_mbps)
244 {
245 	struct dw_mipi_dsi_stm *dsi = priv_data;
246 	unsigned int idf, ndiv, odf, pll_in_khz, pll_out_khz;
247 	int ret, bpp;
248 	u32 val;
249 
250 	/* Update lane capabilities according to hw version */
251 	dsi->lane_min_kbps = LANE_MIN_KBPS;
252 	dsi->lane_max_kbps = LANE_MAX_KBPS;
253 	if (dsi->hw_version == HWVER_131) {
254 		dsi->lane_min_kbps *= 2;
255 		dsi->lane_max_kbps *= 2;
256 	}
257 
258 	pll_in_khz = (unsigned int)(clk_get_rate(dsi->pllref_clk) / 1000);
259 
260 	/* Compute requested pll out */
261 	bpp = mipi_dsi_pixel_format_to_bpp(format);
262 	pll_out_khz = mode->clock * bpp / lanes;
263 	/* Add 20% to pll out to be higher than pixel bw (burst mode only) */
264 	pll_out_khz = (pll_out_khz * 12) / 10;
265 	if (pll_out_khz > dsi->lane_max_kbps) {
266 		pll_out_khz = dsi->lane_max_kbps;
267 		DRM_WARN("Warning max phy mbps is used\n");
268 	}
269 	if (pll_out_khz < dsi->lane_min_kbps) {
270 		pll_out_khz = dsi->lane_min_kbps;
271 		DRM_WARN("Warning min phy mbps is used\n");
272 	}
273 
274 	/* Compute best pll parameters */
275 	idf = 0;
276 	ndiv = 0;
277 	odf = 0;
278 	ret = dsi_pll_get_params(dsi, pll_in_khz, pll_out_khz,
279 				 &idf, &ndiv, &odf);
280 	if (ret)
281 		DRM_WARN("Warning dsi_pll_get_params(): bad params\n");
282 
283 	/* Get the adjusted pll out value */
284 	pll_out_khz = dsi_pll_get_clkout_khz(pll_in_khz, idf, ndiv, odf);
285 
286 	/* Set the PLL division factors */
287 	dsi_update_bits(dsi, DSI_WRPCR,	WRPCR_NDIV | WRPCR_IDF | WRPCR_ODF,
288 			(ndiv << 2) | (idf << 11) | ((ffs(odf) - 1) << 16));
289 
290 	/* Compute uix4 & set the bit period in high-speed mode */
291 	val = 4000000 / pll_out_khz;
292 	dsi_update_bits(dsi, DSI_WPCR0, WPCR0_UIX4, val);
293 
294 	/* Select video mode by resetting DSIM bit */
295 	dsi_clear(dsi, DSI_WCFGR, WCFGR_DSIM);
296 
297 	/* Select the color coding */
298 	dsi_update_bits(dsi, DSI_WCFGR, WCFGR_COLMUX,
299 			dsi_color_from_mipi(format) << 1);
300 
301 	*lane_mbps = pll_out_khz / 1000;
302 
303 	DRM_DEBUG_DRIVER("pll_in %ukHz pll_out %ukHz lane_mbps %uMHz\n",
304 			 pll_in_khz, pll_out_khz, *lane_mbps);
305 
306 	return 0;
307 }
308 
309 static const struct dw_mipi_dsi_phy_ops dw_mipi_dsi_stm_phy_ops = {
310 	.init = dw_mipi_dsi_phy_init,
311 	.power_on = dw_mipi_dsi_phy_power_on,
312 	.power_off = dw_mipi_dsi_phy_power_off,
313 	.get_lane_mbps = dw_mipi_dsi_get_lane_mbps,
314 };
315 
316 static struct dw_mipi_dsi_plat_data dw_mipi_dsi_stm_plat_data = {
317 	.max_data_lanes = 2,
318 	.phy_ops = &dw_mipi_dsi_stm_phy_ops,
319 };
320 
321 static const struct of_device_id dw_mipi_dsi_stm_dt_ids[] = {
322 	{ .compatible = "st,stm32-dsi", .data = &dw_mipi_dsi_stm_plat_data, },
323 	{ },
324 };
325 MODULE_DEVICE_TABLE(of, dw_mipi_dsi_stm_dt_ids);
326 
327 static int dw_mipi_dsi_stm_probe(struct platform_device *pdev)
328 {
329 	struct device *dev = &pdev->dev;
330 	struct dw_mipi_dsi_stm *dsi;
331 	struct clk *pclk;
332 	struct resource *res;
333 	int ret;
334 
335 	dsi = devm_kzalloc(dev, sizeof(*dsi), GFP_KERNEL);
336 	if (!dsi)
337 		return -ENOMEM;
338 
339 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
340 	dsi->base = devm_ioremap_resource(dev, res);
341 	if (IS_ERR(dsi->base)) {
342 		ret = PTR_ERR(dsi->base);
343 		DRM_ERROR("Unable to get dsi registers %d\n", ret);
344 		return ret;
345 	}
346 
347 	dsi->vdd_supply = devm_regulator_get(dev, "phy-dsi");
348 	if (IS_ERR(dsi->vdd_supply)) {
349 		ret = PTR_ERR(dsi->vdd_supply);
350 		if (ret != -EPROBE_DEFER)
351 			DRM_ERROR("Failed to request regulator: %d\n", ret);
352 		return ret;
353 	}
354 
355 	ret = regulator_enable(dsi->vdd_supply);
356 	if (ret) {
357 		DRM_ERROR("Failed to enable regulator: %d\n", ret);
358 		return ret;
359 	}
360 
361 	dsi->pllref_clk = devm_clk_get(dev, "ref");
362 	if (IS_ERR(dsi->pllref_clk)) {
363 		ret = PTR_ERR(dsi->pllref_clk);
364 		DRM_ERROR("Unable to get pll reference clock: %d\n", ret);
365 		goto err_clk_get;
366 	}
367 
368 	ret = clk_prepare_enable(dsi->pllref_clk);
369 	if (ret) {
370 		DRM_ERROR("Failed to enable pllref_clk: %d\n", ret);
371 		goto err_clk_get;
372 	}
373 
374 	pclk = devm_clk_get(dev, "pclk");
375 	if (IS_ERR(pclk)) {
376 		ret = PTR_ERR(pclk);
377 		DRM_ERROR("Unable to get peripheral clock: %d\n", ret);
378 		goto err_dsi_probe;
379 	}
380 
381 	ret = clk_prepare_enable(pclk);
382 	if (ret) {
383 		DRM_ERROR("%s: Failed to enable peripheral clk\n", __func__);
384 		goto err_dsi_probe;
385 	}
386 
387 	dsi->hw_version = dsi_read(dsi, DSI_VERSION) & VERSION;
388 	clk_disable_unprepare(pclk);
389 
390 	if (dsi->hw_version != HWVER_130 && dsi->hw_version != HWVER_131) {
391 		ret = -ENODEV;
392 		DRM_ERROR("bad dsi hardware version\n");
393 		goto err_dsi_probe;
394 	}
395 
396 	dw_mipi_dsi_stm_plat_data.base = dsi->base;
397 	dw_mipi_dsi_stm_plat_data.priv_data = dsi;
398 
399 	platform_set_drvdata(pdev, dsi);
400 
401 	dsi->dsi = dw_mipi_dsi_probe(pdev, &dw_mipi_dsi_stm_plat_data);
402 	if (IS_ERR(dsi->dsi)) {
403 		ret = PTR_ERR(dsi->dsi);
404 		DRM_ERROR("Failed to initialize mipi dsi host: %d\n", ret);
405 		goto err_dsi_probe;
406 	}
407 
408 	return 0;
409 
410 err_dsi_probe:
411 	clk_disable_unprepare(dsi->pllref_clk);
412 err_clk_get:
413 	regulator_disable(dsi->vdd_supply);
414 
415 	return ret;
416 }
417 
418 static int dw_mipi_dsi_stm_remove(struct platform_device *pdev)
419 {
420 	struct dw_mipi_dsi_stm *dsi = platform_get_drvdata(pdev);
421 
422 	dw_mipi_dsi_remove(dsi->dsi);
423 	clk_disable_unprepare(dsi->pllref_clk);
424 	regulator_disable(dsi->vdd_supply);
425 
426 	return 0;
427 }
428 
429 static int __maybe_unused dw_mipi_dsi_stm_suspend(struct device *dev)
430 {
431 	struct dw_mipi_dsi_stm *dsi = dw_mipi_dsi_stm_plat_data.priv_data;
432 
433 	DRM_DEBUG_DRIVER("\n");
434 
435 	clk_disable_unprepare(dsi->pllref_clk);
436 	regulator_disable(dsi->vdd_supply);
437 
438 	return 0;
439 }
440 
441 static int __maybe_unused dw_mipi_dsi_stm_resume(struct device *dev)
442 {
443 	struct dw_mipi_dsi_stm *dsi = dw_mipi_dsi_stm_plat_data.priv_data;
444 	int ret;
445 
446 	DRM_DEBUG_DRIVER("\n");
447 
448 	ret = regulator_enable(dsi->vdd_supply);
449 	if (ret) {
450 		DRM_ERROR("Failed to enable regulator: %d\n", ret);
451 		return ret;
452 	}
453 
454 	ret = clk_prepare_enable(dsi->pllref_clk);
455 	if (ret) {
456 		regulator_disable(dsi->vdd_supply);
457 		DRM_ERROR("Failed to enable pllref_clk: %d\n", ret);
458 		return ret;
459 	}
460 
461 	return 0;
462 }
463 
464 static const struct dev_pm_ops dw_mipi_dsi_stm_pm_ops = {
465 	SET_SYSTEM_SLEEP_PM_OPS(dw_mipi_dsi_stm_suspend,
466 				dw_mipi_dsi_stm_resume)
467 };
468 
469 static struct platform_driver dw_mipi_dsi_stm_driver = {
470 	.probe		= dw_mipi_dsi_stm_probe,
471 	.remove		= dw_mipi_dsi_stm_remove,
472 	.driver		= {
473 		.of_match_table = dw_mipi_dsi_stm_dt_ids,
474 		.name	= "stm32-display-dsi",
475 		.pm = &dw_mipi_dsi_stm_pm_ops,
476 	},
477 };
478 
479 module_platform_driver(dw_mipi_dsi_stm_driver);
480 
481 MODULE_AUTHOR("Philippe Cornu <philippe.cornu@st.com>");
482 MODULE_AUTHOR("Yannick Fertre <yannick.fertre@st.com>");
483 MODULE_DESCRIPTION("STMicroelectronics DW MIPI DSI host controller driver");
484 MODULE_LICENSE("GPL v2");
485