1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * This file is part the core part STM32 DFSDM driver
4  *
5  * Copyright (C) 2017, STMicroelectronics - All Rights Reserved
6  * Author(s): Arnaud Pouliquen <arnaud.pouliquen@st.com> for STMicroelectronics.
7  */
8 
9 #include <linux/bitfield.h>
10 #include <linux/clk.h>
11 #include <linux/iio/iio.h>
12 #include <linux/iio/sysfs.h>
13 #include <linux/interrupt.h>
14 #include <linux/module.h>
15 #include <linux/of.h>
16 #include <linux/of_platform.h>
17 #include <linux/pinctrl/consumer.h>
18 #include <linux/platform_device.h>
19 #include <linux/pm_runtime.h>
20 #include <linux/regmap.h>
21 #include <linux/slab.h>
22 
23 #include "stm32-dfsdm.h"
24 
25 /**
26  * struct stm32_dfsdm_dev_data - DFSDM compatible configuration data
27  * @ipid: DFSDM identification number. Used only if hardware provides identification registers
28  * @num_filters: DFSDM number of filters. Unused if identification registers are available
29  * @num_channels: DFSDM number of channels. Unused if identification registers are available
30  * @regmap_cfg: SAI register map configuration pointer
31  */
32 struct stm32_dfsdm_dev_data {
33 	u32 ipid;
34 	unsigned int num_filters;
35 	unsigned int num_channels;
36 	const struct regmap_config *regmap_cfg;
37 };
38 
39 #define STM32H7_DFSDM_NUM_FILTERS	4
40 #define STM32H7_DFSDM_NUM_CHANNELS	8
41 
42 static bool stm32_dfsdm_volatile_reg(struct device *dev, unsigned int reg)
43 {
44 	if (reg < DFSDM_FILTER_BASE_ADR)
45 		return false;
46 
47 	/*
48 	 * Mask is done on register to avoid to list registers of all
49 	 * filter instances.
50 	 */
51 	switch (reg & DFSDM_FILTER_REG_MASK) {
52 	case DFSDM_CR1(0) & DFSDM_FILTER_REG_MASK:
53 	case DFSDM_ISR(0) & DFSDM_FILTER_REG_MASK:
54 	case DFSDM_JDATAR(0) & DFSDM_FILTER_REG_MASK:
55 	case DFSDM_RDATAR(0) & DFSDM_FILTER_REG_MASK:
56 		return true;
57 	}
58 
59 	return false;
60 }
61 
62 static const struct regmap_config stm32h7_dfsdm_regmap_cfg = {
63 	.reg_bits = 32,
64 	.val_bits = 32,
65 	.reg_stride = sizeof(u32),
66 	.max_register = 0x2B8,
67 	.volatile_reg = stm32_dfsdm_volatile_reg,
68 	.fast_io = true,
69 };
70 
71 static const struct stm32_dfsdm_dev_data stm32h7_dfsdm_data = {
72 	.num_filters = STM32H7_DFSDM_NUM_FILTERS,
73 	.num_channels = STM32H7_DFSDM_NUM_CHANNELS,
74 	.regmap_cfg = &stm32h7_dfsdm_regmap_cfg,
75 };
76 
77 static const struct regmap_config stm32mp1_dfsdm_regmap_cfg = {
78 	.reg_bits = 32,
79 	.val_bits = 32,
80 	.reg_stride = sizeof(u32),
81 	.max_register = 0x7fc,
82 	.volatile_reg = stm32_dfsdm_volatile_reg,
83 	.fast_io = true,
84 };
85 
86 static const struct stm32_dfsdm_dev_data stm32mp1_dfsdm_data = {
87 	.ipid = STM32MP15_IPIDR_NUMBER,
88 	.regmap_cfg = &stm32mp1_dfsdm_regmap_cfg,
89 };
90 
91 struct dfsdm_priv {
92 	struct platform_device *pdev; /* platform device */
93 
94 	struct stm32_dfsdm dfsdm; /* common data exported for all instances */
95 
96 	unsigned int spi_clk_out_div; /* SPI clkout divider value */
97 	atomic_t n_active_ch;	/* number of current active channels */
98 
99 	struct clk *clk; /* DFSDM clock */
100 	struct clk *aclk; /* audio clock */
101 };
102 
103 static inline struct dfsdm_priv *to_stm32_dfsdm_priv(struct stm32_dfsdm *dfsdm)
104 {
105 	return container_of(dfsdm, struct dfsdm_priv, dfsdm);
106 }
107 
108 static int stm32_dfsdm_clk_prepare_enable(struct stm32_dfsdm *dfsdm)
109 {
110 	struct dfsdm_priv *priv = to_stm32_dfsdm_priv(dfsdm);
111 	int ret;
112 
113 	ret = clk_prepare_enable(priv->clk);
114 	if (ret || !priv->aclk)
115 		return ret;
116 
117 	ret = clk_prepare_enable(priv->aclk);
118 	if (ret)
119 		clk_disable_unprepare(priv->clk);
120 
121 	return ret;
122 }
123 
124 static void stm32_dfsdm_clk_disable_unprepare(struct stm32_dfsdm *dfsdm)
125 {
126 	struct dfsdm_priv *priv = to_stm32_dfsdm_priv(dfsdm);
127 
128 	clk_disable_unprepare(priv->aclk);
129 	clk_disable_unprepare(priv->clk);
130 }
131 
132 /**
133  * stm32_dfsdm_start_dfsdm - start global dfsdm interface.
134  *
135  * Enable interface if n_active_ch is not null.
136  * @dfsdm: Handle used to retrieve dfsdm context.
137  */
138 int stm32_dfsdm_start_dfsdm(struct stm32_dfsdm *dfsdm)
139 {
140 	struct dfsdm_priv *priv = to_stm32_dfsdm_priv(dfsdm);
141 	struct device *dev = &priv->pdev->dev;
142 	unsigned int clk_div = priv->spi_clk_out_div, clk_src;
143 	int ret;
144 
145 	if (atomic_inc_return(&priv->n_active_ch) == 1) {
146 		ret = pm_runtime_resume_and_get(dev);
147 		if (ret < 0)
148 			goto error_ret;
149 
150 		/* select clock source, e.g. 0 for "dfsdm" or 1 for "audio" */
151 		clk_src = priv->aclk ? 1 : 0;
152 		ret = regmap_update_bits(dfsdm->regmap, DFSDM_CHCFGR1(0),
153 					 DFSDM_CHCFGR1_CKOUTSRC_MASK,
154 					 DFSDM_CHCFGR1_CKOUTSRC(clk_src));
155 		if (ret < 0)
156 			goto pm_put;
157 
158 		/* Output the SPI CLKOUT (if clk_div == 0 clock if OFF) */
159 		ret = regmap_update_bits(dfsdm->regmap, DFSDM_CHCFGR1(0),
160 					 DFSDM_CHCFGR1_CKOUTDIV_MASK,
161 					 DFSDM_CHCFGR1_CKOUTDIV(clk_div));
162 		if (ret < 0)
163 			goto pm_put;
164 
165 		/* Global enable of DFSDM interface */
166 		ret = regmap_update_bits(dfsdm->regmap, DFSDM_CHCFGR1(0),
167 					 DFSDM_CHCFGR1_DFSDMEN_MASK,
168 					 DFSDM_CHCFGR1_DFSDMEN(1));
169 		if (ret < 0)
170 			goto pm_put;
171 	}
172 
173 	dev_dbg(dev, "%s: n_active_ch %d\n", __func__,
174 		atomic_read(&priv->n_active_ch));
175 
176 	return 0;
177 
178 pm_put:
179 	pm_runtime_put_sync(dev);
180 error_ret:
181 	atomic_dec(&priv->n_active_ch);
182 
183 	return ret;
184 }
185 EXPORT_SYMBOL_GPL(stm32_dfsdm_start_dfsdm);
186 
187 /**
188  * stm32_dfsdm_stop_dfsdm - stop global DFSDM interface.
189  *
190  * Disable interface if n_active_ch is null
191  * @dfsdm: Handle used to retrieve dfsdm context.
192  */
193 int stm32_dfsdm_stop_dfsdm(struct stm32_dfsdm *dfsdm)
194 {
195 	struct dfsdm_priv *priv = to_stm32_dfsdm_priv(dfsdm);
196 	int ret;
197 
198 	if (atomic_dec_and_test(&priv->n_active_ch)) {
199 		/* Global disable of DFSDM interface */
200 		ret = regmap_update_bits(dfsdm->regmap, DFSDM_CHCFGR1(0),
201 					 DFSDM_CHCFGR1_DFSDMEN_MASK,
202 					 DFSDM_CHCFGR1_DFSDMEN(0));
203 		if (ret < 0)
204 			return ret;
205 
206 		/* Stop SPI CLKOUT */
207 		ret = regmap_update_bits(dfsdm->regmap, DFSDM_CHCFGR1(0),
208 					 DFSDM_CHCFGR1_CKOUTDIV_MASK,
209 					 DFSDM_CHCFGR1_CKOUTDIV(0));
210 		if (ret < 0)
211 			return ret;
212 
213 		pm_runtime_put_sync(&priv->pdev->dev);
214 	}
215 	dev_dbg(&priv->pdev->dev, "%s: n_active_ch %d\n", __func__,
216 		atomic_read(&priv->n_active_ch));
217 
218 	return 0;
219 }
220 EXPORT_SYMBOL_GPL(stm32_dfsdm_stop_dfsdm);
221 
222 static int stm32_dfsdm_parse_of(struct platform_device *pdev,
223 				struct dfsdm_priv *priv)
224 {
225 	struct device_node *node = pdev->dev.of_node;
226 	struct resource *res;
227 	unsigned long clk_freq, divider;
228 	unsigned int spi_freq, rem;
229 	int ret;
230 
231 	if (!node)
232 		return -EINVAL;
233 
234 	priv->dfsdm.base = devm_platform_get_and_ioremap_resource(pdev, 0,
235 							&res);
236 	if (IS_ERR(priv->dfsdm.base))
237 		return PTR_ERR(priv->dfsdm.base);
238 
239 	priv->dfsdm.phys_base = res->start;
240 
241 	/*
242 	 * "dfsdm" clock is mandatory for DFSDM peripheral clocking.
243 	 * "dfsdm" or "audio" clocks can be used as source clock for
244 	 * the SPI clock out signal and internal processing, depending
245 	 * on use case.
246 	 */
247 	priv->clk = devm_clk_get(&pdev->dev, "dfsdm");
248 	if (IS_ERR(priv->clk))
249 		return dev_err_probe(&pdev->dev, PTR_ERR(priv->clk),
250 				     "Failed to get clock\n");
251 
252 	priv->aclk = devm_clk_get(&pdev->dev, "audio");
253 	if (IS_ERR(priv->aclk))
254 		priv->aclk = NULL;
255 
256 	if (priv->aclk)
257 		clk_freq = clk_get_rate(priv->aclk);
258 	else
259 		clk_freq = clk_get_rate(priv->clk);
260 
261 	/* SPI clock out frequency */
262 	ret = of_property_read_u32(pdev->dev.of_node, "spi-max-frequency",
263 				   &spi_freq);
264 	if (ret < 0) {
265 		/* No SPI master mode */
266 		return 0;
267 	}
268 
269 	divider = div_u64_rem(clk_freq, spi_freq, &rem);
270 	/* Round up divider when ckout isn't precise, not to exceed spi_freq */
271 	if (rem)
272 		divider++;
273 
274 	/* programmable divider is in range of [2:256] */
275 	if (divider < 2 || divider > 256) {
276 		dev_err(&pdev->dev, "spi-max-frequency not achievable\n");
277 		return -EINVAL;
278 	}
279 
280 	/* SPI clock output divider is: divider = CKOUTDIV + 1 */
281 	priv->spi_clk_out_div = divider - 1;
282 	priv->dfsdm.spi_master_freq = clk_freq / (priv->spi_clk_out_div + 1);
283 
284 	if (rem) {
285 		dev_warn(&pdev->dev, "SPI clock not accurate\n");
286 		dev_warn(&pdev->dev, "%ld = %d * %d + %d\n",
287 			 clk_freq, spi_freq, priv->spi_clk_out_div + 1, rem);
288 	}
289 
290 	return 0;
291 };
292 
293 static const struct of_device_id stm32_dfsdm_of_match[] = {
294 	{
295 		.compatible = "st,stm32h7-dfsdm",
296 		.data = &stm32h7_dfsdm_data,
297 	},
298 	{
299 		.compatible = "st,stm32mp1-dfsdm",
300 		.data = &stm32mp1_dfsdm_data,
301 	},
302 	{}
303 };
304 MODULE_DEVICE_TABLE(of, stm32_dfsdm_of_match);
305 
306 static int stm32_dfsdm_probe_identification(struct platform_device *pdev,
307 					    struct dfsdm_priv *priv,
308 					    const struct stm32_dfsdm_dev_data *dev_data)
309 {
310 	struct device_node *np = pdev->dev.of_node;
311 	struct device_node *child;
312 	struct stm32_dfsdm *dfsdm = &priv->dfsdm;
313 	const char *compat;
314 	int ret, count = 0;
315 	u32 id, val;
316 
317 	if (!dev_data->ipid) {
318 		dfsdm->num_fls = dev_data->num_filters;
319 		dfsdm->num_chs = dev_data->num_channels;
320 		return 0;
321 	}
322 
323 	ret = regmap_read(dfsdm->regmap, DFSDM_IPIDR, &id);
324 	if (ret)
325 		return ret;
326 
327 	if (id != dev_data->ipid) {
328 		dev_err(&pdev->dev, "Unexpected IP version: 0x%x", id);
329 		return -EINVAL;
330 	}
331 
332 	for_each_child_of_node(np, child) {
333 		ret = of_property_read_string(child, "compatible", &compat);
334 		if (ret)
335 			continue;
336 		/* Count only child nodes with dfsdm compatible */
337 		if (strstr(compat, "dfsdm"))
338 			count++;
339 	}
340 
341 	ret = regmap_read(dfsdm->regmap, DFSDM_HWCFGR, &val);
342 	if (ret)
343 		return ret;
344 
345 	dfsdm->num_fls = FIELD_GET(DFSDM_HWCFGR_NBF_MASK, val);
346 	dfsdm->num_chs = FIELD_GET(DFSDM_HWCFGR_NBT_MASK, val);
347 
348 	if (count > dfsdm->num_fls) {
349 		dev_err(&pdev->dev, "Unexpected child number: %d", count);
350 		return -EINVAL;
351 	}
352 
353 	ret = regmap_read(dfsdm->regmap, DFSDM_VERR, &val);
354 	if (ret)
355 		return ret;
356 
357 	dev_dbg(&pdev->dev, "DFSDM version: %lu.%lu. %d channels/%d filters\n",
358 		FIELD_GET(DFSDM_VERR_MAJREV_MASK, val),
359 		FIELD_GET(DFSDM_VERR_MINREV_MASK, val),
360 		dfsdm->num_chs, dfsdm->num_fls);
361 
362 	return 0;
363 }
364 
365 static int stm32_dfsdm_probe(struct platform_device *pdev)
366 {
367 	struct dfsdm_priv *priv;
368 	const struct stm32_dfsdm_dev_data *dev_data;
369 	struct stm32_dfsdm *dfsdm;
370 	int ret;
371 
372 	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
373 	if (!priv)
374 		return -ENOMEM;
375 
376 	priv->pdev = pdev;
377 
378 	dev_data = of_device_get_match_data(&pdev->dev);
379 
380 	dfsdm = &priv->dfsdm;
381 
382 	ret = stm32_dfsdm_parse_of(pdev, priv);
383 	if (ret < 0)
384 		return ret;
385 
386 	dfsdm->regmap = devm_regmap_init_mmio_clk(&pdev->dev, "dfsdm",
387 						  dfsdm->base,
388 						  dev_data->regmap_cfg);
389 	if (IS_ERR(dfsdm->regmap)) {
390 		ret = PTR_ERR(dfsdm->regmap);
391 		dev_err(&pdev->dev, "%s: Failed to allocate regmap: %d\n",
392 			__func__, ret);
393 		return ret;
394 	}
395 
396 	ret = stm32_dfsdm_probe_identification(pdev, priv, dev_data);
397 	if (ret < 0)
398 		return ret;
399 
400 	dfsdm->fl_list = devm_kcalloc(&pdev->dev, dfsdm->num_fls,
401 				      sizeof(*dfsdm->fl_list), GFP_KERNEL);
402 	if (!dfsdm->fl_list)
403 		return -ENOMEM;
404 
405 	dfsdm->ch_list = devm_kcalloc(&pdev->dev, dfsdm->num_chs,
406 				      sizeof(*dfsdm->ch_list), GFP_KERNEL);
407 	if (!dfsdm->ch_list)
408 		return -ENOMEM;
409 
410 	platform_set_drvdata(pdev, dfsdm);
411 
412 	ret = stm32_dfsdm_clk_prepare_enable(dfsdm);
413 	if (ret) {
414 		dev_err(&pdev->dev, "Failed to start clock\n");
415 		return ret;
416 	}
417 
418 	pm_runtime_get_noresume(&pdev->dev);
419 	pm_runtime_set_active(&pdev->dev);
420 	pm_runtime_enable(&pdev->dev);
421 
422 	ret = of_platform_populate(pdev->dev.of_node, NULL, NULL, &pdev->dev);
423 	if (ret)
424 		goto pm_put;
425 
426 	pm_runtime_put(&pdev->dev);
427 
428 	return 0;
429 
430 pm_put:
431 	pm_runtime_disable(&pdev->dev);
432 	pm_runtime_set_suspended(&pdev->dev);
433 	pm_runtime_put_noidle(&pdev->dev);
434 	stm32_dfsdm_clk_disable_unprepare(dfsdm);
435 
436 	return ret;
437 }
438 
439 static int stm32_dfsdm_core_remove(struct platform_device *pdev)
440 {
441 	struct stm32_dfsdm *dfsdm = platform_get_drvdata(pdev);
442 
443 	pm_runtime_get_sync(&pdev->dev);
444 	of_platform_depopulate(&pdev->dev);
445 	pm_runtime_disable(&pdev->dev);
446 	pm_runtime_set_suspended(&pdev->dev);
447 	pm_runtime_put_noidle(&pdev->dev);
448 	stm32_dfsdm_clk_disable_unprepare(dfsdm);
449 
450 	return 0;
451 }
452 
453 static int stm32_dfsdm_core_suspend(struct device *dev)
454 {
455 	struct stm32_dfsdm *dfsdm = dev_get_drvdata(dev);
456 	struct dfsdm_priv *priv = to_stm32_dfsdm_priv(dfsdm);
457 	int ret;
458 
459 	ret = pm_runtime_force_suspend(dev);
460 	if (ret)
461 		return ret;
462 
463 	/* Balance devm_regmap_init_mmio_clk() clk_prepare() */
464 	clk_unprepare(priv->clk);
465 
466 	return pinctrl_pm_select_sleep_state(dev);
467 }
468 
469 static int stm32_dfsdm_core_resume(struct device *dev)
470 {
471 	struct stm32_dfsdm *dfsdm = dev_get_drvdata(dev);
472 	struct dfsdm_priv *priv = to_stm32_dfsdm_priv(dfsdm);
473 	int ret;
474 
475 	ret = pinctrl_pm_select_default_state(dev);
476 	if (ret)
477 		return ret;
478 
479 	ret = clk_prepare(priv->clk);
480 	if (ret)
481 		return ret;
482 
483 	return pm_runtime_force_resume(dev);
484 }
485 
486 static int stm32_dfsdm_core_runtime_suspend(struct device *dev)
487 {
488 	struct stm32_dfsdm *dfsdm = dev_get_drvdata(dev);
489 
490 	stm32_dfsdm_clk_disable_unprepare(dfsdm);
491 
492 	return 0;
493 }
494 
495 static int stm32_dfsdm_core_runtime_resume(struct device *dev)
496 {
497 	struct stm32_dfsdm *dfsdm = dev_get_drvdata(dev);
498 
499 	return stm32_dfsdm_clk_prepare_enable(dfsdm);
500 }
501 
502 static const struct dev_pm_ops stm32_dfsdm_core_pm_ops = {
503 	SYSTEM_SLEEP_PM_OPS(stm32_dfsdm_core_suspend, stm32_dfsdm_core_resume)
504 	RUNTIME_PM_OPS(stm32_dfsdm_core_runtime_suspend,
505 		       stm32_dfsdm_core_runtime_resume,
506 		       NULL)
507 };
508 
509 static struct platform_driver stm32_dfsdm_driver = {
510 	.probe = stm32_dfsdm_probe,
511 	.remove = stm32_dfsdm_core_remove,
512 	.driver = {
513 		.name = "stm32-dfsdm",
514 		.of_match_table = stm32_dfsdm_of_match,
515 		.pm = pm_ptr(&stm32_dfsdm_core_pm_ops),
516 	},
517 };
518 
519 module_platform_driver(stm32_dfsdm_driver);
520 
521 MODULE_AUTHOR("Arnaud Pouliquen <arnaud.pouliquen@st.com>");
522 MODULE_DESCRIPTION("STMicroelectronics STM32 dfsdm driver");
523 MODULE_LICENSE("GPL v2");
524