xref: /linux/drivers/soc/ti/smartreflex.c (revision 0da908c291070d89482f6211dbe81d4d43c3f7cb)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * OMAP SmartReflex Voltage Control
4  *
5  * Author: Thara Gopinath	<thara@ti.com>
6  *
7  * Copyright (C) 2012 Texas Instruments, Inc.
8  * Thara Gopinath <thara@ti.com>
9  *
10  * Copyright (C) 2008 Nokia Corporation
11  * Kalle Jokiniemi
12  *
13  * Copyright (C) 2007 Texas Instruments, Inc.
14  * Lesly A M <x0080970@ti.com>
15  */
16 
17 #include <linux/module.h>
18 #include <linux/mod_devicetable.h>
19 #include <linux/interrupt.h>
20 #include <linux/clk.h>
21 #include <linux/io.h>
22 #include <linux/debugfs.h>
23 #include <linux/delay.h>
24 #include <linux/slab.h>
25 #include <linux/pm_runtime.h>
26 #include <linux/power/smartreflex.h>
27 
28 #define DRIVER_NAME	"smartreflex"
29 #define SMARTREFLEX_NAME_LEN	32
30 #define NVALUE_NAME_LEN		40
31 #define SR_DISABLE_TIMEOUT	200
32 
33 /* sr_list contains all the instances of smartreflex module */
34 static LIST_HEAD(sr_list);
35 
36 static struct omap_sr_class_data *sr_class;
37 static struct dentry		*sr_dbg_dir;
38 
39 static inline void sr_write_reg(struct omap_sr *sr, unsigned offset, u32 value)
40 {
41 	__raw_writel(value, (sr->base + offset));
42 }
43 
44 static inline void sr_modify_reg(struct omap_sr *sr, unsigned offset, u32 mask,
45 					u32 value)
46 {
47 	u32 reg_val;
48 
49 	/*
50 	 * Smartreflex error config register is special as it contains
51 	 * certain status bits which if written a 1 into means a clear
52 	 * of those bits. So in order to make sure no accidental write of
53 	 * 1 happens to those status bits, do a clear of them in the read
54 	 * value. This mean this API doesn't rewrite values in these bits
55 	 * if they are currently set, but does allow the caller to write
56 	 * those bits.
57 	 */
58 	if (sr->ip_type == SR_TYPE_V1 && offset == ERRCONFIG_V1)
59 		mask |= ERRCONFIG_STATUS_V1_MASK;
60 	else if (sr->ip_type == SR_TYPE_V2 && offset == ERRCONFIG_V2)
61 		mask |= ERRCONFIG_VPBOUNDINTST_V2;
62 
63 	reg_val = __raw_readl(sr->base + offset);
64 	reg_val &= ~mask;
65 
66 	value &= mask;
67 
68 	reg_val |= value;
69 
70 	__raw_writel(reg_val, (sr->base + offset));
71 }
72 
73 static inline u32 sr_read_reg(struct omap_sr *sr, unsigned offset)
74 {
75 	return __raw_readl(sr->base + offset);
76 }
77 
78 static struct omap_sr *_sr_lookup(struct voltagedomain *voltdm)
79 {
80 	struct omap_sr *sr_info;
81 
82 	if (!voltdm) {
83 		pr_err("%s: Null voltage domain passed!\n", __func__);
84 		return ERR_PTR(-EINVAL);
85 	}
86 
87 	list_for_each_entry(sr_info, &sr_list, node) {
88 		if (voltdm == sr_info->voltdm)
89 			return sr_info;
90 	}
91 
92 	return ERR_PTR(-ENODATA);
93 }
94 
95 static irqreturn_t sr_interrupt(int irq, void *data)
96 {
97 	struct omap_sr *sr_info = data;
98 	u32 status = 0;
99 
100 	switch (sr_info->ip_type) {
101 	case SR_TYPE_V1:
102 		/* Read the status bits */
103 		status = sr_read_reg(sr_info, ERRCONFIG_V1);
104 
105 		/* Clear them by writing back */
106 		sr_write_reg(sr_info, ERRCONFIG_V1, status);
107 		break;
108 	case SR_TYPE_V2:
109 		/* Read the status bits */
110 		status = sr_read_reg(sr_info, IRQSTATUS);
111 
112 		/* Clear them by writing back */
113 		sr_write_reg(sr_info, IRQSTATUS, status);
114 		break;
115 	default:
116 		dev_err(&sr_info->pdev->dev, "UNKNOWN IP type %d\n",
117 			sr_info->ip_type);
118 		return IRQ_NONE;
119 	}
120 
121 	if (sr_class->notify)
122 		sr_class->notify(sr_info, status);
123 
124 	return IRQ_HANDLED;
125 }
126 
127 static void sr_set_clk_length(struct omap_sr *sr)
128 {
129 	u32 fclk_speed;
130 
131 	/* Try interconnect target module fck first if it already exists */
132 	if (IS_ERR(sr->fck))
133 		return;
134 
135 	fclk_speed = clk_get_rate(sr->fck);
136 
137 	switch (fclk_speed) {
138 	case 12000000:
139 		sr->clk_length = SRCLKLENGTH_12MHZ_SYSCLK;
140 		break;
141 	case 13000000:
142 		sr->clk_length = SRCLKLENGTH_13MHZ_SYSCLK;
143 		break;
144 	case 19200000:
145 		sr->clk_length = SRCLKLENGTH_19MHZ_SYSCLK;
146 		break;
147 	case 26000000:
148 		sr->clk_length = SRCLKLENGTH_26MHZ_SYSCLK;
149 		break;
150 	case 38400000:
151 		sr->clk_length = SRCLKLENGTH_38MHZ_SYSCLK;
152 		break;
153 	default:
154 		dev_err(&sr->pdev->dev, "%s: Invalid fclk rate: %d\n",
155 			__func__, fclk_speed);
156 		break;
157 	}
158 }
159 
160 static void sr_start_vddautocomp(struct omap_sr *sr)
161 {
162 	if (!sr_class || !(sr_class->enable) || !(sr_class->configure)) {
163 		dev_warn(&sr->pdev->dev,
164 			 "%s: smartreflex class driver not registered\n",
165 			 __func__);
166 		return;
167 	}
168 
169 	if (!sr_class->enable(sr))
170 		sr->autocomp_active = true;
171 }
172 
173 static void sr_stop_vddautocomp(struct omap_sr *sr)
174 {
175 	if (!sr_class || !(sr_class->disable)) {
176 		dev_warn(&sr->pdev->dev,
177 			 "%s: smartreflex class driver not registered\n",
178 			 __func__);
179 		return;
180 	}
181 
182 	if (sr->autocomp_active) {
183 		sr_class->disable(sr, 1);
184 		sr->autocomp_active = false;
185 	}
186 }
187 
188 /*
189  * This function handles the initializations which have to be done
190  * only when both sr device and class driver regiter has
191  * completed. This will be attempted to be called from both sr class
192  * driver register and sr device intializtion API's. Only one call
193  * will ultimately succeed.
194  *
195  * Currently this function registers interrupt handler for a particular SR
196  * if smartreflex class driver is already registered and has
197  * requested for interrupts and the SR interrupt line in present.
198  */
199 static int sr_late_init(struct omap_sr *sr_info)
200 {
201 	struct omap_sr_data *pdata = sr_info->pdev->dev.platform_data;
202 	int ret = 0;
203 
204 	if (sr_class->notify && sr_class->notify_flags && sr_info->irq) {
205 		ret = devm_request_irq(&sr_info->pdev->dev, sr_info->irq,
206 				       sr_interrupt, 0, sr_info->name, sr_info);
207 		if (ret)
208 			goto error;
209 		disable_irq(sr_info->irq);
210 	}
211 
212 	if (pdata && pdata->enable_on_init)
213 		sr_start_vddautocomp(sr_info);
214 
215 	return ret;
216 
217 error:
218 	list_del(&sr_info->node);
219 	dev_err(&sr_info->pdev->dev, "%s: ERROR in registering interrupt handler. Smartreflex will not function as desired\n",
220 		__func__);
221 
222 	return ret;
223 }
224 
225 static void sr_v1_disable(struct omap_sr *sr)
226 {
227 	int timeout = 0;
228 	int errconf_val = ERRCONFIG_MCUACCUMINTST | ERRCONFIG_MCUVALIDINTST |
229 			ERRCONFIG_MCUBOUNDINTST;
230 
231 	/* Enable MCUDisableAcknowledge interrupt */
232 	sr_modify_reg(sr, ERRCONFIG_V1,
233 			ERRCONFIG_MCUDISACKINTEN, ERRCONFIG_MCUDISACKINTEN);
234 
235 	/* SRCONFIG - disable SR */
236 	sr_modify_reg(sr, SRCONFIG, SRCONFIG_SRENABLE, 0x0);
237 
238 	/* Disable all other SR interrupts and clear the status as needed */
239 	if (sr_read_reg(sr, ERRCONFIG_V1) & ERRCONFIG_VPBOUNDINTST_V1)
240 		errconf_val |= ERRCONFIG_VPBOUNDINTST_V1;
241 	sr_modify_reg(sr, ERRCONFIG_V1,
242 			(ERRCONFIG_MCUACCUMINTEN | ERRCONFIG_MCUVALIDINTEN |
243 			ERRCONFIG_MCUBOUNDINTEN | ERRCONFIG_VPBOUNDINTEN_V1),
244 			errconf_val);
245 
246 	/*
247 	 * Wait for SR to be disabled.
248 	 * wait until ERRCONFIG.MCUDISACKINTST = 1. Typical latency is 1us.
249 	 */
250 	sr_test_cond_timeout((sr_read_reg(sr, ERRCONFIG_V1) &
251 			     ERRCONFIG_MCUDISACKINTST), SR_DISABLE_TIMEOUT,
252 			     timeout);
253 
254 	if (timeout >= SR_DISABLE_TIMEOUT)
255 		dev_warn(&sr->pdev->dev, "%s: Smartreflex disable timedout\n",
256 			 __func__);
257 
258 	/* Disable MCUDisableAcknowledge interrupt & clear pending interrupt */
259 	sr_modify_reg(sr, ERRCONFIG_V1, ERRCONFIG_MCUDISACKINTEN,
260 			ERRCONFIG_MCUDISACKINTST);
261 }
262 
263 static void sr_v2_disable(struct omap_sr *sr)
264 {
265 	int timeout = 0;
266 
267 	/* Enable MCUDisableAcknowledge interrupt */
268 	sr_write_reg(sr, IRQENABLE_SET, IRQENABLE_MCUDISABLEACKINT);
269 
270 	/* SRCONFIG - disable SR */
271 	sr_modify_reg(sr, SRCONFIG, SRCONFIG_SRENABLE, 0x0);
272 
273 	/*
274 	 * Disable all other SR interrupts and clear the status
275 	 * write to status register ONLY on need basis - only if status
276 	 * is set.
277 	 */
278 	if (sr_read_reg(sr, ERRCONFIG_V2) & ERRCONFIG_VPBOUNDINTST_V2)
279 		sr_modify_reg(sr, ERRCONFIG_V2, ERRCONFIG_VPBOUNDINTEN_V2,
280 			ERRCONFIG_VPBOUNDINTST_V2);
281 	else
282 		sr_modify_reg(sr, ERRCONFIG_V2, ERRCONFIG_VPBOUNDINTEN_V2,
283 				0x0);
284 	sr_write_reg(sr, IRQENABLE_CLR, (IRQENABLE_MCUACCUMINT |
285 			IRQENABLE_MCUVALIDINT |
286 			IRQENABLE_MCUBOUNDSINT));
287 	sr_write_reg(sr, IRQSTATUS, (IRQSTATUS_MCUACCUMINT |
288 			IRQSTATUS_MCVALIDINT |
289 			IRQSTATUS_MCBOUNDSINT));
290 
291 	/*
292 	 * Wait for SR to be disabled.
293 	 * wait until IRQSTATUS.MCUDISACKINTST = 1. Typical latency is 1us.
294 	 */
295 	sr_test_cond_timeout((sr_read_reg(sr, IRQSTATUS) &
296 			     IRQSTATUS_MCUDISABLEACKINT), SR_DISABLE_TIMEOUT,
297 			     timeout);
298 
299 	if (timeout >= SR_DISABLE_TIMEOUT)
300 		dev_warn(&sr->pdev->dev, "%s: Smartreflex disable timedout\n",
301 			 __func__);
302 
303 	/* Disable MCUDisableAcknowledge interrupt & clear pending interrupt */
304 	sr_write_reg(sr, IRQENABLE_CLR, IRQENABLE_MCUDISABLEACKINT);
305 	sr_write_reg(sr, IRQSTATUS, IRQSTATUS_MCUDISABLEACKINT);
306 }
307 
308 static struct omap_sr_nvalue_table *sr_retrieve_nvalue_row(
309 				struct omap_sr *sr, u32 efuse_offs)
310 {
311 	int i;
312 
313 	if (!sr->nvalue_table) {
314 		dev_warn(&sr->pdev->dev, "%s: Missing ntarget value table\n",
315 			 __func__);
316 		return NULL;
317 	}
318 
319 	for (i = 0; i < sr->nvalue_count; i++) {
320 		if (sr->nvalue_table[i].efuse_offs == efuse_offs)
321 			return &sr->nvalue_table[i];
322 	}
323 
324 	return NULL;
325 }
326 
327 /* Public Functions */
328 
329 /**
330  * sr_configure_errgen() - Configures the SmartReflex to perform AVS using the
331  *			 error generator module.
332  * @sr:			SR module to be configured.
333  *
334  * This API is to be called from the smartreflex class driver to
335  * configure the error generator module inside the smartreflex module.
336  * SR settings if using the ERROR module inside Smartreflex.
337  * SR CLASS 3 by default uses only the ERROR module where as
338  * SR CLASS 2 can choose between ERROR module and MINMAXAVG
339  * module. Returns 0 on success and error value in case of failure.
340  */
341 int sr_configure_errgen(struct omap_sr *sr)
342 {
343 	u32 sr_config, sr_errconfig, errconfig_offs;
344 	u32 vpboundint_en, vpboundint_st;
345 	u32 senp_en = 0, senn_en = 0;
346 	u8 senp_shift, senn_shift;
347 
348 	if (!sr) {
349 		pr_warn("%s: NULL omap_sr from %pS\n",
350 			__func__, (void *)_RET_IP_);
351 		return -EINVAL;
352 	}
353 
354 	if (!sr->clk_length)
355 		sr_set_clk_length(sr);
356 
357 	senp_en = sr->senp_mod;
358 	senn_en = sr->senn_mod;
359 
360 	sr_config = (sr->clk_length << SRCONFIG_SRCLKLENGTH_SHIFT) |
361 		SRCONFIG_SENENABLE | SRCONFIG_ERRGEN_EN;
362 
363 	switch (sr->ip_type) {
364 	case SR_TYPE_V1:
365 		sr_config |= SRCONFIG_DELAYCTRL;
366 		senn_shift = SRCONFIG_SENNENABLE_V1_SHIFT;
367 		senp_shift = SRCONFIG_SENPENABLE_V1_SHIFT;
368 		errconfig_offs = ERRCONFIG_V1;
369 		vpboundint_en = ERRCONFIG_VPBOUNDINTEN_V1;
370 		vpboundint_st = ERRCONFIG_VPBOUNDINTST_V1;
371 		break;
372 	case SR_TYPE_V2:
373 		senn_shift = SRCONFIG_SENNENABLE_V2_SHIFT;
374 		senp_shift = SRCONFIG_SENPENABLE_V2_SHIFT;
375 		errconfig_offs = ERRCONFIG_V2;
376 		vpboundint_en = ERRCONFIG_VPBOUNDINTEN_V2;
377 		vpboundint_st = ERRCONFIG_VPBOUNDINTST_V2;
378 		break;
379 	default:
380 		dev_err(&sr->pdev->dev, "%s: Trying to Configure smartreflex module without specifying the ip\n",
381 			__func__);
382 		return -EINVAL;
383 	}
384 
385 	sr_config |= ((senn_en << senn_shift) | (senp_en << senp_shift));
386 	sr_write_reg(sr, SRCONFIG, sr_config);
387 	sr_errconfig = (sr->err_weight << ERRCONFIG_ERRWEIGHT_SHIFT) |
388 		(sr->err_maxlimit << ERRCONFIG_ERRMAXLIMIT_SHIFT) |
389 		(sr->err_minlimit <<  ERRCONFIG_ERRMINLIMIT_SHIFT);
390 	sr_modify_reg(sr, errconfig_offs, (SR_ERRWEIGHT_MASK |
391 		SR_ERRMAXLIMIT_MASK | SR_ERRMINLIMIT_MASK),
392 		sr_errconfig);
393 
394 	/* Enabling the interrupts if the ERROR module is used */
395 	sr_modify_reg(sr, errconfig_offs, (vpboundint_en | vpboundint_st),
396 		      vpboundint_en);
397 
398 	return 0;
399 }
400 
401 /**
402  * sr_disable_errgen() - Disables SmartReflex AVS module's errgen component
403  * @sr:			SR module to be configured.
404  *
405  * This API is to be called from the smartreflex class driver to
406  * disable the error generator module inside the smartreflex module.
407  *
408  * Returns 0 on success and error value in case of failure.
409  */
410 int sr_disable_errgen(struct omap_sr *sr)
411 {
412 	u32 errconfig_offs;
413 	u32 vpboundint_en, vpboundint_st;
414 
415 	if (!sr) {
416 		pr_warn("%s: NULL omap_sr from %pS\n",
417 			__func__, (void *)_RET_IP_);
418 		return -EINVAL;
419 	}
420 
421 	switch (sr->ip_type) {
422 	case SR_TYPE_V1:
423 		errconfig_offs = ERRCONFIG_V1;
424 		vpboundint_en = ERRCONFIG_VPBOUNDINTEN_V1;
425 		vpboundint_st = ERRCONFIG_VPBOUNDINTST_V1;
426 		break;
427 	case SR_TYPE_V2:
428 		errconfig_offs = ERRCONFIG_V2;
429 		vpboundint_en = ERRCONFIG_VPBOUNDINTEN_V2;
430 		vpboundint_st = ERRCONFIG_VPBOUNDINTST_V2;
431 		break;
432 	default:
433 		dev_err(&sr->pdev->dev, "%s: Trying to Configure smartreflex module without specifying the ip\n",
434 			__func__);
435 		return -EINVAL;
436 	}
437 
438 	/* Disable the Sensor and errorgen */
439 	sr_modify_reg(sr, SRCONFIG, SRCONFIG_SENENABLE | SRCONFIG_ERRGEN_EN, 0);
440 
441 	/*
442 	 * Disable the interrupts of ERROR module
443 	 * NOTE: modify is a read, modify,write - an implicit OCP barrier
444 	 * which is required is present here - sequencing is critical
445 	 * at this point (after errgen is disabled, vpboundint disable)
446 	 */
447 	sr_modify_reg(sr, errconfig_offs, vpboundint_en | vpboundint_st, 0);
448 
449 	return 0;
450 }
451 
452 /**
453  * sr_configure_minmax() - Configures the SmartReflex to perform AVS using the
454  *			 minmaxavg module.
455  * @sr:			SR module to be configured.
456  *
457  * This API is to be called from the smartreflex class driver to
458  * configure the minmaxavg module inside the smartreflex module.
459  * SR settings if using the ERROR module inside Smartreflex.
460  * SR CLASS 3 by default uses only the ERROR module where as
461  * SR CLASS 2 can choose between ERROR module and MINMAXAVG
462  * module. Returns 0 on success and error value in case of failure.
463  */
464 int sr_configure_minmax(struct omap_sr *sr)
465 {
466 	u32 sr_config, sr_avgwt;
467 	u32 senp_en = 0, senn_en = 0;
468 	u8 senp_shift, senn_shift;
469 
470 	if (!sr) {
471 		pr_warn("%s: NULL omap_sr from %pS\n",
472 			__func__, (void *)_RET_IP_);
473 		return -EINVAL;
474 	}
475 
476 	if (!sr->clk_length)
477 		sr_set_clk_length(sr);
478 
479 	senp_en = sr->senp_mod;
480 	senn_en = sr->senn_mod;
481 
482 	sr_config = (sr->clk_length << SRCONFIG_SRCLKLENGTH_SHIFT) |
483 		SRCONFIG_SENENABLE |
484 		(sr->accum_data << SRCONFIG_ACCUMDATA_SHIFT);
485 
486 	switch (sr->ip_type) {
487 	case SR_TYPE_V1:
488 		sr_config |= SRCONFIG_DELAYCTRL;
489 		senn_shift = SRCONFIG_SENNENABLE_V1_SHIFT;
490 		senp_shift = SRCONFIG_SENPENABLE_V1_SHIFT;
491 		break;
492 	case SR_TYPE_V2:
493 		senn_shift = SRCONFIG_SENNENABLE_V2_SHIFT;
494 		senp_shift = SRCONFIG_SENPENABLE_V2_SHIFT;
495 		break;
496 	default:
497 		dev_err(&sr->pdev->dev, "%s: Trying to Configure smartreflex module without specifying the ip\n",
498 			__func__);
499 		return -EINVAL;
500 	}
501 
502 	sr_config |= ((senn_en << senn_shift) | (senp_en << senp_shift));
503 	sr_write_reg(sr, SRCONFIG, sr_config);
504 	sr_avgwt = (sr->senp_avgweight << AVGWEIGHT_SENPAVGWEIGHT_SHIFT) |
505 		(sr->senn_avgweight << AVGWEIGHT_SENNAVGWEIGHT_SHIFT);
506 	sr_write_reg(sr, AVGWEIGHT, sr_avgwt);
507 
508 	/*
509 	 * Enabling the interrupts if MINMAXAVG module is used.
510 	 * TODO: check if all the interrupts are mandatory
511 	 */
512 	switch (sr->ip_type) {
513 	case SR_TYPE_V1:
514 		sr_modify_reg(sr, ERRCONFIG_V1,
515 			(ERRCONFIG_MCUACCUMINTEN | ERRCONFIG_MCUVALIDINTEN |
516 			ERRCONFIG_MCUBOUNDINTEN),
517 			(ERRCONFIG_MCUACCUMINTEN | ERRCONFIG_MCUACCUMINTST |
518 			 ERRCONFIG_MCUVALIDINTEN | ERRCONFIG_MCUVALIDINTST |
519 			 ERRCONFIG_MCUBOUNDINTEN | ERRCONFIG_MCUBOUNDINTST));
520 		break;
521 	case SR_TYPE_V2:
522 		sr_write_reg(sr, IRQSTATUS,
523 			IRQSTATUS_MCUACCUMINT | IRQSTATUS_MCVALIDINT |
524 			IRQSTATUS_MCBOUNDSINT | IRQSTATUS_MCUDISABLEACKINT);
525 		sr_write_reg(sr, IRQENABLE_SET,
526 			IRQENABLE_MCUACCUMINT | IRQENABLE_MCUVALIDINT |
527 			IRQENABLE_MCUBOUNDSINT | IRQENABLE_MCUDISABLEACKINT);
528 		break;
529 	default:
530 		dev_err(&sr->pdev->dev, "%s: Trying to Configure smartreflex module without specifying the ip\n",
531 			__func__);
532 		return -EINVAL;
533 	}
534 
535 	return 0;
536 }
537 
538 /**
539  * sr_enable() - Enables the smartreflex module.
540  * @sr:		pointer to which the SR module to be configured belongs to.
541  * @volt:	The voltage at which the Voltage domain associated with
542  *		the smartreflex module is operating at.
543  *		This is required only to program the correct Ntarget value.
544  *
545  * This API is to be called from the smartreflex class driver to
546  * enable a smartreflex module. Returns 0 on success. Returns error
547  * value if the voltage passed is wrong or if ntarget value is wrong.
548  */
549 int sr_enable(struct omap_sr *sr, unsigned long volt)
550 {
551 	struct omap_volt_data *volt_data;
552 	struct omap_sr_nvalue_table *nvalue_row;
553 	int ret;
554 
555 	if (!sr) {
556 		pr_warn("%s: NULL omap_sr from %pS\n",
557 			__func__, (void *)_RET_IP_);
558 		return -EINVAL;
559 	}
560 
561 	volt_data = omap_voltage_get_voltdata(sr->voltdm, volt);
562 
563 	if (IS_ERR(volt_data)) {
564 		dev_warn(&sr->pdev->dev, "%s: Unable to get voltage table for nominal voltage %ld\n",
565 			 __func__, volt);
566 		return PTR_ERR(volt_data);
567 	}
568 
569 	nvalue_row = sr_retrieve_nvalue_row(sr, volt_data->sr_efuse_offs);
570 
571 	if (!nvalue_row) {
572 		dev_warn(&sr->pdev->dev, "%s: failure getting SR data for this voltage %ld\n",
573 			 __func__, volt);
574 		return -ENODATA;
575 	}
576 
577 	/* errminlimit is opp dependent and hence linked to voltage */
578 	sr->err_minlimit = nvalue_row->errminlimit;
579 
580 	clk_enable(sr->fck);
581 
582 	/* Check if SR is already enabled. If yes do nothing */
583 	if (sr_read_reg(sr, SRCONFIG) & SRCONFIG_SRENABLE)
584 		goto out_enabled;
585 
586 	/* Configure SR */
587 	ret = sr_class->configure(sr);
588 	if (ret)
589 		goto out_enabled;
590 
591 	sr_write_reg(sr, NVALUERECIPROCAL, nvalue_row->nvalue);
592 
593 	/* SRCONFIG - enable SR */
594 	sr_modify_reg(sr, SRCONFIG, SRCONFIG_SRENABLE, SRCONFIG_SRENABLE);
595 
596 out_enabled:
597 	sr->enabled = 1;
598 
599 	return 0;
600 }
601 
602 /**
603  * sr_disable() - Disables the smartreflex module.
604  * @sr:		pointer to which the SR module to be configured belongs to.
605  *
606  * This API is to be called from the smartreflex class driver to
607  * disable a smartreflex module.
608  */
609 void sr_disable(struct omap_sr *sr)
610 {
611 	if (!sr) {
612 		pr_warn("%s: NULL omap_sr from %pS\n",
613 			__func__, (void *)_RET_IP_);
614 		return;
615 	}
616 
617 	/* Check if SR clocks are already disabled. If yes do nothing */
618 	if (!sr->enabled)
619 		return;
620 
621 	/*
622 	 * Disable SR if only it is indeed enabled. Else just
623 	 * disable the clocks.
624 	 */
625 	if (sr_read_reg(sr, SRCONFIG) & SRCONFIG_SRENABLE) {
626 		switch (sr->ip_type) {
627 		case SR_TYPE_V1:
628 			sr_v1_disable(sr);
629 			break;
630 		case SR_TYPE_V2:
631 			sr_v2_disable(sr);
632 			break;
633 		default:
634 			dev_err(&sr->pdev->dev, "UNKNOWN IP type %d\n",
635 				sr->ip_type);
636 		}
637 	}
638 
639 	clk_disable(sr->fck);
640 	sr->enabled = 0;
641 }
642 
643 /**
644  * sr_register_class() - API to register a smartreflex class parameters.
645  * @class_data:	The structure containing various sr class specific data.
646  *
647  * This API is to be called by the smartreflex class driver to register itself
648  * with the smartreflex driver during init. Returns 0 on success else the
649  * error value.
650  */
651 int sr_register_class(struct omap_sr_class_data *class_data)
652 {
653 	struct omap_sr *sr_info;
654 
655 	if (!class_data) {
656 		pr_warn("%s:, Smartreflex class data passed is NULL\n",
657 			__func__);
658 		return -EINVAL;
659 	}
660 
661 	if (sr_class) {
662 		pr_warn("%s: Smartreflex class driver already registered\n",
663 			__func__);
664 		return -EBUSY;
665 	}
666 
667 	sr_class = class_data;
668 
669 	/*
670 	 * Call into late init to do initializations that require
671 	 * both sr driver and sr class driver to be initiallized.
672 	 */
673 	list_for_each_entry(sr_info, &sr_list, node)
674 		sr_late_init(sr_info);
675 
676 	return 0;
677 }
678 
679 /**
680  * omap_sr_enable() -  API to enable SR clocks and to call into the
681  *			registered smartreflex class enable API.
682  * @voltdm:	VDD pointer to which the SR module to be configured belongs to.
683  *
684  * This API is to be called from the kernel in order to enable
685  * a particular smartreflex module. This API will do the initial
686  * configurations to turn on the smartreflex module and in turn call
687  * into the registered smartreflex class enable API.
688  */
689 void omap_sr_enable(struct voltagedomain *voltdm)
690 {
691 	struct omap_sr *sr = _sr_lookup(voltdm);
692 
693 	if (IS_ERR(sr)) {
694 		pr_warn("%s: omap_sr struct for voltdm not found\n", __func__);
695 		return;
696 	}
697 
698 	if (!sr->autocomp_active)
699 		return;
700 
701 	if (!sr_class || !(sr_class->enable) || !(sr_class->configure)) {
702 		dev_warn(&sr->pdev->dev, "%s: smartreflex class driver not registered\n",
703 			 __func__);
704 		return;
705 	}
706 
707 	sr_class->enable(sr);
708 }
709 
710 /**
711  * omap_sr_disable() - API to disable SR without resetting the voltage
712  *			processor voltage
713  * @voltdm:	VDD pointer to which the SR module to be configured belongs to.
714  *
715  * This API is to be called from the kernel in order to disable
716  * a particular smartreflex module. This API will in turn call
717  * into the registered smartreflex class disable API. This API will tell
718  * the smartreflex class disable not to reset the VP voltage after
719  * disabling smartreflex.
720  */
721 void omap_sr_disable(struct voltagedomain *voltdm)
722 {
723 	struct omap_sr *sr = _sr_lookup(voltdm);
724 
725 	if (IS_ERR(sr)) {
726 		pr_warn("%s: omap_sr struct for voltdm not found\n", __func__);
727 		return;
728 	}
729 
730 	if (!sr->autocomp_active)
731 		return;
732 
733 	if (!sr_class || !(sr_class->disable)) {
734 		dev_warn(&sr->pdev->dev, "%s: smartreflex class driver not registered\n",
735 			 __func__);
736 		return;
737 	}
738 
739 	sr_class->disable(sr, 0);
740 }
741 
742 /**
743  * omap_sr_disable_reset_volt() - API to disable SR and reset the
744  *				voltage processor voltage
745  * @voltdm:	VDD pointer to which the SR module to be configured belongs to.
746  *
747  * This API is to be called from the kernel in order to disable
748  * a particular smartreflex module. This API will in turn call
749  * into the registered smartreflex class disable API. This API will tell
750  * the smartreflex class disable to reset the VP voltage after
751  * disabling smartreflex.
752  */
753 void omap_sr_disable_reset_volt(struct voltagedomain *voltdm)
754 {
755 	struct omap_sr *sr = _sr_lookup(voltdm);
756 
757 	if (IS_ERR(sr)) {
758 		pr_warn("%s: omap_sr struct for voltdm not found\n", __func__);
759 		return;
760 	}
761 
762 	if (!sr->autocomp_active)
763 		return;
764 
765 	if (!sr_class || !(sr_class->disable)) {
766 		dev_warn(&sr->pdev->dev, "%s: smartreflex class driver not registered\n",
767 			 __func__);
768 		return;
769 	}
770 
771 	sr_class->disable(sr, 1);
772 }
773 
774 /* PM Debug FS entries to enable and disable smartreflex. */
775 static int omap_sr_autocomp_show(void *data, u64 *val)
776 {
777 	struct omap_sr *sr_info = data;
778 
779 	if (!sr_info) {
780 		pr_warn("%s: omap_sr struct not found\n", __func__);
781 		return -EINVAL;
782 	}
783 
784 	*val = sr_info->autocomp_active;
785 
786 	return 0;
787 }
788 
789 static int omap_sr_autocomp_store(void *data, u64 val)
790 {
791 	struct omap_sr *sr_info = data;
792 
793 	if (!sr_info) {
794 		pr_warn("%s: omap_sr struct not found\n", __func__);
795 		return -EINVAL;
796 	}
797 
798 	/* Sanity check */
799 	if (val > 1) {
800 		pr_warn("%s: Invalid argument %lld\n", __func__, val);
801 		return -EINVAL;
802 	}
803 
804 	/* control enable/disable only if there is a delta in value */
805 	if (sr_info->autocomp_active != val) {
806 		if (!val)
807 			sr_stop_vddautocomp(sr_info);
808 		else
809 			sr_start_vddautocomp(sr_info);
810 	}
811 
812 	return 0;
813 }
814 
815 DEFINE_SIMPLE_ATTRIBUTE(pm_sr_fops, omap_sr_autocomp_show,
816 			omap_sr_autocomp_store, "%llu\n");
817 
818 static int omap_sr_probe(struct platform_device *pdev)
819 {
820 	struct omap_sr *sr_info;
821 	struct omap_sr_data *pdata = pdev->dev.platform_data;
822 	struct resource *mem;
823 	struct dentry *nvalue_dir;
824 	int i, ret = 0;
825 
826 	sr_info = devm_kzalloc(&pdev->dev, sizeof(struct omap_sr), GFP_KERNEL);
827 	if (!sr_info)
828 		return -ENOMEM;
829 
830 	sr_info->name = devm_kzalloc(&pdev->dev,
831 				     SMARTREFLEX_NAME_LEN, GFP_KERNEL);
832 	if (!sr_info->name)
833 		return -ENOMEM;
834 
835 	platform_set_drvdata(pdev, sr_info);
836 
837 	if (!pdata) {
838 		dev_err(&pdev->dev, "%s: platform data missing\n", __func__);
839 		return -EINVAL;
840 	}
841 
842 	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
843 	sr_info->base = devm_ioremap_resource(&pdev->dev, mem);
844 	if (IS_ERR(sr_info->base))
845 		return PTR_ERR(sr_info->base);
846 
847 	ret = platform_get_irq_optional(pdev, 0);
848 	if (ret < 0 && ret != -ENXIO)
849 		return dev_err_probe(&pdev->dev, ret, "failed to get IRQ resource\n");
850 	if (ret > 0)
851 		sr_info->irq = ret;
852 
853 	sr_info->fck = devm_clk_get(pdev->dev.parent, "fck");
854 	if (IS_ERR(sr_info->fck))
855 		return PTR_ERR(sr_info->fck);
856 	clk_prepare(sr_info->fck);
857 
858 	pm_runtime_enable(&pdev->dev);
859 
860 	snprintf(sr_info->name, SMARTREFLEX_NAME_LEN, "%s", pdata->name);
861 
862 	sr_info->pdev = pdev;
863 	sr_info->srid = pdev->id;
864 	sr_info->voltdm = pdata->voltdm;
865 	sr_info->nvalue_table = pdata->nvalue_table;
866 	sr_info->nvalue_count = pdata->nvalue_count;
867 	sr_info->senn_mod = pdata->senn_mod;
868 	sr_info->senp_mod = pdata->senp_mod;
869 	sr_info->err_weight = pdata->err_weight;
870 	sr_info->err_maxlimit = pdata->err_maxlimit;
871 	sr_info->accum_data = pdata->accum_data;
872 	sr_info->senn_avgweight = pdata->senn_avgweight;
873 	sr_info->senp_avgweight = pdata->senp_avgweight;
874 	sr_info->autocomp_active = false;
875 	sr_info->ip_type = pdata->ip_type;
876 
877 	sr_set_clk_length(sr_info);
878 
879 	list_add(&sr_info->node, &sr_list);
880 
881 	/*
882 	 * Call into late init to do initializations that require
883 	 * both sr driver and sr class driver to be initiallized.
884 	 */
885 	if (sr_class) {
886 		ret = sr_late_init(sr_info);
887 		if (ret) {
888 			pr_warn("%s: Error in SR late init\n", __func__);
889 			goto err_list_del;
890 		}
891 	}
892 
893 	dev_info(&pdev->dev, "%s: SmartReflex driver initialized\n", __func__);
894 	if (!sr_dbg_dir)
895 		sr_dbg_dir = debugfs_create_dir("smartreflex", NULL);
896 
897 	sr_info->dbg_dir = debugfs_create_dir(sr_info->name, sr_dbg_dir);
898 
899 	debugfs_create_file("autocomp", S_IRUGO | S_IWUSR, sr_info->dbg_dir,
900 			    sr_info, &pm_sr_fops);
901 	debugfs_create_x32("errweight", S_IRUGO, sr_info->dbg_dir,
902 			   &sr_info->err_weight);
903 	debugfs_create_x32("errmaxlimit", S_IRUGO, sr_info->dbg_dir,
904 			   &sr_info->err_maxlimit);
905 
906 	nvalue_dir = debugfs_create_dir("nvalue", sr_info->dbg_dir);
907 
908 	if (sr_info->nvalue_count == 0 || !sr_info->nvalue_table) {
909 		dev_warn(&pdev->dev, "%s: %s: No Voltage table for the corresponding vdd. Cannot create debugfs entries for n-values\n",
910 			 __func__, sr_info->name);
911 
912 		ret = -ENODATA;
913 		goto err_debugfs;
914 	}
915 
916 	for (i = 0; i < sr_info->nvalue_count; i++) {
917 		char name[NVALUE_NAME_LEN + 1];
918 
919 		snprintf(name, sizeof(name), "volt_%lu",
920 				sr_info->nvalue_table[i].volt_nominal);
921 		debugfs_create_x32(name, S_IRUGO | S_IWUSR, nvalue_dir,
922 				   &(sr_info->nvalue_table[i].nvalue));
923 		snprintf(name, sizeof(name), "errminlimit_%lu",
924 			 sr_info->nvalue_table[i].volt_nominal);
925 		debugfs_create_x32(name, S_IRUGO | S_IWUSR, nvalue_dir,
926 				   &(sr_info->nvalue_table[i].errminlimit));
927 
928 	}
929 
930 	return 0;
931 
932 err_debugfs:
933 	debugfs_remove_recursive(sr_info->dbg_dir);
934 err_list_del:
935 	pm_runtime_disable(&pdev->dev);
936 	list_del(&sr_info->node);
937 	clk_unprepare(sr_info->fck);
938 
939 	return ret;
940 }
941 
942 static int omap_sr_remove(struct platform_device *pdev)
943 {
944 	struct omap_sr_data *pdata = pdev->dev.platform_data;
945 	struct device *dev = &pdev->dev;
946 	struct omap_sr *sr_info;
947 
948 	if (!pdata) {
949 		dev_err(&pdev->dev, "%s: platform data missing\n", __func__);
950 		return -EINVAL;
951 	}
952 
953 	sr_info = _sr_lookup(pdata->voltdm);
954 	if (IS_ERR(sr_info)) {
955 		dev_warn(&pdev->dev, "%s: omap_sr struct not found\n",
956 			__func__);
957 		return PTR_ERR(sr_info);
958 	}
959 
960 	if (sr_info->autocomp_active)
961 		sr_stop_vddautocomp(sr_info);
962 	debugfs_remove_recursive(sr_info->dbg_dir);
963 
964 	pm_runtime_disable(dev);
965 	clk_unprepare(sr_info->fck);
966 	list_del(&sr_info->node);
967 	return 0;
968 }
969 
970 static void omap_sr_shutdown(struct platform_device *pdev)
971 {
972 	struct omap_sr_data *pdata = pdev->dev.platform_data;
973 	struct omap_sr *sr_info;
974 
975 	if (!pdata) {
976 		dev_err(&pdev->dev, "%s: platform data missing\n", __func__);
977 		return;
978 	}
979 
980 	sr_info = _sr_lookup(pdata->voltdm);
981 	if (IS_ERR(sr_info)) {
982 		dev_warn(&pdev->dev, "%s: omap_sr struct not found\n",
983 			__func__);
984 		return;
985 	}
986 
987 	if (sr_info->autocomp_active)
988 		sr_stop_vddautocomp(sr_info);
989 
990 	return;
991 }
992 
993 static const struct of_device_id omap_sr_match[] = {
994 	{ .compatible = "ti,omap3-smartreflex-core", },
995 	{ .compatible = "ti,omap3-smartreflex-mpu-iva", },
996 	{ .compatible = "ti,omap4-smartreflex-core", },
997 	{ .compatible = "ti,omap4-smartreflex-mpu", },
998 	{ .compatible = "ti,omap4-smartreflex-iva", },
999 	{  },
1000 };
1001 MODULE_DEVICE_TABLE(of, omap_sr_match);
1002 
1003 static struct platform_driver smartreflex_driver = {
1004 	.probe		= omap_sr_probe,
1005 	.remove         = omap_sr_remove,
1006 	.shutdown	= omap_sr_shutdown,
1007 	.driver		= {
1008 		.name	= DRIVER_NAME,
1009 		.of_match_table	= omap_sr_match,
1010 	},
1011 };
1012 
1013 static int __init sr_init(void)
1014 {
1015 	int ret = 0;
1016 
1017 	ret = platform_driver_register(&smartreflex_driver);
1018 	if (ret) {
1019 		pr_err("%s: platform driver register failed for SR\n",
1020 		       __func__);
1021 		return ret;
1022 	}
1023 
1024 	return 0;
1025 }
1026 late_initcall(sr_init);
1027 
1028 static void __exit sr_exit(void)
1029 {
1030 	platform_driver_unregister(&smartreflex_driver);
1031 }
1032 module_exit(sr_exit);
1033 
1034 MODULE_DESCRIPTION("OMAP Smartreflex Driver");
1035 MODULE_LICENSE("GPL");
1036 MODULE_ALIAS("platform:" DRIVER_NAME);
1037 MODULE_AUTHOR("Texas Instruments Inc");
1038