1 /*
2  * Texas Instruments SoC Adaptive Body Bias(ABB) Regulator
3  *
4  * Copyright (C) 2011 Texas Instruments, Inc.
5  * Mike Turquette <mturquette@ti.com>
6  *
7  * Copyright (C) 2012-2013 Texas Instruments, Inc.
8  * Andrii Tseglytskyi <andrii.tseglytskyi@ti.com>
9  * Nishanth Menon <nm@ti.com>
10  *
11  * This program is free software; you can redistribute it and/or modify
12  * it under the terms of the GNU General Public License version 2 as
13  * published by the Free Software Foundation.
14  *
15  * This program is distributed "as is" WITHOUT ANY WARRANTY of any
16  * kind, whether express or implied; without even the implied warranty
17  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18  * GNU General Public License for more details.
19  */
20 #include <linux/clk.h>
21 #include <linux/delay.h>
22 #include <linux/err.h>
23 #include <linux/io.h>
24 #include <linux/module.h>
25 #include <linux/of_device.h>
26 #include <linux/of.h>
27 #include <linux/platform_device.h>
28 #include <linux/regulator/driver.h>
29 #include <linux/regulator/machine.h>
30 #include <linux/regulator/of_regulator.h>
31 
32 /*
33  * ABB LDO operating states:
34  * NOMINAL_OPP:	bypasses the ABB LDO
35  * FAST_OPP:	sets ABB LDO to Forward Body-Bias
36  * SLOW_OPP:	sets ABB LDO to Reverse Body-Bias
37  */
38 #define TI_ABB_NOMINAL_OPP	0
39 #define TI_ABB_FAST_OPP		1
40 #define TI_ABB_SLOW_OPP		3
41 
42 /**
43  * struct ti_abb_info - ABB information per voltage setting
44  * @opp_sel:	one of TI_ABB macro
45  * @vset:	(optional) vset value that LDOVBB needs to be overriden with.
46  *
47  * Array of per voltage entries organized in the same order as regulator_desc's
48  * volt_table list. (selector is used to index from this array)
49  */
50 struct ti_abb_info {
51 	u32 opp_sel;
52 	u32 vset;
53 };
54 
55 /**
56  * struct ti_abb_reg - Register description for ABB block
57  * @setup_reg:			setup register offset from base
58  * @control_reg:		control register offset from base
59  * @sr2_wtcnt_value_mask:	setup register- sr2_wtcnt_value mask
60  * @fbb_sel_mask:		setup register- FBB sel mask
61  * @rbb_sel_mask:		setup register- RBB sel mask
62  * @sr2_en_mask:		setup register- enable mask
63  * @opp_change_mask:		control register - mask to trigger LDOVBB change
64  * @opp_sel_mask:		control register - mask for mode to operate
65  */
66 struct ti_abb_reg {
67 	u32 setup_reg;
68 	u32 control_reg;
69 
70 	/* Setup register fields */
71 	u32 sr2_wtcnt_value_mask;
72 	u32 fbb_sel_mask;
73 	u32 rbb_sel_mask;
74 	u32 sr2_en_mask;
75 
76 	/* Control register fields */
77 	u32 opp_change_mask;
78 	u32 opp_sel_mask;
79 };
80 
81 /**
82  * struct ti_abb - ABB instance data
83  * @rdesc:			regulator descriptor
84  * @clk:			clock(usually sysclk) supplying ABB block
85  * @base:			base address of ABB block
86  * @int_base:			interrupt register base address
87  * @efuse_base:			(optional) efuse base address for ABB modes
88  * @ldo_base:			(optional) LDOVBB vset override base address
89  * @regs:			pointer to struct ti_abb_reg for ABB block
90  * @txdone_mask:		mask on int_base for tranxdone interrupt
91  * @ldovbb_override_mask:	mask to ldo_base for overriding default LDO VBB
92  *				vset with value from efuse
93  * @ldovbb_vset_mask:		mask to ldo_base for providing the VSET override
94  * @info:			array to per voltage ABB configuration
95  * @current_info_idx:		current index to info
96  * @settling_time:		SoC specific settling time for LDO VBB
97  */
98 struct ti_abb {
99 	struct regulator_desc rdesc;
100 	struct clk *clk;
101 	void __iomem *base;
102 	void __iomem *int_base;
103 	void __iomem *efuse_base;
104 	void __iomem *ldo_base;
105 
106 	const struct ti_abb_reg *regs;
107 	u32 txdone_mask;
108 	u32 ldovbb_override_mask;
109 	u32 ldovbb_vset_mask;
110 
111 	struct ti_abb_info *info;
112 	int current_info_idx;
113 
114 	u32 settling_time;
115 };
116 
117 /**
118  * ti_abb_rmw() - handy wrapper to set specific register bits
119  * @mask:	mask for register field
120  * @value:	value shifted to mask location and written
121  * @offset:	offset of register
122  * @base:	base address
123  *
124  * Return: final register value (may be unused)
125  */
126 static inline u32 ti_abb_rmw(u32 mask, u32 value, u32 offset,
127 			     void __iomem *base)
128 {
129 	u32 val;
130 
131 	val = readl(base + offset);
132 	val &= ~mask;
133 	val |= (value << __ffs(mask)) & mask;
134 	writel(val, base + offset);
135 
136 	return val;
137 }
138 
139 /**
140  * ti_abb_check_txdone() - handy wrapper to check ABB tranxdone status
141  * @abb:	pointer to the abb instance
142  *
143  * Return: true or false
144  */
145 static inline bool ti_abb_check_txdone(const struct ti_abb *abb)
146 {
147 	return !!(readl(abb->int_base) & abb->txdone_mask);
148 }
149 
150 /**
151  * ti_abb_clear_txdone() - handy wrapper to clear ABB tranxdone status
152  * @abb:	pointer to the abb instance
153  */
154 static inline void ti_abb_clear_txdone(const struct ti_abb *abb)
155 {
156 	writel(abb->txdone_mask, abb->int_base);
157 };
158 
159 /**
160  * ti_abb_wait_tranx() - waits for ABB tranxdone event
161  * @dev:	device
162  * @abb:	pointer to the abb instance
163  *
164  * Return: 0 on success or -ETIMEDOUT if the event is not cleared on time.
165  */
166 static int ti_abb_wait_txdone(struct device *dev, struct ti_abb *abb)
167 {
168 	int timeout = 0;
169 	bool status;
170 
171 	while (timeout++ <= abb->settling_time) {
172 		status = ti_abb_check_txdone(abb);
173 		if (status)
174 			break;
175 
176 		udelay(1);
177 	}
178 
179 	if (timeout > abb->settling_time) {
180 		dev_warn_ratelimited(dev,
181 				     "%s:TRANXDONE timeout(%duS) int=0x%08x\n",
182 				     __func__, timeout, readl(abb->int_base));
183 		return -ETIMEDOUT;
184 	}
185 
186 	return 0;
187 }
188 
189 /**
190  * ti_abb_clear_all_txdone() - clears ABB tranxdone event
191  * @dev:	device
192  * @abb:	pointer to the abb instance
193  *
194  * Return: 0 on success or -ETIMEDOUT if the event is not cleared on time.
195  */
196 static int ti_abb_clear_all_txdone(struct device *dev, const struct ti_abb *abb)
197 {
198 	int timeout = 0;
199 	bool status;
200 
201 	while (timeout++ <= abb->settling_time) {
202 		ti_abb_clear_txdone(abb);
203 
204 		status = ti_abb_check_txdone(abb);
205 		if (!status)
206 			break;
207 
208 		udelay(1);
209 	}
210 
211 	if (timeout > abb->settling_time) {
212 		dev_warn_ratelimited(dev,
213 				     "%s:TRANXDONE timeout(%duS) int=0x%08x\n",
214 				     __func__, timeout, readl(abb->int_base));
215 		return -ETIMEDOUT;
216 	}
217 
218 	return 0;
219 }
220 
221 /**
222  * ti_abb_program_ldovbb() - program LDOVBB register for override value
223  * @dev:	device
224  * @abb:	pointer to the abb instance
225  * @info:	ABB info to program
226  */
227 static void ti_abb_program_ldovbb(struct device *dev, const struct ti_abb *abb,
228 				  struct ti_abb_info *info)
229 {
230 	u32 val;
231 
232 	val = readl(abb->ldo_base);
233 	/* clear up previous values */
234 	val &= ~(abb->ldovbb_override_mask | abb->ldovbb_vset_mask);
235 
236 	switch (info->opp_sel) {
237 	case TI_ABB_SLOW_OPP:
238 	case TI_ABB_FAST_OPP:
239 		val |= abb->ldovbb_override_mask;
240 		val |= info->vset << __ffs(abb->ldovbb_vset_mask);
241 		break;
242 	}
243 
244 	writel(val, abb->ldo_base);
245 }
246 
247 /**
248  * ti_abb_set_opp() - Setup ABB and LDO VBB for required bias
249  * @rdev:	regulator device
250  * @abb:	pointer to the abb instance
251  * @info:	ABB info to program
252  *
253  * Return: 0 on success or appropriate error value when fails
254  */
255 static int ti_abb_set_opp(struct regulator_dev *rdev, struct ti_abb *abb,
256 			  struct ti_abb_info *info)
257 {
258 	const struct ti_abb_reg *regs = abb->regs;
259 	struct device *dev = &rdev->dev;
260 	int ret;
261 
262 	ret = ti_abb_clear_all_txdone(dev, abb);
263 	if (ret)
264 		goto out;
265 
266 	ti_abb_rmw(regs->fbb_sel_mask | regs->rbb_sel_mask, 0, regs->setup_reg,
267 		   abb->base);
268 
269 	switch (info->opp_sel) {
270 	case TI_ABB_SLOW_OPP:
271 		ti_abb_rmw(regs->rbb_sel_mask, 1, regs->setup_reg, abb->base);
272 		break;
273 	case TI_ABB_FAST_OPP:
274 		ti_abb_rmw(regs->fbb_sel_mask, 1, regs->setup_reg, abb->base);
275 		break;
276 	}
277 
278 	/* program next state of ABB ldo */
279 	ti_abb_rmw(regs->opp_sel_mask, info->opp_sel, regs->control_reg,
280 		   abb->base);
281 
282 	/*
283 	 * program LDO VBB vset override if needed for !bypass mode
284 	 * XXX: Do not switch sequence - for !bypass, LDO override reset *must*
285 	 * be performed *before* switch to bias mode else VBB glitches.
286 	 */
287 	if (abb->ldo_base && info->opp_sel != TI_ABB_NOMINAL_OPP)
288 		ti_abb_program_ldovbb(dev, abb, info);
289 
290 	/* Initiate ABB ldo change */
291 	ti_abb_rmw(regs->opp_change_mask, 1, regs->control_reg, abb->base);
292 
293 	/* Wait for ABB LDO to complete transition to new Bias setting */
294 	ret = ti_abb_wait_txdone(dev, abb);
295 	if (ret)
296 		goto out;
297 
298 	ret = ti_abb_clear_all_txdone(dev, abb);
299 	if (ret)
300 		goto out;
301 
302 	/*
303 	 * Reset LDO VBB vset override bypass mode
304 	 * XXX: Do not switch sequence - for bypass, LDO override reset *must*
305 	 * be performed *after* switch to bypass else VBB glitches.
306 	 */
307 	if (abb->ldo_base && info->opp_sel == TI_ABB_NOMINAL_OPP)
308 		ti_abb_program_ldovbb(dev, abb, info);
309 
310 out:
311 	return ret;
312 }
313 
314 /**
315  * ti_abb_set_voltage_sel() - regulator accessor function to set ABB LDO
316  * @rdev:	regulator device
317  * @sel:	selector to index into required ABB LDO settings (maps to
318  *		regulator descriptor's volt_table)
319  *
320  * Return: 0 on success or appropriate error value when fails
321  */
322 static int ti_abb_set_voltage_sel(struct regulator_dev *rdev, unsigned sel)
323 {
324 	const struct regulator_desc *desc = rdev->desc;
325 	struct ti_abb *abb = rdev_get_drvdata(rdev);
326 	struct device *dev = &rdev->dev;
327 	struct ti_abb_info *info, *oinfo;
328 	int ret = 0;
329 
330 	if (!abb) {
331 		dev_err_ratelimited(dev, "%s: No regulator drvdata\n",
332 				    __func__);
333 		return -ENODEV;
334 	}
335 
336 	if (!desc->n_voltages || !abb->info) {
337 		dev_err_ratelimited(dev,
338 				    "%s: No valid voltage table entries?\n",
339 				    __func__);
340 		return -EINVAL;
341 	}
342 
343 	if (sel >= desc->n_voltages) {
344 		dev_err(dev, "%s: sel idx(%d) >= n_voltages(%d)\n", __func__,
345 			sel, desc->n_voltages);
346 		return -EINVAL;
347 	}
348 
349 	/* If we are in the same index as we were, nothing to do here! */
350 	if (sel == abb->current_info_idx) {
351 		dev_dbg(dev, "%s: Already at sel=%d\n", __func__, sel);
352 		return ret;
353 	}
354 
355 	/* If data is exactly the same, then just update index, no change */
356 	info = &abb->info[sel];
357 	oinfo = &abb->info[abb->current_info_idx];
358 	if (!memcmp(info, oinfo, sizeof(*info))) {
359 		dev_dbg(dev, "%s: Same data new idx=%d, old idx=%d\n", __func__,
360 			sel, abb->current_info_idx);
361 		goto out;
362 	}
363 
364 	ret = ti_abb_set_opp(rdev, abb, info);
365 
366 out:
367 	if (!ret)
368 		abb->current_info_idx = sel;
369 	else
370 		dev_err_ratelimited(dev,
371 				    "%s: Volt[%d] idx[%d] mode[%d] Fail(%d)\n",
372 				    __func__, desc->volt_table[sel], sel,
373 				    info->opp_sel, ret);
374 	return ret;
375 }
376 
377 /**
378  * ti_abb_get_voltage_sel() - Regulator accessor to get current ABB LDO setting
379  * @rdev:	regulator device
380  *
381  * Return: 0 on success or appropriate error value when fails
382  */
383 static int ti_abb_get_voltage_sel(struct regulator_dev *rdev)
384 {
385 	const struct regulator_desc *desc = rdev->desc;
386 	struct ti_abb *abb = rdev_get_drvdata(rdev);
387 	struct device *dev = &rdev->dev;
388 
389 	if (!abb) {
390 		dev_err_ratelimited(dev, "%s: No regulator drvdata\n",
391 				    __func__);
392 		return -ENODEV;
393 	}
394 
395 	if (!desc->n_voltages || !abb->info) {
396 		dev_err_ratelimited(dev,
397 				    "%s: No valid voltage table entries?\n",
398 				    __func__);
399 		return -EINVAL;
400 	}
401 
402 	if (abb->current_info_idx >= (int)desc->n_voltages) {
403 		dev_err(dev, "%s: Corrupted data? idx(%d) >= n_voltages(%d)\n",
404 			__func__, abb->current_info_idx, desc->n_voltages);
405 		return -EINVAL;
406 	}
407 
408 	return abb->current_info_idx;
409 }
410 
411 /**
412  * ti_abb_init_timings() - setup ABB clock timing for the current platform
413  * @dev:	device
414  * @abb:	pointer to the abb instance
415  *
416  * Return: 0 if timing is updated, else returns error result.
417  */
418 static int ti_abb_init_timings(struct device *dev, struct ti_abb *abb)
419 {
420 	u32 clock_cycles;
421 	u32 clk_rate, sr2_wt_cnt_val, cycle_rate;
422 	const struct ti_abb_reg *regs = abb->regs;
423 	int ret;
424 	char *pname = "ti,settling-time";
425 
426 	/* read device tree properties */
427 	ret = of_property_read_u32(dev->of_node, pname, &abb->settling_time);
428 	if (ret) {
429 		dev_err(dev, "Unable to get property '%s'(%d)\n", pname, ret);
430 		return ret;
431 	}
432 
433 	/* ABB LDO cannot be settle in 0 time */
434 	if (!abb->settling_time) {
435 		dev_err(dev, "Invalid property:'%s' set as 0!\n", pname);
436 		return -EINVAL;
437 	}
438 
439 	pname = "ti,clock-cycles";
440 	ret = of_property_read_u32(dev->of_node, pname, &clock_cycles);
441 	if (ret) {
442 		dev_err(dev, "Unable to get property '%s'(%d)\n", pname, ret);
443 		return ret;
444 	}
445 	/* ABB LDO cannot be settle in 0 clock cycles */
446 	if (!clock_cycles) {
447 		dev_err(dev, "Invalid property:'%s' set as 0!\n", pname);
448 		return -EINVAL;
449 	}
450 
451 	abb->clk = devm_clk_get(dev, NULL);
452 	if (IS_ERR(abb->clk)) {
453 		ret = PTR_ERR(abb->clk);
454 		dev_err(dev, "%s: Unable to get clk(%d)\n", __func__, ret);
455 		return ret;
456 	}
457 
458 	/*
459 	 * SR2_WTCNT_VALUE is the settling time for the ABB ldo after a
460 	 * transition and must be programmed with the correct time at boot.
461 	 * The value programmed into the register is the number of SYS_CLK
462 	 * clock cycles that match a given wall time profiled for the ldo.
463 	 * This value depends on:
464 	 * settling time of ldo in micro-seconds (varies per OMAP family)
465 	 * # of clock cycles per SYS_CLK period (varies per OMAP family)
466 	 * the SYS_CLK frequency in MHz (varies per board)
467 	 * The formula is:
468 	 *
469 	 *                      ldo settling time (in micro-seconds)
470 	 * SR2_WTCNT_VALUE = ------------------------------------------
471 	 *                   (# system clock cycles) * (sys_clk period)
472 	 *
473 	 * Put another way:
474 	 *
475 	 * SR2_WTCNT_VALUE = settling time / (# SYS_CLK cycles / SYS_CLK rate))
476 	 *
477 	 * To avoid dividing by zero multiply both "# clock cycles" and
478 	 * "settling time" by 10 such that the final result is the one we want.
479 	 */
480 
481 	/* Convert SYS_CLK rate to MHz & prevent divide by zero */
482 	clk_rate = DIV_ROUND_CLOSEST(clk_get_rate(abb->clk), 1000000);
483 
484 	/* Calculate cycle rate */
485 	cycle_rate = DIV_ROUND_CLOSEST(clock_cycles * 10, clk_rate);
486 
487 	/* Calulate SR2_WTCNT_VALUE */
488 	sr2_wt_cnt_val = DIV_ROUND_CLOSEST(abb->settling_time * 10, cycle_rate);
489 
490 	dev_dbg(dev, "%s: Clk_rate=%ld, sr2_cnt=0x%08x\n", __func__,
491 		clk_get_rate(abb->clk), sr2_wt_cnt_val);
492 
493 	ti_abb_rmw(regs->sr2_wtcnt_value_mask, sr2_wt_cnt_val, regs->setup_reg,
494 		   abb->base);
495 
496 	return 0;
497 }
498 
499 /**
500  * ti_abb_init_table() - Initialize ABB table from device tree
501  * @dev:	device
502  * @abb:	pointer to the abb instance
503  * @rinit_data:	regulator initdata
504  *
505  * Return: 0 on success or appropriate error value when fails
506  */
507 static int ti_abb_init_table(struct device *dev, struct ti_abb *abb,
508 			     struct regulator_init_data *rinit_data)
509 {
510 	struct ti_abb_info *info;
511 	const struct property *prop;
512 	const __be32 *abb_info;
513 	const u32 num_values = 6;
514 	char *pname = "ti,abb_info";
515 	u32 num_entries, i;
516 	unsigned int *volt_table;
517 	int min_uV = INT_MAX, max_uV = 0;
518 	struct regulation_constraints *c = &rinit_data->constraints;
519 
520 	prop = of_find_property(dev->of_node, pname, NULL);
521 	if (!prop) {
522 		dev_err(dev, "No '%s' property?\n", pname);
523 		return -ENODEV;
524 	}
525 
526 	if (!prop->value) {
527 		dev_err(dev, "Empty '%s' property?\n", pname);
528 		return -ENODATA;
529 	}
530 
531 	/*
532 	 * Each abb_info is a set of n-tuple, where n is num_values, consisting
533 	 * of voltage and a set of detection logic for ABB information for that
534 	 * voltage to apply.
535 	 */
536 	num_entries = prop->length / sizeof(u32);
537 	if (!num_entries || (num_entries % num_values)) {
538 		dev_err(dev, "All '%s' list entries need %d vals\n", pname,
539 			num_values);
540 		return -EINVAL;
541 	}
542 	num_entries /= num_values;
543 
544 	info = devm_kzalloc(dev, sizeof(*info) * num_entries, GFP_KERNEL);
545 	if (!info) {
546 		dev_err(dev, "Can't allocate info table for '%s' property\n",
547 			pname);
548 		return -ENOMEM;
549 	}
550 	abb->info = info;
551 
552 	volt_table = devm_kzalloc(dev, sizeof(unsigned int) * num_entries,
553 				  GFP_KERNEL);
554 	if (!volt_table) {
555 		dev_err(dev, "Can't allocate voltage table for '%s' property\n",
556 			pname);
557 		return -ENOMEM;
558 	}
559 
560 	abb->rdesc.n_voltages = num_entries;
561 	abb->rdesc.volt_table = volt_table;
562 	/* We do not know where the OPP voltage is at the moment */
563 	abb->current_info_idx = -EINVAL;
564 
565 	abb_info = prop->value;
566 	for (i = 0; i < num_entries; i++, info++, volt_table++) {
567 		u32 efuse_offset, rbb_mask, fbb_mask, vset_mask;
568 		u32 efuse_val;
569 
570 		/* NOTE: num_values should equal to entries picked up here */
571 		*volt_table = be32_to_cpup(abb_info++);
572 		info->opp_sel = be32_to_cpup(abb_info++);
573 		efuse_offset = be32_to_cpup(abb_info++);
574 		rbb_mask = be32_to_cpup(abb_info++);
575 		fbb_mask = be32_to_cpup(abb_info++);
576 		vset_mask = be32_to_cpup(abb_info++);
577 
578 		dev_dbg(dev,
579 			"[%d]v=%d ABB=%d ef=0x%x rbb=0x%x fbb=0x%x vset=0x%x\n",
580 			i, *volt_table, info->opp_sel, efuse_offset, rbb_mask,
581 			fbb_mask, vset_mask);
582 
583 		/* Find min/max for voltage set */
584 		if (min_uV > *volt_table)
585 			min_uV = *volt_table;
586 		if (max_uV < *volt_table)
587 			max_uV = *volt_table;
588 
589 		if (!abb->efuse_base) {
590 			/* Ignore invalid data, but warn to help cleanup */
591 			if (efuse_offset || rbb_mask || fbb_mask || vset_mask)
592 				dev_err(dev, "prop '%s': v=%d,bad efuse/mask\n",
593 					pname, *volt_table);
594 			goto check_abb;
595 		}
596 
597 		efuse_val = readl(abb->efuse_base + efuse_offset);
598 
599 		/* Use ABB recommendation from Efuse */
600 		if (efuse_val & rbb_mask)
601 			info->opp_sel = TI_ABB_SLOW_OPP;
602 		else if (efuse_val & fbb_mask)
603 			info->opp_sel = TI_ABB_FAST_OPP;
604 		else if (rbb_mask || fbb_mask)
605 			info->opp_sel = TI_ABB_NOMINAL_OPP;
606 
607 		dev_dbg(dev,
608 			"[%d]v=%d efusev=0x%x final ABB=%d\n",
609 			i, *volt_table, efuse_val, info->opp_sel);
610 
611 		/* Use recommended Vset bits from Efuse */
612 		if (!abb->ldo_base) {
613 			if (vset_mask)
614 				dev_err(dev, "prop'%s':v=%d vst=%x LDO base?\n",
615 					pname, *volt_table, vset_mask);
616 			continue;
617 		}
618 		info->vset = efuse_val & vset_mask >> __ffs(vset_mask);
619 		dev_dbg(dev, "[%d]v=%d vset=%x\n", i, *volt_table, info->vset);
620 check_abb:
621 		switch (info->opp_sel) {
622 		case TI_ABB_NOMINAL_OPP:
623 		case TI_ABB_FAST_OPP:
624 		case TI_ABB_SLOW_OPP:
625 			/* Valid values */
626 			break;
627 		default:
628 			dev_err(dev, "%s:[%d]v=%d, ABB=%d is invalid! Abort!\n",
629 				__func__, i, *volt_table, info->opp_sel);
630 			return -EINVAL;
631 		}
632 	}
633 
634 	/* Setup the min/max voltage constraints from the supported list */
635 	c->min_uV = min_uV;
636 	c->max_uV = max_uV;
637 
638 	return 0;
639 }
640 
641 static struct regulator_ops ti_abb_reg_ops = {
642 	.list_voltage = regulator_list_voltage_table,
643 
644 	.set_voltage_sel = ti_abb_set_voltage_sel,
645 	.get_voltage_sel = ti_abb_get_voltage_sel,
646 };
647 
648 /* Default ABB block offsets, IF this changes in future, create new one */
649 static const struct ti_abb_reg abb_regs_v1 = {
650 	/* WARNING: registers are wrongly documented in TRM */
651 	.setup_reg		= 0x04,
652 	.control_reg		= 0x00,
653 
654 	.sr2_wtcnt_value_mask	= (0xff << 8),
655 	.fbb_sel_mask		= (0x01 << 2),
656 	.rbb_sel_mask		= (0x01 << 1),
657 	.sr2_en_mask		= (0x01 << 0),
658 
659 	.opp_change_mask	= (0x01 << 2),
660 	.opp_sel_mask		= (0x03 << 0),
661 };
662 
663 static const struct ti_abb_reg abb_regs_v2 = {
664 	.setup_reg		= 0x00,
665 	.control_reg		= 0x04,
666 
667 	.sr2_wtcnt_value_mask	= (0xff << 8),
668 	.fbb_sel_mask		= (0x01 << 2),
669 	.rbb_sel_mask		= (0x01 << 1),
670 	.sr2_en_mask		= (0x01 << 0),
671 
672 	.opp_change_mask	= (0x01 << 2),
673 	.opp_sel_mask		= (0x03 << 0),
674 };
675 
676 static const struct of_device_id ti_abb_of_match[] = {
677 	{.compatible = "ti,abb-v1", .data = &abb_regs_v1},
678 	{.compatible = "ti,abb-v2", .data = &abb_regs_v2},
679 	{ },
680 };
681 
682 MODULE_DEVICE_TABLE(of, ti_abb_of_match);
683 
684 /**
685  * ti_abb_probe() - Initialize an ABB ldo instance
686  * @pdev: ABB platform device
687  *
688  * Initializes an individual ABB LDO for required Body-Bias. ABB is used to
689  * addional bias supply to SoC modules for power savings or mandatory stability
690  * configuration at certain Operating Performance Points(OPPs).
691  *
692  * Return: 0 on success or appropriate error value when fails
693  */
694 static int ti_abb_probe(struct platform_device *pdev)
695 {
696 	struct device *dev = &pdev->dev;
697 	const struct of_device_id *match;
698 	struct resource *res;
699 	struct ti_abb *abb;
700 	struct regulator_init_data *initdata = NULL;
701 	struct regulator_dev *rdev = NULL;
702 	struct regulator_desc *desc;
703 	struct regulation_constraints *c;
704 	struct regulator_config config = { };
705 	char *pname;
706 	int ret = 0;
707 
708 	match = of_match_device(ti_abb_of_match, dev);
709 	if (!match) {
710 		/* We do not expect this to happen */
711 		ret = -ENODEV;
712 		dev_err(dev, "%s: Unable to match device\n", __func__);
713 		goto err;
714 	}
715 	if (!match->data) {
716 		ret = -EINVAL;
717 		dev_err(dev, "%s: Bad data in match\n", __func__);
718 		goto err;
719 	}
720 
721 	abb = devm_kzalloc(dev, sizeof(struct ti_abb), GFP_KERNEL);
722 	if (!abb) {
723 		dev_err(dev, "%s: Unable to allocate ABB struct\n", __func__);
724 		ret = -ENOMEM;
725 		goto err;
726 	}
727 	abb->regs = match->data;
728 
729 	/* Map ABB resources */
730 	pname = "base-address";
731 	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, pname);
732 	abb->base = devm_ioremap_resource(dev, res);
733 	if (IS_ERR(abb->base)) {
734 		ret = PTR_ERR(abb->base);
735 		goto err;
736 	}
737 
738 	pname = "int-address";
739 	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, pname);
740 	if (!res) {
741 		dev_err(dev, "Missing '%s' IO resource\n", pname);
742 		ret = -ENODEV;
743 		goto err;
744 	}
745 	/*
746 	 * We may have shared interrupt register offsets which are
747 	 * write-1-to-clear between domains ensuring exclusivity.
748 	 */
749 	abb->int_base = devm_ioremap_nocache(dev, res->start,
750 					     resource_size(res));
751 	if (!abb->int_base) {
752 		dev_err(dev, "Unable to map '%s'\n", pname);
753 		ret = -ENOMEM;
754 		goto err;
755 	}
756 
757 	/* Map Optional resources */
758 	pname = "efuse-address";
759 	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, pname);
760 	if (!res) {
761 		dev_dbg(dev, "Missing '%s' IO resource\n", pname);
762 		ret = -ENODEV;
763 		goto skip_opt;
764 	}
765 
766 	/*
767 	 * We may have shared efuse register offsets which are read-only
768 	 * between domains
769 	 */
770 	abb->efuse_base = devm_ioremap_nocache(dev, res->start,
771 					       resource_size(res));
772 	if (!abb->efuse_base) {
773 		dev_err(dev, "Unable to map '%s'\n", pname);
774 		ret = -ENOMEM;
775 		goto err;
776 	}
777 
778 	pname = "ldo-address";
779 	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, pname);
780 	abb->ldo_base = devm_ioremap_resource(dev, res);
781 	if (IS_ERR(abb->ldo_base)) {
782 		ret = PTR_ERR(abb->ldo_base);
783 		goto err;
784 	}
785 
786 	/* IF ldo_base is set, the following are mandatory */
787 	pname = "ti,ldovbb-override-mask";
788 	ret =
789 	    of_property_read_u32(pdev->dev.of_node, pname,
790 				 &abb->ldovbb_override_mask);
791 	if (ret) {
792 		dev_err(dev, "Missing '%s' (%d)\n", pname, ret);
793 		goto err;
794 	}
795 	if (!abb->ldovbb_override_mask) {
796 		dev_err(dev, "Invalid property:'%s' set as 0!\n", pname);
797 		ret = -EINVAL;
798 		goto err;
799 	}
800 
801 	pname = "ti,ldovbb-vset-mask";
802 	ret =
803 	    of_property_read_u32(pdev->dev.of_node, pname,
804 				 &abb->ldovbb_vset_mask);
805 	if (ret) {
806 		dev_err(dev, "Missing '%s' (%d)\n", pname, ret);
807 		goto err;
808 	}
809 	if (!abb->ldovbb_vset_mask) {
810 		dev_err(dev, "Invalid property:'%s' set as 0!\n", pname);
811 		ret = -EINVAL;
812 		goto err;
813 	}
814 
815 skip_opt:
816 	pname = "ti,tranxdone-status-mask";
817 	ret =
818 	    of_property_read_u32(pdev->dev.of_node, pname,
819 				 &abb->txdone_mask);
820 	if (ret) {
821 		dev_err(dev, "Missing '%s' (%d)\n", pname, ret);
822 		goto err;
823 	}
824 	if (!abb->txdone_mask) {
825 		dev_err(dev, "Invalid property:'%s' set as 0!\n", pname);
826 		ret = -EINVAL;
827 		goto err;
828 	}
829 
830 	initdata = of_get_regulator_init_data(dev, pdev->dev.of_node);
831 	if (!initdata) {
832 		ret = -ENOMEM;
833 		dev_err(dev, "%s: Unable to alloc regulator init data\n",
834 			__func__);
835 		goto err;
836 	}
837 
838 	/* init ABB opp_sel table */
839 	ret = ti_abb_init_table(dev, abb, initdata);
840 	if (ret)
841 		goto err;
842 
843 	/* init ABB timing */
844 	ret = ti_abb_init_timings(dev, abb);
845 	if (ret)
846 		goto err;
847 
848 	desc = &abb->rdesc;
849 	desc->name = dev_name(dev);
850 	desc->owner = THIS_MODULE;
851 	desc->type = REGULATOR_VOLTAGE;
852 	desc->ops = &ti_abb_reg_ops;
853 
854 	c = &initdata->constraints;
855 	if (desc->n_voltages > 1)
856 		c->valid_ops_mask |= REGULATOR_CHANGE_VOLTAGE;
857 	c->always_on = true;
858 
859 	config.dev = dev;
860 	config.init_data = initdata;
861 	config.driver_data = abb;
862 	config.of_node = pdev->dev.of_node;
863 
864 	rdev = regulator_register(desc, &config);
865 	if (IS_ERR(rdev)) {
866 		ret = PTR_ERR(rdev);
867 		dev_err(dev, "%s: failed to register regulator(%d)\n",
868 			__func__, ret);
869 		goto err;
870 	}
871 	platform_set_drvdata(pdev, rdev);
872 
873 	/* Enable the ldo if not already done by bootloader */
874 	ti_abb_rmw(abb->regs->sr2_en_mask, 1, abb->regs->setup_reg, abb->base);
875 
876 	return 0;
877 
878 err:
879 	dev_err(dev, "%s: Failed to initialize(%d)\n", __func__, ret);
880 	return ret;
881 }
882 
883 /**
884  * ti_abb_remove() - cleanups
885  * @pdev: ABB platform device
886  *
887  * Return: 0
888  */
889 static int ti_abb_remove(struct platform_device *pdev)
890 {
891 	struct regulator_dev *rdev = platform_get_drvdata(pdev);
892 
893 	regulator_unregister(rdev);
894 	return 0;
895 }
896 
897 MODULE_ALIAS("platform:ti_abb");
898 
899 static struct platform_driver ti_abb_driver = {
900 	.probe = ti_abb_probe,
901 	.remove = ti_abb_remove,
902 	.driver = {
903 		   .name = "ti_abb",
904 		   .owner = THIS_MODULE,
905 		   .of_match_table = of_match_ptr(ti_abb_of_match),
906 		   },
907 };
908 module_platform_driver(ti_abb_driver);
909 
910 MODULE_DESCRIPTION("Texas Instruments ABB LDO regulator driver");
911 MODULE_AUTHOR("Texas Instruments Inc.");
912 MODULE_LICENSE("GPL v2");
913