summaryrefslogtreecommitdiff
path: root/drivers/pinctrl/aspeed/pinctrl-aspeed.c
blob: 49aeba91253198c644794c23cb4877368f6905ad (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
/*
 * Copyright (C) 2016 IBM Corp.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

#include <linux/mfd/syscon.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/string.h>
#include "../core.h"
#include "pinctrl-aspeed.h"

int aspeed_pinctrl_get_groups_count(struct pinctrl_dev *pctldev)
{
	struct aspeed_pinctrl_data *pdata = pinctrl_dev_get_drvdata(pctldev);

	return pdata->ngroups;
}

const char *aspeed_pinctrl_get_group_name(struct pinctrl_dev *pctldev,
		unsigned int group)
{
	struct aspeed_pinctrl_data *pdata = pinctrl_dev_get_drvdata(pctldev);

	return pdata->groups[group].name;
}

int aspeed_pinctrl_get_group_pins(struct pinctrl_dev *pctldev,
				  unsigned int group, const unsigned int **pins,
				  unsigned int *npins)
{
	struct aspeed_pinctrl_data *pdata = pinctrl_dev_get_drvdata(pctldev);

	*pins = &pdata->groups[group].pins[0];
	*npins = pdata->groups[group].npins;

	return 0;
}

void aspeed_pinctrl_pin_dbg_show(struct pinctrl_dev *pctldev,
				 struct seq_file *s, unsigned int offset)
{
	seq_printf(s, " %s", dev_name(pctldev->dev));
}

int aspeed_pinmux_get_fn_count(struct pinctrl_dev *pctldev)
{
	struct aspeed_pinctrl_data *pdata = pinctrl_dev_get_drvdata(pctldev);

	return pdata->nfunctions;
}

const char *aspeed_pinmux_get_fn_name(struct pinctrl_dev *pctldev,
				      unsigned int function)
{
	struct aspeed_pinctrl_data *pdata = pinctrl_dev_get_drvdata(pctldev);

	return pdata->functions[function].name;
}

int aspeed_pinmux_get_fn_groups(struct pinctrl_dev *pctldev,
				unsigned int function,
				const char * const **groups,
				unsigned int * const num_groups)
{
	struct aspeed_pinctrl_data *pdata = pinctrl_dev_get_drvdata(pctldev);

	*groups = pdata->functions[function].groups;
	*num_groups = pdata->functions[function].ngroups;

	return 0;
}

static inline void aspeed_sig_desc_print_val(
		const struct aspeed_sig_desc *desc, bool enable, u32 rv)
{
	pr_debug("SCU%x[0x%08x]=0x%x, got 0x%x from 0x%08x\n", desc->reg,
			desc->mask, enable ? desc->enable : desc->disable,
			(rv & desc->mask) >> __ffs(desc->mask), rv);
}

/**
 * Query the enabled or disabled state of a signal descriptor
 *
 * @desc: The signal descriptor of interest
 * @enabled: True to query the enabled state, false to query disabled state
 * @regmap: The SCU regmap instance
 *
 * @return True if the descriptor's bitfield is configured to the state
 * selected by @enabled, false otherwise
 *
 * Evaluation of descriptor state is non-trivial in that it is not a binary
 * outcome: The bitfields can be greater than one bit in size and thus can take
 * a value that is neither the enabled nor disabled state recorded in the
 * descriptor (typically this means a different function to the one of interest
 * is enabled). Thus we must explicitly test for either condition as required.
 */
static bool aspeed_sig_desc_eval(const struct aspeed_sig_desc *desc,
				 bool enabled, struct regmap *map)
{
	unsigned int raw;
	u32 want;

	if (regmap_read(map, desc->reg, &raw) < 0)
		return false;

	aspeed_sig_desc_print_val(desc, enabled, raw);
	want = enabled ? desc->enable : desc->disable;

	return ((raw & desc->mask) >> __ffs(desc->mask)) == want;
}

/**
 * Query the enabled or disabled state for a mux function's signal on a pin
 *
 * @expr: An expression controlling the signal for a mux function on a pin
 * @enabled: True to query the enabled state, false to query disabled state
 * @regmap: The SCU regmap instance
 *
 * @return True if the expression composed by @enabled evaluates true, false
 * otherwise
 *
 * A mux function is enabled or disabled if the function's signal expression
 * for each pin in the function's pin group evaluates true for the desired
 * state. An signal expression evaluates true if all of its associated signal
 * descriptors evaluate true for the desired state.
 *
 * If an expression's state is described by more than one bit, either through
 * multi-bit bitfields in a single signal descriptor or through multiple signal
 * descriptors of a single bit then it is possible for the expression to be in
 * neither the enabled nor disabled state. Thus we must explicitly test for
 * either condition as required.
 */
static bool aspeed_sig_expr_eval(const struct aspeed_sig_expr *expr,
				 bool enabled, struct regmap *map)
{
	int i;

	for (i = 0; i < expr->ndescs; i++) {
		const struct aspeed_sig_desc *desc = &expr->descs[i];

		if (!aspeed_sig_desc_eval(desc, enabled, map))
			return false;
	}

	return true;
}

/**
 * Configure a pin's signal by applying an expression's descriptor state for
 * all descriptors in the expression.
 *
 * @expr: The expression associated with the function whose signal is to be
 *        configured
 * @enable: true to enable an function's signal through a pin's signal
 *          expression, false to disable the function's signal
 * @map: The SCU's regmap instance for pinmux register access.
 *
 * @return true if the expression is configured as requested, false otherwise
 */
static bool aspeed_sig_expr_set(const struct aspeed_sig_expr *expr,
				bool enable, struct regmap *map)
{
	int i;

	for (i = 0; i < expr->ndescs; i++) {
		bool ret;
		const struct aspeed_sig_desc *desc = &expr->descs[i];
		u32 pattern = enable ? desc->enable : desc->disable;

		/*
		 * Strap registers are configured in hardware or by early-boot
		 * firmware. Treat them as read-only despite that we can write
		 * them. This may mean that certain functions cannot be
		 * deconfigured and is the reason we re-evaluate after writing
		 * all descriptor bits.
		 */
		if (desc->reg == HW_STRAP1 || desc->reg == HW_STRAP2)
			continue;

		ret = regmap_update_bits(map, desc->reg, desc->mask,
				pattern << __ffs(desc->mask)) == 0;

		if (!ret)
			return ret;
	}

	return aspeed_sig_expr_eval(expr, enable, map);
}

static bool aspeed_sig_expr_enable(const struct aspeed_sig_expr *expr,
				   struct regmap *map)
{
	if (aspeed_sig_expr_eval(expr, true, map))
		return true;

	return aspeed_sig_expr_set(expr, true, map);
}

static bool aspeed_sig_expr_disable(const struct aspeed_sig_expr *expr,
				    struct regmap *map)
{
	if (!aspeed_sig_expr_eval(expr, true, map))
		return true;

	return aspeed_sig_expr_set(expr, false, map);
}

/**
 * Disable a signal on a pin by disabling all provided signal expressions.
 *
 * @exprs: The list of signal expressions (from a priority level on a pin)
 * @map: The SCU's regmap instance for pinmux register access.
 *
 * @return true if all expressions in the list are successfully disabled, false
 * otherwise
 */
static bool aspeed_disable_sig(const struct aspeed_sig_expr **exprs,
			       struct regmap *map)
{
	bool disabled = true;

	if (!exprs)
		return true;

	while (*exprs) {
		bool ret;

		ret = aspeed_sig_expr_disable(*exprs, map);
		disabled = disabled && ret;

		exprs++;
	}

	return disabled;
}

/**
 * Search for the signal expression needed to enable the pin's signal for the
 * requested function.
 *
 * @exprs: List of signal expressions (haystack)
 * @name: The name of the requested function (needle)
 *
 * @return A pointer to the signal expression whose function tag matches the
 *         provided name, otherwise NULL.
 *
 */
static const struct aspeed_sig_expr *aspeed_find_expr_by_name(
		const struct aspeed_sig_expr **exprs, const char *name)
{
	while (*exprs) {
		if (strcmp((*exprs)->function, name) == 0)
			return *exprs;
		exprs++;
	}

	return NULL;
}

static char *get_defined_attribute(const struct aspeed_pin_desc *pdesc,
				   const char *(*get)(
					   const struct aspeed_sig_expr *))
{
	char *found = NULL;
	size_t len = 0;
	const struct aspeed_sig_expr ***prios, **funcs, *expr;

	prios = pdesc->prios;

	while ((funcs = *prios)) {
		while ((expr = *funcs)) {
			const char *str = get(expr);
			size_t delta = strlen(str) + 2;
			char *expanded;

			expanded = krealloc(found, len + delta + 1, GFP_KERNEL);
			if (!expanded) {
				kfree(found);
				return expanded;
			}

			found = expanded;
			found[len] = '\0';
			len += delta;

			strcat(found, str);
			strcat(found, ", ");

			funcs++;
		}
		prios++;
	}

	if (len < 2) {
		kfree(found);
		return NULL;
	}

	found[len - 2] = '\0';

	return found;
}

static const char *aspeed_sig_expr_function(const struct aspeed_sig_expr *expr)
{
	return expr->function;
}

static char *get_defined_functions(const struct aspeed_pin_desc *pdesc)
{
	return get_defined_attribute(pdesc, aspeed_sig_expr_function);
}

static const char *aspeed_sig_expr_signal(const struct aspeed_sig_expr *expr)
{
	return expr->signal;
}

static char *get_defined_signals(const struct aspeed_pin_desc *pdesc)
{
	return get_defined_attribute(pdesc, aspeed_sig_expr_signal);
}

int aspeed_pinmux_set_mux(struct pinctrl_dev *pctldev, unsigned int function,
			  unsigned int group)
{
	int i;
	const struct aspeed_pinctrl_data *pdata =
		pinctrl_dev_get_drvdata(pctldev);
	const struct aspeed_pin_group *pgroup = &pdata->groups[group];
	const struct aspeed_pin_function *pfunc =
		&pdata->functions[function];

	for (i = 0; i < pgroup->npins; i++) {
		int pin = pgroup->pins[i];
		const struct aspeed_pin_desc *pdesc = pdata->pins[pin].drv_data;
		const struct aspeed_sig_expr *expr = NULL;
		const struct aspeed_sig_expr **funcs;
		const struct aspeed_sig_expr ***prios;

		if (!pdesc)
			return -EINVAL;

		prios = pdesc->prios;

		if (!prios)
			continue;

		/* Disable functions at a higher priority than that requested */
		while ((funcs = *prios)) {
			expr = aspeed_find_expr_by_name(funcs, pfunc->name);

			if (expr)
				break;

			if (!aspeed_disable_sig(funcs, pdata->map))
				return -EPERM;

			prios++;
		}

		if (!expr) {
			char *functions = get_defined_functions(pdesc);
			char *signals = get_defined_signals(pdesc);

			pr_warn("No function %s found on pin %s (%d). Found signal(s) %s for function(s) %s\n",
				pfunc->name, pdesc->name, pin, signals,
				functions);
			kfree(signals);
			kfree(functions);

			return -ENXIO;
		}

		if (!aspeed_sig_expr_enable(expr, pdata->map))
			return -EPERM;
	}

	return 0;
}

static bool aspeed_expr_is_gpio(const struct aspeed_sig_expr *expr)
{
	/*
	 * The signal type is GPIO if the signal name has "GPIO" as a prefix.
	 * strncmp (rather than strcmp) is used to implement the prefix
	 * requirement.
	 *
	 * expr->signal might look like "GPIOT3" in the GPIO case.
	 */
	return strncmp(expr->signal, "GPIO", 4) == 0;
}

static bool aspeed_gpio_in_exprs(const struct aspeed_sig_expr **exprs)
{
	if (!exprs)
		return false;

	while (*exprs) {
		if (aspeed_expr_is_gpio(*exprs))
			return true;
		exprs++;
	}

	return false;
}

int aspeed_gpio_request_enable(struct pinctrl_dev *pctldev,
			       struct pinctrl_gpio_range *range,
			       unsigned int offset)
{
	const struct aspeed_pinctrl_data *pdata =
		pinctrl_dev_get_drvdata(pctldev);
	const struct aspeed_pin_desc *pdesc = pdata->pins[offset].drv_data;
	const struct aspeed_sig_expr ***prios, **funcs, *expr;

	if (!pdesc)
		return -EINVAL;

	prios = pdesc->prios;

	if (!prios)
		return -ENXIO;

	/* Disable any functions of higher priority than GPIO */
	while ((funcs = *prios)) {
		if (aspeed_gpio_in_exprs(funcs))
			break;

		if (!aspeed_disable_sig(funcs, pdata->map))
			return -EPERM;

		prios++;
	}

	if (!funcs) {
		char *signals = get_defined_signals(pdesc);

		pr_warn("No GPIO signal type found on pin %s (%d). Found: %s\n",
			pdesc->name, offset, signals);
		kfree(signals);

		return -ENXIO;
	}

	expr = *funcs;

	/*
	 * Disabling all higher-priority expressions is enough to enable the
	 * lowest-priority signal type. As such it has no associated
	 * expression.
	 */
	if (!expr)
		return 0;

	/*
	 * If GPIO is not the lowest priority signal type, assume there is only
	 * one expression defined to enable the GPIO function
	 */
	if (!aspeed_sig_expr_enable(expr, pdata->map))
		return -EPERM;

	return 0;
}

int aspeed_pinctrl_probe(struct platform_device *pdev,
			 struct pinctrl_desc *pdesc,
			 struct aspeed_pinctrl_data *pdata)
{
	struct device *parent;
	struct pinctrl_dev *pctl;

	parent = pdev->dev.parent;
	if (!parent) {
		dev_err(&pdev->dev, "No parent for syscon pincontroller\n");
		return -ENODEV;
	}

	pdata->map = syscon_node_to_regmap(parent->of_node);
	if (IS_ERR(pdata->map)) {
		dev_err(&pdev->dev, "No regmap for syscon pincontroller parent\n");
		return PTR_ERR(pdata->map);
	}

	pctl = pinctrl_register(pdesc, &pdev->dev, pdata);

	if (IS_ERR(pctl)) {
		dev_err(&pdev->dev, "Failed to register pinctrl\n");
		return PTR_ERR(pctl);
	}

	platform_set_drvdata(pdev, pdata);

	return 0;
}