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powercap: restrict energy meter to root access
[linux/fpc-iii.git] / drivers / gpio / gpio-stmpe.c
blobabb5a27525110c1ea11e4bc85b43e6baf5bc56d1
1 /*
2 * Copyright (C) ST-Ericsson SA 2010
3 *
4 * License Terms: GNU General Public License, version 2
5 * Author: Rabin Vincent <rabin.vincent@stericsson.com> for ST-Ericsson
6 */
7
8 #include <linux/init.h>
9 #include <linux/platform_device.h>
10 #include <linux/slab.h>
11 #include <linux/gpio.h>
12 #include <linux/interrupt.h>
13 #include <linux/of.h>
14 #include <linux/mfd/stmpe.h>
15 #include <linux/seq_file.h>
16 #include <linux/bitops.h>
17
18 /*
19 * These registers are modified under the irq bus lock and cached to avoid
20 * unnecessary writes in bus_sync_unlock.
21 */
22 enum { REG_RE, REG_FE, REG_IE };
23
24 enum { LSB, CSB, MSB };
25
26 #define CACHE_NR_REGS 3
27 /* No variant has more than 24 GPIOs */
28 #define CACHE_NR_BANKS (24 / 8)
29
30 struct stmpe_gpio {
31 struct gpio_chip chip;
32 struct stmpe *stmpe;
33 struct device *dev;
34 struct mutex irq_lock;
35 u32 norequest_mask;
36 /* Caches of interrupt control registers for bus_lock */
37 u8 regs[CACHE_NR_REGS][CACHE_NR_BANKS];
38 u8 oldregs[CACHE_NR_REGS][CACHE_NR_BANKS];
39 };
40
41 static int stmpe_gpio_get(struct gpio_chip *chip, unsigned offset)
42 {
43 struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(chip);
44 struct stmpe *stmpe = stmpe_gpio->stmpe;
45 u8 reg = stmpe->regs[STMPE_IDX_GPMR_LSB + (offset / 8)];
46 u8 mask = BIT(offset % 8);
47 int ret;
48
49 ret = stmpe_reg_read(stmpe, reg);
50 if (ret < 0)
51 return ret;
52
53 return !!(ret & mask);
54 }
55
56 static void stmpe_gpio_set(struct gpio_chip *chip, unsigned offset, int val)
57 {
58 struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(chip);
59 struct stmpe *stmpe = stmpe_gpio->stmpe;
60 int which = val ? STMPE_IDX_GPSR_LSB : STMPE_IDX_GPCR_LSB;
61 u8 reg = stmpe->regs[which + (offset / 8)];
62 u8 mask = BIT(offset % 8);
63
64 /*
65 * Some variants have single register for gpio set/clear functionality.
66 * For them we need to write 0 to clear and 1 to set.
67 */
68 if (stmpe->regs[STMPE_IDX_GPSR_LSB] == stmpe->regs[STMPE_IDX_GPCR_LSB])
69 stmpe_set_bits(stmpe, reg, mask, val ? mask : 0);
70 else
71 stmpe_reg_write(stmpe, reg, mask);
72 }
73
74 static int stmpe_gpio_get_direction(struct gpio_chip *chip,
75 unsigned offset)
76 {
77 struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(chip);
78 struct stmpe *stmpe = stmpe_gpio->stmpe;
79 u8 reg = stmpe->regs[STMPE_IDX_GPDR_LSB] - (offset / 8);
80 u8 mask = BIT(offset % 8);
81 int ret;
82
83 ret = stmpe_reg_read(stmpe, reg);
84 if (ret < 0)
85 return ret;
86
87 return !(ret & mask);
88 }
89
90 static int stmpe_gpio_direction_output(struct gpio_chip *chip,
91 unsigned offset, int val)
92 {
93 struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(chip);
94 struct stmpe *stmpe = stmpe_gpio->stmpe;
95 u8 reg = stmpe->regs[STMPE_IDX_GPDR_LSB + (offset / 8)];
96 u8 mask = BIT(offset % 8);
97
98 stmpe_gpio_set(chip, offset, val);
99
100 return stmpe_set_bits(stmpe, reg, mask, mask);
101 }
102
103 static int stmpe_gpio_direction_input(struct gpio_chip *chip,
104 unsigned offset)
105 {
106 struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(chip);
107 struct stmpe *stmpe = stmpe_gpio->stmpe;
108 u8 reg = stmpe->regs[STMPE_IDX_GPDR_LSB + (offset / 8)];
109 u8 mask = BIT(offset % 8);
110
111 return stmpe_set_bits(stmpe, reg, mask, 0);
112 }
113
114 static int stmpe_gpio_request(struct gpio_chip *chip, unsigned offset)
115 {
116 struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(chip);
117 struct stmpe *stmpe = stmpe_gpio->stmpe;
118
119 if (stmpe_gpio->norequest_mask & BIT(offset))
120 return -EINVAL;
121
122 return stmpe_set_altfunc(stmpe, BIT(offset), STMPE_BLOCK_GPIO);
123 }
124
125 static const struct gpio_chip template_chip = {
126 .label = "stmpe",
127 .owner = THIS_MODULE,
128 .get_direction = stmpe_gpio_get_direction,
129 .direction_input = stmpe_gpio_direction_input,
130 .get = stmpe_gpio_get,
131 .direction_output = stmpe_gpio_direction_output,
132 .set = stmpe_gpio_set,
133 .request = stmpe_gpio_request,
134 .can_sleep = true,
135 };
136
137 static int stmpe_gpio_irq_set_type(struct irq_data *d, unsigned int type)
138 {
139 struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
140 struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(gc);
141 int offset = d->hwirq;
142 int regoffset = offset / 8;
143 int mask = BIT(offset % 8);
144
145 if (type & IRQ_TYPE_LEVEL_LOW || type & IRQ_TYPE_LEVEL_HIGH)
146 return -EINVAL;
147
148 /* STMPE801 and STMPE 1600 don't have RE and FE registers */
149 if (stmpe_gpio->stmpe->partnum == STMPE801 ||
150 stmpe_gpio->stmpe->partnum == STMPE1600)
151 return 0;
152
153 if (type & IRQ_TYPE_EDGE_RISING)
154 stmpe_gpio->regs[REG_RE][regoffset] |= mask;
155 else
156 stmpe_gpio->regs[REG_RE][regoffset] &= ~mask;
157
158 if (type & IRQ_TYPE_EDGE_FALLING)
159 stmpe_gpio->regs[REG_FE][regoffset] |= mask;
160 else
161 stmpe_gpio->regs[REG_FE][regoffset] &= ~mask;
162
163 return 0;
164 }
165
166 static void stmpe_gpio_irq_lock(struct irq_data *d)
167 {
168 struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
169 struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(gc);
170
171 mutex_lock(&stmpe_gpio->irq_lock);
172 }
173
174 static void stmpe_gpio_irq_sync_unlock(struct irq_data *d)
175 {
176 struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
177 struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(gc);
178 struct stmpe *stmpe = stmpe_gpio->stmpe;
179 int num_banks = DIV_ROUND_UP(stmpe->num_gpios, 8);
180 static const u8 regmap[CACHE_NR_REGS][CACHE_NR_BANKS] = {
181 [REG_RE][LSB] = STMPE_IDX_GPRER_LSB,
182 [REG_RE][CSB] = STMPE_IDX_GPRER_CSB,
183 [REG_RE][MSB] = STMPE_IDX_GPRER_MSB,
184 [REG_FE][LSB] = STMPE_IDX_GPFER_LSB,
185 [REG_FE][CSB] = STMPE_IDX_GPFER_CSB,
186 [REG_FE][MSB] = STMPE_IDX_GPFER_MSB,
187 [REG_IE][LSB] = STMPE_IDX_IEGPIOR_LSB,
188 [REG_IE][CSB] = STMPE_IDX_IEGPIOR_CSB,
189 [REG_IE][MSB] = STMPE_IDX_IEGPIOR_MSB,
190 };
191 int i, j;
192
193 /*
194 * STMPE1600: to be able to get IRQ from pins,
195 * a read must be done on GPMR register, or a write in
196 * GPSR or GPCR registers
197 */
198 if (stmpe->partnum == STMPE1600) {
199 stmpe_reg_read(stmpe, stmpe->regs[STMPE_IDX_GPMR_LSB]);
200 stmpe_reg_read(stmpe, stmpe->regs[STMPE_IDX_GPMR_CSB]);
201 }
202
203 for (i = 0; i < CACHE_NR_REGS; i++) {
204 /* STMPE801 and STMPE1600 don't have RE and FE registers */
205 if ((stmpe->partnum == STMPE801 ||
206 stmpe->partnum == STMPE1600) &&
207 (i != REG_IE))
208 continue;
209
210 for (j = 0; j < num_banks; j++) {
211 u8 old = stmpe_gpio->oldregs[i][j];
212 u8 new = stmpe_gpio->regs[i][j];
213
214 if (new == old)
215 continue;
216
217 stmpe_gpio->oldregs[i][j] = new;
218 stmpe_reg_write(stmpe, stmpe->regs[regmap[i][j]], new);
219 }
220 }
221
222 mutex_unlock(&stmpe_gpio->irq_lock);
223 }
224
225 static void stmpe_gpio_irq_mask(struct irq_data *d)
226 {
227 struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
228 struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(gc);
229 int offset = d->hwirq;
230 int regoffset = offset / 8;
231 int mask = BIT(offset % 8);
232
233 stmpe_gpio->regs[REG_IE][regoffset] &= ~mask;
234 }
235
236 static void stmpe_gpio_irq_unmask(struct irq_data *d)
237 {
238 struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
239 struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(gc);
240 int offset = d->hwirq;
241 int regoffset = offset / 8;
242 int mask = BIT(offset % 8);
243
244 stmpe_gpio->regs[REG_IE][regoffset] |= mask;
245 }
246
247 static void stmpe_dbg_show_one(struct seq_file *s,
248 struct gpio_chip *gc,
249 unsigned offset, unsigned gpio)
250 {
251 struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(gc);
252 struct stmpe *stmpe = stmpe_gpio->stmpe;
253 const char *label = gpiochip_is_requested(gc, offset);
254 bool val = !!stmpe_gpio_get(gc, offset);
255 u8 bank = offset / 8;
256 u8 dir_reg = stmpe->regs[STMPE_IDX_GPDR_LSB + bank];
257 u8 mask = BIT(offset % 8);
258 int ret;
259 u8 dir;
260
261 ret = stmpe_reg_read(stmpe, dir_reg);
262 if (ret < 0)
263 return;
264 dir = !!(ret & mask);
265
266 if (dir) {
267 seq_printf(s, " gpio-%-3d (%-20.20s) out %s",
268 gpio, label ?: "(none)",
269 val ? "hi" : "lo");
270 } else {
271 u8 edge_det_reg;
272 u8 rise_reg;
273 u8 fall_reg;
274 u8 irqen_reg;
275
276 char *edge_det_values[] = {"edge-inactive",
277 "edge-asserted",
278 "not-supported"};
279 char *rise_values[] = {"no-rising-edge-detection",
280 "rising-edge-detection",
281 "not-supported"};
282 char *fall_values[] = {"no-falling-edge-detection",
283 "falling-edge-detection",
284 "not-supported"};
285 #define NOT_SUPPORTED_IDX 2
286 u8 edge_det = NOT_SUPPORTED_IDX;
287 u8 rise = NOT_SUPPORTED_IDX;
288 u8 fall = NOT_SUPPORTED_IDX;
289 bool irqen;
290
291 switch (stmpe->partnum) {
292 case STMPE610:
293 case STMPE811:
294 case STMPE1601:
295 case STMPE2401:
296 case STMPE2403:
297 edge_det_reg = stmpe->regs[STMPE_IDX_GPEDR_LSB + bank];
298 ret = stmpe_reg_read(stmpe, edge_det_reg);
299 if (ret < 0)
300 return;
301 edge_det = !!(ret & mask);
302
303 case STMPE1801:
304 rise_reg = stmpe->regs[STMPE_IDX_GPRER_LSB + bank];
305 fall_reg = stmpe->regs[STMPE_IDX_GPFER_LSB + bank];
306
307 ret = stmpe_reg_read(stmpe, rise_reg);
308 if (ret < 0)
309 return;
310 rise = !!(ret & mask);
311 ret = stmpe_reg_read(stmpe, fall_reg);
312 if (ret < 0)
313 return;
314 fall = !!(ret & mask);
315
316 case STMPE801:
317 case STMPE1600:
318 irqen_reg = stmpe->regs[STMPE_IDX_IEGPIOR_LSB + bank];
319 break;
320
321 default:
322 return;
323 }
324
325 ret = stmpe_reg_read(stmpe, irqen_reg);
326 if (ret < 0)
327 return;
328 irqen = !!(ret & mask);
329
330 seq_printf(s, " gpio-%-3d (%-20.20s) in %s %13s %13s %25s %25s",
331 gpio, label ?: "(none)",
332 val ? "hi" : "lo",
333 edge_det_values[edge_det],
334 irqen ? "IRQ-enabled" : "IRQ-disabled",
335 rise_values[rise],
336 fall_values[fall]);
337 }
338 }
339
340 static void stmpe_dbg_show(struct seq_file *s, struct gpio_chip *gc)
341 {
342 unsigned i;
343 unsigned gpio = gc->base;
344
345 for (i = 0; i < gc->ngpio; i++, gpio++) {
346 stmpe_dbg_show_one(s, gc, i, gpio);
347 seq_printf(s, "\n");
348 }
349 }
350
351 static struct irq_chip stmpe_gpio_irq_chip = {
352 .name = "stmpe-gpio",
353 .irq_bus_lock = stmpe_gpio_irq_lock,
354 .irq_bus_sync_unlock = stmpe_gpio_irq_sync_unlock,
355 .irq_mask = stmpe_gpio_irq_mask,
356 .irq_unmask = stmpe_gpio_irq_unmask,
357 .irq_set_type = stmpe_gpio_irq_set_type,
358 };
359
360 static irqreturn_t stmpe_gpio_irq(int irq, void *dev)
361 {
362 struct stmpe_gpio *stmpe_gpio = dev;
363 struct stmpe *stmpe = stmpe_gpio->stmpe;
364 u8 statmsbreg;
365 int num_banks = DIV_ROUND_UP(stmpe->num_gpios, 8);
366 u8 status[num_banks];
367 int ret;
368 int i;
369
370 /*
371 * the stmpe_block_read() call below, imposes to set statmsbreg
372 * with the register located at the lowest address. As STMPE1600
373 * variant is the only one which respect registers address's order
374 * (LSB regs located at lowest address than MSB ones) whereas all
375 * the others have a registers layout with MSB located before the
376 * LSB regs.
377 */
378 if (stmpe->partnum == STMPE1600)
379 statmsbreg = stmpe->regs[STMPE_IDX_ISGPIOR_LSB];
380 else
381 statmsbreg = stmpe->regs[STMPE_IDX_ISGPIOR_MSB];
382
383 ret = stmpe_block_read(stmpe, statmsbreg, num_banks, status);
384 if (ret < 0)
385 return IRQ_NONE;
386
387 for (i = 0; i < num_banks; i++) {
388 int bank = (stmpe_gpio->stmpe->partnum == STMPE1600) ? i :
389 num_banks - i - 1;
390 unsigned int enabled = stmpe_gpio->regs[REG_IE][bank];
391 unsigned int stat = status[i];
392
393 stat &= enabled;
394 if (!stat)
395 continue;
396
397 while (stat) {
398 int bit = __ffs(stat);
399 int line = bank * 8 + bit;
400 int child_irq = irq_find_mapping(stmpe_gpio->chip.irqdomain,
401 line);
402
403 handle_nested_irq(child_irq);
404 stat &= ~BIT(bit);
405 }
406
407 /*
408 * interrupt status register write has no effect on
409 * 801/1801/1600, bits are cleared when read.
410 * Edge detect register is not present on 801/1600/1801
411 */
412 if (stmpe->partnum != STMPE801 && stmpe->partnum != STMPE1600 &&
413 stmpe->partnum != STMPE1801) {
414 stmpe_reg_write(stmpe, statmsbreg + i, status[i]);
415 stmpe_reg_write(stmpe,
416 stmpe->regs[STMPE_IDX_GPEDR_MSB] + i,
417 status[i]);
418 }
419 }
420
421 return IRQ_HANDLED;
422 }
423
424 static int stmpe_gpio_probe(struct platform_device *pdev)
425 {
426 struct stmpe *stmpe = dev_get_drvdata(pdev->dev.parent);
427 struct device_node *np = pdev->dev.of_node;
428 struct stmpe_gpio *stmpe_gpio;
429 int ret;
430 int irq = 0;
431
432 irq = platform_get_irq(pdev, 0);
433
434 stmpe_gpio = kzalloc(sizeof(struct stmpe_gpio), GFP_KERNEL);
435 if (!stmpe_gpio)
436 return -ENOMEM;
437
438 mutex_init(&stmpe_gpio->irq_lock);
439
440 stmpe_gpio->dev = &pdev->dev;
441 stmpe_gpio->stmpe = stmpe;
442 stmpe_gpio->chip = template_chip;
443 stmpe_gpio->chip.ngpio = stmpe->num_gpios;
444 stmpe_gpio->chip.parent = &pdev->dev;
445 stmpe_gpio->chip.of_node = np;
446 stmpe_gpio->chip.base = -1;
447
448 if (IS_ENABLED(CONFIG_DEBUG_FS))
449 stmpe_gpio->chip.dbg_show = stmpe_dbg_show;
450
451 of_property_read_u32(np, "st,norequest-mask",
452 &stmpe_gpio->norequest_mask);
453 if (stmpe_gpio->norequest_mask)
454 stmpe_gpio->chip.irq_need_valid_mask = true;
455
456 if (irq < 0)
457 dev_info(&pdev->dev,
458 "device configured in no-irq mode: "
459 "irqs are not available\n");
460
461 ret = stmpe_enable(stmpe, STMPE_BLOCK_GPIO);
462 if (ret)
463 goto out_free;
464
465 ret = gpiochip_add_data(&stmpe_gpio->chip, stmpe_gpio);
466 if (ret) {
467 dev_err(&pdev->dev, "unable to add gpiochip: %d\n", ret);
468 goto out_disable;
469 }
470
471 if (irq > 0) {
472 ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
473 stmpe_gpio_irq, IRQF_ONESHOT,
474 "stmpe-gpio", stmpe_gpio);
475 if (ret) {
476 dev_err(&pdev->dev, "unable to get irq: %d\n", ret);
477 goto out_disable;
478 }
479 if (stmpe_gpio->norequest_mask) {
480 int i;
481
482 /* Forbid unused lines to be mapped as IRQs */
483 for (i = 0; i < sizeof(u32); i++)
484 if (stmpe_gpio->norequest_mask & BIT(i))
485 clear_bit(i, stmpe_gpio->chip.irq_valid_mask);
486 }
487 ret = gpiochip_irqchip_add(&stmpe_gpio->chip,
488 &stmpe_gpio_irq_chip,
489 0,
490 handle_simple_irq,
491 IRQ_TYPE_NONE);
492 if (ret) {
493 dev_err(&pdev->dev,
494 "could not connect irqchip to gpiochip\n");
495 goto out_disable;
496 }
497
498 gpiochip_set_chained_irqchip(&stmpe_gpio->chip,
499 &stmpe_gpio_irq_chip,
500 irq,
501 NULL);
502 }
503
504 platform_set_drvdata(pdev, stmpe_gpio);
505
506 return 0;
507
508 out_disable:
509 stmpe_disable(stmpe, STMPE_BLOCK_GPIO);
510 gpiochip_remove(&stmpe_gpio->chip);
511 out_free:
512 kfree(stmpe_gpio);
513 return ret;
514 }
515
516 static struct platform_driver stmpe_gpio_driver = {
517 .driver = {
518 .suppress_bind_attrs = true,
519 .name = "stmpe-gpio",
520 },
521 .probe = stmpe_gpio_probe,
522 };
523
524 static int __init stmpe_gpio_init(void)
525 {
526 return platform_driver_register(&stmpe_gpio_driver);
527 }
528 subsys_initcall(stmpe_gpio_init);
Linux with added FPC-III support