Root/drivers/gpio/gpio-generic.c

1/*
2 * Generic driver for memory-mapped GPIO controllers.
3 *
4 * Copyright 2008 MontaVista Software, Inc.
5 * Copyright 2008,2010 Anton Vorontsov <cbouatmailru@gmail.com>
6 *
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License as published by the
9 * Free Software Foundation; either version 2 of the License, or (at your
10 * option) any later version.
11 *
12 * ....``.```~~~~````.`.`.`.`.```````'',,,.........`````......`.......
13 * ...`` ```````..
14 * ..The simplest form of a GPIO controller that the driver supports is``
15 * `.just a single "data" register, where GPIO state can be read and/or `
16 * `,..written. ,,..``~~~~ .....``.`.`.~~.```.`.........``````.```````
17 * `````````
18                                    ___
19_/~~|___/~| . ```~~~~~~ ___/___\___ ,~.`.`.`.`````.~~...,,,,...
20__________|~$@~~~ %~ /o*o*o*o*o*o\ .. Implementing such a GPIO .
21o ` ~~~~\___/~~~~ ` controller in FPGA is ,.`
22                                                 `....trivial..'~`.```.```
23 * ```````
24 * .```````~~~~`..`.``.``.
25 * . The driver supports `... ,..```.`~~~```````````````....````.``,,
26 * . big-endian notation, just`. .. A bit more sophisticated controllers ,
27 * . register the device with -be`. .with a pair of set/clear-bit registers ,
28 * `.. suffix. ```~~`````....`.` . affecting the data register and the .`
29 * ``.`.``...``` ```.. output pins are also supported.`
30 * ^^ `````.`````````.,``~``~``~~``````
31 * . ^^
32 * ,..`.`.`...````````````......`.`.`.`.`.`..`.`.`..
33 * .. The expectation is that in at least some cases . ,-~~~-,
34 * .this will be used with roll-your-own ASIC/FPGA .` \ /
35 * .logic in Verilog or VHDL. ~~~`````````..`````~~` \ /
36 * ..````````......``````````` \o_
37 * |
38 * ^^ / \
39 *
40 * ...`````~~`.....``.`..........``````.`.``.```........``.
41 * ` 8, 16, 32 and 64 bits registers are supported, and``.
42 * . the number of GPIOs is determined by the width of ~
43 * .. the registers. ,............```.`.`..`.`.~~~.`.`.`~
44 * `.......````.```
45 */
46
47#include <linux/init.h>
48#include <linux/err.h>
49#include <linux/bug.h>
50#include <linux/kernel.h>
51#include <linux/module.h>
52#include <linux/spinlock.h>
53#include <linux/compiler.h>
54#include <linux/types.h>
55#include <linux/errno.h>
56#include <linux/log2.h>
57#include <linux/ioport.h>
58#include <linux/io.h>
59#include <linux/gpio.h>
60#include <linux/slab.h>
61#include <linux/platform_device.h>
62#include <linux/mod_devicetable.h>
63#include <linux/basic_mmio_gpio.h>
64
65static void bgpio_write8(void __iomem *reg, unsigned long data)
66{
67    writeb(data, reg);
68}
69
70static unsigned long bgpio_read8(void __iomem *reg)
71{
72    return readb(reg);
73}
74
75static void bgpio_write16(void __iomem *reg, unsigned long data)
76{
77    writew(data, reg);
78}
79
80static unsigned long bgpio_read16(void __iomem *reg)
81{
82    return readw(reg);
83}
84
85static void bgpio_write32(void __iomem *reg, unsigned long data)
86{
87    writel(data, reg);
88}
89
90static unsigned long bgpio_read32(void __iomem *reg)
91{
92    return readl(reg);
93}
94
95#if BITS_PER_LONG >= 64
96static void bgpio_write64(void __iomem *reg, unsigned long data)
97{
98    writeq(data, reg);
99}
100
101static unsigned long bgpio_read64(void __iomem *reg)
102{
103    return readq(reg);
104}
105#endif /* BITS_PER_LONG >= 64 */
106
107static unsigned long bgpio_pin2mask(struct bgpio_chip *bgc, unsigned int pin)
108{
109    return 1 << pin;
110}
111
112static unsigned long bgpio_pin2mask_be(struct bgpio_chip *bgc,
113                       unsigned int pin)
114{
115    return 1 << (bgc->bits - 1 - pin);
116}
117
118static int bgpio_get(struct gpio_chip *gc, unsigned int gpio)
119{
120    struct bgpio_chip *bgc = to_bgpio_chip(gc);
121
122    return bgc->read_reg(bgc->reg_dat) & bgc->pin2mask(bgc, gpio);
123}
124
125static void bgpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
126{
127    struct bgpio_chip *bgc = to_bgpio_chip(gc);
128    unsigned long mask = bgc->pin2mask(bgc, gpio);
129    unsigned long flags;
130
131    spin_lock_irqsave(&bgc->lock, flags);
132
133    if (val)
134        bgc->data |= mask;
135    else
136        bgc->data &= ~mask;
137
138    bgc->write_reg(bgc->reg_dat, bgc->data);
139
140    spin_unlock_irqrestore(&bgc->lock, flags);
141}
142
143static void bgpio_set_with_clear(struct gpio_chip *gc, unsigned int gpio,
144                 int val)
145{
146    struct bgpio_chip *bgc = to_bgpio_chip(gc);
147    unsigned long mask = bgc->pin2mask(bgc, gpio);
148
149    if (val)
150        bgc->write_reg(bgc->reg_set, mask);
151    else
152        bgc->write_reg(bgc->reg_clr, mask);
153}
154
155static void bgpio_set_set(struct gpio_chip *gc, unsigned int gpio, int val)
156{
157    struct bgpio_chip *bgc = to_bgpio_chip(gc);
158    unsigned long mask = bgc->pin2mask(bgc, gpio);
159    unsigned long flags;
160
161    spin_lock_irqsave(&bgc->lock, flags);
162
163    if (val)
164        bgc->data |= mask;
165    else
166        bgc->data &= ~mask;
167
168    bgc->write_reg(bgc->reg_set, bgc->data);
169
170    spin_unlock_irqrestore(&bgc->lock, flags);
171}
172
173static int bgpio_simple_dir_in(struct gpio_chip *gc, unsigned int gpio)
174{
175    return 0;
176}
177
178static int bgpio_simple_dir_out(struct gpio_chip *gc, unsigned int gpio,
179                int val)
180{
181    gc->set(gc, gpio, val);
182
183    return 0;
184}
185
186static int bgpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
187{
188    struct bgpio_chip *bgc = to_bgpio_chip(gc);
189    unsigned long flags;
190
191    spin_lock_irqsave(&bgc->lock, flags);
192
193    bgc->dir &= ~bgc->pin2mask(bgc, gpio);
194    bgc->write_reg(bgc->reg_dir, bgc->dir);
195
196    spin_unlock_irqrestore(&bgc->lock, flags);
197
198    return 0;
199}
200
201static int bgpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
202{
203    struct bgpio_chip *bgc = to_bgpio_chip(gc);
204    unsigned long flags;
205
206    gc->set(gc, gpio, val);
207
208    spin_lock_irqsave(&bgc->lock, flags);
209
210    bgc->dir |= bgc->pin2mask(bgc, gpio);
211    bgc->write_reg(bgc->reg_dir, bgc->dir);
212
213    spin_unlock_irqrestore(&bgc->lock, flags);
214
215    return 0;
216}
217
218static int bgpio_dir_in_inv(struct gpio_chip *gc, unsigned int gpio)
219{
220    struct bgpio_chip *bgc = to_bgpio_chip(gc);
221    unsigned long flags;
222
223    spin_lock_irqsave(&bgc->lock, flags);
224
225    bgc->dir |= bgc->pin2mask(bgc, gpio);
226    bgc->write_reg(bgc->reg_dir, bgc->dir);
227
228    spin_unlock_irqrestore(&bgc->lock, flags);
229
230    return 0;
231}
232
233static int bgpio_dir_out_inv(struct gpio_chip *gc, unsigned int gpio, int val)
234{
235    struct bgpio_chip *bgc = to_bgpio_chip(gc);
236    unsigned long flags;
237
238    gc->set(gc, gpio, val);
239
240    spin_lock_irqsave(&bgc->lock, flags);
241
242    bgc->dir &= ~bgc->pin2mask(bgc, gpio);
243    bgc->write_reg(bgc->reg_dir, bgc->dir);
244
245    spin_unlock_irqrestore(&bgc->lock, flags);
246
247    return 0;
248}
249
250static int bgpio_setup_accessors(struct device *dev,
251                 struct bgpio_chip *bgc,
252                 bool be)
253{
254
255    switch (bgc->bits) {
256    case 8:
257        bgc->read_reg = bgpio_read8;
258        bgc->write_reg = bgpio_write8;
259        break;
260    case 16:
261        bgc->read_reg = bgpio_read16;
262        bgc->write_reg = bgpio_write16;
263        break;
264    case 32:
265        bgc->read_reg = bgpio_read32;
266        bgc->write_reg = bgpio_write32;
267        break;
268#if BITS_PER_LONG >= 64
269    case 64:
270        bgc->read_reg = bgpio_read64;
271        bgc->write_reg = bgpio_write64;
272        break;
273#endif /* BITS_PER_LONG >= 64 */
274    default:
275        dev_err(dev, "unsupported data width %u bits\n", bgc->bits);
276        return -EINVAL;
277    }
278
279    bgc->pin2mask = be ? bgpio_pin2mask_be : bgpio_pin2mask;
280
281    return 0;
282}
283
284/*
285 * Create the device and allocate the resources. For setting GPIO's there are
286 * three supported configurations:
287 *
288 * - single input/output register resource (named "dat").
289 * - set/clear pair (named "set" and "clr").
290 * - single output register resource and single input resource ("set" and
291 * dat").
292 *
293 * For the single output register, this drives a 1 by setting a bit and a zero
294 * by clearing a bit. For the set clr pair, this drives a 1 by setting a bit
295 * in the set register and clears it by setting a bit in the clear register.
296 * The configuration is detected by which resources are present.
297 *
298 * For setting the GPIO direction, there are three supported configurations:
299 *
300 * - simple bidirection GPIO that requires no configuration.
301 * - an output direction register (named "dirout") where a 1 bit
302 * indicates the GPIO is an output.
303 * - an input direction register (named "dirin") where a 1 bit indicates
304 * the GPIO is an input.
305 */
306static int bgpio_setup_io(struct bgpio_chip *bgc,
307              void __iomem *dat,
308              void __iomem *set,
309              void __iomem *clr)
310{
311
312    bgc->reg_dat = dat;
313    if (!bgc->reg_dat)
314        return -EINVAL;
315
316    if (set && clr) {
317        bgc->reg_set = set;
318        bgc->reg_clr = clr;
319        bgc->gc.set = bgpio_set_with_clear;
320    } else if (set && !clr) {
321        bgc->reg_set = set;
322        bgc->gc.set = bgpio_set_set;
323    } else {
324        bgc->gc.set = bgpio_set;
325    }
326
327    bgc->gc.get = bgpio_get;
328
329    return 0;
330}
331
332static int bgpio_setup_direction(struct bgpio_chip *bgc,
333                 void __iomem *dirout,
334                 void __iomem *dirin)
335{
336    if (dirout && dirin) {
337        return -EINVAL;
338    } else if (dirout) {
339        bgc->reg_dir = dirout;
340        bgc->gc.direction_output = bgpio_dir_out;
341        bgc->gc.direction_input = bgpio_dir_in;
342    } else if (dirin) {
343        bgc->reg_dir = dirin;
344        bgc->gc.direction_output = bgpio_dir_out_inv;
345        bgc->gc.direction_input = bgpio_dir_in_inv;
346    } else {
347        bgc->gc.direction_output = bgpio_simple_dir_out;
348        bgc->gc.direction_input = bgpio_simple_dir_in;
349    }
350
351    return 0;
352}
353
354int bgpio_remove(struct bgpio_chip *bgc)
355{
356    int err = gpiochip_remove(&bgc->gc);
357
358    kfree(bgc);
359
360    return err;
361}
362EXPORT_SYMBOL_GPL(bgpio_remove);
363
364int bgpio_init(struct bgpio_chip *bgc, struct device *dev,
365           unsigned long sz, void __iomem *dat, void __iomem *set,
366           void __iomem *clr, void __iomem *dirout, void __iomem *dirin,
367           unsigned long flags)
368{
369    int ret;
370
371    if (!is_power_of_2(sz))
372        return -EINVAL;
373
374    bgc->bits = sz * 8;
375    if (bgc->bits > BITS_PER_LONG)
376        return -EINVAL;
377
378    spin_lock_init(&bgc->lock);
379    bgc->gc.dev = dev;
380    bgc->gc.label = dev_name(dev);
381    bgc->gc.base = -1;
382    bgc->gc.ngpio = bgc->bits;
383
384    ret = bgpio_setup_io(bgc, dat, set, clr);
385    if (ret)
386        return ret;
387
388    ret = bgpio_setup_accessors(dev, bgc, flags & BGPIOF_BIG_ENDIAN);
389    if (ret)
390        return ret;
391
392    ret = bgpio_setup_direction(bgc, dirout, dirin);
393    if (ret)
394        return ret;
395
396    bgc->data = bgc->read_reg(bgc->reg_dat);
397    if (bgc->gc.set == bgpio_set_set &&
398            !(flags & BGPIOF_UNREADABLE_REG_SET))
399        bgc->data = bgc->read_reg(bgc->reg_set);
400    if (bgc->reg_dir && !(flags & BGPIOF_UNREADABLE_REG_DIR))
401        bgc->dir = bgc->read_reg(bgc->reg_dir);
402
403    return ret;
404}
405EXPORT_SYMBOL_GPL(bgpio_init);
406
407#ifdef CONFIG_GPIO_GENERIC_PLATFORM
408
409static void __iomem *bgpio_map(struct platform_device *pdev,
410                   const char *name,
411                   resource_size_t sane_sz,
412                   int *err)
413{
414    struct device *dev = &pdev->dev;
415    struct resource *r;
416    resource_size_t start;
417    resource_size_t sz;
418    void __iomem *ret;
419
420    *err = 0;
421
422    r = platform_get_resource_byname(pdev, IORESOURCE_MEM, name);
423    if (!r)
424        return NULL;
425
426    sz = resource_size(r);
427    if (sz != sane_sz) {
428        *err = -EINVAL;
429        return NULL;
430    }
431
432    start = r->start;
433    if (!devm_request_mem_region(dev, start, sz, r->name)) {
434        *err = -EBUSY;
435        return NULL;
436    }
437
438    ret = devm_ioremap(dev, start, sz);
439    if (!ret) {
440        *err = -ENOMEM;
441        return NULL;
442    }
443
444    return ret;
445}
446
447static int __devinit bgpio_pdev_probe(struct platform_device *pdev)
448{
449    struct device *dev = &pdev->dev;
450    struct resource *r;
451    void __iomem *dat;
452    void __iomem *set;
453    void __iomem *clr;
454    void __iomem *dirout;
455    void __iomem *dirin;
456    unsigned long sz;
457    unsigned long flags = 0;
458    int err;
459    struct bgpio_chip *bgc;
460    struct bgpio_pdata *pdata = dev_get_platdata(dev);
461
462    r = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dat");
463    if (!r)
464        return -EINVAL;
465
466    sz = resource_size(r);
467
468    dat = bgpio_map(pdev, "dat", sz, &err);
469    if (!dat)
470        return err ? err : -EINVAL;
471
472    set = bgpio_map(pdev, "set", sz, &err);
473    if (err)
474        return err;
475
476    clr = bgpio_map(pdev, "clr", sz, &err);
477    if (err)
478        return err;
479
480    dirout = bgpio_map(pdev, "dirout", sz, &err);
481    if (err)
482        return err;
483
484    dirin = bgpio_map(pdev, "dirin", sz, &err);
485    if (err)
486        return err;
487
488    if (!strcmp(platform_get_device_id(pdev)->name, "basic-mmio-gpio-be"))
489        flags |= BGPIOF_BIG_ENDIAN;
490
491    bgc = devm_kzalloc(&pdev->dev, sizeof(*bgc), GFP_KERNEL);
492    if (!bgc)
493        return -ENOMEM;
494
495    err = bgpio_init(bgc, dev, sz, dat, set, clr, dirout, dirin, flags);
496    if (err)
497        return err;
498
499    if (pdata) {
500        bgc->gc.base = pdata->base;
501        if (pdata->ngpio > 0)
502            bgc->gc.ngpio = pdata->ngpio;
503    }
504
505    platform_set_drvdata(pdev, bgc);
506
507    return gpiochip_add(&bgc->gc);
508}
509
510static int __devexit bgpio_pdev_remove(struct platform_device *pdev)
511{
512    struct bgpio_chip *bgc = platform_get_drvdata(pdev);
513
514    return bgpio_remove(bgc);
515}
516
517static const struct platform_device_id bgpio_id_table[] = {
518    { "basic-mmio-gpio", },
519    { "basic-mmio-gpio-be", },
520    {},
521};
522MODULE_DEVICE_TABLE(platform, bgpio_id_table);
523
524static struct platform_driver bgpio_driver = {
525    .driver = {
526        .name = "basic-mmio-gpio",
527    },
528    .id_table = bgpio_id_table,
529    .probe = bgpio_pdev_probe,
530    .remove = __devexit_p(bgpio_pdev_remove),
531};
532
533module_platform_driver(bgpio_driver);
534
535#endif /* CONFIG_GPIO_GENERIC_PLATFORM */
536
537MODULE_DESCRIPTION("Driver for basic memory-mapped GPIO controllers");
538MODULE_AUTHOR("Anton Vorontsov <cbouatmailru@gmail.com>");
539MODULE_LICENSE("GPL");
540

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