Merge branch 'r6040-next'
[linux/fpc-iii.git] / drivers / gpio / gpio-pcf857x.c
blob169c09aa33c85b7505c912d31b8176c18a81fcce
1 /*
2 * Driver for pcf857x, pca857x, and pca967x I2C GPIO expanders
4 * Copyright (C) 2007 David Brownell
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21 #include <linux/gpio.h>
22 #include <linux/i2c.h>
23 #include <linux/i2c/pcf857x.h>
24 #include <linux/interrupt.h>
25 #include <linux/irq.h>
26 #include <linux/irqdomain.h>
27 #include <linux/kernel.h>
28 #include <linux/module.h>
29 #include <linux/of.h>
30 #include <linux/of_device.h>
31 #include <linux/slab.h>
32 #include <linux/spinlock.h>
35 static const struct i2c_device_id pcf857x_id[] = {
36 { "pcf8574", 8 },
37 { "pcf8574a", 8 },
38 { "pca8574", 8 },
39 { "pca9670", 8 },
40 { "pca9672", 8 },
41 { "pca9674", 8 },
42 { "pcf8575", 16 },
43 { "pca8575", 16 },
44 { "pca9671", 16 },
45 { "pca9673", 16 },
46 { "pca9675", 16 },
47 { "max7328", 8 },
48 { "max7329", 8 },
49 { "tca9554", 8 },
50 { }
52 MODULE_DEVICE_TABLE(i2c, pcf857x_id);
54 #ifdef CONFIG_OF
55 static const struct of_device_id pcf857x_of_table[] = {
56 { .compatible = "nxp,pcf8574" },
57 { .compatible = "nxp,pcf8574a" },
58 { .compatible = "nxp,pca8574" },
59 { .compatible = "nxp,pca9670" },
60 { .compatible = "nxp,pca9672" },
61 { .compatible = "nxp,pca9674" },
62 { .compatible = "nxp,pcf8575" },
63 { .compatible = "nxp,pca8575" },
64 { .compatible = "nxp,pca9671" },
65 { .compatible = "nxp,pca9673" },
66 { .compatible = "nxp,pca9675" },
67 { .compatible = "maxim,max7328" },
68 { .compatible = "maxim,max7329" },
69 { .compatible = "ti,tca9554" },
70 { }
72 MODULE_DEVICE_TABLE(of, pcf857x_of_table);
73 #endif
76 * The pcf857x, pca857x, and pca967x chips only expose one read and one
77 * write register. Writing a "one" bit (to match the reset state) lets
78 * that pin be used as an input; it's not an open-drain model, but acts
79 * a bit like one. This is described as "quasi-bidirectional"; read the
80 * chip documentation for details.
82 * Many other I2C GPIO expander chips (like the pca953x models) have
83 * more complex register models and more conventional circuitry using
84 * push/pull drivers. They often use the same 0x20..0x27 addresses as
85 * pcf857x parts, making the "legacy" I2C driver model problematic.
87 struct pcf857x {
88 struct gpio_chip chip;
89 struct i2c_client *client;
90 struct mutex lock; /* protect 'out' */
91 unsigned out; /* software latch */
92 unsigned status; /* current status */
93 unsigned int irq_parent;
94 unsigned irq_enabled; /* enabled irqs */
96 int (*write)(struct i2c_client *client, unsigned data);
97 int (*read)(struct i2c_client *client);
100 /*-------------------------------------------------------------------------*/
102 /* Talk to 8-bit I/O expander */
104 static int i2c_write_le8(struct i2c_client *client, unsigned data)
106 return i2c_smbus_write_byte(client, data);
109 static int i2c_read_le8(struct i2c_client *client)
111 return (int)i2c_smbus_read_byte(client);
114 /* Talk to 16-bit I/O expander */
116 static int i2c_write_le16(struct i2c_client *client, unsigned word)
118 u8 buf[2] = { word & 0xff, word >> 8, };
119 int status;
121 status = i2c_master_send(client, buf, 2);
122 return (status < 0) ? status : 0;
125 static int i2c_read_le16(struct i2c_client *client)
127 u8 buf[2];
128 int status;
130 status = i2c_master_recv(client, buf, 2);
131 if (status < 0)
132 return status;
133 return (buf[1] << 8) | buf[0];
136 /*-------------------------------------------------------------------------*/
138 static int pcf857x_input(struct gpio_chip *chip, unsigned offset)
140 struct pcf857x *gpio = gpiochip_get_data(chip);
141 int status;
143 mutex_lock(&gpio->lock);
144 gpio->out |= (1 << offset);
145 status = gpio->write(gpio->client, gpio->out);
146 mutex_unlock(&gpio->lock);
148 return status;
151 static int pcf857x_get(struct gpio_chip *chip, unsigned offset)
153 struct pcf857x *gpio = gpiochip_get_data(chip);
154 int value;
156 value = gpio->read(gpio->client);
157 return (value < 0) ? value : !!(value & (1 << offset));
160 static int pcf857x_output(struct gpio_chip *chip, unsigned offset, int value)
162 struct pcf857x *gpio = gpiochip_get_data(chip);
163 unsigned bit = 1 << offset;
164 int status;
166 mutex_lock(&gpio->lock);
167 if (value)
168 gpio->out |= bit;
169 else
170 gpio->out &= ~bit;
171 status = gpio->write(gpio->client, gpio->out);
172 mutex_unlock(&gpio->lock);
174 return status;
177 static void pcf857x_set(struct gpio_chip *chip, unsigned offset, int value)
179 pcf857x_output(chip, offset, value);
182 /*-------------------------------------------------------------------------*/
184 static irqreturn_t pcf857x_irq(int irq, void *data)
186 struct pcf857x *gpio = data;
187 unsigned long change, i, status;
189 status = gpio->read(gpio->client);
192 * call the interrupt handler iff gpio is used as
193 * interrupt source, just to avoid bad irqs
195 mutex_lock(&gpio->lock);
196 change = (gpio->status ^ status) & gpio->irq_enabled;
197 gpio->status = status;
198 mutex_unlock(&gpio->lock);
200 for_each_set_bit(i, &change, gpio->chip.ngpio)
201 handle_nested_irq(irq_find_mapping(gpio->chip.irqdomain, i));
203 return IRQ_HANDLED;
207 * NOP functions
209 static void noop(struct irq_data *data) { }
211 static int pcf857x_irq_set_wake(struct irq_data *data, unsigned int on)
213 struct pcf857x *gpio = irq_data_get_irq_chip_data(data);
215 int error = 0;
217 if (gpio->irq_parent) {
218 error = irq_set_irq_wake(gpio->irq_parent, on);
219 if (error) {
220 dev_dbg(&gpio->client->dev,
221 "irq %u doesn't support irq_set_wake\n",
222 gpio->irq_parent);
223 gpio->irq_parent = 0;
226 return error;
229 static void pcf857x_irq_enable(struct irq_data *data)
231 struct pcf857x *gpio = irq_data_get_irq_chip_data(data);
233 gpio->irq_enabled |= (1 << data->hwirq);
236 static void pcf857x_irq_disable(struct irq_data *data)
238 struct pcf857x *gpio = irq_data_get_irq_chip_data(data);
240 gpio->irq_enabled &= ~(1 << data->hwirq);
243 static void pcf857x_irq_bus_lock(struct irq_data *data)
245 struct pcf857x *gpio = irq_data_get_irq_chip_data(data);
247 mutex_lock(&gpio->lock);
250 static void pcf857x_irq_bus_sync_unlock(struct irq_data *data)
252 struct pcf857x *gpio = irq_data_get_irq_chip_data(data);
254 mutex_unlock(&gpio->lock);
257 static struct irq_chip pcf857x_irq_chip = {
258 .name = "pcf857x",
259 .irq_enable = pcf857x_irq_enable,
260 .irq_disable = pcf857x_irq_disable,
261 .irq_ack = noop,
262 .irq_mask = noop,
263 .irq_unmask = noop,
264 .irq_set_wake = pcf857x_irq_set_wake,
265 .irq_bus_lock = pcf857x_irq_bus_lock,
266 .irq_bus_sync_unlock = pcf857x_irq_bus_sync_unlock,
269 /*-------------------------------------------------------------------------*/
271 static int pcf857x_probe(struct i2c_client *client,
272 const struct i2c_device_id *id)
274 struct pcf857x_platform_data *pdata = dev_get_platdata(&client->dev);
275 struct device_node *np = client->dev.of_node;
276 struct pcf857x *gpio;
277 unsigned int n_latch = 0;
278 int status;
280 if (IS_ENABLED(CONFIG_OF) && np)
281 of_property_read_u32(np, "lines-initial-states", &n_latch);
282 else if (pdata)
283 n_latch = pdata->n_latch;
284 else
285 dev_dbg(&client->dev, "no platform data\n");
287 /* Allocate, initialize, and register this gpio_chip. */
288 gpio = devm_kzalloc(&client->dev, sizeof(*gpio), GFP_KERNEL);
289 if (!gpio)
290 return -ENOMEM;
292 mutex_init(&gpio->lock);
294 gpio->chip.base = pdata ? pdata->gpio_base : -1;
295 gpio->chip.can_sleep = true;
296 gpio->chip.parent = &client->dev;
297 gpio->chip.owner = THIS_MODULE;
298 gpio->chip.get = pcf857x_get;
299 gpio->chip.set = pcf857x_set;
300 gpio->chip.direction_input = pcf857x_input;
301 gpio->chip.direction_output = pcf857x_output;
302 gpio->chip.ngpio = id->driver_data;
304 /* NOTE: the OnSemi jlc1562b is also largely compatible with
305 * these parts, notably for output. It has a low-resolution
306 * DAC instead of pin change IRQs; and its inputs can be the
307 * result of comparators.
310 /* 8574 addresses are 0x20..0x27; 8574a uses 0x38..0x3f;
311 * 9670, 9672, 9764, and 9764a use quite a variety.
313 * NOTE: we don't distinguish here between *4 and *4a parts.
315 if (gpio->chip.ngpio == 8) {
316 gpio->write = i2c_write_le8;
317 gpio->read = i2c_read_le8;
319 if (!i2c_check_functionality(client->adapter,
320 I2C_FUNC_SMBUS_BYTE))
321 status = -EIO;
323 /* fail if there's no chip present */
324 else
325 status = i2c_smbus_read_byte(client);
327 /* '75/'75c addresses are 0x20..0x27, just like the '74;
328 * the '75c doesn't have a current source pulling high.
329 * 9671, 9673, and 9765 use quite a variety of addresses.
331 * NOTE: we don't distinguish here between '75 and '75c parts.
333 } else if (gpio->chip.ngpio == 16) {
334 gpio->write = i2c_write_le16;
335 gpio->read = i2c_read_le16;
337 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
338 status = -EIO;
340 /* fail if there's no chip present */
341 else
342 status = i2c_read_le16(client);
344 } else {
345 dev_dbg(&client->dev, "unsupported number of gpios\n");
346 status = -EINVAL;
349 if (status < 0)
350 goto fail;
352 gpio->chip.label = client->name;
354 gpio->client = client;
355 i2c_set_clientdata(client, gpio);
357 /* NOTE: these chips have strange "quasi-bidirectional" I/O pins.
358 * We can't actually know whether a pin is configured (a) as output
359 * and driving the signal low, or (b) as input and reporting a low
360 * value ... without knowing the last value written since the chip
361 * came out of reset (if any). We can't read the latched output.
363 * In short, the only reliable solution for setting up pin direction
364 * is to do it explicitly. The setup() method can do that, but it
365 * may cause transient glitching since it can't know the last value
366 * written (some pins may need to be driven low).
368 * Using n_latch avoids that trouble. When left initialized to zero,
369 * our software copy of the "latch" then matches the chip's all-ones
370 * reset state. Otherwise it flags pins to be driven low.
372 gpio->out = ~n_latch;
373 gpio->status = gpio->out;
375 status = devm_gpiochip_add_data(&client->dev, &gpio->chip, gpio);
376 if (status < 0)
377 goto fail;
379 /* Enable irqchip if we have an interrupt */
380 if (client->irq) {
381 status = gpiochip_irqchip_add(&gpio->chip, &pcf857x_irq_chip,
382 0, handle_level_irq,
383 IRQ_TYPE_NONE);
384 if (status) {
385 dev_err(&client->dev, "cannot add irqchip\n");
386 goto fail;
389 status = devm_request_threaded_irq(&client->dev, client->irq,
390 NULL, pcf857x_irq, IRQF_ONESHOT |
391 IRQF_TRIGGER_FALLING | IRQF_SHARED,
392 dev_name(&client->dev), gpio);
393 if (status)
394 goto fail;
396 gpiochip_set_chained_irqchip(&gpio->chip, &pcf857x_irq_chip,
397 client->irq, NULL);
398 gpio->irq_parent = client->irq;
401 /* Let platform code set up the GPIOs and their users.
402 * Now is the first time anyone could use them.
404 if (pdata && pdata->setup) {
405 status = pdata->setup(client,
406 gpio->chip.base, gpio->chip.ngpio,
407 pdata->context);
408 if (status < 0)
409 dev_warn(&client->dev, "setup --> %d\n", status);
412 dev_info(&client->dev, "probed\n");
414 return 0;
416 fail:
417 dev_dbg(&client->dev, "probe error %d for '%s'\n", status,
418 client->name);
420 return status;
423 static int pcf857x_remove(struct i2c_client *client)
425 struct pcf857x_platform_data *pdata = dev_get_platdata(&client->dev);
426 struct pcf857x *gpio = i2c_get_clientdata(client);
427 int status = 0;
429 if (pdata && pdata->teardown) {
430 status = pdata->teardown(client,
431 gpio->chip.base, gpio->chip.ngpio,
432 pdata->context);
433 if (status < 0) {
434 dev_err(&client->dev, "%s --> %d\n",
435 "teardown", status);
436 return status;
440 return status;
443 static struct i2c_driver pcf857x_driver = {
444 .driver = {
445 .name = "pcf857x",
446 .of_match_table = of_match_ptr(pcf857x_of_table),
448 .probe = pcf857x_probe,
449 .remove = pcf857x_remove,
450 .id_table = pcf857x_id,
453 static int __init pcf857x_init(void)
455 return i2c_add_driver(&pcf857x_driver);
457 /* register after i2c postcore initcall and before
458 * subsys initcalls that may rely on these GPIOs
460 subsys_initcall(pcf857x_init);
462 static void __exit pcf857x_exit(void)
464 i2c_del_driver(&pcf857x_driver);
466 module_exit(pcf857x_exit);
468 MODULE_LICENSE("GPL");
469 MODULE_AUTHOR("David Brownell");