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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Driver for pcf857x, pca857x, and pca967x I2C GPIO expanders
4 *
5 * Copyright (C) 2007 David Brownell
6 */
7
8#include <linux/gpio/driver.h>
9#include <linux/i2c.h>
10#include <linux/platform_data/pcf857x.h>
11#include <linux/interrupt.h>
12#include <linux/irq.h>
13#include <linux/irqdomain.h>
14#include <linux/kernel.h>
15#include <linux/module.h>
16#include <linux/of.h>
17#include <linux/of_device.h>
18#include <linux/slab.h>
19#include <linux/spinlock.h>
20
21
22static const struct i2c_device_id pcf857x_id[] = {
23 { "pcf8574", 8 },
24 { "pcf8574a", 8 },
25 { "pca8574", 8 },
26 { "pca9670", 8 },
27 { "pca9672", 8 },
28 { "pca9674", 8 },
29 { "pcf8575", 16 },
30 { "pca8575", 16 },
31 { "pca9671", 16 },
32 { "pca9673", 16 },
33 { "pca9675", 16 },
34 { "max7328", 8 },
35 { "max7329", 8 },
36 { }
37};
38MODULE_DEVICE_TABLE(i2c, pcf857x_id);
39
40#ifdef CONFIG_OF
41static const struct of_device_id pcf857x_of_table[] = {
42 { .compatible = "nxp,pcf8574" },
43 { .compatible = "nxp,pcf8574a" },
44 { .compatible = "nxp,pca8574" },
45 { .compatible = "nxp,pca9670" },
46 { .compatible = "nxp,pca9672" },
47 { .compatible = "nxp,pca9674" },
48 { .compatible = "nxp,pcf8575" },
49 { .compatible = "nxp,pca8575" },
50 { .compatible = "nxp,pca9671" },
51 { .compatible = "nxp,pca9673" },
52 { .compatible = "nxp,pca9675" },
53 { .compatible = "maxim,max7328" },
54 { .compatible = "maxim,max7329" },
55 { }
56};
57MODULE_DEVICE_TABLE(of, pcf857x_of_table);
58#endif
59
60/*
61 * The pcf857x, pca857x, and pca967x chips only expose one read and one
62 * write register. Writing a "one" bit (to match the reset state) lets
63 * that pin be used as an input; it's not an open-drain model, but acts
64 * a bit like one. This is described as "quasi-bidirectional"; read the
65 * chip documentation for details.
66 *
67 * Many other I2C GPIO expander chips (like the pca953x models) have
68 * more complex register models and more conventional circuitry using
69 * push/pull drivers. They often use the same 0x20..0x27 addresses as
70 * pcf857x parts, making the "legacy" I2C driver model problematic.
71 */
72struct pcf857x {
73 struct gpio_chip chip;
74 struct irq_chip irqchip;
75 struct i2c_client *client;
76 struct mutex lock; /* protect 'out' */
77 unsigned out; /* software latch */
78 unsigned status; /* current status */
79 unsigned irq_enabled; /* enabled irqs */
80
81 int (*write)(struct i2c_client *client, unsigned data);
82 int (*read)(struct i2c_client *client);
83};
84
85/*-------------------------------------------------------------------------*/
86
87/* Talk to 8-bit I/O expander */
88
89static int i2c_write_le8(struct i2c_client *client, unsigned data)
90{
91 return i2c_smbus_write_byte(client, data);
92}
93
94static int i2c_read_le8(struct i2c_client *client)
95{
96 return (int)i2c_smbus_read_byte(client);
97}
98
99/* Talk to 16-bit I/O expander */
100
101static int i2c_write_le16(struct i2c_client *client, unsigned word)
102{
103 u8 buf[2] = { word & 0xff, word >> 8, };
104 int status;
105
106 status = i2c_master_send(client, buf, 2);
107 return (status < 0) ? status : 0;
108}
109
110static int i2c_read_le16(struct i2c_client *client)
111{
112 u8 buf[2];
113 int status;
114
115 status = i2c_master_recv(client, buf, 2);
116 if (status < 0)
117 return status;
118 return (buf[1] << 8) | buf[0];
119}
120
121/*-------------------------------------------------------------------------*/
122
123static int pcf857x_input(struct gpio_chip *chip, unsigned offset)
124{
125 struct pcf857x *gpio = gpiochip_get_data(chip);
126 int status;
127
128 mutex_lock(&gpio->lock);
129 gpio->out |= (1 << offset);
130 status = gpio->write(gpio->client, gpio->out);
131 mutex_unlock(&gpio->lock);
132
133 return status;
134}
135
136static int pcf857x_get(struct gpio_chip *chip, unsigned offset)
137{
138 struct pcf857x *gpio = gpiochip_get_data(chip);
139 int value;
140
141 value = gpio->read(gpio->client);
142 return (value < 0) ? value : !!(value & (1 << offset));
143}
144
145static int pcf857x_output(struct gpio_chip *chip, unsigned offset, int value)
146{
147 struct pcf857x *gpio = gpiochip_get_data(chip);
148 unsigned bit = 1 << offset;
149 int status;
150
151 mutex_lock(&gpio->lock);
152 if (value)
153 gpio->out |= bit;
154 else
155 gpio->out &= ~bit;
156 status = gpio->write(gpio->client, gpio->out);
157 mutex_unlock(&gpio->lock);
158
159 return status;
160}
161
162static void pcf857x_set(struct gpio_chip *chip, unsigned offset, int value)
163{
164 pcf857x_output(chip, offset, value);
165}
166
167/*-------------------------------------------------------------------------*/
168
169static irqreturn_t pcf857x_irq(int irq, void *data)
170{
171 struct pcf857x *gpio = data;
172 unsigned long change, i, status;
173
174 status = gpio->read(gpio->client);
175
176 /*
177 * call the interrupt handler iff gpio is used as
178 * interrupt source, just to avoid bad irqs
179 */
180 mutex_lock(&gpio->lock);
181 change = (gpio->status ^ status) & gpio->irq_enabled;
182 gpio->status = status;
183 mutex_unlock(&gpio->lock);
184
185 for_each_set_bit(i, &change, gpio->chip.ngpio)
186 handle_nested_irq(irq_find_mapping(gpio->chip.irq.domain, i));
187
188 return IRQ_HANDLED;
189}
190
191/*
192 * NOP functions
193 */
194static void noop(struct irq_data *data) { }
195
196static int pcf857x_irq_set_wake(struct irq_data *data, unsigned int on)
197{
198 struct pcf857x *gpio = irq_data_get_irq_chip_data(data);
199
200 return irq_set_irq_wake(gpio->client->irq, on);
201}
202
203static void pcf857x_irq_enable(struct irq_data *data)
204{
205 struct pcf857x *gpio = irq_data_get_irq_chip_data(data);
206
207 gpio->irq_enabled |= (1 << data->hwirq);
208}
209
210static void pcf857x_irq_disable(struct irq_data *data)
211{
212 struct pcf857x *gpio = irq_data_get_irq_chip_data(data);
213
214 gpio->irq_enabled &= ~(1 << data->hwirq);
215}
216
217static void pcf857x_irq_bus_lock(struct irq_data *data)
218{
219 struct pcf857x *gpio = irq_data_get_irq_chip_data(data);
220
221 mutex_lock(&gpio->lock);
222}
223
224static void pcf857x_irq_bus_sync_unlock(struct irq_data *data)
225{
226 struct pcf857x *gpio = irq_data_get_irq_chip_data(data);
227
228 mutex_unlock(&gpio->lock);
229}
230
231/*-------------------------------------------------------------------------*/
232
233static int pcf857x_probe(struct i2c_client *client,
234 const struct i2c_device_id *id)
235{
236 struct pcf857x_platform_data *pdata = dev_get_platdata(&client->dev);
237 struct device_node *np = client->dev.of_node;
238 struct pcf857x *gpio;
239 unsigned int n_latch = 0;
240 int status;
241
242 if (IS_ENABLED(CONFIG_OF) && np)
243 of_property_read_u32(np, "lines-initial-states", &n_latch);
244 else if (pdata)
245 n_latch = pdata->n_latch;
246 else
247 dev_dbg(&client->dev, "no platform data\n");
248
249 /* Allocate, initialize, and register this gpio_chip. */
250 gpio = devm_kzalloc(&client->dev, sizeof(*gpio), GFP_KERNEL);
251 if (!gpio)
252 return -ENOMEM;
253
254 mutex_init(&gpio->lock);
255
256 gpio->chip.base = pdata ? pdata->gpio_base : -1;
257 gpio->chip.can_sleep = true;
258 gpio->chip.parent = &client->dev;
259 gpio->chip.owner = THIS_MODULE;
260 gpio->chip.get = pcf857x_get;
261 gpio->chip.set = pcf857x_set;
262 gpio->chip.direction_input = pcf857x_input;
263 gpio->chip.direction_output = pcf857x_output;
264 gpio->chip.ngpio = id->driver_data;
265
266 /* NOTE: the OnSemi jlc1562b is also largely compatible with
267 * these parts, notably for output. It has a low-resolution
268 * DAC instead of pin change IRQs; and its inputs can be the
269 * result of comparators.
270 */
271
272 /* 8574 addresses are 0x20..0x27; 8574a uses 0x38..0x3f;
273 * 9670, 9672, 9764, and 9764a use quite a variety.
274 *
275 * NOTE: we don't distinguish here between *4 and *4a parts.
276 */
277 if (gpio->chip.ngpio == 8) {
278 gpio->write = i2c_write_le8;
279 gpio->read = i2c_read_le8;
280
281 if (!i2c_check_functionality(client->adapter,
282 I2C_FUNC_SMBUS_BYTE))
283 status = -EIO;
284
285 /* fail if there's no chip present */
286 else
287 status = i2c_smbus_read_byte(client);
288
289 /* '75/'75c addresses are 0x20..0x27, just like the '74;
290 * the '75c doesn't have a current source pulling high.
291 * 9671, 9673, and 9765 use quite a variety of addresses.
292 *
293 * NOTE: we don't distinguish here between '75 and '75c parts.
294 */
295 } else if (gpio->chip.ngpio == 16) {
296 gpio->write = i2c_write_le16;
297 gpio->read = i2c_read_le16;
298
299 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
300 status = -EIO;
301
302 /* fail if there's no chip present */
303 else
304 status = i2c_read_le16(client);
305
306 } else {
307 dev_dbg(&client->dev, "unsupported number of gpios\n");
308 status = -EINVAL;
309 }
310
311 if (status < 0)
312 goto fail;
313
314 gpio->chip.label = client->name;
315
316 gpio->client = client;
317 i2c_set_clientdata(client, gpio);
318
319 /* NOTE: these chips have strange "quasi-bidirectional" I/O pins.
320 * We can't actually know whether a pin is configured (a) as output
321 * and driving the signal low, or (b) as input and reporting a low
322 * value ... without knowing the last value written since the chip
323 * came out of reset (if any). We can't read the latched output.
324 *
325 * In short, the only reliable solution for setting up pin direction
326 * is to do it explicitly. The setup() method can do that, but it
327 * may cause transient glitching since it can't know the last value
328 * written (some pins may need to be driven low).
329 *
330 * Using n_latch avoids that trouble. When left initialized to zero,
331 * our software copy of the "latch" then matches the chip's all-ones
332 * reset state. Otherwise it flags pins to be driven low.
333 */
334 gpio->out = ~n_latch;
335 gpio->status = gpio->out;
336
337 /* Enable irqchip if we have an interrupt */
338 if (client->irq) {
339 struct gpio_irq_chip *girq;
340
341 gpio->irqchip.name = "pcf857x";
342 gpio->irqchip.irq_enable = pcf857x_irq_enable;
343 gpio->irqchip.irq_disable = pcf857x_irq_disable;
344 gpio->irqchip.irq_ack = noop;
345 gpio->irqchip.irq_mask = noop;
346 gpio->irqchip.irq_unmask = noop;
347 gpio->irqchip.irq_set_wake = pcf857x_irq_set_wake;
348 gpio->irqchip.irq_bus_lock = pcf857x_irq_bus_lock;
349 gpio->irqchip.irq_bus_sync_unlock = pcf857x_irq_bus_sync_unlock;
350
351 status = devm_request_threaded_irq(&client->dev, client->irq,
352 NULL, pcf857x_irq, IRQF_ONESHOT |
353 IRQF_TRIGGER_FALLING | IRQF_SHARED,
354 dev_name(&client->dev), gpio);
355 if (status)
356 goto fail;
357
358 girq = &gpio->chip.irq;
359 girq->chip = &gpio->irqchip;
360 /* This will let us handle the parent IRQ in the driver */
361 girq->parent_handler = NULL;
362 girq->num_parents = 0;
363 girq->parents = NULL;
364 girq->default_type = IRQ_TYPE_NONE;
365 girq->handler = handle_level_irq;
366 girq->threaded = true;
367 }
368
369 status = devm_gpiochip_add_data(&client->dev, &gpio->chip, gpio);
370 if (status < 0)
371 goto fail;
372
373 /* Let platform code set up the GPIOs and their users.
374 * Now is the first time anyone could use them.
375 */
376 if (pdata && pdata->setup) {
377 status = pdata->setup(client,
378 gpio->chip.base, gpio->chip.ngpio,
379 pdata->context);
380 if (status < 0)
381 dev_warn(&client->dev, "setup --> %d\n", status);
382 }
383
384 dev_info(&client->dev, "probed\n");
385
386 return 0;
387
388fail:
389 dev_dbg(&client->dev, "probe error %d for '%s'\n", status,
390 client->name);
391
392 return status;
393}
394
395static int pcf857x_remove(struct i2c_client *client)
396{
397 struct pcf857x_platform_data *pdata = dev_get_platdata(&client->dev);
398 struct pcf857x *gpio = i2c_get_clientdata(client);
399 int status = 0;
400
401 if (pdata && pdata->teardown) {
402 status = pdata->teardown(client,
403 gpio->chip.base, gpio->chip.ngpio,
404 pdata->context);
405 if (status < 0) {
406 dev_err(&client->dev, "%s --> %d\n",
407 "teardown", status);
408 return status;
409 }
410 }
411
412 return status;
413}
414
415static void pcf857x_shutdown(struct i2c_client *client)
416{
417 struct pcf857x *gpio = i2c_get_clientdata(client);
418
419 /* Drive all the I/O lines high */
420 gpio->write(gpio->client, BIT(gpio->chip.ngpio) - 1);
421}
422
423static struct i2c_driver pcf857x_driver = {
424 .driver = {
425 .name = "pcf857x",
426 .of_match_table = of_match_ptr(pcf857x_of_table),
427 },
428 .probe = pcf857x_probe,
429 .remove = pcf857x_remove,
430 .shutdown = pcf857x_shutdown,
431 .id_table = pcf857x_id,
432};
433
434static int __init pcf857x_init(void)
435{
436 return i2c_add_driver(&pcf857x_driver);
437}
438/* register after i2c postcore initcall and before
439 * subsys initcalls that may rely on these GPIOs
440 */
441subsys_initcall(pcf857x_init);
442
443static void __exit pcf857x_exit(void)
444{
445 i2c_del_driver(&pcf857x_driver);
446}
447module_exit(pcf857x_exit);
448
449MODULE_LICENSE("GPL");
450MODULE_AUTHOR("David Brownell");
1/*
2 * Driver for pcf857x, pca857x, and pca967x I2C GPIO expanders
3 *
4 * Copyright (C) 2007 David Brownell
5 *
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.
10 *
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.
15 *
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.
19 */
20
21#include <linux/gpio.h>
22#include <linux/i2c.h>
23#include <linux/platform_data/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>
33
34
35static 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 { }
50};
51MODULE_DEVICE_TABLE(i2c, pcf857x_id);
52
53#ifdef CONFIG_OF
54static const struct of_device_id pcf857x_of_table[] = {
55 { .compatible = "nxp,pcf8574" },
56 { .compatible = "nxp,pcf8574a" },
57 { .compatible = "nxp,pca8574" },
58 { .compatible = "nxp,pca9670" },
59 { .compatible = "nxp,pca9672" },
60 { .compatible = "nxp,pca9674" },
61 { .compatible = "nxp,pcf8575" },
62 { .compatible = "nxp,pca8575" },
63 { .compatible = "nxp,pca9671" },
64 { .compatible = "nxp,pca9673" },
65 { .compatible = "nxp,pca9675" },
66 { .compatible = "maxim,max7328" },
67 { .compatible = "maxim,max7329" },
68 { }
69};
70MODULE_DEVICE_TABLE(of, pcf857x_of_table);
71#endif
72
73/*
74 * The pcf857x, pca857x, and pca967x chips only expose one read and one
75 * write register. Writing a "one" bit (to match the reset state) lets
76 * that pin be used as an input; it's not an open-drain model, but acts
77 * a bit like one. This is described as "quasi-bidirectional"; read the
78 * chip documentation for details.
79 *
80 * Many other I2C GPIO expander chips (like the pca953x models) have
81 * more complex register models and more conventional circuitry using
82 * push/pull drivers. They often use the same 0x20..0x27 addresses as
83 * pcf857x parts, making the "legacy" I2C driver model problematic.
84 */
85struct pcf857x {
86 struct gpio_chip chip;
87 struct i2c_client *client;
88 struct mutex lock; /* protect 'out' */
89 unsigned out; /* software latch */
90 unsigned status; /* current status */
91 unsigned int irq_parent;
92 unsigned irq_enabled; /* enabled irqs */
93
94 int (*write)(struct i2c_client *client, unsigned data);
95 int (*read)(struct i2c_client *client);
96};
97
98/*-------------------------------------------------------------------------*/
99
100/* Talk to 8-bit I/O expander */
101
102static int i2c_write_le8(struct i2c_client *client, unsigned data)
103{
104 return i2c_smbus_write_byte(client, data);
105}
106
107static int i2c_read_le8(struct i2c_client *client)
108{
109 return (int)i2c_smbus_read_byte(client);
110}
111
112/* Talk to 16-bit I/O expander */
113
114static int i2c_write_le16(struct i2c_client *client, unsigned word)
115{
116 u8 buf[2] = { word & 0xff, word >> 8, };
117 int status;
118
119 status = i2c_master_send(client, buf, 2);
120 return (status < 0) ? status : 0;
121}
122
123static int i2c_read_le16(struct i2c_client *client)
124{
125 u8 buf[2];
126 int status;
127
128 status = i2c_master_recv(client, buf, 2);
129 if (status < 0)
130 return status;
131 return (buf[1] << 8) | buf[0];
132}
133
134/*-------------------------------------------------------------------------*/
135
136static int pcf857x_input(struct gpio_chip *chip, unsigned offset)
137{
138 struct pcf857x *gpio = gpiochip_get_data(chip);
139 int status;
140
141 mutex_lock(&gpio->lock);
142 gpio->out |= (1 << offset);
143 status = gpio->write(gpio->client, gpio->out);
144 mutex_unlock(&gpio->lock);
145
146 return status;
147}
148
149static int pcf857x_get(struct gpio_chip *chip, unsigned offset)
150{
151 struct pcf857x *gpio = gpiochip_get_data(chip);
152 int value;
153
154 value = gpio->read(gpio->client);
155 return (value < 0) ? value : !!(value & (1 << offset));
156}
157
158static int pcf857x_output(struct gpio_chip *chip, unsigned offset, int value)
159{
160 struct pcf857x *gpio = gpiochip_get_data(chip);
161 unsigned bit = 1 << offset;
162 int status;
163
164 mutex_lock(&gpio->lock);
165 if (value)
166 gpio->out |= bit;
167 else
168 gpio->out &= ~bit;
169 status = gpio->write(gpio->client, gpio->out);
170 mutex_unlock(&gpio->lock);
171
172 return status;
173}
174
175static void pcf857x_set(struct gpio_chip *chip, unsigned offset, int value)
176{
177 pcf857x_output(chip, offset, value);
178}
179
180/*-------------------------------------------------------------------------*/
181
182static irqreturn_t pcf857x_irq(int irq, void *data)
183{
184 struct pcf857x *gpio = data;
185 unsigned long change, i, status;
186
187 status = gpio->read(gpio->client);
188
189 /*
190 * call the interrupt handler iff gpio is used as
191 * interrupt source, just to avoid bad irqs
192 */
193 mutex_lock(&gpio->lock);
194 change = (gpio->status ^ status) & gpio->irq_enabled;
195 gpio->status = status;
196 mutex_unlock(&gpio->lock);
197
198 for_each_set_bit(i, &change, gpio->chip.ngpio)
199 handle_nested_irq(irq_find_mapping(gpio->chip.irq.domain, i));
200
201 return IRQ_HANDLED;
202}
203
204/*
205 * NOP functions
206 */
207static void noop(struct irq_data *data) { }
208
209static int pcf857x_irq_set_wake(struct irq_data *data, unsigned int on)
210{
211 struct pcf857x *gpio = irq_data_get_irq_chip_data(data);
212
213 int error = 0;
214
215 if (gpio->irq_parent) {
216 error = irq_set_irq_wake(gpio->irq_parent, on);
217 if (error) {
218 dev_dbg(&gpio->client->dev,
219 "irq %u doesn't support irq_set_wake\n",
220 gpio->irq_parent);
221 gpio->irq_parent = 0;
222 }
223 }
224 return error;
225}
226
227static void pcf857x_irq_enable(struct irq_data *data)
228{
229 struct pcf857x *gpio = irq_data_get_irq_chip_data(data);
230
231 gpio->irq_enabled |= (1 << data->hwirq);
232}
233
234static void pcf857x_irq_disable(struct irq_data *data)
235{
236 struct pcf857x *gpio = irq_data_get_irq_chip_data(data);
237
238 gpio->irq_enabled &= ~(1 << data->hwirq);
239}
240
241static void pcf857x_irq_bus_lock(struct irq_data *data)
242{
243 struct pcf857x *gpio = irq_data_get_irq_chip_data(data);
244
245 mutex_lock(&gpio->lock);
246}
247
248static void pcf857x_irq_bus_sync_unlock(struct irq_data *data)
249{
250 struct pcf857x *gpio = irq_data_get_irq_chip_data(data);
251
252 mutex_unlock(&gpio->lock);
253}
254
255static struct irq_chip pcf857x_irq_chip = {
256 .name = "pcf857x",
257 .irq_enable = pcf857x_irq_enable,
258 .irq_disable = pcf857x_irq_disable,
259 .irq_ack = noop,
260 .irq_mask = noop,
261 .irq_unmask = noop,
262 .irq_set_wake = pcf857x_irq_set_wake,
263 .irq_bus_lock = pcf857x_irq_bus_lock,
264 .irq_bus_sync_unlock = pcf857x_irq_bus_sync_unlock,
265};
266
267/*-------------------------------------------------------------------------*/
268
269static int pcf857x_probe(struct i2c_client *client,
270 const struct i2c_device_id *id)
271{
272 struct pcf857x_platform_data *pdata = dev_get_platdata(&client->dev);
273 struct device_node *np = client->dev.of_node;
274 struct pcf857x *gpio;
275 unsigned int n_latch = 0;
276 int status;
277
278 if (IS_ENABLED(CONFIG_OF) && np)
279 of_property_read_u32(np, "lines-initial-states", &n_latch);
280 else if (pdata)
281 n_latch = pdata->n_latch;
282 else
283 dev_dbg(&client->dev, "no platform data\n");
284
285 /* Allocate, initialize, and register this gpio_chip. */
286 gpio = devm_kzalloc(&client->dev, sizeof(*gpio), GFP_KERNEL);
287 if (!gpio)
288 return -ENOMEM;
289
290 mutex_init(&gpio->lock);
291
292 gpio->chip.base = pdata ? pdata->gpio_base : -1;
293 gpio->chip.can_sleep = true;
294 gpio->chip.parent = &client->dev;
295 gpio->chip.owner = THIS_MODULE;
296 gpio->chip.get = pcf857x_get;
297 gpio->chip.set = pcf857x_set;
298 gpio->chip.direction_input = pcf857x_input;
299 gpio->chip.direction_output = pcf857x_output;
300 gpio->chip.ngpio = id->driver_data;
301
302 /* NOTE: the OnSemi jlc1562b is also largely compatible with
303 * these parts, notably for output. It has a low-resolution
304 * DAC instead of pin change IRQs; and its inputs can be the
305 * result of comparators.
306 */
307
308 /* 8574 addresses are 0x20..0x27; 8574a uses 0x38..0x3f;
309 * 9670, 9672, 9764, and 9764a use quite a variety.
310 *
311 * NOTE: we don't distinguish here between *4 and *4a parts.
312 */
313 if (gpio->chip.ngpio == 8) {
314 gpio->write = i2c_write_le8;
315 gpio->read = i2c_read_le8;
316
317 if (!i2c_check_functionality(client->adapter,
318 I2C_FUNC_SMBUS_BYTE))
319 status = -EIO;
320
321 /* fail if there's no chip present */
322 else
323 status = i2c_smbus_read_byte(client);
324
325 /* '75/'75c addresses are 0x20..0x27, just like the '74;
326 * the '75c doesn't have a current source pulling high.
327 * 9671, 9673, and 9765 use quite a variety of addresses.
328 *
329 * NOTE: we don't distinguish here between '75 and '75c parts.
330 */
331 } else if (gpio->chip.ngpio == 16) {
332 gpio->write = i2c_write_le16;
333 gpio->read = i2c_read_le16;
334
335 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
336 status = -EIO;
337
338 /* fail if there's no chip present */
339 else
340 status = i2c_read_le16(client);
341
342 } else {
343 dev_dbg(&client->dev, "unsupported number of gpios\n");
344 status = -EINVAL;
345 }
346
347 if (status < 0)
348 goto fail;
349
350 gpio->chip.label = client->name;
351
352 gpio->client = client;
353 i2c_set_clientdata(client, gpio);
354
355 /* NOTE: these chips have strange "quasi-bidirectional" I/O pins.
356 * We can't actually know whether a pin is configured (a) as output
357 * and driving the signal low, or (b) as input and reporting a low
358 * value ... without knowing the last value written since the chip
359 * came out of reset (if any). We can't read the latched output.
360 *
361 * In short, the only reliable solution for setting up pin direction
362 * is to do it explicitly. The setup() method can do that, but it
363 * may cause transient glitching since it can't know the last value
364 * written (some pins may need to be driven low).
365 *
366 * Using n_latch avoids that trouble. When left initialized to zero,
367 * our software copy of the "latch" then matches the chip's all-ones
368 * reset state. Otherwise it flags pins to be driven low.
369 */
370 gpio->out = ~n_latch;
371 gpio->status = gpio->out;
372
373 status = devm_gpiochip_add_data(&client->dev, &gpio->chip, gpio);
374 if (status < 0)
375 goto fail;
376
377 /* Enable irqchip if we have an interrupt */
378 if (client->irq) {
379 status = gpiochip_irqchip_add_nested(&gpio->chip,
380 &pcf857x_irq_chip,
381 0, handle_level_irq,
382 IRQ_TYPE_NONE);
383 if (status) {
384 dev_err(&client->dev, "cannot add irqchip\n");
385 goto fail;
386 }
387
388 status = devm_request_threaded_irq(&client->dev, client->irq,
389 NULL, pcf857x_irq, IRQF_ONESHOT |
390 IRQF_TRIGGER_FALLING | IRQF_SHARED,
391 dev_name(&client->dev), gpio);
392 if (status)
393 goto fail;
394
395 gpiochip_set_nested_irqchip(&gpio->chip, &pcf857x_irq_chip,
396 client->irq);
397 gpio->irq_parent = client->irq;
398 }
399
400 /* Let platform code set up the GPIOs and their users.
401 * Now is the first time anyone could use them.
402 */
403 if (pdata && pdata->setup) {
404 status = pdata->setup(client,
405 gpio->chip.base, gpio->chip.ngpio,
406 pdata->context);
407 if (status < 0)
408 dev_warn(&client->dev, "setup --> %d\n", status);
409 }
410
411 dev_info(&client->dev, "probed\n");
412
413 return 0;
414
415fail:
416 dev_dbg(&client->dev, "probe error %d for '%s'\n", status,
417 client->name);
418
419 return status;
420}
421
422static int pcf857x_remove(struct i2c_client *client)
423{
424 struct pcf857x_platform_data *pdata = dev_get_platdata(&client->dev);
425 struct pcf857x *gpio = i2c_get_clientdata(client);
426 int status = 0;
427
428 if (pdata && pdata->teardown) {
429 status = pdata->teardown(client,
430 gpio->chip.base, gpio->chip.ngpio,
431 pdata->context);
432 if (status < 0) {
433 dev_err(&client->dev, "%s --> %d\n",
434 "teardown", status);
435 return status;
436 }
437 }
438
439 return status;
440}
441
442static void pcf857x_shutdown(struct i2c_client *client)
443{
444 struct pcf857x *gpio = i2c_get_clientdata(client);
445
446 /* Drive all the I/O lines high */
447 gpio->write(gpio->client, BIT(gpio->chip.ngpio) - 1);
448}
449
450static struct i2c_driver pcf857x_driver = {
451 .driver = {
452 .name = "pcf857x",
453 .of_match_table = of_match_ptr(pcf857x_of_table),
454 },
455 .probe = pcf857x_probe,
456 .remove = pcf857x_remove,
457 .shutdown = pcf857x_shutdown,
458 .id_table = pcf857x_id,
459};
460
461static int __init pcf857x_init(void)
462{
463 return i2c_add_driver(&pcf857x_driver);
464}
465/* register after i2c postcore initcall and before
466 * subsys initcalls that may rely on these GPIOs
467 */
468subsys_initcall(pcf857x_init);
469
470static void __exit pcf857x_exit(void)
471{
472 i2c_del_driver(&pcf857x_driver);
473}
474module_exit(pcf857x_exit);
475
476MODULE_LICENSE("GPL");
477MODULE_AUTHOR("David Brownell");