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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/kernel.h>
22#include <linux/slab.h>
23#include <linux/gpio.h>
24#include <linux/i2c.h>
25#include <linux/i2c/pcf857x.h>
26
27
28static const struct i2c_device_id pcf857x_id[] = {
29 { "pcf8574", 8 },
30 { "pcf8574a", 8 },
31 { "pca8574", 8 },
32 { "pca9670", 8 },
33 { "pca9672", 8 },
34 { "pca9674", 8 },
35 { "pcf8575", 16 },
36 { "pca8575", 16 },
37 { "pca9671", 16 },
38 { "pca9673", 16 },
39 { "pca9675", 16 },
40 { "max7328", 8 },
41 { "max7329", 8 },
42 { }
43};
44MODULE_DEVICE_TABLE(i2c, pcf857x_id);
45
46/*
47 * The pcf857x, pca857x, and pca967x chips only expose one read and one
48 * write register. Writing a "one" bit (to match the reset state) lets
49 * that pin be used as an input; it's not an open-drain model, but acts
50 * a bit like one. This is described as "quasi-bidirectional"; read the
51 * chip documentation for details.
52 *
53 * Many other I2C GPIO expander chips (like the pca953x models) have
54 * more complex register models and more conventional circuitry using
55 * push/pull drivers. They often use the same 0x20..0x27 addresses as
56 * pcf857x parts, making the "legacy" I2C driver model problematic.
57 */
58struct pcf857x {
59 struct gpio_chip chip;
60 struct i2c_client *client;
61 struct mutex lock; /* protect 'out' */
62 unsigned out; /* software latch */
63};
64
65/*-------------------------------------------------------------------------*/
66
67/* Talk to 8-bit I/O expander */
68
69static int pcf857x_input8(struct gpio_chip *chip, unsigned offset)
70{
71 struct pcf857x *gpio = container_of(chip, struct pcf857x, chip);
72 int status;
73
74 mutex_lock(&gpio->lock);
75 gpio->out |= (1 << offset);
76 status = i2c_smbus_write_byte(gpio->client, gpio->out);
77 mutex_unlock(&gpio->lock);
78
79 return status;
80}
81
82static int pcf857x_get8(struct gpio_chip *chip, unsigned offset)
83{
84 struct pcf857x *gpio = container_of(chip, struct pcf857x, chip);
85 s32 value;
86
87 value = i2c_smbus_read_byte(gpio->client);
88 return (value < 0) ? 0 : (value & (1 << offset));
89}
90
91static int pcf857x_output8(struct gpio_chip *chip, unsigned offset, int value)
92{
93 struct pcf857x *gpio = container_of(chip, struct pcf857x, chip);
94 unsigned bit = 1 << offset;
95 int status;
96
97 mutex_lock(&gpio->lock);
98 if (value)
99 gpio->out |= bit;
100 else
101 gpio->out &= ~bit;
102 status = i2c_smbus_write_byte(gpio->client, gpio->out);
103 mutex_unlock(&gpio->lock);
104
105 return status;
106}
107
108static void pcf857x_set8(struct gpio_chip *chip, unsigned offset, int value)
109{
110 pcf857x_output8(chip, offset, value);
111}
112
113/*-------------------------------------------------------------------------*/
114
115/* Talk to 16-bit I/O expander */
116
117static int i2c_write_le16(struct i2c_client *client, u16 word)
118{
119 u8 buf[2] = { word & 0xff, word >> 8, };
120 int status;
121
122 status = i2c_master_send(client, buf, 2);
123 return (status < 0) ? status : 0;
124}
125
126static int i2c_read_le16(struct i2c_client *client)
127{
128 u8 buf[2];
129 int status;
130
131 status = i2c_master_recv(client, buf, 2);
132 if (status < 0)
133 return status;
134 return (buf[1] << 8) | buf[0];
135}
136
137static int pcf857x_input16(struct gpio_chip *chip, unsigned offset)
138{
139 struct pcf857x *gpio = container_of(chip, struct pcf857x, chip);
140 int status;
141
142 mutex_lock(&gpio->lock);
143 gpio->out |= (1 << offset);
144 status = i2c_write_le16(gpio->client, gpio->out);
145 mutex_unlock(&gpio->lock);
146
147 return status;
148}
149
150static int pcf857x_get16(struct gpio_chip *chip, unsigned offset)
151{
152 struct pcf857x *gpio = container_of(chip, struct pcf857x, chip);
153 int value;
154
155 value = i2c_read_le16(gpio->client);
156 return (value < 0) ? 0 : (value & (1 << offset));
157}
158
159static int pcf857x_output16(struct gpio_chip *chip, unsigned offset, int value)
160{
161 struct pcf857x *gpio = container_of(chip, struct pcf857x, chip);
162 unsigned bit = 1 << offset;
163 int status;
164
165 mutex_lock(&gpio->lock);
166 if (value)
167 gpio->out |= bit;
168 else
169 gpio->out &= ~bit;
170 status = i2c_write_le16(gpio->client, gpio->out);
171 mutex_unlock(&gpio->lock);
172
173 return status;
174}
175
176static void pcf857x_set16(struct gpio_chip *chip, unsigned offset, int value)
177{
178 pcf857x_output16(chip, offset, value);
179}
180
181/*-------------------------------------------------------------------------*/
182
183static int pcf857x_probe(struct i2c_client *client,
184 const struct i2c_device_id *id)
185{
186 struct pcf857x_platform_data *pdata;
187 struct pcf857x *gpio;
188 int status;
189
190 pdata = client->dev.platform_data;
191 if (!pdata) {
192 dev_dbg(&client->dev, "no platform data\n");
193 }
194
195 /* Allocate, initialize, and register this gpio_chip. */
196 gpio = kzalloc(sizeof *gpio, GFP_KERNEL);
197 if (!gpio)
198 return -ENOMEM;
199
200 mutex_init(&gpio->lock);
201
202 gpio->chip.base = pdata ? pdata->gpio_base : -1;
203 gpio->chip.can_sleep = 1;
204 gpio->chip.dev = &client->dev;
205 gpio->chip.owner = THIS_MODULE;
206
207 /* NOTE: the OnSemi jlc1562b is also largely compatible with
208 * these parts, notably for output. It has a low-resolution
209 * DAC instead of pin change IRQs; and its inputs can be the
210 * result of comparators.
211 */
212
213 /* 8574 addresses are 0x20..0x27; 8574a uses 0x38..0x3f;
214 * 9670, 9672, 9764, and 9764a use quite a variety.
215 *
216 * NOTE: we don't distinguish here between *4 and *4a parts.
217 */
218 gpio->chip.ngpio = id->driver_data;
219 if (gpio->chip.ngpio == 8) {
220 gpio->chip.direction_input = pcf857x_input8;
221 gpio->chip.get = pcf857x_get8;
222 gpio->chip.direction_output = pcf857x_output8;
223 gpio->chip.set = pcf857x_set8;
224
225 if (!i2c_check_functionality(client->adapter,
226 I2C_FUNC_SMBUS_BYTE))
227 status = -EIO;
228
229 /* fail if there's no chip present */
230 else
231 status = i2c_smbus_read_byte(client);
232
233 /* '75/'75c addresses are 0x20..0x27, just like the '74;
234 * the '75c doesn't have a current source pulling high.
235 * 9671, 9673, and 9765 use quite a variety of addresses.
236 *
237 * NOTE: we don't distinguish here between '75 and '75c parts.
238 */
239 } else if (gpio->chip.ngpio == 16) {
240 gpio->chip.direction_input = pcf857x_input16;
241 gpio->chip.get = pcf857x_get16;
242 gpio->chip.direction_output = pcf857x_output16;
243 gpio->chip.set = pcf857x_set16;
244
245 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
246 status = -EIO;
247
248 /* fail if there's no chip present */
249 else
250 status = i2c_read_le16(client);
251
252 } else {
253 dev_dbg(&client->dev, "unsupported number of gpios\n");
254 status = -EINVAL;
255 }
256
257 if (status < 0)
258 goto fail;
259
260 gpio->chip.label = client->name;
261
262 gpio->client = client;
263 i2c_set_clientdata(client, gpio);
264
265 /* NOTE: these chips have strange "quasi-bidirectional" I/O pins.
266 * We can't actually know whether a pin is configured (a) as output
267 * and driving the signal low, or (b) as input and reporting a low
268 * value ... without knowing the last value written since the chip
269 * came out of reset (if any). We can't read the latched output.
270 *
271 * In short, the only reliable solution for setting up pin direction
272 * is to do it explicitly. The setup() method can do that, but it
273 * may cause transient glitching since it can't know the last value
274 * written (some pins may need to be driven low).
275 *
276 * Using pdata->n_latch avoids that trouble. When left initialized
277 * to zero, our software copy of the "latch" then matches the chip's
278 * all-ones reset state. Otherwise it flags pins to be driven low.
279 */
280 gpio->out = pdata ? ~pdata->n_latch : ~0;
281
282 status = gpiochip_add(&gpio->chip);
283 if (status < 0)
284 goto fail;
285
286 /* NOTE: these chips can issue "some pin-changed" IRQs, which we
287 * don't yet even try to use. Among other issues, the relevant
288 * genirq state isn't available to modular drivers; and most irq
289 * methods can't be called from sleeping contexts.
290 */
291
292 dev_info(&client->dev, "gpios %d..%d on a %s%s\n",
293 gpio->chip.base,
294 gpio->chip.base + gpio->chip.ngpio - 1,
295 client->name,
296 client->irq ? " (irq ignored)" : "");
297
298 /* Let platform code set up the GPIOs and their users.
299 * Now is the first time anyone could use them.
300 */
301 if (pdata && pdata->setup) {
302 status = pdata->setup(client,
303 gpio->chip.base, gpio->chip.ngpio,
304 pdata->context);
305 if (status < 0)
306 dev_warn(&client->dev, "setup --> %d\n", status);
307 }
308
309 return 0;
310
311fail:
312 dev_dbg(&client->dev, "probe error %d for '%s'\n",
313 status, client->name);
314 kfree(gpio);
315 return status;
316}
317
318static int pcf857x_remove(struct i2c_client *client)
319{
320 struct pcf857x_platform_data *pdata = client->dev.platform_data;
321 struct pcf857x *gpio = i2c_get_clientdata(client);
322 int status = 0;
323
324 if (pdata && pdata->teardown) {
325 status = pdata->teardown(client,
326 gpio->chip.base, gpio->chip.ngpio,
327 pdata->context);
328 if (status < 0) {
329 dev_err(&client->dev, "%s --> %d\n",
330 "teardown", status);
331 return status;
332 }
333 }
334
335 status = gpiochip_remove(&gpio->chip);
336 if (status == 0)
337 kfree(gpio);
338 else
339 dev_err(&client->dev, "%s --> %d\n", "remove", status);
340 return status;
341}
342
343static struct i2c_driver pcf857x_driver = {
344 .driver = {
345 .name = "pcf857x",
346 .owner = THIS_MODULE,
347 },
348 .probe = pcf857x_probe,
349 .remove = pcf857x_remove,
350 .id_table = pcf857x_id,
351};
352
353static int __init pcf857x_init(void)
354{
355 return i2c_add_driver(&pcf857x_driver);
356}
357/* register after i2c postcore initcall and before
358 * subsys initcalls that may rely on these GPIOs
359 */
360subsys_initcall(pcf857x_init);
361
362static void __exit pcf857x_exit(void)
363{
364 i2c_del_driver(&pcf857x_driver);
365}
366module_exit(pcf857x_exit);
367
368MODULE_LICENSE("GPL");
369MODULE_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/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>
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 { "tca9554", 8 },
50 { }
51};
52MODULE_DEVICE_TABLE(i2c, pcf857x_id);
53
54#ifdef CONFIG_OF
55static 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 { }
71};
72MODULE_DEVICE_TABLE(of, pcf857x_of_table);
73#endif
74
75/*
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.
81 *
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.
86 */
87struct 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 */
95
96 int (*write)(struct i2c_client *client, unsigned data);
97 int (*read)(struct i2c_client *client);
98};
99
100/*-------------------------------------------------------------------------*/
101
102/* Talk to 8-bit I/O expander */
103
104static int i2c_write_le8(struct i2c_client *client, unsigned data)
105{
106 return i2c_smbus_write_byte(client, data);
107}
108
109static int i2c_read_le8(struct i2c_client *client)
110{
111 return (int)i2c_smbus_read_byte(client);
112}
113
114/* Talk to 16-bit I/O expander */
115
116static int i2c_write_le16(struct i2c_client *client, unsigned word)
117{
118 u8 buf[2] = { word & 0xff, word >> 8, };
119 int status;
120
121 status = i2c_master_send(client, buf, 2);
122 return (status < 0) ? status : 0;
123}
124
125static int i2c_read_le16(struct i2c_client *client)
126{
127 u8 buf[2];
128 int status;
129
130 status = i2c_master_recv(client, buf, 2);
131 if (status < 0)
132 return status;
133 return (buf[1] << 8) | buf[0];
134}
135
136/*-------------------------------------------------------------------------*/
137
138static int pcf857x_input(struct gpio_chip *chip, unsigned offset)
139{
140 struct pcf857x *gpio = gpiochip_get_data(chip);
141 int status;
142
143 mutex_lock(&gpio->lock);
144 gpio->out |= (1 << offset);
145 status = gpio->write(gpio->client, gpio->out);
146 mutex_unlock(&gpio->lock);
147
148 return status;
149}
150
151static int pcf857x_get(struct gpio_chip *chip, unsigned offset)
152{
153 struct pcf857x *gpio = gpiochip_get_data(chip);
154 int value;
155
156 value = gpio->read(gpio->client);
157 return (value < 0) ? value : !!(value & (1 << offset));
158}
159
160static int pcf857x_output(struct gpio_chip *chip, unsigned offset, int value)
161{
162 struct pcf857x *gpio = gpiochip_get_data(chip);
163 unsigned bit = 1 << offset;
164 int status;
165
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);
173
174 return status;
175}
176
177static void pcf857x_set(struct gpio_chip *chip, unsigned offset, int value)
178{
179 pcf857x_output(chip, offset, value);
180}
181
182/*-------------------------------------------------------------------------*/
183
184static irqreturn_t pcf857x_irq(int irq, void *data)
185{
186 struct pcf857x *gpio = data;
187 unsigned long change, i, status;
188
189 status = gpio->read(gpio->client);
190
191 /*
192 * call the interrupt handler iff gpio is used as
193 * interrupt source, just to avoid bad irqs
194 */
195 mutex_lock(&gpio->lock);
196 change = (gpio->status ^ status) & gpio->irq_enabled;
197 gpio->status = status;
198 mutex_unlock(&gpio->lock);
199
200 for_each_set_bit(i, &change, gpio->chip.ngpio)
201 handle_nested_irq(irq_find_mapping(gpio->chip.irqdomain, i));
202
203 return IRQ_HANDLED;
204}
205
206/*
207 * NOP functions
208 */
209static void noop(struct irq_data *data) { }
210
211static int pcf857x_irq_set_wake(struct irq_data *data, unsigned int on)
212{
213 struct pcf857x *gpio = irq_data_get_irq_chip_data(data);
214
215 int error = 0;
216
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;
224 }
225 }
226 return error;
227}
228
229static void pcf857x_irq_enable(struct irq_data *data)
230{
231 struct pcf857x *gpio = irq_data_get_irq_chip_data(data);
232
233 gpio->irq_enabled |= (1 << data->hwirq);
234}
235
236static void pcf857x_irq_disable(struct irq_data *data)
237{
238 struct pcf857x *gpio = irq_data_get_irq_chip_data(data);
239
240 gpio->irq_enabled &= ~(1 << data->hwirq);
241}
242
243static void pcf857x_irq_bus_lock(struct irq_data *data)
244{
245 struct pcf857x *gpio = irq_data_get_irq_chip_data(data);
246
247 mutex_lock(&gpio->lock);
248}
249
250static void pcf857x_irq_bus_sync_unlock(struct irq_data *data)
251{
252 struct pcf857x *gpio = irq_data_get_irq_chip_data(data);
253
254 mutex_unlock(&gpio->lock);
255}
256
257static 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,
267};
268
269/*-------------------------------------------------------------------------*/
270
271static int pcf857x_probe(struct i2c_client *client,
272 const struct i2c_device_id *id)
273{
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;
279
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");
286
287 /* Allocate, initialize, and register this gpio_chip. */
288 gpio = devm_kzalloc(&client->dev, sizeof(*gpio), GFP_KERNEL);
289 if (!gpio)
290 return -ENOMEM;
291
292 mutex_init(&gpio->lock);
293
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;
303
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.
308 */
309
310 /* 8574 addresses are 0x20..0x27; 8574a uses 0x38..0x3f;
311 * 9670, 9672, 9764, and 9764a use quite a variety.
312 *
313 * NOTE: we don't distinguish here between *4 and *4a parts.
314 */
315 if (gpio->chip.ngpio == 8) {
316 gpio->write = i2c_write_le8;
317 gpio->read = i2c_read_le8;
318
319 if (!i2c_check_functionality(client->adapter,
320 I2C_FUNC_SMBUS_BYTE))
321 status = -EIO;
322
323 /* fail if there's no chip present */
324 else
325 status = i2c_smbus_read_byte(client);
326
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.
330 *
331 * NOTE: we don't distinguish here between '75 and '75c parts.
332 */
333 } else if (gpio->chip.ngpio == 16) {
334 gpio->write = i2c_write_le16;
335 gpio->read = i2c_read_le16;
336
337 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
338 status = -EIO;
339
340 /* fail if there's no chip present */
341 else
342 status = i2c_read_le16(client);
343
344 } else {
345 dev_dbg(&client->dev, "unsupported number of gpios\n");
346 status = -EINVAL;
347 }
348
349 if (status < 0)
350 goto fail;
351
352 gpio->chip.label = client->name;
353
354 gpio->client = client;
355 i2c_set_clientdata(client, gpio);
356
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.
362 *
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).
367 *
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.
371 */
372 gpio->out = ~n_latch;
373 gpio->status = gpio->out;
374
375 status = devm_gpiochip_add_data(&client->dev, &gpio->chip, gpio);
376 if (status < 0)
377 goto fail;
378
379 /* Enable irqchip if we have an interrupt */
380 if (client->irq) {
381 status = gpiochip_irqchip_add_nested(&gpio->chip,
382 &pcf857x_irq_chip,
383 0, handle_level_irq,
384 IRQ_TYPE_NONE);
385 if (status) {
386 dev_err(&client->dev, "cannot add irqchip\n");
387 goto fail;
388 }
389
390 status = devm_request_threaded_irq(&client->dev, client->irq,
391 NULL, pcf857x_irq, IRQF_ONESHOT |
392 IRQF_TRIGGER_FALLING | IRQF_SHARED,
393 dev_name(&client->dev), gpio);
394 if (status)
395 goto fail;
396
397 gpiochip_set_nested_irqchip(&gpio->chip, &pcf857x_irq_chip,
398 client->irq);
399 gpio->irq_parent = client->irq;
400 }
401
402 /* Let platform code set up the GPIOs and their users.
403 * Now is the first time anyone could use them.
404 */
405 if (pdata && pdata->setup) {
406 status = pdata->setup(client,
407 gpio->chip.base, gpio->chip.ngpio,
408 pdata->context);
409 if (status < 0)
410 dev_warn(&client->dev, "setup --> %d\n", status);
411 }
412
413 dev_info(&client->dev, "probed\n");
414
415 return 0;
416
417fail:
418 dev_dbg(&client->dev, "probe error %d for '%s'\n", status,
419 client->name);
420
421 return status;
422}
423
424static int pcf857x_remove(struct i2c_client *client)
425{
426 struct pcf857x_platform_data *pdata = dev_get_platdata(&client->dev);
427 struct pcf857x *gpio = i2c_get_clientdata(client);
428 int status = 0;
429
430 if (pdata && pdata->teardown) {
431 status = pdata->teardown(client,
432 gpio->chip.base, gpio->chip.ngpio,
433 pdata->context);
434 if (status < 0) {
435 dev_err(&client->dev, "%s --> %d\n",
436 "teardown", status);
437 return status;
438 }
439 }
440
441 return status;
442}
443
444static void pcf857x_shutdown(struct i2c_client *client)
445{
446 struct pcf857x *gpio = i2c_get_clientdata(client);
447
448 /* Drive all the I/O lines high */
449 gpio->write(gpio->client, BIT(gpio->chip.ngpio) - 1);
450}
451
452static struct i2c_driver pcf857x_driver = {
453 .driver = {
454 .name = "pcf857x",
455 .of_match_table = of_match_ptr(pcf857x_of_table),
456 },
457 .probe = pcf857x_probe,
458 .remove = pcf857x_remove,
459 .shutdown = pcf857x_shutdown,
460 .id_table = pcf857x_id,
461};
462
463static int __init pcf857x_init(void)
464{
465 return i2c_add_driver(&pcf857x_driver);
466}
467/* register after i2c postcore initcall and before
468 * subsys initcalls that may rely on these GPIOs
469 */
470subsys_initcall(pcf857x_init);
471
472static void __exit pcf857x_exit(void)
473{
474 i2c_del_driver(&pcf857x_driver);
475}
476module_exit(pcf857x_exit);
477
478MODULE_LICENSE("GPL");
479MODULE_AUTHOR("David Brownell");