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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 | ||
22 | static 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 | }; | |
38 | MODULE_DEVICE_TABLE(i2c, pcf857x_id); | |
39 | ||
40 | #ifdef CONFIG_OF | |
41 | static 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 | }; | |
57 | MODULE_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 | */ | |
72 | struct 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 | ||
89 | static int i2c_write_le8(struct i2c_client *client, unsigned data) | |
90 | { | |
91 | return i2c_smbus_write_byte(client, data); | |
92 | } | |
93 | ||
94 | static 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 | ||
101 | static 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 | ||
110 | static 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 | ||
123 | static 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 | ||
136 | static 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 | ||
145 | static 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 | ||
162 | static void pcf857x_set(struct gpio_chip *chip, unsigned offset, int value) | |
163 | { | |
164 | pcf857x_output(chip, offset, value); | |
165 | } | |
166 | ||
167 | /*-------------------------------------------------------------------------*/ | |
168 | ||
169 | static 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 | */ | |
194 | static void noop(struct irq_data *data) { } | |
195 | ||
196 | static 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 | ||
203 | static 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 | ||
210 | static 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 | ||
217 | static 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 | ||
224 | static 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 | ||
233 | static 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->read(gpio->client); | |
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 | ||
388 | fail: | |
389 | dev_dbg(&client->dev, "probe error %d for '%s'\n", status, | |
390 | client->name); | |
391 | ||
392 | return status; | |
393 | } | |
394 | ||
395 | static 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 | ||
415 | static 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 | ||
423 | static 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 | ||
434 | static 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 | */ | |
441 | subsys_initcall(pcf857x_init); | |
442 | ||
443 | static void __exit pcf857x_exit(void) | |
444 | { | |
445 | i2c_del_driver(&pcf857x_driver); | |
446 | } | |
447 | module_exit(pcf857x_exit); | |
448 | ||
449 | MODULE_LICENSE("GPL"); | |
450 | MODULE_AUTHOR("David Brownell"); |