blob: 076e236d0da74b71734a3159bf287b4e11e04b0a [file] [log] [blame]
David Brownell15fae372008-02-04 22:28:24 -08001/*
Grant Likelyc103de22011-06-04 18:38:28 -06002 * Driver for pcf857x, pca857x, and pca967x I2C GPIO expanders
David Brownell15fae372008-02-04 22:28:24 -08003 *
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>
H Hartley Sweetend120c172009-09-22 16:46:37 -070023#include <linux/gpio.h>
David Brownell15fae372008-02-04 22:28:24 -080024#include <linux/i2c.h>
25#include <linux/i2c/pcf857x.h>
Paul Gortmakerbb207ef2011-07-03 13:38:09 -040026#include <linux/module.h>
David Brownell15fae372008-02-04 22:28:24 -080027
David Brownell15fae372008-02-04 22:28:24 -080028
Jean Delvare3760f732008-04-29 23:11:40 +020029static const struct i2c_device_id pcf857x_id[] = {
30 { "pcf8574", 8 },
Wolfram Sang4ba2ccb2009-09-18 22:45:47 +020031 { "pcf8574a", 8 },
Jean Delvare3760f732008-04-29 23:11:40 +020032 { "pca8574", 8 },
33 { "pca9670", 8 },
34 { "pca9672", 8 },
35 { "pca9674", 8 },
36 { "pcf8575", 16 },
37 { "pca8575", 16 },
38 { "pca9671", 16 },
39 { "pca9673", 16 },
40 { "pca9675", 16 },
David Brownell1673ad52008-07-21 14:21:34 -070041 { "max7328", 8 },
42 { "max7329", 8 },
Jean Delvare3760f732008-04-29 23:11:40 +020043 { }
44};
45MODULE_DEVICE_TABLE(i2c, pcf857x_id);
46
David Brownell15fae372008-02-04 22:28:24 -080047/*
48 * The pcf857x, pca857x, and pca967x chips only expose one read and one
49 * write register. Writing a "one" bit (to match the reset state) lets
50 * that pin be used as an input; it's not an open-drain model, but acts
51 * a bit like one. This is described as "quasi-bidirectional"; read the
52 * chip documentation for details.
53 *
54 * Many other I2C GPIO expander chips (like the pca953x models) have
55 * more complex register models and more conventional circuitry using
56 * push/pull drivers. They often use the same 0x20..0x27 addresses as
57 * pcf857x parts, making the "legacy" I2C driver model problematic.
58 */
59struct pcf857x {
60 struct gpio_chip chip;
61 struct i2c_client *client;
David Brownell1673ad52008-07-21 14:21:34 -070062 struct mutex lock; /* protect 'out' */
David Brownell15fae372008-02-04 22:28:24 -080063 unsigned out; /* software latch */
Kuninori Morimoto0c65ddd2012-06-13 21:58:08 -070064
65 int (*write)(struct i2c_client *client, unsigned data);
66 int (*read)(struct i2c_client *client);
David Brownell15fae372008-02-04 22:28:24 -080067};
68
69/*-------------------------------------------------------------------------*/
70
71/* Talk to 8-bit I/O expander */
72
Kuninori Morimoto0c65ddd2012-06-13 21:58:08 -070073static int i2c_write_le8(struct i2c_client *client, unsigned data)
David Brownell15fae372008-02-04 22:28:24 -080074{
Kuninori Morimoto0c65ddd2012-06-13 21:58:08 -070075 return i2c_smbus_write_byte(client, data);
David Brownell15fae372008-02-04 22:28:24 -080076}
77
Kuninori Morimoto0c65ddd2012-06-13 21:58:08 -070078static int i2c_read_le8(struct i2c_client *client)
David Brownell15fae372008-02-04 22:28:24 -080079{
Kuninori Morimoto0c65ddd2012-06-13 21:58:08 -070080 return (int)i2c_smbus_read_byte(client);
David Brownell15fae372008-02-04 22:28:24 -080081}
82
David Brownell15fae372008-02-04 22:28:24 -080083/* Talk to 16-bit I/O expander */
84
Kuninori Morimoto0c65ddd2012-06-13 21:58:08 -070085static int i2c_write_le16(struct i2c_client *client, unsigned word)
David Brownell15fae372008-02-04 22:28:24 -080086{
87 u8 buf[2] = { word & 0xff, word >> 8, };
88 int status;
89
90 status = i2c_master_send(client, buf, 2);
91 return (status < 0) ? status : 0;
92}
93
94static int i2c_read_le16(struct i2c_client *client)
95{
96 u8 buf[2];
97 int status;
98
99 status = i2c_master_recv(client, buf, 2);
100 if (status < 0)
101 return status;
102 return (buf[1] << 8) | buf[0];
103}
104
Kuninori Morimoto0c65ddd2012-06-13 21:58:08 -0700105/*-------------------------------------------------------------------------*/
106
107static int pcf857x_input(struct gpio_chip *chip, unsigned offset)
David Brownell15fae372008-02-04 22:28:24 -0800108{
109 struct pcf857x *gpio = container_of(chip, struct pcf857x, chip);
David Brownell1673ad52008-07-21 14:21:34 -0700110 int status;
David Brownell15fae372008-02-04 22:28:24 -0800111
David Brownell1673ad52008-07-21 14:21:34 -0700112 mutex_lock(&gpio->lock);
David Brownell15fae372008-02-04 22:28:24 -0800113 gpio->out |= (1 << offset);
Kuninori Morimoto0c65ddd2012-06-13 21:58:08 -0700114 status = gpio->write(gpio->client, gpio->out);
David Brownell1673ad52008-07-21 14:21:34 -0700115 mutex_unlock(&gpio->lock);
116
117 return status;
David Brownell15fae372008-02-04 22:28:24 -0800118}
119
Kuninori Morimoto0c65ddd2012-06-13 21:58:08 -0700120static int pcf857x_get(struct gpio_chip *chip, unsigned offset)
David Brownell15fae372008-02-04 22:28:24 -0800121{
122 struct pcf857x *gpio = container_of(chip, struct pcf857x, chip);
123 int value;
124
Kuninori Morimoto0c65ddd2012-06-13 21:58:08 -0700125 value = gpio->read(gpio->client);
David Brownell15fae372008-02-04 22:28:24 -0800126 return (value < 0) ? 0 : (value & (1 << offset));
127}
128
Kuninori Morimoto0c65ddd2012-06-13 21:58:08 -0700129static int pcf857x_output(struct gpio_chip *chip, unsigned offset, int value)
David Brownell15fae372008-02-04 22:28:24 -0800130{
131 struct pcf857x *gpio = container_of(chip, struct pcf857x, chip);
132 unsigned bit = 1 << offset;
David Brownell1673ad52008-07-21 14:21:34 -0700133 int status;
David Brownell15fae372008-02-04 22:28:24 -0800134
David Brownell1673ad52008-07-21 14:21:34 -0700135 mutex_lock(&gpio->lock);
David Brownell15fae372008-02-04 22:28:24 -0800136 if (value)
137 gpio->out |= bit;
138 else
139 gpio->out &= ~bit;
Kuninori Morimoto0c65ddd2012-06-13 21:58:08 -0700140 status = gpio->write(gpio->client, gpio->out);
David Brownell1673ad52008-07-21 14:21:34 -0700141 mutex_unlock(&gpio->lock);
142
143 return status;
David Brownell15fae372008-02-04 22:28:24 -0800144}
145
Kuninori Morimoto0c65ddd2012-06-13 21:58:08 -0700146static void pcf857x_set(struct gpio_chip *chip, unsigned offset, int value)
David Brownell15fae372008-02-04 22:28:24 -0800147{
Kuninori Morimoto0c65ddd2012-06-13 21:58:08 -0700148 pcf857x_output(chip, offset, value);
David Brownell15fae372008-02-04 22:28:24 -0800149}
150
151/*-------------------------------------------------------------------------*/
152
Jean Delvared2653e92008-04-29 23:11:39 +0200153static int pcf857x_probe(struct i2c_client *client,
154 const struct i2c_device_id *id)
David Brownell15fae372008-02-04 22:28:24 -0800155{
156 struct pcf857x_platform_data *pdata;
157 struct pcf857x *gpio;
158 int status;
159
160 pdata = client->dev.platform_data;
Ben Dooksa342d212009-01-15 13:50:45 -0800161 if (!pdata) {
162 dev_dbg(&client->dev, "no platform data\n");
Ben Dooksa342d212009-01-15 13:50:45 -0800163 }
David Brownell15fae372008-02-04 22:28:24 -0800164
165 /* Allocate, initialize, and register this gpio_chip. */
166 gpio = kzalloc(sizeof *gpio, GFP_KERNEL);
167 if (!gpio)
168 return -ENOMEM;
169
David Brownell1673ad52008-07-21 14:21:34 -0700170 mutex_init(&gpio->lock);
171
Kuninori Morimoto0c65ddd2012-06-13 21:58:08 -0700172 gpio->chip.base = pdata ? pdata->gpio_base : -1;
173 gpio->chip.can_sleep = 1;
174 gpio->chip.dev = &client->dev;
175 gpio->chip.owner = THIS_MODULE;
176 gpio->chip.get = pcf857x_get;
177 gpio->chip.set = pcf857x_set;
178 gpio->chip.direction_input = pcf857x_input;
179 gpio->chip.direction_output = pcf857x_output;
180 gpio->chip.ngpio = id->driver_data;
David Brownell15fae372008-02-04 22:28:24 -0800181
182 /* NOTE: the OnSemi jlc1562b is also largely compatible with
183 * these parts, notably for output. It has a low-resolution
184 * DAC instead of pin change IRQs; and its inputs can be the
185 * result of comparators.
186 */
187
188 /* 8574 addresses are 0x20..0x27; 8574a uses 0x38..0x3f;
189 * 9670, 9672, 9764, and 9764a use quite a variety.
190 *
191 * NOTE: we don't distinguish here between *4 and *4a parts.
192 */
Jean Delvare3760f732008-04-29 23:11:40 +0200193 if (gpio->chip.ngpio == 8) {
Kuninori Morimoto0c65ddd2012-06-13 21:58:08 -0700194 gpio->write = i2c_write_le8;
195 gpio->read = i2c_read_le8;
David Brownell15fae372008-02-04 22:28:24 -0800196
197 if (!i2c_check_functionality(client->adapter,
198 I2C_FUNC_SMBUS_BYTE))
199 status = -EIO;
200
201 /* fail if there's no chip present */
202 else
203 status = i2c_smbus_read_byte(client);
204
205 /* '75/'75c addresses are 0x20..0x27, just like the '74;
206 * the '75c doesn't have a current source pulling high.
207 * 9671, 9673, and 9765 use quite a variety of addresses.
208 *
209 * NOTE: we don't distinguish here between '75 and '75c parts.
210 */
Jean Delvare3760f732008-04-29 23:11:40 +0200211 } else if (gpio->chip.ngpio == 16) {
Kuninori Morimoto0c65ddd2012-06-13 21:58:08 -0700212 gpio->write = i2c_write_le16;
213 gpio->read = i2c_read_le16;
David Brownell15fae372008-02-04 22:28:24 -0800214
215 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
216 status = -EIO;
217
218 /* fail if there's no chip present */
219 else
220 status = i2c_read_le16(client);
221
Ben Dooksa342d212009-01-15 13:50:45 -0800222 } else {
223 dev_dbg(&client->dev, "unsupported number of gpios\n");
224 status = -EINVAL;
225 }
David Brownell15fae372008-02-04 22:28:24 -0800226
227 if (status < 0)
228 goto fail;
229
230 gpio->chip.label = client->name;
231
232 gpio->client = client;
233 i2c_set_clientdata(client, gpio);
234
235 /* NOTE: these chips have strange "quasi-bidirectional" I/O pins.
236 * We can't actually know whether a pin is configured (a) as output
237 * and driving the signal low, or (b) as input and reporting a low
238 * value ... without knowing the last value written since the chip
239 * came out of reset (if any). We can't read the latched output.
240 *
241 * In short, the only reliable solution for setting up pin direction
242 * is to do it explicitly. The setup() method can do that, but it
243 * may cause transient glitching since it can't know the last value
244 * written (some pins may need to be driven low).
245 *
246 * Using pdata->n_latch avoids that trouble. When left initialized
247 * to zero, our software copy of the "latch" then matches the chip's
248 * all-ones reset state. Otherwise it flags pins to be driven low.
249 */
Dmitry Eremin-Solenikov49946f62010-08-10 18:02:24 -0700250 gpio->out = pdata ? ~pdata->n_latch : ~0;
David Brownell15fae372008-02-04 22:28:24 -0800251
252 status = gpiochip_add(&gpio->chip);
253 if (status < 0)
254 goto fail;
255
256 /* NOTE: these chips can issue "some pin-changed" IRQs, which we
257 * don't yet even try to use. Among other issues, the relevant
258 * genirq state isn't available to modular drivers; and most irq
259 * methods can't be called from sleeping contexts.
260 */
261
Grant Likely64842aa2011-11-06 11:36:18 -0700262 dev_info(&client->dev, "%s\n",
David Brownell15fae372008-02-04 22:28:24 -0800263 client->irq ? " (irq ignored)" : "");
264
265 /* Let platform code set up the GPIOs and their users.
266 * Now is the first time anyone could use them.
267 */
Dmitry Eremin-Solenikov49946f62010-08-10 18:02:24 -0700268 if (pdata && pdata->setup) {
David Brownell15fae372008-02-04 22:28:24 -0800269 status = pdata->setup(client,
270 gpio->chip.base, gpio->chip.ngpio,
271 pdata->context);
272 if (status < 0)
273 dev_warn(&client->dev, "setup --> %d\n", status);
274 }
275
276 return 0;
277
278fail:
279 dev_dbg(&client->dev, "probe error %d for '%s'\n",
280 status, client->name);
281 kfree(gpio);
282 return status;
283}
284
285static int pcf857x_remove(struct i2c_client *client)
286{
287 struct pcf857x_platform_data *pdata = client->dev.platform_data;
288 struct pcf857x *gpio = i2c_get_clientdata(client);
289 int status = 0;
290
Dmitry Eremin-Solenikov49946f62010-08-10 18:02:24 -0700291 if (pdata && pdata->teardown) {
David Brownell15fae372008-02-04 22:28:24 -0800292 status = pdata->teardown(client,
293 gpio->chip.base, gpio->chip.ngpio,
294 pdata->context);
295 if (status < 0) {
296 dev_err(&client->dev, "%s --> %d\n",
297 "teardown", status);
298 return status;
299 }
300 }
301
302 status = gpiochip_remove(&gpio->chip);
303 if (status == 0)
304 kfree(gpio);
305 else
306 dev_err(&client->dev, "%s --> %d\n", "remove", status);
307 return status;
308}
309
310static struct i2c_driver pcf857x_driver = {
311 .driver = {
312 .name = "pcf857x",
313 .owner = THIS_MODULE,
314 },
315 .probe = pcf857x_probe,
316 .remove = pcf857x_remove,
Jean Delvare3760f732008-04-29 23:11:40 +0200317 .id_table = pcf857x_id,
David Brownell15fae372008-02-04 22:28:24 -0800318};
319
320static int __init pcf857x_init(void)
321{
322 return i2c_add_driver(&pcf857x_driver);
323}
David Brownell2f8d1192008-10-15 22:03:13 -0700324/* register after i2c postcore initcall and before
325 * subsys initcalls that may rely on these GPIOs
326 */
327subsys_initcall(pcf857x_init);
David Brownell15fae372008-02-04 22:28:24 -0800328
329static void __exit pcf857x_exit(void)
330{
331 i2c_del_driver(&pcf857x_driver);
332}
333module_exit(pcf857x_exit);
334
335MODULE_LICENSE("GPL");
336MODULE_AUTHOR("David Brownell");