blob: bb60e8c1a1f0621e3d06c8292d1007ab3e66c754 [file] [log] [blame]
David Brownelle58b9e22008-02-04 22:28:25 -08001/*
2 * mcp23s08.c - SPI gpio expander driver
3 */
4
5#include <linux/kernel.h>
6#include <linux/device.h>
7#include <linux/workqueue.h>
8#include <linux/mutex.h>
9
10#include <linux/spi/spi.h>
11#include <linux/spi/mcp23s08.h>
12
13#include <asm/gpio.h>
14
15
16/* Registers are all 8 bits wide.
17 *
18 * The mcp23s17 has twice as many bits, and can be configured to work
19 * with either 16 bit registers or with two adjacent 8 bit banks.
20 *
21 * Also, there are I2C versions of both chips.
22 */
23#define MCP_IODIR 0x00 /* init/reset: all ones */
24#define MCP_IPOL 0x01
25#define MCP_GPINTEN 0x02
26#define MCP_DEFVAL 0x03
27#define MCP_INTCON 0x04
28#define MCP_IOCON 0x05
29# define IOCON_SEQOP (1 << 5)
30# define IOCON_HAEN (1 << 3)
31# define IOCON_ODR (1 << 2)
32# define IOCON_INTPOL (1 << 1)
33#define MCP_GPPU 0x06
34#define MCP_INTF 0x07
35#define MCP_INTCAP 0x08
36#define MCP_GPIO 0x09
37#define MCP_OLAT 0x0a
38
39struct mcp23s08 {
40 struct spi_device *spi;
41 u8 addr;
42
43 /* lock protects the cached values */
44 struct mutex lock;
45 u8 cache[11];
46
47 struct gpio_chip chip;
48
49 struct work_struct work;
50};
51
52static int mcp23s08_read(struct mcp23s08 *mcp, unsigned reg)
53{
54 u8 tx[2], rx[1];
55 int status;
56
57 tx[0] = mcp->addr | 0x01;
58 tx[1] = reg;
59 status = spi_write_then_read(mcp->spi, tx, sizeof tx, rx, sizeof rx);
60 return (status < 0) ? status : rx[0];
61}
62
63static int mcp23s08_write(struct mcp23s08 *mcp, unsigned reg, u8 val)
64{
65 u8 tx[3];
66
67 tx[0] = mcp->addr;
68 tx[1] = reg;
69 tx[2] = val;
70 return spi_write_then_read(mcp->spi, tx, sizeof tx, NULL, 0);
71}
72
73static int
74mcp23s08_read_regs(struct mcp23s08 *mcp, unsigned reg, u8 *vals, unsigned n)
75{
76 u8 tx[2];
77
78 if ((n + reg) > sizeof mcp->cache)
79 return -EINVAL;
80 tx[0] = mcp->addr | 0x01;
81 tx[1] = reg;
82 return spi_write_then_read(mcp->spi, tx, sizeof tx, vals, n);
83}
84
85/*----------------------------------------------------------------------*/
86
87static int mcp23s08_direction_input(struct gpio_chip *chip, unsigned offset)
88{
89 struct mcp23s08 *mcp = container_of(chip, struct mcp23s08, chip);
90 int status;
91
92 mutex_lock(&mcp->lock);
93 mcp->cache[MCP_IODIR] |= (1 << offset);
94 status = mcp23s08_write(mcp, MCP_IODIR, mcp->cache[MCP_IODIR]);
95 mutex_unlock(&mcp->lock);
96 return status;
97}
98
99static int mcp23s08_get(struct gpio_chip *chip, unsigned offset)
100{
101 struct mcp23s08 *mcp = container_of(chip, struct mcp23s08, chip);
102 int status;
103
104 mutex_lock(&mcp->lock);
105
106 /* REVISIT reading this clears any IRQ ... */
107 status = mcp23s08_read(mcp, MCP_GPIO);
108 if (status < 0)
109 status = 0;
110 else {
111 mcp->cache[MCP_GPIO] = status;
112 status = !!(status & (1 << offset));
113 }
114 mutex_unlock(&mcp->lock);
115 return status;
116}
117
118static int __mcp23s08_set(struct mcp23s08 *mcp, unsigned mask, int value)
119{
120 u8 olat = mcp->cache[MCP_OLAT];
121
122 if (value)
123 olat |= mask;
124 else
125 olat &= ~mask;
126 mcp->cache[MCP_OLAT] = olat;
127 return mcp23s08_write(mcp, MCP_OLAT, olat);
128}
129
130static void mcp23s08_set(struct gpio_chip *chip, unsigned offset, int value)
131{
132 struct mcp23s08 *mcp = container_of(chip, struct mcp23s08, chip);
133 u8 mask = 1 << offset;
134
135 mutex_lock(&mcp->lock);
136 __mcp23s08_set(mcp, mask, value);
137 mutex_unlock(&mcp->lock);
138}
139
140static int
141mcp23s08_direction_output(struct gpio_chip *chip, unsigned offset, int value)
142{
143 struct mcp23s08 *mcp = container_of(chip, struct mcp23s08, chip);
144 u8 mask = 1 << offset;
145 int status;
146
147 mutex_lock(&mcp->lock);
148 status = __mcp23s08_set(mcp, mask, value);
149 if (status == 0) {
150 mcp->cache[MCP_IODIR] &= ~mask;
151 status = mcp23s08_write(mcp, MCP_IODIR, mcp->cache[MCP_IODIR]);
152 }
153 mutex_unlock(&mcp->lock);
154 return status;
155}
156
157/*----------------------------------------------------------------------*/
158
159#ifdef CONFIG_DEBUG_FS
160
161#include <linux/seq_file.h>
162
163/*
164 * This shows more info than the generic gpio dump code:
165 * pullups, deglitching, open drain drive.
166 */
167static void mcp23s08_dbg_show(struct seq_file *s, struct gpio_chip *chip)
168{
169 struct mcp23s08 *mcp;
170 char bank;
171 unsigned t;
172 unsigned mask;
173
174 mcp = container_of(chip, struct mcp23s08, chip);
175
176 /* NOTE: we only handle one bank for now ... */
177 bank = '0' + ((mcp->addr >> 1) & 0x3);
178
179 mutex_lock(&mcp->lock);
180 t = mcp23s08_read_regs(mcp, 0, mcp->cache, sizeof mcp->cache);
181 if (t < 0) {
182 seq_printf(s, " I/O ERROR %d\n", t);
183 goto done;
184 }
185
186 for (t = 0, mask = 1; t < 8; t++, mask <<= 1) {
187 const char *label;
188
189 label = gpiochip_is_requested(chip, t);
190 if (!label)
191 continue;
192
193 seq_printf(s, " gpio-%-3d P%c.%d (%-12s) %s %s %s",
194 chip->base + t, bank, t, label,
195 (mcp->cache[MCP_IODIR] & mask) ? "in " : "out",
196 (mcp->cache[MCP_GPIO] & mask) ? "hi" : "lo",
197 (mcp->cache[MCP_GPPU] & mask) ? " " : "up");
198 /* NOTE: ignoring the irq-related registers */
199 seq_printf(s, "\n");
200 }
201done:
202 mutex_unlock(&mcp->lock);
203}
204
205#else
206#define mcp23s08_dbg_show NULL
207#endif
208
209/*----------------------------------------------------------------------*/
210
211static int mcp23s08_probe(struct spi_device *spi)
212{
213 struct mcp23s08 *mcp;
214 struct mcp23s08_platform_data *pdata;
215 int status;
216 int do_update = 0;
217
218 pdata = spi->dev.platform_data;
219 if (!pdata || pdata->slave > 3 || !pdata->base)
220 return -ENODEV;
221
222 mcp = kzalloc(sizeof *mcp, GFP_KERNEL);
223 if (!mcp)
224 return -ENOMEM;
225
226 mutex_init(&mcp->lock);
227
228 mcp->spi = spi;
229 mcp->addr = 0x40 | (pdata->slave << 1);
230
231 mcp->chip.label = "mcp23s08",
232
233 mcp->chip.direction_input = mcp23s08_direction_input;
234 mcp->chip.get = mcp23s08_get;
235 mcp->chip.direction_output = mcp23s08_direction_output;
236 mcp->chip.set = mcp23s08_set;
237 mcp->chip.dbg_show = mcp23s08_dbg_show;
238
239 mcp->chip.base = pdata->base;
240 mcp->chip.ngpio = 8;
241 mcp->chip.can_sleep = 1;
242
243 spi_set_drvdata(spi, mcp);
244
245 /* verify MCP_IOCON.SEQOP = 0, so sequential reads work */
246 status = mcp23s08_read(mcp, MCP_IOCON);
247 if (status < 0)
248 goto fail;
249 if (status & IOCON_SEQOP) {
250 status &= ~IOCON_SEQOP;
251 status = mcp23s08_write(mcp, MCP_IOCON, (u8) status);
252 if (status < 0)
253 goto fail;
254 }
255
256 /* configure ~100K pullups */
257 status = mcp23s08_write(mcp, MCP_GPPU, pdata->pullups);
258 if (status < 0)
259 goto fail;
260
261 status = mcp23s08_read_regs(mcp, 0, mcp->cache, sizeof mcp->cache);
262 if (status < 0)
263 goto fail;
264
265 /* disable inverter on input */
266 if (mcp->cache[MCP_IPOL] != 0) {
267 mcp->cache[MCP_IPOL] = 0;
268 do_update = 1;
269 }
270
271 /* disable irqs */
272 if (mcp->cache[MCP_GPINTEN] != 0) {
273 mcp->cache[MCP_GPINTEN] = 0;
274 do_update = 1;
275 }
276
277 if (do_update) {
278 u8 tx[4];
279
280 tx[0] = mcp->addr;
281 tx[1] = MCP_IPOL;
282 memcpy(&tx[2], &mcp->cache[MCP_IPOL], sizeof(tx) - 2);
283 status = spi_write_then_read(mcp->spi, tx, sizeof tx, NULL, 0);
284
285 /* FIXME check status... */
286 }
287
288 status = gpiochip_add(&mcp->chip);
289
290 /* NOTE: these chips have a relatively sane IRQ framework, with
291 * per-signal masking and level/edge triggering. It's not yet
292 * handled here...
293 */
294
295 if (pdata->setup) {
296 status = pdata->setup(spi, mcp->chip.base,
297 mcp->chip.ngpio, pdata->context);
298 if (status < 0)
299 dev_dbg(&spi->dev, "setup --> %d\n", status);
300 }
301
302 return 0;
303
304fail:
305 kfree(mcp);
306 return status;
307}
308
309static int mcp23s08_remove(struct spi_device *spi)
310{
311 struct mcp23s08 *mcp = spi_get_drvdata(spi);
312 struct mcp23s08_platform_data *pdata = spi->dev.platform_data;
313 int status = 0;
314
315 if (pdata->teardown) {
316 status = pdata->teardown(spi,
317 mcp->chip.base, mcp->chip.ngpio,
318 pdata->context);
319 if (status < 0) {
320 dev_err(&spi->dev, "%s --> %d\n", "teardown", status);
321 return status;
322 }
323 }
324
325 status = gpiochip_remove(&mcp->chip);
326 if (status == 0)
327 kfree(mcp);
328 else
329 dev_err(&spi->dev, "%s --> %d\n", "remove", status);
330 return status;
331}
332
333static struct spi_driver mcp23s08_driver = {
334 .probe = mcp23s08_probe,
335 .remove = mcp23s08_remove,
336 .driver = {
337 .name = "mcp23s08",
338 .owner = THIS_MODULE,
339 },
340};
341
342/*----------------------------------------------------------------------*/
343
344static int __init mcp23s08_init(void)
345{
346 return spi_register_driver(&mcp23s08_driver);
347}
348module_init(mcp23s08_init);
349
350static void __exit mcp23s08_exit(void)
351{
352 spi_unregister_driver(&mcp23s08_driver);
353}
354module_exit(mcp23s08_exit);
355
356MODULE_LICENSE("GPL");
357