2 * MCP23S08 SPI gpio expander driver
5 #include <linux/kernel.h>
6 #include <linux/device.h>
7 #include <linux/mutex.h>
8 #include <linux/gpio.h>
9 #include <linux/spi/spi.h>
10 #include <linux/spi/mcp23s08.h>
11 #include <linux/slab.h>
12 #include <asm/byteorder.h>
15 * MCP types supported by driver
17 #define MCP_TYPE_S08 0
18 #define MCP_TYPE_S17 1
20 /* Registers are all 8 bits wide.
22 * The mcp23s17 has twice as many bits, and can be configured to work
23 * with either 16 bit registers or with two adjacent 8 bit banks.
25 * Also, there are I2C versions of both chips.
27 #define MCP_IODIR 0x00 /* init/reset: all ones */
29 #define MCP_GPINTEN 0x02
30 #define MCP_DEFVAL 0x03
31 #define MCP_INTCON 0x04
32 #define MCP_IOCON 0x05
33 # define IOCON_SEQOP (1 << 5)
34 # define IOCON_HAEN (1 << 3)
35 # define IOCON_ODR (1 << 2)
36 # define IOCON_INTPOL (1 << 1)
39 #define MCP_INTCAP 0x08
46 int (*read)(struct mcp23s08 *mcp, unsigned reg);
47 int (*write)(struct mcp23s08 *mcp, unsigned reg, unsigned val);
48 int (*read_regs)(struct mcp23s08 *mcp, unsigned reg,
49 u16 *vals, unsigned n);
53 struct spi_device *spi;
57 /* lock protects the cached values */
60 struct gpio_chip chip;
62 const struct mcp23s08_ops *ops;
65 /* A given spi_device can represent up to eight mcp23sxx chips
66 * sharing the same chipselect but using different addresses
67 * (e.g. chips #0 and #3 might be populated, but not #1 or $2).
68 * Driver data holds all the per-chip data.
70 struct mcp23s08_driver_data {
72 struct mcp23s08 *mcp[8];
73 struct mcp23s08 chip[];
76 static int mcp23s08_read(struct mcp23s08 *mcp, unsigned reg)
81 tx[0] = mcp->addr | 0x01;
83 status = spi_write_then_read(mcp->spi, tx, sizeof tx, rx, sizeof rx);
84 return (status < 0) ? status : rx[0];
87 static int mcp23s08_write(struct mcp23s08 *mcp, unsigned reg, unsigned val)
94 return spi_write_then_read(mcp->spi, tx, sizeof tx, NULL, 0);
98 mcp23s08_read_regs(struct mcp23s08 *mcp, unsigned reg, u16 *vals, unsigned n)
103 if ((n + reg) > sizeof mcp->cache)
105 tx[0] = mcp->addr | 0x01;
109 status = spi_write_then_read(mcp->spi, tx, sizeof tx, tmp, n);
112 vals[n] = tmp[n]; /* expand to 16bit */
117 static int mcp23s17_read(struct mcp23s08 *mcp, unsigned reg)
122 tx[0] = mcp->addr | 0x01;
124 status = spi_write_then_read(mcp->spi, tx, sizeof tx, rx, sizeof rx);
125 return (status < 0) ? status : (rx[0] | (rx[1] << 8));
128 static int mcp23s17_write(struct mcp23s08 *mcp, unsigned reg, unsigned val)
136 return spi_write_then_read(mcp->spi, tx, sizeof tx, NULL, 0);
140 mcp23s17_read_regs(struct mcp23s08 *mcp, unsigned reg, u16 *vals, unsigned n)
145 if ((n + reg) > sizeof mcp->cache)
147 tx[0] = mcp->addr | 0x01;
150 status = spi_write_then_read(mcp->spi, tx, sizeof tx,
154 vals[n] = __le16_to_cpu((__le16)vals[n]);
160 static const struct mcp23s08_ops mcp23s08_ops = {
161 .read = mcp23s08_read,
162 .write = mcp23s08_write,
163 .read_regs = mcp23s08_read_regs,
166 static const struct mcp23s08_ops mcp23s17_ops = {
167 .read = mcp23s17_read,
168 .write = mcp23s17_write,
169 .read_regs = mcp23s17_read_regs,
173 /*----------------------------------------------------------------------*/
175 static int mcp23s08_direction_input(struct gpio_chip *chip, unsigned offset)
177 struct mcp23s08 *mcp = container_of(chip, struct mcp23s08, chip);
180 mutex_lock(&mcp->lock);
181 mcp->cache[MCP_IODIR] |= (1 << offset);
182 status = mcp->ops->write(mcp, MCP_IODIR, mcp->cache[MCP_IODIR]);
183 mutex_unlock(&mcp->lock);
187 static int mcp23s08_get(struct gpio_chip *chip, unsigned offset)
189 struct mcp23s08 *mcp = container_of(chip, struct mcp23s08, chip);
192 mutex_lock(&mcp->lock);
194 /* REVISIT reading this clears any IRQ ... */
195 status = mcp->ops->read(mcp, MCP_GPIO);
199 mcp->cache[MCP_GPIO] = status;
200 status = !!(status & (1 << offset));
202 mutex_unlock(&mcp->lock);
206 static int __mcp23s08_set(struct mcp23s08 *mcp, unsigned mask, int value)
208 unsigned olat = mcp->cache[MCP_OLAT];
214 mcp->cache[MCP_OLAT] = olat;
215 return mcp->ops->write(mcp, MCP_OLAT, olat);
218 static void mcp23s08_set(struct gpio_chip *chip, unsigned offset, int value)
220 struct mcp23s08 *mcp = container_of(chip, struct mcp23s08, chip);
221 unsigned mask = 1 << offset;
223 mutex_lock(&mcp->lock);
224 __mcp23s08_set(mcp, mask, value);
225 mutex_unlock(&mcp->lock);
229 mcp23s08_direction_output(struct gpio_chip *chip, unsigned offset, int value)
231 struct mcp23s08 *mcp = container_of(chip, struct mcp23s08, chip);
232 unsigned mask = 1 << offset;
235 mutex_lock(&mcp->lock);
236 status = __mcp23s08_set(mcp, mask, value);
238 mcp->cache[MCP_IODIR] &= ~mask;
239 status = mcp->ops->write(mcp, MCP_IODIR, mcp->cache[MCP_IODIR]);
241 mutex_unlock(&mcp->lock);
245 /*----------------------------------------------------------------------*/
247 #ifdef CONFIG_DEBUG_FS
249 #include <linux/seq_file.h>
252 * This shows more info than the generic gpio dump code:
253 * pullups, deglitching, open drain drive.
255 static void mcp23s08_dbg_show(struct seq_file *s, struct gpio_chip *chip)
257 struct mcp23s08 *mcp;
262 mcp = container_of(chip, struct mcp23s08, chip);
264 /* NOTE: we only handle one bank for now ... */
265 bank = '0' + ((mcp->addr >> 1) & 0x7);
267 mutex_lock(&mcp->lock);
268 t = mcp->ops->read_regs(mcp, 0, mcp->cache, ARRAY_SIZE(mcp->cache));
270 seq_printf(s, " I/O ERROR %d\n", t);
274 for (t = 0, mask = 1; t < chip->ngpio; t++, mask <<= 1) {
277 label = gpiochip_is_requested(chip, t);
281 seq_printf(s, " gpio-%-3d P%c.%d (%-12s) %s %s %s",
282 chip->base + t, bank, t, label,
283 (mcp->cache[MCP_IODIR] & mask) ? "in " : "out",
284 (mcp->cache[MCP_GPIO] & mask) ? "hi" : "lo",
285 (mcp->cache[MCP_GPPU] & mask) ? " " : "up");
286 /* NOTE: ignoring the irq-related registers */
290 mutex_unlock(&mcp->lock);
294 #define mcp23s08_dbg_show NULL
297 /*----------------------------------------------------------------------*/
299 static int mcp23s08_probe_one(struct spi_device *spi, unsigned addr,
300 unsigned type, unsigned base, unsigned pullups)
302 struct mcp23s08_driver_data *data = spi_get_drvdata(spi);
303 struct mcp23s08 *mcp = data->mcp[addr];
306 mutex_init(&mcp->lock);
309 mcp->addr = 0x40 | (addr << 1);
311 mcp->chip.direction_input = mcp23s08_direction_input;
312 mcp->chip.get = mcp23s08_get;
313 mcp->chip.direction_output = mcp23s08_direction_output;
314 mcp->chip.set = mcp23s08_set;
315 mcp->chip.dbg_show = mcp23s08_dbg_show;
317 if (type == MCP_TYPE_S17) {
318 mcp->ops = &mcp23s17_ops;
319 mcp->chip.ngpio = 16;
320 mcp->chip.label = "mcp23s17";
322 mcp->ops = &mcp23s08_ops;
324 mcp->chip.label = "mcp23s08";
326 mcp->chip.base = base;
327 mcp->chip.can_sleep = 1;
328 mcp->chip.dev = &spi->dev;
329 mcp->chip.owner = THIS_MODULE;
331 /* verify MCP_IOCON.SEQOP = 0, so sequential reads work,
332 * and MCP_IOCON.HAEN = 1, so we work with all chips.
334 status = mcp->ops->read(mcp, MCP_IOCON);
337 if ((status & IOCON_SEQOP) || !(status & IOCON_HAEN)) {
338 /* mcp23s17 has IOCON twice, make sure they are in sync */
339 status &= ~(IOCON_SEQOP | (IOCON_SEQOP << 8));
340 status |= IOCON_HAEN | (IOCON_HAEN << 8);
341 status = mcp->ops->write(mcp, MCP_IOCON, status);
346 /* configure ~100K pullups */
347 status = mcp->ops->write(mcp, MCP_GPPU, pullups);
351 status = mcp->ops->read_regs(mcp, 0, mcp->cache, ARRAY_SIZE(mcp->cache));
355 /* disable inverter on input */
356 if (mcp->cache[MCP_IPOL] != 0) {
357 mcp->cache[MCP_IPOL] = 0;
358 status = mcp->ops->write(mcp, MCP_IPOL, 0);
364 if (mcp->cache[MCP_GPINTEN] != 0) {
365 mcp->cache[MCP_GPINTEN] = 0;
366 status = mcp->ops->write(mcp, MCP_GPINTEN, 0);
371 status = gpiochip_add(&mcp->chip);
374 dev_dbg(&spi->dev, "can't setup chip %d, --> %d\n",
379 static int mcp23s08_probe(struct spi_device *spi)
381 struct mcp23s08_platform_data *pdata;
384 struct mcp23s08_driver_data *data;
388 type = spi_get_device_id(spi)->driver_data;
390 pdata = spi->dev.platform_data;
391 if (!pdata || !gpio_is_valid(pdata->base)) {
392 dev_dbg(&spi->dev, "invalid or missing platform data\n");
396 for (addr = 0; addr < ARRAY_SIZE(pdata->chip); addr++) {
397 if (!pdata->chip[addr].is_present)
400 if ((type == MCP_TYPE_S08) && (addr > 3)) {
402 "mcp23s08 only supports address 0..3\n");
409 data = kzalloc(sizeof *data + chips * sizeof(struct mcp23s08),
413 spi_set_drvdata(spi, data);
416 for (addr = 0; addr < ARRAY_SIZE(pdata->chip); addr++) {
417 if (!pdata->chip[addr].is_present)
420 data->mcp[addr] = &data->chip[chips];
421 status = mcp23s08_probe_one(spi, addr, type, base,
422 pdata->chip[addr].pullups);
426 base += (type == MCP_TYPE_S17) ? 16 : 8;
428 data->ngpio = base - pdata->base;
430 /* NOTE: these chips have a relatively sane IRQ framework, with
431 * per-signal masking and level/edge triggering. It's not yet
438 for (addr = 0; addr < ARRAY_SIZE(data->mcp); addr++) {
441 if (!data->mcp[addr])
443 tmp = gpiochip_remove(&data->mcp[addr]->chip);
445 dev_err(&spi->dev, "%s --> %d\n", "remove", tmp);
451 static int mcp23s08_remove(struct spi_device *spi)
453 struct mcp23s08_driver_data *data = spi_get_drvdata(spi);
457 for (addr = 0; addr < ARRAY_SIZE(data->mcp); addr++) {
460 if (!data->mcp[addr])
463 tmp = gpiochip_remove(&data->mcp[addr]->chip);
465 dev_err(&spi->dev, "%s --> %d\n", "remove", tmp);
474 static const struct spi_device_id mcp23s08_ids[] = {
475 { "mcp23s08", MCP_TYPE_S08 },
476 { "mcp23s17", MCP_TYPE_S17 },
479 MODULE_DEVICE_TABLE(spi, mcp23s08_ids);
481 static struct spi_driver mcp23s08_driver = {
482 .probe = mcp23s08_probe,
483 .remove = mcp23s08_remove,
484 .id_table = mcp23s08_ids,
487 .owner = THIS_MODULE,
491 /*----------------------------------------------------------------------*/
493 static int __init mcp23s08_init(void)
495 return spi_register_driver(&mcp23s08_driver);
497 /* register after spi postcore initcall and before
498 * subsys initcalls that may rely on these GPIOs
500 subsys_initcall(mcp23s08_init);
502 static void __exit mcp23s08_exit(void)
504 spi_unregister_driver(&mcp23s08_driver);
506 module_exit(mcp23s08_exit);
508 MODULE_LICENSE("GPL");