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linux-next/drivers/gpio/mcp23s08.c
Peter Korsgaard 0b7bb77fd5 gpio/mcp23s08: support mcp23s17 variant 
mpc23s17 is very similar to the mcp23s08, except that registers are 16bit
wide, so extend the interface to work with both variants.

The s17 variant also has an additional address pin, so adjust platform
data structure to support up to 8 devices per SPI chipselect.

Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2011-03-12 01:26:34 -07:00

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/*
* mcp23s08.c - SPI gpio expander driver
*/
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/workqueue.h>
#include <linux/mutex.h>
#include <linux/gpio.h>
#include <linux/spi/spi.h>
#include <linux/spi/mcp23s08.h>
#include <linux/slab.h>
#include <asm/byteorder.h>
/**
* MCP types supported by driver
*/
#define MCP_TYPE_S08 0
#define MCP_TYPE_S17 1
/* Registers are all 8 bits wide.
*
* The mcp23s17 has twice as many bits, and can be configured to work
* with either 16 bit registers or with two adjacent 8 bit banks.
*
* Also, there are I2C versions of both chips.
*/
#define MCP_IODIR 0x00 /* init/reset: all ones */
#define MCP_IPOL 0x01
#define MCP_GPINTEN 0x02
#define MCP_DEFVAL 0x03
#define MCP_INTCON 0x04
#define MCP_IOCON 0x05
# define IOCON_SEQOP (1 << 5)
# define IOCON_HAEN (1 << 3)
# define IOCON_ODR (1 << 2)
# define IOCON_INTPOL (1 << 1)
#define MCP_GPPU 0x06
#define MCP_INTF 0x07
#define MCP_INTCAP 0x08
#define MCP_GPIO 0x09
#define MCP_OLAT 0x0a
struct mcp23s08;
struct mcp23s08_ops {
int (*read)(struct mcp23s08 *mcp, unsigned reg);
int (*write)(struct mcp23s08 *mcp, unsigned reg, unsigned val);
int (*read_regs)(struct mcp23s08 *mcp, unsigned reg,
u16 *vals, unsigned n);
};
struct mcp23s08 {
struct spi_device *spi;
u8 addr;
u16 cache[11];
/* lock protects the cached values */
struct mutex lock;
struct gpio_chip chip;
struct work_struct work;
const struct mcp23s08_ops *ops;
};
/* A given spi_device can represent up to eight mcp23sxx chips
* sharing the same chipselect but using different addresses
* (e.g. chips #0 and #3 might be populated, but not #1 or $2).
* Driver data holds all the per-chip data.
*/
struct mcp23s08_driver_data {
unsigned ngpio;
struct mcp23s08 *mcp[8];
struct mcp23s08 chip[];
};
static int mcp23s08_read(struct mcp23s08 *mcp, unsigned reg)
{
u8 tx[2], rx[1];
int status;
tx[0] = mcp->addr | 0x01;
tx[1] = reg;
status = spi_write_then_read(mcp->spi, tx, sizeof tx, rx, sizeof rx);
return (status < 0) ? status : rx[0];
}
static int mcp23s08_write(struct mcp23s08 *mcp, unsigned reg, unsigned val)
{
u8 tx[3];
tx[0] = mcp->addr;
tx[1] = reg;
tx[2] = val;
return spi_write_then_read(mcp->spi, tx, sizeof tx, NULL, 0);
}
static int
mcp23s08_read_regs(struct mcp23s08 *mcp, unsigned reg, u16 *vals, unsigned n)
{
u8 tx[2], *tmp;
int status;
if ((n + reg) > sizeof mcp->cache)
return -EINVAL;
tx[0] = mcp->addr | 0x01;
tx[1] = reg;
tmp = (u8 *)vals;
status = spi_write_then_read(mcp->spi, tx, sizeof tx, tmp, n);
if (status >= 0) {
while (n--)
vals[n] = tmp[n]; /* expand to 16bit */
}
return status;
}
static int mcp23s17_read(struct mcp23s08 *mcp, unsigned reg)
{
u8 tx[2], rx[2];
int status;
tx[0] = mcp->addr | 0x01;
tx[1] = reg << 1;
status = spi_write_then_read(mcp->spi, tx, sizeof tx, rx, sizeof rx);
return (status < 0) ? status : (rx[0] | (rx[1] << 8));
}
static int mcp23s17_write(struct mcp23s08 *mcp, unsigned reg, unsigned val)
{
u8 tx[4];
tx[0] = mcp->addr;
tx[1] = reg << 1;
tx[2] = val;
tx[3] = val >> 8;
return spi_write_then_read(mcp->spi, tx, sizeof tx, NULL, 0);
}
static int
mcp23s17_read_regs(struct mcp23s08 *mcp, unsigned reg, u16 *vals, unsigned n)
{
u8 tx[2];
int status;
if ((n + reg) > sizeof mcp->cache)
return -EINVAL;
tx[0] = mcp->addr | 0x01;
tx[1] = reg << 1;
status = spi_write_then_read(mcp->spi, tx, sizeof tx,
(u8 *)vals, n * 2);
if (status >= 0) {
while (n--)
vals[n] = __le16_to_cpu((__le16)vals[n]);
}
return status;
}
static const struct mcp23s08_ops mcp23s08_ops = {
.read = mcp23s08_read,
.write = mcp23s08_write,
.read_regs = mcp23s08_read_regs,
};
static const struct mcp23s08_ops mcp23s17_ops = {
.read = mcp23s17_read,
.write = mcp23s17_write,
.read_regs = mcp23s17_read_regs,
};
/*----------------------------------------------------------------------*/
static int mcp23s08_direction_input(struct gpio_chip *chip, unsigned offset)
{
struct mcp23s08 *mcp = container_of(chip, struct mcp23s08, chip);
int status;
mutex_lock(&mcp->lock);
mcp->cache[MCP_IODIR] |= (1 << offset);
status = mcp->ops->write(mcp, MCP_IODIR, mcp->cache[MCP_IODIR]);
mutex_unlock(&mcp->lock);
return status;
}
static int mcp23s08_get(struct gpio_chip *chip, unsigned offset)
{
struct mcp23s08 *mcp = container_of(chip, struct mcp23s08, chip);
int status;
mutex_lock(&mcp->lock);
/* REVISIT reading this clears any IRQ ... */
status = mcp->ops->read(mcp, MCP_GPIO);
if (status < 0)
status = 0;
else {
mcp->cache[MCP_GPIO] = status;
status = !!(status & (1 << offset));
}
mutex_unlock(&mcp->lock);
return status;
}
static int __mcp23s08_set(struct mcp23s08 *mcp, unsigned mask, int value)
{
unsigned olat = mcp->cache[MCP_OLAT];
if (value)
olat |= mask;
else
olat &= ~mask;
mcp->cache[MCP_OLAT] = olat;
return mcp->ops->write(mcp, MCP_OLAT, olat);
}
static void mcp23s08_set(struct gpio_chip *chip, unsigned offset, int value)
{
struct mcp23s08 *mcp = container_of(chip, struct mcp23s08, chip);
unsigned mask = 1 << offset;
mutex_lock(&mcp->lock);
__mcp23s08_set(mcp, mask, value);
mutex_unlock(&mcp->lock);
}
static int
mcp23s08_direction_output(struct gpio_chip *chip, unsigned offset, int value)
{
struct mcp23s08 *mcp = container_of(chip, struct mcp23s08, chip);
unsigned mask = 1 << offset;
int status;
mutex_lock(&mcp->lock);
status = __mcp23s08_set(mcp, mask, value);
if (status == 0) {
mcp->cache[MCP_IODIR] &= ~mask;
status = mcp->ops->write(mcp, MCP_IODIR, mcp->cache[MCP_IODIR]);
}
mutex_unlock(&mcp->lock);
return status;
}
/*----------------------------------------------------------------------*/
#ifdef CONFIG_DEBUG_FS
#include <linux/seq_file.h>
/*
* This shows more info than the generic gpio dump code:
* pullups, deglitching, open drain drive.
*/
static void mcp23s08_dbg_show(struct seq_file *s, struct gpio_chip *chip)
{
struct mcp23s08 *mcp;
char bank;
int t;
unsigned mask;
mcp = container_of(chip, struct mcp23s08, chip);
/* NOTE: we only handle one bank for now ... */
bank = '0' + ((mcp->addr >> 1) & 0x7);
mutex_lock(&mcp->lock);
t = mcp->ops->read_regs(mcp, 0, mcp->cache, ARRAY_SIZE(mcp->cache));
if (t < 0) {
seq_printf(s, " I/O ERROR %d\n", t);
goto done;
}
for (t = 0, mask = 1; t < chip->ngpio; t++, mask <<= 1) {
const char *label;
label = gpiochip_is_requested(chip, t);
if (!label)
continue;
seq_printf(s, " gpio-%-3d P%c.%d (%-12s) %s %s %s",
chip->base + t, bank, t, label,
(mcp->cache[MCP_IODIR] & mask) ? "in " : "out",
(mcp->cache[MCP_GPIO] & mask) ? "hi" : "lo",
(mcp->cache[MCP_GPPU] & mask) ? " " : "up");
/* NOTE: ignoring the irq-related registers */
seq_printf(s, "\n");
}
done:
mutex_unlock(&mcp->lock);
}
#else
#define mcp23s08_dbg_show NULL
#endif
/*----------------------------------------------------------------------*/
static int mcp23s08_probe_one(struct spi_device *spi, unsigned addr,
unsigned type, unsigned base, unsigned pullups)
{
struct mcp23s08_driver_data *data = spi_get_drvdata(spi);
struct mcp23s08 *mcp = data->mcp[addr];
int status;
mutex_init(&mcp->lock);
mcp->spi = spi;
mcp->addr = 0x40 | (addr << 1);
mcp->chip.direction_input = mcp23s08_direction_input;
mcp->chip.get = mcp23s08_get;
mcp->chip.direction_output = mcp23s08_direction_output;
mcp->chip.set = mcp23s08_set;
mcp->chip.dbg_show = mcp23s08_dbg_show;
if (type == MCP_TYPE_S17) {
mcp->ops = &mcp23s17_ops;
mcp->chip.ngpio = 16;
mcp->chip.label = "mcp23s17";
} else {
mcp->ops = &mcp23s08_ops;
mcp->chip.ngpio = 8;
mcp->chip.label = "mcp23s08";
}
mcp->chip.base = base;
mcp->chip.can_sleep = 1;
mcp->chip.dev = &spi->dev;
mcp->chip.owner = THIS_MODULE;
/* verify MCP_IOCON.SEQOP = 0, so sequential reads work,
* and MCP_IOCON.HAEN = 1, so we work with all chips.
*/
status = mcp->ops->read(mcp, MCP_IOCON);
if (status < 0)
goto fail;
if ((status & IOCON_SEQOP) || !(status & IOCON_HAEN)) {
/* mcp23s17 has IOCON twice, make sure they are in sync */
status &= ~(IOCON_SEQOP | (IOCON_SEQOP << 8));
status |= IOCON_HAEN | (IOCON_HAEN << 8);
status = mcp->ops->write(mcp, MCP_IOCON, status);
if (status < 0)
goto fail;
}
/* configure ~100K pullups */
status = mcp->ops->write(mcp, MCP_GPPU, pullups);
if (status < 0)
goto fail;
status = mcp->ops->read_regs(mcp, 0, mcp->cache, ARRAY_SIZE(mcp->cache));
if (status < 0)
goto fail;
/* disable inverter on input */
if (mcp->cache[MCP_IPOL] != 0) {
mcp->cache[MCP_IPOL] = 0;
status = mcp->ops->write(mcp, MCP_IPOL, 0);
if (status < 0)
goto fail;
}
/* disable irqs */
if (mcp->cache[MCP_GPINTEN] != 0) {
mcp->cache[MCP_GPINTEN] = 0;
status = mcp->ops->write(mcp, MCP_GPINTEN, 0);
if (status < 0)
goto fail;
}
status = gpiochip_add(&mcp->chip);
fail:
if (status < 0)
dev_dbg(&spi->dev, "can't setup chip %d, --> %d\n",
addr, status);
return status;
}
static int mcp23s08_probe(struct spi_device *spi)
{
struct mcp23s08_platform_data *pdata;
unsigned addr;
unsigned chips = 0;
struct mcp23s08_driver_data *data;
int status, type;
unsigned base;
type = spi_get_device_id(spi)->driver_data;
pdata = spi->dev.platform_data;
if (!pdata || !gpio_is_valid(pdata->base)) {
dev_dbg(&spi->dev, "invalid or missing platform data\n");
return -EINVAL;
}
for (addr = 0; addr < ARRAY_SIZE(pdata->chip); addr++) {
if (!pdata->chip[addr].is_present)
continue;
chips++;
if ((type == MCP_TYPE_S08) && (addr > 3)) {
dev_err(&spi->dev,
"mcp23s08 only supports address 0..3\n");
return -EINVAL;
}
}
if (!chips)
return -ENODEV;
data = kzalloc(sizeof *data + chips * sizeof(struct mcp23s08),
GFP_KERNEL);
if (!data)
return -ENOMEM;
spi_set_drvdata(spi, data);
base = pdata->base;
for (addr = 0; addr < ARRAY_SIZE(pdata->chip); addr++) {
if (!pdata->chip[addr].is_present)
continue;
chips--;
data->mcp[addr] = &data->chip[chips];
status = mcp23s08_probe_one(spi, addr, type, base,
pdata->chip[addr].pullups);
if (status < 0)
goto fail;
base += (type == MCP_TYPE_S17) ? 16 : 8;
}
data->ngpio = base - pdata->base;
/* NOTE: these chips have a relatively sane IRQ framework, with
* per-signal masking and level/edge triggering. It's not yet
* handled here...
*/
if (pdata->setup) {
status = pdata->setup(spi,
pdata->base, data->ngpio,
pdata->context);
if (status < 0)
dev_dbg(&spi->dev, "setup --> %d\n", status);
}
return 0;
fail:
for (addr = 0; addr < ARRAY_SIZE(data->mcp); addr++) {
int tmp;
if (!data->mcp[addr])
continue;
tmp = gpiochip_remove(&data->mcp[addr]->chip);
if (tmp < 0)
dev_err(&spi->dev, "%s --> %d\n", "remove", tmp);
}
kfree(data);
return status;
}
static int mcp23s08_remove(struct spi_device *spi)
{
struct mcp23s08_driver_data *data = spi_get_drvdata(spi);
struct mcp23s08_platform_data *pdata = spi->dev.platform_data;
unsigned addr;
int status = 0;
if (pdata->teardown) {
status = pdata->teardown(spi,
pdata->base, data->ngpio,
pdata->context);
if (status < 0) {
dev_err(&spi->dev, "%s --> %d\n", "teardown", status);
return status;
}
}
for (addr = 0; addr < ARRAY_SIZE(data->mcp); addr++) {
int tmp;
if (!data->mcp[addr])
continue;
tmp = gpiochip_remove(&data->mcp[addr]->chip);
if (tmp < 0) {
dev_err(&spi->dev, "%s --> %d\n", "remove", tmp);
status = tmp;
}
}
if (status == 0)
kfree(data);
return status;
}
static const struct spi_device_id mcp23s08_ids[] = {
{ "mcp23s08", MCP_TYPE_S08 },
{ "mcp23s17", MCP_TYPE_S17 },
{ },
};
MODULE_DEVICE_TABLE(spi, mcp23s08_ids);
static struct spi_driver mcp23s08_driver = {
.probe = mcp23s08_probe,
.remove = mcp23s08_remove,
.id_table = mcp23s08_ids,
.driver = {
.name = "mcp23s08",
.owner = THIS_MODULE,
},
};
/*----------------------------------------------------------------------*/
static int __init mcp23s08_init(void)
{
return spi_register_driver(&mcp23s08_driver);
}
/* register after spi postcore initcall and before
* subsys initcalls that may rely on these GPIOs
*/
subsys_initcall(mcp23s08_init);
static void __exit mcp23s08_exit(void)
{
spi_unregister_driver(&mcp23s08_driver);
}
module_exit(mcp23s08_exit);
MODULE_LICENSE("GPL");
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