mcp23s08 spi gpio expander support
Basic driver for 8-bit SPI based MCP23S08 GPIO expander, without support for IRQs or the shared chipselect mechanism. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Cc: Jean Delvare <khali@linux-fr.org> Cc: Eric Miao <eric.miao@marvell.com> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Haavard Skinnemoen <hskinnemoen@atmel.com> Cc: Philipp Zabel <philipp.zabel@gmail.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Ben Gardner <bgardner@wabtec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
David Brownell
Linus Torvalds
parent
15fae37d9f
commit
e58b9e2762
|
|
@ -52,4 +52,11 @@ config GPIO_PCF857X
|
|||
|
||||
comment "SPI GPIO expanders:"
|
||||
|
||||
config GPIO_MCP23S08
|
||||
tristate "Microchip MCP23S08 I/O expander"
|
||||
depends on SPI_MASTER
|
||||
help
|
||||
SPI driver for Microchip MCP23S08 I/O expander. This provides
|
||||
a GPIO interface supporting inputs and outputs.
|
||||
|
||||
endmenu
|
||||
|
|
|
|||
|
|
@ -4,4 +4,5 @@ ccflags-$(CONFIG_DEBUG_GPIO) += -DDEBUG
|
|||
|
||||
obj-$(CONFIG_HAVE_GPIO_LIB) += gpiolib.o
|
||||
|
||||
obj-$(CONFIG_GPIO_MCP23S08) += mcp23s08.o
|
||||
obj-$(CONFIG_GPIO_PCF857X) += pcf857x.o
|
||||
|
|
|
|||
|
|
@ -0,0 +1,357 @@
|
|||
/*
|
||||
* mcp23s08.c - SPI gpio expander driver
|
||||
*/
|
||||
|
||||
#include <linux/kernel.h>
|
||||
#include <linux/device.h>
|
||||
#include <linux/workqueue.h>
|
||||
#include <linux/mutex.h>
|
||||
|
||||
#include <linux/spi/spi.h>
|
||||
#include <linux/spi/mcp23s08.h>
|
||||
|
||||
#include <asm/gpio.h>
|
||||
|
||||
|
||||
/* 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 spi_device *spi;
|
||||
u8 addr;
|
||||
|
||||
/* lock protects the cached values */
|
||||
struct mutex lock;
|
||||
u8 cache[11];
|
||||
|
||||
struct gpio_chip chip;
|
||||
|
||||
struct work_struct work;
|
||||
};
|
||||
|
||||
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, u8 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, u8 *vals, unsigned n)
|
||||
{
|
||||
u8 tx[2];
|
||||
|
||||
if ((n + reg) > sizeof mcp->cache)
|
||||
return -EINVAL;
|
||||
tx[0] = mcp->addr | 0x01;
|
||||
tx[1] = reg;
|
||||
return spi_write_then_read(mcp->spi, tx, sizeof tx, vals, n);
|
||||
}
|
||||
|
||||
/*----------------------------------------------------------------------*/
|
||||
|
||||
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 = mcp23s08_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 = mcp23s08_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)
|
||||
{
|
||||
u8 olat = mcp->cache[MCP_OLAT];
|
||||
|
||||
if (value)
|
||||
olat |= mask;
|
||||
else
|
||||
olat &= ~mask;
|
||||
mcp->cache[MCP_OLAT] = olat;
|
||||
return mcp23s08_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);
|
||||
u8 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);
|
||||
u8 mask = 1 << offset;
|
||||
int status;
|
||||
|
||||
mutex_lock(&mcp->lock);
|
||||
status = __mcp23s08_set(mcp, mask, value);
|
||||
if (status == 0) {
|
||||
mcp->cache[MCP_IODIR] &= ~mask;
|
||||
status = mcp23s08_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;
|
||||
unsigned t;
|
||||
unsigned mask;
|
||||
|
||||
mcp = container_of(chip, struct mcp23s08, chip);
|
||||
|
||||
/* NOTE: we only handle one bank for now ... */
|
||||
bank = '0' + ((mcp->addr >> 1) & 0x3);
|
||||
|
||||
mutex_lock(&mcp->lock);
|
||||
t = mcp23s08_read_regs(mcp, 0, mcp->cache, sizeof mcp->cache);
|
||||
if (t < 0) {
|
||||
seq_printf(s, " I/O ERROR %d\n", t);
|
||||
goto done;
|
||||
}
|
||||
|
||||
for (t = 0, mask = 1; t < 8; 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(struct spi_device *spi)
|
||||
{
|
||||
struct mcp23s08 *mcp;
|
||||
struct mcp23s08_platform_data *pdata;
|
||||
int status;
|
||||
int do_update = 0;
|
||||
|
||||
pdata = spi->dev.platform_data;
|
||||
if (!pdata || pdata->slave > 3 || !pdata->base)
|
||||
return -ENODEV;
|
||||
|
||||
mcp = kzalloc(sizeof *mcp, GFP_KERNEL);
|
||||
if (!mcp)
|
||||
return -ENOMEM;
|
||||
|
||||
mutex_init(&mcp->lock);
|
||||
|
||||
mcp->spi = spi;
|
||||
mcp->addr = 0x40 | (pdata->slave << 1);
|
||||
|
||||
mcp->chip.label = "mcp23s08",
|
||||
|
||||
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;
|
||||
|
||||
mcp->chip.base = pdata->base;
|
||||
mcp->chip.ngpio = 8;
|
||||
mcp->chip.can_sleep = 1;
|
||||
|
||||
spi_set_drvdata(spi, mcp);
|
||||
|
||||
/* verify MCP_IOCON.SEQOP = 0, so sequential reads work */
|
||||
status = mcp23s08_read(mcp, MCP_IOCON);
|
||||
if (status < 0)
|
||||
goto fail;
|
||||
if (status & IOCON_SEQOP) {
|
||||
status &= ~IOCON_SEQOP;
|
||||
status = mcp23s08_write(mcp, MCP_IOCON, (u8) status);
|
||||
if (status < 0)
|
||||
goto fail;
|
||||
}
|
||||
|
||||
/* configure ~100K pullups */
|
||||
status = mcp23s08_write(mcp, MCP_GPPU, pdata->pullups);
|
||||
if (status < 0)
|
||||
goto fail;
|
||||
|
||||
status = mcp23s08_read_regs(mcp, 0, mcp->cache, sizeof mcp->cache);
|
||||
if (status < 0)
|
||||
goto fail;
|
||||
|
||||
/* disable inverter on input */
|
||||
if (mcp->cache[MCP_IPOL] != 0) {
|
||||
mcp->cache[MCP_IPOL] = 0;
|
||||
do_update = 1;
|
||||
}
|
||||
|
||||
/* disable irqs */
|
||||
if (mcp->cache[MCP_GPINTEN] != 0) {
|
||||
mcp->cache[MCP_GPINTEN] = 0;
|
||||
do_update = 1;
|
||||
}
|
||||
|
||||
if (do_update) {
|
||||
u8 tx[4];
|
||||
|
||||
tx[0] = mcp->addr;
|
||||
tx[1] = MCP_IPOL;
|
||||
memcpy(&tx[2], &mcp->cache[MCP_IPOL], sizeof(tx) - 2);
|
||||
status = spi_write_then_read(mcp->spi, tx, sizeof tx, NULL, 0);
|
||||
|
||||
/* FIXME check status... */
|
||||
}
|
||||
|
||||
status = gpiochip_add(&mcp->chip);
|
||||
|
||||
/* 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, mcp->chip.base,
|
||||
mcp->chip.ngpio, pdata->context);
|
||||
if (status < 0)
|
||||
dev_dbg(&spi->dev, "setup --> %d\n", status);
|
||||
}
|
||||
|
||||
return 0;
|
||||
|
||||
fail:
|
||||
kfree(mcp);
|
||||
return status;
|
||||
}
|
||||
|
||||
static int mcp23s08_remove(struct spi_device *spi)
|
||||
{
|
||||
struct mcp23s08 *mcp = spi_get_drvdata(spi);
|
||||
struct mcp23s08_platform_data *pdata = spi->dev.platform_data;
|
||||
int status = 0;
|
||||
|
||||
if (pdata->teardown) {
|
||||
status = pdata->teardown(spi,
|
||||
mcp->chip.base, mcp->chip.ngpio,
|
||||
pdata->context);
|
||||
if (status < 0) {
|
||||
dev_err(&spi->dev, "%s --> %d\n", "teardown", status);
|
||||
return status;
|
||||
}
|
||||
}
|
||||
|
||||
status = gpiochip_remove(&mcp->chip);
|
||||
if (status == 0)
|
||||
kfree(mcp);
|
||||
else
|
||||
dev_err(&spi->dev, "%s --> %d\n", "remove", status);
|
||||
return status;
|
||||
}
|
||||
|
||||
static struct spi_driver mcp23s08_driver = {
|
||||
.probe = mcp23s08_probe,
|
||||
.remove = mcp23s08_remove,
|
||||
.driver = {
|
||||
.name = "mcp23s08",
|
||||
.owner = THIS_MODULE,
|
||||
},
|
||||
};
|
||||
|
||||
/*----------------------------------------------------------------------*/
|
||||
|
||||
static int __init mcp23s08_init(void)
|
||||
{
|
||||
return spi_register_driver(&mcp23s08_driver);
|
||||
}
|
||||
module_init(mcp23s08_init);
|
||||
|
||||
static void __exit mcp23s08_exit(void)
|
||||
{
|
||||
spi_unregister_driver(&mcp23s08_driver);
|
||||
}
|
||||
module_exit(mcp23s08_exit);
|
||||
|
||||
MODULE_LICENSE("GPL");
|
||||
|
||||
|
|
@ -0,0 +1,24 @@
|
|||
|
||||
/* FIXME driver should be able to handle all four slaves that
|
||||
* can be hooked up to each chipselect, as well as IRQs...
|
||||
*/
|
||||
|
||||
struct mcp23s08_platform_data {
|
||||
/* four slaves can share one SPI chipselect */
|
||||
u8 slave;
|
||||
|
||||
/* number assigned to the first GPIO */
|
||||
unsigned base;
|
||||
|
||||
/* pins with pullups */
|
||||
u8 pullups;
|
||||
|
||||
void *context; /* param to setup/teardown */
|
||||
|
||||
int (*setup)(struct spi_device *spi,
|
||||
int gpio, unsigned ngpio,
|
||||
void *context);
|
||||
int (*teardown)(struct spi_device *spi,
|
||||
int gpio, unsigned ngpio,
|
||||
void *context);
|
||||
};
|
||||
Reference in New Issue