diff options
Diffstat (limited to 'drivers/gpio')
| -rw-r--r-- | drivers/gpio/Kconfig | 7 | ||||
| -rw-r--r-- | drivers/gpio/Makefile | 1 | ||||
| -rw-r--r-- | drivers/gpio/mcp23s08.c | 357 |
3 files changed, 365 insertions, 0 deletions
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig index 36d5d6aefc0..d924a32c089 100644 --- a/drivers/gpio/Kconfig +++ b/drivers/gpio/Kconfig @@ -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 diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile index b469ab24fb1..a1fd877ac52 100644 --- a/drivers/gpio/Makefile +++ b/drivers/gpio/Makefile @@ -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 diff --git a/drivers/gpio/mcp23s08.c b/drivers/gpio/mcp23s08.c new file mode 100644 index 00000000000..bb60e8c1a1f --- /dev/null +++ b/drivers/gpio/mcp23s08.c @@ -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"); + |