/* * 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; mcp->chip.owner = THIS_MODULE; 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");