diff options
author | Lars Poeschel <poeschel@lemonage.de> | 2014-01-16 10:44:15 (GMT) |
---|---|---|
committer | Linus Walleij <linus.walleij@linaro.org> | 2014-01-17 14:30:14 (GMT) |
commit | 4e47f91bf741e011a90ceb6241b8d78141709733 (patch) | |
tree | 1febf3cbbf59a1202dc5d944d392ce28b6b851fe /drivers/gpio/gpio-mcp23s08.c | |
parent | 785acec3eecf4c21bab9e24afb5d354b57a72e03 (diff) | |
download | linux-4e47f91bf741e011a90ceb6241b8d78141709733.tar.xz |
gpio: mcp23s08: Add irq functionality for i2c chips
This adds interrupt functionality for i2c chips to the driver.
They can act as a interrupt-controller and generate interrupts, if
the inputs change.
This is tested with a mcp23017 chip on an arm based platform.
v3:
- be a bit more clear that the irq functionality is also available
on spi versions of the chips, but the linux driver does not support
this yet
v2:
- some more word about irq-mirror property in binding doc
- use of_read_bool instead of of_find_property for
"interrupt-contrller" and "irq-mirror"
- cache the "interrupt-controller" for remove function
- do set the irq-mirror bit only if device is marked as
interrupt-controller
- do create the irq mapping and setup of irq_desc of all possible
interrupts in probe path instead of in gpio_to_irq
- mark gpios as in use as interrupts in irq in irq_startup and
unlock it in irq_shutdown
- rename virq to child_irq
- remove dev argument from mcp23s08_irq_setup function
- move gpiochip_add before mcp23s08_irq_setup in probe path
Signed-off-by: Lars Poeschel <poeschel@lemonage.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Diffstat (limited to 'drivers/gpio/gpio-mcp23s08.c')
-rw-r--r-- | drivers/gpio/gpio-mcp23s08.c | 248 |
1 files changed, 243 insertions, 5 deletions
diff --git a/drivers/gpio/gpio-mcp23s08.c b/drivers/gpio/gpio-mcp23s08.c index b16401e..ef3fd48 100644 --- a/drivers/gpio/gpio-mcp23s08.c +++ b/drivers/gpio/gpio-mcp23s08.c @@ -1,5 +1,13 @@ /* - * MCP23S08 SPI/GPIO gpio expander driver + * MCP23S08 SPI/I2C GPIO gpio expander driver + * + * The inputs and outputs of the mcp23s08, mcp23s17, mcp23008 and mcp23017 are + * supported. + * For the I2C versions of the chips (mcp23008 and mcp23017) generation of + * interrupts is also supported. + * The hardware of the SPI versions of the chips (mcp23s08 and mcp23s17) is + * also capable of generating interrupts, but the linux driver does not + * support that yet. */ #include <linux/kernel.h> @@ -12,7 +20,8 @@ #include <linux/spi/mcp23s08.h> #include <linux/slab.h> #include <asm/byteorder.h> -#include <linux/of.h> +#include <linux/interrupt.h> +#include <linux/of_irq.h> #include <linux/of_device.h> /** @@ -34,6 +43,7 @@ #define MCP_DEFVAL 0x03 #define MCP_INTCON 0x04 #define MCP_IOCON 0x05 +# define IOCON_MIRROR (1 << 6) # define IOCON_SEQOP (1 << 5) # define IOCON_HAEN (1 << 3) # define IOCON_ODR (1 << 2) @@ -57,8 +67,14 @@ struct mcp23s08 { u8 addr; u16 cache[11]; + u16 irq_rise; + u16 irq_fall; + int irq; + bool irq_controller; /* lock protects the cached values */ struct mutex lock; + struct mutex irq_lock; + struct irq_domain *irq_domain; struct gpio_chip chip; @@ -77,6 +93,11 @@ struct mcp23s08_driver_data { struct mcp23s08 chip[]; }; +/* This lock class tells lockdep that GPIO irqs are in a different + * category than their parents, so it won't report false recursion. + */ +static struct lock_class_key gpio_lock_class; + /*----------------------------------------------------------------------*/ #if IS_ENABLED(CONFIG_I2C) @@ -316,6 +337,195 @@ mcp23s08_direction_output(struct gpio_chip *chip, unsigned offset, int value) } /*----------------------------------------------------------------------*/ +static irqreturn_t mcp23s08_irq(int irq, void *data) +{ + struct mcp23s08 *mcp = data; + int intcap, intf, i; + unsigned int child_irq; + + mutex_lock(&mcp->lock); + intf = mcp->ops->read(mcp, MCP_INTF); + if (intf < 0) { + mutex_unlock(&mcp->lock); + return IRQ_HANDLED; + } + + mcp->cache[MCP_INTF] = intf; + + intcap = mcp->ops->read(mcp, MCP_INTCAP); + if (intcap < 0) { + mutex_unlock(&mcp->lock); + return IRQ_HANDLED; + } + + mcp->cache[MCP_INTCAP] = intcap; + mutex_unlock(&mcp->lock); + + + for (i = 0; i < mcp->chip.ngpio; i++) { + if ((BIT(i) & mcp->cache[MCP_INTF]) && + ((BIT(i) & intcap & mcp->irq_rise) || + (mcp->irq_fall & ~intcap & BIT(i)))) { + child_irq = irq_find_mapping(mcp->irq_domain, i); + handle_nested_irq(child_irq); + } + } + + return IRQ_HANDLED; +} + +static int mcp23s08_gpio_to_irq(struct gpio_chip *chip, unsigned offset) +{ + struct mcp23s08 *mcp = container_of(chip, struct mcp23s08, chip); + + return irq_find_mapping(mcp->irq_domain, offset); +} + +static void mcp23s08_irq_mask(struct irq_data *data) +{ + struct mcp23s08 *mcp = irq_data_get_irq_chip_data(data); + unsigned int pos = data->hwirq; + + mcp->cache[MCP_GPINTEN] &= ~BIT(pos); +} + +static void mcp23s08_irq_unmask(struct irq_data *data) +{ + struct mcp23s08 *mcp = irq_data_get_irq_chip_data(data); + unsigned int pos = data->hwirq; + + mcp->cache[MCP_GPINTEN] |= BIT(pos); +} + +static int mcp23s08_irq_set_type(struct irq_data *data, unsigned int type) +{ + struct mcp23s08 *mcp = irq_data_get_irq_chip_data(data); + unsigned int pos = data->hwirq; + int status = 0; + + if ((type & IRQ_TYPE_EDGE_BOTH) == IRQ_TYPE_EDGE_BOTH) { + mcp->cache[MCP_INTCON] &= ~BIT(pos); + mcp->irq_rise |= BIT(pos); + mcp->irq_fall |= BIT(pos); + } else if (type & IRQ_TYPE_EDGE_RISING) { + mcp->cache[MCP_INTCON] &= ~BIT(pos); + mcp->irq_rise |= BIT(pos); + mcp->irq_fall &= ~BIT(pos); + } else if (type & IRQ_TYPE_EDGE_FALLING) { + mcp->cache[MCP_INTCON] &= ~BIT(pos); + mcp->irq_rise &= ~BIT(pos); + mcp->irq_fall |= BIT(pos); + } else + return -EINVAL; + + return status; +} + +static void mcp23s08_irq_bus_lock(struct irq_data *data) +{ + struct mcp23s08 *mcp = irq_data_get_irq_chip_data(data); + + mutex_lock(&mcp->irq_lock); +} + +static void mcp23s08_irq_bus_unlock(struct irq_data *data) +{ + struct mcp23s08 *mcp = irq_data_get_irq_chip_data(data); + + mutex_lock(&mcp->lock); + mcp->ops->write(mcp, MCP_GPINTEN, mcp->cache[MCP_GPINTEN]); + mcp->ops->write(mcp, MCP_DEFVAL, mcp->cache[MCP_DEFVAL]); + mcp->ops->write(mcp, MCP_INTCON, mcp->cache[MCP_INTCON]); + mutex_unlock(&mcp->lock); + mutex_unlock(&mcp->irq_lock); +} + +static unsigned int mcp23s08_irq_startup(struct irq_data *data) +{ + struct mcp23s08 *mcp = irq_data_get_irq_chip_data(data); + + if (gpio_lock_as_irq(&mcp->chip, data->hwirq)) + dev_err(mcp->chip.dev, + "unable to lock HW IRQ %lu for IRQ usage\n", + data->hwirq); + + mcp23s08_irq_unmask(data); + return 0; +} + +static void mcp23s08_irq_shutdown(struct irq_data *data) +{ + struct mcp23s08 *mcp = irq_data_get_irq_chip_data(data); + + mcp23s08_irq_mask(data); + gpio_unlock_as_irq(&mcp->chip, data->hwirq); +} + +static struct irq_chip mcp23s08_irq_chip = { + .name = "gpio-mcp23xxx", + .irq_mask = mcp23s08_irq_mask, + .irq_unmask = mcp23s08_irq_unmask, + .irq_set_type = mcp23s08_irq_set_type, + .irq_bus_lock = mcp23s08_irq_bus_lock, + .irq_bus_sync_unlock = mcp23s08_irq_bus_unlock, + .irq_startup = mcp23s08_irq_startup, + .irq_shutdown = mcp23s08_irq_shutdown, +}; + +static int mcp23s08_irq_setup(struct mcp23s08 *mcp) +{ + struct gpio_chip *chip = &mcp->chip; + int err, irq, j; + + mutex_init(&mcp->irq_lock); + + mcp->irq_domain = irq_domain_add_linear(chip->of_node, chip->ngpio, + &irq_domain_simple_ops, mcp); + if (!mcp->irq_domain) + return -ENODEV; + + err = devm_request_threaded_irq(chip->dev, mcp->irq, NULL, mcp23s08_irq, + IRQF_TRIGGER_LOW | IRQF_ONESHOT, + dev_name(chip->dev), mcp); + if (err != 0) { + dev_err(chip->dev, "unable to request IRQ#%d: %d\n", + mcp->irq, err); + return err; + } + + chip->to_irq = mcp23s08_gpio_to_irq; + + for (j = 0; j < mcp->chip.ngpio; j++) { + irq = irq_create_mapping(mcp->irq_domain, j); + irq_set_lockdep_class(irq, &gpio_lock_class); + irq_set_chip_data(irq, mcp); + irq_set_chip(irq, &mcp23s08_irq_chip); + irq_set_nested_thread(irq, true); +#ifdef CONFIG_ARM + set_irq_flags(irq, IRQF_VALID); +#else + irq_set_noprobe(irq); +#endif + } + return 0; +} + +static void mcp23s08_irq_teardown(struct mcp23s08 *mcp) +{ + unsigned int irq, i; + + free_irq(mcp->irq, mcp); + + for (i = 0; i < mcp->chip.ngpio; i++) { + irq = irq_find_mapping(mcp->irq_domain, i); + if (irq > 0) + irq_dispose_mapping(irq); + } + + irq_domain_remove(mcp->irq_domain); +} + +/*----------------------------------------------------------------------*/ #ifdef CONFIG_DEBUG_FS @@ -370,10 +580,11 @@ done: /*----------------------------------------------------------------------*/ static int mcp23s08_probe_one(struct mcp23s08 *mcp, struct device *dev, - void *data, unsigned addr, - unsigned type, unsigned base, unsigned pullups) + void *data, unsigned addr, unsigned type, + unsigned base, unsigned pullups) { int status; + bool mirror = false; mutex_init(&mcp->lock); @@ -432,13 +643,25 @@ static int mcp23s08_probe_one(struct mcp23s08 *mcp, struct device *dev, /* 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)) { + + mcp->irq_controller = of_property_read_bool(mcp->chip.of_node, + "interrupt-controller"); + if (mcp->irq && mcp->irq_controller && (type == MCP_TYPE_017)) + mirror = of_property_read_bool(mcp->chip.of_node, + "microchip,irq-mirror"); + + if ((status & IOCON_SEQOP) || !(status & IOCON_HAEN) || mirror) { /* mcp23s17 has IOCON twice, make sure they are in sync */ status &= ~(IOCON_SEQOP | (IOCON_SEQOP << 8)); status |= IOCON_HAEN | (IOCON_HAEN << 8); + status &= ~(IOCON_INTPOL | (IOCON_INTPOL << 8)); + if (mirror) + status |= IOCON_MIRROR | (IOCON_MIRROR << 8); + status = mcp->ops->write(mcp, MCP_IOCON, status); if (status < 0) goto fail; @@ -470,6 +693,16 @@ static int mcp23s08_probe_one(struct mcp23s08 *mcp, struct device *dev, } status = gpiochip_add(&mcp->chip); + if (status < 0) + goto fail; + + if (mcp->irq && mcp->irq_controller) { + status = mcp23s08_irq_setup(mcp); + if (status) { + mcp23s08_irq_teardown(mcp); + goto fail; + } + } fail: if (status < 0) dev_dbg(dev, "can't setup chip %d, --> %d\n", @@ -546,6 +779,7 @@ static int mcp230xx_probe(struct i2c_client *client, if (match || !pdata) { base = -1; pullups = 0; + client->irq = irq_of_parse_and_map(client->dev.of_node, 0); } else { if (!gpio_is_valid(pdata->base)) { dev_dbg(&client->dev, "invalid platform data\n"); @@ -559,6 +793,7 @@ static int mcp230xx_probe(struct i2c_client *client, if (!mcp) return -ENOMEM; + mcp->irq = client->irq; status = mcp23s08_probe_one(mcp, &client->dev, client, client->addr, id->driver_data, base, pullups); if (status) @@ -579,6 +814,9 @@ static int mcp230xx_remove(struct i2c_client *client) struct mcp23s08 *mcp = i2c_get_clientdata(client); int status; + if (client->irq && mcp->irq_controller) + mcp23s08_irq_teardown(mcp); + status = gpiochip_remove(&mcp->chip); if (status == 0) kfree(mcp); |