gpio: adp5588-gpio: support interrupt controller

Implement irq_chip functionality on ADP5588/5587 GPIO expanders.  Only
level sensitive interrupts are supported.  Interrupts provided by this
irq_chip must be requested using request_threaded_irq().

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 263 insertions, 21 deletions

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index bc7b0fca6415..3f3181dac8d7 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -272,6 +272,13 @@ config GPIO_ADP5588
           To compile this driver as a module, choose M here: the module will be
           called adp5588-gpio.
 
+config GPIO_ADP5588_IRQ
+        bool "Interrupt controller support for ADP5588"
+        depends on GPIO_ADP5588=y
+        help
+          Say yes here to enable the adp5588 to be used as an interrupt
+          controller. It requires the driver to be built in the kernel.
+
 comment "PCI GPIO expanders:"
 
 config GPIO_CS5535
diff --git a/drivers/gpio/adp5588-gpio.c b/drivers/gpio/adp5588-gpio.c
index 2e8e9e24f887..0871f78af593 100644
--- a/drivers/gpio/adp5588-gpio.c
+++ b/drivers/gpio/adp5588-gpio.c
@@ -1,8 +1,8 @@
 /*
  * GPIO Chip driver for Analog Devices
- * ADP5588 I/O Expander and QWERTY Keypad Controller
+ * ADP5588/ADP5587 I/O Expander and QWERTY Keypad Controller
  *
- * Copyright 2009 Analog Devices Inc.
+ * Copyright 2009-2010 Analog Devices Inc.
  *
  * Licensed under the GPL-2 or later.
  */
@@ -13,21 +13,34 @@
 #include <linux/init.h>
 #include <linux/i2c.h>
 #include <linux/gpio.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
 
 #include <linux/i2c/adp5588.h>
 
-#define DRV_NAME                "adp5588-gpio"
-#define MAXGPIO                 18
-#define ADP_BANK(offs)          ((offs) >> 3)
-#define ADP_BIT(offs)           (1u << ((offs) & 0x7))
+#define DRV_NAME        "adp5588-gpio"
+
+/*
+ * Early pre 4.0 Silicon required to delay readout by at least 25ms,
+ * since the Event Counter Register updated 25ms after the interrupt
+ * asserted.
+ */
+#define WA_DELAYED_READOUT_REVID(rev)   ((rev) < 4)
 
 struct adp5588_gpio {
         struct i2c_client *client;
         struct gpio_chip gpio_chip;
         struct mutex lock;      /* protect cached dir, dat_out */
+        /* protect serialized access to the interrupt controller bus */
+        struct mutex irq_lock;
         unsigned gpio_start;
+        unsigned irq_base;
         uint8_t dat_out[3];
         uint8_t dir[3];
+        uint8_t int_lvl[3];
+        uint8_t int_en[3];
+        uint8_t irq_mask[3];
+        uint8_t irq_stat[3];
 };
 
 static int adp5588_gpio_read(struct i2c_client *client, u8 reg)
@@ -55,8 +68,8 @@ static int adp5588_gpio_get_value(struct gpio_chip *chip, unsigned off)
         struct adp5588_gpio *dev =
             container_of(chip, struct adp5588_gpio, gpio_chip);
 
-        return !!(adp5588_gpio_read(dev->client, GPIO_DAT_STAT1 + ADP_BANK(off))
-                  & ADP_BIT(off));
+        return !!(adp5588_gpio_read(dev->client,
+                  GPIO_DAT_STAT1 + ADP5588_BANK(off)) & ADP5588_BIT(off));
 }
 
 static void adp5588_gpio_set_value(struct gpio_chip *chip,
@@ -66,8 +79,8 @@ static void adp5588_gpio_set_value(struct gpio_chip *chip,
         struct adp5588_gpio *dev =
             container_of(chip, struct adp5588_gpio, gpio_chip);
 
-        bank = ADP_BANK(off);
-        bit = ADP_BIT(off);
+        bank = ADP5588_BANK(off);
+        bit = ADP5588_BIT(off);
 
         mutex_lock(&dev->lock);
         if (val)
@@ -87,10 +100,10 @@ static int adp5588_gpio_direction_input(struct gpio_chip *chip, unsigned off)
         struct adp5588_gpio *dev =
             container_of(chip, struct adp5588_gpio, gpio_chip);
 
-        bank = ADP_BANK(off);
+        bank = ADP5588_BANK(off);
 
         mutex_lock(&dev->lock);
-        dev->dir[bank] &= ~ADP_BIT(off);
+        dev->dir[bank] &= ~ADP5588_BIT(off);
         ret = adp5588_gpio_write(dev->client, GPIO_DIR1 + bank, dev->dir[bank]);
         mutex_unlock(&dev->lock);
 
@@ -105,8 +118,8 @@ static int adp5588_gpio_direction_output(struct gpio_chip *chip,
         struct adp5588_gpio *dev =
             container_of(chip, struct adp5588_gpio, gpio_chip);
 
-        bank = ADP_BANK(off);
-        bit = ADP_BIT(off);
+        bank = ADP5588_BANK(off);
+        bit = ADP5588_BIT(off);
 
         mutex_lock(&dev->lock);
         dev->dir[bank] |= bit;
@@ -125,6 +138,213 @@ static int adp5588_gpio_direction_output(struct gpio_chip *chip,
         return ret;
 }
 
+#ifdef CONFIG_GPIO_ADP5588_IRQ
+static int adp5588_gpio_to_irq(struct gpio_chip *chip, unsigned off)
+{
+        struct adp5588_gpio *dev =
+                container_of(chip, struct adp5588_gpio, gpio_chip);
+        return dev->irq_base + off;
+}
+
+static void adp5588_irq_bus_lock(unsigned int irq)
+{
+        struct adp5588_gpio *dev = get_irq_chip_data(irq);
+        mutex_lock(&dev->irq_lock);
+}
+
+ /*
+  * genirq core code can issue chip->mask/unmask from atomic context.
+  * This doesn't work for slow busses where an access needs to sleep.
+  * bus_sync_unlock() is therefore called outside the atomic context,
+  * syncs the current irq mask state with the slow external controller
+  * and unlocks the bus.
+  */
+
+static void adp5588_irq_bus_sync_unlock(unsigned int irq)
+{
+        struct adp5588_gpio *dev = get_irq_chip_data(irq);
+        int i;
+
+        for (i = 0; i <= ADP5588_BANK(ADP5588_MAXGPIO); i++)
+                if (dev->int_en[i] ^ dev->irq_mask[i]) {
+                        dev->int_en[i] = dev->irq_mask[i];
+                        adp5588_gpio_write(dev->client, GPIO_INT_EN1 + i,
+                                           dev->int_en[i]);
+                }
+
+        mutex_unlock(&dev->irq_lock);
+}
+
+static void adp5588_irq_mask(unsigned int irq)
+{
+        struct adp5588_gpio *dev = get_irq_chip_data(irq);
+        unsigned gpio = irq - dev->irq_base;
+
+        dev->irq_mask[ADP5588_BANK(gpio)] &= ~ADP5588_BIT(gpio);
+}
+
+static void adp5588_irq_unmask(unsigned int irq)
+{
+        struct adp5588_gpio *dev = get_irq_chip_data(irq);
+        unsigned gpio = irq - dev->irq_base;
+
+        dev->irq_mask[ADP5588_BANK(gpio)] |= ADP5588_BIT(gpio);
+}
+
+static int adp5588_irq_set_type(unsigned int irq, unsigned int type)
+{
+        struct adp5588_gpio *dev = get_irq_chip_data(irq);
+        uint16_t gpio = irq - dev->irq_base;
+        unsigned bank, bit;
+
+        if ((type & IRQ_TYPE_EDGE_BOTH)) {
+                dev_err(&dev->client->dev, "irq %d: unsupported type %d\n",
+                        irq, type);
+                return -EINVAL;
+        }
+
+        bank = ADP5588_BANK(gpio);
+        bit = ADP5588_BIT(gpio);
+
+        if (type & IRQ_TYPE_LEVEL_HIGH)
+                dev->int_lvl[bank] |= bit;
+        else if (type & IRQ_TYPE_LEVEL_LOW)
+                dev->int_lvl[bank] &= ~bit;
+        else
+                return -EINVAL;
+
+        adp5588_gpio_direction_input(&dev->gpio_chip, gpio);
+        adp5588_gpio_write(dev->client, GPIO_INT_LVL1 + bank,
+                           dev->int_lvl[bank]);
+
+        return 0;
+}
+
+static struct irq_chip adp5588_irq_chip = {
+        .name                   = "adp5588",
+        .mask                   = adp5588_irq_mask,
+        .unmask                 = adp5588_irq_unmask,
+        .bus_lock               = adp5588_irq_bus_lock,
+        .bus_sync_unlock        = adp5588_irq_bus_sync_unlock,
+        .set_type               = adp5588_irq_set_type,
+};
+
+static int adp5588_gpio_read_intstat(struct i2c_client *client, u8 *buf)
+{
+        int ret = i2c_smbus_read_i2c_block_data(client, GPIO_INT_STAT1, 3, buf);
+
+        if (ret < 0)
+                dev_err(&client->dev, "Read INT_STAT Error\n");
+
+        return ret;
+}
+
+static irqreturn_t adp5588_irq_handler(int irq, void *devid)
+{
+        struct adp5588_gpio *dev = devid;
+        unsigned status, bank, bit, pending;
+        int ret;
+        status = adp5588_gpio_read(dev->client, INT_STAT);
+
+        if (status & ADP5588_GPI_INT) {
+                ret = adp5588_gpio_read_intstat(dev->client, dev->irq_stat);
+                if (ret < 0)
+                        memset(dev->irq_stat, 0, ARRAY_SIZE(dev->irq_stat));
+
+                for (bank = 0; bank <= ADP5588_BANK(ADP5588_MAXGPIO);
+                        bank++, bit = 0) {
+                        pending = dev->irq_stat[bank] & dev->irq_mask[bank];
+
+                        while (pending) {
+                                if (pending & (1 << bit)) {
+                                        handle_nested_irq(dev->irq_base +
+                                                          (bank << 3) + bit);
+                                        pending &= ~(1 << bit);
+
+                                }
+                                bit++;
+                        }
+                }
+        }
+
+        adp5588_gpio_write(dev->client, INT_STAT, status); /* Status is W1C */
+
+        return IRQ_HANDLED;
+}
+
+static int adp5588_irq_setup(struct adp5588_gpio *dev)
+{
+        struct i2c_client *client = dev->client;
+        struct adp5588_gpio_platform_data *pdata = client->dev.platform_data;
+        unsigned gpio;
+        int ret;
+
+        adp5588_gpio_write(client, CFG, ADP5588_AUTO_INC);
+        adp5588_gpio_write(client, INT_STAT, -1); /* status is W1C */
+        adp5588_gpio_read_intstat(client, dev->irq_stat); /* read to clear */
+
+        dev->irq_base = pdata->irq_base;
+        mutex_init(&dev->irq_lock);
+
+        for (gpio = 0; gpio < dev->gpio_chip.ngpio; gpio++) {
+                int irq = gpio + dev->irq_base;
+                set_irq_chip_data(irq, dev);
+                set_irq_chip_and_handler(irq, &adp5588_irq_chip,
+                                         handle_level_irq);
+                set_irq_nested_thread(irq, 1);
+#ifdef CONFIG_ARM
+                /*
+                 * ARM needs us to explicitly flag the IRQ as VALID,
+                 * once we do so, it will also set the noprobe.
+                 */
+                set_irq_flags(irq, IRQF_VALID);
+#else
+                set_irq_noprobe(irq);
+#endif
+        }
+
+        ret = request_threaded_irq(client->irq,
+                                   NULL,
+                                   adp5588_irq_handler,
+                                   IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
+                                   dev_name(&client->dev), dev);
+        if (ret) {
+                dev_err(&client->dev, "failed to request irq %d\n",
+                        client->irq);
+                goto out;
+        }
+
+        dev->gpio_chip.to_irq = adp5588_gpio_to_irq;
+        adp5588_gpio_write(client, CFG,
+                ADP5588_AUTO_INC | ADP5588_INT_CFG | ADP5588_GPI_INT);
+
+        return 0;
+
+out:
+        dev->irq_base = 0;
+        return ret;
+}
+
+static void adp5588_irq_teardown(struct adp5588_gpio *dev)
+{
+        if (dev->irq_base)
+                free_irq(dev->client->irq, dev);
+}
+
+#else
+static int adp5588_irq_setup(struct adp5588_gpio *dev)
+{
+        struct i2c_client *client = dev->client;
+        dev_warn(&client->dev, "interrupt support not compiled in\n");
+
+        return 0;
+}
+
+static void adp5588_irq_teardown(struct adp5588_gpio *dev)
+{
+}
+#endif /* CONFIG_GPIO_ADP5588_IRQ */
+
 static int __devinit adp5588_gpio_probe(struct i2c_client *client,
                                         const struct i2c_device_id *id)
 {
@@ -160,37 +380,46 @@ static int __devinit adp5588_gpio_probe(struct i2c_client *client,
         gc->can_sleep = 1;
 
         gc->base = pdata->gpio_start;
-        gc->ngpio = MAXGPIO;
+        gc->ngpio = ADP5588_MAXGPIO;
         gc->label = client->name;
         gc->owner = THIS_MODULE;
 
         mutex_init(&dev->lock);
 
-
         ret = adp5588_gpio_read(dev->client, DEV_ID);
         if (ret < 0)
                 goto err;
 
         revid = ret & ADP5588_DEVICE_ID_MASK;
 
-        for (i = 0, ret = 0; i <= ADP_BANK(MAXGPIO); i++) {
+        for (i = 0, ret = 0; i <= ADP5588_BANK(ADP5588_MAXGPIO); i++) {
                 dev->dat_out[i] = adp5588_gpio_read(client, GPIO_DAT_OUT1 + i);
                 dev->dir[i] = adp5588_gpio_read(client, GPIO_DIR1 + i);
                 ret |= adp5588_gpio_write(client, KP_GPIO1 + i, 0);
                 ret |= adp5588_gpio_write(client, GPIO_PULL1 + i,
                                 (pdata->pullup_dis_mask >> (8 * i)) & 0xFF);
-
+                ret |= adp5588_gpio_write(client, GPIO_INT_EN1 + i, 0);
                 if (ret)
                         goto err;
         }
 
+        if (pdata->irq_base) {
+                if (WA_DELAYED_READOUT_REVID(revid)) {
+                        dev_warn(&client->dev, "GPIO int not supported\n");
+                } else {
+                        ret = adp5588_irq_setup(dev);
+                        if (ret)
+                                goto err;
+                }
+        }
+
         ret = gpiochip_add(&dev->gpio_chip);
         if (ret)
-                goto err;
+                goto err_irq;
 
-        dev_info(&client->dev, "gpios %d..%d on a %s Rev. %d\n",
+        dev_info(&client->dev, "gpios %d..%d (IRQ Base %d) on a %s Rev. %d\n",
                         gc->base, gc->base + gc->ngpio - 1,
-                        client->name, revid);
+                        pdata->irq_base, client->name, revid);
 
         if (pdata->setup) {
                 ret = pdata->setup(client, gc->base, gc->ngpio, pdata->context);
@@ -199,8 +428,11 @@ static int __devinit adp5588_gpio_probe(struct i2c_client *client,
         }
 
         i2c_set_clientdata(client, dev);
+
         return 0;
 
+err_irq:
+        adp5588_irq_teardown(dev);
 err:
         kfree(dev);
         return ret;
@@ -222,6 +454,9 @@ static int __devexit adp5588_gpio_remove(struct i2c_client *client)
                 }
         }
 
+        if (dev->irq_base)
+                free_irq(dev->client->irq, dev);
+
         ret = gpiochip_remove(&dev->gpio_chip);
         if (ret) {
                 dev_err(&client->dev, "gpiochip_remove failed %d\n", ret);