mfd: Add HTCPLD driver

This change introduces a driver for the HTC PLD chip found
on some smartphones, such as the HTC Wizard and HTC Herald.
It works through the I2C bus and acts as a GPIO extender.
Specifically:

 * it can have several sub-devices, each with its own I2C
   address
 * Each sub-device provides 8 output and 8 input pins
 * The chip attaches to one GPIO to signal when any of the
   input GPIOs change -- at which point all chips must be
   scanned for changes

This driver implements the GPIOs throught the kernel's
GPIO and IRQ framework.  This allows any GPIO-servicing
drivers to operate on htcpld pins, such as the gpio-keys
and gpio-leds drivers.

Signed-off-by: Cory Maccarrone <darkstar6262@gmail.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

3 files changed, 720 insertions, 0 deletions

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index d63ab2eec661..9bcd447e71e2 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -78,6 +78,15 @@ config HTC_PASIC3
           HTC Magician devices, respectively. Actual functionality is
           handled by the leds-pasic3 and ds1wm drivers.
 
+config HTC_I2CPLD
+        bool "HTC I2C PLD chip support"
+        depends on I2C=y
+        help
+          If you say yes here you get support for the supposed CPLD
+          found on omap850 HTC devices like the HTC Wizard and HTC Herald.
+          This device provides input and output GPIOs through an I2C
+          interface to one or more sub-chips.
+
 config UCB1400_CORE
         tristate "Philips UCB1400 Core driver"
         depends on AC97_BUS
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index 261635700243..142d31202b14 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -10,6 +10,7 @@ obj-$(CONFIG_MFD_SH_MOBILE_SDHI)		+= sh_mobile_sdhi.o
 
 obj-$(CONFIG_HTC_EGPIO)         += htc-egpio.o
 obj-$(CONFIG_HTC_PASIC3)        += htc-pasic3.o
+obj-$(CONFIG_HTC_I2CPLD)        += htc-i2cpld.o
 
 obj-$(CONFIG_MFD_DM355EVM_MSP)  += dm355evm_msp.o
 
diff --git a/drivers/mfd/htc-i2cpld.c b/drivers/mfd/htc-i2cpld.c
new file mode 100644
index 000000000000..37b9fdab4f36
--- /dev/null
+++ b/drivers/mfd/htc-i2cpld.c
@@ -0,0 +1,710 @@
+/*
+ *  htc-i2cpld.c
+ *  Chip driver for an unknown CPLD chip found on omap850 HTC devices like
+ *  the HTC Wizard and HTC Herald.
+ *  The cpld is located on the i2c bus and acts as an input/output GPIO
+ *  extender.
+ *
+ *  Copyright (C) 2009 Cory Maccarrone <darkstar6262@gmail.com>
+ *
+ *  Based on work done in the linwizard project
+ *  Copyright (C) 2008-2009 Angelo Arrifano <miknix@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <linux/i2c.h>
+#include <linux/irq.h>
+#include <linux/spinlock.h>
+#include <linux/htcpld.h>
+#include <linux/gpio.h>
+
+struct htcpld_chip {
+        spinlock_t              lock;
+
+        /* chip info */
+        u8                      reset;
+        u8                      addr;
+        struct device           *dev;
+        struct i2c_client       *client;
+
+        /* Output details */
+        u8                      cache_out;
+        struct gpio_chip        chip_out;
+
+        /* Input details */
+        u8                      cache_in;
+        struct gpio_chip        chip_in;
+
+        u16                     irqs_enabled;
+        uint                    irq_start;
+        int                     nirqs;
+
+        /*
+         * Work structure to allow for setting values outside of any
+         * possible interrupt context
+         */
+        struct work_struct set_val_work;
+};
+
+struct htcpld_data {
+        /* irq info */
+        u16                irqs_enabled;
+        uint               irq_start;
+        int                nirqs;
+        uint               chained_irq;
+        unsigned int       int_reset_gpio_hi;
+        unsigned int       int_reset_gpio_lo;
+
+        /* htcpld info */
+        struct htcpld_chip *chip;
+        unsigned int       nchips;
+};
+
+/* There does not appear to be a way to proactively mask interrupts
+ * on the htcpld chip itself.  So, we simply ignore interrupts that
+ * aren't desired. */
+static void htcpld_mask(unsigned int irq)
+{
+        struct htcpld_chip *chip = get_irq_chip_data(irq);
+        chip->irqs_enabled &= ~(1 << (irq - chip->irq_start));
+        pr_debug("HTCPLD mask %d %04x\n", irq, chip->irqs_enabled);
+}
+static void htcpld_unmask(unsigned int irq)
+{
+        struct htcpld_chip *chip = get_irq_chip_data(irq);
+        chip->irqs_enabled |= 1 << (irq - chip->irq_start);
+        pr_debug("HTCPLD unmask %d %04x\n", irq, chip->irqs_enabled);
+}
+
+static int htcpld_set_type(unsigned int irq, unsigned int flags)
+{
+        struct irq_desc *d = irq_to_desc(irq);
+
+        if (!d) {
+                pr_err("HTCPLD invalid IRQ: %d\n", irq);
+                return -EINVAL;
+        }
+
+        if (flags & ~IRQ_TYPE_SENSE_MASK)
+                return -EINVAL;
+
+        /* We only allow edge triggering */
+        if (flags & (IRQ_TYPE_LEVEL_LOW|IRQ_TYPE_LEVEL_HIGH))
+                return -EINVAL;
+
+        d->status &= ~IRQ_TYPE_SENSE_MASK;
+        d->status |= flags;
+
+        return 0;
+}
+
+static struct irq_chip htcpld_muxed_chip = {
+        .name     = "htcpld",
+        .mask     = htcpld_mask,
+        .unmask   = htcpld_unmask,
+        .set_type = htcpld_set_type,
+};
+
+/* To properly dispatch IRQ events, we need to read from the
+ * chip.  This is an I2C action that could possibly sleep
+ * (which is bad in interrupt context) -- so we use a threaded
+ * interrupt handler to get around that.
+ */
+static irqreturn_t htcpld_handler(int irq, void *dev)
+{
+        struct htcpld_data *htcpld = dev;
+        unsigned int i;
+        unsigned long flags;
+        int irqpin;
+        struct irq_desc *desc;
+
+        if (!htcpld) {
+                pr_debug("htcpld is null in ISR\n");
+                return IRQ_HANDLED;
+        }
+
+        /*
+         * For each chip, do a read of the chip and trigger any interrupts
+         * desired.  The interrupts will be triggered from LSB to MSB (i.e.
+         * bit 0 first, then bit 1, etc.)
+         *
+         * For chips that have no interrupt range specified, just skip 'em.
+         */
+        for (i = 0; i < htcpld->nchips; i++) {
+                struct htcpld_chip *chip = &htcpld->chip[i];
+                struct i2c_client *client;
+                int val;
+                unsigned long uval, old_val;
+
+                if (!chip) {
+                        pr_debug("chip %d is null in ISR\n", i);
+                        continue;
+                }
+
+                if (chip->nirqs == 0)
+                        continue;
+
+                client = chip->client;
+                if (!client) {
+                        pr_debug("client %d is null in ISR\n", i);
+                        continue;
+                }
+
+                /* Scan the chip */
+                val = i2c_smbus_read_byte_data(client, chip->cache_out);
+                if (val < 0) {
+                        /* Throw a warning and skip this chip */
+                        dev_warn(chip->dev, "Unable to read from chip: %d\n",
+                                 val);
+                        continue;
+                }
+
+                uval = (unsigned long)val;
+
+                spin_lock_irqsave(&chip->lock, flags);
+
+                /* Save away the old value so we can compare it */
+                old_val = chip->cache_in;
+
+                /* Write the new value */
+                chip->cache_in = uval;
+
+                spin_unlock_irqrestore(&chip->lock, flags);
+
+                /*
+                 * For each bit in the data (starting at bit 0), trigger
+                 * associated interrupts.
+                 */
+                for (irqpin = 0; irqpin < chip->nirqs; irqpin++) {
+                        unsigned oldb, newb;
+                        int flags;
+
+                        irq = chip->irq_start + irqpin;
+                        desc = irq_to_desc(irq);
+                        flags = desc->status;
+
+                        /* Run the IRQ handler, but only if the bit value
+                         * changed, and the proper flags are set */
+                        oldb = (old_val >> irqpin) & 1;
+                        newb = (uval >> irqpin) & 1;
+
+                        if ((!oldb && newb && (flags & IRQ_TYPE_EDGE_RISING)) ||
+                            (oldb && !newb &&
+                             (flags & IRQ_TYPE_EDGE_FALLING))) {
+                                pr_debug("fire IRQ %d\n", irqpin);
+                                desc->handle_irq(irq, desc);
+                        }
+                }
+        }
+
+        /*
+         * In order to continue receiving interrupts, the int_reset_gpio must
+         * be asserted.
+         */
+        if (htcpld->int_reset_gpio_hi)
+                gpio_set_value(htcpld->int_reset_gpio_hi, 1);
+        if (htcpld->int_reset_gpio_lo)
+                gpio_set_value(htcpld->int_reset_gpio_lo, 0);
+
+        return IRQ_HANDLED;
+}
+
+/*
+ * The GPIO set routines can be called from interrupt context, especially if,
+ * for example they're attached to the led-gpio framework and a trigger is
+ * enabled.  As such, we declared work above in the htcpld_chip structure,
+ * and that work is scheduled in the set routine.  The kernel can then run
+ * the I2C functions, which will sleep, in process context.
+ */
+void htcpld_chip_set(struct gpio_chip *chip, unsigned offset, int val)
+{
+        struct i2c_client *client;
+        struct htcpld_chip *chip_data;
+        unsigned long flags;
+
+        chip_data = container_of(chip, struct htcpld_chip, chip_out);
+        if (!chip_data)
+                return;
+
+        client = chip_data->client;
+        if (client == NULL)
+                return;
+
+        spin_lock_irqsave(&chip_data->lock, flags);
+        if (val)
+                chip_data->cache_out |= (1 << offset);
+        else
+                chip_data->cache_out &= ~(1 << offset);
+        spin_unlock_irqrestore(&chip_data->lock, flags);
+
+        schedule_work(&(chip_data->set_val_work));
+}
+
+void htcpld_chip_set_ni(struct work_struct *work)
+{
+        struct htcpld_chip *chip_data;
+        struct i2c_client *client;
+
+        chip_data = container_of(work, struct htcpld_chip, set_val_work);
+        client = chip_data->client;
+        i2c_smbus_read_byte_data(client, chip_data->cache_out);
+}
+
+int htcpld_chip_get(struct gpio_chip *chip, unsigned offset)
+{
+        struct htcpld_chip *chip_data;
+        int val = 0;
+        int is_input = 0;
+
+        /* Try out first */
+        chip_data = container_of(chip, struct htcpld_chip, chip_out);
+        if (!chip_data) {
+                /* Try in */
+                is_input = 1;
+                chip_data = container_of(chip, struct htcpld_chip, chip_in);
+                if (!chip_data)
+                        return -EINVAL;
+        }
+
+        /* Determine if this is an input or output GPIO */
+        if (!is_input)
+                /* Use the output cache */
+                val = (chip_data->cache_out >> offset) & 1;
+        else
+                /* Use the input cache */
+                val = (chip_data->cache_in >> offset) & 1;
+
+        if (val)
+                return 1;
+        else
+                return 0;
+}
+
+static int htcpld_direction_output(struct gpio_chip *chip,
+                                        unsigned offset, int value)
+{
+        htcpld_chip_set(chip, offset, value);
+        return 0;
+}
+
+static int htcpld_direction_input(struct gpio_chip *chip,
+                                        unsigned offset)
+{
+        /*
+         * No-op: this function can only be called on the input chip.
+         * We do however make sure the offset is within range.
+         */
+        return (offset < chip->ngpio) ? 0 : -EINVAL;
+}
+
+int htcpld_chip_to_irq(struct gpio_chip *chip, unsigned offset)
+{
+        struct htcpld_chip *chip_data;
+
+        chip_data = container_of(chip, struct htcpld_chip, chip_in);
+
+        if (offset < chip_data->nirqs)
+                return chip_data->irq_start + offset;
+        else
+                return -EINVAL;
+}
+
+void htcpld_chip_reset(struct i2c_client *client)
+{
+        struct htcpld_chip *chip_data = i2c_get_clientdata(client);
+        if (!chip_data)
+                return;
+
+        i2c_smbus_read_byte_data(
+                client, (chip_data->cache_out = chip_data->reset));
+}
+
+static int __devinit htcpld_setup_chip_irq(
+                struct platform_device *pdev,
+                int chip_index)
+{
+        struct htcpld_data *htcpld;
+        struct device *dev = &pdev->dev;
+        struct htcpld_core_platform_data *pdata;
+        struct htcpld_chip *chip;
+        struct htcpld_chip_platform_data *plat_chip_data;
+        unsigned int irq, irq_end;
+        int ret = 0;
+
+        /* Get the platform and driver data */
+        pdata = dev->platform_data;
+        htcpld = platform_get_drvdata(pdev);
+        chip = &htcpld->chip[chip_index];
+        plat_chip_data = &pdata->chip[chip_index];
+
+        /* Setup irq handlers */
+        irq_end = chip->irq_start + chip->nirqs;
+        for (irq = chip->irq_start; irq < irq_end; irq++) {
+                set_irq_chip(irq, &htcpld_muxed_chip);
+                set_irq_chip_data(irq, chip);
+                set_irq_handler(irq, handle_simple_irq);
+#ifdef CONFIG_ARM
+                set_irq_flags(irq, IRQF_VALID | IRQF_PROBE);
+#else
+                set_irq_probe(irq);
+#endif
+        }
+
+        return ret;
+}
+
+static int __devinit htcpld_register_chip_i2c(
+                struct platform_device *pdev,
+                int chip_index)
+{
+        struct htcpld_data *htcpld;
+        struct device *dev = &pdev->dev;
+        struct htcpld_core_platform_data *pdata;
+        struct htcpld_chip *chip;
+        struct htcpld_chip_platform_data *plat_chip_data;
+        struct i2c_adapter *adapter;
+        struct i2c_client *client;
+        struct i2c_board_info info;
+
+        /* Get the platform and driver data */
+        pdata = dev->platform_data;
+        htcpld = platform_get_drvdata(pdev);
+        chip = &htcpld->chip[chip_index];
+        plat_chip_data = &pdata->chip[chip_index];
+
+        adapter = i2c_get_adapter(pdata->i2c_adapter_id);
+        if (adapter == NULL) {
+                /* Eek, no such I2C adapter!  Bail out. */
+                dev_warn(dev, "Chip at i2c address 0x%x: Invalid i2c adapter %d\n",
+                         plat_chip_data->addr, pdata->i2c_adapter_id);
+                return -ENODEV;
+        }
+
+        if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_BYTE_DATA)) {
+                dev_warn(dev, "i2c adapter %d non-functional\n",
+                         pdata->i2c_adapter_id);
+                return -EINVAL;
+        }
+
+        memset(&info, 0, sizeof(struct i2c_board_info));
+        info.addr = plat_chip_data->addr;
+        strlcpy(info.type, "htcpld-chip", I2C_NAME_SIZE);
+        info.platform_data = chip;
+
+        /* Add the I2C device.  This calls the probe() function. */
+        client = i2c_new_device(adapter, &info);
+        if (!client) {
+                /* I2C device registration failed, contineu with the next */
+                dev_warn(dev, "Unable to add I2C device for 0x%x\n",
+                         plat_chip_data->addr);
+                return -ENODEV;
+        }
+
+        i2c_set_clientdata(client, chip);
+        snprintf(client->name, I2C_NAME_SIZE, "Chip_0x%d", client->addr);
+        chip->client = client;
+
+        /* Reset the chip */
+        htcpld_chip_reset(client);
+        chip->cache_in = i2c_smbus_read_byte_data(client, chip->cache_out);
+
+        return 0;
+}
+
+static void __devinit htcpld_unregister_chip_i2c(
+                struct platform_device *pdev,
+                int chip_index)
+{
+        struct htcpld_data *htcpld;
+        struct htcpld_chip *chip;
+
+        /* Get the platform and driver data */
+        htcpld = platform_get_drvdata(pdev);
+        chip = &htcpld->chip[chip_index];
+
+        if (chip->client)
+                i2c_unregister_device(chip->client);
+}
+
+static int __devinit htcpld_register_chip_gpio(
+                struct platform_device *pdev,
+                int chip_index)
+{
+        struct htcpld_data *htcpld;
+        struct device *dev = &pdev->dev;
+        struct htcpld_core_platform_data *pdata;
+        struct htcpld_chip *chip;
+        struct htcpld_chip_platform_data *plat_chip_data;
+        struct gpio_chip *gpio_chip;
+        int ret = 0;
+
+        /* Get the platform and driver data */
+        pdata = dev->platform_data;
+        htcpld = platform_get_drvdata(pdev);
+        chip = &htcpld->chip[chip_index];
+        plat_chip_data = &pdata->chip[chip_index];
+
+        /* Setup the GPIO chips */
+        gpio_chip = &(chip->chip_out);
+        gpio_chip->label           = "htcpld-out";
+        gpio_chip->dev             = dev;
+        gpio_chip->owner           = THIS_MODULE;
+        gpio_chip->get             = htcpld_chip_get;
+        gpio_chip->set             = htcpld_chip_set;
+        gpio_chip->direction_input = NULL;
+        gpio_chip->direction_output = htcpld_direction_output;
+        gpio_chip->base            = plat_chip_data->gpio_out_base;
+        gpio_chip->ngpio           = plat_chip_data->num_gpios;
+
+        gpio_chip = &(chip->chip_in);
+        gpio_chip->label           = "htcpld-in";
+        gpio_chip->dev             = dev;
+        gpio_chip->owner           = THIS_MODULE;
+        gpio_chip->get             = htcpld_chip_get;
+        gpio_chip->set             = NULL;
+        gpio_chip->direction_input = htcpld_direction_input;
+        gpio_chip->direction_output = NULL;
+        gpio_chip->to_irq          = htcpld_chip_to_irq;
+        gpio_chip->base            = plat_chip_data->gpio_in_base;
+        gpio_chip->ngpio           = plat_chip_data->num_gpios;
+
+        /* Add the GPIO chips */
+        ret = gpiochip_add(&(chip->chip_out));
+        if (ret) {
+                dev_warn(dev, "Unable to register output GPIOs for 0x%x: %d\n",
+                         plat_chip_data->addr, ret);
+                return ret;
+        }
+
+        ret = gpiochip_add(&(chip->chip_in));
+        if (ret) {
+                int error;
+
+                dev_warn(dev, "Unable to register input GPIOs for 0x%x: %d\n",
+                         plat_chip_data->addr, ret);
+
+                error = gpiochip_remove(&(chip->chip_out));
+                if (error)
+                        dev_warn(dev, "Error while trying to unregister gpio chip: %d\n", error);
+
+                return ret;
+        }
+
+        return 0;
+}
+
+static int __devinit htcpld_setup_chips(struct platform_device *pdev)
+{
+        struct htcpld_data *htcpld;
+        struct device *dev = &pdev->dev;
+        struct htcpld_core_platform_data *pdata;
+        int i;
+
+        /* Get the platform and driver data */
+        pdata = dev->platform_data;
+        htcpld = platform_get_drvdata(pdev);
+
+        /* Setup each chip's output GPIOs */
+        htcpld->nchips = pdata->num_chip;
+        htcpld->chip = kzalloc(sizeof(struct htcpld_chip) * htcpld->nchips,
+                               GFP_KERNEL);
+        if (!htcpld->chip) {
+                dev_warn(dev, "Unable to allocate memory for chips\n");
+                return -ENOMEM;
+        }
+
+        /* Add the chips as best we can */
+        for (i = 0; i < htcpld->nchips; i++) {
+                int ret;
+
+                /* Setup the HTCPLD chips */
+                htcpld->chip[i].reset = pdata->chip[i].reset;
+                htcpld->chip[i].cache_out = pdata->chip[i].reset;
+                htcpld->chip[i].cache_in = 0;
+                htcpld->chip[i].dev = dev;
+                htcpld->chip[i].irq_start = pdata->chip[i].irq_base;
+                htcpld->chip[i].nirqs = pdata->chip[i].num_irqs;
+
+                INIT_WORK(&(htcpld->chip[i].set_val_work), &htcpld_chip_set_ni);
+                spin_lock_init(&(htcpld->chip[i].lock));
+
+                /* Setup the interrupts for the chip */
+                if (htcpld->chained_irq) {
+                        ret = htcpld_setup_chip_irq(pdev, i);
+                        if (ret)
+                                continue;
+                }
+
+                /* Register the chip with I2C */
+                ret = htcpld_register_chip_i2c(pdev, i);
+                if (ret)
+                        continue;
+
+
+                /* Register the chips with the GPIO subsystem */
+                ret = htcpld_register_chip_gpio(pdev, i);
+                if (ret) {
+                        /* Unregister the chip from i2c and continue */
+                        htcpld_unregister_chip_i2c(pdev, i);
+                        continue;
+                }
+
+                dev_info(dev, "Registered chip at 0x%x\n", pdata->chip[i].addr);
+        }
+
+        return 0;
+}
+
+static int __devinit htcpld_core_probe(struct platform_device *pdev)
+{
+        struct htcpld_data *htcpld;
+        struct device *dev = &pdev->dev;
+        struct htcpld_core_platform_data *pdata;
+        struct resource *res;
+        int ret = 0;
+
+        if (!dev)
+                return -ENODEV;
+
+        pdata = dev->platform_data;
+        if (!pdata) {
+                dev_warn(dev, "Platform data not found for htcpld core!\n");
+                return -ENXIO;
+        }
+
+        htcpld = kzalloc(sizeof(struct htcpld_data), GFP_KERNEL);
+        if (!htcpld)
+                return -ENOMEM;
+
+        /* Find chained irq */
+        ret = -EINVAL;
+        res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+        if (res) {
+                int flags;
+                htcpld->chained_irq = res->start;
+
+                /* Setup the chained interrupt handler */
+                flags = IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING;
+                ret = request_threaded_irq(htcpld->chained_irq,
+                                           NULL, htcpld_handler,
+                                           flags, pdev->name, htcpld);
+                if (ret) {
+                        dev_warn(dev, "Unable to setup chained irq handler: %d\n", ret);
+                        goto fail;
+                } else
+                        device_init_wakeup(dev, 0);
+        }
+
+        /* Set the driver data */
+        platform_set_drvdata(pdev, htcpld);
+
+        /* Setup the htcpld chips */
+        ret = htcpld_setup_chips(pdev);
+        if (ret)
+                goto fail;
+
+        /* Request the GPIO(s) for the int reset and set them up */
+        if (pdata->int_reset_gpio_hi) {
+                ret = gpio_request(pdata->int_reset_gpio_hi, "htcpld-core");
+                if (ret) {
+                        /*
+                         * If it failed, that sucks, but we can probably
+                         * continue on without it.
+                         */
+                        dev_warn(dev, "Unable to request int_reset_gpio_hi -- interrupts may not work\n");
+                        htcpld->int_reset_gpio_hi = 0;
+                } else {
+                        htcpld->int_reset_gpio_hi = pdata->int_reset_gpio_hi;
+                        gpio_set_value(htcpld->int_reset_gpio_hi, 1);
+                }
+        }
+
+        if (pdata->int_reset_gpio_lo) {
+                ret = gpio_request(pdata->int_reset_gpio_lo, "htcpld-core");
+                if (ret) {
+                        /*
+                         * If it failed, that sucks, but we can probably
+                         * continue on without it.
+                         */
+                        dev_warn(dev, "Unable to request int_reset_gpio_lo -- interrupts may not work\n");
+                        htcpld->int_reset_gpio_lo = 0;
+                } else {
+                        htcpld->int_reset_gpio_lo = pdata->int_reset_gpio_lo;
+                        gpio_set_value(htcpld->int_reset_gpio_lo, 0);
+                }
+        }
+
+        dev_info(dev, "Initialized successfully\n");
+        return 0;
+
+fail:
+        kfree(htcpld);
+        return ret;
+}
+
+/* The I2C Driver -- used internally */
+static const struct i2c_device_id htcpld_chip_id[] = {
+        { "htcpld-chip", 0 },
+        { }
+};
+MODULE_DEVICE_TABLE(i2c, htcpld_chip_id);
+
+
+static struct i2c_driver htcpld_chip_driver = {
+        .driver = {
+                .name   = "htcpld-chip",
+        },
+        .id_table = htcpld_chip_id,
+};
+
+/* The Core Driver */
+static struct platform_driver htcpld_core_driver = {
+        .driver = {
+                .name = "i2c-htcpld",
+        },
+};
+
+static int __init htcpld_core_init(void)
+{
+        int ret;
+
+        /* Register the I2C Chip driver */
+        ret = i2c_add_driver(&htcpld_chip_driver);
+        if (ret)
+                return ret;
+
+        /* Probe for our chips */
+        return platform_driver_probe(&htcpld_core_driver, htcpld_core_probe);
+}
+
+static void __exit htcpld_core_exit(void)
+{
+        i2c_del_driver(&htcpld_chip_driver);
+        platform_driver_unregister(&htcpld_core_driver);
+}
+
+module_init(htcpld_core_init);
+module_exit(htcpld_core_exit);
+
+MODULE_AUTHOR("Cory Maccarrone <darkstar6262@gmail.com>");
+MODULE_DESCRIPTION("I2C HTC PLD Driver");
+MODULE_LICENSE("GPL");
+