First pass with working I2C driver. Loads cleanly against real device, but needs a lot of

linux_driver/ai2c_platform_data.h

+#ifndef _AI2C_PLATFORM_DATA_H
+#define _AI2C_PLATFORM_DATA_H
+
+typedef struct arduino_i2c_keyboard_platform_data {
+	int gpio_intr_pin;
+	int *keymap;
+} arduino_i2c_keyboard_platform_data_t;
+
+#endif /* _AI2C_PLATFORM_DATA_H */

linux_driver/arduino_i2c.c

 #include <linux/module.h>
 
 #include <linux/gpio.h>
+#include <linux/i2c.h>
 #include <linux/interrupt.h>
 #include <linux/kernel.h>
+#include <linux/workqueue.h>
 
-#define IRQ_GPIO_PIN	22
+#include "ai2c_platform_data.h"
+
+#define IRQ_GPIO_PIN	9
 #define GPIO_IRQ_NAME	"ai2c_keyboard_irq"
 
 static int irq_num = -1;
 static int count = 0;
+static int up_count = 0;
+struct delayed_work my_work;
+static struct i2c_client *my_client = NULL;	// XXX - FIXME
+
+const int keymap[] = {
+	0,
+};
+
+static void
+ai2c_intr(struct work_struct *work) {
+	if (up_count++ < 10) {
+		printk("ai2c_intr:  entered\n");
+	}
+	if (my_client)
+		i2c_smbus_write_byte_data(my_client, 50, 48);
+	return;
+}
 
 static irqreturn_t
 ai2c_intr_lower(int irq, void *data) {
 	if (count++ < 10) {
 		printk("ai2c_intr_lower:  entered\n");
 	}
+	schedule_delayed_work(&my_work, 25);
 	return IRQ_HANDLED;
 }
 
-int
-ai2c_init(void) {
+static int
+ai2c_probe(struct i2c_client *client, const struct i2c_device_id *id) {
 	int ret;
 	int flags = 0;
 	void *drv_info = NULL;
+	const arduino_i2c_keyboard_platform_data_t *pdata =
+		dev_get_platdata(&client->dev);
 
-	printk(KERN_INFO "Arduino I2C Keyboard Starting\n");
-	ret = gpio_request(IRQ_GPIO_PIN, GPIO_IRQ_NAME);
+	dev_info(&client->dev, "Arduino I2C Keyboard Probe Starting\n");
+	if (!pdata) {
+		dev_err(&client->dev, "No platform present - failing\n");
+		return -EINVAL;
+	}
+
+	ret = gpio_request(pdata->gpio_intr_pin, GPIO_IRQ_NAME);
 	if (ret < 0) {
-		printk(KERN_ERR "ai2c:  IRQ pin reservation failed:  error %d\n", ret);
+		dev_err(&client->dev, "ai2c:  IRQ pin reservation of %d failed:  error %d\n", pdata->gpio_intr_pin, ret);
 		return ret;
 	}
 
-	gpio_direction_input(IRQ_GPIO_PIN);
-	irq_num = gpio_to_irq(IRQ_GPIO_PIN);
+	gpio_direction_input(pdata->gpio_intr_pin);
+	gpio_set_debounce(pdata->gpio_intr_pin, 50);	// 50ms
+
+#ifndef CONFIG_SIERRA
+	/* GPIO exports are broken on Sierra Wireless Linux due to their weird gpiolib mods */
+	gpio_export(pdata->gpio_intr_pin, "arduino_i2c_intr_pin");
+#endif /* CONFIG_SIERRA */
 
-	printk(KERN_INFO "ai2c:  Reserved pin [%d]:  irq = %d\n", IRQ_GPIO_PIN, irq_num);
+	irq_num = gpio_to_irq(pdata->gpio_intr_pin);
 
+	dev_dbg(&client->dev, "ai2c:  Reserved pin [%d]:  irq = %d\n", pdata->gpio_intr_pin, irq_num);
+
+	flags |= IRQF_TRIGGER_FALLING;
 	ret = request_irq(irq_num, ai2c_intr_lower, flags, "ai2c_keyboard", drv_info);
 	if (ret < 0) {
-		printk(KERN_ERR "ai2c:  request_irq failed:  error %d\n", ret);
+		dev_err(&client->dev, "ai2c:  request_irq failed:  error %d\n", ret);
 		return ret;
 	}
 
 	irq_set_irq_type(irq_num, IRQ_TYPE_EDGE_FALLING);
 
+	my_client = client;	// XXX - FIXME - Put in IRQ Info
+
 	return 0;
 }
 
-void
-ai2c_shutdown(void) {
-	printk(KERN_INFO "Arduino I2C Keyboard Shutting Down\n");
+static int
+ai2c_remove(struct i2c_client *client) {
 	if (irq_num > 0) {
 		free_irq(irq_num, ai2c_intr_lower);
 	}
+	return 0;
+}
+
+
+
+static const struct i2c_device_id ai2c_id[] = {
+	{ "ai2c-keys", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, ai2c_id);
+
+static struct i2c_driver ai2c_driver = {
+	.driver = {
+		.name = KBUILD_MODNAME,
+	},
+	.probe    = ai2c_probe,
+	.remove   = ai2c_remove,
+	.id_table = ai2c_id,
+};
+
+int
+ai2c_init(void) {
+	int ret;
+	printk(KERN_INFO "Arduino I2C Keyboard Starting\n");
+	ret = i2c_add_driver(&ai2c_driver);
+	if (ret < 0) {
+		printk(KERN_ERR "Unable to register AI2C keyboard driver\n");
+	}
+	INIT_DELAYED_WORK(&my_work, ai2c_intr);
+	return ret;
+}
+
+void
+ai2c_shutdown(void) {
+	printk(KERN_INFO "Arduino I2C Keyboard Shutting Down\n");
 }
 
 module_init(ai2c_init);