mtac gpiob derived from mts-io 2.2.21.0.0

1 files changed, 809 insertions, 0 deletions

diff --git a/mtac_gpiob.c b/mtac_gpiob.c
new file mode 100644
index 0000000..69e7388
--- /dev/null
+++ b/mtac_gpiob.c
@@ -0,0 +1,809 @@
+#define DRIVER_VERSION  "v1.0.0"
+#define DRIVER_AUTHOR   "John Klug <john.klug@multitech.com>"
+#define DRIVER_DESC "MTS General Purpose I/O Accessory Card"
+#define DRIVER_NAME "mtac-gpiob"
+
+#include <linux/types.h>
+#include <linux/gpio.h>
+#include <linux/platform_device.h>
+#include <linux/kmod.h>
+#include <linux/bitops.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/spi/spi.h>
+#include <linux/mtac.h>
+#include <linux/mts_io.h>
+
+static struct gpio_pin gpio_pins_mtcdt_mtac_gpiob[] = {
+	// gpio pins for Accessory Card 1
+	{
+		.name = "AP1_RESET",
+		.pin = {
+			.gpio = AT91_PIN_PB12,
+			.flags = GPIOF_OUT_INIT_HIGH,
+			.label = "ap1-reset",
+		}
+	},
+	{
+		.name = "AP1_GPIO1",
+		.pin = {
+			.gpio = AT91_PIN_PC6,
+			.flags = GPIOF_OUT_INIT_LOW,
+			.label = "ap1-gpio1",
+		},
+		.active_low = 1,
+	},
+	{
+		.name = "AP1_GPIO2",
+		.pin = {
+			.gpio = AT91_PIN_PC7,
+			.flags = GPIOF_OUT_INIT_LOW,
+			.label = "ap1-gpio2",
+		}
+	},
+	{
+		.name = "AP1_GPIO3",
+		.pin = {
+			.gpio = AT91_PIN_PC8,
+			.flags = GPIOF_OUT_INIT_LOW,
+			.label = "ap1-gpio3",
+		}
+	},
+	{
+		.name = "AP1_GPIO4",
+		.pin = {
+			.gpio = AT91_PIN_PC9,
+			.flags = GPIOF_OUT_INIT_LOW,
+			.label = "ap1-gpio4",
+		}
+	},
+	{
+		.name = "AP1_INTERRUPT1",
+		.pin = {
+			.gpio = AT91_PIN_PB14,
+			.flags = GPIOF_IN,
+			.label = "ap1-interrupt1",
+		}
+	},
+	{
+		.name = "AP1_INTERRUPT2",
+		.pin = {
+			.gpio = AT91_PIN_PB15,
+			.flags = GPIOF_IN,
+			.label = "ap1-interrupt2",
+		}
+	},
+	{
+		.name = "AP1_GPS_PPS",
+		.pin = {
+			.gpio = AT91_PIN_PA29,
+			.flags = GPIOF_IN,
+			.label = "ap1-gps-pps",
+		}
+	},
+
+	// gpio pins for Accessory Card 2
+	{
+		.name = "AP2_RESET",
+		.pin = {
+			.gpio = AT91_PIN_PB13,
+			.flags = GPIOF_OUT_INIT_HIGH,
+			.label = "ap2-reset",
+		}
+	},
+	{
+		.name = "AP2_GPIO1",
+		.pin = {
+			.gpio = AT91_PIN_PC20,
+			.flags = GPIOF_OUT_INIT_LOW,
+			.label = "ap2-gpio1",
+		},
+		.active_low = 1,
+	},
+	{
+		.name = "AP2_GPIO2",
+		.pin = {
+			.gpio = AT91_PIN_PC21,
+			.flags = GPIOF_OUT_INIT_LOW,
+			.label = "ap2-gpio2",
+		}
+	},
+	{
+		.name = "AP2_GPIO3",
+		.pin = {
+			.gpio = AT91_PIN_PC22,
+			.flags = GPIOF_OUT_INIT_LOW,
+			.label = "ap2-gpio3",
+		}
+	},
+	{
+		.name = "AP2_GPIO4",
+		.pin = {
+			.gpio = AT91_PIN_PC23,
+			.flags = GPIOF_OUT_INIT_LOW,
+			.label = "ap2-gpio4",
+		}
+	},
+	{
+		.name = "AP2_INTERRUPT1",
+		.pin = {
+			.gpio = AT91_PIN_PB17,
+			.flags = GPIOF_IN,
+			.label = "ap2-interrupt1",
+		}
+	},
+	{
+		.name = "AP2_INTERRUPT2",
+		.pin = {
+			.gpio = AT91_PIN_PB18,
+			.flags = GPIOF_IN,
+			.label = "ap2-interrupt2",
+		}
+	},
+	{
+		.name = "AP2_GPS_PPS",
+		.pin = {
+			.gpio = AT91_PIN_PA6,
+			.flags = GPIOF_IN,
+			.label = "ap2-gps-pps",
+		}
+	},
+
+	{ },
+};
+
+enum spi_devices {
+	din = 0,
+	dout = 1,
+	adc = 2,
+};
+
+struct spi_device *gpiob_spi[NUM_AP][3];
+struct spi_driver gpiob_spi_drivers[NUM_AP][3];
+
+static u8 spi_ap_dout_value[NUM_AP];
+static DEFINE_MUTEX(spi_ap_dout_mutex);
+static unsigned int ap_dout_max_speed_hz = 1 * 1000 * 1000;
+module_param(ap_dout_max_speed_hz, uint, S_IRUGO);
+MODULE_PARM_DESC(
+	ap_dout_max_speed_hz,
+	"Maximum clock rate to be used with this device (default: 1 MHz)"
+);
+
+static unsigned int ap_din_max_speed_hz = 1 * 1000 * 1000;
+module_param(ap_din_max_speed_hz, uint, S_IRUGO);
+MODULE_PARM_DESC(
+	ap_din_max_speed_hz,
+	"Maximum clock rate to be used with this device (default: 1 MHz)"
+);
+
+static unsigned int ap_adc_max_speed_hz = 20 * 1000 * 1000;
+module_param(ap_adc_max_speed_hz, uint, S_IRUGO);
+MODULE_PARM_DESC(
+	ap_adc_max_speed_hz,
+	"Maximum clock rate to be used with this device (default: 20 MHz)"
+);
+
+static bool gpiob_get_dev_info_from_modalias(const char* modalias, int* port, char* buf) {
+	sscanf(modalias, "mts-io-ap%d-%s", port, buf);
+
+	return true;
+}
+
+/* Generic SPI functions */
+static inline int spi_writen(struct spi_device *spi, const u8 *buf, size_t len)
+{
+	int tmp;
+	u8 *tx;
+
+	tx = kmalloc(len, GFP_KERNEL);
+	if (!tx) {
+		return -ENOMEM;
+	}
+
+	memcpy(tx, buf, len);
+	tmp = spi_write(spi, tx, len);
+
+	kfree(tx);
+
+	return tmp;
+}
+
+static inline int spi_readn(struct spi_device *spi, u8 *buf, size_t len)
+{
+	int tmp;
+	u8 *rx;
+
+	rx = kmalloc(len, GFP_KERNEL);
+	if (!rx) {
+		return -ENOMEM;
+	}
+
+	tmp = spi_read(spi, rx, len);
+	memcpy(buf, rx, len);
+
+	kfree(rx);
+
+	return tmp;
+}
+
+static int mts_spi_ap_probe(struct spi_device *spi)
+{
+	int tmp;
+	int port;
+	int port_index;
+	char buf[16];
+	enum spi_devices dev;
+
+	gpiob_get_dev_info_from_modalias(spi->modalias, &port, buf);
+	port_index = port - 1;
+	if (port < 1 || port > NUM_AP) {
+		log_error("port %d is invalid", port);
+		return -ENODEV;
+	}
+
+	if (strstr(buf, "dout")) {
+		dev = dout;
+		spi->max_speed_hz = ap_dout_max_speed_hz;
+		spi->mode = 0;
+	} else if (strstr(buf, "din")) {
+		dev = din;
+		spi->max_speed_hz = ap_din_max_speed_hz;
+		spi->mode = SPI_CPOL;
+	} else if (strstr(buf, "adc")) {
+		dev = adc;
+		spi->max_speed_hz = ap_adc_max_speed_hz;
+		spi->mode = 0;
+	} else {
+		log_error("unknown gpiob spi device type [%s]", buf);
+		return -ENODEV;
+	}
+
+	gpiob_spi[port_index][dev] = spi;
+
+	tmp = spi_setup(gpiob_spi[port_index][dev]);
+	if (tmp < 0) {
+		log_error("spi_setup ap %d [%s] failed", port, buf);
+		return tmp;
+	}
+
+	if (dev == dout) {
+		spi_ap_dout_value[port_index] = 0x00;
+		spi_writen(gpiob_spi[port_index][dev], &spi_ap_dout_value[port_index], 1);
+	}
+
+	return 0;
+}
+
+static int mts_spi_ap_remove(struct spi_device *spi)
+{
+	int port;
+	int port_index;
+	char buf[16];
+
+	gpiob_get_dev_info_from_modalias(spi->modalias, &port, buf);
+	port_index = port - 1;
+	if (port < 1 || port > NUM_AP) {
+		log_error("port %d is invalid", port);
+		return -ENODEV;
+	}
+
+	if (strstr(buf, "dout")) {
+		gpiob_spi[port_index][dout] = NULL;
+	} else if (strstr(buf, "din")) {
+		gpiob_spi[port_index][din] = NULL;
+	} else if (strstr(buf, "adc")) {
+		gpiob_spi[port_index][adc] = NULL;
+	} else {
+		log_error("unknown gpiob spi device type [%s]", buf);
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+static char* gpiob_gpio_pin_name_by_attr_name(const char* name, int port) {
+	switch (port) {
+		case port_1:
+			if (! strcmp(name, "led1")) {
+				return "ap1-gpio3";
+			} else if (! strcmp(name, "led2")) {
+				return "ap1-gpio4";
+			} else if (! strcmp(name, "dout-enable")) {
+				return "ap1-gpio1";
+			} else if (! strcmp(name, "reset")) {
+				return "ap1-reset";
+			} else {
+				log_error("attribute name [%s] is invalid for GPIOB in port %d", name, port);
+				return "";
+			}
+
+		case port_2:
+			if (! strcmp(name, "led1")) {
+				return "ap2-gpio3";
+			} else if (! strcmp(name, "led2")) {
+				return "ap2-gpio4";
+			} else if (! strcmp(name, "dout-enable")) {
+				return "ap2-gpio1";
+			} else if (! strcmp(name, "reset")) {
+				return "ap2-reset";
+			} else {
+				log_error("attribute name [%s] is invalid for GPIOB in port %d", name, port);
+				return "";
+			}
+	}
+	log_error("gpiob: Invalid port number");
+	return "";
+}
+
+static ssize_t mts_attr_show_ap_din(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
+{
+	int tmp;
+	int channel;
+	int port;
+	int port_index;
+	u8 bit;
+	u8 byte;
+
+	sscanf(attr->attr.name, "din%d", &channel);
+	if (channel < 0 || channel > 3) {
+		log_error("channel %d is invalid", channel);
+		return -ENOENT;
+	}
+
+	port = mtac_port_from_kobject(kobj);
+	if (port < 0) {
+		log_error("mtac_port_from_kobject returned %d", port);
+		return -EINVAL;
+	}
+	port_index = port - 1;
+
+	bit = BIT(channel);
+
+	tmp = spi_readn(gpiob_spi[port_index][din], &byte, 1);
+	if (tmp) {
+		log_error("spi_read failed %d", tmp);
+		return tmp;
+	}
+
+	tmp = byte & bit ? 1 : 0;
+
+	return sprintf(buf, "%d\n", tmp);
+}
+
+static ssize_t mts_attr_store_ap_dout(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t count)
+{
+	int value;
+	int channel;
+	int port;
+	int port_index;
+	u8 bit;
+
+	sscanf(attr->attr.name, "dout%d", &channel);
+	if (channel < 0 || channel > 3) {
+		log_error("channel %d is invalid", channel);
+		return -ENOENT;
+	}
+
+	port = mtac_port_from_kobject(kobj);
+	if (port < 0) {
+		log_error("mtac_port_from_kobject returned %d", port);
+		return -EINVAL;
+	}
+	port_index = port - 1;
+
+	bit = BIT(channel);
+
+	if (sscanf(buf, "%i", &value) != 1) {
+		log_error("accessory card dout attr invalid argument %d", value);
+		return -EINVAL;
+	}
+
+	mutex_lock(&spi_ap_dout_mutex);
+
+	if (value) {
+		spi_ap_dout_value[port_index] &= ~bit;
+	} else {
+		spi_ap_dout_value[port_index] |= bit;
+	}
+
+	spi_writen(gpiob_spi[port_index][dout], &spi_ap_dout_value[port_index], 1);
+
+	mutex_unlock(&spi_ap_dout_mutex);
+
+	return count;
+}
+
+static ssize_t mts_attr_show_ap_dout(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
+{
+	int value;
+	int channel;
+	int port;
+	int port_index;
+	u8 bit;
+
+	sscanf(attr->attr.name, "dout%d", &channel);
+	if (channel < 0 || channel > 3) {
+		log_error("channel %d is invalid", channel);
+		return -ENOENT;
+	}
+
+	port = mtac_port_from_kobject(kobj);
+	if (port < 0) {
+		log_error("mtac_port_from_kobject returned %d", port);
+		return -EINVAL;
+	}
+	port_index = port - 1;
+
+	bit = BIT(channel);
+
+	mutex_lock(&spi_ap_dout_mutex);
+
+	value = spi_ap_dout_value[port_index] & bit ? 0 : 1;
+
+	mutex_unlock(&spi_ap_dout_mutex);
+
+	return sprintf(buf, "%d\n", value);
+}
+
+static ssize_t mts_attr_show_ap_adc(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
+{
+	int tmp;
+	int tx_data;
+	int rx_data;
+	int channel;
+	int port;
+	int port_index;
+	int channel_mask = 0x0180;  /* 0b 0000 0001 1000 0000 */
+	int manual_mode = 0x1840;   /* 0b 0001 1000 0100 0000 */
+	uint8_t tx[2];
+	uint8_t rx[2];
+
+	memset(tx, 0, sizeof(tx));
+	memset(rx, 0, sizeof(rx));
+
+	sscanf(attr->attr.name, "adc%d", &channel);
+	if (channel < 0 || channel > 2) {
+		log_error("channel %d is invalid", channel);
+		return -ENOENT;
+	}
+
+	port = mtac_port_from_kobject(kobj);
+	if (port < 0) {
+		log_error("mtac_port_from_kobject returned %d", port);
+		return -EINVAL;
+	}
+	port_index = port - 1;
+
+	/* 1st transfer to set up (5V reference, channel to read from) */
+	tx_data = manual_mode | ((channel << 7) & channel_mask);
+	tx[0] = tx_data >> 8;
+	tx[1] = tx_data & 0xFF;
+	tmp = spi_writen(gpiob_spi[port_index][adc], tx, 2);
+	if (tmp) {
+		log_error("spi_write failed %d", tmp);
+		return tmp;
+	}
+
+	/* 2nd transfer to clock chip for ADC conversion
+	 * this can be a throw-away read or an empty write,
+	 * the ADC just needs the clock running so it can convert */
+	tx[0] = 0;
+	tx[1] = 0;
+	tmp = spi_writen(gpiob_spi[port_index][adc], tx, 2);
+	if (tmp) {
+		log_error("2nd spi_write failed %d", tmp);
+		return tmp;
+	}
+
+	/* 3rd transfer to read data */
+	tmp = spi_readn(gpiob_spi[port_index][adc], rx, 2);
+	if (tmp) {
+		log_error("spi_read failed %d", tmp);
+		return tmp;
+	}
+	rx_data = ((rx[0] & 0x0F) << 8) | (rx[1] & 0xFF);
+
+	return sprintf(buf, "%lu\n", (unsigned long) rx_data);
+}
+
+static bool gpiob_spi_driver_setup(struct spi_driver *driver, const char *driver_name) {
+	char* name = kstrdup(driver_name, GFP_KERNEL);
+	if (! name) {
+		log_error("GFP_KERNEL dup failed for driver [%s]", driver_name);
+		return false;
+	}
+	driver->driver.name = name;
+	driver->driver.bus = &spi_bus_type;
+	driver->driver.owner = THIS_MODULE;
+	driver->probe = mts_spi_ap_probe;
+	driver->remove = mts_spi_ap_remove;
+
+	return true;
+}
+
+// 4 digital inputs
+// 4 digital outputs
+// 3 analog to digital
+// 2 LEDs
+// 1 digital out enable
+// 1 reset
+// 1 vendor-id
+// 1 product-id
+// 1 device-id
+// 1 hw-version
+// NULL
+static int ap_gpiob_attrs_size = 20;
+
+static bool gpiob_setup(enum ap port) {
+	int i;
+	int port_index = port - 1;
+	int index = 0;
+	int count = 0;
+	int ret;
+	char buf[32];
+	struct kobj_attribute* attr;
+	struct attribute **attrs;
+	struct kobject *subdir;
+
+	log_info("loading GPIOB accessory card in port %d", port);
+
+	sprintf(buf, "ap%d", port);
+	subdir = kobject_create_and_add(buf, &mts_io_platform_device->dev.kobj);
+	if (! subdir) {
+		log_error("kobject_create_and_add for port %d failed", port);
+		return false;
+	}
+
+	mtac_set_port_pins(port_index,gpio_pins_mtcdt_mtac_gpiob,subdir);
+
+	// create the link to the apX directory this card is in
+	// if we're in the first slot, we get plain "gpiob"
+	// if we're in a different slot, we might need to use "gpiob-2" to differentiate
+	if (port > 1) {
+		for (i = 1; i < port; i++) {
+			if (mtac_port_info[i - 1]) {
+				if (strstr(mtac_port_info[i - 1]->product_id, PRODUCT_ID_MTAC_GPIOB)) {
+					count++;
+				}
+			}
+		}
+	}
+	if (count > 0) {
+		sprintf(buf, "gpiob-%d", count + 1);
+	} else {
+		sprintf(buf, "gpiob");
+	}
+	ret = sysfs_create_link(mtac_port_info[port_index]->subdirs->parent, mtac_port_info[port_index]->subdirs, buf);
+	if (ret) {
+		log_error("failed to link [%s] to [%s], %d", buf, mtac_port_info[port_index]->subdirs->name, ret);
+	}
+
+	attrs = kzalloc(sizeof(struct attribute*) * ap_gpiob_attrs_size, GFP_KERNEL);
+	if (! attrs) {
+		log_error("failed to allocate attribute space for port %d", port);
+		return false;
+	}
+
+	// add digital inputs
+	for (i = 0; i < 4; i++) {
+		sprintf(buf, "din%d", i);
+		attr = mtac_create_attribute(buf, MTS_ATTR_MODE_RO);
+		if (! attr) {
+			log_error("failed to create attribute [%s]", buf);
+			return false;
+		}
+		attr->show = mts_attr_show_ap_din;
+		attrs[index++] = &attr->attr;
+	}
+
+	// add digital outputs
+	for (i = 0; i < 4; i++) {
+		sprintf(buf, "dout%d", i);
+		attr = mtac_create_attribute(buf, MTS_ATTR_MODE_RW);
+		if (! attr) {
+			log_error("failed to create attribute [%s] for GPIOB in port %d", buf, port);
+			return false;
+		}
+		attr->show = mts_attr_show_ap_dout;
+		attr->store = mts_attr_store_ap_dout;
+		attrs[index++] = &attr->attr;
+	}
+
+	// add analog to digital
+	for (i = 0; i < 3; i++) {
+		sprintf(buf, "adc%d", i);
+		attr = mtac_create_attribute(buf, MTS_ATTR_MODE_RO);
+		if (! attr) {
+			log_error("failed to create attribute [%s] for GPIOB in port %d", buf, port);
+			return false;
+		}
+		attr->show = mts_attr_show_ap_adc;
+		attrs[index++] = &attr->attr;
+	}
+
+	// add LEDs
+	for (i = 1; i <= 2; i++) {
+		sprintf(buf, "led%d", i);
+		attr = mtac_create_attribute(buf, MTS_ATTR_MODE_RW);
+		if (! attr) {
+			log_error("failed to create attribute [%s] for GPIOB in port %d", buf, port);
+			return false;
+		}
+		attr->show = mtac_attr_show_ap_gpio_pin;
+		attr->store = mtac_attr_store_ap_gpio_pin;
+		attrs[index++] = &attr->attr;
+	}
+
+	// add misc attributes
+	sprintf(buf, "dout-enable");
+	attr = mtac_create_attribute(buf, MTS_ATTR_MODE_RW);
+	if (! attr) {
+		log_error("failed to create attribute [%s] for GPIOB in port %d", buf, port);
+		return false;
+	}
+	attr->show = mtac_attr_show_ap_gpio_pin;
+	attr->store = mtac_attr_store_ap_gpio_pin;
+	attrs[index++] = &attr->attr;
+
+	sprintf(buf, "reset");
+	attr = mtac_create_attribute(buf, MTS_ATTR_MODE_RW);
+	if (! attr) {
+		log_error("failed to create attribute [%s] for GPIOB in port %d", buf, port);
+		return false;
+	}
+	attr->show = mtac_attr_show_ap_gpio_pin;
+	attr->store = mtac_attr_store_ap_gpio_pin;
+	attrs[index++] = &attr->attr;
+
+	// add attributes for eeprom contents
+	if (! mtac_add_product_info_attributes(port, attrs, &index)) {
+		log_error("failed to add product info attributes for GPIOB in port %d", port);
+		return false;
+	}
+
+	attrs[index] = NULL;
+
+	mtac_port_info[port_index]->attr_group.attrs = attrs;
+
+	// setup and register drivers
+	log_debug("registering accessory card %d dout driver", port);
+	sprintf(buf, "mts-io-ap%d-dout", port);
+	if (! gpiob_spi_driver_setup(&gpiob_spi_drivers[port_index][dout], buf)) {
+		log_error("failed to set up spi driver [%s] for GPIOB in port %d", buf, port);
+		return false;
+	}
+	if (spi_register_driver(&gpiob_spi_drivers[port_index][dout])) {
+		log_error("failed to register accessory card %d dout driver", port);
+		spi_unregister_driver(&gpiob_spi_drivers[port_index][dout]);
+		return false;
+	}
+
+	log_debug("registering accessory card %d din driver", port);
+	sprintf(buf, "mts-io-ap%d-din", port);
+	if (! gpiob_spi_driver_setup(&gpiob_spi_drivers[port_index][din], buf)) {
+		log_error("failed to set up spi driver [%s] for GPIOB in port %d", buf, port);
+		return false;
+	}
+	if (spi_register_driver(&gpiob_spi_drivers[port_index][din])) {
+		log_error("failed to register accessory card %d din driver", port);
+		spi_unregister_driver(&gpiob_spi_drivers[port_index][din]);
+		return false;
+	}
+
+	log_debug("registering accessory card %d adc driver", port);
+	sprintf(buf, "mts-io-ap%d-adc", port);
+	if (! gpiob_spi_driver_setup(&gpiob_spi_drivers[port_index][adc], buf)) {
+		log_error("failed to set up spi driver [%s] for GPIOB in port %d", buf, port);
+		return false;
+	}
+	if (spi_register_driver(&gpiob_spi_drivers[port_index][adc])) {
+		log_error("failed to register accessory card %d adc driver", port);
+		spi_unregister_driver(&gpiob_spi_drivers[port_index][adc]);
+		return false;
+	}
+
+	if (sysfs_create_group(mtac_port_info[port_index]->subdirs, &mtac_port_info[port_index]->attr_group)) {
+		log_error("sysfs_create_group failed for GPIOB in port %d", port);
+		return false;
+	}
+
+	return true;
+}
+
+static bool gpiob_teardown(enum ap port) {
+	int i;
+	int port_index = port - 1;
+	struct attribute **attrs = mtac_port_info[port_index]->attr_group.attrs;
+
+	log_info("unloading GPIOB accessory card in port %d", port);
+
+	// clean up allocated memory for attributes
+	for (i = 0; i < ap_gpiob_attrs_size; i++) {
+		if (attrs[i]) {
+			if (attrs[i]->name)
+				kfree(attrs[i]->name);
+
+			kfree(attrs[i]);
+		}
+	}
+
+	kfree(attrs);
+
+	// clean up our "apX/" kobject if it exists
+	if (mtac_port_info[port_index]->subdirs) {
+		kobject_put(mtac_port_info[port_index]->subdirs);
+	}
+
+	// clean up allocated memory for SPI drivers
+	if (gpiob_spi_drivers[port_index][dout].driver.name)
+		kfree(gpiob_spi_drivers[port_index][dout].driver.name);
+	if (gpiob_spi_drivers[port_index][din].driver.name)
+		kfree(gpiob_spi_drivers[port_index][din].driver.name);
+	if (gpiob_spi_drivers[port_index][adc].driver.name)
+		kfree(gpiob_spi_drivers[port_index][adc].driver.name);
+
+	// unregister SPI drivers
+	spi_unregister_driver(&gpiob_spi_drivers[port_index][dout]);
+	spi_unregister_driver(&gpiob_spi_drivers[port_index][din]);
+	spi_unregister_driver(&gpiob_spi_drivers[port_index][adc]);
+	mtac_clear_port_pins(port_index);
+	return true;
+}
+
+bool set_gpiob_info(struct ap_info* info) {
+	snprintf(info->product_id, 32, "%s", PRODUCT_ID_MTAC_GPIOB);
+	info->setup = &gpiob_setup;
+	info->teardown = &gpiob_teardown;
+	info->gpio_pin_name_by_attr_name = &gpiob_gpio_pin_name_by_attr_name;
+
+	return true;
+}
+
+/*
+ * Loop through all the slots, and set up the
+ * mtac-gpiob driver for all slots.
+ */
+static int __init mtac_gpiob_init(void)
+{
+	int slot_count = 0;
+
+	slot_count = mtac_find(set_gpiob_info,PRODUCT_ID_MTAC_GPIOB);
+
+	if (slot_count < 1) {
+		log_debug("No MTAC GPIOB found");
+		if (slot_count < 0)
+			return slot_count;
+		else
+			return -ENXIO;
+
+	}
+
+	return 0;
+}
+
+/* We can only tear down our own device */
+static void __exit mtac_gpiob_exit(void)
+{
+	int port_index;
+	struct mts_ap_eeprom_layout *app;
+
+	for (port_index = 0; port_index < NUM_AP; port_index++) {
+		app = (struct mts_ap_eeprom_layout *)mts_ap_eeprom[port_index];
+        if (app && strstr(app->product_id, PRODUCT_ID_MTAC_GPIOB)) {
+			if (mtac_port_info[port_index]->setup == &gpiob_setup) {
+				mtac_port_info[port_index]->teardown(port_index+1);
+				kfree(mtac_port_info[port_index]);
+			}
+        }
+    }
+	log_info("exiting");
+}
+
+module_init(mtac_gpiob_init);
+module_exit(mtac_gpiob_exit);
+
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_VERSION(DRIVER_VERSION);
+MODULE_LICENSE("GPL");