mts-io: clean up accessory card support

	use custom kernel config option MTS_NUM_ACCESSORY_PORTS to find out how many slots exist
	(mostly) dynamically handle any number of accessory cards
	streamline code to make it easier to add accessory cards in the future

1 files changed, 333 insertions, 219 deletions

diff --git a/io-module/mtac_gpiob.c b/io-module/mtac_gpiob.c
index 5a592b7..728634d 100644
--- a/io-module/mtac_gpiob.c
+++ b/io-module/mtac_gpiob.c
@@ -1,22 +1,130 @@
+struct spi_device *gpiob_spi[NUM_AP][3];
+struct spi_driver gpiob_spi_drivers[NUM_AP][3];
+
+static u8 spi_ap_dout_value;
+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;
+}
+
+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 = 0x00;
+		spi_writen(gpiob_spi[port_index][dev], &spi_ap_dout_value, 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;
+}
+
+// Is there a way to make this dynamic as well?
 struct gpio_pin *ap_gpio_pin_by_attr_name(const char *name) {
 	struct gpio_pin *pin;
 	char *pin_attr_name;
 
-	if (!strcmp(name, "ap1-led1")) {
+	if (!strcmp(name, "ap-led1:1")) {
 		pin_attr_name = "ap1-gpio3";
-	} else if (!strcmp(name, "ap1-led2")) {
+	} else if (!strcmp(name, "ap-led2:1")) {
 		pin_attr_name = "ap1-gpio4";
-	} else if (!strcmp(name, "ap1-dout-enable")) {
+	} else if (!strcmp(name, "ap-dout-enable:1")) {
 		pin_attr_name = "ap1-gpio1";
-	} else if (!strcmp(name, "ap1-reset")) {
+	} else if (!strcmp(name, "ap-reset:1")) {
 		pin_attr_name = "ap1-reset";
-	} else if (!strcmp(name, "ap2-led1")) {
+	} else if (!strcmp(name, "ap-led1:2")) {
 		pin_attr_name = "ap2-gpio3";
-	} else if (!strcmp(name, "ap2-led2")) {
+	} else if (!strcmp(name, "ap-led2:2")) {
 		pin_attr_name = "ap2-gpio4";
-	} else if (!strcmp(name, "ap2-dout-enable")) {
+	} else if (!strcmp(name, "ap-dout-enable:2")) {
 		pin_attr_name = "ap2-gpio1";
-	} else if (!strcmp(name, "ap2-reset")) {
+	} else if (!strcmp(name, "ap-reset:2")) {
 		pin_attr_name = "ap2-reset";
 	} else {
 		log_error("accessory card attribute %s not available", name);
@@ -35,8 +143,8 @@ struct gpio_pin *ap_gpio_pin_by_attr_name(const char *name) {
 }
 
 
-static ssize_t mts_attr_show_ap_gpio_pin(struct device *dev,
-			struct device_attribute *attr,
+static ssize_t mts_attr_show_ap_gpio_pin(struct kobject *kobj,
+			struct kobj_attribute *attr,
 			char *buf)
 {
 	int value;
@@ -63,8 +171,8 @@ static ssize_t mts_attr_show_ap_gpio_pin(struct device *dev,
 	return sprintf(buf, "%d\n", value);
 }
 
-static ssize_t mts_attr_store_ap_gpio_pin(struct device *dev,
-		struct device_attribute *attr, const char *buf, size_t count)
+static ssize_t mts_attr_store_ap_gpio_pin(struct kobject *kobj,
+		struct kobj_attribute *attr, const char *buf, size_t count)
 {
 	int value;
 	struct gpio_pin *pin = ap_gpio_pin_by_attr_name(attr->attr.name);
@@ -90,46 +198,29 @@ static ssize_t mts_attr_store_ap_gpio_pin(struct device *dev,
 	return count;
 }
 
-static ssize_t mts_attr_show_ap_din(struct device *dev, struct device_attribute *attr, char *buf)
+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;
-	struct spi_device* spi_dev;
 
-	if (strstr(attr->attr.name, ":0")) {
-		if (!spi_ap1_din_dev) {
-			log_error("accessory card 1 din device not present");
-			return -ENODEV;
-		}
-
-		spi_dev = spi_ap1_din_dev;
-	} else if (strstr(attr->attr.name, ":1")) {
-		if (!spi_ap2_din_dev) {
-			log_error("accessory card 2 din device not present");
-			return -ENODEV;
-		}
-
-		spi_dev = spi_ap2_din_dev;
-	} else {
-		log_error("unknown din device %s", attr->attr.name);
-		return -ENODEV;
+	sscanf(attr->attr.name, "din%d:%d", &channel, &port);
+	port_index = port - 1;
+	if (channel < 0 || channel > 3) {
+		log_error("channel [%d] is invalid", channel);
+		return -ENOENT;
 	}
-
-	if (strstr(attr->attr.name, "din0")) {
-		bit = BIT(0);
-	} else if (strstr(attr->attr.name, "din1")) {
-		bit = BIT(1);
-	} else if (strstr(attr->attr.name, "din2")) {
-		bit = BIT(2);
-	} else if (strstr(attr->attr.name, "din3")) {
-		bit = BIT(3);
-	} else {
-		log_error("accessory card din attr does not exist");
+	if (port < 1 || port > NUM_AP) {
+		log_error("port [%d] is invalid", port);
 		return -ENOENT;
 	}
 
-	tmp = spi_readn(spi_dev, &byte, 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;
@@ -140,46 +231,29 @@ static ssize_t mts_attr_show_ap_din(struct device *dev, struct device_attribute
 	return sprintf(buf, "%d\n", tmp);
 }
 
-static ssize_t mts_attr_store_ap_dout(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
+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;
-	struct spi_device* spi_dev;
-
-	if (strstr(attr->attr.name, ":0")) {
-		if (!spi_ap1_dout_dev) {
-			log_error("accessory card 1 dout device not present");
-			return -ENODEV;
-		}
 
-		spi_dev = spi_ap1_dout_dev;
-	} else if (strstr(attr->attr.name, ":1")) {
-		if (!spi_ap2_dout_dev) {
-			log_error("accessory card 2 dout device not present");
-			return -ENODEV;
-		}
-
-		spi_dev = spi_ap2_dout_dev;
-	} else {
-		log_error("unknown dout device %s", attr->attr.name);
-		return -ENODEV;
+	sscanf(attr->attr.name, "dout%d:%d", &channel, &port);
+	port_index = port - 1;
+	if (channel < 0 || channel > 3) {
+		log_error("channel [%d] is invalid", channel);
+		return -ENOENT;
 	}
-
-	if (strstr(attr->attr.name, "dout0")) {
-		bit = BIT(0);
-	} else if (strstr(attr->attr.name, "dout1")) {
-		bit = BIT(1);
-	} else if (strstr(attr->attr.name, "dout2")) {
-		bit = BIT(2);
-	} else if (strstr(attr->attr.name, "dout3")) {
-		bit = BIT(3);
-	} else {
-		log_error("accessory card dout attr does not exist");
+	if (port < 1 || port > NUM_AP) {
+		log_error("port [%d] is invalid", port);
 		return -ENOENT;
 	}
 
+	bit = BIT(channel);
+
 	if (sscanf(buf, "%i", &value) != 1) {
-		log_error("accessory card dout attr invalid argument");
+		log_error("accessory card dout attr invalid argument [%d]", value);
 		return -EINVAL;
 	}
 
@@ -191,51 +265,32 @@ static ssize_t mts_attr_store_ap_dout(struct device *dev, struct device_attribut
 		spi_ap_dout_value |= bit;
 	}
 
-	spi_writen(spi_dev, &spi_ap_dout_value, 1);
+	spi_writen(gpiob_spi[port_index][dout], &spi_ap_dout_value, 1);
 
 	mutex_unlock(&spi_ap_dout_mutex);
 
 	return count;
 }
 
-static ssize_t mts_attr_show_ap_dout(struct device *dev, struct device_attribute *attr, char *buf)
+static ssize_t mts_attr_show_ap_dout(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
 {
 	int value;
+	int channel;
+	int port;
 	u8 bit;
-	struct spi_device* spi_dev;
 
-	if (strstr(attr->attr.name, ":0")) {
-		if (!spi_ap1_dout_dev) {
-			log_error("accessory card 1 dout device not present");
-			return -ENODEV;
-		}
-
-		spi_dev = spi_ap1_dout_dev;
-	} else if (strstr(attr->attr.name, ":1")) {
-		if (!spi_ap2_dout_dev) {
-			log_error("accessory card 2 dout device not present");
-			return -ENODEV;
-		}
-
-		spi_dev = spi_ap2_dout_dev;
-	} else {
-		log_error("unknown dout device %s", attr->attr.name);
-		return -ENODEV;
+	sscanf(attr->attr.name, "dout%d:%d", &channel, &port);
+	if (channel < 0 || channel > 3) {
+		log_error("channel [%d] is invalid", channel);
+		return -ENOENT;
 	}
-
-	if (strstr(attr->attr.name, "dout0")) {
-		bit = BIT(0);
-	} else if (strstr(attr->attr.name, "dout1")) {
-		bit = BIT(1);
-	} else if (strstr(attr->attr.name, "dout2")) {
-		bit = BIT(2);
-	} else if (strstr(attr->attr.name, "dout3")) {
-		bit = BIT(3);
-	} else {
-		log_error("accessory card dout attr does not exist");
+	if (port < 1 || port > NUM_AP) {
+		log_error("port [%d] is invalid", port);
 		return -ENOENT;
 	}
 
+	bit = BIT(channel);
+
 	mutex_lock(&spi_ap_dout_mutex);
 
 	value = spi_ap_dout_value & bit ? 0 : 1;
@@ -245,48 +300,30 @@ static ssize_t mts_attr_show_ap_dout(struct device *dev, struct device_attribute
 	return sprintf(buf, "%d\n", value);
 }
 
-static ssize_t mts_attr_show_ap_adc(struct device *dev, struct device_attribute *attr, char *buf)
+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];
-	struct spi_device* spi_dev;
 
 	memset(tx, 0, sizeof(tx));
 	memset(rx, 0, sizeof(rx));
 
-	if (strstr(attr->attr.name, ":0")) {
-		if (!spi_ap1_adc_dev) {
-			log_error("accessory card 1 adc device not present");
-			return -ENODEV;
-		}
-
-		spi_dev = spi_ap1_adc_dev;
-	} else if (strstr(attr->attr.name, ":1")) {
-		if (!spi_ap2_adc_dev) {
-			log_error("accessory card 2 adc device not present");
-			return -ENODEV;
-		}
-
-		spi_dev = spi_ap2_adc_dev;
-	} else {
-		log_error("unknown adc device %s", attr->attr.name);
-		return -ENODEV;
+	sscanf(attr->attr.name, "adc%d:%d", &channel, &port);
+	port_index = port - 1;
+	if (channel < 0 || channel > 2) {
+		log_error("channel [%d] is invalid", channel);
+		return -ENOENT;
 	}
-
-	if (strstr(attr->attr.name, "adc0")) {
-		channel = 0;
-	} else if (strstr(attr->attr.name, "adc1")) {
-		channel = 1;
-	} else if (strstr(attr->attr.name, "adc2")) {
-		channel = 2;
-	} else {
-		log_error("accessory card adc attr does not exist");
+	if (port < 1 || port > NUM_AP) {
+		log_error("port [%d] is invalid", port);
 		return -ENOENT;
 	}
 
@@ -294,7 +331,7 @@ static ssize_t mts_attr_show_ap_adc(struct device *dev, struct device_attribute
 	tx_data = manual_mode | ((channel << 7) & channel_mask);
 	tx[0] = tx_data >> 8;
 	tx[1] = tx_data & 0xFF;
-	tmp = spi_writen(spi_dev, tx, 2);
+	tmp = spi_writen(gpiob_spi[port_index][adc], tx, 2);
 	if (tmp) {
 		log_error("spi_write failed %d", tmp);
 		return tmp;
@@ -305,14 +342,14 @@ static ssize_t mts_attr_show_ap_adc(struct device *dev, struct device_attribute
 	 * the ADC just needs the clock running so it can convert */
 	tx[0] = 0;
 	tx[1] = 0;
-	tmp = spi_writen(spi_dev, tx, 2);
+	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(spi_dev, rx, 2);
+	tmp = spi_readn(gpiob_spi[port_index][adc], rx, 2);
 	if (tmp) {
 		log_error("spi_read failed %d", tmp);
 		return tmp;
@@ -322,88 +359,165 @@ static ssize_t mts_attr_show_ap_adc(struct device *dev, struct device_attribute
 	return sprintf(buf, "%lu\n", (unsigned long) rx_data);
 }
 
-/* accessory port 1 gpiob attributes */
-static DEVICE_ATTR_RO_MTS(dev_attr_ap1_gpio_din0, "din0:0", mts_attr_show_ap_din);
-static DEVICE_ATTR_RO_MTS(dev_attr_ap1_gpio_din1, "din1:0", mts_attr_show_ap_din);
-static DEVICE_ATTR_RO_MTS(dev_attr_ap1_gpio_din2, "din2:0", mts_attr_show_ap_din);
-static DEVICE_ATTR_RO_MTS(dev_attr_ap1_gpio_din3, "din3:0", mts_attr_show_ap_din);
-static DEVICE_ATTR_MTS(dev_attr_ap1_gpio_dout0, "dout0:0", mts_attr_show_ap_dout, mts_attr_store_ap_dout);
-static DEVICE_ATTR_MTS(dev_attr_ap1_gpio_dout1, "dout1:0", mts_attr_show_ap_dout, mts_attr_store_ap_dout);
-static DEVICE_ATTR_MTS(dev_attr_ap1_gpio_dout2, "dout2:0", mts_attr_show_ap_dout, mts_attr_store_ap_dout);
-static DEVICE_ATTR_MTS(dev_attr_ap1_gpio_dout3, "dout3:0", mts_attr_show_ap_dout, mts_attr_store_ap_dout);
-static DEVICE_ATTR_RO_MTS(dev_attr_ap1_gpio_adc0, "adc0:0", mts_attr_show_ap_adc);
-static DEVICE_ATTR_RO_MTS(dev_attr_ap1_gpio_adc1, "adc1:0", mts_attr_show_ap_adc);
-static DEVICE_ATTR_RO_MTS(dev_attr_ap1_gpio_adc2, "adc2:0", mts_attr_show_ap_adc);
-static DEVICE_ATTR_MTS(dev_attr_ap1_gpio_led1, "ap1-led1", mts_attr_show_ap_gpio_pin, mts_attr_store_ap_gpio_pin);
-static DEVICE_ATTR_MTS(dev_attr_ap1_gpio_led2, "ap1-led2", mts_attr_show_ap_gpio_pin, mts_attr_store_ap_gpio_pin);
-static DEVICE_ATTR_MTS(dev_attr_ap1_gpio_oe, "ap1-dout-enable", mts_attr_show_ap_gpio_pin, mts_attr_store_ap_gpio_pin);
-static DEVICE_ATTR_MTS(dev_attr_ap1_reset, "ap1-reset", mts_attr_show_ap_gpio_pin, mts_attr_store_ap_gpio_pin);
-
-static int ap1_gpio_attributes_size = 15;		// not including NULL at end
-
-static struct attribute *ap1_gpio_attributes[] = {
-	&dev_attr_ap1_reset.attr,
-
-	&dev_attr_ap1_gpio_oe.attr,			// gpio1
-	&dev_attr_ap1_gpio_led1.attr,		// gpio3
-	&dev_attr_ap1_gpio_led2.attr,		// gpio4
-
-	&dev_attr_ap1_gpio_din0.attr,
-	&dev_attr_ap1_gpio_din1.attr,
-	&dev_attr_ap1_gpio_din2.attr,
-	&dev_attr_ap1_gpio_din3.attr,
-
-	&dev_attr_ap1_gpio_dout0.attr,
-	&dev_attr_ap1_gpio_dout1.attr,
-	&dev_attr_ap1_gpio_dout2.attr,
-	&dev_attr_ap1_gpio_dout3.attr,
-
-	&dev_attr_ap1_gpio_adc0.attr,
-	&dev_attr_ap1_gpio_adc1.attr,
-	&dev_attr_ap1_gpio_adc2.attr,
-
-	NULL,
-};
+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
+static int ap_gpiob_attrs_size = 15;
+
+static bool gpiob_setup(enum ap port) {
+	int i;
+	int port_index = port - 1;
+	struct kobj_attribute *attr;
+	char buf[32];
+
+	log_info("loading GPIOB accessory card in port %d", port);
+
+	if (device_attrs_size + ap_gpiob_attrs_size >= device_attrs_max_size) {
+		log_error("can't load GPIOB accessory card in port %d - not enough room for attributes", port);
+		return false;
+	}
+
+	// add digital inputs
+	for (i = 0; i < 4; i++) {
+		sprintf(buf, "din%d:%d", i, port);
+		attr = 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;
+		device_attrs[device_attrs_size++] = &attr->attr;
+	}
+
+	// add digital outputs
+	for (i = 0; i < 4; i++) {
+		sprintf(buf, "dout%d:%d", i, port);
+		attr = create_attribute(buf, MTS_ATTR_MODE_RW);
+		if (! attr) {
+			log_error("failed to create attribute[%s]", buf);
+			return false;
+		}
+		attr->show = mts_attr_show_ap_dout;
+		attr->store = mts_attr_store_ap_dout;
+		device_attrs[device_attrs_size++] = &attr->attr;
+	}
+
+	// add analog to digital
+	for (i = 0; i < 3; i++) {
+		sprintf(buf, "adc%d:%d", i, port);
+		attr = 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_adc;
+		device_attrs[device_attrs_size++] = &attr->attr;
+	}
+
+	// add LEDs
+	for (i = 1; i <= 2; i++) {
+		sprintf(buf, "ap-led%d:%d", i, port);
+		attr = create_attribute(buf, MTS_ATTR_MODE_RW);
+		if (! attr) {
+			log_error("failed to create attribute[%s]", buf);
+			return false;
+		}
+		attr->show = mts_attr_show_ap_gpio_pin;
+		attr->store = mts_attr_store_ap_gpio_pin;
+		device_attrs[device_attrs_size++] = &attr->attr;
+	}
+
+	// misc attributes
+	sprintf(buf, "ap-dout-enable:%d", port);
+	attr = create_attribute(buf, MTS_ATTR_MODE_RW);
+	if (! attr) {
+		log_error("failed to create attribute[%s]", buf);
+		return false;
+	}
+	attr->show = mts_attr_show_ap_gpio_pin;
+	attr->store = mts_attr_store_ap_gpio_pin;
+	device_attrs[device_attrs_size++] = &attr->attr;
+
+	sprintf(buf, "ap-reset:%d", port);
+	attr = create_attribute(buf, MTS_ATTR_MODE_RW);
+	if (! attr) {
+		log_error("failed to create attribute[%s]", buf);
+		return false;
+	}
+	attr->show = mts_attr_show_ap_gpio_pin;
+	attr->store = mts_attr_store_ap_gpio_pin;
+	device_attrs[device_attrs_size++] = &attr->attr;
+
+	// 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]", buf);
+		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]", buf);
+		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]", buf);
+		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;
+	}
+	return true;
+}
+
+static bool gpiob_teardown(enum ap port) {
+	int port_index = port - 1;
+
+	// do we need to clean up allocated memory here as well?
+	log_info("unloading GPIOB accessory card in port %d", port);
+	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]);
+	return true;
+}
 
-/* accessory port 2 gpiob attributes */
-static DEVICE_ATTR_RO_MTS(dev_attr_ap2_gpio_din0, "din0:1", mts_attr_show_ap_din);
-static DEVICE_ATTR_RO_MTS(dev_attr_ap2_gpio_din1, "din1:1", mts_attr_show_ap_din);
-static DEVICE_ATTR_RO_MTS(dev_attr_ap2_gpio_din2, "din2:1", mts_attr_show_ap_din);
-static DEVICE_ATTR_RO_MTS(dev_attr_ap2_gpio_din3, "din3:1", mts_attr_show_ap_din);
-static DEVICE_ATTR_MTS(dev_attr_ap2_gpio_dout0, "dout0:1", mts_attr_show_ap_dout, mts_attr_store_ap_dout);
-static DEVICE_ATTR_MTS(dev_attr_ap2_gpio_dout1, "dout1:1", mts_attr_show_ap_dout, mts_attr_store_ap_dout);
-static DEVICE_ATTR_MTS(dev_attr_ap2_gpio_dout2, "dout2:1", mts_attr_show_ap_dout, mts_attr_store_ap_dout);
-static DEVICE_ATTR_MTS(dev_attr_ap2_gpio_dout3, "dout3:1", mts_attr_show_ap_dout, mts_attr_store_ap_dout);
-static DEVICE_ATTR_RO_MTS(dev_attr_ap2_gpio_adc0, "adc0:1", mts_attr_show_ap_adc);
-static DEVICE_ATTR_RO_MTS(dev_attr_ap2_gpio_adc1, "adc1:1", mts_attr_show_ap_adc);
-static DEVICE_ATTR_RO_MTS(dev_attr_ap2_gpio_adc2, "adc2:1", mts_attr_show_ap_adc);
-static DEVICE_ATTR_MTS(dev_attr_ap2_gpio_led1, "ap2-led1", mts_attr_show_ap_gpio_pin, mts_attr_store_ap_gpio_pin);
-static DEVICE_ATTR_MTS(dev_attr_ap2_gpio_led2, "ap2-led2", mts_attr_show_ap_gpio_pin, mts_attr_store_ap_gpio_pin);
-static DEVICE_ATTR_MTS(dev_attr_ap2_gpio_oe, "ap2-dout-enable", mts_attr_show_ap_gpio_pin, mts_attr_store_ap_gpio_pin);
-static DEVICE_ATTR_MTS(dev_attr_ap2_reset, "ap2-reset", mts_attr_show_ap_gpio_pin, mts_attr_store_ap_gpio_pin);
-
-static int ap2_gpio_attributes_size = 15;		// not including NULL at end
-
-static struct attribute *ap2_gpio_attributes[] = {
-	&dev_attr_ap2_reset.attr,
-
-	&dev_attr_ap2_gpio_oe.attr,			// gpio1
-	&dev_attr_ap2_gpio_led1.attr,		// gpio3
-	&dev_attr_ap2_gpio_led2.attr,		// gpio4
-
-	&dev_attr_ap2_gpio_din0.attr,
-	&dev_attr_ap2_gpio_din1.attr,
-	&dev_attr_ap2_gpio_din2.attr,
-	&dev_attr_ap2_gpio_din3.attr,
-
-	&dev_attr_ap2_gpio_dout0.attr,
-	&dev_attr_ap2_gpio_dout1.attr,
-	&dev_attr_ap2_gpio_dout2.attr,
-	&dev_attr_ap2_gpio_dout3.attr,
-
-	&dev_attr_ap2_gpio_adc0.attr,
-	&dev_attr_ap2_gpio_adc1.attr,
-	&dev_attr_ap2_gpio_adc2.attr,
-
-	NULL,
+static struct ap_info gpiob_info = {
+	.product_id = MTAC_GPIOB_0_0,
+	.setup = &gpiob_setup,
+	.teardown = &gpiob_teardown
 };