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

8 files changed, 532 insertions, 847 deletions

diff --git a/io-module/Makefile b/io-module/Makefile
index f95a55e..5d036f4 100644
--- a/io-module/Makefile
+++ b/io-module/Makefile
@@ -1,5 +1,4 @@
 obj-m := mts_io.o
-CFLAGS_mts_io.o := ${DAUGHTER_CARD}
 
 clean:
 	rm -f *.ko *.o
diff --git a/io-module/mtac.c b/io-module/mtac.c
new file mode 100644
index 0000000..b9a2520
--- /dev/null
+++ b/io-module/mtac.c
@@ -0,0 +1,22 @@
+static struct kobj_attribute* create_attribute(const char* _name, umode_t _mode) {
+	char* attr_name;
+	struct kobj_attribute* _attr;
+	
+	_attr = kzalloc(sizeof(struct kobj_attribute), GFP_KERNEL);
+	if (! _attr) {
+		log_error("kzalloc of attribute %s failed", _name);
+		return NULL;
+	}
+
+	sysfs_attr_init(_attr);
+	attr_name = kstrdup(_name, GFP_KERNEL);
+	if (! attr_name) {
+		log_error("GFP_KERNEL dup failed for attribute [%s]", _name);
+		return NULL;
+	}
+
+	_attr->attr.name = attr_name;
+	_attr->attr.mode = _mode;
+
+	return _attr;
+}
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
 };
diff --git a/io-module/mtac_mfser.c b/io-module/mtac_mfser.c
index 14eddd1..5871bfe 100644
--- a/io-module/mtac_mfser.c
+++ b/io-module/mtac_mfser.c
@@ -2,13 +2,13 @@ struct gpio_pin *ap_mfser_pin_by_attr_name(const char *name) {
 	struct gpio_pin *pin;
 	char *pin_attr_name;
 
-	if (!strcmp(name, "rs4xx-term-res:0")) {
+	if (!strcmp(name, "rs4xx-term-res:1")) {
 		pin_attr_name = "ap1-gpio3";
-	} else if (!strcmp(name, "rts-override:0")) {
+	} else if (!strcmp(name, "rts-override:1")) {
 		pin_attr_name = "ap1-gpio4";
-	} else if (!strcmp(name, "rs4xx-term-res:1")) {
+	} else if (!strcmp(name, "rs4xx-term-res:2")) {
 		pin_attr_name = "ap2-gpio3";
-	} else if (!strcmp(name, "rts-override:1")) {
+	} else if (!strcmp(name, "rts-override:2")) {
 		pin_attr_name = "ap2-gpio4";
 	} else {
 		log_error("accessory card attribute %s not available", name);
@@ -27,8 +27,8 @@ struct gpio_pin *ap_mfser_pin_by_attr_name(const char *name) {
 }
 
 
-static ssize_t mts_attr_show_ap_mfser_pin(struct device *dev,
-			struct device_attribute *attr,
+static ssize_t mts_attr_show_ap_mfser_pin(struct kobject *kobj,
+			struct kobj_attribute *attr,
 			char *buf)
 {
 	int value;
@@ -55,8 +55,8 @@ static ssize_t mts_attr_show_ap_mfser_pin(struct device *dev,
 	return sprintf(buf, "%d\n", value);
 }
 
-static ssize_t mts_attr_store_ap_mfser_pin(struct device *dev,
-		struct device_attribute *attr, const char *buf, size_t count)
+static ssize_t mts_attr_store_ap_mfser_pin(struct kobject *kobj,
+		struct kobj_attribute *attr, const char *buf, size_t count)
 {
 	int value;
 	struct gpio_pin *pin = ap_mfser_pin_by_attr_name(attr->attr.name);
@@ -82,8 +82,8 @@ static ssize_t mts_attr_store_ap_mfser_pin(struct device *dev,
 	return count;
 }
 
-static ssize_t mts_attr_show_mfser_mode(struct device *dev,
-			struct device_attribute *attr,
+static ssize_t mts_attr_show_mfser_mode(struct kobject *kobj,
+			struct kobj_attribute *attr,
 			char *buf)
 {
 	int ret;
@@ -93,11 +93,11 @@ static ssize_t mts_attr_show_mfser_mode(struct device *dev,
 	struct gpio_pin *pin_modesel0;
 	struct gpio_pin *pin_modesel1;
 
-	if (strstr(attr->attr.name, ":0")) {
+	if (strstr(attr->attr.name, ":1")) {
 		pin_modesel0 = gpio_pin_by_name("AP1_GPIO1");
 		pin_modesel1 = gpio_pin_by_name("AP1_GPIO2");
 	}
-	else if (strstr(attr->attr.name, ":1")) {
+	else if (strstr(attr->attr.name, ":2")) {
 		pin_modesel0 = gpio_pin_by_name("AP2_GPIO1");
 		pin_modesel1 = gpio_pin_by_name("AP2_GPIO2");
 	}
@@ -130,19 +130,19 @@ static ssize_t mts_attr_show_mfser_mode(struct device *dev,
 	return ret;
 }
 
-static ssize_t mts_attr_store_mfser_mode(struct device *dev,
-		struct device_attribute *attr, const char *buf, size_t count)
+static ssize_t mts_attr_store_mfser_mode(struct kobject *kobj,
+		struct kobj_attribute *attr, const char *buf, size_t count)
 {
 	int modesel0;
 	int modesel1;
 	struct gpio_pin *pin_modesel0;
 	struct gpio_pin *pin_modesel1;
 
-	if (strstr(attr->attr.name, ":0")) {
+	if (strstr(attr->attr.name, ":1")) {
 		pin_modesel0 = gpio_pin_by_name("AP1_GPIO1");
 		pin_modesel1 = gpio_pin_by_name("AP1_GPIO2");
 	}
-	else if (strstr(attr->attr.name, ":1")) {
+	else if (strstr(attr->attr.name, ":2")) {
 		pin_modesel0 = gpio_pin_by_name("AP2_GPIO1");
 		pin_modesel1 = gpio_pin_by_name("AP2_GPIO2");
 	}
@@ -184,32 +184,62 @@ static ssize_t mts_attr_store_mfser_mode(struct device *dev,
 	return count;
 }
 
-/* accessory port 1 serial attributes */
-static DEVICE_ATTR_MTS(dev_attr_ap1_serial_mode, "serial-mode:0", mts_attr_show_mfser_mode, mts_attr_store_mfser_mode);
-static DEVICE_ATTR_MTS(dev_attr_ap1_rs4xx_term_res, "rs4xx-term-res:0", mts_attr_show_ap_mfser_pin, mts_attr_store_ap_mfser_pin);
-static DEVICE_ATTR_MTS(dev_attr_ap1_rts_override, "rts-override:0", mts_attr_show_ap_mfser_pin, mts_attr_store_ap_mfser_pin);
+// 1 serial mode
+// 1 rs4xx term resistor
+// 1 rts override
+static int ap_mfser_attrs_size = 3;
 
-static int ap1_mfser_attributes_size = 3;		// not including NULL at end
+static bool mfser_setup(enum ap port) {
+	struct kobj_attribute *attr;
+	char buf[32];
 
-static struct attribute *ap1_mfser_attributes[] = {
-	&dev_attr_ap1_serial_mode.attr,
-	&dev_attr_ap1_rs4xx_term_res.attr,		// gpio3
-	&dev_attr_ap1_rts_override.attr,		// gpio4
-	NULL,
-};
+	log_info("loading MFSER accessory card in port %d", port);
 
-/* accessory port 2 serial attributes */
-static DEVICE_ATTR_MTS(dev_attr_ap2_serial_mode, "serial-mode:1", mts_attr_show_mfser_mode, mts_attr_store_mfser_mode);
-static DEVICE_ATTR_MTS(dev_attr_ap2_rs4xx_term_res, "rs4xx-term-res:1", mts_attr_show_ap_mfser_pin, mts_attr_store_ap_mfser_pin);
-static DEVICE_ATTR_MTS(dev_attr_ap2_rts_override, "rts-override:1", mts_attr_show_ap_mfser_pin, mts_attr_store_ap_mfser_pin);
+	if (device_attrs_size + ap_mfser_attrs_size >= device_attrs_max_size) {
+		log_error("can't load MFSER accessory card in port %d - not enough room for attributes", port);
+		return false;
+	}
 
-static int ap2_mfser_attributes_size = 3;		// not including NULL at end
+	sprintf(buf, "serial-mode:%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_mfser_mode;
+	attr->store = mts_attr_store_mfser_mode;
+	device_attrs[device_attrs_size++] = &attr->attr;
 
-static struct attribute *ap2_mfser_attributes[] = {
-	&dev_attr_ap2_serial_mode.attr,
-	&dev_attr_ap2_rs4xx_term_res.attr,		// gpio3
-	&dev_attr_ap2_rts_override.attr,		// gpio4
-	NULL,
-};
+	sprintf(buf, "rs4xx-term-res:%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_mfser_pin;
+	attr->store = mts_attr_store_ap_mfser_pin;
+	device_attrs[device_attrs_size++] = &attr->attr;
 
+	sprintf(buf, "rts-override:%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_mfser_pin;
+	attr->store = mts_attr_store_ap_mfser_pin;
+	device_attrs[device_attrs_size++] = &attr->attr;
+
+	return true;
+}
 
+static bool mfser_teardown(enum ap port) {
+	log_info("unloading MFSER accessory card in port %d", port);
+	return true;
+}
+
+static struct ap_info mfser_info = {
+	.product_id = MTAC_MFSER_0_0,
+	.setup = &mfser_setup,
+	.teardown = &mfser_teardown
+};
diff --git a/io-module/mtr2d2.c b/io-module/mtr2d2.c
index 0926952..24a99f3 100644
--- a/io-module/mtr2d2.c
+++ b/io-module/mtr2d2.c
@@ -1,4 +1,3 @@
-
 static struct gpio_pin gpio_pins_mtr2d2_0_0[] = {
 	{
 		.name = "RADIO_RESET",
@@ -266,7 +265,8 @@ static struct gpio_pin gpio_pins_mtr2d2_0_0[] = {
 	{ },
 };
 
-static int mtr2d2_platform_attributes_size = 64;		// not including NULL at end
+static int mtr2d2_platform_attributes_max_size = 64;		// including NULL at end
+static int mtr2d2_platform_attributes_size = 21;
 
 static struct attribute *mtr2d2_platform_attributes[] = {
 	&dev_attr_vendor_id.attr,
@@ -295,6 +295,8 @@ static struct attribute *mtr2d2_platform_attributes[] = {
 	&dev_attr_board_temperature.attr,
 
 	/* extra space for the accessory card attributes */
+	NULL,	    // index 21
+	NULL,	    // index 22
 	NULL,	    // index 23
 	NULL,	    // index 24
 	NULL,	    // index 25
@@ -336,7 +338,6 @@ static struct attribute *mtr2d2_platform_attributes[] = {
 	NULL,	    // index 61
 	NULL,	    // index 62
 	NULL,	    // index 63
-	NULL,	    // index 64
 	NULL,
 };
 
diff --git a/io-module/mts_io.c b/io-module/mts_io.c
index 9adfd12..936d0d2 100644
--- a/io-module/mts_io.c
+++ b/io-module/mts_io.c
@@ -59,24 +59,33 @@
 extern uint8_t mts_id_eeprom[512];
 static struct mts_id_eeprom_layout id_eeprom;
 
-/* accessory card EEPROMs */
-#ifdef MTOCGD2
-extern uint8_t mts_ap1_eeprom[512];
-extern uint8_t mts_ap2_eeprom[512];
+// NUM_AP should be defined from the board code
+// it should be set to the value of CONFIG_MTS_NUM_ACCESSORY_PORTS
+// arch/arm/mach-at91/board-dt-sam9.c
+// if it is 0 or undefined, there is no accessory card support on this HW
+#ifdef CONFIG_MTS_NUM_ACCESSORY_PORTS
+
+#ifndef NUM_AP
+#define NUM_AP CONFIG_MTS_NUM_ACCESSORY_PORTS
+#endif
+
 #else
-uint8_t mts_ap1_eeprom[512] = {};
-uint8_t mts_ap2_eeprom[512] = {};
+#define NUM_AP 0
 #endif
-static struct mts_ap_eeprom_layout ap1_eeprom;
-static struct mts_ap_eeprom_layout ap2_eeprom;
 
-bool accessory_card_capable = false;
-bool have_accessory_card_slot_1 = false;
-bool have_accessory_card_slot_2 = false;
+#if NUM_AP > 0
+/* accessory card EEPROMs */
+extern uint8_t mts_ap_eeprom[NUM_AP][512];
+static struct mts_ap_eeprom_layout ap_eeprom[NUM_AP];
+#endif
+
+static struct ap_info* port_info[NUM_AP];
+
+static struct attribute **device_attrs;
+static size_t device_attrs_size;
+static size_t device_attrs_max_size;
 
 static uint8_t mts_product_id;
-static uint8_t mts_ap1_product_id;
-static uint8_t mts_ap2_product_id;
 static uint8_t has_spi_sout;
 static uint8_t has_spi_din;
 static uint8_t has_spi_dout;
@@ -98,6 +107,7 @@ static DEFINE_MUTEX(mts_io_mutex);
 #include "spi.c"
 
 /* accessory card support */
+#include "mtac.c"
 #include "mtac_gpiob.c"
 #include "mtac_mfser.c"