Add kernel driver for the power board

Author: MartijnBraam

hardware/drivers/power_board/.gitignore

@@ -0,0 +1,7 @@
+*.ko
+*.o
+*.cmd
+*.mod
+*.mod.c
+/modules.order
+/Module.symvers

hardware/drivers/power_board/Makefile

@@ -0,0 +1,7 @@
+obj-m += power_board.o
+
+all:
+	make -C /lib/modules/$(shell uname -r)/build M=$(PWD) modules
+
+clean:
+	make -C /lib/modules/$(shell uname -r)/build M=$(PWD) clean

hardware/drivers/power_board/power_board.c

@@ -0,0 +1,330 @@
+#include<linux/module.h>
+#include<linux/init.h>
+#include<linux/usb.h>
+#include<linux/hwmon.h>
+#include<linux/errno.h>
+
+#define FOSDEM_VENDOR_ID 0xF05D
+#define FOSDEM_PRODUCT_KRAB 0x4011
+
+static struct usb_device_id power_board_table [] = {
+	{ USB_DEVICE(FOSDEM_VENDOR_ID, FOSDEM_PRODUCT_KRAB) }, /* Krab Controller */
+	{ } /* Terminating entry */
+};
+
+MODULE_DEVICE_TABLE(usb, power_board_table);
+
+#define POWER_BOARD_MINOR_BASE 0
+
+#define VENDOR_REQUEST_TEMPERATURE 0x10
+
+struct power_board {
+	struct usb_device * udev;
+	__u8 bulk_in_addr;
+	__u8 bulk_out_addr;
+
+	char *read_buffer;
+	size_t read_buffer_len;
+	char *write_buffer;
+	size_t write_buffer_len;
+
+	int protocol;
+	int present;
+	struct kref kref;
+};
+#define to_pb(d) container_of(d, struct power_board, kref)
+
+static struct usb_driver power_board_driver;
+
+static int vendor_command(struct usb_device *dev, unsigned char request, unsigned char value, unsigned char index, void *buf, int size)
+{
+	return usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
+			request,
+			USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_OTHER,
+			value,
+			index, buf, size,
+			USB_CTRL_GET_TIMEOUT);
+}
+
+static void power_board_delete(struct kref *kref)
+{
+	printk("PB DELETE!\n");
+	struct power_board *dev = to_pb(kref);
+	usb_put_dev(dev->udev);
+	kfree(dev);
+}
+
+static int power_board_open(struct inode *inode, struct file *file)
+{
+	struct power_board *dev;
+	struct usb_interface *interface;
+	int result;
+
+	interface = usb_find_interface(&power_board_driver, iminor(inode));
+	if (!interface)
+		return -ENODEV;
+
+	dev = usb_get_intfdata(interface);
+	if (!dev)
+		return -ENODEV;
+
+	kref_get(&dev->kref);
+	file->private_data = dev;
+
+	return result;
+}
+
+static int power_board_release(struct inode *inode, struct file *file)
+{
+	struct power_board *dev;
+	dev = file->private_data;
+	if (dev == NULL)
+		return -ENODEV;
+
+	kref_put(&dev->kref, power_board_delete);
+	return 0;
+}
+
+static ssize_t power_board_read(struct file *file, char *buffer, size_t count,
+			 loff_t *ppos)
+{
+	struct power_board *dev = file->private_data;
+	int result;
+
+	if(!dev->present)
+		return -ENODEV;
+
+	//result = simple_read_from_buffer(buffer, count, ppos, 
+	result = 0;
+	return result;
+}
+
+static ssize_t power_board_write(struct file *file, const char *user_buffer,
+			  size_t count, loff_t *ppos)
+{
+	struct power_board *dev = file->private_data;
+	int result;
+
+	char *buf = NULL;
+	size_t writesize = min_t(size_t, count, PAGE_SIZE - 512);
+
+	// Zero byte write is a noop
+	if (count == 0)
+		return 0;
+
+	//result = usb_bulk_msg(dev->udev, usb_sndbulkpipe(dev->udev, dev->bulk_out_addr), dev->bu);
+
+	return 0;
+}
+
+static const struct file_operations power_board_fops = {
+	.owner = THIS_MODULE,
+	.read = power_board_read,
+	.write = power_board_write,
+	.open = power_board_open,
+	.release = power_board_release,
+};
+
+/*********************************
+ * Board API
+ ********************************/
+
+long power_board_get_temperature(struct power_board *pb) {
+	int retval;
+	int temp;
+	uint8_t *buffer = kmalloc(2, GFP_KERNEL);
+	if (!buffer)
+		return 0;
+
+	retval = vendor_command(pb->udev, VENDOR_REQUEST_TEMPERATURE, 0, 0, buffer, 2);
+	if (retval)
+		dev_info(&pb->udev->dev, "retval = %d\n", retval);
+
+	temp = buffer[0] << 8 | buffer[1];
+	long celcius = ((temp >> (16-12)) * 1000) >> (12-8);
+	kfree(buffer);
+	return celcius;
+}
+
+/*********************************
+ * HWMON Integration
+ ********************************/
+
+static int power_board_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
+		u32 attr, int channel, long *val)
+{
+	struct power_board *data = dev_get_drvdata(dev);
+
+	switch(type) {
+	case hwmon_temp:
+		switch(attr) {
+		case hwmon_temp_input:
+			*val = power_board_get_temperature(data);
+			return 0;
+		}
+	}
+	return -EINVAL;
+}
+
+static int power_board_hwmon_write(struct device *dev, enum hwmon_sensor_types type,
+		u32 attr, int channel, long val)
+{
+	return 0;
+}
+
+static umode_t power_board_hwmon_is_visible(const void *data, enum hwmon_sensor_types type,
+		u32 attr, int channel)
+{
+	const struct power_board *config_data = data;
+
+	switch (type) {
+	case hwmon_temp:
+		switch (attr) {
+		case hwmon_temp_input:
+			return 0444;
+		}
+	}
+	return 0;
+}
+
+static const struct hwmon_channel_info * const power_board_hwmon_info[] = {
+	HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT),
+	NULL
+};
+
+static const struct hwmon_ops power_board_hwmon_ops = {
+	.is_visible = power_board_hwmon_is_visible,
+	.read = power_board_hwmon_read,
+	.write = power_board_hwmon_write,
+};
+
+static const struct hwmon_chip_info power_board_chip_info = {
+	.ops = &power_board_hwmon_ops,
+	.info = power_board_hwmon_info,
+};
+
+/*********************************
+ * SYSFS Integration
+ ********************************/
+
+static ssize_t temperature_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct usb_interface *intf = to_usb_interface(dev);
+	struct power_board *pb = usb_get_intfdata(intf);
+
+	long celcius = power_board_get_temperature(pb);
+	return sprintf(buf, "%ld", celcius);
+}
+static DEVICE_ATTR_RO(temperature);
+
+static struct attribute *power_board_attrs[] = {
+	&dev_attr_temperature.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(power_board);
+
+static struct usb_class_driver power_board_class = {
+	.name = "powerboard%d",
+	.fops = &power_board_fops,
+	.minor_base = POWER_BOARD_MINOR_BASE,
+};
+
+static int power_board_probe(struct usb_interface *interface,
+		const struct usb_device_id *id)
+{
+	int result;
+	int protocol;
+	struct power_board *dev;
+	struct device *parent;
+	struct usb_host_interface *iface_desc;
+	struct usb_endpoint_descriptor *endpoint_in;
+	struct usb_endpoint_descriptor *endpoint_out;
+	int in_end_size;
+	int out_end_size;
+
+	parent = &interface->dev;
+	iface_desc = interface->cur_altsetting;
+
+	if (iface_desc->desc.bInterfaceClass != 0xFF)
+		return -ENODEV;
+
+	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+	if(!dev)
+		return -ENOMEM;
+
+	kref_init(&dev->kref);
+
+	dev->udev = usb_get_dev(interface_to_usbdev(interface));
+
+	// Get the bulk-in and bulk-out endpoint
+	result = usb_find_common_endpoints(iface_desc, &endpoint_in, &endpoint_out, NULL, NULL);
+	if (result) {
+		dev_err(&interface->dev, "Unable to find the bulk endpoints\n");
+		goto error;
+	}
+	dev->bulk_in_addr = endpoint_in->bEndpointAddress;
+	dev->bulk_out_addr = endpoint_out->bEndpointAddress;
+	dev->protocol = protocol;
+	dev->present = 1;
+
+	dev->read_buffer_len = usb_endpoint_maxp(endpoint_in) * 10;
+	dev->write_buffer_len = usb_endpoint_maxp(endpoint_in) * 10;
+	dev->read_buffer = kmalloc(dev->read_buffer_len, GFP_KERNEL);
+	if (!dev->read_buffer) {
+		result = -ENOMEM;
+		goto error;
+	}
+	dev->write_buffer = kmalloc(dev->write_buffer_len, GFP_KERNEL);
+	if (!dev->write_buffer) {
+		result = -ENOMEM;
+		goto error;
+	}
+
+	usb_set_intfdata(interface, dev);
+
+	result = usb_register_dev(interface, &power_board_class);
+	if (result) {
+		dev_err(&interface->dev, "Unable to allocate minor number.\n");
+		usb_set_intfdata(interface, NULL);
+		goto error;
+	}
+
+	// Register with the HWMON subsystem
+	devm_hwmon_device_register_with_info(parent, "PowerBoard", dev, &power_board_chip_info, NULL);
+
+	dev_info(&interface->dev, "Loaded FOSDEM power board driver\n");
+	return 0;
+
+error:
+	kref_put(&dev->kref, power_board_delete);
+	return result;
+
+}
+
+static void power_board_disconnect(struct usb_interface *interface)
+{
+	struct power_board *dev;
+
+	dev = usb_get_intfdata(interface);
+	dev->present = 0;
+	usb_deregister_dev(interface, &power_board_class);
+
+	usb_set_intfdata(interface, NULL);
+	usb_put_dev(dev->udev);
+	kref_put(&dev->kref, power_board_delete);
+}
+
+static struct usb_driver power_board_driver = {
+	.name = "power_board",
+	.probe = power_board_probe,
+	.disconnect = power_board_disconnect,
+	.id_table = power_board_table,
+	.dev_groups = power_board_groups,
+};
+
+module_usb_driver(power_board_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Martijn Braam");
+MODULE_DESCRIPTION("Kernel driver for the FOSDEM power board");
+MODULE_VERSION("0.1");