mcb: export bus information via sysfs

Export information about the bus stored in the FPGA's header to userspace via
sysfs, instead of hiding it in pr_debug()s from everyone.

Signed-off-by: Johannes Thumshirn <[e-mail]>
Reviewed-by: Andreas Werner <[e-mail]>
Tested-by: Andreas Werner <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

Documentation/ABI/testing/sysfs-bus-mcb

···
+What:		/sys/bus/mcb/devices/mcb:X
+Date:		March 2016
+KernelVersion:	4.7
+Contact:	Johannes Thumshirn <[e-mail]>
+Description:	Hardware chip or device hosting the MEN chameleon bus
+
+What:		/sys/bus/mcb/devices/mcb:X/revision
+Date:		March 2016
+KernelVersion:	4.7
+Contact:	Johannes Thumshirn <[e-mail]>
+Description:	The FPGA's revision number
+
+What:		/sys/bus/mcb/devices/mcb:X/minor
+Date:		March 2016
+KernelVersion:	4.7
+Contact:	Johannes Thumshirn <[e-mail]>
+Description:	The FPGA's minor number
+
+What:		/sys/bus/mcb/devices/mcb:X/model
+Date:		March 2016
+KernelVersion:	4.7
+Contact:	Johannes Thumshirn <[e-mail]>
+Description:	The FPGA's model number
+
+What:		/sys/bus/mcb/devices/mcb:X/name
+Date:		March 2016
+KernelVersion:	4.7
+Contact:	Johannes Thumshirn <[e-mail]>
+Description:	The FPGA's name

drivers/mcb/mcb-core.c

···
 		mdrv->shutdown(mdev);
 }
 
+static ssize_t revision_show(struct device *dev, struct device_attribute *attr,
+			 char *buf)
+{
+	struct mcb_bus *bus = to_mcb_bus(dev);
+
+	return scnprintf(buf, PAGE_SIZE, "%d\n", bus->revision);
+}
+static DEVICE_ATTR_RO(revision);
+
+static ssize_t model_show(struct device *dev, struct device_attribute *attr,
+			 char *buf)
+{
+	struct mcb_bus *bus = to_mcb_bus(dev);
+
+	return scnprintf(buf, PAGE_SIZE, "%c\n", bus->model);
+}
+static DEVICE_ATTR_RO(model);
+
+static ssize_t minor_show(struct device *dev, struct device_attribute *attr,
+			 char *buf)
+{
+	struct mcb_bus *bus = to_mcb_bus(dev);
+
+	return scnprintf(buf, PAGE_SIZE, "%d\n", bus->minor);
+}
+static DEVICE_ATTR_RO(minor);
+
+static ssize_t name_show(struct device *dev, struct device_attribute *attr,
+			 char *buf)
+{
+	struct mcb_bus *bus = to_mcb_bus(dev);
+
+	return scnprintf(buf, PAGE_SIZE, "%s\n", bus->name);
+}
+static DEVICE_ATTR_RO(name);
+
+static struct attribute *mcb_bus_attrs[] = {
+	&dev_attr_revision.attr,
+	&dev_attr_model.attr,
+	&dev_attr_minor.attr,
+	&dev_attr_name.attr,
+	NULL,
+};
+
+static const struct attribute_group mcb_carrier_group = {
+	.attrs = mcb_bus_attrs,
+};
+
+static const struct attribute_group *mcb_carrier_groups[] = {
+	&mcb_carrier_group,
+	NULL,
+};
+
+
 static struct bus_type mcb_bus_type = {
 	.name = "mcb",
 	.match = mcb_match,
···
 	.probe = mcb_probe,
 	.remove = mcb_remove,
 	.shutdown = mcb_shutdown,
+};
+
+static struct device_type mcb_carrier_device_type = {
+	.name = "mcb-carrier",
+	.groups = mcb_carrier_groups,
 };
 
 /**
···
 	device_initialize(&bus->dev);
 	bus->dev.parent = carrier;
 	bus->dev.bus = &mcb_bus_type;
+	bus->dev.type = &mcb_carrier_device_type;
 
 	dev_set_name(&bus->dev, "mcb:%d", bus_nr);
 	rc = device_add(&bus->dev);

drivers/mcb/mcb-internal.h

···
 
 #define PCI_VENDOR_ID_MEN		0x1a88
 #define PCI_DEVICE_ID_MEN_CHAMELEON	0x4d45
-#define CHAMELEON_FILENAME_LEN		12
 #define CHAMELEONV2_MAGIC		0xabce
 #define CHAM_HEADER_SIZE		0x200
 

drivers/mcb/mcb-parse.c

···
 	}
 	p += hsize;
 
-	pr_debug("header->revision = %d\n", header->revision);
-	pr_debug("header->model = 0x%x ('%c')\n", header->model,
-		header->model);
-	pr_debug("header->minor = %d\n", header->minor);
-	pr_debug("header->bus_type = 0x%x\n", header->bus_type);
-
-
-	pr_debug("header->magic = 0x%x\n", header->magic);
-	pr_debug("header->filename = \"%.*s\"\n", CHAMELEON_FILENAME_LEN,
-		header->filename);
+	bus->revision = header->revision;
+	bus->model = header->model;
+	bus->minor = header->minor;
+	snprintf(bus->name, CHAMELEON_FILENAME_LEN + 1, "%s",
+		 header->filename);
 
 	for_each_chameleon_cell(dtype, p) {
 		switch (dtype) {

include/linux/mcb.h

···
 #include <linux/device.h>
 #include <linux/irqreturn.h>
 
+#define CHAMELEON_FILENAME_LEN 12
+
 struct mcb_driver;
 struct mcb_device;
 
···
  * @carrier: pointer to carrier device
  * @bus_nr: mcb bus number
  * @get_irq: callback to get IRQ number
+ * @revision: the FPGA's revision number
+ * @model: the FPGA's model number
+ * @filename: the FPGA's name
  */
 struct mcb_bus {
 	struct device dev;
 	struct device *carrier;
 	int bus_nr;
+	u8 revision;
+	char model;
+	u8 minor;
+	char name[CHAMELEON_FILENAME_LEN + 1];
 	int (*get_irq)(struct mcb_device *dev);
 };
 #define to_mcb_bus(b) container_of((b), struct mcb_bus, dev)