fsi: Add new central chardev support

The various FSI devices (sbefifo, occ, scom, more to come)
currently use misc devices.

This is problematic as the minor device space for misc is
limited and there can be a lot of them. Also it limits our
ability to move them to a dedicated /dev/fsi directory or
to be smart about device naming and numbering.

It also means we have IDAs on every single of these drivers

This creates a common fsi "device_type" for the optional
/dev/fsi grouping and a dev_t allocator for all FSI devices.

"Legacy" devices get to use a backward compatible numbering
scheme (as long as chip id <16 and there's only one copy
of a given unit type per chip).

A single major number and a single IDA are shared for all
FSI devices.

This doesn't convert the FSI device drivers to use the new
scheme yet, they will be converted individually.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 11 insertions, 1 deletions

diff --git a/include/linux/fsi.h b/include/linux/fsi.h
index 141fd38d061f..ec3be0d5b786 100644
--- a/include/linux/fsi.h
+++ b/include/linux/fsi.h
@@ -76,8 +76,18 @@ extern int fsi_slave_read(struct fsi_slave *slave, uint32_t addr,
 extern int fsi_slave_write(struct fsi_slave *slave, uint32_t addr,
 		const void *val, size_t size);
 
+extern struct bus_type fsi_bus_type;
+extern const struct device_type fsi_cdev_type;
 
+enum fsi_dev_type {
+	fsi_dev_cfam,
+	fsi_dev_sbefifo,
+	fsi_dev_scom,
+	fsi_dev_occ
+};
 
-extern struct bus_type fsi_bus_type;
+extern int fsi_get_new_minor(struct fsi_device *fdev, enum fsi_dev_type type,
+			     dev_t *out_dev, int *out_index);
+extern void fsi_free_minor(dev_t dev);
 
 #endif /* LINUX_FSI_H */