Messages in this thread | | | Date | Tue, 25 Jul 2023 13:51:37 -0700 | Subject | Re: [PATCH] Documentation: devices.txt: reconcile serial/ucc_uart minor numers | From | Randy Dunlap <> |
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On 7/25/23 13:38, Timur Tabi wrote: > On Mon, Jul 24, 2023 at 1:33 AM Randy Dunlap <rdunlap@infradead.org> wrote: >> >> Reconcile devices.txt with serial/ucc_uart.c regarding device number >> assignments. ucc_uart.c supports 4 ports and uses minor devnums >> 46-49, so update devices.txt with that info. >> Then update ucc_uart.c's reference to the location of the devices.txt >> list in the kernel source tree. >> >> Fixes: d7584ed2b994 ("[POWERPC] qe-uart: add support for Freescale QUICCEngine UART") >> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") >> Signed-off-by: Randy Dunlap <rdunlap@infradead.org> >> Cc: Timur Tabi <timur@kernel.org> >> Cc: Kumar Gala <galak@kernel.crashing.org> >> Cc: linuxppc-dev@lists.ozlabs.org >> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> >> Cc: Jiri Slaby <jirislaby@kernel.org> >> Cc: linux-serial@vger.kernel.org >> Cc: Jonathan Corbet <corbet@lwn.net> >> Cc: linux-doc@vger.kernel.org > > Acked-by: Timur Tabi <timur@kernel.org> > > One thing does concern me. The UCC UART driver piggy-backs on the CPM > driver's layout (see cpm_uart.h), but apparently CPM UART supports 6 > devices, not four: > > #define UART_NR fs_uart_nr > > where fs_uart_nr is defined in enum fs_uart_id. > > Unfortunately, it's been so long since I've touched this code, I'm not > sure whether this means anything.
If CPM UART code ever worked with > 4 ports, it probably just used minor devnums that were not allocated to it.
Also, it looks like the CPU UART part of Documentation/admin-guide/devices.txt needs to be updated:
46 = /dev/cucpm0 Callout device for ttyCPM0 ... 49 = /dev/cucpm5 Callout device for ttyCPM5
The driver must use some tricks to get 6 ports into 4 devnums. :)
-- ~Randy
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