[RFC PATCH 0/3] gpio: ep93xx: convert to multi irqchips

[Nikita Shubin <nikita.shubin@xxxxxxxxxxx>]

I was lucky enough to became an owner of some splendid piece's of
antiques called ts7250 based on the top of Cirrus Logic EP9302.

I don't know what fate expects this hardware (it's not EOL it's just Not
recommended for new designs) but i wanted to share fixes in ep93xx gpio area.

It seems ep93xx is deadly broken at current state usage of AB gpiochips
interrupts leads to deadlocks coused by irq_unmask/irq_mask recursions.

Port F is not working at all:

-bash-5.0# gpio-event-mon -n gpiochip5 -o 0 -r -f
------------[ cut here ]------------
kernel BUG at drivers/gpio/gpio-ep93xx.c:64!
Internal error: Oops - BUG: 0 [#1] ARM
Modules linked in:
CPU: 0 PID: 403 Comm: gpio-event-mon Not tainted 5.9.10-00011-ge93e9618628b-dirty #19
Hardware name: Technologic Systems TS-72xx SBC
PC is at ep93xx_gpio_update_int_params+0x1c/0x80
LR is at ep93xx_gpio_update_int_params+0x14/0x80
pc : [<c03abc44>]    lr : [<c03abc3c>]    psr: 20000093
sp : c158de00  ip : 00000000  fp : 00000001
r10: c44154d4  r9 : 00000000  r8 : c4415020
r7 : c04ef884  r6 : c051c842  r5 : c4415020  r4 : 00000005
r3 : 00000000  r2 : 00000000  r1 : c04eb768  r0 : 00000008
Flags: nzCv  IRQs off  FIQs on  Mode SVC_32  ISA ARM  Segment none
Control: 0000717f  Table: 01684000  DAC: 00000051
Process gpio-event-mon (pid: 403, stack limit = 0x(ptrval))
Stack: (0xc158de00 to 0xc158e000)
de00: 00000005 00000002 c051c842 c0238dc0 c0238c98 c0238c98 c04ef874 00000000
de20: 00000003 c04fcfcc 60000013 c04ef910 c04ef8d4 c00456f0 c04ef874 c15f1e00
de40: 00000000 00000000 00000001 c0045d40 c15f1e00 c4400160 c0044ca8 c04ef8a8
de60: 60000013 00000000 c15f1e00 c04ef874 c04ef884 00000001 c0235d70 c158b800
de80: be825f0f c0045ec8 00000003 c158b800 c440aa00 be825bc8 00000003 00000001
dea0: 00000000 c0236f00 c44ed3a0 c158b800 c45c2015 00000000 00000001 00000003
dec0: 6f697067 6576652d 6d2d746e 00006e6f 00000000 00000000 00000000 00000000
dee0: be825df4 c00abb0c c440c500 c00aabd4 c440c500 c528b840 c45c2010 c04e1228
df00: 00000ff0 c4478d28 c030b404 be825bc8 c1550e20 00000003 c1550e20 c00c3388
df20: c4478d28 c00c3d48 be825f0f c00abd00 c45c2000 c45c2000 c1550e20 c00bfea8
df40: 00000003 c00b0714 00000000 c4450000 00000004 00000100 00000001 c04e1228
df60: c158dfb0 ffffff9c 000231f8 00000003 00000142 c00b085c 00000000 c04e1228
df80: 00000000 be825f0f 00000003 00000003 00000036 c00083c4 c158c000 00000000
dfa0: be825f0f c00081e0 be825f0f 00000003 00000003 c030b404 be825bc8 00000000
dfc0: be825f0f 00000003 00000003 00000036 00000001 00000000 00022070 be825f0f
dfe0: b6f2e4e0 be825bac 00010acc b6f2e4ec 60000010 00000003 00000000 00000000
[<c03abc44>] (ep93xx_gpio_update_int_params) from [<c0238dc0>] (ep93xx_gpio_irq_type+0x128/0x1c0)
[<c0238dc0>] (ep93xx_gpio_irq_type) from [<c00456f0>] (__irq_set_trigger+0x6c/0x128)
[<c00456f0>] (__irq_set_trigger) from [<c0045d40>] (__setup_irq+0x594/0x678)
[<c0045d40>] (__setup_irq) from [<c0045ec8>] (request_threaded_irq+0xa4/0x128)
[<c0045ec8>] (request_threaded_irq) from [<c0236f00>] (gpio_ioctl+0x300/0x4d8)
[<c0236f00>] (gpio_ioctl) from [<c00c3388>] (vfs_ioctl+0x24/0x3c)
[<c00c3388>] (vfs_ioctl) from [<c00c3d48>] (sys_ioctl+0xbc/0x768)
[<c00c3d48>] (sys_ioctl) from [<c00081e0>] (ret_fast_syscall+0x0/0x50)
Exception stack(0xc158dfa8 to 0xc158dff0)
dfa0:                   be825f0f 00000003 00000003 c030b404 be825bc8 00000000
dfc0: be825f0f 00000003 00000003 00000036 00000001 00000000 00022070 be825f0f
dfe0: b6f2e4e0 be825bac 00010acc b6f2e4ec
Code: e59f0060 ebfff3e1 e3540002 9a000000 (e7f001f2)
---[ end trace 3f6544e133e9f5ae ]---

These change requires your judgment.