xref: /linux/Documentation/misc-devices/ics932s401.rst (revision 0898782247ae533d1f4e47a06bc5d4870931b284)
1*9b5db89eSMauro Carvalho Chehab========================
2*9b5db89eSMauro Carvalho ChehabKernel driver ics932s401
3*9b5db89eSMauro Carvalho Chehab========================
4*9b5db89eSMauro Carvalho Chehab
5*9b5db89eSMauro Carvalho ChehabSupported chips:
6*9b5db89eSMauro Carvalho Chehab
7*9b5db89eSMauro Carvalho Chehab  * IDT ICS932S401
8*9b5db89eSMauro Carvalho Chehab
9*9b5db89eSMauro Carvalho Chehab    Prefix: 'ics932s401'
10*9b5db89eSMauro Carvalho Chehab
11*9b5db89eSMauro Carvalho Chehab    Addresses scanned: I2C 0x69
12*9b5db89eSMauro Carvalho Chehab
13*9b5db89eSMauro Carvalho Chehab    Datasheet: Publicly available at the IDT website
14*9b5db89eSMauro Carvalho Chehab
15*9b5db89eSMauro Carvalho ChehabAuthor: Darrick J. Wong
16*9b5db89eSMauro Carvalho Chehab
17*9b5db89eSMauro Carvalho ChehabDescription
18*9b5db89eSMauro Carvalho Chehab-----------
19*9b5db89eSMauro Carvalho Chehab
20*9b5db89eSMauro Carvalho ChehabThis driver implements support for the IDT ICS932S401 chip family.
21*9b5db89eSMauro Carvalho Chehab
22*9b5db89eSMauro Carvalho ChehabThis chip has 4 clock outputs--a base clock for the CPU (which is likely
23*9b5db89eSMauro Carvalho Chehabmultiplied to get the real CPU clock), a system clock, a PCI clock, a USB
24*9b5db89eSMauro Carvalho Chehabclock, and a reference clock.  The driver reports selected and actual
25*9b5db89eSMauro Carvalho Chehabfrequency.  If spread spectrum mode is enabled, the driver also reports by what
26*9b5db89eSMauro Carvalho Chehabpercent the clock signal is being spread, which should be between 0 and -0.5%.
27*9b5db89eSMauro Carvalho ChehabAll frequencies are reported in KHz.
28*9b5db89eSMauro Carvalho Chehab
29*9b5db89eSMauro Carvalho ChehabThe ICS932S401 monitors all inputs continuously. The driver will not read
30*9b5db89eSMauro Carvalho Chehabthe registers more often than once every other second.
31*9b5db89eSMauro Carvalho Chehab
32*9b5db89eSMauro Carvalho ChehabSpecial Features
33*9b5db89eSMauro Carvalho Chehab----------------
34*9b5db89eSMauro Carvalho Chehab
35*9b5db89eSMauro Carvalho ChehabThe clocks could be reprogrammed to increase system speed.  I will not help you
36*9b5db89eSMauro Carvalho Chehabdo this, as you risk damaging your system!
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