[linux-block.git] / Documentation / misc-devices / ics932s401.rst

========================
Kernel driver ics932s401
========================

Supported chips:

  * IDT ICS932S401

    Prefix: 'ics932s401'

    Addresses scanned: I2C 0x69

    Datasheet: Publicly available at the IDT website

Author: Darrick J. Wong

Description
-----------

This driver implements support for the IDT ICS932S401 chip family.

This chip has 4 clock outputs--a base clock for the CPU (which is likely
multiplied to get the real CPU clock), a system clock, a PCI clock, a USB
clock, and a reference clock.  The driver reports selected and actual
frequency.  If spread spectrum mode is enabled, the driver also reports by what
percent the clock signal is being spread, which should be between 0 and -0.5%.
All frequencies are reported in KHz.

The ICS932S401 monitors all inputs continuously. The driver will not read
the registers more often than once every other second.

Special Features
----------------

The clocks could be reprogrammed to increase system speed.  I will not help you
do this, as you risk damaging your system!
Commit	Line	Data
9b5db89e	1	========================
a412ae3f	2	Kernel driver ics932s401
9b5db89e	3	========================
a412ae3f DW	4
a412ae3f DW	5	Supported chips:
9b5db89e	6
a412ae3f	7	* IDT ICS932S401
9b5db89e	8
a412ae3f	9	Prefix: 'ics932s401'
9b5db89e	10
a412ae3f	11	Addresses scanned: I2C 0x69
9b5db89e	12
25985edc	13	Datasheet: Publicly available at the IDT website
a412ae3f DW	14
	15	Author: Darrick J. Wong
	16
	17	Description
	18	-----------
	19
	20	This driver implements support for the IDT ICS932S401 chip family.
	21
	22	This chip has 4 clock outputs--a base clock for the CPU (which is likely
	23	multiplied to get the real CPU clock), a system clock, a PCI clock, a USB
	24	clock, and a reference clock. The driver reports selected and actual
	25	frequency. If spread spectrum mode is enabled, the driver also reports by what
	26	percent the clock signal is being spread, which should be between 0 and -0.5%.
	27	All frequencies are reported in KHz.
	28
	29	The ICS932S401 monitors all inputs continuously. The driver will not read
	30	the registers more often than once every other second.
	31
	32	Special Features
	33	----------------
	34
	35	The clocks could be reprogrammed to increase system speed. I will not help you
	36	do this, as you risk damaging your system!