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linux-yocto/Documentation/hwmon/max197
Vivien Didelot 6c1fe725fd hwmon: add Maxim MAX197 support 
The MAX197 is an A/D converter, made by Maxim. This driver currently
supports the MAX197, and MAX199. They are both 8-Channel, Multi-Range,
5V, 12-Bit DAS with 8+4 Bus Interface and Fault Protection.

The available ranges for the MAX197 are {0,-5V} to 5V, and {0,-10V} to
10V, while they are {0,-2V} to 2V, and {0,-4V} to 4V on the MAX199.

Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2012-09-23 21:08:33 -07:00

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Maxim MAX197 driver

Author:

Supported chips:

Description

The A/D converters MAX197, and MAX199 are both 8-Channel, Multi-Range, 5V, 12-Bit DAS with 8+4 Bus Interface and Fault Protection.

The available ranges for the MAX197 are {0,-5V} to 5V, and {0,-10V} to 10V, while they are {0,-2V} to 2V, and {0,-4V} to 4V on the MAX199.

Platform data

The MAX197 platform data (defined in linux/platform_data/max197.h) should be filled with a pointer to a conversion function, defined like:

int convert(u8 ctrl);

ctrl is the control byte to write to start a new conversion. On success, the function must return the 12-bit raw value read from the chip, or a negative error code otherwise.

Control byte format:

Bit Name Description 7,6 PD1,PD0 Clock and Power-Down modes 5 ACQMOD Internal or External Controlled Acquisition 4 RNG Full-scale voltage magnitude at the input 3 BIP Unipolar or Bipolar conversion mode 2,1,0 A2,A1,A0 Channel

Sysfs interface

  • in[0-7]_input: The conversion value for the corresponding channel. RO

  • in[0-7]_min: The lower limit (in mV) for the corresponding channel. For the MAX197, it will be adjusted to -10000, -5000, or 0. For the MAX199, it will be adjusted to -4000, -2000, or 0. RW

  • in[0-7]_max: The higher limit (in mV) for the corresponding channel. For the MAX197, it will be adjusted to 0, 5000, or 10000. For the MAX199, it will be adjusted to 0, 2000, or 4000. RW