swh:1:snp:173f8deb0c56c557784b4fd217e7608ac6197844
Tip revision: b9bbe6ed63b2b9f2c9ee5cbd0f2c946a2723f4ce authored by Linus Torvalds on 17 May 2020, 23:48:37 UTC
Linux 5.7-rc6
Linux 5.7-rc6
Tip revision: b9bbe6e
max197.rst
Kernel driver max197
====================
Author:
* Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Supported chips:
* Maxim MAX197
Prefix: 'max197'
Datasheet: http://datasheets.maxim-ic.com/en/ds/MAX197.pdf
* Maxim MAX199
Prefix: 'max199'
Datasheet: http://datasheets.maxim-ic.com/en/ds/MAX199.pdf
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
============== ==============================================================