Documentation/hwmon/max197.rst

   1 Kernel driver max197
   2 ====================
   3
   4 Author:
   5
   6   * Vivien Didelot <vivien.didelot@savoirfairelinux.com>
   7
   8 Supported chips:
   9
  10   * Maxim MAX197
  11
  12     Prefix: 'max197'
  13
  14     Datasheet: http://datasheets.maxim-ic.com/en/ds/MAX197.pdf
  15
  16   * Maxim MAX199
  17
  18     Prefix: 'max199'
  19
  20     Datasheet: http://datasheets.maxim-ic.com/en/ds/MAX199.pdf
  21
  22 Description
  23 -----------
  24
  25 The A/D converters MAX197, and MAX199 are both 8-Channel, Multi-Range, 5V,
  26 12-Bit DAS with 8+4 Bus Interface and Fault Protection.
  27
  28 The available ranges for the MAX197 are {0,-5V} to 5V, and {0,-10V} to 10V,
  29 while they are {0,-2V} to 2V, and {0,-4V} to 4V on the MAX199.
  30
  31 Platform data
  32 -------------
  33
  34 The MAX197 platform data (defined in linux/platform_data/max197.h) should be
  35 filled with a pointer to a conversion function, defined like::
  36
  37     int convert(u8 ctrl);
  38
  39 ctrl is the control byte to write to start a new conversion.
  40 On success, the function must return the 12-bit raw value read from the chip,
  41 or a negative error code otherwise.
  42
  43 Control byte format:
  44
  45 ======= ========== ============================================
  46 Bit     Name       Description
  47 7,6     PD1,PD0    Clock and Power-Down modes
  48 5       ACQMOD     Internal or External Controlled Acquisition
  49 4       RNG        Full-scale voltage magnitude at the input
  50 3       BIP        Unipolar or Bipolar conversion mode
  51 2,1,0   A2,A1,A0   Channel
  52 ======= ========== ============================================
  53
  54 Sysfs interface
  55 ---------------
  56
  57   ============== ==============================================================
  58   in[0-7]_input  The conversion value for the corresponding channel.
  59                  RO
  60
  61   in[0-7]_min    The lower limit (in mV) for the corresponding channel.
  62                  For the MAX197, it will be adjusted to -10000, -5000, or 0.
  63                  For the MAX199, it will be adjusted to -4000, -2000, or 0.
  64                  RW
  65
  66   in[0-7]_max    The higher limit (in mV) for the corresponding channel.
  67                  For the MAX197, it will be adjusted to 0, 5000, or 10000.
  68                  For the MAX199, it will be adjusted to 0, 2000, or 4000.
  69                  RW
  70   ============== ==============================================================