target/linux/generic/backport-5.10/872-v5.13-02-hwmon-tps23861-set-current-shunt-value.patch

   1 From 9bca598d4a86e88afb29fdb516c68b2519bd0fb9 Mon Sep 17 00:00:00 2001
   2 From: Robert Marko <robert.marko@sartura.hr>
   3 Date: Thu, 10 Jun 2021 00:07:27 +0200
   4 Subject: [PATCH 3/4] hwmon: (tps23861) set current shunt value
   5
   6 TPS23861 has a configuration bit for setting of the
   7 current shunt value used on the board.
   8 Its bit 0 of the General Mask 1 register.
   9
  10 According to the datasheet bit values are:
  11 0 for 255 mOhm (Default)
  12 1 for 250 mOhm
  13
  14 So, configure the bit before registering the hwmon
  15 device according to the value passed in the DTS or
  16 default one if none is passed.
  17
  18 This caused potentially reading slightly skewed values
  19 due to max current value being 1.02A when 250mOhm shunt
  20 is used instead of 1.0A when 255mOhm is used.
  21
  22 Fixes: fff7b8ab2255 ("hwmon: add Texas Instruments TPS23861 driver")
  23 Signed-off-by: Robert Marko <robert.marko@sartura.hr>
  24 Link: https://lore.kernel.org/r/20210609220728.499879-2-robert.marko@sartura.hr
  25 Signed-off-by: Guenter Roeck <linux@roeck-us.net>
  26 ---
  27  drivers/hwmon/tps23861.c | 12 ++++++++++++
  28  1 file changed, 12 insertions(+)
  29
  30 --- a/drivers/hwmon/tps23861.c
  31 +++ b/drivers/hwmon/tps23861.c
  32 @@ -99,6 +99,9 @@
  33  #define POWER_ENABLE                   0x19
  34  #define TPS23861_NUM_PORTS             4
  35
  36 +#define TPS23861_GENERAL_MASK_1                0x17
  37 +#define TPS23861_CURRENT_SHUNT_MASK    BIT(0)
  38 +
  39  #define TEMPERATURE_LSB                        652 /* 0.652 degrees Celsius */
  40  #define VOLTAGE_LSB                    3662 /* 3.662 mV */
  41  #define SHUNT_RESISTOR_DEFAULT         255000 /* 255 mOhm */
  42 @@ -561,6 +564,15 @@ static int tps23861_probe(struct i2c_cli
  43         else
  44                 data->shunt_resistor = SHUNT_RESISTOR_DEFAULT;
  45
  46 +       if (data->shunt_resistor == SHUNT_RESISTOR_DEFAULT)
  47 +               regmap_clear_bits(data->regmap,
  48 +                                 TPS23861_GENERAL_MASK_1,
  49 +                                 TPS23861_CURRENT_SHUNT_MASK);
  50 +       else
  51 +               regmap_set_bits(data->regmap,
  52 +                               TPS23861_GENERAL_MASK_1,
  53 +                               TPS23861_CURRENT_SHUNT_MASK);
  54 +
  55         hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
  56                                                          data, &tps23861_chip_info,
  57                                                          NULL);