drivers/hwmon/pmbus/ltc4286.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2
   3 #include <linux/err.h>
   4 #include <linux/i2c.h>
   5 #include <linux/init.h>
   6 #include <linux/kernel.h>
   7 #include <linux/module.h>
   8 #include <linux/pmbus.h>
   9 #include "pmbus.h"
  10
  11 /* LTC4286 register */
  12 #define LTC4286_MFR_CONFIG1     0xF2
  13
  14 /* LTC4286 configuration */
  15 #define VRANGE_SELECT_BIT       BIT(1)
  16
  17 #define LTC4286_MFR_ID_SIZE     3
  18
  19 /*
  20  * Initialize the MBR as default settings which is referred to LTC4286 datasheet
  21  * (March 22, 2022 version) table 3 page 16
  22  */
  23 static struct pmbus_driver_info ltc4286_info = {
  24         .pages = 1,
  25         .format[PSC_VOLTAGE_IN] = direct,
  26         .format[PSC_VOLTAGE_OUT] = direct,
  27         .format[PSC_CURRENT_OUT] = direct,
  28         .format[PSC_POWER] = direct,
  29         .format[PSC_TEMPERATURE] = direct,
  30         .m[PSC_VOLTAGE_IN] = 32,
  31         .b[PSC_VOLTAGE_IN] = 0,
  32         .R[PSC_VOLTAGE_IN] = 1,
  33         .m[PSC_VOLTAGE_OUT] = 32,
  34         .b[PSC_VOLTAGE_OUT] = 0,
  35         .R[PSC_VOLTAGE_OUT] = 1,
  36         .m[PSC_CURRENT_OUT] = 1024,
  37         .b[PSC_CURRENT_OUT] = 0,
  38         /*
  39          * The rsense value used in MBR formula in LTC4286 datasheet should be ohm unit.
  40          * However, the rsense value that user input is micro ohm.
  41          * Thus, the MBR setting which involves rsense should be shifted by 6 digits.
  42          */
  43         .R[PSC_CURRENT_OUT] = 3 - 6,
  44         .m[PSC_POWER] = 1,
  45         .b[PSC_POWER] = 0,
  46         /*
  47          * The rsense value used in MBR formula in LTC4286 datasheet should be ohm unit.
  48          * However, the rsense value that user input is micro ohm.
  49          * Thus, the MBR setting which involves rsense should be shifted by 6 digits.
  50          */
  51         .R[PSC_POWER] = 4 - 6,
  52         .m[PSC_TEMPERATURE] = 1,
  53         .b[PSC_TEMPERATURE] = 273,
  54         .R[PSC_TEMPERATURE] = 0,
  55         .func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_VOUT | PMBUS_HAVE_IOUT |
  56                    PMBUS_HAVE_PIN | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_VOUT |
  57                    PMBUS_HAVE_STATUS_IOUT | PMBUS_HAVE_STATUS_TEMP,
  58 };
  59
  60 static const struct i2c_device_id ltc4286_id[] = {
  61         { "ltc4286", },
  62         { "ltc4287", },
  63         {}
  64 };
  65 MODULE_DEVICE_TABLE(i2c, ltc4286_id);
  66
  67 static int ltc4286_probe(struct i2c_client *client)
  68 {
  69         int ret;
  70         const struct i2c_device_id *mid;
  71         u8 block_buffer[I2C_SMBUS_BLOCK_MAX + 1];
  72         struct pmbus_driver_info *info;
  73         u32 rsense;
  74         int vrange_nval, vrange_oval;
  75
  76         ret = i2c_smbus_read_block_data(client, PMBUS_MFR_ID, block_buffer);
  77         if (ret < 0) {
  78                 return dev_err_probe(&client->dev, ret,
  79                                      "Failed to read manufacturer id\n");
  80         }
  81
  82         /*
  83          * Refer to ltc4286 datasheet page 20
  84          * the manufacturer id is LTC
  85          */
  86         if (ret != LTC4286_MFR_ID_SIZE ||
  87             strncmp(block_buffer, "LTC", LTC4286_MFR_ID_SIZE)) {
  88                 return dev_err_probe(&client->dev, -ENODEV,
  89                                      "Manufacturer id mismatch\n");
  90         }
  91
  92         ret = i2c_smbus_read_block_data(client, PMBUS_MFR_MODEL, block_buffer);
  93         if (ret < 0) {
  94                 return dev_err_probe(&client->dev, ret,
  95                                      "Failed to read manufacturer model\n");
  96         }
  97
  98         for (mid = ltc4286_id; mid->name[0]; mid++) {
  99                 if (!strncasecmp(mid->name, block_buffer, strlen(mid->name)))
 100                         break;
 101         }
 102         if (!mid->name[0])
 103                 return dev_err_probe(&client->dev, -ENODEV,
 104                                      "Unsupported device\n");
 105
 106         if (of_property_read_u32(client->dev.of_node,
 107                                  "shunt-resistor-micro-ohms", &rsense))
 108                 rsense = 300; /* 0.3 mOhm if not set via DT */
 109
 110         if (rsense == 0)
 111                 return -EINVAL;
 112
 113         /* Check for the latter MBR value won't overflow */
 114         if (rsense > (INT_MAX / 1024))
 115                 return -EINVAL;
 116
 117         info = devm_kmemdup(&client->dev, &ltc4286_info, sizeof(*info),
 118                             GFP_KERNEL);
 119         if (!info)
 120                 return -ENOMEM;
 121
 122         /* Check MFR1 CONFIG register bit 1 VRANGE_SELECT before driver loading */
 123         vrange_oval = i2c_smbus_read_word_data(client, LTC4286_MFR_CONFIG1);
 124         if (vrange_oval < 0)
 125                 return dev_err_probe(&client->dev, vrange_oval,
 126                                      "Failed to read manufacturer configuration one\n");
 127         vrange_nval = vrange_oval;
 128
 129         if (device_property_read_bool(&client->dev, "adi,vrange-low-enable")) {
 130                 vrange_nval &=
 131                         ~VRANGE_SELECT_BIT; /* VRANGE_SELECT = 0, 25.6 volts */
 132
 133                 info->m[PSC_VOLTAGE_IN] = 128;
 134                 info->m[PSC_VOLTAGE_OUT] = 128;
 135                 info->m[PSC_POWER] = 4 * rsense;
 136         } else {
 137                 vrange_nval |=
 138                         VRANGE_SELECT_BIT; /* VRANGE_SELECT = 1, 102.4 volts */
 139
 140                 info->m[PSC_POWER] = rsense;
 141         }
 142         if (vrange_nval != vrange_oval) {
 143                 /* Set MFR1 CONFIG register bit 1 VRANGE_SELECT */
 144                 ret = i2c_smbus_write_word_data(client, LTC4286_MFR_CONFIG1,
 145                                                 vrange_nval);
 146                 if (ret < 0)
 147                         return dev_err_probe(&client->dev, ret,
 148                                              "Failed to set vrange\n");
 149         }
 150
 151         info->m[PSC_CURRENT_OUT] = 1024 * rsense;
 152
 153         return pmbus_do_probe(client, info);
 154 }
 155
 156 static const struct of_device_id ltc4286_of_match[] = {
 157         { .compatible = "lltc,ltc4286" },
 158         { .compatible = "lltc,ltc4287" },
 159         {}
 160 };
 161
 162 static struct i2c_driver ltc4286_driver = {
 163         .driver = {
 164                 .name = "ltc4286",
 165                 .of_match_table = ltc4286_of_match,
 166         },
 167         .probe = ltc4286_probe,
 168         .id_table = ltc4286_id,
 169 };
 170
 171 module_i2c_driver(ltc4286_driver);
 172
 173 MODULE_AUTHOR("Delphine CC Chiu <[email protected]>");
 174 MODULE_DESCRIPTION("PMBUS driver for LTC4286 and compatibles");
 175 MODULE_LICENSE("GPL");