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1// SPDX-License-Identifier: GPL-2.0-or-later2 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 0xF213 14/* LTC4286 configuration */15#define VRANGE_SELECT_BIT BIT(1)16 17#define LTC4286_MFR_ID_SIZE 318 19/*20 * Initialize the MBR as default settings which is referred to LTC4286 datasheet21 * (March 22, 2022 version) table 3 page 1622 */23static 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 60static const struct i2c_device_id ltc4286_id[] = {61 { "ltc4286", },62 { "ltc4287", },63 {}64};65MODULE_DEVICE_TABLE(i2c, ltc4286_id);66 67static 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 2084 * the manufacturer id is LTC85 */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, <c4286_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 156static const struct of_device_id ltc4286_of_match[] = {157 { .compatible = "lltc,ltc4286" },158 { .compatible = "lltc,ltc4287" },159 {}160};161 162static 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 171module_i2c_driver(ltc4286_driver);172 173MODULE_AUTHOR("Delphine CC Chiu <Delphine_CC_Chiu@wiwynn.com>");174MODULE_DESCRIPTION("PMBUS driver for LTC4286 and compatibles");175MODULE_LICENSE("GPL");176