1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Hardware monitoring driver for Analog Devices MAX20830 4 * 5 * Copyright (C) 2026 Analog Devices, Inc. 6 */ 7 8 #include <linux/errno.h> 9 #include <linux/i2c.h> 10 #include <linux/mod_devicetable.h> 11 #include <linux/module.h> 12 #include <linux/string.h> 13 #include "pmbus.h" 14 15 #define MAX20830_IC_DEVICE_ID_LENGTH 9 16 17 static struct pmbus_driver_info max20830_info = { 18 .pages = 1, 19 .format[PSC_VOLTAGE_IN] = linear, 20 .format[PSC_VOLTAGE_OUT] = linear, 21 .format[PSC_CURRENT_OUT] = linear, 22 .format[PSC_TEMPERATURE] = linear, 23 .func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_VOUT | PMBUS_HAVE_IOUT | 24 PMBUS_HAVE_TEMP | 25 PMBUS_HAVE_STATUS_VOUT | PMBUS_HAVE_STATUS_IOUT | 26 PMBUS_HAVE_STATUS_INPUT | PMBUS_HAVE_STATUS_TEMP, 27 }; 28 29 static int max20830_probe(struct i2c_client *client) 30 { 31 u8 buf[I2C_SMBUS_BLOCK_MAX + 1] = {}; 32 int ret; 33 34 if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_BLOCK_DATA) && 35 !i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_I2C_BLOCK)) 36 return -ENODEV; 37 38 /* 39 * Use i2c_smbus_read_block_data() if supported, otherwise fall back 40 * to i2c_smbus_read_i2c_block_data() to support I2C controllers 41 * which do not support SMBus block reads. 42 */ 43 if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_BLOCK_DATA)) { 44 /* Reads 9 Data bytes from MAX20830 */ 45 ret = i2c_smbus_read_block_data(client, PMBUS_IC_DEVICE_ID, buf); 46 if (ret < 0) 47 return dev_err_probe(&client->dev, ret, 48 "Failed to read IC_DEVICE_ID\n"); 49 } else { 50 /* Reads 1 length byte + 9 Data bytes from MAX20830 */ 51 ret = i2c_smbus_read_i2c_block_data(client, PMBUS_IC_DEVICE_ID, 52 MAX20830_IC_DEVICE_ID_LENGTH + 1, 53 buf); 54 if (ret < 0) 55 return dev_err_probe(&client->dev, ret, 56 "Failed to read IC_DEVICE_ID\n"); 57 /* 58 * Moves data forward, removing the length byte, this is to 59 * match the format of i2c_smbus_read_block_data(). 60 * Also adjust return value to reflect length byte removal. 61 */ 62 memmove(buf, buf + 1, MAX20830_IC_DEVICE_ID_LENGTH); 63 ret = ret - 1; 64 } 65 66 /* 67 * MAX20830 IC_DEVICE_ID sends string data "MAX20830\0". 68 * Return value should at least be 9 bytes of data. 69 */ 70 if (ret < MAX20830_IC_DEVICE_ID_LENGTH) 71 return dev_err_probe(&client->dev, -ENODEV, 72 "IC_DEVICE_ID too short: expected at least 9 bytes, got %d\n", 73 ret); 74 75 /* 9 bytes of data, buf[0]-buf[7] = "MAX20830", buf[8] = '\0' */ 76 buf[MAX20830_IC_DEVICE_ID_LENGTH - 1] = '\0'; 77 if (strncmp(buf, "MAX20830", MAX20830_IC_DEVICE_ID_LENGTH - 1)) 78 return dev_err_probe(&client->dev, -ENODEV, 79 "Unsupported device: '%s'\n", buf); 80 81 return pmbus_do_probe(client, &max20830_info); 82 } 83 84 static const struct i2c_device_id max20830_id[] = { 85 {"max20830"}, 86 { } 87 }; 88 MODULE_DEVICE_TABLE(i2c, max20830_id); 89 90 static const struct of_device_id max20830_of_match[] = { 91 { .compatible = "adi,max20830" }, 92 { } 93 }; 94 MODULE_DEVICE_TABLE(of, max20830_of_match); 95 96 static struct i2c_driver max20830_driver = { 97 .driver = { 98 .name = "max20830", 99 .of_match_table = max20830_of_match, 100 }, 101 .probe = max20830_probe, 102 .id_table = max20830_id, 103 }; 104 105 module_i2c_driver(max20830_driver); 106 107 MODULE_AUTHOR("Alexis Czezar Torreno <alexisczezar.torreno@analog.com>"); 108 MODULE_DESCRIPTION("PMBus driver for Analog Devices MAX20830"); 109 MODULE_LICENSE("GPL"); 110 MODULE_IMPORT_NS("PMBUS"); 111