diff --git a/Documentation/devicetree/bindings/hwmon/pmbus/adi,max20830.yaml b/Documentation/devicetree/bindings/hwmon/pmbus/adi,max20830.yaml index 1625dd59417f1b..b8ca8ec0446fae 100644 --- a/Documentation/devicetree/bindings/hwmon/pmbus/adi,max20830.yaml +++ b/Documentation/devicetree/bindings/hwmon/pmbus/adi,max20830.yaml @@ -22,7 +22,13 @@ allOf: properties: compatible: - const: adi,max20830 + oneOf: + - const: adi,max20830 + - items: + - enum: + - adi,max20830c + - adi,max20840c + - const: adi,max20830 # Fallback compatible reg: maxItems: 1 @@ -39,16 +45,36 @@ properties: description: Optional 2.5V to 5.5V LDO input supply. + enable-gpios: + description: + GPIO connected to the EN (enable) pin. + maxItems: 1 + pwr-good-gpios: description: GPIO connected to the power-good status output pin. maxItems: 1 + adi,vout-rfb1-ohms: + description: + Top feedback resistor (RFB1) value in ohms for VOUT sensing divider. + When the desired output voltage is higher than VREF, a resistor divider + is required. VOUT = VREF × (1 + RFB1/RFB2) + + adi,vout-rfb2-ohms: + description: + Bottom feedback resistor (RFB2) value in ohms for VOUT sensing divider. + Datasheet recommends that RFB2 does not exceed 2.5kΩ. + required: - compatible - reg - vddh-supply +dependencies: + adi,vout-rfb1-ohms: ['adi,vout-rfb2-ohms'] + adi,vout-rfb2-ohms: ['adi,vout-rfb1-ohms'] + unevaluatedProperties: false examples: @@ -61,6 +87,8 @@ examples: compatible = "adi,max20830"; reg = <0x30>; vddh-supply = <&vddh>; + adi,vout-rfb1-ohms = <10000>; + adi,vout-rfb2-ohms = <2000>; }; }; ... diff --git a/Documentation/hwmon/max20830.rst b/Documentation/hwmon/max20830.rst index 936e409dcc5c08..b850f3b6e40d1f 100644 --- a/Documentation/hwmon/max20830.rst +++ b/Documentation/hwmon/max20830.rst @@ -13,6 +13,22 @@ Supported chips: Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/max20830.pdf + * Analog Devices MAX20830C + + Prefix: 'max20830c' + + Addresses scanned: - + + Datasheet: + + * Analog Devices MAX20840C + + Prefix: 'max20840c' + + Addresses scanned: - + + Datasheet: + Author: - Alexis Czezar Torreno @@ -21,12 +37,13 @@ Author: Description ----------- -This driver supports hardware monitoring for Analog Devices MAX20830 -Step-Down Switching Regulator with PMBus Interface. +This driver supports hardware monitoring for Analog Devices MAX20830, MAX20830C +and MAX20840C. These are Step-Down Switching Regulator with PMBus Interface. -The MAX20830 is a 2.7V to 16V, 30A fully integrated step-down DC-DC switching -regulator. Through the PMBus interface, the device can monitor input/output -voltages, output current and temperature. +MAX20830, and MAX20830C are 2.7V to 16V, 30A fully integrated step-down DC-DC +switching regulators. MAX20840C is similar but can reach 40A. Through the PMBus +interface, these devices can monitor input/output voltages, output current and +temperature. The driver is a client driver to the core PMBus driver. Please see Documentation/hwmon/pmbus.rst for details on PMBus client drivers. diff --git a/drivers/hwmon/pmbus/max20830.c b/drivers/hwmon/pmbus/max20830.c index e3470118fd36c8..94433deda0113a 100644 --- a/drivers/hwmon/pmbus/max20830.c +++ b/drivers/hwmon/pmbus/max20830.c @@ -7,12 +7,70 @@ #include #include +#include +#include #include #include #include "pmbus.h" #define MAX20830_IC_DEVICE_ID_LENGTH 9 +struct max20830_data { + struct pmbus_driver_info info; + u32 vout_rfb1; + u32 vout_rfb2; +}; + +static const char * const supported_chip_ids[] = { + "MAX20830", + "MAX20830C", + "MAX20840C", +}; + +/* + * MAX20830 only supports READ_VOUT for VOUT monitoring. + * + * Limit registers (VOUT_OV_WARN_LIMIT, VOUT_OV_FAULT_LIMIT, etc.) are not + * supported by this driver and return -ENODATA. This means sysfs attributes + * like in1_max, in1_crit, etc. will not be available. Only in1_input (the + * scaled output voltage) is supported. + * + * MAX20830 uses an external resistor divider for voltage sensing: + * - VOUT_COMMAND and VOUT_MAX set the reference voltage at the feedback pin + * - READ_VOUT reports the feedback voltage, which needs to be scaled for actual + * output voltage + * + * Scaling formula: vout_actual = vout_fb × (1 + RFB1 / RFB2) + * + * If regulator support is added in the future, some adjustments are needed to + * ensure correct feedback voltages are set. + */ +static int max20830_read_word_data(struct i2c_client *client, int page, + int phase, int reg) +{ + const struct pmbus_driver_info *info = pmbus_get_driver_info(client); + const struct max20830_data *data = container_of(info, struct max20830_data, info); + int ret; + u64 temp; + + switch (reg) { + case PMBUS_READ_VOUT: + ret = pmbus_read_word_data(client, page, phase, reg); + if (ret < 0) + return ret; + + /* Apply voltage divider scaling if resistors are non-zero */ + if (data->vout_rfb1 && data->vout_rfb2) { + temp = (u64)data->vout_rfb1 + (u64)data->vout_rfb2; + temp = DIV_ROUND_CLOSEST_ULL((u64)ret * temp, data->vout_rfb2); + ret = clamp_val(temp, 0, 0xFFFF); + } + return ret; + default: + return -ENODATA; + } +} + static struct pmbus_driver_info max20830_info = { .pages = 1, .format[PSC_VOLTAGE_IN] = linear, @@ -23,12 +81,24 @@ static struct pmbus_driver_info max20830_info = { PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_VOUT | PMBUS_HAVE_STATUS_IOUT | PMBUS_HAVE_STATUS_INPUT | PMBUS_HAVE_STATUS_TEMP, + .read_word_data = max20830_read_word_data, }; static int max20830_probe(struct i2c_client *client) { u8 buf[I2C_SMBUS_BLOCK_MAX + 1] = {}; - int ret; + struct max20830_data *data; + int i, ret; + + data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + data->info = max20830_info; + + /* Read optional voltage divider resistor values */ + device_property_read_u32(&client->dev, "adi,vout-rfb1-ohms", &data->vout_rfb1); + device_property_read_u32(&client->dev, "adi,vout-rfb2-ohms", &data->vout_rfb2); if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_BLOCK_DATA) && !i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_I2C_BLOCK)) @@ -40,13 +110,12 @@ static int max20830_probe(struct i2c_client *client) * which do not support SMBus block reads. */ if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_BLOCK_DATA)) { - /* Reads 9 Data bytes from MAX20830 */ ret = i2c_smbus_read_block_data(client, PMBUS_IC_DEVICE_ID, buf); if (ret < 0) return dev_err_probe(&client->dev, ret, "Failed to read IC_DEVICE_ID\n"); } else { - /* Reads 1 length byte + 9 Data bytes from MAX20830 */ + /* Reads 1 length byte + data bytes */ ret = i2c_smbus_read_i2c_block_data(client, PMBUS_IC_DEVICE_ID, MAX20830_IC_DEVICE_ID_LENGTH + 1, buf); @@ -62,22 +131,27 @@ static int max20830_probe(struct i2c_client *client) ret = ret - 1; } - /* - * MAX20830 IC_DEVICE_ID sends string data "MAX20830\0". - * Return value should at least be 9 bytes of data. - */ + /* Verify we read the expected number of bytes */ if (ret < MAX20830_IC_DEVICE_ID_LENGTH) return dev_err_probe(&client->dev, -ENODEV, - "IC_DEVICE_ID too short: expected at least 9 bytes, got %d\n", - ret); + "IC_DEVICE_ID too short: expected %d bytes, got %d\n", + MAX20830_IC_DEVICE_ID_LENGTH, ret); + + /* Null-terminate the string */ + buf[ret] = '\0'; + + /* Verify the device ID matches what we expect */ + for (i = 0; i < ARRAY_SIZE(supported_chip_ids); i++) { + if (!strcmp(buf, supported_chip_ids[i])) + break; + } - /* 9 bytes of data, buf[0]-buf[7] = "MAX20830", buf[8] = '\0' */ - buf[MAX20830_IC_DEVICE_ID_LENGTH - 1] = '\0'; - if (strncmp(buf, "MAX20830", MAX20830_IC_DEVICE_ID_LENGTH - 1)) + /* No match found - unsupported device */ + if (i == ARRAY_SIZE(supported_chip_ids)) return dev_err_probe(&client->dev, -ENODEV, - "Unsupported device: '%s'\n", buf); + "Unsupported device: '%*pE'\n", ret, buf); - return pmbus_do_probe(client, &max20830_info); + return pmbus_do_probe(client, &data->info); } static const struct i2c_device_id max20830_id[] = {