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charset="utf-8" Content-Transfer-Encoding: 8bit Message-ID: <20260730-dev-max20830c-v5-2-a7553f84ee74@analog.com> References: <20260730-dev-max20830c-v5-0-a7553f84ee74@analog.com> In-Reply-To: <20260730-dev-max20830c-v5-0-a7553f84ee74@analog.com> To: Guenter Roeck , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Jonathan Corbet , Shuah Khan CC: , , , , Alexis Czezar Torreno X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=ed25519-sha256; t=1785373424; l=4341; i=alexisczezar.torreno@analog.com; s=20250213; h=from:subject:message-id; bh=ta+gqkJOzk2z5y8MPlrhsU2CswcciVfxQMzcsris8Y4=; b=39nuxaxaxS32+AjGr7vX886Iw+lUsRYfh6HbQ+C9kfzXB+FSD+T0q/7dpqhKs1xOPpivuDZGR mYfbNIw6KAFBdWJ5sjHoJjGjyyjc0B2HCYdyd3fkCSB8brdlDoGD9PP X-Developer-Key: i=alexisczezar.torreno@analog.com; a=ed25519; pk=XpXmJnRjnsKdDil6YpOlj9+44S+XYXVFnxvkbmaZ+10= X-ADIRuleOP-NewSCL: Rule Triggered X-Proofpoint-ORIG-GUID: NU8jRuq2O4UjJIqHuuL2diAELjoFe_Bm X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNzMwMDAwNCBTYWx0ZWRfXxe0945rpgG3Z vQ4DV+58aFq9M9YXFwDV4tSFBbHDchjXFtDrb9tkB/nSZWYit4BxxjRXZqkf43X3ubwlp2QDyFD olR+Llo9jqXQdcsfG2X3Dezc0N3cloqEOpwp6LsQtHc7C2J1lGlhNQO3zPaFZJRVa9VLdYOsVjS tjen+dhFoePv9qfJvmyTzuxUCgXiBZkKFCcmOo3AuwZ8xriOjbt4/QzKXj0Wl4P2+NV5ZrDICzN kUetsAsJW+UxxXkc1nkIut6IOLWIT3SHUY+oqxjcNwc2GjhH8M0pIwWXCUV7uNVxmId5d4yesgC mgiYhD+cP5G9n+Lw3qK6b9WbtFyIXedD9WiEzEqkWijuWPlMkPm6EKZU61oIVeS4hTnmYrsDi3v Bk6olG1GDoHMHAVhzyZfhT/HQBICp9jJP90PkifVxLMK/94TgE98vyqEDoQece5J/s5rev95uM5 Vrah7BuknDVh2HGzeZA== X-Proofpoint-GUID: NU8jRuq2O4UjJIqHuuL2diAELjoFe_Bm X-Authority-Analysis: v=2.4 cv=OtN/DS/t c=1 sm=1 tr=0 ts=6a6aa30a cx=c_pps a=3WNzaoukacrqR9RwcOSAdA==:117 a=3WNzaoukacrqR9RwcOSAdA==:17 a=IkcTkHD0fZMA:10 a=RAioF0-LDSMA:10 a=VkNPw1HP01LnGYTKEx00:22 a=0sLvza09kfJOxVLZPwjg:22 a=N--XFCr6TIEc_64PeIT2:22 a=gAnH3GRIAAAA:8 a=c585p9qd8l5BjXVnlE8A:9 a=3ZKOabzyN94A:10 a=QEXdDO2ut3YA:10 X-Proofpoint-Spam-Info: AW1haW4tMjYwNzMwMDAwNCBTYWx0ZWRfX1iCBZFYvDsUI 5q8zcGp/ib7UHE5UYwP6WbTs3inZa7FXJcBpL1Tp5LJfL9T2nJKRiJepi8Blqh+G4FNCEETty9R VhZilhlRNLl9DaFEL7IgblngGov2EAiYR/ebqSmI1HpJl5E3MhRm X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-07-29_09,2026-07-29_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 clxscore=1015 phishscore=0 adultscore=0 priorityscore=1501 impostorscore=0 lowpriorityscore=0 bulkscore=0 spamscore=0 suspectscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2607300004 Implement support for external voltage divider scaling using the adi,vout-rfb1-ohms and adi,vout-rfb2-ohms device tree properties. When the desired output voltage exceeds VREF, a resistor divider (RFB1 and RFB2) is used to scale down the feedback voltage. The driver reads these resistor values from device tree and applies the scaling formula: VOUT_actual = VOUT_measured × (1 + RFB1/RFB2) The properties are optional. If not specified, the driver assumes no voltage divider is present and reports the raw VOUT reading. Signed-off-by: Alexis Czezar Torreno --- drivers/hwmon/pmbus/max20830.c | 65 +++++++++++++++++++++++++++++++++++++++++- 1 file changed, 64 insertions(+), 1 deletion(-) diff --git a/drivers/hwmon/pmbus/max20830.c b/drivers/hwmon/pmbus/max20830.c index cb2c23672166d641852199ca07eb716924f4f286..ddead72a8db5d6f8491cbfbf356db0f8de64da03 100644 --- a/drivers/hwmon/pmbus/max20830.c +++ b/drivers/hwmon/pmbus/max20830.c @@ -7,6 +7,7 @@ #include #include +#include #include #include #include @@ -14,6 +15,56 @@ #define MAX20830_IC_DEVICE_ID_LENGTH 9 +struct max20830_data { + struct pmbus_driver_info info; + u32 vout_rfb1; + u32 vout_rfb2; +}; + +/* + * 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, @@ -24,13 +75,25 @@ 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] = {}; + struct max20830_data *data; int 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)) return -ENODEV; @@ -78,7 +141,7 @@ static int max20830_probe(struct i2c_client *client) return dev_err_probe(&client->dev, -ENODEV, "Unsupported device: '%s'\n", buf); - return pmbus_do_probe(client, &max20830_info); + return pmbus_do_probe(client, &data->info); } static const struct i2c_device_id max20830_id[] = { -- 2.34.1