--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Hardware monitoring driver for MPS Multi-phase Digital VR Controllers
+ *
+ * Copyright (C) 2020 Nvidia Technologies Ltd.
+ */
+
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include "pmbus.h"
+
+/* Vendor specific registers. */
+#define MP2888_MFR_SYS_CONFIG 0x44
+#define MP2888_MFR_READ_CS1_2 0x73
+#define MP2888_MFR_READ_CS3_4 0x74
+#define MP2888_MFR_READ_CS5_6 0x75
+#define MP2888_MFR_READ_CS7_8 0x76
+#define MP2888_MFR_READ_CS9_10 0x77
+#define MP2888_MFR_VR_CONFIG1 0xe1
+
+#define MP2888_TOTAL_CURRENT_RESOLUTION BIT(3)
+#define MP2888_PHASE_CURRENT_RESOLUTION BIT(4)
+#define MP2888_DRMOS_KCS GENMASK(2, 0)
+#define MP2888_TEMP_UNIT 10
+#define MP2888_MAX_PHASE 10
+
+struct mp2888_data {
+ struct pmbus_driver_info info;
+ int total_curr_resolution;
+ int phase_curr_resolution;
+ int curr_sense_gain;
+};
+
+#define to_mp2888_data(x) container_of(x, struct mp2888_data, info)
+
+static int mp2888_read_byte_data(struct i2c_client *client, int page, int reg)
+{
+ switch (reg) {
+ case PMBUS_VOUT_MODE:
+ /* Enforce VOUT direct format. */
+ return PB_VOUT_MODE_DIRECT;
+ default:
+ return -ENODATA;
+ }
+}
+
+static int
+mp2888_current_sense_gain_and_resolution_get(struct i2c_client *client, struct mp2888_data *data)
+{
+ int ret;
+
+ /*
+ * Obtain DrMOS current sense gain of power stage from the register
+ * , bits 0-2. The value is selected as below:
+ * 00b - 5µA/A, 01b - 8.5µA/A, 10b - 9.7µA/A, 11b - 10µA/A. Other
+ * values are reserved.
+ */
+ ret = i2c_smbus_read_word_data(client, MP2888_MFR_SYS_CONFIG);
+ if (ret < 0)
+ return ret;
+
+ switch (ret & MP2888_DRMOS_KCS) {
+ case 0:
+ data->curr_sense_gain = 85;
+ break;
+ case 1:
+ data->curr_sense_gain = 97;
+ break;
+ case 2:
+ data->curr_sense_gain = 100;
+ break;
+ case 3:
+ data->curr_sense_gain = 50;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ /*
+ * Obtain resolution selector for total and phase current report and protection.
+ * 0: original resolution; 1: half resolution (in such case phase current value should
+ * be doubled.
+ */
+ data->total_curr_resolution = (ret & MP2888_TOTAL_CURRENT_RESOLUTION) >> 3;
+ data->phase_curr_resolution = (ret & MP2888_PHASE_CURRENT_RESOLUTION) >> 4;
+
+ return 0;
+}
+
+static int
+mp2888_read_phase(struct i2c_client *client, struct mp2888_data *data, int page, int phase, u8 reg)
+{
+ int ret;
+
+ ret = pmbus_read_word_data(client, page, phase, reg);
+ if (ret < 0)
+ return ret;
+
+ if (!((phase + 1) % 2))
+ ret >>= 8;
+ ret &= 0xff;
+
+ /*
+ * Output value is calculated as: (READ_CSx / 80 – 1.23) / (Kcs * Rcs)
+ * where:
+ * - Kcs is the DrMOS current sense gain of power stage, which is obtained from the
+ * register MP2888_MFR_VR_CONFIG1, bits 13-12 with the following selection of DrMOS
+ * (data->curr_sense_gain):
+ * 00b - 5µA/A, 01b - 8.5µA/A, 10b - 9.7µA/A, 11b - 10µA/A.
+ * - Rcs is the internal phase current sense resistor. This parameter depends on hardware
+ * assembly. By default it is set to 1kΩ. In case of different assembly, user should
+ * scale this parameter by dividing it by Rcs.
+ * If phase current resolution bit is set to 1, READ_CSx value should be doubled.
+ * Note, that current phase sensing, providing by the device is not accurate. This is
+ * because sampling of current occurrence of bit weight has a big deviation, especially for
+ * light load.
+ */
+ ret = DIV_ROUND_CLOSEST(ret * 100 - 9800, data->curr_sense_gain);
+ ret = (data->phase_curr_resolution) ? ret * 2 : ret;
+ /* Scale according to total current resolution. */
+ ret = (data->total_curr_resolution) ? ret * 8 : ret * 4;
+ return ret;
+}
+
+static int
+mp2888_read_phases(struct i2c_client *client, struct mp2888_data *data, int page, int phase)
+{
+ int ret;
+
+ switch (phase) {
+ case 0 ... 1:
+ ret = mp2888_read_phase(client, data, page, phase, MP2888_MFR_READ_CS1_2);
+ break;
+ case 2 ... 3:
+ ret = mp2888_read_phase(client, data, page, phase, MP2888_MFR_READ_CS3_4);
+ break;
+ case 4 ... 5:
+ ret = mp2888_read_phase(client, data, page, phase, MP2888_MFR_READ_CS5_6);
+ break;
+ case 6 ... 7:
+ ret = mp2888_read_phase(client, data, page, phase, MP2888_MFR_READ_CS7_8);
+ break;
+ case 8 ... 9:
+ ret = mp2888_read_phase(client, data, page, phase, MP2888_MFR_READ_CS9_10);
+ break;
+ default:
+ return -ENODATA;
+ }
+ return ret;
+}
+
+static int mp2888_read_word_data(struct i2c_client *client, int page, int phase, int reg)
+{
+ const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
+ struct mp2888_data *data = to_mp2888_data(info);
+ int ret;
+
+ switch (reg) {
+ case PMBUS_READ_VIN:
+ ret = pmbus_read_word_data(client, page, phase, reg);
+ if (ret <= 0)
+ return ret;
+
+ /*
+ * READ_VIN requires fixup to scale it to linear11 format. Register data format
+ * provides 10 bits for mantissa and 6 bits for exponent. Bits 15:10 are set with
+ * the fixed value 111011b.
+ */
+ ret = (ret & GENMASK(9, 0)) | ((ret & GENMASK(31, 10)) << 1);
+ break;
+ case PMBUS_OT_WARN_LIMIT:
+ ret = pmbus_read_word_data(client, page, phase, reg);
+ if (ret < 0)
+ return ret;
+ /*
+ * Chip reports limits in degrees C, but the actual temperature in 10th of
+ * degrees C - scaling is needed to match both.
+ */
+ ret *= MP2888_TEMP_UNIT;
+ break;
+ case PMBUS_READ_IOUT:
+ if (phase != 0xff)
+ return mp2888_read_phases(client, data, page, phase);
+
+ ret = pmbus_read_word_data(client, page, phase, reg);
+ if (ret < 0)
+ return ret;
+ /*
+ * READ_IOUT register has unused bits 15:12 with fixed value 1110b. Clear these
+ * bits and scale with total current resolution. Data is provided in direct format.
+ */
+ ret &= GENMASK(11, 0);
+ ret = data->total_curr_resolution ? ret * 2 : ret;
+ break;
+ case PMBUS_IOUT_OC_WARN_LIMIT:
+ ret = pmbus_read_word_data(client, page, phase, reg);
+ if (ret < 0)
+ return ret;
+ ret &= GENMASK(9, 0);
+ /*
+ * Chip reports limits with resolution 1A or 2A, if total current resolution bit is
+ * set 1. Actual current is reported with 0.25A or respectively 0.5A resolution.
+ * Scaling is needed to match both.
+ */
+ ret = data->total_curr_resolution ? ret * 8 : ret * 4;
+ break;
+ case PMBUS_READ_POUT:
+ case PMBUS_READ_PIN:
+ ret = pmbus_read_word_data(client, page, phase, reg);
+ if (ret < 0)
+ return ret;
+ ret = data->total_curr_resolution ? ret * 2 : ret;
+ break;
+ case PMBUS_POUT_OP_WARN_LIMIT:
+ ret = pmbus_read_word_data(client, page, phase, reg);
+ if (ret < 0)
+ return ret;
+ /*
+ * Chip reports limits with resolution 1W or 2W, if total current resolution bit is
+ * set 1. Actual power is reported with 0.5W or 1W respectively resolution. Scaling
+ * is needed to match both.
+ */
+ ret = data->total_curr_resolution ? ret * 4 : ret * 2;
+ break;
+ /*
+ * The below registers are not implemented by device or implemented not according to the
+ * spec. Skip all of them to avoid exposing non-relevant inputs to sysfs.
+ */
+ case PMBUS_OT_FAULT_LIMIT:
+ case PMBUS_UT_WARN_LIMIT:
+ case PMBUS_UT_FAULT_LIMIT:
+ case PMBUS_VIN_UV_FAULT_LIMIT:
+ case PMBUS_VOUT_UV_WARN_LIMIT:
+ case PMBUS_VOUT_OV_WARN_LIMIT:
+ case PMBUS_VOUT_UV_FAULT_LIMIT:
+ case PMBUS_VOUT_OV_FAULT_LIMIT:
+ case PMBUS_VIN_OV_WARN_LIMIT:
+ case PMBUS_IOUT_OC_LV_FAULT_LIMIT:
+ case PMBUS_IOUT_OC_FAULT_LIMIT:
+ case PMBUS_POUT_MAX:
+ case PMBUS_IOUT_UC_FAULT_LIMIT:
+ case PMBUS_POUT_OP_FAULT_LIMIT:
+ case PMBUS_PIN_OP_WARN_LIMIT:
+ case PMBUS_MFR_VIN_MIN:
+ case PMBUS_MFR_VOUT_MIN:
+ case PMBUS_MFR_VIN_MAX:
+ case PMBUS_MFR_VOUT_MAX:
+ case PMBUS_MFR_IIN_MAX:
+ case PMBUS_MFR_IOUT_MAX:
+ case PMBUS_MFR_PIN_MAX:
+ case PMBUS_MFR_POUT_MAX:
+ case PMBUS_MFR_MAX_TEMP_1:
+ return -ENXIO;
+ default:
+ return -ENODATA;
+ }
+
+ return ret;
+}
+
+static int mp2888_write_word_data(struct i2c_client *client, int page, int reg, u16 word)
+{
+ const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
+ struct mp2888_data *data = to_mp2888_data(info);
+
+ switch (reg) {
+ case PMBUS_OT_WARN_LIMIT:
+ word = DIV_ROUND_CLOSEST(word, MP2888_TEMP_UNIT);
+ /* Drop unused bits 15:8. */
+ word = clamp_val(word, 0, GENMASK(7, 0));
+ break;
+ case PMBUS_IOUT_OC_WARN_LIMIT:
+ /* Fix limit according to total curent resolution. */
+ word = data->total_curr_resolution ? DIV_ROUND_CLOSEST(word, 8) :
+ DIV_ROUND_CLOSEST(word, 4);
+ /* Drop unused bits 15:10. */
+ word = clamp_val(word, 0, GENMASK(9, 0));
+ break;
+ case PMBUS_POUT_OP_WARN_LIMIT:
+ /* Fix limit according to total curent resolution. */
+ word = data->total_curr_resolution ? DIV_ROUND_CLOSEST(word, 4) :
+ DIV_ROUND_CLOSEST(word, 2);
+ /* Drop unused bits 15:10. */
+ word = clamp_val(word, 0, GENMASK(9, 0));
+ break;
+ default:
+ return -ENODATA;
+ }
+ return pmbus_write_word_data(client, page, reg, word);
+}
+
+static int
+mp2888_identify_multiphase(struct i2c_client *client, struct mp2888_data *data,
+ struct pmbus_driver_info *info)
+{
+ int ret;
+
+ ret = i2c_smbus_write_byte_data(client, PMBUS_PAGE, 0);
+ if (ret < 0)
+ return ret;
+
+ /* Identify multiphase number - could be from 1 to 10. */
+ ret = i2c_smbus_read_word_data(client, MP2888_MFR_VR_CONFIG1);
+ if (ret <= 0)
+ return ret;
+
+ info->phases[0] = ret & GENMASK(3, 0);
+
+ /*
+ * The device provides a total of 10 PWM pins, and can be configured to different phase
+ * count applications for rail.
+ */
+ if (info->phases[0] > MP2888_MAX_PHASE)
+ return -EINVAL;
+
+ return 0;
+}
+
+static struct pmbus_driver_info mp2888_info = {
+ .pages = 1,
+ .format[PSC_VOLTAGE_IN] = linear,
+ .format[PSC_VOLTAGE_OUT] = direct,
+ .format[PSC_TEMPERATURE] = direct,
+ .format[PSC_CURRENT_IN] = linear,
+ .format[PSC_CURRENT_OUT] = direct,
+ .format[PSC_POWER] = direct,
+ .m[PSC_TEMPERATURE] = 1,
+ .R[PSC_TEMPERATURE] = 1,
+ .m[PSC_VOLTAGE_OUT] = 1,
+ .R[PSC_VOLTAGE_OUT] = 3,
+ .m[PSC_CURRENT_OUT] = 4,
+ .m[PSC_POWER] = 1,
+ .func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT | PMBUS_HAVE_IOUT |
+ PMBUS_HAVE_STATUS_IOUT | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP |
+ PMBUS_HAVE_POUT | PMBUS_HAVE_PIN | PMBUS_HAVE_STATUS_INPUT |
+ PMBUS_PHASE_VIRTUAL,
+ .pfunc[0] = PMBUS_HAVE_IOUT,
+ .pfunc[1] = PMBUS_HAVE_IOUT,
+ .pfunc[2] = PMBUS_HAVE_IOUT,
+ .pfunc[3] = PMBUS_HAVE_IOUT,
+ .pfunc[4] = PMBUS_HAVE_IOUT,
+ .pfunc[5] = PMBUS_HAVE_IOUT,
+ .pfunc[6] = PMBUS_HAVE_IOUT,
+ .pfunc[7] = PMBUS_HAVE_IOUT,
+ .pfunc[8] = PMBUS_HAVE_IOUT,
+ .pfunc[9] = PMBUS_HAVE_IOUT,
+ .read_byte_data = mp2888_read_byte_data,
+ .read_word_data = mp2888_read_word_data,
+ .write_word_data = mp2888_write_word_data,
+};
+
+static int mp2888_probe(struct i2c_client *client)
+{
+ struct pmbus_driver_info *info;
+ struct mp2888_data *data;
+ int ret;
+
+ data = devm_kzalloc(&client->dev, sizeof(struct mp2888_data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ memcpy(&data->info, &mp2888_info, sizeof(*info));
+ info = &data->info;
+
+ /* Identify multiphase configuration. */
+ ret = mp2888_identify_multiphase(client, data, info);
+ if (ret)
+ return ret;
+
+ /* Obtain current sense gain of power stage and current resolution. */
+ ret = mp2888_current_sense_gain_and_resolution_get(client, data);
+ if (ret)
+ return ret;
+
+ return pmbus_do_probe(client, info);
+}
+
+static const struct i2c_device_id mp2888_id[] = {
+ {"mp2888", 0},
+ {}
+};
+
+MODULE_DEVICE_TABLE(i2c, mp2888_id);
+
+static const struct of_device_id __maybe_unused mp2888_of_match[] = {
+ {.compatible = "mps,mp2888"},
+ {}
+};
+MODULE_DEVICE_TABLE(of, mp2888_of_match);
+
+static struct i2c_driver mp2888_driver = {
+ .driver = {
+ .name = "mp2888",
+ .of_match_table = of_match_ptr(mp2888_of_match),
+ },
+ .probe_new = mp2888_probe,
+ .id_table = mp2888_id,
+};
+
+module_i2c_driver(mp2888_driver);
+
+MODULE_AUTHOR("Vadim Pasternak <vadimp@nvidia.com>");
+MODULE_DESCRIPTION("PMBus driver for MPS MP2888 device");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(PMBUS);
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