--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Hardware monitoring driver for MPS2856/2857
+ * Monolithic Power Systems VR Controllers
+ *
+ * Copyright (C) 2023 Quanta Computer lnc.
+ */
+
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pmbus.h>
+#include "pmbus.h"
+
+/* Vendor specific registers. */
+#define MP2856_MFR_VR_MULTI_CONFIG_R1 0x0d
+#define MP2856_MFR_VR_MULTI_CONFIG_R2 0x1d
+
+#define MP2856_MUL1_BOOT_SR_R2 0x10
+#define MP2856_VR_ACTIVE BIT(15)
+
+#define MP2856_MFR_VR_CONFIG2 0x5e
+#define MP2856_VOUT_MODE BIT(11)
+
+#define MP2856_MFR_VR_CONFIG1 0x68
+#define MP2856_DRMOS_KCS GENMASK(13, 12)
+
+#define MP2856_MFR_READ_CS1_2_R1 0x82
+#define MP2856_MFR_READ_CS3_4_R1 0x83
+#define MP2856_MFR_READ_CS5_6_R1 0x84
+#define MP2856_MFR_READ_CS7_8_R1 0x85
+#define MP2856_MFR_READ_CS9_10_R1 0x86
+#define MP2856_MFR_READ_CS11_12_R1 0x87
+
+#define MP2856_MFR_READ_CS1_2_R2 0x85
+#define MP2856_MFR_READ_CS3_4_R2 0x86
+#define MP2856_MFR_READ_CS5_6_R2 0x87
+
+#define MP2856_MAX_PHASE_RAIL1 8
+#define MP2856_MAX_PHASE_RAIL2 4
+
+#define MP2857_MAX_PHASE_RAIL1 12
+#define MP2857_MAX_PHASE_RAIL2 4
+
+#define MP2856_PAGE_NUM 2
+
+enum chips { mp2856 = 1, mp2857 };
+
+static const int mp2856_max_phases[][MP2856_PAGE_NUM] = {
+ [mp2856] = { MP2856_MAX_PHASE_RAIL1, MP2856_MAX_PHASE_RAIL2 },
+ [mp2857] = { MP2857_MAX_PHASE_RAIL1, MP2857_MAX_PHASE_RAIL2 },
+};
+
+static const struct i2c_device_id mp2856_id[] = {
+ {"mp2856", mp2856},
+ {"mp2857", mp2857},
+ {}
+};
+
+MODULE_DEVICE_TABLE(i2c, mp2856_id);
+
+struct mp2856_data {
+ struct pmbus_driver_info info;
+ int vout_format[MP2856_PAGE_NUM];
+ int curr_sense_gain[MP2856_PAGE_NUM];
+ int max_phases[MP2856_PAGE_NUM];
+ enum chips chip_id;
+};
+
+#define to_mp2856_data(x) container_of(x, struct mp2856_data, info)
+
+#define MAX_LIN_MANTISSA (1023 * 1000)
+#define MIN_LIN_MANTISSA (511 * 1000)
+
+static u16 val2linear11(s64 val)
+{
+ s16 exponent = 0, mantissa;
+ bool negative = false;
+
+ if (val == 0)
+ return 0;
+
+ if (val < 0) {
+ negative = true;
+ val = -val;
+ }
+
+ /* Reduce large mantissa until it fits into 10 bit */
+ while (val >= MAX_LIN_MANTISSA && exponent < 15) {
+ exponent++;
+ val >>= 1;
+ }
+ /* Increase small mantissa to improve precision */
+ while (val < MIN_LIN_MANTISSA && exponent > -15) {
+ exponent--;
+ val <<= 1;
+ }
+
+ /* Convert mantissa from milli-units to units */
+ mantissa = clamp_val(DIV_ROUND_CLOSEST_ULL(val, 1000), 0, 0x3ff);
+
+ /* restore sign */
+ if (negative)
+ mantissa = -mantissa;
+
+ /* Convert to 5 bit exponent, 11 bit mantissa */
+ return (mantissa & 0x7ff) | ((exponent << 11) & 0xf800);
+}
+
+static int
+mp2856_read_word_helper(struct i2c_client *client, int page, int phase, u8 reg,
+ u16 mask)
+{
+ int ret = pmbus_read_word_data(client, page, phase, reg);
+
+ return (ret > 0) ? ret & mask : ret;
+}
+
+static int
+mp2856_read_vout(struct i2c_client *client, struct mp2856_data *data, int page,
+ int phase, u8 reg)
+{
+ int ret;
+
+ ret = mp2856_read_word_helper(client, page, phase, reg,
+ GENMASK(9, 0));
+ if (ret < 0)
+ return ret;
+
+ /* convert vout result to direct format */
+ ret = (data->vout_format[page] == vid) ?
+ ((ret + 49) * 5) : ((ret * 1000) >> 8);
+
+ return ret;
+}
+
+static int
+mp2856_read_phase(struct i2c_client *client, struct mp2856_data *data,
+ int page, int phase, u8 reg)
+{
+ int ret;
+ int val;
+
+ ret = pmbus_read_word_data(client, page, phase, reg);
+ if (ret < 0)
+ return ret;
+
+ if (!((phase + 1) % MP2856_PAGE_NUM))
+ ret >>= 8;
+ ret &= 0xff;
+
+ /*
+ * Output value is calculated as: (READ_CSx * 12.5mV - 1.23V) / (Kcs * Rcs)
+ */
+ val = (ret * 125) - 12300;
+
+ return val2linear11(val);
+}
+
+static int
+mp2856_read_phases(struct i2c_client *client, struct mp2856_data *data,
+ int page, int phase)
+{
+ int ret;
+
+ if (page == 0) {
+ switch (phase) {
+ case 0 ... 1:
+ ret = mp2856_read_phase(client, data, page, phase,
+ MP2856_MFR_READ_CS1_2_R1);
+ break;
+ case 2 ... 3:
+ ret = mp2856_read_phase(client, data, page, phase,
+ MP2856_MFR_READ_CS3_4_R1);
+ break;
+ case 4 ... 5:
+ ret = mp2856_read_phase(client, data, page, phase,
+ MP2856_MFR_READ_CS5_6_R1);
+ break;
+ case 6 ... 7:
+ ret = mp2856_read_phase(client, data, page, phase,
+ MP2856_MFR_READ_CS7_8_R1);
+ break;
+ default:
+ return -ENODATA;
+ }
+ } else {
+ switch (phase) {
+ case 0 ... 1:
+ ret = mp2856_read_phase(client, data, page, phase,
+ MP2856_MFR_READ_CS1_2_R2);
+ break;
+ case 2 ... 3:
+ ret = mp2856_read_phase(client, data, page, phase,
+ MP2856_MFR_READ_CS1_2_R2);
+ break;
+ default:
+ return -ENODATA;
+ }
+ }
+ return ret;
+}
+
+static int
+mp2856_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 mp2856_data *data = to_mp2856_data(info);
+ int ret;
+
+ switch (reg) {
+ case PMBUS_READ_VOUT:
+ ret = mp2856_read_vout(client, data, page, phase, reg);
+ break;
+ case PMBUS_READ_IOUT:
+ if (phase != 0xff)
+ ret = mp2856_read_phases(client, data, page, phase);
+ else
+ ret = pmbus_read_word_data(client, page, phase, reg);
+ break;
+ default:
+ return -ENODATA;
+ }
+
+ return ret;
+}
+
+static int
+mp2856_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
+mp2856_identify_multiphase(struct i2c_client *client, u8 reg, u8 max_phase,
+ u16 mask)
+{
+ int ret;
+
+ ret = i2c_smbus_write_byte_data(client, PMBUS_PAGE, 2);
+ if (ret < 0)
+ return ret;
+
+ ret = i2c_smbus_read_word_data(client, reg);
+ if (ret < 0)
+ return ret;
+
+ ret &= mask;
+ return (ret >= max_phase) ? max_phase : ret;
+}
+
+static int
+mp2856_identify_multiphase_rail1(struct i2c_client *client,
+ struct mp2856_data *data)
+{
+ int ret, i;
+
+ ret = mp2856_identify_multiphase(client, MP2856_MFR_VR_MULTI_CONFIG_R1,
+ MP2856_MAX_PHASE_RAIL1, GENMASK(3, 0));
+ if (ret < 0)
+ return ret;
+
+ data->info.phases[0] = (ret > data->max_phases[0]) ?
+ data->max_phases[0] : ret;
+
+ for (i = 0 ; i < data->info.phases[0]; i++)
+ data->info.pfunc[i] |= PMBUS_HAVE_IOUT;
+
+ return 0;
+}
+
+static int
+mp2856_identify_multiphase_rail2(struct i2c_client *client,
+ struct mp2856_data *data)
+{
+ int ret, i;
+
+ ret = mp2856_identify_multiphase(client, MP2856_MFR_VR_MULTI_CONFIG_R2,
+ MP2856_MAX_PHASE_RAIL2, GENMASK(2, 0));
+ if (ret < 0)
+ return ret;
+
+ data->info.phases[1] = (ret > data->max_phases[1]) ?
+ data->max_phases[1] : ret;
+
+ for (i = 0 ; i < data->info.phases[0]; i++)
+ data->info.pfunc[i] |= PMBUS_HAVE_IOUT;
+
+ return 0;
+}
+
+static int
+mp2856_current_sense_gain_get(struct i2c_client *client,
+ struct mp2856_data *data)
+{
+ int i, ret;
+
+ /*
+ * Obtain DrMOS current sense gain of power stage from the register
+ * MP2856_MFR_VR_CONFIG1, bits 13-12. The value is selected as below:
+ * 00b - 5µA/A, 01b - 8.5µA/A, 10b - 9.7µA/A, 11b - 10µA/A. Other
+ * values are invalid.
+ */
+ for (i = 0 ; i < data->info.pages; i++) {
+ ret = i2c_smbus_write_byte_data(client, PMBUS_PAGE, i);
+ if (ret < 0)
+ return ret;
+ ret = i2c_smbus_read_word_data(client,
+ MP2856_MFR_VR_CONFIG1);
+ if (ret < 0)
+ return ret;
+
+ switch ((ret & MP2856_DRMOS_KCS) >> 12) {
+ case 0:
+ data->curr_sense_gain[i] = 50;
+ break;
+ case 1:
+ data->curr_sense_gain[i] = 85;
+ break;
+ case 2:
+ data->curr_sense_gain[i] = 97;
+ break;
+ default:
+ data->curr_sense_gain[i] = 100;
+ break;
+ }
+ }
+ return 0;
+}
+
+static int
+mp2856_identify_vout_format(struct i2c_client *client,
+ struct mp2856_data *data)
+{
+ int i, ret;
+
+ for (i = 0; i < data->info.pages; i++) {
+ ret = i2c_smbus_write_byte_data(client, PMBUS_PAGE, i);
+ if (ret < 0)
+ return ret;
+
+ ret = i2c_smbus_read_word_data(client, MP2856_MFR_VR_CONFIG2);
+ if (ret < 0)
+ return ret;
+
+ data->vout_format[i] = (ret & MP2856_VOUT_MODE) ? linear : vid;
+ }
+ return 0;
+}
+
+static bool
+mp2856_is_rail2_active(struct i2c_client *client)
+{
+ int ret;
+
+ ret = i2c_smbus_write_byte_data(client, PMBUS_PAGE, 2);
+ if (ret < 0)
+ return true;
+
+ ret = i2c_smbus_read_word_data(client, MP2856_MUL1_BOOT_SR_R2);
+ if (ret < 0)
+ return true;
+
+ return (ret & MP2856_VR_ACTIVE) ? true : false;
+}
+
+static struct pmbus_driver_info mp2856_info = {
+ .pages = MP2856_PAGE_NUM,
+ .format[PSC_VOLTAGE_IN] = linear,
+ .format[PSC_VOLTAGE_OUT] = direct,
+ .format[PSC_TEMPERATURE] = linear,
+ .format[PSC_CURRENT_IN] = linear,
+ .format[PSC_CURRENT_OUT] = linear,
+ .format[PSC_POWER] = linear,
+ .m[PSC_VOLTAGE_OUT] = 1,
+ .R[PSC_VOLTAGE_OUT] = 3,
+ .func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT |
+ PMBUS_HAVE_IIN | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT |
+ PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP | PMBUS_HAVE_POUT |
+ PMBUS_HAVE_PIN | PMBUS_HAVE_STATUS_INPUT,
+ .func[1] = PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT | PMBUS_HAVE_IOUT |
+ PMBUS_HAVE_STATUS_IOUT | PMBUS_HAVE_POUT | PMBUS_HAVE_TEMP,
+ .read_byte_data = mp2856_read_byte_data,
+ .read_word_data = mp2856_read_word_data,
+};
+
+static int mp2856_probe(struct i2c_client *client)
+{
+ struct pmbus_driver_info *info;
+ struct mp2856_data *data;
+ int ret;
+
+ data = devm_kzalloc(&client->dev, sizeof(struct mp2856_data),
+ GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ data->chip_id = (enum chips)(uintptr_t)i2c_get_match_data(client);
+
+ memcpy(data->max_phases, mp2856_max_phases[data->chip_id],
+ sizeof(data->max_phases));
+
+ memcpy(&data->info, &mp2856_info, sizeof(*info));
+ info = &data->info;
+
+ /* Identify multiphase configuration. */
+ ret = mp2856_identify_multiphase_rail1(client, data);
+ if (ret < 0)
+ return ret;
+
+ if (mp2856_is_rail2_active(client)) {
+ ret = mp2856_identify_multiphase_rail2(client, data);
+ if (ret < 0)
+ return ret;
+ } else {
+ /* rail2 is not active */
+ info->pages = 1;
+ }
+
+ /* Obtain current sense gain of power stage. */
+ ret = mp2856_current_sense_gain_get(client, data);
+ if (ret)
+ return ret;
+
+ /* Identify vout format. */
+ ret = mp2856_identify_vout_format(client, data);
+ if (ret)
+ return ret;
+
+ /* set the device to page 0 */
+ i2c_smbus_write_byte_data(client, PMBUS_PAGE, 0);
+
+ return pmbus_do_probe(client, info);
+}
+
+static const struct of_device_id __maybe_unused mp2856_of_match[] = {
+ {.compatible = "mps,mp2856", .data = (void *)mp2856},
+ {.compatible = "mps,mp2857", .data = (void *)mp2857},
+ {}
+};
+MODULE_DEVICE_TABLE(of, mp2856_of_match);
+
+static struct i2c_driver mp2856_driver = {
+ .driver = {
+ .name = "mp2856",
+ .of_match_table = mp2856_of_match,
+ },
+ .probe = mp2856_probe,
+ .id_table = mp2856_id,
+};
+
+module_i2c_driver(mp2856_driver);
+
+MODULE_AUTHOR("Peter Yin <peter.yin@quantatw.com>");
+MODULE_DESCRIPTION("PMBus driver for MPS MP2856/MP2857 device");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(PMBUS);
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