]> git.ipfire.org Git - thirdparty/kernel/linux.git/commitdiff
hwmon: add MP2891 driver
authorNoah Wang <noahwang.wang@outlook.com>
Wed, 26 Jun 2024 09:46:01 +0000 (17:46 +0800)
committerGuenter Roeck <linux@roeck-us.net>
Fri, 28 Jun 2024 17:27:47 +0000 (10:27 -0700)
Add support for MPS VR controller mp2891. This driver exposes
telemetry and limit value readings and writtings.

Signed-off-by: Noah Wang <noahwang.wang@outlook.com>
Link: https://lore.kernel.org/r/SEYPR04MB64828A352836982C0184AA10FAD62@SEYPR04MB6482.apcprd04.prod.outlook.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Documentation/hwmon/index.rst
Documentation/hwmon/mp2891.rst [new file with mode: 0644]
MAINTAINERS
drivers/hwmon/pmbus/Kconfig
drivers/hwmon/pmbus/Makefile
drivers/hwmon/pmbus/mp2891.c [new file with mode: 0644]

index e92a3d5c7b59c577a9ea0fc5140f970dddbe569c..3b43a33547ae25980ab4d826ab749e83860b2dcf 100644 (file)
@@ -165,6 +165,7 @@ Hardware Monitoring Kernel Drivers
    mlxreg-fan
    mp2856
    mp2888
+   mp2891
    mp2975
    mp2993
    mp5023
diff --git a/Documentation/hwmon/mp2891.rst b/Documentation/hwmon/mp2891.rst
new file mode 100644 (file)
index 0000000..55944d1
--- /dev/null
@@ -0,0 +1,179 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Kernel driver mp2891
+====================
+
+Supported chips:
+
+  * MPS mp2891
+
+    Prefix: 'mp2891'
+
+  * Datasheet
+
+    Publicly available at the MPS website : https://www.monolithicpower.com/en/mp2891.html
+
+Author:
+
+       Noah Wang <noahwang.wang@outlook.com>
+
+Description
+-----------
+
+This driver implements support for Monolithic Power Systems, Inc. (MPS)
+MP2891 Multi-phase Digital VR Controller.
+
+Device compliant with:
+
+- PMBus rev 1.3 interface.
+
+Device supports direct and linear format for reading input voltage,
+output voltage, input current, output current, input power, output
+power, and temperature.
+
+The driver exports the following attributes via the 'sysfs' files
+for input voltage:
+
+**in1_input**
+
+**in1_label**
+
+**in1_crit**
+
+**in1_crit_alarm**
+
+**in1_lcrit**
+
+**in1_lcrit_alarm**
+
+**in1_min**
+
+**in1_min_alarm**
+
+The driver provides the following attributes for output voltage:
+
+**in2_input**
+
+**in2_label**
+
+**in2_crit**
+
+**in2_crit_alarm**
+
+**in2_lcrit**
+
+**in2_lcrit_alarm**
+
+**in2_min**
+
+**in2_min_alarm**
+
+**in3_input**
+
+**in3_label**
+
+**in3_crit**
+
+**in3_crit_alarm**
+
+**in3_lcrit**
+
+**in3_lcrit_alarm**
+
+**in3_min**
+
+**in3_min_alarm**
+
+The driver provides the following attributes for input current:
+
+**curr1_input**
+
+**curr1_label**
+
+**curr1_max**
+
+**curr1_max_alarm**
+
+**curr2_input**
+
+**curr2_label**
+
+**curr2_max**
+
+**curr2_max_alarm**
+
+The driver provides the following attributes for output current:
+
+**curr3_input**
+
+**curr3_label**
+
+**curr3_crit**
+
+**curr3_crit_alarm**
+
+**curr3_max**
+
+**curr3_max_alarm**
+
+**curr4_input**
+
+**curr4_label**
+
+**curr4_crit**
+
+**curr4_crit_alarm**
+
+**curr4_max**
+
+**curr4_max_alarm**
+
+The driver provides the following attributes for input power:
+
+**power1_input**
+
+**power1_label**
+
+**power1_max**
+
+**power1_alarm**
+
+**power2_input**
+
+**power2_label**
+
+**power2_max**
+
+**power2_alarm**
+
+The driver provides the following attributes for output power:
+
+**power3_input**
+
+**power3_label**
+
+**power4_input**
+
+**power4_label**
+
+The driver provides the following attributes for temperature:
+
+**temp1_input**
+
+**temp1_crit**
+
+**temp1_crit_alarm**
+
+**temp1_max**
+
+**temp1_max_alarm**
+
+**temp2_input**
+
+**temp2_crit**
+
+**temp2_crit_alarm**
+
+**temp2_max**
+
+**temp2_max_alarm**
index 9183321a9b3406c799544a03383cb5eae015f16d..516244c1cb2228332ee369c762c9206d30d17e4e 100644 (file)
@@ -15258,6 +15258,13 @@ S:     Maintained
 F:     Documentation/devicetree/bindings/leds/backlight/mps,mp3309c.yaml
 F:     drivers/video/backlight/mp3309c.c
 
+MPS MP2891 DRIVER
+M:     Noah Wang <noahwang.wang@outlook.com>
+L:     linux-hwmon@vger.kernel.org
+S:     Maintained
+F:     Documentation/hwmon/mp2891.rst
+F:     drivers/hwmon/pmbus/mp2891.c
+
 MPS MP2993 DRIVER
 M:     Noah Wang <noahwang.wang@outlook.com>
 L:     linux-hwmon@vger.kernel.org
index 7d32cfc1982011a83b6b0bd4c8fab84c421ba4bb..338b2e98dc225848f711cc52b5ebe43d38408907 100644 (file)
@@ -337,6 +337,15 @@ config SENSORS_MP2888
          This driver can also be built as a module. If so, the module will
          be called mp2888.
 
+config SENSORS_MP2891
+    tristate "MPS MP2891"
+    help
+      If you say yes here you get hardware monitoring support for MPS
+      MP2891 Dual Loop Digital Multi-Phase Controller.
+
+      This driver can also be built as a module. If so, the module will
+      be called mp2891.
+
 config SENSORS_MP2975
        tristate "MPS MP2975"
        help
index 6c7177fde3559a57ae8293b8abd3cb5330b2b03c..8afc5ba748f6d65cba6d94eff0e875d9e63025e8 100644 (file)
@@ -36,6 +36,7 @@ obj-$(CONFIG_SENSORS_MAX34440)        += max34440.o
 obj-$(CONFIG_SENSORS_MAX8688)  += max8688.o
 obj-$(CONFIG_SENSORS_MP2856)   += mp2856.o
 obj-$(CONFIG_SENSORS_MP2888)   += mp2888.o
+obj-$(CONFIG_SENSORS_MP2891)   += mp2891.o
 obj-$(CONFIG_SENSORS_MP2975)   += mp2975.o
 obj-$(CONFIG_SENSORS_MP2993)   += mp2993.o
 obj-$(CONFIG_SENSORS_MP5023)   += mp5023.o
diff --git a/drivers/hwmon/pmbus/mp2891.c b/drivers/hwmon/pmbus/mp2891.c
new file mode 100644 (file)
index 0000000..bb28b15
--- /dev/null
@@ -0,0 +1,600 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Hardware monitoring driver for MPS Multi-phase Digital VR Controllers(MP2891)
+ */
+
+#include <linux/bitfield.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include "pmbus.h"
+
+/*
+ * Vender specific registers, the register MFR_SVI3_IOUT_PRT(0x65),
+ * MFR_VOUT_LOOP_CTRL(0xBD), READ_PIN_EST(0x94)and READ_IIN_EST(0x95)
+ * redefine the standard PMBUS register. The MFR_SVI3_IOUT_PRT(0x65)
+ * is used to identify the iout scale and the MFR_VOUT_LOOP_CTRL(0xBD)
+ * is used to identify the vout scale. The READ_PIN_EST(0x94) is used
+ * to read input power per rail. The MP2891 does not have standard
+ * READ_IIN register(0x89), the iin telemetry can be obtained through
+ * the vendor redefined register READ_IIN_EST(0x95).
+ */
+#define MFR_VOUT_LOOP_CTRL     0xBD
+#define READ_PIN_EST   0x94
+#define READ_IIN_EST   0x95
+#define MFR_SVI3_IOUT_PRT      0x65
+
+#define MP2891_TEMP_LIMIT_OFFSET       40
+#define MP2891_PIN_LIMIT_UINT  2
+#define MP2891_IOUT_LIMIT_UINT 8
+#define MP2891_IOUT_SCALE_DIV  32
+#define MP2891_VOUT_SCALE_DIV  100
+#define MP2891_OVUV_DELTA_SCALE        50
+#define MP2891_OV_LIMIT_SCALE  20
+#define MP2891_UV_LIMIT_SCALE  5
+
+#define MP2891_PAGE_NUM        2
+
+#define MP2891_RAIL1_FUNC      (PMBUS_HAVE_VIN | PMBUS_HAVE_VOUT | \
+                                                       PMBUS_HAVE_IOUT | PMBUS_HAVE_TEMP | \
+                                                       PMBUS_HAVE_POUT | PMBUS_HAVE_PIN | \
+                                                       PMBUS_HAVE_IIN | PMBUS_HAVE_STATUS_VOUT | \
+                                                       PMBUS_HAVE_STATUS_IOUT | \
+                                                       PMBUS_HAVE_STATUS_INPUT | \
+                                                       PMBUS_HAVE_STATUS_TEMP)
+
+#define MP2891_RAIL2_FUNC      (PMBUS_HAVE_VOUT | PMBUS_HAVE_IOUT | \
+                                                       PMBUS_HAVE_TEMP | PMBUS_HAVE_POUT | \
+                                                       PMBUS_HAVE_PIN | PMBUS_HAVE_IIN | \
+                                                       PMBUS_HAVE_STATUS_VOUT | \
+                                                       PMBUS_HAVE_STATUS_IOUT | \
+                                                       PMBUS_HAVE_STATUS_INPUT | \
+                                                       PMBUS_HAVE_STATUS_TEMP)
+
+struct mp2891_data {
+       struct pmbus_driver_info info;
+       int vout_scale[MP2891_PAGE_NUM];
+       int iout_scale[MP2891_PAGE_NUM];
+};
+
+#define to_mp2891_data(x) container_of(x, struct mp2891_data, info)
+
+/* Converts a LINEAR11 value to DIRECT format */
+static u16 mp2891_reg2data_linear11(u16 word)
+{
+       s16 exponent;
+       s32 mantissa;
+       s64 val;
+
+       exponent = ((s16)word) >> 11;
+       mantissa = ((s16)((word & 0x7ff) << 5)) >> 5;
+       val = mantissa;
+
+       if (exponent >= 0)
+               val <<= exponent;
+       else
+               val >>= -exponent;
+
+       return val;
+}
+
+static int
+mp2891_identify_vout_scale(struct i2c_client *client, struct pmbus_driver_info *info,
+                          int page)
+{
+       struct mp2891_data *data = to_mp2891_data(info);
+       int ret;
+
+       ret = i2c_smbus_write_byte_data(client, PMBUS_PAGE, page);
+       if (ret < 0)
+               return ret;
+
+       ret = i2c_smbus_read_word_data(client, MFR_VOUT_LOOP_CTRL);
+       if (ret < 0)
+               return ret;
+
+       /*
+        * The output voltage is equal to the READ_VOUT(0x8B) register value multiplied
+        * by vout_scale.
+        * Obtain vout scale from the register MFR_VOUT_LOOP_CTRL, bits 15-14,bit 13.
+        * If MFR_VOUT_LOOP_CTRL[13] = 1, the vout scale is below:
+        * 2.5mV/LSB
+        * If MFR_VOUT_LOOP_CTRL[13] = 0, the vout scale is decided by
+        * MFR_VOUT_LOOP_CTRL[15:14]:
+        * 00b - 6.25mV/LSB, 01b - 5mV/LSB, 10b - 2mV/LSB, 11b - 1mV
+        */
+       if (ret & GENMASK(13, 13)) {
+               data->vout_scale[page] = 250;
+       } else {
+               ret = FIELD_GET(GENMASK(15, 14), ret);
+               if (ret == 0)
+                       data->vout_scale[page] = 625;
+               else if (ret == 1)
+                       data->vout_scale[page] = 500;
+               else if (ret == 2)
+                       data->vout_scale[page] = 200;
+               else
+                       data->vout_scale[page] = 100;
+       }
+
+       return 0;
+}
+
+static int
+mp2891_identify_iout_scale(struct i2c_client *client, struct pmbus_driver_info *info,
+                          int page)
+{
+       struct mp2891_data *data = to_mp2891_data(info);
+       int ret;
+
+       ret = i2c_smbus_write_byte_data(client, PMBUS_PAGE, page);
+       if (ret < 0)
+               return ret;
+
+       ret = i2c_smbus_read_word_data(client, MFR_SVI3_IOUT_PRT);
+       if (ret < 0)
+               return ret;
+
+       /*
+        * The output current is equal to the READ_IOUT(0x8C) register value
+        * multiplied by iout_scale.
+        * Obtain iout_scale from the register MFR_SVI3_IOUT_PRT[2:0].
+        * The value is selected as below:
+        * 000b - 1A/LSB, 001b - (1/32)A/LSB, 010b - (1/16)A/LSB,
+        * 011b - (1/8)A/LSB, 100b - (1/4)A/LSB, 101b - (1/2)A/LSB
+        * 110b - 1A/LSB, 111b - 2A/LSB
+        */
+       switch (ret & GENMASK(2, 0)) {
+       case 0:
+       case 6:
+               data->iout_scale[page] = 32;
+               break;
+       case 1:
+               data->iout_scale[page] = 1;
+               break;
+       case 2:
+               data->iout_scale[page] = 2;
+               break;
+       case 3:
+               data->iout_scale[page] = 4;
+               break;
+       case 4:
+               data->iout_scale[page] = 8;
+               break;
+       case 5:
+               data->iout_scale[page] = 16;
+               break;
+       default:
+               data->iout_scale[page] = 64;
+               break;
+       }
+
+       return 0;
+}
+
+static int mp2891_identify(struct i2c_client *client, struct pmbus_driver_info *info)
+{
+       int ret;
+
+       /* Identify vout scale for rail 1. */
+       ret = mp2891_identify_vout_scale(client, info, 0);
+       if (ret < 0)
+               return ret;
+
+       /* Identify vout scale for rail 2. */
+       ret = mp2891_identify_vout_scale(client, info, 1);
+       if (ret < 0)
+               return ret;
+
+       /* Identify iout scale for rail 1. */
+       ret = mp2891_identify_iout_scale(client, info, 0);
+       if (ret < 0)
+               return ret;
+
+       /* Identify iout scale for rail 2. */
+       return mp2891_identify_iout_scale(client, info, 1);
+}
+
+static int mp2891_read_byte_data(struct i2c_client *client, int page, int reg)
+{
+       int ret;
+
+       switch (reg) {
+       case PMBUS_VOUT_MODE:
+               /*
+                * The MP2891 does not follow standard PMBus protocol completely, the
+                * PMBUS_VOUT_MODE(0x20) in MP2891 is reserved and 0x00 is always
+                * returned when the register is read. But the calculation of vout in
+                * this driver is based on direct format. As a result, the format of
+                * vout is enforced to direct.
+                */
+               ret = PB_VOUT_MODE_DIRECT;
+               break;
+       default:
+               ret = -ENODATA;
+               break;
+       }
+
+       return ret;
+}
+
+static int mp2891_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 mp2891_data *data = to_mp2891_data(info);
+       int ret;
+
+       switch (reg) {
+       case PMBUS_READ_VIN:
+               ret = pmbus_read_word_data(client, page, phase, reg);
+               if (ret < 0)
+                       return ret;
+
+               ret = ret & GENMASK(9, 0);
+               break;
+       case PMBUS_READ_IIN:
+               /*
+                * The MP2891 does not have standard PMBUS_READ_IIN register(0x89),
+                * the iin telemetry can be obtained through the vender redefined
+                * register READ_IIN_EST(0x95). The MP2891 PMBUS_READ_IIN register
+                * is linear11 format, But the pout scale is set to 1A/Lsb(using
+                * r/m/b scale). As a result, the iin read from MP2891 should be
+                * calculated to A, then return the result to pmbus core.
+                */
+               ret = pmbus_read_word_data(client, page, phase, READ_IIN_EST);
+               if (ret < 0)
+                       return ret;
+
+               ret = mp2891_reg2data_linear11(ret);
+               break;
+       case PMBUS_READ_PIN:
+               /*
+                * The MP2891 has standard PMBUS_READ_PIN register(0x97), but this
+                * is not used to read the input power per rail. The input power
+                * per rail is read through the vender redefined register
+                * READ_PIN_EST(0x94). The MP2891 PMBUS_READ_PIN register is linear11
+                * format, But the pout scale is set to 1W/Lsb(using r/m/b scale).
+                * As a result, the pin read from MP2891 should be calculated to W,
+                * then return the result to pmbus core.
+                */
+               ret = pmbus_read_word_data(client, page, phase, READ_PIN_EST);
+               if (ret < 0)
+                       return ret;
+
+               ret = mp2891_reg2data_linear11(ret);
+               break;
+       case PMBUS_READ_POUT:
+               /*
+                * The MP2891 PMBUS_READ_POUT register is linear11 format, and the
+                * exponent is not a constant value. But the pout scale is set to
+                * 1W/Lsb(using r/m/b scale). As a result, the pout read from MP2891
+                * should be calculated to W, then return the result to pmbus core.
+                */
+               ret = pmbus_read_word_data(client, page, phase, reg);
+               if (ret < 0)
+                       return ret;
+
+               ret = mp2891_reg2data_linear11(ret);
+               break;
+       case PMBUS_READ_VOUT:
+       case PMBUS_VOUT_UV_WARN_LIMIT:
+               ret = pmbus_read_word_data(client, page, phase, reg);
+               if (ret < 0)
+                       return ret;
+
+               ret = DIV_ROUND_CLOSEST(ret * data->vout_scale[page], MP2891_VOUT_SCALE_DIV);
+               break;
+       case PMBUS_READ_IOUT:
+               ret = pmbus_read_word_data(client, page, phase, reg);
+               if (ret < 0)
+                       return ret;
+
+               ret = DIV_ROUND_CLOSEST((ret & GENMASK(10, 0)) * data->iout_scale[page],
+                                       MP2891_IOUT_SCALE_DIV);
+               break;
+       case PMBUS_OT_FAULT_LIMIT:
+       case PMBUS_OT_WARN_LIMIT:
+               /*
+                * The scale of MP2891 PMBUS_OT_FAULT_LIMIT and PMBUS_OT_WARN_LIMIT
+                * is 1°C/LSB and they have 40°C offset.
+                */
+               ret = pmbus_read_word_data(client, page, phase, reg);
+               if (ret < 0)
+                       return ret;
+
+               ret = (ret & GENMASK(7, 0)) - MP2891_TEMP_LIMIT_OFFSET;
+               break;
+       case PMBUS_VIN_OV_FAULT_LIMIT:
+               /*
+                * The MP2891 PMBUS_VIN_OV_FAULT_LIMIT scale is 125mV/Lsb.
+                * but the vin scale is set to 31.25mV/Lsb(using r/m/b scale).
+                * As a result, the limit value should be multiplied by 4.
+                */
+               ret = pmbus_read_word_data(client, page, phase, reg);
+               if (ret < 0)
+                       return ret;
+
+               ret = (ret & GENMASK(7, 0)) * 4;
+               break;
+       case PMBUS_VOUT_UV_FAULT_LIMIT:
+               ret = pmbus_read_word_data(client, page, phase, reg);
+               if (ret < 0)
+                       return ret;
+
+               if (FIELD_GET(GENMASK(11, 8), ret))
+                       ret = FIELD_GET(GENMASK(7, 0), ret) * MP2891_UV_LIMIT_SCALE -
+                               (FIELD_GET(GENMASK(11, 8), ret) + 1) * MP2891_OVUV_DELTA_SCALE;
+               else
+                       ret = FIELD_GET(GENMASK(7, 0), ret) * MP2891_UV_LIMIT_SCALE;
+
+               ret = ret < 0 ? 0 : ret;
+               break;
+       case PMBUS_VOUT_OV_FAULT_LIMIT:
+               ret = pmbus_read_word_data(client, page, phase, reg);
+               if (ret < 0)
+                       return ret;
+
+               if (FIELD_GET(GENMASK(11, 8), ret))
+                       ret = FIELD_GET(GENMASK(7, 0), ret) * MP2891_OV_LIMIT_SCALE +
+                               (FIELD_GET(GENMASK(11, 8), ret) + 1) * MP2891_OVUV_DELTA_SCALE;
+               else
+                       ret = FIELD_GET(GENMASK(7, 0), ret) * MP2891_OV_LIMIT_SCALE;
+               break;
+       case PMBUS_IOUT_OC_WARN_LIMIT:
+       case PMBUS_IOUT_OC_FAULT_LIMIT:
+               ret = pmbus_read_word_data(client, page, phase, reg);
+               if (ret < 0)
+                       return ret;
+
+               ret = DIV_ROUND_CLOSEST((ret & GENMASK(7, 0)) * data->iout_scale[page] *
+                                               MP2891_IOUT_LIMIT_UINT, MP2891_IOUT_SCALE_DIV);
+               break;
+       case PMBUS_IIN_OC_WARN_LIMIT:
+               /*
+                * The scale of PMBUS_IIN_OC_WARN_LIMIT is 0.5A/Lsb, but the iin scale
+                * is set to 1A/Lsb(using r/m/b scale), so the word data should be
+                * divided by 2.
+                */
+               ret = pmbus_read_word_data(client, 0, phase, reg);
+               if (ret < 0)
+                       return ret;
+
+               ret = DIV_ROUND_CLOSEST((ret & GENMASK(9, 0)), 2);
+               break;
+       case PMBUS_PIN_OP_WARN_LIMIT:
+               /*
+                * The scale of PMBUS_PIN_OP_WARN_LIMIT is 2W/Lsb, but the pin scale
+                * is set to 1W/Lsb(using r/m/b scale), so the word data should be
+                * multiplied by 2.
+                */
+               ret = pmbus_read_word_data(client, 0, phase, reg);
+               if (ret < 0)
+                       return ret;
+
+               ret = (ret & GENMASK(9, 0)) * MP2891_PIN_LIMIT_UINT;
+               break;
+       case PMBUS_READ_TEMPERATURE_1:
+       case PMBUS_VIN_UV_FAULT_LIMIT:
+       case PMBUS_VIN_UV_WARN_LIMIT:
+               ret = -ENODATA;
+               break;
+       default:
+               ret = -EINVAL;
+               break;
+       }
+
+       return ret;
+}
+
+static int mp2891_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 mp2891_data *data = to_mp2891_data(info);
+       int ret;
+
+       switch (reg) {
+       case PMBUS_VOUT_UV_WARN_LIMIT:
+               ret = pmbus_write_word_data(client, page, reg,
+                                           DIV_ROUND_CLOSEST(word * MP2891_VOUT_SCALE_DIV,
+                                                             data->vout_scale[page]));
+               break;
+       case PMBUS_VOUT_UV_FAULT_LIMIT:
+               /*
+                * The PMBUS_VOUT_UV_FAULT_LIMIT[7:0] is the limit value, and bit8-bit15
+                * should not be changed.
+                */
+               ret = pmbus_read_word_data(client, page, 0xff, reg);
+               if (ret < 0)
+                       return ret;
+
+               if (FIELD_GET(GENMASK(11, 8), ret))
+                       ret = pmbus_write_word_data(client, page, reg,
+                                                   (ret & ~GENMASK(7, 0)) |
+                                                       FIELD_PREP(GENMASK(7, 0),
+                                                                  DIV_ROUND_CLOSEST(word +
+                                                       (FIELD_GET(GENMASK(11, 8), ret) + 1) *
+                                                               MP2891_OVUV_DELTA_SCALE,
+                                                               MP2891_UV_LIMIT_SCALE)));
+               else
+                       ret = pmbus_write_word_data(client, page, reg,
+                                                   (ret & ~GENMASK(7, 0)) |
+                                       FIELD_PREP(GENMASK(7, 0),
+                                                  DIV_ROUND_CLOSEST(word,
+                                                                    MP2891_UV_LIMIT_SCALE)));
+               break;
+       case PMBUS_VOUT_OV_FAULT_LIMIT:
+               /*
+                * The PMBUS_VOUT_OV_FAULT_LIMIT[7:0] is the limit value, and bit8-bit15
+                * should not be changed.
+                */
+               ret = pmbus_read_word_data(client, page, 0xff, reg);
+               if (ret < 0)
+                       return ret;
+
+               if (FIELD_GET(GENMASK(11, 8), ret))
+                       ret = pmbus_write_word_data(client, page, reg,
+                                                   (ret & ~GENMASK(7, 0)) |
+                                                       FIELD_PREP(GENMASK(7, 0),
+                                                                  DIV_ROUND_CLOSEST(word -
+                                                       (FIELD_GET(GENMASK(11, 8), ret) + 1) *
+                                                               MP2891_OVUV_DELTA_SCALE,
+                                                               MP2891_OV_LIMIT_SCALE)));
+               else
+                       ret = pmbus_write_word_data(client, page, reg,
+                                                   (ret & ~GENMASK(7, 0)) |
+                                       FIELD_PREP(GENMASK(7, 0),
+                                                  DIV_ROUND_CLOSEST(word,
+                                                                    MP2891_OV_LIMIT_SCALE)));
+               break;
+       case PMBUS_VIN_OV_FAULT_LIMIT:
+               /*
+                * The PMBUS_VIN_OV_FAULT_LIMIT[7:0] is the limit value, and bit8-bit15
+                * should not be changed. The scale of PMBUS_VIN_OV_FAULT_LIMIT is 125mV/Lsb,
+                * but the vin scale is set to 31.25mV/Lsb(using r/m/b scale), so the word data
+                * should be divided by 4.
+                */
+               ret = pmbus_read_word_data(client, page, 0xff, reg);
+               if (ret < 0)
+                       return ret;
+
+               ret = pmbus_write_word_data(client, page, reg,
+                                           (ret & ~GENMASK(7, 0)) |
+                                               FIELD_PREP(GENMASK(7, 0),
+                                                          DIV_ROUND_CLOSEST(word, 4)));
+               break;
+       case PMBUS_OT_FAULT_LIMIT:
+       case PMBUS_OT_WARN_LIMIT:
+               /*
+                * The scale of MP2891 PMBUS_OT_FAULT_LIMIT and PMBUS_OT_WARN_LIMIT
+                * have 40°C offset. The bit0-bit7 is the limit value, and bit8-bit15
+                * should not be changed.
+                */
+               ret = pmbus_read_word_data(client, page, 0xff, reg);
+               if (ret < 0)
+                       return ret;
+
+               ret = pmbus_write_word_data(client, page, reg,
+                                           (ret & ~GENMASK(7, 0)) |
+                               FIELD_PREP(GENMASK(7, 0), word + MP2891_TEMP_LIMIT_OFFSET));
+               break;
+       case PMBUS_IOUT_OC_WARN_LIMIT:
+       case PMBUS_IOUT_OC_FAULT_LIMIT:
+               ret = pmbus_write_word_data(client, page, reg,
+                                           DIV_ROUND_CLOSEST(word * MP2891_IOUT_SCALE_DIV,
+                                                             MP2891_IOUT_LIMIT_UINT *
+                                                                 data->iout_scale[page]));
+               break;
+       case PMBUS_IIN_OC_WARN_LIMIT:
+               /*
+                * The scale of PMBUS_IIN_OC_WARN_LIMIT is 0.5A/Lsb, but the iin scale
+                * is set to 1A/Lsb(using r/m/b scale), so the word data should be
+                * multiplied by 2.
+                */
+               ret = pmbus_write_word_data(client, page, reg, word * 2);
+               break;
+       case PMBUS_PIN_OP_WARN_LIMIT:
+               /*
+                * The scale of PMBUS_PIN_OP_WARN_LIMIT is 2W/Lsb, but the pin scale
+                * is set to 1W/Lsb(using r/m/b scale), so the word data should be
+                * divided by 2.
+                */
+               ret = pmbus_write_word_data(client, page, reg,
+                                           DIV_ROUND_CLOSEST(word, MP2891_PIN_LIMIT_UINT));
+               break;
+       case PMBUS_VIN_UV_FAULT_LIMIT:
+       case PMBUS_VIN_UV_WARN_LIMIT:
+               ret = -ENODATA;
+               break;
+       default:
+               ret = -EINVAL;
+               break;
+       }
+
+       return ret;
+}
+
+static const struct pmbus_driver_info mp2891_info = {
+       .pages = MP2891_PAGE_NUM,
+       .format[PSC_VOLTAGE_IN] = direct,
+       .format[PSC_CURRENT_IN] = direct,
+       .format[PSC_CURRENT_OUT] = direct,
+       .format[PSC_TEMPERATURE] = direct,
+       .format[PSC_POWER] = direct,
+       .format[PSC_VOLTAGE_OUT] = direct,
+
+       /* set vin scale 31.25mV/Lsb */
+       .m[PSC_VOLTAGE_IN] = 32,
+       .R[PSC_VOLTAGE_IN] = 0,
+       .b[PSC_VOLTAGE_IN] = 0,
+
+       /* set temp scale 1000m°C/Lsb */
+       .m[PSC_TEMPERATURE] = 1,
+       .R[PSC_TEMPERATURE] = 0,
+       .b[PSC_TEMPERATURE] = 0,
+
+       .m[PSC_CURRENT_IN] = 1,
+       .R[PSC_CURRENT_IN] = 0,
+       .b[PSC_CURRENT_IN] = 0,
+
+       .m[PSC_CURRENT_OUT] = 1,
+       .R[PSC_CURRENT_OUT] = 0,
+       .b[PSC_CURRENT_OUT] = 0,
+
+       .m[PSC_POWER] = 1,
+       .R[PSC_POWER] = 0,
+       .b[PSC_POWER] = 0,
+
+       .m[PSC_VOLTAGE_OUT] = 1,
+       .R[PSC_VOLTAGE_OUT] = 3,
+       .b[PSC_VOLTAGE_OUT] = 0,
+
+       .func[0] = MP2891_RAIL1_FUNC,
+       .func[1] = MP2891_RAIL2_FUNC,
+       .read_word_data = mp2891_read_word_data,
+       .write_word_data = mp2891_write_word_data,
+       .read_byte_data = mp2891_read_byte_data,
+       .identify = mp2891_identify,
+};
+
+static int mp2891_probe(struct i2c_client *client)
+{
+       struct mp2891_data *data;
+
+       data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
+       if (!data)
+               return -ENOMEM;
+
+       memcpy(&data->info, &mp2891_info, sizeof(mp2891_info));
+
+       return pmbus_do_probe(client, &data->info);
+}
+
+static const struct i2c_device_id mp2891_id[] = {
+       {"mp2891", 0},
+       {}
+};
+MODULE_DEVICE_TABLE(i2c, mp2891_id);
+
+static const struct of_device_id __maybe_unused mp2891_of_match[] = {
+       {.compatible = "mps,mp2891"},
+       {}
+};
+MODULE_DEVICE_TABLE(of, mp2891_of_match);
+
+static struct i2c_driver mp2891_driver = {
+       .driver = {
+               .name = "mp2891",
+               .of_match_table = mp2891_of_match,
+       },
+       .probe = mp2891_probe,
+       .id_table = mp2891_id,
+};
+
+module_i2c_driver(mp2891_driver);
+
+MODULE_AUTHOR("Noah Wang <noahwang.wang@outlook.com>");
+MODULE_DESCRIPTION("PMBus driver for MPS MP2891");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(PMBUS);