This is done to support other functionality provided by the SBRMI, which
does not fit in the hwmon subsystem.
- Move the SBRMI core functionality and I2C device probing part to misc.
- Move hwmon device sensor to misc as only power is reported through
hwmon sensor.
Signed-off-by: Akshay Gupta <akshay.gupta@xxxxxxx>
Reviewed-by: Naveen Krishna Chatradhi <naveenkrishna.chatradhi@xxxxxxx>
---
Changes since v1:
- File name update
- Add hwmon sensor registration in this patch
- Update Copyright year
drivers/hwmon/Kconfig | 10 -
drivers/hwmon/sbrmi.c | 357 -------------------------------
drivers/misc/Kconfig | 1 +
drivers/misc/Makefile | 1 +
drivers/misc/amd-sbi/Kconfig | 9 +
drivers/misc/amd-sbi/Makefile | 3 +
drivers/misc/amd-sbi/rmi-core.c | 115 ++++++++++
drivers/misc/amd-sbi/rmi-core.h | 65 ++++++
drivers/misc/amd-sbi/rmi-hwmon.c | 121 +++++++++++
drivers/misc/amd-sbi/rmi-i2c.c | 111 ++++++++++
10 files changed, 426 insertions(+), 367 deletions(-)
delete mode 100644 drivers/hwmon/sbrmi.c
create mode 100644 drivers/misc/amd-sbi/Kconfig
create mode 100644 drivers/misc/amd-sbi/Makefile
create mode 100644 drivers/misc/amd-sbi/rmi-core.c
create mode 100644 drivers/misc/amd-sbi/rmi-core.h
create mode 100644 drivers/misc/amd-sbi/rmi-hwmon.c
create mode 100644 drivers/misc/amd-sbi/rmi-i2c.c
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index e14ae18a973b..bfdb7a91c803 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -1836,16 +1836,6 @@ config SENSORS_SBTSI
This driver can also be built as a module. If so, the module will
be called sbtsi_temp.
-config SENSORS_SBRMI
- tristate "Emulated SB-RMI sensor"
- depends on I2C
- help
- If you say yes here you get support for emulated RMI
- sensors on AMD SoCs with APML interface connected to a BMC device.
-
- This driver can also be built as a module. If so, the module will
- be called sbrmi.
-
config SENSORS_SHT15
tristate "Sensiron humidity and temperature sensors. SHT15 and compat."
depends on GPIOLIB || COMPILE_TEST
diff --git a/drivers/hwmon/sbrmi.c b/drivers/hwmon/sbrmi.c
deleted file mode 100644
index d48d8e5460ff..000000000000
--- a/drivers/hwmon/sbrmi.c
+++ /dev/null
@@ -1,357 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-or-later
-/*
- * sbrmi.c - hwmon driver for a SB-RMI mailbox
- * compliant AMD SoC device.
- *
- * Copyright (C) 2020-2021 Advanced Micro Devices, Inc.
- */
-
-#include <linux/delay.h>
-#include <linux/err.h>
-#include <linux/hwmon.h>
-#include <linux/i2c.h>
-#include <linux/init.h>
-#include <linux/module.h>
-#include <linux/mutex.h>
-#include <linux/of.h>
-
-/* Do not allow setting negative power limit */
-#define SBRMI_PWR_MIN 0
-/* Mask for Status Register bit[1] */
-#define SW_ALERT_MASK 0x2
-
-/* Software Interrupt for triggering */
-#define START_CMD 0x80
-#define TRIGGER_MAILBOX 0x01
-
-/*
- * SB-RMI supports soft mailbox service request to MP1 (power management
- * firmware) through SBRMI inbound/outbound message registers.
- * SB-RMI message IDs
- */
-enum sbrmi_msg_id {
- SBRMI_READ_PKG_PWR_CONSUMPTION = 0x1,
- SBRMI_WRITE_PKG_PWR_LIMIT,
- SBRMI_READ_PKG_PWR_LIMIT,
- SBRMI_READ_PKG_MAX_PWR_LIMIT,
-};
-
-/* SB-RMI registers */
-enum sbrmi_reg {
- SBRMI_CTRL = 0x01,
- SBRMI_STATUS,
- SBRMI_OUTBNDMSG0 = 0x30,
- SBRMI_OUTBNDMSG1,
- SBRMI_OUTBNDMSG2,
- SBRMI_OUTBNDMSG3,
- SBRMI_OUTBNDMSG4,
- SBRMI_OUTBNDMSG5,
- SBRMI_OUTBNDMSG6,
- SBRMI_OUTBNDMSG7,
- SBRMI_INBNDMSG0,
- SBRMI_INBNDMSG1,
- SBRMI_INBNDMSG2,
- SBRMI_INBNDMSG3,
- SBRMI_INBNDMSG4,
- SBRMI_INBNDMSG5,
- SBRMI_INBNDMSG6,
- SBRMI_INBNDMSG7,
- SBRMI_SW_INTERRUPT,
-};
-
-/* Each client has this additional data */
-struct sbrmi_data {
- struct i2c_client *client;
- struct mutex lock;
- u32 pwr_limit_max;
-};
-
-struct sbrmi_mailbox_msg {
- u8 cmd;
- bool read;
- u32 data_in;
- u32 data_out;
-};
-
-static int sbrmi_enable_alert(struct i2c_client *client)
-{
- int ctrl;
-
- /*
- * Enable the SB-RMI Software alert status
- * by writing 0 to bit 4 of Control register(0x1)
- */
- ctrl = i2c_smbus_read_byte_data(client, SBRMI_CTRL);
- if (ctrl < 0)
- return ctrl;
-
- if (ctrl & 0x10) {
- ctrl &= ~0x10;
- return i2c_smbus_write_byte_data(client,
- SBRMI_CTRL, ctrl);
- }
-
- return 0;
-}
-
-static int rmi_mailbox_xfer(struct sbrmi_data *data,
- struct sbrmi_mailbox_msg *msg)
-{
- int i, ret, retry = 10;
- int sw_status;
- u8 byte;
-
- mutex_lock(&data->lock);
-
- /* Indicate firmware a command is to be serviced */
- ret = i2c_smbus_write_byte_data(data->client,
- SBRMI_INBNDMSG7, START_CMD);
- if (ret < 0)
- goto exit_unlock;
-
- /* Write the command to SBRMI::InBndMsg_inst0 */
- ret = i2c_smbus_write_byte_data(data->client,
- SBRMI_INBNDMSG0, msg->cmd);
- if (ret < 0)
- goto exit_unlock;
-
- /*
- * For both read and write the initiator (BMC) writes
- * Command Data In[31:0] to SBRMI::InBndMsg_inst[4:1]
- * SBRMI_x3C(MSB):SBRMI_x39(LSB)
- */
- for (i = 0; i < 4; i++) {
- byte = (msg->data_in >> i * 8) & 0xff;
- ret = i2c_smbus_write_byte_data(data->client,
- SBRMI_INBNDMSG1 + i, byte);
- if (ret < 0)
- goto exit_unlock;
- }
-
- /*
- * Write 0x01 to SBRMI::SoftwareInterrupt to notify firmware to
- * perform the requested read or write command
- */
- ret = i2c_smbus_write_byte_data(data->client,
- SBRMI_SW_INTERRUPT, TRIGGER_MAILBOX);
- if (ret < 0)
- goto exit_unlock;
-
- /*
- * Firmware will write SBRMI::Status[SwAlertSts]=1 to generate
- * an ALERT (if enabled) to initiator (BMC) to indicate completion
- * of the requested command
- */
- do {
- sw_status = i2c_smbus_read_byte_data(data->client,
- SBRMI_STATUS);
- if (sw_status < 0) {
- ret = sw_status;
- goto exit_unlock;
- }
- if (sw_status & SW_ALERT_MASK)
- break;
- usleep_range(50, 100);
- } while (retry--);
-
- if (retry < 0) {
- dev_err(&data->client->dev,
- "Firmware fail to indicate command completion\n");
- ret = -EIO;
- goto exit_unlock;
- }
-
- /*
- * For a read operation, the initiator (BMC) reads the firmware
- * response Command Data Out[31:0] from SBRMI::OutBndMsg_inst[4:1]
- * {SBRMI_x34(MSB):SBRMI_x31(LSB)}.
- */
- if (msg->read) {
- for (i = 0; i < 4; i++) {
- ret = i2c_smbus_read_byte_data(data->client,
- SBRMI_OUTBNDMSG1 + i);
- if (ret < 0)
- goto exit_unlock;
- msg->data_out |= ret << i * 8;
- }
- }
-
- /*
- * BMC must write 1'b1 to SBRMI::Status[SwAlertSts] to clear the
- * ALERT to initiator
- */
- ret = i2c_smbus_write_byte_data(data->client, SBRMI_STATUS,
- sw_status | SW_ALERT_MASK);
-
-exit_unlock:
- mutex_unlock(&data->lock);
- return ret;
-}
-
-static int sbrmi_read(struct device *dev, enum hwmon_sensor_types type,
- u32 attr, int channel, long *val)
-{
- struct sbrmi_data *data = dev_get_drvdata(dev);
- struct sbrmi_mailbox_msg msg = { 0 };
- int ret;
-
- if (type != hwmon_power)
- return -EINVAL;
-
- msg.read = true;
- switch (attr) {
- case hwmon_power_input:
- msg.cmd = SBRMI_READ_PKG_PWR_CONSUMPTION;
- ret = rmi_mailbox_xfer(data, &msg);
- break;
- case hwmon_power_cap:
- msg.cmd = SBRMI_READ_PKG_PWR_LIMIT;
- ret = rmi_mailbox_xfer(data, &msg);
- break;
- case hwmon_power_cap_max:
- msg.data_out = data->pwr_limit_max;
- ret = 0;
- break;
- default:
- return -EINVAL;
- }
- if (ret < 0)
- return ret;
- /* hwmon power attributes are in microWatt */
- *val = (long)msg.data_out * 1000;
- return ret;
-}
-
-static int sbrmi_write(struct device *dev, enum hwmon_sensor_types type,
- u32 attr, int channel, long val)
-{
- struct sbrmi_data *data = dev_get_drvdata(dev);
- struct sbrmi_mailbox_msg msg = { 0 };
-
- if (type != hwmon_power && attr != hwmon_power_cap)
- return -EINVAL;
- /*
- * hwmon power attributes are in microWatt
- * mailbox read/write is in mWatt
- */
- val /= 1000;
-
- val = clamp_val(val, SBRMI_PWR_MIN, data->pwr_limit_max);
-
- msg.cmd = SBRMI_WRITE_PKG_PWR_LIMIT;
- msg.data_in = val;
- msg.read = false;
-
- return rmi_mailbox_xfer(data, &msg);
-}
-
-static umode_t sbrmi_is_visible(const void *data,
- enum hwmon_sensor_types type,
- u32 attr, int channel)
-{
- switch (type) {
- case hwmon_power:
- switch (attr) {
- case hwmon_power_input:
- case hwmon_power_cap_max:
- return 0444;
- case hwmon_power_cap:
- return 0644;
- }
- break;
- default:
- break;
- }
- return 0;
-}
-
-static const struct hwmon_channel_info * const sbrmi_info[] = {
- HWMON_CHANNEL_INFO(power,
- HWMON_P_INPUT | HWMON_P_CAP | HWMON_P_CAP_MAX),
- NULL
-};
-
-static const struct hwmon_ops sbrmi_hwmon_ops = {
- .is_visible = sbrmi_is_visible,
- .read = sbrmi_read,
- .write = sbrmi_write,
-};
-
-static const struct hwmon_chip_info sbrmi_chip_info = {
- .ops = &sbrmi_hwmon_ops,
- .info = sbrmi_info,
-};
-
-static int sbrmi_get_max_pwr_limit(struct sbrmi_data *data)
-{
- struct sbrmi_mailbox_msg msg = { 0 };
- int ret;
-
- msg.cmd = SBRMI_READ_PKG_MAX_PWR_LIMIT;
- msg.read = true;
- ret = rmi_mailbox_xfer(data, &msg);
- if (ret < 0)
- return ret;
- data->pwr_limit_max = msg.data_out;
-
- return ret;
-}
-
-static int sbrmi_probe(struct i2c_client *client)
-{
- struct device *dev = &client->dev;
- struct device *hwmon_dev;
- struct sbrmi_data *data;
- int ret;
-
- data = devm_kzalloc(dev, sizeof(struct sbrmi_data), GFP_KERNEL);
- if (!data)
- return -ENOMEM;
-
- data->client = client;
- mutex_init(&data->lock);
-
- /* Enable alert for SB-RMI sequence */
- ret = sbrmi_enable_alert(client);
- if (ret < 0)
- return ret;
-
- /* Cache maximum power limit */
- ret = sbrmi_get_max_pwr_limit(data);
- if (ret < 0)
- return ret;
-
- hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, data,
- &sbrmi_chip_info, NULL);
-
- return PTR_ERR_OR_ZERO(hwmon_dev);
-}
-
-static const struct i2c_device_id sbrmi_id[] = {
- {"sbrmi"},
- {}
-};
-MODULE_DEVICE_TABLE(i2c, sbrmi_id);
-
-static const struct of_device_id __maybe_unused sbrmi_of_match[] = {
- {
- .compatible = "amd,sbrmi",
- },
- { },
-};
-MODULE_DEVICE_TABLE(of, sbrmi_of_match);
-
-static struct i2c_driver sbrmi_driver = {
- .driver = {
- .name = "sbrmi",
- .of_match_table = of_match_ptr(sbrmi_of_match),
- },
- .probe = sbrmi_probe,
- .id_table = sbrmi_id,
-};
-
-module_i2c_driver(sbrmi_driver);
-
-MODULE_AUTHOR("Akshay Gupta <akshay.gupta@xxxxxxx>");
-MODULE_DESCRIPTION("Hwmon driver for AMD SB-RMI emulated sensor");
-MODULE_LICENSE("GPL");
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index faf983680040..1bb74da980f7 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -602,4 +602,5 @@ source "drivers/misc/cardreader/Kconfig"
source "drivers/misc/uacce/Kconfig"
source "drivers/misc/pvpanic/Kconfig"
source "drivers/misc/mchp_pci1xxxx/Kconfig"
+source "drivers/misc/amd-sbi/Kconfig"
endmenu
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index 153a3f4837e8..2edf1d7ceac8 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -69,3 +69,4 @@ obj-$(CONFIG_TMR_INJECT) += xilinx_tmr_inject.o
obj-$(CONFIG_TPS6594_ESM) += tps6594-esm.o
obj-$(CONFIG_TPS6594_PFSM) += tps6594-pfsm.o
obj-$(CONFIG_NSM) += nsm.o
+obj-y += amd-sbi/
diff --git a/drivers/misc/amd-sbi/Kconfig b/drivers/misc/amd-sbi/Kconfig
new file mode 100644
index 000000000000..be2d9e495eb7
--- /dev/null
+++ b/drivers/misc/amd-sbi/Kconfig
@@ -0,0 +1,9 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config AMD_SBRMI_I2C
+ tristate "AMD side band RMI support"
+ depends on I2C
+ help
+ Side band RMI over I2C support for AMD out of band management.
+
+ This driver can also be built as a module. If so, the module will
+ be called sbrmi-i2c.
diff --git a/drivers/misc/amd-sbi/Makefile b/drivers/misc/amd-sbi/Makefile
new file mode 100644
index 000000000000..eac90a7635de
--- /dev/null
+++ b/drivers/misc/amd-sbi/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0-only
+sbrmi-i2c-objs := rmi-i2c.o rmi-core.o rmi-hwmon.o
+obj-$(CONFIG_AMD_SBRMI_I2C) += sbrmi-i2c.o
diff --git a/drivers/misc/amd-sbi/rmi-core.c b/drivers/misc/amd-sbi/rmi-core.c
new file mode 100644
index 000000000000..5d93fb703fa0
--- /dev/null
+++ b/drivers/misc/amd-sbi/rmi-core.c
@@ -0,0 +1,115 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * sbrmi-core.c - file defining SB-RMI protocols compliant
+ * AMD SoC device.
+ *
+ * Copyright (C) 2024 Advanced Micro Devices, Inc.
+ */
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/mutex.h>
+#include "rmi-core.h"
+
+/* Mask for Status Register bit[1] */
+#define SW_ALERT_MASK 0x2
+/* Do not allow setting negative power limit */
+#define SBRMI_PWR_MIN 0
+
+/* Software Interrupt for triggering */
+#define START_CMD 0x80
+#define TRIGGER_MAILBOX 0x01
+
+int rmi_mailbox_xfer(struct sbrmi_data *data,
+ struct sbrmi_mailbox_msg *msg)
+{
+ int i, ret, retry = 10;
+ int sw_status;
+ u8 byte;
+
+ mutex_lock(&data->lock);
+
+ /* Indicate firmware a command is to be serviced */
+ ret = i2c_smbus_write_byte_data(data->client,
+ SBRMI_INBNDMSG7, START_CMD);
+ if (ret < 0)
+ goto exit_unlock;
+
+ /* Write the command to SBRMI::InBndMsg_inst0 */
+ ret = i2c_smbus_write_byte_data(data->client,
+ SBRMI_INBNDMSG0, msg->cmd);
+ if (ret < 0)
+ goto exit_unlock;
+
+ /*
+ * For both read and write the initiator (BMC) writes
+ * Command Data In[31:0] to SBRMI::InBndMsg_inst[4:1]
+ * SBRMI_x3C(MSB):SBRMI_x39(LSB)
+ */
+ for (i = 0; i < 4; i++) {
+ byte = (msg->data_in >> i * 8) & 0xff;
+ ret = i2c_smbus_write_byte_data(data->client,
+ SBRMI_INBNDMSG1 + i, byte);
+ if (ret < 0)
+ goto exit_unlock;
+ }
+
+ /*
+ * Write 0x01 to SBRMI::SoftwareInterrupt to notify firmware to
+ * perform the requested read or write command
+ */
+ ret = i2c_smbus_write_byte_data(data->client,
+ SBRMI_SW_INTERRUPT, TRIGGER_MAILBOX);
+ if (ret < 0)
+ goto exit_unlock;
+
+ /*
+ * Firmware will write SBRMI::Status[SwAlertSts]=1 to generate
+ * an ALERT (if enabled) to initiator (BMC) to indicate completion
+ * of the requested command
+ */
+ do {
+ sw_status = i2c_smbus_read_byte_data(data->client,
+ SBRMI_STATUS);
+ if (sw_status < 0) {
+ ret = sw_status;
+ goto exit_unlock;
+ }
+ if (sw_status & SW_ALERT_MASK)
+ break;
+ usleep_range(50, 100);
+ } while (retry--);
+
+ if (retry < 0) {
+ dev_err(&data->client->dev,
+ "Firmware fail to indicate command completion\n");
+ ret = -EIO;
+ goto exit_unlock;
+ }
+
+ /*
+ * For a read operation, the initiator (BMC) reads the firmware
+ * response Command Data Out[31:0] from SBRMI::OutBndMsg_inst[4:1]
+ * {SBRMI_x34(MSB):SBRMI_x31(LSB)}.
+ */
+ if (msg->read) {
+ for (i = 0; i < 4; i++) {
+ ret = i2c_smbus_read_byte_data(data->client,
+ SBRMI_OUTBNDMSG1 + i);
+ if (ret < 0)
+ goto exit_unlock;
+ msg->data_out |= ret << i * 8;
+ }
+ }
+
+ /*
+ * BMC must write 1'b1 to SBRMI::Status[SwAlertSts] to clear the
+ * ALERT to initiator
+ */
+ ret = i2c_smbus_write_byte_data(data->client, SBRMI_STATUS,
+ sw_status | SW_ALERT_MASK);
+
+exit_unlock:
+ mutex_unlock(&data->lock);
+ return ret;
+}
diff --git a/drivers/misc/amd-sbi/rmi-core.h b/drivers/misc/amd-sbi/rmi-core.h
new file mode 100644
index 000000000000..3d600e450e08
--- /dev/null
+++ b/drivers/misc/amd-sbi/rmi-core.h
@@ -0,0 +1,65 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2024 Advanced Micro Devices, Inc.
+ */
+
+#ifndef _SBRMI_CORE_H_
+#define _SBRMI_CORE_H_
+
+#include <linux/mutex.h>
+#include <linux/i2c.h>
+#include <linux/platform_device.h>
+
+/* SB-RMI registers */
+enum sbrmi_reg {
+ SBRMI_CTRL = 0x01,
+ SBRMI_STATUS,
+ SBRMI_OUTBNDMSG0 = 0x30,
+ SBRMI_OUTBNDMSG1,
+ SBRMI_OUTBNDMSG2,
+ SBRMI_OUTBNDMSG3,
+ SBRMI_OUTBNDMSG4,
+ SBRMI_OUTBNDMSG5,
+ SBRMI_OUTBNDMSG6,
+ SBRMI_OUTBNDMSG7,
+ SBRMI_INBNDMSG0,
+ SBRMI_INBNDMSG1,
+ SBRMI_INBNDMSG2,
+ SBRMI_INBNDMSG3,
+ SBRMI_INBNDMSG4,
+ SBRMI_INBNDMSG5,
+ SBRMI_INBNDMSG6,
+ SBRMI_INBNDMSG7,
+ SBRMI_SW_INTERRUPT,
+};
+
+/*
+ * SB-RMI supports soft mailbox service request to MP1 (power management
+ * firmware) through SBRMI inbound/outbound message registers.
+ * SB-RMI message IDs
+ */
+enum sbrmi_msg_id {
+ SBRMI_READ_PKG_PWR_CONSUMPTION = 0x1,
+ SBRMI_WRITE_PKG_PWR_LIMIT,
+ SBRMI_READ_PKG_PWR_LIMIT,
+ SBRMI_READ_PKG_MAX_PWR_LIMIT,
+};
+
+/* Each client has this additional data */
+struct sbrmi_data {
+ struct i2c_client *client;
+ struct mutex lock;
+ struct platform_device *pdev;
+ u32 pwr_limit_max;
+};
+
+struct sbrmi_mailbox_msg {
+ u8 cmd;
+ bool read;
+ u32 data_in;
+ u32 data_out;
+};
+
+int rmi_mailbox_xfer(struct sbrmi_data *data, struct sbrmi_mailbox_msg *msg);
+int create_hwmon_sensor_device(struct device *dev, struct sbrmi_data *data);
+#endif /*_SBRMI_CORE_H_*/
diff --git a/drivers/misc/amd-sbi/rmi-hwmon.c b/drivers/misc/amd-sbi/rmi-hwmon.c
new file mode 100644
index 000000000000..36913f105eef
--- /dev/null
+++ b/drivers/misc/amd-sbi/rmi-hwmon.c
@@ -0,0 +1,121 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * rmi-hwmon.c - hwmon sensor support for side band RMI
+ *
+ * Copyright (C) 2024 Advanced Micro Devices, Inc.
+ */
+#include <linux/err.h>
+#include <linux/hwmon.h>
+#include "rmi-core.h"
+
+/* Do not allow setting negative power limit */
+#define SBRMI_PWR_MIN 0
+
+static int sbrmi_read(struct device *dev, enum hwmon_sensor_types type,
+ u32 attr, int channel, long *val)
+{
+ struct sbrmi_data *data = dev_get_drvdata(dev);
+ struct sbrmi_mailbox_msg msg = { 0 };
+ int ret;
+
+ if (!data)
+ return -ENODEV;
+
+ if (type != hwmon_power)
+ return -EINVAL;
+
+ msg.read = true;
+ switch (attr) {
+ case hwmon_power_input:
+ msg.cmd = SBRMI_READ_PKG_PWR_CONSUMPTION;
+ ret = rmi_mailbox_xfer(data, &msg);
+ break;
+ case hwmon_power_cap:
+ msg.cmd = SBRMI_READ_PKG_PWR_LIMIT;
+ ret = rmi_mailbox_xfer(data, &msg);
+ break;
+ case hwmon_power_cap_max:
+ msg.data_out = data->pwr_limit_max;
+ ret = 0;
+ break;
+ default:
+ return -EINVAL;
+ }
+ if (ret < 0)
+ return ret;
+ /* hwmon power attributes are in microWatt */
+ *val = (long)msg.data_out * 1000;
+ return ret;
+}
+
+static int sbrmi_write(struct device *dev, enum hwmon_sensor_types type,
+ u32 attr, int channel, long val)
+{
+ struct sbrmi_data *data = dev_get_drvdata(dev);
+ struct sbrmi_mailbox_msg msg = { 0 };
+
+ if (!data)
+ return -ENODEV;
+
+ if (type != hwmon_power && attr != hwmon_power_cap)
+ return -EINVAL;
+ /*
+ * hwmon power attributes are in microWatt
+ * mailbox read/write is in mWatt
+ */
+ val /= 1000;
+
+ val = clamp_val(val, SBRMI_PWR_MIN, data->pwr_limit_max);
+
+ msg.cmd = SBRMI_WRITE_PKG_PWR_LIMIT;
+ msg.data_in = val;
+ msg.read = false;
+
+ return rmi_mailbox_xfer(data, &msg);
+}
+
+static umode_t sbrmi_is_visible(const void *data,
+ enum hwmon_sensor_types type,
+ u32 attr, int channel)
+{
+ switch (type) {
+ case hwmon_power:
+ switch (attr) {
+ case hwmon_power_input:
+ case hwmon_power_cap_max:
+ return 0444;
+ case hwmon_power_cap:
+ return 0644;
+ }
+ break;
+ default:
+ break;
+ }
+ return 0;
+}
+
+static const struct hwmon_channel_info * const sbrmi_info[] = {
+ HWMON_CHANNEL_INFO(power,
+ HWMON_P_INPUT | HWMON_P_CAP | HWMON_P_CAP_MAX),
+ NULL
+};
+
+static const struct hwmon_ops sbrmi_hwmon_ops = {
+ .is_visible = sbrmi_is_visible,
+ .read = sbrmi_read,
+ .write = sbrmi_write,
+};
+
+static const struct hwmon_chip_info sbrmi_chip_info = {
+ .ops = &sbrmi_hwmon_ops,
+ .info = sbrmi_info,
+};
+
+int create_hwmon_sensor_device(struct device *dev, struct sbrmi_data *data)
+{
+ struct device *hwmon_dev;
+
+ hwmon_dev = devm_hwmon_device_register_with_info(dev, "sbrmi", data,
+ &sbrmi_chip_info, NULL);
+ return PTR_ERR_OR_ZERO(hwmon_dev);
+}
diff --git a/drivers/misc/amd-sbi/rmi-i2c.c b/drivers/misc/amd-sbi/rmi-i2c.c
new file mode 100644
index 000000000000..ae968cf3c29c
--- /dev/null
+++ b/drivers/misc/amd-sbi/rmi-i2c.c
@@ -0,0 +1,111 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * rmi-i2c.c - Side band RMI over I2C support for AMD out
+ * of band management
+ *
+ * Copyright (C) 2024 Advanced Micro Devices, Inc.
+ */
+
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include "rmi-core.h"
+
+#define SBRMI_CTRL 0x1
+
+static int sbrmi_enable_alert(struct i2c_client *client)
+{
+ int ctrl;
+
+ /*
+ * Enable the SB-RMI Software alert status
+ * by writing 0 to bit 4 of Control register(0x1)
+ */
+ ctrl = i2c_smbus_read_byte_data(client, SBRMI_CTRL);
+ if (ctrl < 0)
+ return ctrl;
+
+ if (ctrl & 0x10) {
+ ctrl &= ~0x10;
+ return i2c_smbus_write_byte_data(client,
+ SBRMI_CTRL, ctrl);
+ }
+
+ return 0;
+}
+
+static int sbrmi_get_max_pwr_limit(struct sbrmi_data *data)
+{
+ struct sbrmi_mailbox_msg msg = { 0 };
+ int ret;
+
+ msg.cmd = SBRMI_READ_PKG_MAX_PWR_LIMIT;
+ msg.read = true;
+ ret = rmi_mailbox_xfer(data, &msg);
+ if (ret < 0)
+ return ret;
+ data->pwr_limit_max = msg.data_out;
+
+ return ret;
+}
+
+static int sbrmi_i2c_probe(struct i2c_client *client)
+{
+ struct device *dev = &client->dev;
+ struct sbrmi_data *data;
+ int ret;
+
+ data = devm_kzalloc(dev, sizeof(struct sbrmi_data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ data->client = client;
+ mutex_init(&data->lock);
+
+ /* Enable alert for SB-RMI sequence */
+ ret = sbrmi_enable_alert(client);
+ if (ret < 0)
+ return ret;
+
+ /* Cache maximum power limit */
+ ret = sbrmi_get_max_pwr_limit(data);
+ if (ret < 0)
+ return ret;
+
+ dev_set_drvdata(dev, data);
+ return create_hwmon_sensor_device(dev, data);
+}
+
+static const struct i2c_device_id sbrmi_id[] = {
+ {"sbrmi-i2c"},
+ {}
+};
+MODULE_DEVICE_TABLE(i2c, sbrmi_id);
+
+static const struct of_device_id __maybe_unused sbrmi_of_match[] = {
+ {
+ .compatible = "amd,sbrmi",
+ },
+ { },
+};
+MODULE_DEVICE_TABLE(of, sbrmi_of_match);
+
+static struct i2c_driver sbrmi_driver = {
+ .driver = {
+ .name = "sbrmi-i2c",
+ .of_match_table = of_match_ptr(sbrmi_of_match),
+ },
+ .probe = sbrmi_i2c_probe,
+ .id_table = sbrmi_id,
+};
+
+module_i2c_driver(sbrmi_driver);
+
+MODULE_AUTHOR("Akshay Gupta <akshay.gupta@xxxxxxx>");
+MODULE_AUTHOR("Naveen Krishna Chatradhi <naveenkrishna.chatradhi@xxxxxxx>");
+MODULE_DESCRIPTION("Hwmon driver for AMD SB-RMI emulated sensor");
+MODULE_LICENSE("GPL");
--
2.44.0
