[PATCH v7] i2c: Add PCI and platform drivers for the AMD MP2 I2C controller

* [PATCH v7] i2c: Add PCI and platform drivers for the AMD MP2 I2C controller
@ 2018-10-27 15:09 Elie Morisse
  2018-10-30 20:56 ` Bjorn Helgaas
  0 siblings, 1 reply; 6+ messages in thread
From: Elie Morisse @ 2018-10-27 15:09 UTC (permalink / raw)
  To: linux-i2c, Wolfram Sang, helgaas, Nehal-bakulchandra.Shah,
	Shyam-sundar.S-k, sandeep.singh, linux-kernel

This contains two drivers:
 * i2c-amd-plat-mp2: platform driver managing an i2c adapter (one of
the two busses of the MP2) and routing any i2c read/write command to
the PCI driver.
 * i2c-amd-pci-mp2: PCI driver communicating through the C2P/P2C
mailbox registers, or through DMA for more than 32 bytes transfers.

This is major rework of the patch submitted by Nehal-bakulchandra Shah
from AMD (https://patchwork.kernel.org/patch/10597369/).

Most of the event handling of v2/v3 was rewritten since it couldn't work
if more than one bus was enabled, and contains many more fixes listed
in the patch changelog.

With those changes both the touchpad and the touchscreen of the
Ryzen-based Lenovo Yoga 530 which lie in separate busses work beautifully.

Signed-off-by: Elie Morisse <syniurge@gmail.com>
---
Changes since v1:(https://www.spinics.net/lists/linux-i2c/msg34650.html)
-> Add fix for IOMMU
-> Add depedency of ACPI
-> Add locks to avoid the crash

Changes since v2:(https://patchwork.ozlabs.org/patch/961270/)

-> fix for review comments
-> fix for more than 32 bytes write issue

Changes since v3 (https://patchwork.kernel.org/patch/10597369/) by Elie M.:

-> support more than one bus/adapter
-> support more than one slave per bus
-> use the bus speed specified by the slaves declared in the DSDT instead of
   assuming speed == 400kbits/s
-> instead of kzalloc'ing a buffer for every less than 32 bytes reads, simply
   use i2c_msg.buf
-> fix buffer overreads/overflows when (<=32 bytes) message lengths aren't a
   multiple of 4 by using memcpy_fromio and memcpy_toio
-> use streaming DMA mappings instead of allocating a coherent DMA buffer for
   every >32 bytes read/write
-> properly check for timeouts during i2c_amd_xfer and increase it from 50
   jiffies to 250 msecs (which is more in line with other drivers)
-> complete amd_i2c_dev.msg even if the device doesn't return a xxx_success
   event, instead of stalling i2c_amd_xfer
-> removed the spinlock and mdelay during i2c_amd_pci_configure, I didn't see
   the point since it's already waiting for a i2c_busenable_complete event
-> add an adapter-specific mutex lock for i2c_amd_xfer, since we don't want
   parallel calls writing to AMD_C2P_MSG0 (or AMD_C2P_MSG1)
-> add a global mutex lock for registers AMD_C2P_MSG2 to AMD_C2P_MSG9,  which
   are shared across the two busses/adapters
-> add MODULE_DEVICE_TABLE to automatically load i2c-amd-platdrv if the DSDT
   enumerates devices with the "AMDI0011" HID
-> set maximum length of reads/writes to 4095 (event's length field is 12 bits)
-> basic PM support
-> style corrections to match the kernel code style, and tried to reduce code
   duplication whenever possible

Changes since v4 (https://marc.info/?l=linux-kernel&m=154031133019835) by Elie M.:

-> fix missing typecast warning
-> removed the duplicated entry in Kconfig

Changes since v5 by Elie M.:

-> move DMA mapping from the platform driver to the PCI driver
-> attempt to find the platform device's PCI parent through the _DEP ACPI method
   (if not found take the first MP2 device registred in the i2c-amd-pci-mp2
   driver, like before)
-> do not assume anymore that the PCI device is owned by the i2c-amd-pci-mp2
   driver
-> address other review comments by Bjorn Helgaas (meant for v3)

Changes since v6 by Elie M.:

-> remove unnecessary memcpy from the DMA buffer during i2c_amd_read_completion

 MAINTAINERS                           |   6 +
 drivers/i2c/busses/Kconfig            |  15 +
 drivers/i2c/busses/Makefile           |   2 +
 drivers/i2c/busses/i2c-amd-pci-mp2.c  | 706 ++++++++++++++++++++++++++
 drivers/i2c/busses/i2c-amd-pci-mp2.h  | 224 ++++++++
 drivers/i2c/busses/i2c-amd-plat-mp2.c | 373 ++++++++++++++
 6 files changed, 1326 insertions(+)
 create mode 100644 drivers/i2c/busses/i2c-amd-pci-mp2.c
 create mode 100644 drivers/i2c/busses/i2c-amd-pci-mp2.h
 create mode 100644 drivers/i2c/busses/i2c-amd-plat-mp2.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 6ac000cc006d..8ff2bddc1ac2 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -791,6 +791,12 @@ F:	drivers/gpu/drm/amd/include/vi_structs.h
 F:	drivers/gpu/drm/amd/include/v9_structs.h
 F:	include/uapi/linux/kfd_ioctl.h
 
+AMD MP2 I2C DRIVER
+M:	Elie Morisse <syniurge@gmail.com>
+L:	linux-i2c@vger.kernel.org
+S:	Maintained
+F:	drivers/i2c/busses/i2c-amd-*-mp2*
+
 AMD POWERPLAY
 M:	Rex Zhu <rex.zhu@amd.com>
 M:	Evan Quan <evan.quan@amd.com>
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 451d4ae50e66..e20f2d1ce381 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -77,6 +77,21 @@ config I2C_AMD8111
 	  This driver can also be built as a module.  If so, the module
 	  will be called i2c-amd8111.
 
+config I2C_AMD_MP2_PCI
+	tristate
+	depends on PCI
+
+config I2C_AMD_MP2_PLATFORM
+	tristate "AMD MP2 Platform"
+	select I2C_AMD_MP2_PCI
+	depends on ACPI
+	help
+	  If you say yes to this option, support will be included for the AMD MP2
+	  PCI I2C adapter.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called i2c-amd-plat-mp2.
+
 config I2C_HIX5HD2
 	tristate "Hix5hd2 high-speed I2C driver"
 	depends on ARCH_HISI || ARCH_HIX5HD2 || COMPILE_TEST
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 18b26af82b1c..16ef646d7ef5 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -32,6 +32,8 @@ obj-$(CONFIG_I2C_POWERMAC)	+= i2c-powermac.o
 
 # Embedded system I2C/SMBus host controller drivers
 obj-$(CONFIG_I2C_ALTERA)	+= i2c-altera.o
+obj-$(CONFIG_I2C_AMD_MP2_PCI)	+= i2c-amd-pci-mp2.o
+obj-$(CONFIG_I2C_AMD_MP2_PLATFORM)	+= i2c-amd-plat-mp2.o
 obj-$(CONFIG_I2C_ASPEED)	+= i2c-aspeed.o
 obj-$(CONFIG_I2C_AT91)		+= i2c-at91.o
 obj-$(CONFIG_I2C_AU1550)	+= i2c-au1550.o
diff --git a/drivers/i2c/busses/i2c-amd-pci-mp2.c b/drivers/i2c/busses/i2c-amd-pci-mp2.c
new file mode 100644
index 000000000000..eb54825f3f69
--- /dev/null
+++ b/drivers/i2c/busses/i2c-amd-pci-mp2.c
@@ -0,0 +1,706 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
+/*
+ * AMD PCIe MP2 Communication Driver
+ *
+ * Authors: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
+ *          Elie Morisse <syniurge@gmail.com>
+ */
+
+#include <linux/debugfs.h>
+#include <linux/dma-mapping.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/slab.h>
+
+#include "i2c-amd-pci-mp2.h"
+
+#define DRIVER_NAME	"pcie_mp2_amd"
+#define DRIVER_DESC	"AMD(R) PCI-E MP2 Communication Driver"
+#define DRIVER_VER	"1.0"
+
+static const struct file_operations amd_mp2_debugfs_info;
+static struct dentry *debugfs_dir;
+
+#define write64 _write64
+static inline void _write64(u64 val, void __iomem *mmio)
+{
+	writel(val, mmio);
+	writel(val >> 32, mmio + sizeof(u32));
+}
+
+#define read64 _read64
+static inline u64 _read64(void __iomem *mmio)
+{
+	u64 low, high;
+
+	low = readl(mmio);
+	high = readl(mmio + sizeof(u32));
+	return low | (high << 32);
+}
+
+static int amd_mp2_cmd(struct amd_mp2_dev *privdata,
+		       union i2c_cmd_base i2c_cmd_base)
+{
+	void __iomem *reg;
+
+	if (i2c_cmd_base.s.bus_id > 1) {
+		dev_err(ndev_dev(privdata), "%s Invalid bus id\n", __func__);
+		return -EINVAL;
+	}
+
+	reg = privdata->mmio + ((i2c_cmd_base.s.bus_id == 1) ?
+				AMD_C2P_MSG1 : AMD_C2P_MSG0);
+	writel(i2c_cmd_base.ul, reg);
+
+	return 0;
+}
+
+int amd_mp2_connect(struct amd_i2c_common *i2c_common, bool enable)
+{
+	struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
+	union i2c_cmd_base i2c_cmd_base;
+
+	dev_dbg(ndev_dev(privdata), "%s id: %d\n", __func__,
+		i2c_common->bus_id);
+
+	i2c_common->reqcmd = enable ? i2c_enable : i2c_disable;
+
+	i2c_cmd_base.ul = 0;
+	i2c_cmd_base.s.i2c_cmd = i2c_common->reqcmd;
+	i2c_cmd_base.s.bus_id = i2c_common->bus_id;
+	i2c_cmd_base.s.i2c_speed = i2c_common->i2c_speed;
+
+	return amd_mp2_cmd(privdata, i2c_cmd_base);
+}
+EXPORT_SYMBOL_GPL(amd_mp2_connect);
+
+static void amd_mp2_cmd_rw_fill(struct amd_i2c_common *i2c_common,
+				union i2c_cmd_base *i2c_cmd_base,
+				enum i2c_cmd reqcmd)
+{
+	i2c_common->reqcmd = reqcmd;
+
+	i2c_cmd_base->s.i2c_cmd = reqcmd;
+	i2c_cmd_base->s.bus_id = i2c_common->bus_id;
+	i2c_cmd_base->s.i2c_speed = i2c_common->i2c_speed;
+	i2c_cmd_base->s.slave_addr = i2c_common->rw_cfg.slave_addr;
+	i2c_cmd_base->s.length = i2c_common->rw_cfg.length;
+}
+
+static int amd_mp2_dma_map(struct amd_mp2_dev *privdata,
+			   struct amd_i2c_common *i2c_common,
+			   bool is_write)
+{
+	enum dma_data_direction dma_direction = is_write ?
+			DMA_TO_DEVICE : DMA_FROM_DEVICE;
+
+	i2c_common->rw_cfg.dma_addr = dma_map_single(&privdata->pci_dev->dev,
+						     i2c_common->rw_cfg.buf,
+						     i2c_common->rw_cfg.length,
+						     dma_direction);
+	i2c_common->rw_cfg.dma_direction = dma_direction;
+
+	if (dma_mapping_error(&privdata->pci_dev->dev,
+			      i2c_common->rw_cfg.dma_addr)) {
+		dev_err(ndev_dev(privdata),
+			"Error while mapping dma buffer %p\n",
+			i2c_common->rw_cfg.buf);
+		return -EIO;
+	}
+
+	return 0;
+}
+
+static void amd_mp2_dma_unmap(struct amd_mp2_dev *privdata,
+			      struct amd_i2c_common *i2c_common)
+{
+	dma_unmap_single(&privdata->pci_dev->dev,
+			 i2c_common->rw_cfg.dma_addr,
+			 i2c_common->rw_cfg.length,
+			 i2c_common->rw_cfg.dma_direction);
+}
+
+int amd_mp2_read(struct amd_i2c_common *i2c_common)
+{
+	struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
+	union i2c_cmd_base i2c_cmd_base;
+
+	dev_dbg(ndev_dev(privdata), "%s addr: %x id: %d\n", __func__,
+		i2c_common->rw_cfg.slave_addr, i2c_common->bus_id);
+
+	amd_mp2_cmd_rw_fill(i2c_common, &i2c_cmd_base, i2c_read);
+
+	/* there is only one data mailbox for two i2c adapters */
+	mutex_lock(&privdata->c2p_lock);
+
+	if (!i2c_common->rw_cfg.buf) {
+		dev_err(ndev_dev(privdata), "%s no mem for buf received\n",
+			__func__);
+		return -ENOMEM;
+	}
+
+	if (i2c_common->rw_cfg.length <= 32) {
+		i2c_cmd_base.s.mem_type = use_c2pmsg;
+	} else {
+		i2c_cmd_base.s.mem_type = use_dram;
+		if (amd_mp2_dma_map(privdata, i2c_common, false))
+			return -EIO;
+		write64((u64)i2c_common->rw_cfg.dma_addr,
+			privdata->mmio + AMD_C2P_MSG2);
+	}
+
+	return amd_mp2_cmd(privdata, i2c_cmd_base);
+}
+EXPORT_SYMBOL_GPL(amd_mp2_read);
+
+int amd_mp2_write(struct amd_i2c_common *i2c_common)
+{
+	struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
+	union i2c_cmd_base i2c_cmd_base;
+
+	dev_dbg(ndev_dev(privdata), "%s addr: %x id: %d\n", __func__,
+		i2c_common->rw_cfg.slave_addr, i2c_common->bus_id);
+
+	amd_mp2_cmd_rw_fill(i2c_common, &i2c_cmd_base, i2c_write);
+
+	/* there is only one data mailbox for two i2c adapters */
+	mutex_lock(&privdata->c2p_lock);
+
+	if (i2c_common->rw_cfg.length <= 32) {
+		i2c_cmd_base.s.mem_type = use_c2pmsg;
+		memcpy_toio(privdata->mmio + AMD_C2P_MSG2,
+			    i2c_common->rw_cfg.buf,
+			    i2c_common->rw_cfg.length);
+	} else {
+		i2c_cmd_base.s.mem_type = use_dram;
+		if (amd_mp2_dma_map(privdata, i2c_common, true))
+			return -EIO;
+		write64((u64)i2c_common->rw_cfg.dma_addr,
+			privdata->mmio + AMD_C2P_MSG2);
+	}
+
+	return amd_mp2_cmd(privdata, i2c_cmd_base);
+}
+EXPORT_SYMBOL_GPL(amd_mp2_write);
+
+static void amd_mp2_pci_do_work(struct work_struct *work)
+{
+	struct amd_i2c_common *i2c_common = work_amd_i2c_common(work);
+	struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
+	int sts = i2c_common->eventval.r.status;
+	int res = i2c_common->eventval.r.response;
+	int len = i2c_common->eventval.r.length;
+	u32 slave_addr = i2c_common->eventval.r.slave_addr;
+
+	if (len != i2c_common->rw_cfg.length)
+		dev_err(ndev_dev(privdata),
+			"length %d in event doesn't match buffer length %d!\n",
+			len, i2c_common->rw_cfg.length);
+	if (slave_addr != i2c_common->rw_cfg.slave_addr)
+		dev_err(ndev_dev(privdata),
+			"unexpected slave address %x (expected: %x)!\n",
+			slave_addr, i2c_common->rw_cfg.slave_addr);
+
+	if (res != command_success) {
+		if (res == command_failed)
+			dev_err(ndev_dev(privdata), "i2c command failed!\n");
+		else
+			dev_err(ndev_dev(privdata), "invalid response to i2c command!\n");
+		return;
+	}
+
+	switch (i2c_common->reqcmd) {
+	case i2c_read:
+		if (sts == i2c_readcomplete_event) {
+			if (len <= 32)
+				memcpy_fromio(i2c_common->rw_cfg.buf,
+					      privdata->mmio + AMD_C2P_MSG2,
+					      i2c_common->rw_cfg.length);
+		} else if (sts == i2c_readfail_event) {
+			dev_err(ndev_dev(privdata), "i2c read failed!\n");
+		} else {
+			dev_err(ndev_dev(privdata), "invalid i2c status after read!\n");
+		}
+
+		i2c_common->ops->read_complete(&i2c_common->eventval);
+		break;
+	case i2c_write:
+		if (sts == i2c_writefail_event)
+			dev_err(ndev_dev(privdata), "i2c write failed!\n");
+		else if (sts != i2c_writecomplete_event)
+			dev_err(ndev_dev(privdata), "invalid i2c status after write!\n");
+
+		i2c_common->ops->write_complete(&i2c_common->eventval);
+		break;
+	case i2c_enable:
+		if (sts == i2c_busdisable_failed)
+			dev_err(ndev_dev(privdata), "i2c bus enable failed!\n");
+		else if (sts != i2c_busenable_complete)
+			dev_err(ndev_dev(privdata), "invalid i2c status after bus enable!\n");
+
+		i2c_common->ops->connect_complete(&i2c_common->eventval);
+		break;
+	default:
+		break;
+	}
+
+	if ((i2c_common->reqcmd == i2c_read ||
+	     i2c_common->reqcmd == i2c_write) &&
+	    i2c_common->rw_cfg.length > 32)
+		amd_mp2_dma_unmap(privdata, i2c_common);
+}
+
+static void amd_mp2_pci_work(struct work_struct *work)
+{
+	struct amd_i2c_common *i2c_common = work_amd_i2c_common(work);
+	struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
+	enum i2c_cmd cmd = i2c_common->reqcmd;
+
+	amd_mp2_pci_do_work(work);
+
+	i2c_common->reqcmd = i2c_none;
+
+	if (cmd == i2c_read || cmd == i2c_write)
+		mutex_unlock(&privdata->c2p_lock);
+}
+
+static irqreturn_t amd_mp2_irq_isr(int irq, void *dev)
+{
+	struct amd_mp2_dev *privdata = dev;
+	struct amd_i2c_common *i2c_common;
+	u32 val;
+	unsigned int bus_id;
+	void __iomem *reg;
+	unsigned long flags;
+	enum irqreturn ret = IRQ_NONE;
+
+	raw_spin_lock_irqsave(&privdata->lock, flags);
+
+	for (bus_id = 0; bus_id < 2; bus_id++) {
+		reg = privdata->mmio + ((bus_id == 0) ?
+					AMD_P2C_MSG1 : AMD_P2C_MSG2);
+		val = readl(reg);
+		if (val != 0) {
+			i2c_common = privdata->plat_common[bus_id];
+			if (!i2c_common)
+				continue;
+			i2c_common->eventval.ul = val;
+
+			writel(0, reg);
+			writel(0, privdata->mmio + AMD_P2C_MSG_INTEN);
+
+			if (i2c_common->reqcmd != i2c_none)
+				schedule_delayed_work(&i2c_common->work, 0);
+
+			ret = IRQ_HANDLED;
+		}
+	}
+
+	raw_spin_unlock_irqrestore(&privdata->lock, flags);
+	return ret;
+}
+
+int amd_i2c_register_cb(struct amd_mp2_dev *privdata,
+			struct amd_i2c_common *i2c_common)
+{
+	if (i2c_common->bus_id > 1)
+		return -EINVAL;
+	privdata->plat_common[i2c_common->bus_id] = i2c_common;
+
+	INIT_DELAYED_WORK(&i2c_common->work, amd_mp2_pci_work);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(amd_i2c_register_cb);
+
+int amd_i2c_unregister_cb(struct amd_mp2_dev *privdata,
+			  struct amd_i2c_common *i2c_common)
+{
+	cancel_delayed_work_sync(&i2c_common->work);
+	privdata->plat_common[i2c_common->bus_id] = NULL;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(amd_i2c_unregister_cb);
+
+static ssize_t amd_mp2_debugfs_read(struct file *filp, char __user *ubuf,
+				    size_t count, loff_t *offp)
+{
+	struct amd_mp2_dev *privdata;
+	void __iomem *mmio;
+	u8 *buf;
+	size_t buf_size;
+	ssize_t ret, off;
+	u32 v32;
+
+	privdata = filp->private_data;
+	mmio = privdata->mmio;
+	buf_size = min_t(size_t, count, 0x800);
+	buf = kmalloc(buf_size, GFP_KERNEL);
+
+	if (!buf)
+		return -ENOMEM;
+
+	off = 0;
+	off += scnprintf(buf + off, buf_size - off,
+			"Mp2 Device Information:\n");
+
+	off += scnprintf(buf + off, buf_size - off,
+			"========================\n");
+	off += scnprintf(buf + off, buf_size - off,
+			"\tMP2 C2P Message Register Dump:\n\n");
+	v32 = readl(privdata->mmio + AMD_C2P_MSG0);
+	off += scnprintf(buf + off, buf_size - off,
+			"AMD_C2P_MSG0 -\t\t\t%#06x\n", v32);
+
+	v32 = readl(privdata->mmio + AMD_C2P_MSG1);
+	off += scnprintf(buf + off, buf_size - off,
+			"AMD_C2P_MSG1 -\t\t\t%#06x\n", v32);
+
+	v32 = readl(privdata->mmio + AMD_C2P_MSG2);
+	off += scnprintf(buf + off, buf_size - off,
+			"AMD_C2P_MSG2 -\t\t\t%#06x\n", v32);
+
+	v32 = readl(privdata->mmio + AMD_C2P_MSG3);
+	off += scnprintf(buf + off, buf_size - off,
+			"AMD_C2P_MSG3 -\t\t\t%#06x\n", v32);
+
+	v32 = readl(privdata->mmio + AMD_C2P_MSG4);
+	off += scnprintf(buf + off, buf_size - off,
+			"AMD_C2P_MSG4 -\t\t\t%#06x\n", v32);
+
+	v32 = readl(privdata->mmio + AMD_C2P_MSG5);
+	off += scnprintf(buf + off, buf_size - off,
+			"AMD_C2P_MSG5 -\t\t\t%#06x\n", v32);
+
+	v32 = readl(privdata->mmio + AMD_C2P_MSG6);
+	off += scnprintf(buf + off, buf_size - off,
+			"AMD_C2P_MSG6 -\t\t\t%#06x\n", v32);
+
+	v32 = readl(privdata->mmio + AMD_C2P_MSG7);
+	off += scnprintf(buf + off, buf_size - off,
+			"AMD_C2P_MSG7 -\t\t\t%#06x\n", v32);
+
+	v32 = readl(privdata->mmio + AMD_C2P_MSG8);
+	off += scnprintf(buf + off, buf_size - off,
+			"AMD_C2P_MSG8 -\t\t\t%#06x\n", v32);
+
+	v32 = readl(privdata->mmio + AMD_C2P_MSG9);
+	off += scnprintf(buf + off, buf_size - off,
+			"AMD_C2P_MSG9 -\t\t\t%#06x\n", v32);
+
+	off += scnprintf(buf + off, buf_size - off,
+			"\n\tMP2 P2C Message Register Dump:\n\n");
+
+	v32 = readl(privdata->mmio + AMD_P2C_MSG1);
+	off += scnprintf(buf + off, buf_size - off,
+			"AMD_P2C_MSG1 -\t\t\t%#06x\n", v32);
+
+	v32 = readl(privdata->mmio + AMD_P2C_MSG2);
+	off += scnprintf(buf + off, buf_size - off,
+			"AMD_P2C_MSG2 -\t\t\t%#06x\n", v32);
+
+	v32 = readl(privdata->mmio + AMD_P2C_MSG_INTEN);
+	off += scnprintf(buf + off, buf_size - off,
+			"AMD_P2C_MSG_INTEN -\t\t%#06x\n", v32);
+
+	v32 = readl(privdata->mmio + AMD_P2C_MSG_INTSTS);
+	off += scnprintf(buf + off, buf_size - off,
+			"AMD_P2C_MSG_INTSTS -\t\t%#06x\n", v32);
+
+	ret = simple_read_from_buffer(ubuf, count, offp, buf, off);
+	kfree(buf);
+	return ret;
+}
+
+static void amd_mp2_init_debugfs(struct amd_mp2_dev *privdata)
+{
+	if (!debugfs_dir) {
+		privdata->debugfs_dir = NULL;
+		privdata->debugfs_info = NULL;
+		return;
+	}
+
+	privdata->debugfs_dir = debugfs_create_dir(ndev_name(privdata),
+						   debugfs_dir);
+	if (!privdata->debugfs_dir) {
+		privdata->debugfs_info = NULL;
+	} else {
+		privdata->debugfs_info = debugfs_create_file
+			("info", 0400, privdata->debugfs_dir,
+			 privdata, &amd_mp2_debugfs_info);
+	}
+}
+
+static void amd_mp2_deinit_debugfs(struct amd_mp2_dev *privdata)
+{
+	debugfs_remove_recursive(privdata->debugfs_dir);
+}
+
+static void amd_mp2_clear_reg(struct amd_mp2_dev *privdata)
+{
+	int reg;
+
+	for (reg = AMD_C2P_MSG0; reg <= AMD_C2P_MSG9; reg += 4)
+		writel(0, privdata->mmio + reg);
+
+	for (reg = AMD_P2C_MSG0; reg <= AMD_P2C_MSG2; reg += 4)
+		writel(0, privdata->mmio + reg);
+}
+
+static int amd_mp2_pci_init(struct amd_mp2_dev *privdata,
+			    struct pci_dev *pci_dev)
+{
+	int rc;
+	resource_size_t size, base;
+
+	pci_set_drvdata(pci_dev, privdata);
+
+	rc = pci_enable_device(pci_dev);
+	if (rc)
+		goto err_pci_enable;
+
+	rc = pci_request_regions(pci_dev, DRIVER_NAME);
+	if (rc)
+		goto err_pci_regions;
+
+	pci_set_master(pci_dev);
+
+	rc = pci_set_dma_mask(pci_dev, DMA_BIT_MASK(64));
+	if (rc) {
+		rc = pci_set_dma_mask(pci_dev, DMA_BIT_MASK(32));
+		if (rc)
+			goto err_dma_mask;
+		dev_warn(ndev_dev(privdata), "Cannot DMA highmem\n");
+	}
+
+	rc = pci_set_consistent_dma_mask(pci_dev, DMA_BIT_MASK(64));
+	if (rc) {
+		rc = pci_set_consistent_dma_mask(pci_dev, DMA_BIT_MASK(32));
+		if (rc)
+			goto err_dma_mask;
+		dev_warn(ndev_dev(privdata), "Cannot DMA consistent highmem\n");
+	}
+
+	base = pci_resource_start(pci_dev, 2);
+	size = pci_resource_len(pci_dev, 2);
+	dev_dbg(ndev_dev(privdata), "Base addr:%zx size:%zx\n",
+		(size_t)base, (size_t)size);
+
+	mutex_init(&privdata->c2p_lock);
+	privdata->mmio = ioremap(base, size);
+	if (!privdata->mmio) {
+		rc = -EIO;
+		goto err_dma_mask;
+	}
+
+	/* Try to set up intx irq */
+	raw_spin_lock_init(&privdata->lock);
+	pci_intx(pci_dev, 1);
+	rc = request_irq(pci_dev->irq, amd_mp2_irq_isr, IRQF_SHARED,
+			 "mp2_irq_isr", privdata);
+	if (rc)
+		goto err_intx_request;
+
+	return 0;
+
+err_intx_request:
+	return rc;
+err_dma_mask:
+	pci_clear_master(pci_dev);
+	pci_release_regions(pci_dev);
+err_pci_regions:
+	pci_disable_device(pci_dev);
+err_pci_enable:
+	pci_set_drvdata(pci_dev, NULL);
+	return rc;
+}
+
+static void amd_mp2_pci_deinit(struct amd_mp2_dev *privdata)
+{
+	struct pci_dev *pci_dev = ndev_pdev(privdata);
+
+	pci_iounmap(pci_dev, privdata->mmio);
+
+	pci_clear_master(pci_dev);
+	pci_release_regions(pci_dev);
+	pci_disable_device(pci_dev);
+	pci_set_drvdata(pci_dev, NULL);
+}
+
+static int amd_mp2_pci_probe(struct pci_dev *pci_dev,
+			     const struct pci_device_id *id)
+{
+	struct amd_mp2_dev *privdata;
+	int rc;
+	static bool first_probe = true;
+
+	if (first_probe) {
+		pr_info("%s: %s Version: %s\n", DRIVER_NAME,
+			DRIVER_DESC, DRIVER_VER);
+		first_probe = false;
+	}
+
+	dev_info(&pci_dev->dev, "MP2 device found [%04x:%04x] (rev %x)\n",
+		 (int)pci_dev->vendor, (int)pci_dev->device,
+		 (int)pci_dev->revision);
+
+	privdata = kzalloc(sizeof(*privdata), GFP_KERNEL);
+	if (!privdata) {
+		rc = -ENOMEM;
+		goto err_dev;
+	}
+
+	privdata->pci_dev = pci_dev;
+
+	rc = amd_mp2_pci_init(privdata, pci_dev);
+	if (rc)
+		goto err_pci_init;
+	dev_dbg(&pci_dev->dev, "pci init done.\n");
+
+	amd_mp2_init_debugfs(privdata);
+	dev_info(&pci_dev->dev, "MP2 device registered.\n");
+	return 0;
+
+err_pci_init:
+	kfree(privdata);
+err_dev:
+	dev_err(&pci_dev->dev, "Memory Allocation Failed\n");
+	return rc;
+}
+
+static void amd_mp2_pci_remove(struct pci_dev *pci_dev)
+{
+	struct amd_mp2_dev *privdata = pci_get_drvdata(pci_dev);
+	unsigned int bus_id;
+
+	for (bus_id = 0; bus_id < 2; bus_id++)
+		if (privdata->plat_common[bus_id])
+			amd_i2c_unregister_cb(privdata,
+					      privdata->plat_common[bus_id]);
+
+	amd_mp2_deinit_debugfs(privdata);
+	amd_mp2_clear_reg(privdata);
+	free_irq(pci_dev->irq, privdata);
+	pci_intx(pci_dev, 0);
+	amd_mp2_pci_deinit(privdata);
+	kfree(privdata);
+}
+
+static const struct file_operations amd_mp2_debugfs_info = {
+	.owner = THIS_MODULE,
+	.open = simple_open,
+	.read = amd_mp2_debugfs_read,
+};
+
+static const struct pci_device_id amd_mp2_pci_tbl[] = {
+	{PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_MP2)},
+	{0}
+};
+MODULE_DEVICE_TABLE(pci, amd_mp2_pci_tbl);
+
+#ifdef CONFIG_PM_SLEEP
+static int amd_mp2_pci_device_suspend(struct pci_dev *pci_dev,
+				      pm_message_t mesg)
+{
+	int ret;
+	struct amd_mp2_dev *privdata = pci_get_drvdata(pci_dev);
+
+	if (!privdata)
+		return -EINVAL;
+
+	ret = pci_save_state(pci_dev);
+	if (ret) {
+		dev_err(ndev_dev(privdata),
+			"pci_save_state failed = %d\n", ret);
+		return ret;
+	}
+
+	pci_enable_wake(pci_dev, PCI_D3hot, 0);
+	pci_disable_device(pci_dev);
+	pci_set_power_state(pci_dev, pci_choose_state(pci_dev, mesg));
+
+	return 0;
+}
+
+static int amd_mp2_pci_device_resume(struct pci_dev *pci_dev)
+{
+	struct amd_mp2_dev *privdata = pci_get_drvdata(pci_dev);
+
+	if (!privdata)
+		return -EINVAL;
+
+	pci_set_power_state(pci_dev, PCI_D0);
+	pci_restore_state(pci_dev);
+
+	if (pci_enable_device(pci_dev) < 0) {
+		dev_err(ndev_dev(privdata), "pci_enable_device failed\n");
+		return -EIO;
+	}
+
+	pci_enable_wake(pci_dev, PCI_D3hot, 0);
+
+	return 0;
+}
+#endif
+
+static struct pci_driver amd_mp2_pci_driver = {
+	.name		= DRIVER_NAME,
+	.id_table	= amd_mp2_pci_tbl,
+	.probe		= amd_mp2_pci_probe,
+	.remove		= amd_mp2_pci_remove,
+#ifdef CONFIG_PM_SLEEP
+	.suspend		= amd_mp2_pci_device_suspend,
+	.resume			= amd_mp2_pci_device_resume,
+#endif
+};
+
+static int amd_mp2_device_match(struct device *dev, void *data)
+{
+	struct pci_dev *candidate = data;
+
+	if (!candidate)
+		return 1;
+	return (to_pci_dev(dev) == candidate) ? 1 : 0;
+}
+
+struct amd_mp2_dev *amd_mp2_find_device(struct pci_dev *candidate)
+{
+	struct device *dev;
+	struct pci_dev *pci_dev;
+
+	dev = driver_find_device(&amd_mp2_pci_driver.driver, NULL, candidate,
+				 amd_mp2_device_match);
+	if (!dev && candidate)
+		dev = driver_find_device(&amd_mp2_pci_driver.driver, NULL, NULL,
+					 amd_mp2_device_match);
+	if (!dev)
+		return NULL;
+
+	pci_dev = to_pci_dev(dev);
+	return (struct amd_mp2_dev *)pci_get_drvdata(pci_dev);
+}
+EXPORT_SYMBOL_GPL(amd_mp2_find_device);
+
+static int __init amd_mp2_pci_driver_init(void)
+{
+	if (debugfs_initialized())
+		debugfs_dir = debugfs_create_dir(KBUILD_MODNAME, NULL);
+
+	return pci_register_driver(&amd_mp2_pci_driver);
+}
+module_init(amd_mp2_pci_driver_init);
+
+static void __exit amd_mp2_pci_driver_exit(void)
+{
+	pci_unregister_driver(&amd_mp2_pci_driver);
+	debugfs_remove_recursive(debugfs_dir);
+}
+module_exit(amd_mp2_pci_driver_exit);
+
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_VERSION(DRIVER_VER);
+MODULE_AUTHOR("Shyam Sundar S K <Shyam-sundar.S-k@amd.com>");
+MODULE_AUTHOR("Elie Morisse <syniurge@gmail.com>");
+MODULE_LICENSE("Dual BSD/GPL");
diff --git a/drivers/i2c/busses/i2c-amd-pci-mp2.h b/drivers/i2c/busses/i2c-amd-pci-mp2.h
new file mode 100644
index 000000000000..65601b6ba3b3
--- /dev/null
+++ b/drivers/i2c/busses/i2c-amd-pci-mp2.h
@@ -0,0 +1,224 @@
+/* SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause */
+/*
+ * AMD PCIe MP2 Communication Driver
+ *
+ * Authors: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
+ *          Elie Morisse <syniurge@gmail.com>
+ */
+
+#ifndef I2C_AMD_PCI_MP2_H
+#define I2C_AMD_PCI_MP2_H
+
+#include <linux/pci.h>
+
+#define PCI_DEVICE_ID_AMD_MP2	0x15E6
+
+struct amd_i2c_common;
+struct amd_mp2_dev;
+
+enum {
+	/* MP2 C2P Message Registers */
+	AMD_C2P_MSG0 = 0x10500,			/* MP2 Message for I2C0 */
+	AMD_C2P_MSG1 = 0x10504,			/* MP2 Message for I2C1 */
+	AMD_C2P_MSG2 = 0x10508,			/* DRAM Address Lo / Data 0 */
+	AMD_C2P_MSG3 = 0x1050c,			/* DRAM Address HI / Data 1 */
+	AMD_C2P_MSG4 = 0x10510,			/* Data 2 */
+	AMD_C2P_MSG5 = 0x10514,			/* Data 3 */
+	AMD_C2P_MSG6 = 0x10518,			/* Data 4 */
+	AMD_C2P_MSG7 = 0x1051c,			/* Data 5 */
+	AMD_C2P_MSG8 = 0x10520,			/* Data 6 */
+	AMD_C2P_MSG9 = 0x10524,			/* Data 7 */
+
+	/* MP2 P2C Message Registers */
+	AMD_P2C_MSG0 = 0x10680,			/* Do not use */
+	AMD_P2C_MSG1 = 0x10684,			/* I2C0 interrupt register */
+	AMD_P2C_MSG2 = 0x10688,			/* I2C1 interrupt register */
+	AMD_P2C_MSG3 = 0x1068C,			/* MP2 debug info */
+	AMD_P2C_MSG_INTEN = 0x10690,	/* MP2 interrupt gen register */
+	AMD_P2C_MSG_INTSTS = 0x10694,	/* Interrupt status */
+};
+
+/* Command register data structures */
+
+#define i2c_none (-1)
+enum i2c_cmd {
+	i2c_read = 0,
+	i2c_write,
+	i2c_enable,
+	i2c_disable,
+	number_of_sensor_discovered,
+	is_mp2_active,
+	invalid_cmd = 0xF,
+};
+
+enum speed_enum {
+	speed100k = 0,
+	speed400k = 1,
+	speed1000k = 2,
+	speed1400k = 3,
+	speed3400k = 4
+};
+
+enum mem_type {
+	use_dram = 0,
+	use_c2pmsg = 1,
+};
+
+/**
+ * union i2c_cmd_base : bit access of C2P commands
+ * @i2c_cmd: bit 0..3 i2c R/W command
+ * @bus_id: bit 4..7 i2c bus index
+ * @slave_addr: bit 8..15 slave address
+ * @length: bit 16..27 read/write length
+ * @i2c_speed: bit 28..30 bus speed
+ * @mem_type: bit 31 0-DRAM; 1-C2P msg o/p
+ */
+union i2c_cmd_base {
+	u32 ul;
+	struct {
+		enum i2c_cmd i2c_cmd : 4;
+		u8 bus_id : 4;
+		u32 slave_addr : 8;
+		u32 length : 12;
+		enum speed_enum i2c_speed : 3;
+		enum mem_type mem_type : 1;
+	} s;
+};
+
+/* Response - Response of SFI */
+enum response_type {
+	invalid_response = 0,
+	command_success = 1,
+	command_failed = 2,
+};
+
+/* Status - Command ID to indicate a command */
+enum status_type {
+	i2c_readcomplete_event = 0,
+	i2c_readfail_event = 1,
+	i2c_writecomplete_event = 2,
+	i2c_writefail_event = 3,
+	i2c_busenable_complete = 4,
+	i2c_busenable_failed = 5,
+	i2c_busdisable_complete = 6,
+	i2c_busdisable_failed = 7,
+	invalid_data_length = 8,
+	invalid_slave_address = 9,
+	invalid_i2cbus_id = 10,
+	invalid_dram_addr = 11,
+	invalid_command = 12,
+	mp2_active = 13,
+	numberof_sensors_discovered_resp = 14,
+	i2c_bus_notinitialized
+};
+
+/**
+ * union i2c_event : bit access of P2C events
+ * @response: bit 0..1 i2c response type
+ * @status: bit 2..6 status_type
+ * @mem_type: bit 7 0-DRAM; 1-C2P msg o/p
+ * @bus_id: bit 8..11 i2c bus id
+ * @length: bit 12..23 message length
+ * @slave_addr: bit 24-31 slave address
+ */
+union i2c_event {
+	u32 ul;
+	struct {
+		enum response_type response : 2;
+		enum status_type status : 5;
+		enum mem_type mem_type : 1;
+		u8 bus_id : 4;
+		u32 length : 12;
+		u32 slave_addr : 8;
+	} r;
+};
+
+/**
+ * struct i2c_rw_config - i2c read/write settings
+ * @slave_addr: slave address
+ * @length: message length
+ * @buf: buffer address
+ * @dma_addr: if length > 32, holds the DMA buffer address
+ * @dma_direction: if length > 32, is either FROM or TO device
+ */
+struct i2c_rw_config {
+	u16 slave_addr;
+	u32 length;
+	u32 *buf;
+	dma_addr_t dma_addr;
+	enum dma_data_direction dma_direction;
+};
+
+/**
+ * struct amd_i2c_pci_ops - platdrv hooks
+ */
+struct amd_i2c_pci_ops {
+	int (*read_complete)(union i2c_event *event);
+	int (*write_complete)(union i2c_event *event);
+	int (*connect_complete)(union i2c_event *event);
+};
+
+/**
+ * struct amd_i2c_common - per bus/i2c adapter context, shared
+ *		between the pci and the platform driver
+ * @eventval: MP2 event value set by the IRQ handler to be processed
+ *		by the worker
+ * @ops: platdrv hooks
+ * @rw_cfg: settings for reads/writes
+ * @work: delayed worker struct
+ * @reqcmd: i2c command type requested by platdrv
+ * @requested: true if the interrupt answered a request from platdrv
+ * @bus_id: bus index
+ * @i2c_speed: i2c bus speed determined by the slowest slave
+ */
+struct amd_i2c_common {
+	union i2c_event eventval;
+	const struct amd_i2c_pci_ops *ops;
+	struct amd_mp2_dev *mp2_dev;
+	struct i2c_rw_config rw_cfg;
+	struct delayed_work work;
+	enum i2c_cmd reqcmd;
+	u8 bus_id;
+	enum speed_enum i2c_speed;
+};
+
+/**
+ * struct amd_mp2_dev - per PCI device context
+ * @pci_dev: PCI driver node
+ * @plat_common: MP2 devices may have up to two busses,
+ *		each bus corresponding to an i2c adapter
+ * @mmio: iommapped registers
+ * @lock: interrupt spinlock
+ * @c2p_lock: controls access to the C2P mailbox shared between
+ *		the two adapters
+ */
+struct amd_mp2_dev {
+	struct pci_dev *pci_dev;
+	struct amd_i2c_common *plat_common[2];
+	void __iomem *mmio;
+	raw_spinlock_t lock;
+	struct mutex c2p_lock;
+	struct dentry *debugfs_dir;
+	struct dentry *debugfs_info;
+};
+
+int amd_mp2_read(struct amd_i2c_common *i2c_common);
+int amd_mp2_write(struct amd_i2c_common *i2c_common);
+int amd_mp2_connect(struct amd_i2c_common *i2c_common, bool enable);
+
+int amd_i2c_register_cb(struct amd_mp2_dev *mp2_dev,
+			struct amd_i2c_common *i2c_common);
+int amd_i2c_unregister_cb(struct amd_mp2_dev *mp2_dev,
+			  struct amd_i2c_common *i2c_common);
+
+struct amd_mp2_dev *amd_mp2_find_device(struct pci_dev *candidate);
+
+#define ndev_pdev(ndev) ((ndev)->pci_dev)
+#define ndev_name(ndev) pci_name(ndev_pdev(ndev))
+#define ndev_dev(ndev) (&ndev_pdev(ndev)->dev)
+#define work_amd_i2c_common(__work) \
+	container_of(__work, struct amd_i2c_common, work.work)
+#define event_amd_i2c_common(__event) \
+	container_of(__event, struct amd_i2c_common, eventval)
+
+#endif
diff --git a/drivers/i2c/busses/i2c-amd-plat-mp2.c b/drivers/i2c/busses/i2c-amd-plat-mp2.c
new file mode 100644
index 000000000000..a10bd08fe1db
--- /dev/null
+++ b/drivers/i2c/busses/i2c-amd-plat-mp2.c
@@ -0,0 +1,373 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
+/*
+ * AMD MP2 I2C Platform Driver
+ *
+ * Authors: Nehal Bakulchandra Shah <Nehal-bakulchandra.shah@amd.com>
+ *          Elie Morisse <syniurge@gmail.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/i2c.h>
+#include <linux/platform_device.h>
+#include <linux/acpi.h>
+#include <linux/delay.h>
+
+#include "i2c-amd-pci-mp2.h"
+#define DRIVER_NAME "i2c-amd-plat-mp2"
+
+#define AMD_MP2_I2C_MAX_RW_LENGTH ((1 << 12) - 1)
+#define AMD_I2C_TIMEOUT (msecs_to_jiffies(250))
+
+/**
+ * struct amd_i2c_dev - MP2 bus/i2c adapter context
+ * @i2c_common: shared context with the MP2 pci driver
+ * @pdev: platform driver node
+ * @adapter: i2c adapter
+ * @xfer_lock: xfer lock
+ * @completion: xfer completion object
+ */
+struct amd_i2c_dev {
+	struct amd_i2c_common i2c_common;
+	struct platform_device *pdev;
+	struct i2c_adapter adapter;
+	struct mutex xfer_lock;
+	struct completion msg_complete;
+	struct i2c_msg *msg_buf;
+	bool is_configured;
+};
+
+static const struct i2c_adapter_quirks amd_i2c_dev_quirks = {
+	.max_read_len = AMD_MP2_I2C_MAX_RW_LENGTH,
+	.max_write_len = AMD_MP2_I2C_MAX_RW_LENGTH,
+};
+
+#define amd_i2c_dev_common(__common) \
+	container_of(__common, struct amd_i2c_dev, i2c_common)
+
+static int i2c_amd_read_completion(union i2c_event *event)
+{
+	struct amd_i2c_common *i2c_common = event_amd_i2c_common(event);
+	struct amd_i2c_dev *i2c_dev = amd_i2c_dev_common(i2c_common);
+
+	if (event->r.status == i2c_readcomplete_event)
+		dev_dbg(&i2c_dev->pdev->dev, "%s readdata:%*ph\n",
+			__func__, event->r.length,
+			i2c_common->rw_cfg.buf);
+
+	complete(&i2c_dev->msg_complete);
+
+	return 0;
+}
+
+static int i2c_amd_write_completion(union i2c_event *event)
+{
+	struct amd_i2c_common *i2c_common = event_amd_i2c_common(event);
+	struct amd_i2c_dev *i2c_dev = amd_i2c_dev_common(i2c_common);
+
+	complete(&i2c_dev->msg_complete);
+
+	return 0;
+}
+
+static int i2c_amd_connect_completion(union i2c_event *event)
+{
+	struct amd_i2c_common *i2c_common = event_amd_i2c_common(event);
+	struct amd_i2c_dev *i2c_dev = amd_i2c_dev_common(i2c_common);
+
+	complete(&i2c_dev->msg_complete);
+
+	return 0;
+}
+
+static const struct amd_i2c_pci_ops data_handler = {
+		.read_complete = i2c_amd_read_completion,
+		.write_complete = i2c_amd_write_completion,
+		.connect_complete = i2c_amd_connect_completion,
+};
+
+static int i2c_amd_pci_configure(struct amd_i2c_dev *i2c_dev)
+{
+	struct amd_i2c_common *i2c_common = &i2c_dev->i2c_common;
+
+	amd_i2c_register_cb(i2c_common->mp2_dev, i2c_common);
+	i2c_common->ops = &data_handler;
+
+	return 0;
+}
+
+static int i2c_amd_pci_xconnect(struct amd_i2c_dev *i2c_dev, bool enable)
+{
+	struct amd_i2c_common *i2c_common = &i2c_dev->i2c_common;
+	unsigned long timeout;
+
+	reinit_completion(&i2c_dev->msg_complete);
+	amd_mp2_connect(i2c_common, enable);
+	timeout = wait_for_completion_timeout(&i2c_dev->msg_complete,
+					      AMD_I2C_TIMEOUT);
+	if (timeout == 0) {
+		dev_err(&i2c_dev->pdev->dev,
+			"i2c connection timed out\n");
+		mutex_unlock(&i2c_dev->xfer_lock);
+		return -ETIMEDOUT;
+	}
+
+	return 0;
+}
+
+static int i2c_amd_xfer_msg(struct amd_i2c_dev *i2c_dev, struct i2c_msg *pmsg)
+{
+	struct amd_i2c_common *i2c_common = &i2c_dev->i2c_common;
+	unsigned long timeout;
+	bool is_read = pmsg->flags & I2C_M_RD;
+
+	reinit_completion(&i2c_dev->msg_complete);
+
+	i2c_common->rw_cfg.slave_addr = pmsg->addr;
+	i2c_common->rw_cfg.buf = (u32 *)pmsg->buf;
+	i2c_common->rw_cfg.length = pmsg->len;
+	i2c_dev->msg_buf = pmsg;
+
+	if (is_read)
+		amd_mp2_read(i2c_common);
+	else
+		amd_mp2_write(i2c_common);
+
+	timeout = wait_for_completion_timeout
+		(&i2c_dev->msg_complete, AMD_I2C_TIMEOUT);
+	if (timeout == 0) {
+		dev_err(&i2c_dev->pdev->dev,
+			"i2c %s timed out\n",
+			is_read ? "read" : "write");
+		return -ETIMEDOUT;
+	}
+
+	return 0;
+}
+
+static int i2c_amd_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
+{
+	struct amd_i2c_dev *dev = i2c_get_adapdata(adap);
+	int i;
+	struct i2c_msg *pmsg;
+	int err;
+
+	mutex_lock(&dev->xfer_lock);
+
+	if (dev->is_configured == 0) {
+		i2c_amd_pci_configure(dev);
+		i2c_amd_pci_xconnect(dev, true);
+		dev->is_configured = 1;
+	}
+
+	for (i = 0; i < num; i++) {
+		pmsg = &msgs[i];
+		err = i2c_amd_xfer_msg(dev, pmsg);
+		if (err)
+			break;
+	}
+
+	mutex_unlock(&dev->xfer_lock);
+
+	if (err)
+		return err;
+	return num;
+}
+
+static u32 i2c_amd_func(struct i2c_adapter *a)
+{
+	return I2C_FUNC_I2C;
+}
+
+static const struct i2c_algorithm i2c_amd_algorithm = {
+	.master_xfer = i2c_amd_xfer,
+	.functionality = i2c_amd_func,
+};
+
+static enum speed_enum i2c_amd_get_bus_speed(struct platform_device *pdev)
+{
+	u32 acpi_speed;
+	int i;
+	static const u32 supported_speeds[] = {
+		0, 100000, 400000, 1000000, 1400000, 3400000
+	};
+
+	acpi_speed = i2c_acpi_find_bus_speed(&pdev->dev);
+	/* round down to the lowest standard speed */
+	for (i = 1; i < ARRAY_SIZE(supported_speeds); i++) {
+		if (acpi_speed < supported_speeds[i])
+			break;
+	}
+	acpi_speed = supported_speeds[i - 1];
+
+	switch (acpi_speed) {
+	case 100000:
+		return speed100k;
+	case 400000:
+		return speed400k;
+	case 1000000:
+		return speed1000k;
+	case 1400000:
+		return speed1400k;
+	case 3400000:
+		return speed3400k;
+	default:
+		return speed400k;
+	}
+}
+
+static struct device *i2c_amd_acpi_get_first_phys_node(struct acpi_device *adev)
+{
+	const struct acpi_device_physical_node *node;
+
+	if (list_empty(&adev->physical_node_list))
+		return NULL;
+
+	node = list_first_entry(&adev->physical_node_list,
+				struct acpi_device_physical_node, node);
+	return node->dev;
+}
+
+/*
+ * Assume that the first device listed by the _DEP method is the parent
+ * MP2 device
+ */
+static struct pci_dev *i2c_amd_find_pci_parent(struct acpi_device *adev)
+{
+	struct acpi_device *parent_adev;
+	struct device *phys_dev;
+	struct acpi_handle_list dep_devices;
+	acpi_status status;
+
+	if (!acpi_has_method(adev->handle, "_DEP"))
+		return NULL;
+
+	status = acpi_evaluate_reference(adev->handle, "_DEP", NULL,
+					 &dep_devices);
+	if (ACPI_FAILURE(status) || !dep_devices.count)
+		return NULL;
+
+	if (acpi_bus_get_device(dep_devices.handles[0], &parent_adev))
+		return NULL;
+	phys_dev = i2c_amd_acpi_get_first_phys_node(parent_adev);
+
+	if (!dev_is_pci(phys_dev))
+		return NULL;
+	return to_pci_dev(phys_dev);
+}
+
+static int i2c_amd_probe(struct platform_device *pdev)
+{
+	int ret;
+	struct amd_i2c_dev *i2c_dev;
+	struct device *dev = &pdev->dev;
+	acpi_handle handle = ACPI_HANDLE(&pdev->dev);
+	struct acpi_device *adev;
+	struct pci_dev *parent_candidate = NULL;
+
+	i2c_dev = devm_kzalloc(dev, sizeof(*i2c_dev), GFP_KERNEL);
+	if (!i2c_dev)
+		return -ENOMEM;
+
+	i2c_dev->pdev = pdev;
+
+	if (!acpi_bus_get_device(handle, &adev)) {
+		const char *uid = adev->pnp.unique_id;
+
+		if (!uid) {
+			dev_err(&pdev->dev, "missing UID/bus id!\n");
+			return -EINVAL;
+		}
+
+		if (strcmp(uid, "0") == 0) {
+			i2c_dev->i2c_common.bus_id = 0;
+		} else if (strcmp(uid, "1") == 0) {
+			i2c_dev->i2c_common.bus_id = 1;
+		} else {
+			dev_err(&pdev->dev,
+				"incorrect UID/bus id \"%s\"!\n", uid);
+			return -EINVAL;
+		}
+
+		dev_dbg(&pdev->dev, "bus id is %u\n",
+			i2c_dev->i2c_common.bus_id);
+
+		i2c_dev->i2c_common.i2c_speed = i2c_amd_get_bus_speed(pdev);
+	} else {
+		i2c_dev->i2c_common.i2c_speed = speed400k;
+	}
+
+	/* setup i2c adapter description */
+	i2c_dev->adapter.owner = THIS_MODULE;
+	i2c_dev->adapter.algo = &i2c_amd_algorithm;
+	i2c_dev->adapter.quirks = &amd_i2c_dev_quirks;
+	i2c_dev->adapter.dev.parent = dev;
+	i2c_dev->adapter.algo_data = i2c_dev;
+	ACPI_COMPANION_SET(&i2c_dev->adapter.dev, ACPI_COMPANION(&pdev->dev));
+	i2c_dev->adapter.dev.of_node = dev->of_node;
+	snprintf(i2c_dev->adapter.name, sizeof(i2c_dev->adapter.name), "%s-%s",
+		 "i2c_dev-i2c", dev_name(pdev->dev.parent));
+
+	if (adev)
+		parent_candidate = i2c_amd_find_pci_parent(adev);
+	i2c_dev->i2c_common.mp2_dev = amd_mp2_find_device(parent_candidate);
+	if (!i2c_dev->i2c_common.mp2_dev) {
+		dev_err(&pdev->dev,
+			"%s Could not find MP2 PCI device for i2c adapter\n",
+		       __func__);
+		return -EINVAL;
+	}
+
+	platform_set_drvdata(pdev, i2c_dev);
+
+	i2c_set_adapdata(&i2c_dev->adapter, i2c_dev);
+
+	init_completion(&i2c_dev->msg_complete);
+	mutex_init(&i2c_dev->xfer_lock);
+
+	/* and finally attach to i2c layer */
+	ret = i2c_add_adapter(&i2c_dev->adapter);
+
+	if (ret < 0)
+		dev_err(&pdev->dev, "i2c add adapter failed = %d\n", ret);
+
+	return ret;
+}
+
+static int i2c_amd_remove(struct platform_device *pdev)
+{
+	struct amd_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
+	struct amd_i2c_common *i2c_common = &i2c_dev->i2c_common;
+
+	i2c_amd_pci_xconnect(i2c_dev, false);
+
+	amd_i2c_unregister_cb(i2c_common->mp2_dev, i2c_common);
+	i2c_del_adapter(&i2c_dev->adapter);
+
+	return 0;
+}
+
+static const struct acpi_device_id i2c_amd_acpi_match[] = {
+		{ "AMDI0011" },
+		{ },
+};
+MODULE_DEVICE_TABLE(acpi, i2c_amd_acpi_match);
+
+static struct platform_driver amd_i2c_plat_driver = {
+		.probe = i2c_amd_probe,
+		.remove = i2c_amd_remove,
+		.driver = {
+				.name = "i2c_amd_plat_mp2",
+				.acpi_match_table = ACPI_PTR
+						(i2c_amd_acpi_match),
+		},
+};
+
+module_platform_driver(amd_i2c_plat_driver);
+
+MODULE_DESCRIPTION("AMD MP2 I2C Platform Driver");
+MODULE_AUTHOR("Nehal Shah <nehal-bakulchandra.shah@amd.com>");
+MODULE_AUTHOR("Elie Morisse <syniurge@gmail.com>");
+MODULE_LICENSE("Dual BSD/GPL");
-- 
2.17.1


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