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SubjectRe: [PATCH v7] i2c: Add PCI and platform drivers for the AMD MP2 I2C controller
[+cc Rafael, Len, linux-acpi]

On Sat, Oct 27, 2018 at 12:09:10PM -0300, Elie Morisse wrote:
> 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.

I'm dubious about this two-driver structure. If I understand
correctly (and it's very possible that I don't), the PCI driver
(amd_mp2_pci_probe()) is the real owner of the i2c adapter: it
claims the PCI device, claims its BARs, and requests an IRQ.

The i2c_amd_probe() code *looks* like a platform driver that claims
AMDI0011 devices from the ACPI namespace, but I don't think it's
really a driver. It looks like it exists mainly to extract some
information (bus speed and maybe a bus number?) from the namespace,
then to call i2c_add_adapter().

It looks like i2c_amd_probe() must run *after* amd_mp2_pci_probe(),
but there's no way to really enforce that ordering.

And i2c-amd-plat-mp2 contains the i2c_amd_algorithm functions, which
operate on the PCI device, which requires exported interfaces
(amd_mp2_read(), amd_mp2_write()) that are implemented in the PCI
driver but called from the platform part.

It seems like there should be a way to put the ACPI lookups into
i2c-amd-pci-mp2 so there's only one driver.

I only have a couple trivial comments below but I'm not trimming my
response so the ACPI folks can see the whole context.

> 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);

You can use %pR on pci_dev->resource[2]. That uses the conventional
format (same as used by the PCI core).

> +
> + 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;

There's nothing to clean up at this point, so just emit the message
and return directly:

if (!privdata) {
dev_err(&pci_dev->dev, "Memory Allocation Failed\n");
return -ENOMEM;
}

> + }
> +
> + 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);
Several other callers of acpi_evaluate_reference() do call
acpi_has_method() first, but I'm pretty sure that's not necessary. If
_DEP doesn't exist, acpi_evaluate_reference() should return an error
itself.

_DEP is for operation region dependencies. I don't know enough about
ACPI to know why you're using it to find the PCI device related to an
ACPI device. That doesn't really seem like an op region thing.

> + 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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