Hi Lee,

On 7/27/2018 1:26 AM, Lee Jones wrote:

On Mon, 23 Jul 2018, Jae Hyun Yoo wrote:

quoted

This commit adds PECI client MFD driver.

Signed-off-by: Jae Hyun Yoo <redacted>
Cc: Lee Jones <redacted>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Andrew Jeffery <redacted>
Cc: James Feist <redacted>
Cc: Jason M Biils <redacted>
Cc: Joel Stanley <joel@jms.id.au>
Cc: Vernon Mauery <redacted>
---
  drivers/mfd/Kconfig                   |  14 ++
  drivers/mfd/Makefile                  |   1 +
  drivers/mfd/intel-peci-client.c       | 182 ++++++++++++++++++++++++++
  include/linux/mfd/intel-peci-client.h |  81 ++++++++++++
  4 files changed, 278 insertions(+)
  create mode 100644 drivers/mfd/intel-peci-client.c
  create mode 100644 include/linux/mfd/intel-peci-client.h

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index f3fa516011ec..e38b591479d4 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig

@@ -595,6 +595,20 @@ config MFD_INTEL_MSIC
  	  Passage) chip. This chip embeds audio, battery, GPIO, etc.
  	  devices used in Intel Medfield platforms.
  
+config MFD_INTEL_PECI_CLIENT
+	bool "Intel PECI client"
+	depends on (PECI || COMPILE_TEST)
+	select MFD_CORE
+	help
+	  If you say yes to this option, support will be included for the
+	  multi-funtional Intel PECI (Platform Environment Control Interface)
+	  client. PECI is a one-wire bus interface that provides a communication
+	  channel from PECI clients in Intel processors and chipset components
+	  to external monitoring or control devices.
+
+	  Additional drivers must be enabled in order to use the functionality
+	  of the device.
+
  config MFD_IPAQ_MICRO
  	bool "Atmel Micro ASIC (iPAQ h3100/h3600/h3700) Support"
  	depends on SA1100_H3100 || SA1100_H3600

diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index 2852a6042ecf..29e2cacc58bd 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile

@@ -203,6 +203,7 @@ obj-$(CONFIG_MFD_INTEL_LPSS)	+= intel-lpss.o
  obj-$(CONFIG_MFD_INTEL_LPSS_PCI)	+= intel-lpss-pci.o
  obj-$(CONFIG_MFD_INTEL_LPSS_ACPI)	+= intel-lpss-acpi.o
  obj-$(CONFIG_MFD_INTEL_MSIC)	+= intel_msic.o
+obj-$(CONFIG_MFD_INTEL_PECI_CLIENT)	+= intel-peci-client.o
  obj-$(CONFIG_MFD_PALMAS)	+= palmas.o
  obj-$(CONFIG_MFD_VIPERBOARD)    += viperboard.o
  obj-$(CONFIG_MFD_RC5T583)	+= rc5t583.o rc5t583-irq.o

diff --git a/drivers/mfd/intel-peci-client.c b/drivers/mfd/intel-peci-client.c
new file mode 100644
index 000000000000..d7702cf1ea50
--- /dev/null
+++ b/drivers/mfd/intel-peci-client.c

@@ -0,0 +1,182 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2018 Intel Corporation
+
+#include <linux/bitfield.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/intel-peci-client.h>
+#include <linux/module.h>
+#include <linux/peci.h>
+#include <linux/of_device.h>
+
+enum cpu_gens {
+	CPU_GEN_HSX = 0, /* Haswell Xeon */
+	CPU_GEN_BRX,     /* Broadwell Xeon */
+	CPU_GEN_SKX,     /* Skylake Xeon */
+};
+
+static struct mfd_cell peci_functions[] = {
+	{
+		.name = "peci-cputemp",
+		.of_compatible = "intel,peci-cputemp",
+	},
+	{
+		.name = "peci-dimmtemp",
+		.of_compatible = "intel,peci-dimmtemp",
+	},
+};

The more I look at this driver, the less I think it fits into MFD.

What's stopping you from registering these devices directly from DT?

Because DT doesn't allow 2 nodes at the same address so Rob suggested
MFD for this case.

Thanks,

Jae