From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lee Jones Subject: Re: [PATCH v7 08/12] mfd: intel-peci-client: Add PECI client MFD driver Date: Tue, 31 Jul 2018 08:01:17 +0100 Message-ID: <20180731070117.GE4662@dell> References: <20180723214751.1733-1-jae.hyun.yoo@linux.intel.com> <20180723214751.1733-9-jae.hyun.yoo@linux.intel.com> <20180727082611.GE4628@dell> <7ab43253-1154-6e2f-b216-69b0d44b470a@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Return-path: Content-Disposition: inline In-Reply-To: <7ab43253-1154-6e2f-b216-69b0d44b470a@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org To: Jae Hyun Yoo Cc: Rob Herring , Jean Delvare , Guenter Roeck , Mark Rutland , Joel Stanley , Andrew Jeffery , Jonathan Corbet , Greg Kroah-Hartman , Gustavo Pimentel , Kishon Vijay Abraham I , Lorenzo Pieralisi , darrick.wong@oracle.com, sandeen@redhat.com, Arnd Bergmann , Wu Hao , kusumi.tomohiro@gmail.com, bryantly@linux.vnet.ibm.com, fbarrat@linux.vnet.ibm.com, David Miller , Mauro Carvalho Chehab , Andrew Morton , Randy Dunlap List-Id: devicetree@vger.kernel.org On Mon, 30 Jul 2018, Jae Hyun Yoo wrote: > Hi Rob, > > On 7/30/2018 3:10 PM, Rob Herring wrote: > > On Fri, Jul 27, 2018 at 11:36 AM Jae Hyun Yoo > > wrote: > > > > > > Hi Lee, > > > > > > On 7/27/2018 1:26 AM, Lee Jones wrote: > > > > On Mon, 23 Jul 2018, Jae Hyun Yoo wrote: > > > > > > > > > This commit adds PECI client MFD driver. > > > > > > > > > > Signed-off-by: Jae Hyun Yoo > > > > > Cc: Lee Jones > > > > > Cc: Rob Herring > > > > > Cc: Andrew Jeffery > > > > > Cc: James Feist > > > > > Cc: Jason M Biils > > > > > Cc: Joel Stanley > > > > > Cc: Vernon Mauery > > > > > --- > > > > > 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 > > > > > +#include > > > > > +#include > > > > > +#include > > > > > +#include > > > > > +#include > > > > > + > > > > > +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. > > > > Only after I first suggested you create cpu and dimm sensors from a > > single hwmon driver. Perhaps you should figure out how to fix the > > problem with delayed registration. Perhaps you can register the > > sensor, but just delay returning actual data until it is ready. > > > > The actual reason why I divided the single hwmon driver into two is for > using recommended hwmon API set which doesn't allow incremental > creation of sysfs attributes at run time - using of > 'devm_hwmon_device_register_with_info' is suggested by Guenter instead > of using other deprecated APIs. > > The reason why the delayed registration is needed is, BMC kernel cannot > know how many DIMM are installed in remote machine before the machine > completing memory training and testing in POST. So dimm temp driver > cannot create hwmon attributes in advance. > > My thought is, this way is the best to address these requirements. As I've previously explained, I do not think this is a good fit for MFD. Since this whole PECI piece is a bit, let's say 'niche', perhaps it's better to contain the client within the PECI subsystem too. You can then use the platform_device_add() API to register devices as and when required. -- Lee Jones [李琼斯] Linaro Services Technical Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog