SlideShare a Scribd company logo
1 of 11
Download to read offline
Common clock Device Tree bindings
Mike Turquette, 2013-10-29
connect.linaro.org
● Number of clock driver changes has increased
● Some of the more active platforms are having lots of merge
conflicts amongst their own clock driver changes
● I’m happy to take pull requests, instead of cobbling it all together
○ After requisite patch review
● Also might be good to have one owner/maintainer for each
platform’s clock driver that marshalls all patches together
Quick note on pull requests
connect.linaro.org
● The primary benefit that DT brings to clocks is linking clock
phandles to consumer devices
● This has been integrated with clk_get
● If DT does absolutely nothing else for clocks, that’s OK by me
Device Tree as clkdev
connect.linaro.org
A “clock controller” node in DT has various clock inputs and various
clock outputs. #clock-cells is 1. Use a phandle + index to get a clock.
● Documentation/devicetree/bindings/clock/exynos5250-clock.txt
● arch/arm/boot/dts/exynos5250.dtsi
A “per-clock” node corresponds to a single clock entity, often with
verbose clock data. #clock-cells is 0. Use just the phandle to get it.
● http://www.spinics.net/lists/arm-kernel/msg282479.html
Terminology
connect.linaro.org
Two approaches - each at opposite ends of the spectrum
● Model a clock controller as a node in DTS
○ Least controversial
○ Little to no hardware description, no per-clock data in DTS
○ Clocks are enumerated in the binding definition
○ Only purpose is to link clock phandles to clock consumer nodes
○ Sometimes referred to as the “clock mapping” approach
○ Results in lots of struct clk object
DT clock bindings
connect.linaro.org
● Model per-clock data in DTS
○ Most controversial
○ There should be no clock data in the kernel source at all
○ Benefit is moving data out of the kernel - makes Linus happy?
○ Only used in some rare cases - fixed-rate clock, OMAP
○ Results in a single struct clk object
DT clock bindings, cont’d
connect.linaro.org
● Off-SoC clocks such as oscillators
○ Things that change on a per-board basis
● Intermediate solution for new platforms
○ If bootloader enables clocks then it is possible to use fixed-rate clocks
defined in DTS as placeholder clocks
○ This is helpful for drivers that expect to get clocks and know their rate
■ Analogous to a dummy regulator
○ Eventually replace this data in DTS with the appropriate clock controller node
binding
Why model clock data in DTS?
connect.linaro.org
● The only reason is to move 100% of clock data out of the kernel
source
○ Flamebait: Is that what Linus wants in The Future?
● If we cannot remove 100% of the static clock data from the kernel
then do not bother putting any of it in DTS
○ Just use a clock controller mapping scheme
Why model clock data in DTS?
connect.linaro.org
● Easy enough for off-chip fixed-rate crystals and oscillators
● What about complex on-SoC clocks?
○ We need to model register-level data such as bitmasks
○ In some cases, create one node per clock
Modeling clock data in DTS
connect.linaro.org
● Please use the clock-names property to list the input name for the
clock with respect to the consuming node
● Not the name of the clock output name from the data sheet!
Misc. note on clock-names
More about Linaro: http://www.linaro.org/about/
More about Linaro engineering: http://www.linaro.org/engineering/
How to join: http://www.linaro.org/about/how-to-join
Linaro members: www.linaro.org/members
connect.linaro.org

More Related Content

Viewers also liked

CIS 2015- IoT? The ‘I’ needs to be ‘Identity’- Paul Madsen
CIS 2015- IoT? The ‘I’ needs to be ‘Identity’- Paul MadsenCIS 2015- IoT? The ‘I’ needs to be ‘Identity’- Paul Madsen
CIS 2015- IoT? The ‘I’ needs to be ‘Identity’- Paul MadsenCloudIDSummit
 
Application Delivery Networking
Application Delivery NetworkingApplication Delivery Networking
Application Delivery Networkingrjain51
 
Optical fiber communication system Important paper
Optical fiber communication system Important paper Optical fiber communication system Important paper
Optical fiber communication system Important paper Dawood Aqlan
 
Introduction to optical fiber communication
Introduction to optical fiber communicationIntroduction to optical fiber communication
Introduction to optical fiber communicationVijendra Kumar Prajapati
 
Optical fiber communication
Optical fiber communicationOptical fiber communication
Optical fiber communicationRaj Kumar Morya
 
Business Drivers and Challenges of Cloud Computing and Social Networking Appl...
Business Drivers and Challenges of Cloud Computing and Social Networking Appl...Business Drivers and Challenges of Cloud Computing and Social Networking Appl...
Business Drivers and Challenges of Cloud Computing and Social Networking Appl...M Biro
 
Optical fiber communication-Presented by Kiran Devkota
Optical fiber communication-Presented by Kiran DevkotaOptical fiber communication-Presented by Kiran Devkota
Optical fiber communication-Presented by Kiran DevkotaSujit Jha
 
optical fiber communication..
optical fiber communication..optical fiber communication..
optical fiber communication..Debanshu Ghosh
 
Optical Fiber communication
Optical Fiber communicationOptical Fiber communication
Optical Fiber communicationEklavya Singh
 
Optical communication and Equipments
Optical communication and EquipmentsOptical communication and Equipments
Optical communication and EquipmentsRavi Bhasker
 
Optical Fiber Communication
Optical Fiber Communication Optical Fiber Communication
Optical Fiber Communication Nikhil Kumar
 
Govind agrawal's fiber optical communication
Govind agrawal's fiber optical  communicationGovind agrawal's fiber optical  communication
Govind agrawal's fiber optical communicationsmartknight
 
Optical Fiber Communication | Report
Optical Fiber Communication | ReportOptical Fiber Communication | Report
Optical Fiber Communication | ReportVanhishikha Bhargava
 
Industrial training presentation
Industrial training presentationIndustrial training presentation
Industrial training presentationisamhasbi
 
Industrial training ppt.
Industrial training ppt.Industrial training ppt.
Industrial training ppt.Tarun Sharma
 
optical fibre ppt for download visit http://nowcracktheworld.blogspot.in/
optical fibre  ppt for download visit http://nowcracktheworld.blogspot.in/optical fibre  ppt for download visit http://nowcracktheworld.blogspot.in/
optical fibre ppt for download visit http://nowcracktheworld.blogspot.in/Ram Niwas Bajiya
 

Viewers also liked (18)

CIS 2015- IoT? The ‘I’ needs to be ‘Identity’- Paul Madsen
CIS 2015- IoT? The ‘I’ needs to be ‘Identity’- Paul MadsenCIS 2015- IoT? The ‘I’ needs to be ‘Identity’- Paul Madsen
CIS 2015- IoT? The ‘I’ needs to be ‘Identity’- Paul Madsen
 
Application Delivery Networking
Application Delivery NetworkingApplication Delivery Networking
Application Delivery Networking
 
Optical fiber communication system Important paper
Optical fiber communication system Important paper Optical fiber communication system Important paper
Optical fiber communication system Important paper
 
Phase change-materials-networking-applications
Phase change-materials-networking-applicationsPhase change-materials-networking-applications
Phase change-materials-networking-applications
 
Introduction to optical fiber communication
Introduction to optical fiber communicationIntroduction to optical fiber communication
Introduction to optical fiber communication
 
Optical fiber communication
Optical fiber communicationOptical fiber communication
Optical fiber communication
 
Business Drivers and Challenges of Cloud Computing and Social Networking Appl...
Business Drivers and Challenges of Cloud Computing and Social Networking Appl...Business Drivers and Challenges of Cloud Computing and Social Networking Appl...
Business Drivers and Challenges of Cloud Computing and Social Networking Appl...
 
Optical fiber communication-Presented by Kiran Devkota
Optical fiber communication-Presented by Kiran DevkotaOptical fiber communication-Presented by Kiran Devkota
Optical fiber communication-Presented by Kiran Devkota
 
optical fiber communication..
optical fiber communication..optical fiber communication..
optical fiber communication..
 
Optical Fiber communication
Optical Fiber communicationOptical Fiber communication
Optical Fiber communication
 
Optical communication and Equipments
Optical communication and EquipmentsOptical communication and Equipments
Optical communication and Equipments
 
Optical Fiber Communication
Optical Fiber Communication Optical Fiber Communication
Optical Fiber Communication
 
Govind agrawal's fiber optical communication
Govind agrawal's fiber optical  communicationGovind agrawal's fiber optical  communication
Govind agrawal's fiber optical communication
 
Optical Fiber Communication | Report
Optical Fiber Communication | ReportOptical Fiber Communication | Report
Optical Fiber Communication | Report
 
Industrial training presentation
Industrial training presentationIndustrial training presentation
Industrial training presentation
 
Industrial training ppt.
Industrial training ppt.Industrial training ppt.
Industrial training ppt.
 
OPTICAL FIBER COMMUNICATION PPT
OPTICAL FIBER COMMUNICATION PPTOPTICAL FIBER COMMUNICATION PPT
OPTICAL FIBER COMMUNICATION PPT
 
optical fibre ppt for download visit http://nowcracktheworld.blogspot.in/
optical fibre  ppt for download visit http://nowcracktheworld.blogspot.in/optical fibre  ppt for download visit http://nowcracktheworld.blogspot.in/
optical fibre ppt for download visit http://nowcracktheworld.blogspot.in/
 

More from Linaro

Deep Learning Neural Network Acceleration at the Edge - Andrea Gallo
Deep Learning Neural Network Acceleration at the Edge - Andrea GalloDeep Learning Neural Network Acceleration at the Edge - Andrea Gallo
Deep Learning Neural Network Acceleration at the Edge - Andrea GalloLinaro
 
Arm Architecture HPC Workshop Santa Clara 2018 - Kanta Vekaria
Arm Architecture HPC Workshop Santa Clara 2018 - Kanta VekariaArm Architecture HPC Workshop Santa Clara 2018 - Kanta Vekaria
Arm Architecture HPC Workshop Santa Clara 2018 - Kanta VekariaLinaro
 
Huawei’s requirements for the ARM based HPC solution readiness - Joshua Mora
Huawei’s requirements for the ARM based HPC solution readiness - Joshua MoraHuawei’s requirements for the ARM based HPC solution readiness - Joshua Mora
Huawei’s requirements for the ARM based HPC solution readiness - Joshua MoraLinaro
 
Bud17 113: distribution ci using qemu and open qa
Bud17 113: distribution ci using qemu and open qaBud17 113: distribution ci using qemu and open qa
Bud17 113: distribution ci using qemu and open qaLinaro
 
OpenHPC Automation with Ansible - Renato Golin - Linaro Arm HPC Workshop 2018
OpenHPC Automation with Ansible - Renato Golin - Linaro Arm HPC Workshop 2018OpenHPC Automation with Ansible - Renato Golin - Linaro Arm HPC Workshop 2018
OpenHPC Automation with Ansible - Renato Golin - Linaro Arm HPC Workshop 2018Linaro
 
HPC network stack on ARM - Linaro HPC Workshop 2018
HPC network stack on ARM - Linaro HPC Workshop 2018HPC network stack on ARM - Linaro HPC Workshop 2018
HPC network stack on ARM - Linaro HPC Workshop 2018Linaro
 
It just keeps getting better - SUSE enablement for Arm - Linaro HPC Workshop ...
It just keeps getting better - SUSE enablement for Arm - Linaro HPC Workshop ...It just keeps getting better - SUSE enablement for Arm - Linaro HPC Workshop ...
It just keeps getting better - SUSE enablement for Arm - Linaro HPC Workshop ...Linaro
 
Intelligent Interconnect Architecture to Enable Next Generation HPC - Linaro ...
Intelligent Interconnect Architecture to Enable Next Generation HPC - Linaro ...Intelligent Interconnect Architecture to Enable Next Generation HPC - Linaro ...
Intelligent Interconnect Architecture to Enable Next Generation HPC - Linaro ...Linaro
 
Yutaka Ishikawa - Post-K and Arm HPC Ecosystem - Linaro Arm HPC Workshop Sant...
Yutaka Ishikawa - Post-K and Arm HPC Ecosystem - Linaro Arm HPC Workshop Sant...Yutaka Ishikawa - Post-K and Arm HPC Ecosystem - Linaro Arm HPC Workshop Sant...
Yutaka Ishikawa - Post-K and Arm HPC Ecosystem - Linaro Arm HPC Workshop Sant...Linaro
 
Andrew J Younge - Vanguard Astra - Petascale Arm Platform for U.S. DOE/ASC Su...
Andrew J Younge - Vanguard Astra - Petascale Arm Platform for U.S. DOE/ASC Su...Andrew J Younge - Vanguard Astra - Petascale Arm Platform for U.S. DOE/ASC Su...
Andrew J Younge - Vanguard Astra - Petascale Arm Platform for U.S. DOE/ASC Su...Linaro
 
HKG18-501 - EAS on Common Kernel 4.14 and getting (much) closer to mainline
HKG18-501 - EAS on Common Kernel 4.14 and getting (much) closer to mainlineHKG18-501 - EAS on Common Kernel 4.14 and getting (much) closer to mainline
HKG18-501 - EAS on Common Kernel 4.14 and getting (much) closer to mainlineLinaro
 
HKG18-100K1 - George Grey: Opening Keynote
HKG18-100K1 - George Grey: Opening KeynoteHKG18-100K1 - George Grey: Opening Keynote
HKG18-100K1 - George Grey: Opening KeynoteLinaro
 
HKG18-318 - OpenAMP Workshop
HKG18-318 - OpenAMP WorkshopHKG18-318 - OpenAMP Workshop
HKG18-318 - OpenAMP WorkshopLinaro
 
HKG18-501 - EAS on Common Kernel 4.14 and getting (much) closer to mainline
HKG18-501 - EAS on Common Kernel 4.14 and getting (much) closer to mainlineHKG18-501 - EAS on Common Kernel 4.14 and getting (much) closer to mainline
HKG18-501 - EAS on Common Kernel 4.14 and getting (much) closer to mainlineLinaro
 
HKG18-315 - Why the ecosystem is a wonderful thing, warts and all
HKG18-315 - Why the ecosystem is a wonderful thing, warts and allHKG18-315 - Why the ecosystem is a wonderful thing, warts and all
HKG18-315 - Why the ecosystem is a wonderful thing, warts and allLinaro
 
HKG18- 115 - Partitioning ARM Systems with the Jailhouse Hypervisor
HKG18- 115 - Partitioning ARM Systems with the Jailhouse HypervisorHKG18- 115 - Partitioning ARM Systems with the Jailhouse Hypervisor
HKG18- 115 - Partitioning ARM Systems with the Jailhouse HypervisorLinaro
 
HKG18-TR08 - Upstreaming SVE in QEMU
HKG18-TR08 - Upstreaming SVE in QEMUHKG18-TR08 - Upstreaming SVE in QEMU
HKG18-TR08 - Upstreaming SVE in QEMULinaro
 
HKG18-113- Secure Data Path work with i.MX8M
HKG18-113- Secure Data Path work with i.MX8MHKG18-113- Secure Data Path work with i.MX8M
HKG18-113- Secure Data Path work with i.MX8MLinaro
 
HKG18-120 - Devicetree Schema Documentation and Validation
HKG18-120 - Devicetree Schema Documentation and Validation HKG18-120 - Devicetree Schema Documentation and Validation
HKG18-120 - Devicetree Schema Documentation and Validation Linaro
 
HKG18-223 - Trusted FirmwareM: Trusted boot
HKG18-223 - Trusted FirmwareM: Trusted bootHKG18-223 - Trusted FirmwareM: Trusted boot
HKG18-223 - Trusted FirmwareM: Trusted bootLinaro
 

More from Linaro (20)

Deep Learning Neural Network Acceleration at the Edge - Andrea Gallo
Deep Learning Neural Network Acceleration at the Edge - Andrea GalloDeep Learning Neural Network Acceleration at the Edge - Andrea Gallo
Deep Learning Neural Network Acceleration at the Edge - Andrea Gallo
 
Arm Architecture HPC Workshop Santa Clara 2018 - Kanta Vekaria
Arm Architecture HPC Workshop Santa Clara 2018 - Kanta VekariaArm Architecture HPC Workshop Santa Clara 2018 - Kanta Vekaria
Arm Architecture HPC Workshop Santa Clara 2018 - Kanta Vekaria
 
Huawei’s requirements for the ARM based HPC solution readiness - Joshua Mora
Huawei’s requirements for the ARM based HPC solution readiness - Joshua MoraHuawei’s requirements for the ARM based HPC solution readiness - Joshua Mora
Huawei’s requirements for the ARM based HPC solution readiness - Joshua Mora
 
Bud17 113: distribution ci using qemu and open qa
Bud17 113: distribution ci using qemu and open qaBud17 113: distribution ci using qemu and open qa
Bud17 113: distribution ci using qemu and open qa
 
OpenHPC Automation with Ansible - Renato Golin - Linaro Arm HPC Workshop 2018
OpenHPC Automation with Ansible - Renato Golin - Linaro Arm HPC Workshop 2018OpenHPC Automation with Ansible - Renato Golin - Linaro Arm HPC Workshop 2018
OpenHPC Automation with Ansible - Renato Golin - Linaro Arm HPC Workshop 2018
 
HPC network stack on ARM - Linaro HPC Workshop 2018
HPC network stack on ARM - Linaro HPC Workshop 2018HPC network stack on ARM - Linaro HPC Workshop 2018
HPC network stack on ARM - Linaro HPC Workshop 2018
 
It just keeps getting better - SUSE enablement for Arm - Linaro HPC Workshop ...
It just keeps getting better - SUSE enablement for Arm - Linaro HPC Workshop ...It just keeps getting better - SUSE enablement for Arm - Linaro HPC Workshop ...
It just keeps getting better - SUSE enablement for Arm - Linaro HPC Workshop ...
 
Intelligent Interconnect Architecture to Enable Next Generation HPC - Linaro ...
Intelligent Interconnect Architecture to Enable Next Generation HPC - Linaro ...Intelligent Interconnect Architecture to Enable Next Generation HPC - Linaro ...
Intelligent Interconnect Architecture to Enable Next Generation HPC - Linaro ...
 
Yutaka Ishikawa - Post-K and Arm HPC Ecosystem - Linaro Arm HPC Workshop Sant...
Yutaka Ishikawa - Post-K and Arm HPC Ecosystem - Linaro Arm HPC Workshop Sant...Yutaka Ishikawa - Post-K and Arm HPC Ecosystem - Linaro Arm HPC Workshop Sant...
Yutaka Ishikawa - Post-K and Arm HPC Ecosystem - Linaro Arm HPC Workshop Sant...
 
Andrew J Younge - Vanguard Astra - Petascale Arm Platform for U.S. DOE/ASC Su...
Andrew J Younge - Vanguard Astra - Petascale Arm Platform for U.S. DOE/ASC Su...Andrew J Younge - Vanguard Astra - Petascale Arm Platform for U.S. DOE/ASC Su...
Andrew J Younge - Vanguard Astra - Petascale Arm Platform for U.S. DOE/ASC Su...
 
HKG18-501 - EAS on Common Kernel 4.14 and getting (much) closer to mainline
HKG18-501 - EAS on Common Kernel 4.14 and getting (much) closer to mainlineHKG18-501 - EAS on Common Kernel 4.14 and getting (much) closer to mainline
HKG18-501 - EAS on Common Kernel 4.14 and getting (much) closer to mainline
 
HKG18-100K1 - George Grey: Opening Keynote
HKG18-100K1 - George Grey: Opening KeynoteHKG18-100K1 - George Grey: Opening Keynote
HKG18-100K1 - George Grey: Opening Keynote
 
HKG18-318 - OpenAMP Workshop
HKG18-318 - OpenAMP WorkshopHKG18-318 - OpenAMP Workshop
HKG18-318 - OpenAMP Workshop
 
HKG18-501 - EAS on Common Kernel 4.14 and getting (much) closer to mainline
HKG18-501 - EAS on Common Kernel 4.14 and getting (much) closer to mainlineHKG18-501 - EAS on Common Kernel 4.14 and getting (much) closer to mainline
HKG18-501 - EAS on Common Kernel 4.14 and getting (much) closer to mainline
 
HKG18-315 - Why the ecosystem is a wonderful thing, warts and all
HKG18-315 - Why the ecosystem is a wonderful thing, warts and allHKG18-315 - Why the ecosystem is a wonderful thing, warts and all
HKG18-315 - Why the ecosystem is a wonderful thing, warts and all
 
HKG18- 115 - Partitioning ARM Systems with the Jailhouse Hypervisor
HKG18- 115 - Partitioning ARM Systems with the Jailhouse HypervisorHKG18- 115 - Partitioning ARM Systems with the Jailhouse Hypervisor
HKG18- 115 - Partitioning ARM Systems with the Jailhouse Hypervisor
 
HKG18-TR08 - Upstreaming SVE in QEMU
HKG18-TR08 - Upstreaming SVE in QEMUHKG18-TR08 - Upstreaming SVE in QEMU
HKG18-TR08 - Upstreaming SVE in QEMU
 
HKG18-113- Secure Data Path work with i.MX8M
HKG18-113- Secure Data Path work with i.MX8MHKG18-113- Secure Data Path work with i.MX8M
HKG18-113- Secure Data Path work with i.MX8M
 
HKG18-120 - Devicetree Schema Documentation and Validation
HKG18-120 - Devicetree Schema Documentation and Validation HKG18-120 - Devicetree Schema Documentation and Validation
HKG18-120 - Devicetree Schema Documentation and Validation
 
HKG18-223 - Trusted FirmwareM: Trusted boot
HKG18-223 - Trusted FirmwareM: Trusted bootHKG18-223 - Trusted FirmwareM: Trusted boot
HKG18-223 - Trusted FirmwareM: Trusted boot
 

Recently uploaded

Planetek Italia Srl - Corporate Profile Brochure
Planetek Italia Srl - Corporate Profile BrochurePlanetek Italia Srl - Corporate Profile Brochure
Planetek Italia Srl - Corporate Profile BrochurePlanetek Italia Srl
 
Novo Nordisk's journey in developing an open-source application on Neo4j
Novo Nordisk's journey in developing an open-source application on Neo4jNovo Nordisk's journey in developing an open-source application on Neo4j
Novo Nordisk's journey in developing an open-source application on Neo4jNeo4j
 
My key hands-on projects in Quantum, and QAI
My key hands-on projects in Quantum, and QAIMy key hands-on projects in Quantum, and QAI
My key hands-on projects in Quantum, and QAIVijayananda Mohire
 
Automation Ops Series: Session 2 - Governance for UiPath projects
Automation Ops Series: Session 2 - Governance for UiPath projectsAutomation Ops Series: Session 2 - Governance for UiPath projects
Automation Ops Series: Session 2 - Governance for UiPath projectsDianaGray10
 
20140402 - Smart house demo kit
20140402 - Smart house demo kit20140402 - Smart house demo kit
20140402 - Smart house demo kitJamie (Taka) Wang
 
LF Energy Webinar - Unveiling OpenEEMeter 4.0
LF Energy Webinar - Unveiling OpenEEMeter 4.0LF Energy Webinar - Unveiling OpenEEMeter 4.0
LF Energy Webinar - Unveiling OpenEEMeter 4.0DanBrown980551
 
2024.03.12 Cost drivers of cultivated meat production.pdf
2024.03.12 Cost drivers of cultivated meat production.pdf2024.03.12 Cost drivers of cultivated meat production.pdf
2024.03.12 Cost drivers of cultivated meat production.pdfThe Good Food Institute
 
Design and Modeling for MySQL SCALE 21X Pasadena, CA Mar 2024
Design and Modeling for MySQL SCALE 21X Pasadena, CA Mar 2024Design and Modeling for MySQL SCALE 21X Pasadena, CA Mar 2024
Design and Modeling for MySQL SCALE 21X Pasadena, CA Mar 2024Alkin Tezuysal
 
Emil Eifrem at GraphSummit Copenhagen 2024 - The Art of the Possible.pptx
Emil Eifrem at GraphSummit Copenhagen 2024 - The Art of the Possible.pptxEmil Eifrem at GraphSummit Copenhagen 2024 - The Art of the Possible.pptx
Emil Eifrem at GraphSummit Copenhagen 2024 - The Art of the Possible.pptxNeo4j
 
How to release an Open Source Dataweave Library
How to release an Open Source Dataweave LibraryHow to release an Open Source Dataweave Library
How to release an Open Source Dataweave Libraryshyamraj55
 
Extra-120324-Visite-Entreprise-icare.pdf
Extra-120324-Visite-Entreprise-icare.pdfExtra-120324-Visite-Entreprise-icare.pdf
Extra-120324-Visite-Entreprise-icare.pdfInfopole1
 
The Importance of Indoor Air Quality (English)
The Importance of Indoor Air Quality (English)The Importance of Indoor Air Quality (English)
The Importance of Indoor Air Quality (English)IES VE
 
Stobox 4: Revolutionizing Investment in Real-World Assets Through Tokenization
Stobox 4: Revolutionizing Investment in Real-World Assets Through TokenizationStobox 4: Revolutionizing Investment in Real-World Assets Through Tokenization
Stobox 4: Revolutionizing Investment in Real-World Assets Through TokenizationStobox
 
Explore the UiPath Community and ways you can benefit on your journey to auto...
Explore the UiPath Community and ways you can benefit on your journey to auto...Explore the UiPath Community and ways you can benefit on your journey to auto...
Explore the UiPath Community and ways you can benefit on your journey to auto...DianaGray10
 
Introduction - IPLOOK NETWORKS CO., LTD.
Introduction - IPLOOK NETWORKS CO., LTD.Introduction - IPLOOK NETWORKS CO., LTD.
Introduction - IPLOOK NETWORKS CO., LTD.IPLOOK Networks
 
3 Pitfalls Everyone Should Avoid with Cloud Data
3 Pitfalls Everyone Should Avoid with Cloud Data3 Pitfalls Everyone Should Avoid with Cloud Data
3 Pitfalls Everyone Should Avoid with Cloud DataEric D. Schabell
 
.NET 8 ChatBot with Azure OpenAI Services.pptx
.NET 8 ChatBot with Azure OpenAI Services.pptx.NET 8 ChatBot with Azure OpenAI Services.pptx
.NET 8 ChatBot with Azure OpenAI Services.pptxHansamali Gamage
 
Where developers are challenged, what developers want and where DevEx is going
Where developers are challenged, what developers want and where DevEx is goingWhere developers are challenged, what developers want and where DevEx is going
Where developers are challenged, what developers want and where DevEx is goingFrancesco Corti
 
Graphene Quantum Dots-Based Composites for Biomedical Applications
Graphene Quantum Dots-Based Composites for  Biomedical ApplicationsGraphene Quantum Dots-Based Composites for  Biomedical Applications
Graphene Quantum Dots-Based Composites for Biomedical Applicationsnooralam814309
 
How to become a GDSC Lead GDSC MI AOE.pptx
How to become a GDSC Lead GDSC MI AOE.pptxHow to become a GDSC Lead GDSC MI AOE.pptx
How to become a GDSC Lead GDSC MI AOE.pptxKaustubhBhavsar6
 

Recently uploaded (20)

Planetek Italia Srl - Corporate Profile Brochure
Planetek Italia Srl - Corporate Profile BrochurePlanetek Italia Srl - Corporate Profile Brochure
Planetek Italia Srl - Corporate Profile Brochure
 
Novo Nordisk's journey in developing an open-source application on Neo4j
Novo Nordisk's journey in developing an open-source application on Neo4jNovo Nordisk's journey in developing an open-source application on Neo4j
Novo Nordisk's journey in developing an open-source application on Neo4j
 
My key hands-on projects in Quantum, and QAI
My key hands-on projects in Quantum, and QAIMy key hands-on projects in Quantum, and QAI
My key hands-on projects in Quantum, and QAI
 
Automation Ops Series: Session 2 - Governance for UiPath projects
Automation Ops Series: Session 2 - Governance for UiPath projectsAutomation Ops Series: Session 2 - Governance for UiPath projects
Automation Ops Series: Session 2 - Governance for UiPath projects
 
20140402 - Smart house demo kit
20140402 - Smart house demo kit20140402 - Smart house demo kit
20140402 - Smart house demo kit
 
LF Energy Webinar - Unveiling OpenEEMeter 4.0
LF Energy Webinar - Unveiling OpenEEMeter 4.0LF Energy Webinar - Unveiling OpenEEMeter 4.0
LF Energy Webinar - Unveiling OpenEEMeter 4.0
 
2024.03.12 Cost drivers of cultivated meat production.pdf
2024.03.12 Cost drivers of cultivated meat production.pdf2024.03.12 Cost drivers of cultivated meat production.pdf
2024.03.12 Cost drivers of cultivated meat production.pdf
 
Design and Modeling for MySQL SCALE 21X Pasadena, CA Mar 2024
Design and Modeling for MySQL SCALE 21X Pasadena, CA Mar 2024Design and Modeling for MySQL SCALE 21X Pasadena, CA Mar 2024
Design and Modeling for MySQL SCALE 21X Pasadena, CA Mar 2024
 
Emil Eifrem at GraphSummit Copenhagen 2024 - The Art of the Possible.pptx
Emil Eifrem at GraphSummit Copenhagen 2024 - The Art of the Possible.pptxEmil Eifrem at GraphSummit Copenhagen 2024 - The Art of the Possible.pptx
Emil Eifrem at GraphSummit Copenhagen 2024 - The Art of the Possible.pptx
 
How to release an Open Source Dataweave Library
How to release an Open Source Dataweave LibraryHow to release an Open Source Dataweave Library
How to release an Open Source Dataweave Library
 
Extra-120324-Visite-Entreprise-icare.pdf
Extra-120324-Visite-Entreprise-icare.pdfExtra-120324-Visite-Entreprise-icare.pdf
Extra-120324-Visite-Entreprise-icare.pdf
 
The Importance of Indoor Air Quality (English)
The Importance of Indoor Air Quality (English)The Importance of Indoor Air Quality (English)
The Importance of Indoor Air Quality (English)
 
Stobox 4: Revolutionizing Investment in Real-World Assets Through Tokenization
Stobox 4: Revolutionizing Investment in Real-World Assets Through TokenizationStobox 4: Revolutionizing Investment in Real-World Assets Through Tokenization
Stobox 4: Revolutionizing Investment in Real-World Assets Through Tokenization
 
Explore the UiPath Community and ways you can benefit on your journey to auto...
Explore the UiPath Community and ways you can benefit on your journey to auto...Explore the UiPath Community and ways you can benefit on your journey to auto...
Explore the UiPath Community and ways you can benefit on your journey to auto...
 
Introduction - IPLOOK NETWORKS CO., LTD.
Introduction - IPLOOK NETWORKS CO., LTD.Introduction - IPLOOK NETWORKS CO., LTD.
Introduction - IPLOOK NETWORKS CO., LTD.
 
3 Pitfalls Everyone Should Avoid with Cloud Data
3 Pitfalls Everyone Should Avoid with Cloud Data3 Pitfalls Everyone Should Avoid with Cloud Data
3 Pitfalls Everyone Should Avoid with Cloud Data
 
.NET 8 ChatBot with Azure OpenAI Services.pptx
.NET 8 ChatBot with Azure OpenAI Services.pptx.NET 8 ChatBot with Azure OpenAI Services.pptx
.NET 8 ChatBot with Azure OpenAI Services.pptx
 
Where developers are challenged, what developers want and where DevEx is going
Where developers are challenged, what developers want and where DevEx is goingWhere developers are challenged, what developers want and where DevEx is going
Where developers are challenged, what developers want and where DevEx is going
 
Graphene Quantum Dots-Based Composites for Biomedical Applications
Graphene Quantum Dots-Based Composites for  Biomedical ApplicationsGraphene Quantum Dots-Based Composites for  Biomedical Applications
Graphene Quantum Dots-Based Composites for Biomedical Applications
 
How to become a GDSC Lead GDSC MI AOE.pptx
How to become a GDSC Lead GDSC MI AOE.pptxHow to become a GDSC Lead GDSC MI AOE.pptx
How to become a GDSC Lead GDSC MI AOE.pptx
 

LCU13: Clock bindings

  • 1. Common clock Device Tree bindings Mike Turquette, 2013-10-29
  • 2. connect.linaro.org ● Number of clock driver changes has increased ● Some of the more active platforms are having lots of merge conflicts amongst their own clock driver changes ● I’m happy to take pull requests, instead of cobbling it all together ○ After requisite patch review ● Also might be good to have one owner/maintainer for each platform’s clock driver that marshalls all patches together Quick note on pull requests
  • 3. connect.linaro.org ● The primary benefit that DT brings to clocks is linking clock phandles to consumer devices ● This has been integrated with clk_get ● If DT does absolutely nothing else for clocks, that’s OK by me Device Tree as clkdev
  • 4. connect.linaro.org A “clock controller” node in DT has various clock inputs and various clock outputs. #clock-cells is 1. Use a phandle + index to get a clock. ● Documentation/devicetree/bindings/clock/exynos5250-clock.txt ● arch/arm/boot/dts/exynos5250.dtsi A “per-clock” node corresponds to a single clock entity, often with verbose clock data. #clock-cells is 0. Use just the phandle to get it. ● http://www.spinics.net/lists/arm-kernel/msg282479.html Terminology
  • 5. connect.linaro.org Two approaches - each at opposite ends of the spectrum ● Model a clock controller as a node in DTS ○ Least controversial ○ Little to no hardware description, no per-clock data in DTS ○ Clocks are enumerated in the binding definition ○ Only purpose is to link clock phandles to clock consumer nodes ○ Sometimes referred to as the “clock mapping” approach ○ Results in lots of struct clk object DT clock bindings
  • 6. connect.linaro.org ● Model per-clock data in DTS ○ Most controversial ○ There should be no clock data in the kernel source at all ○ Benefit is moving data out of the kernel - makes Linus happy? ○ Only used in some rare cases - fixed-rate clock, OMAP ○ Results in a single struct clk object DT clock bindings, cont’d
  • 7. connect.linaro.org ● Off-SoC clocks such as oscillators ○ Things that change on a per-board basis ● Intermediate solution for new platforms ○ If bootloader enables clocks then it is possible to use fixed-rate clocks defined in DTS as placeholder clocks ○ This is helpful for drivers that expect to get clocks and know their rate ■ Analogous to a dummy regulator ○ Eventually replace this data in DTS with the appropriate clock controller node binding Why model clock data in DTS?
  • 8. connect.linaro.org ● The only reason is to move 100% of clock data out of the kernel source ○ Flamebait: Is that what Linus wants in The Future? ● If we cannot remove 100% of the static clock data from the kernel then do not bother putting any of it in DTS ○ Just use a clock controller mapping scheme Why model clock data in DTS?
  • 9. connect.linaro.org ● Easy enough for off-chip fixed-rate crystals and oscillators ● What about complex on-SoC clocks? ○ We need to model register-level data such as bitmasks ○ In some cases, create one node per clock Modeling clock data in DTS
  • 10. connect.linaro.org ● Please use the clock-names property to list the input name for the clock with respect to the consuming node ● Not the name of the clock output name from the data sheet! Misc. note on clock-names
  • 11. More about Linaro: http://www.linaro.org/about/ More about Linaro engineering: http://www.linaro.org/engineering/ How to join: http://www.linaro.org/about/how-to-join Linaro members: www.linaro.org/members connect.linaro.org