Hi Rob, > Stefan Wahren <stefan.wahren@xxxxxxxx> hat am 7. Dezember 2018 um 09:10 geschrieben: > > > Hi Rob, > > Am 07.12.18 um 00:49 schrieb Rob Herring: > > On Wed, Nov 21, 2018 at 02:11:40PM +0100, Stefan Wahren wrote: > >> This patch adds the devicetree binding for Raspberry Pi customer OTP > >> driver. > >> > >> Signed-off-by: Stefan Wahren <stefan.wahren@xxxxxxxx> > >> --- > >> .../nvmem/raspberrypi,bcm2835-customer-otp.txt | 22 ++++++++++++++++++++++ > >> 1 file changed, 22 insertions(+) > >> create mode 100644 Documentation/devicetree/bindings/nvmem/raspberrypi,bcm2835-customer-otp.txt > >> > >> diff --git a/Documentation/devicetree/bindings/nvmem/raspberrypi,bcm2835-customer-otp.txt b/Documentation/devicetree/bindings/nvmem/raspberrypi,bcm2835-customer-otp.txt > >> new file mode 100644 > >> index 0000000..041ff17 > >> --- /dev/null > >> +++ b/Documentation/devicetree/bindings/nvmem/raspberrypi,bcm2835-customer-otp.txt > >> @@ -0,0 +1,22 @@ > >> +Customer OTP Memory for Raspberry Pi > >> + > >> +The VC4 firmware exposes a mailbox interface that allows the ARM core > >> +to access the customer part of the OTP memory. > >> + > >> +The OTP node must be a child node of the Raspberry Pi firmware node. > >> + > >> +Required properties : > >> +- compatible : Should be "raspberrypi,bcm2835-customer-otp" > > Why do we need this child node? Can't the parent instantiate this? > > > > Are there OTP fields you want to expose in DT? > > the customer part of the OTP is reserved (initialized with zero) for > user who wants to use the Raspberry Pi (mostly the Compute Module) in > their custom designs. So i cannot provide any nvmem cells yet because it > is up to the user to define them (e.g. hardware related values like > serial numbers, MAC addresses for additional network interfaces or > calibration values). But yes i consider the binding and the ability to > define nvmem cells via devicetree as a great feature. > > Currently the Foundation suggests to use the mailbox interface from > userspace [1], but i prefer a more common way like nvmem. > > [1] - > https://www.raspberrypi.org/documentation/hardware/industrial/README.md > did it answer your questions? Stefan
