diff options
author | Srinivas Kandagatla <srinivas.kandagatla@linaro.org> | 2015-09-01 11:54:38 +0100 |
---|---|---|
committer | Srinivas Kandagatla <srinivas.kandagatla@linaro.org> | 2015-09-01 11:54:38 +0100 |
commit | 9f12ae3a01270cbe7fbc875c528b0d5288ea8eea (patch) | |
tree | a1bc45c219a51a466f6573ba16162e9bbe4f71d4 /Documentation | |
parent | 7886f277c418bd5d76b697cd2219fd7fcb234405 (diff) | |
parent | 03bbac4c8c19ec8b4758916baa6ed57c5f720808 (diff) |
Merge branch 'tracking-qcomlt-nvmem' into integration-linux-qcomlt
* tracking-qcomlt-nvmem:
nvmem: Add to MAINTAINERS for nvmem framework
nvmem: sunxi: Move the SID driver to the nvmem framework
nvmem: qfprom: Add bindings for qfprom
nvmem: qfprom: Add Qualcomm QFPROM support.
Documentation: nvmem: add nvmem api level and how-to doc
nvmem: Add bindings for simple nvmem framework
nvmem: Add nvmem_device based consumer apis.
nvmem: Add a simple NVMEM framework for consumers
nvmem: Add a simple NVMEM framework for nvmem providers
Diffstat (limited to 'Documentation')
-rw-r--r-- | Documentation/ABI/testing/sysfs-driver-sunxi-sid | 22 | ||||
-rw-r--r-- | Documentation/devicetree/bindings/nvmem/allwinner,sunxi-sid.txt (renamed from Documentation/devicetree/bindings/misc/allwinner,sunxi-sid.txt) | 4 | ||||
-rw-r--r-- | Documentation/devicetree/bindings/nvmem/nvmem.txt | 80 | ||||
-rw-r--r-- | Documentation/devicetree/bindings/nvmem/qfprom.txt | 35 | ||||
-rw-r--r-- | Documentation/nvmem/nvmem.txt | 152 |
5 files changed, 271 insertions, 22 deletions
diff --git a/Documentation/ABI/testing/sysfs-driver-sunxi-sid b/Documentation/ABI/testing/sysfs-driver-sunxi-sid deleted file mode 100644 index ffb9536f6ecc..000000000000 --- a/Documentation/ABI/testing/sysfs-driver-sunxi-sid +++ /dev/null @@ -1,22 +0,0 @@ -What: /sys/devices/*/<our-device>/eeprom -Date: August 2013 -Contact: Oliver Schinagl <oliver@schinagl.nl> -Description: read-only access to the SID (Security-ID) on current - A-series SoC's from Allwinner. Currently supports A10, A10s, A13 - and A20 CPU's. The earlier A1x series of SoCs exports 16 bytes, - whereas the newer A20 SoC exposes 512 bytes split into sections. - Besides the 16 bytes of SID, there's also an SJTAG area, - HDMI-HDCP key and some custom keys. Below a quick overview, for - details see the user manual: - 0x000 128 bit root-key (sun[457]i) - 0x010 128 bit boot-key (sun7i) - 0x020 64 bit security-jtag-key (sun7i) - 0x028 16 bit key configuration (sun7i) - 0x02b 16 bit custom-vendor-key (sun7i) - 0x02c 320 bit low general key (sun7i) - 0x040 32 bit read-control access (sun7i) - 0x064 224 bit low general key (sun7i) - 0x080 2304 bit HDCP-key (sun7i) - 0x1a0 768 bit high general key (sun7i) -Users: any user space application which wants to read the SID on - Allwinner's A-series of CPU's. diff --git a/Documentation/devicetree/bindings/misc/allwinner,sunxi-sid.txt b/Documentation/devicetree/bindings/nvmem/allwinner,sunxi-sid.txt index fabdf64a5737..d543ed3f5363 100644 --- a/Documentation/devicetree/bindings/misc/allwinner,sunxi-sid.txt +++ b/Documentation/devicetree/bindings/nvmem/allwinner,sunxi-sid.txt @@ -4,6 +4,10 @@ Required properties: - compatible: "allwinner,sun4i-a10-sid" or "allwinner,sun7i-a20-sid" - reg: Should contain registers location and length += Data cells = +Are child nodes of qfprom, bindings of which as described in +bindings/nvmem/nvmem.txt + Example for sun4i: sid@01c23800 { compatible = "allwinner,sun4i-a10-sid"; diff --git a/Documentation/devicetree/bindings/nvmem/nvmem.txt b/Documentation/devicetree/bindings/nvmem/nvmem.txt new file mode 100644 index 000000000000..b52bc11e9597 --- /dev/null +++ b/Documentation/devicetree/bindings/nvmem/nvmem.txt @@ -0,0 +1,80 @@ += NVMEM(Non Volatile Memory) Data Device Tree Bindings = + +This binding is intended to represent the location of hardware +configuration data stored in NVMEMs like eeprom, efuses and so on. + +On a significant proportion of boards, the manufacturer has stored +some data on NVMEM, for the OS to be able to retrieve these information +and act upon it. Obviously, the OS has to know about where to retrieve +these data from, and where they are stored on the storage device. + +This document is here to document this. + += Data providers = +Contains bindings specific to provider drivers and data cells as children +of this node. + +Optional properties: + read-only: Mark the provider as read only. + += Data cells = +These are the child nodes of the provider which contain data cell +information like offset and size in nvmem provider. + +Required properties: +reg: specifies the offset in byte within the storage device. + +Optional properties: + +bits: Is pair of bit location and number of bits, which specifies offset + in bit and number of bits within the address range specified by reg property. + Offset takes values from 0-7. + +For example: + + /* Provider */ + qfprom: qfprom@00700000 { + ... + + /* Data cells */ + tsens_calibration: calib@404 { + reg = <0x404 0x10>; + }; + + tsens_calibration_bckp: calib_bckp@504 { + reg = <0x504 0x11>; + bits = <6 128> + }; + + pvs_version: pvs-version@6 { + reg = <0x6 0x2> + bits = <7 2> + }; + + speed_bin: speed-bin@c{ + reg = <0xc 0x1>; + bits = <2 3>; + + }; + ... + }; + += Data consumers = +Are device nodes which consume nvmem data cells/providers. + +Required-properties: +nvmem-cells: list of phandle to the nvmem data cells. +nvmem-cell-names: names for the each nvmem-cells specified. Required if + nvmem-cells is used. + +Optional-properties: +nvmem : list of phandles to nvmem providers. +nvmem-names: names for the each nvmem provider. required if nvmem is used. + +For example: + + tsens { + ... + nvmem-cells = <&tsens_calibration>; + nvmem-cell-names = "calibration"; + }; diff --git a/Documentation/devicetree/bindings/nvmem/qfprom.txt b/Documentation/devicetree/bindings/nvmem/qfprom.txt new file mode 100644 index 000000000000..4ad68b7f5c18 --- /dev/null +++ b/Documentation/devicetree/bindings/nvmem/qfprom.txt @@ -0,0 +1,35 @@ += Qualcomm QFPROM device tree bindings = + +This binding is intended to represent QFPROM which is found in most QCOM SOCs. + +Required properties: +- compatible: should be "qcom,qfprom" +- reg: Should contain registers location and length + += Data cells = +Are child nodes of qfprom, bindings of which as described in +bindings/nvmem/nvmem.txt + +Example: + + qfprom: qfprom@00700000 { + compatible = "qcom,qfprom"; + reg = <0x00700000 0x8000>; + ... + /* Data cells */ + tsens_calibration: calib@404 { + reg = <0x4404 0x10>; + }; + }; + + += Data consumers = +Are device nodes which consume nvmem data cells. + +For example: + + tsens { + ... + nvmem-cells = <&tsens_calibration>; + nvmem-cell-names = "calibration"; + }; diff --git a/Documentation/nvmem/nvmem.txt b/Documentation/nvmem/nvmem.txt new file mode 100644 index 000000000000..dbd40d879239 --- /dev/null +++ b/Documentation/nvmem/nvmem.txt @@ -0,0 +1,152 @@ + NVMEM SUBSYSTEM + Srinivas Kandagatla <srinivas.kandagatla@linaro.org> + +This document explains the NVMEM Framework along with the APIs provided, +and how to use it. + +1. Introduction +=============== +*NVMEM* is the abbreviation for Non Volatile Memory layer. It is used to +retrieve configuration of SOC or Device specific data from non volatile +memories like eeprom, efuses and so on. + +Before this framework existed, NVMEM drivers like eeprom were stored in +drivers/misc, where they all had to duplicate pretty much the same code to +register a sysfs file, allow in-kernel users to access the content of the +devices they were driving, etc. + +This was also a problem as far as other in-kernel users were involved, since +the solutions used were pretty much different from one driver to another, there +was a rather big abstraction leak. + +This framework aims at solve these problems. It also introduces DT +representation for consumer devices to go get the data they require (MAC +Addresses, SoC/Revision ID, part numbers, and so on) from the NVMEMs. This +framework is based on regmap, so that most of the abstraction available in +regmap can be reused, across multiple types of buses. + +NVMEM Providers ++++++++++++++++ + +NVMEM provider refers to an entity that implements methods to initialize, read +and write the non-volatile memory. + +2. Registering/Unregistering the NVMEM provider +=============================================== + +A NVMEM provider can register with NVMEM core by supplying relevant +nvmem configuration to nvmem_register(), on success core would return a valid +nvmem_device pointer. + +nvmem_unregister(nvmem) is used to unregister a previously registered provider. + +For example, a simple qfprom case: + +static struct nvmem_config econfig = { + .name = "qfprom", + .owner = THIS_MODULE, +}; + +static int qfprom_probe(struct platform_device *pdev) +{ + ... + econfig.dev = &pdev->dev; + nvmem = nvmem_register(&econfig); + ... +} + +It is mandatory that the NVMEM provider has a regmap associated with its +struct device. Failure to do would return error code from nvmem_register(). + +NVMEM Consumers ++++++++++++++++ + +NVMEM consumers are the entities which make use of the NVMEM provider to +read from and to NVMEM. + +3. NVMEM cell based consumer APIs +================================= + +NVMEM cells are the data entries/fields in the NVMEM. +The NVMEM framework provides 3 APIs to read/write NVMEM cells. + +struct nvmem_cell *nvmem_cell_get(struct device *dev, const char *name); +struct nvmem_cell *devm_nvmem_cell_get(struct device *dev, const char *name); + +void nvmem_cell_put(struct nvmem_cell *cell); +void devm_nvmem_cell_put(struct device *dev, struct nvmem_cell *cell); + +void *nvmem_cell_read(struct nvmem_cell *cell, ssize_t *len); +int nvmem_cell_write(struct nvmem_cell *cell, void *buf, ssize_t len); + +*nvmem_cell_get() apis will get a reference to nvmem cell for a given id, +and nvmem_cell_read/write() can then read or write to the cell. +Once the usage of the cell is finished the consumer should call *nvmem_cell_put() +to free all the allocation memory for the cell. + +4. Direct NVMEM device based consumer APIs +========================================== + +In some instances it is necessary to directly read/write the NVMEM. +To facilitate such consumers NVMEM framework provides below apis. + +struct nvmem_device *nvmem_device_get(struct device *dev, const char *name); +struct nvmem_device *devm_nvmem_device_get(struct device *dev, + const char *name); +void nvmem_device_put(struct nvmem_device *nvmem); +int nvmem_device_read(struct nvmem_device *nvmem, unsigned int offset, + size_t bytes, void *buf); +int nvmem_device_write(struct nvmem_device *nvmem, unsigned int offset, + size_t bytes, void *buf); +int nvmem_device_cell_read(struct nvmem_device *nvmem, + struct nvmem_cell_info *info, void *buf); +int nvmem_device_cell_write(struct nvmem_device *nvmem, + struct nvmem_cell_info *info, void *buf); + +Before the consumers can read/write NVMEM directly, it should get hold +of nvmem_controller from one of the *nvmem_device_get() api. + +The difference between these apis and cell based apis is that these apis always +take nvmem_device as parameter. + +5. Releasing a reference to the NVMEM +===================================== + +When a consumers no longer needs the NVMEM, it has to release the reference +to the NVMEM it has obtained using the APIs mentioned in the above section. +The NVMEM framework provides 2 APIs to release a reference to the NVMEM. + +void nvmem_cell_put(struct nvmem_cell *cell); +void devm_nvmem_cell_put(struct device *dev, struct nvmem_cell *cell); +void nvmem_device_put(struct nvmem_device *nvmem); +void devm_nvmem_device_put(struct device *dev, struct nvmem_device *nvmem); + +Both these APIs are used to release a reference to the NVMEM and +devm_nvmem_cell_put and devm_nvmem_device_put destroys the devres associated +with this NVMEM. + +Userspace ++++++++++ + +6. Userspace binary interface +============================== + +Userspace can read/write the raw NVMEM file located at +/sys/bus/nvmem/devices/*/nvmem + +ex: + +hexdump /sys/bus/nvmem/devices/qfprom0/nvmem + +0000000 0000 0000 0000 0000 0000 0000 0000 0000 +* +00000a0 db10 2240 0000 e000 0c00 0c00 0000 0c00 +0000000 0000 0000 0000 0000 0000 0000 0000 0000 +... +* +0001000 + +7. DeviceTree Binding +===================== + +See Documentation/devicetree/bindings/nvmem/nvmem.txt |