[PATCH v5 00/11] Add simple NVMEM Framework via regmap.

Srinivas Kandagatla
2015-05-21T16:42:15Z

Thankyou all for providing inputs and comments on previous versions of this patchset.
Here is the v5 of the patchset addressing all the issues raised as
part of previous versions review.

This patchset adds a new simple NVMEM framework to kernel.

Up until now, NVMEM drivers 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 on driver to another, there
was a rather big abstraction leak.

Introduction of this framework aims at solving this. 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.

After learning few things about QCOM qfprom and other eeprom/efuses, which
has packed fields at bit level. Which makes it important to add support to
such memories. This version adds support to this type of non volatile
memories by adding support to bit level nvmem-cells.

Having regmap interface to this framework would give much better
abstraction for nvmems on different buses.

patch 1-2 Introduces two regmap helper functions.
patch 3-6 Introduces the NVMEM framework.
Patch 7 Adds helper functions for nvmems based on mmio.
Patch 8 migrates an existing driver to nvmem framework.
Patch 9-10 Adds Qualcomm specific qfprom driver.
Patch 11 adds entry in MAINTAINERS.

Its also possible to migrate other nvmem drivers to this framework.

Providers APIs:
nvmem_register/unregister();

Consumers APIs:
Cell based apis for both DT/Non-DT:
nvmem_cell_get()/nvmem_cell_put();
nvmem_cell_read()/nvmem_cell_write();

Raw byte access apis for both DT/non-DT.
nvmem_device_get()/nvmem_device_put()
nvmem_device_read()/nvmem_device_write();
nvmem_device_cell_read()/nvmem_device_cell_write();

Device Tree:

/* Provider */
qfprom: qfprom at 00700000 {
...

/* Data cells */
tsens_calibration: calib at 404 {
reg = <0x404 0x10>;
};

tsens_calibration_bckp: calib_bckp at 504 {
reg = <0x504 0x11>;
bit-offset = 6;
nbits = 128;
};

pvs_version: pvs-version at 6 {
reg = <0x6 0x2>
bit-offset = 7;
nbits = 2;
};

speed_bin: speed-bin at c{
reg = <0xc 0x1>;
bit-offset = 2;
nbits = 3;

};
...
};

userspace interface: binary file in /sys/class/nvmem/*/nvmem

ex:
hexdump /sys/class/nvmem/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

Changes since v4(https://lkml.org/lkml/2015/3/30/725)
* rename eeprom to nvmem suggested by Matt Porter
* added bit level support to nvmem cells, if not framework is
not usable for qcom platforms.
* removed ternary operator shortcut suggested by Mark B.
* unified consumer/provider apis for both DT and non-DT.
* added name support for cell.
* added bit level bindings.
* added read-only support suggested by Matt Porter and others.
* added new nvmem_device based consumer apis.

Changes since v3(https://lkml.org/lkml/2015/3/24/1066)
* simplified logic in bin_attr_eeprom_read/write spotted by Mark Brown.
* moved from using regmap_bulk_read/write to regmap_raw_read/write
spotted by Mark Brown
* Fixed return error codes for the dummy wrappers spotted by Sascha Hauer
* Fixed various error code checks in core spotted by Sascha Hauer.
* Simplified consumer bindings suggested by Sascha Hauer.
* Added eeprom-mmio helper functions.

Changes since v2(https://lkml.org/lkml/2015/3/13/168)
* Fixed error handling in eeprom_register spotted by Mark Brown
* Added new regmap_get_max_register() and regmap_get_reg_stride().
* Fixed module build errors reported by kbuild robot.
* recycle the ids when eeprom provider is released.

Changes since v1(https://lkml.org/lkml/2015/3/5/153)
* Fix various Licencing issues spotted by Paul Bolle and Mark Brown
* Allow eeprom core to build as module spotted by Paul Bolle.
* Fix various kconfig issues spotted by Paul Bolle.
* remove unessary atomic varible spotted by Mark Brown.
* Few cleanups and common up some of the code in core.
* Add qfprom bindings.

Changes since RFC(https://lkml.org/lkml/2015/2/19/307)
* Fix documentation and error checks in read/write spotted by Andrew Lunn
* Kconfig fix suggested by Stephen Boyd.
* Add module owner suggested by Stephen Boyd and others.
* Fix unsafe handling of eeprom in unregister spotted by Russell and Mark Brown.
* seperate bindings patch as suggested by Rob.
* Add MAINTAINERS as suggested by Rob.
* Added support to allow reading eeprom for things like serial number which
* canbe scatters across.
* Added eeprom data using reg property suggested by Sascha and Stephen.
* Added non-DT support.
* Move kerneldoc to the src files spotted by Mark Brown.
* Remove local list and do eeprom lookup by using class_find_device()

Thanks,
srini

Maxime Ripard (1):
nvmem: sunxi: Move the SID driver to the nvmem framework

Srinivas Kandagatla (10):
regmap: Introduce regmap_get_max_register.
regmap: Introduce regmap_get_reg_stride.
nvmem: Add a simple NVMEM framework for nvmem providers
nvmem: Add a simple NVMEM framework for consumers
nvmem: Add nvmem_device based consumer apis.
nvmem: Add bindings for simple nvmem framework
nvmem: Add simple nvmem-mmio consumer helper functions.
nvmem: qfprom: Add Qualcomm QFPROM support.
nvmem: qfprom: Add bindings for qfprom
nvmem: Add to MAINTAINERS for nvmem framework

Documentation/ABI/testing/sysfs-driver-sunxi-sid | 22 -
.../bindings/misc/allwinner,sunxi-sid.txt | 17 -
.../bindings/nvmem/allwinner,sunxi-sid.txt | 21 +
Documentation/devicetree/bindings/nvmem/nvmem.txt | 84 ++
Documentation/devicetree/bindings/nvmem/qfprom.txt | 35 +
MAINTAINERS | 9 +
drivers/Kconfig | 2 +
drivers/Makefile | 1 +
drivers/base/regmap/regmap.c | 24 +
drivers/misc/eeprom/Kconfig | 13 -
drivers/misc/eeprom/Makefile | 1 -
drivers/misc/eeprom/sunxi_sid.c | 156 ----
drivers/nvmem/Kconfig | 36 +
drivers/nvmem/Makefile | 13 +
drivers/nvmem/core.c | 864 +++++++++++++++++++++
drivers/nvmem/nvmem-mmio.c | 69 ++
drivers/nvmem/nvmem-mmio.h | 41 +
drivers/nvmem/qfprom.c | 51 ++
drivers/nvmem/sunxi-sid.c | 64 ++
include/linux/nvmem-consumer.h | 106 +++
include/linux/nvmem-provider.h | 47 ++
include/linux/regmap.h | 14 +
22 files changed, 1481 insertions(+), 209 deletions(-)
delete mode 100644 Documentation/ABI/testing/sysfs-driver-sunxi-sid
delete mode 100644 Documentation/devicetree/bindings/misc/allwinner,sunxi-sid.txt
create mode 100644 Documentation/devicetree/bindings/nvmem/allwinner,sunxi-sid.txt
create mode 100644 Documentation/devicetree/bindings/nvmem/nvmem.txt
create mode 100644 Documentation/devicetree/bindings/nvmem/qfprom.txt
delete mode 100644 drivers/misc/eeprom/sunxi_sid.c
create mode 100644 drivers/nvmem/Kconfig
create mode 100644 drivers/nvmem/Makefile
create mode 100644 drivers/nvmem/core.c
create mode 100644 drivers/nvmem/nvmem-mmio.c
create mode 100644 drivers/nvmem/nvmem-mmio.h
create mode 100644 drivers/nvmem/qfprom.c
create mode 100644 drivers/nvmem/sunxi-sid.c
create mode 100644 include/linux/nvmem-consumer.h
create mode 100644 include/linux/nvmem-provider.h

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1.9.1