| Message ID | 20220207234212.685316-1-sean.anderson@seco.com |
|---|---|
| Headers | show |
| Series | Add support for NVMEM API | expand |
Hi Sean, > Should this be implemented on top of/as part of syscon/regmap? In Linux, > all nvmem devices must also implement regmap support, making nvmem a > subset of regmap drivers. There are certainly similarities, but I don't > know if we want to make this depend on regmap. What do you mean by that? I assume with "nvmem devices" you mean the nvmem providers. I've implemented the nvmem provider for MTD OTP devices in linux and there is no regmap support. -michael
Hi Michael, On 2/8/22 10:00 AM, Michael Walle wrote: > Hi Sean, > >> Should this be implemented on top of/as part of syscon/regmap? In Linux, >> all nvmem devices must also implement regmap support, making nvmem a >> subset of regmap drivers. There are certainly similarities, but I don't >> know if we want to make this depend on regmap. > > What do you mean by that? I assume with "nvmem devices" you mean the > nvmem providers. I've implemented the nvmem provider for MTD OTP devices > in linux and there is no regmap support. According to [1], > [The NVMEM] framework is based on regmap, so that most of the > abstraction available in regmap can be reused, across multiple types > of buses. and > 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(). which seems to imply that NVMEM devices should also be regmaps. --Sean [1] https://www.kernel.org/doc/html/latest/driver-api/nvmem.html
Hi Sean, Am 2022-02-08 17:02, schrieb Sean Anderson: >>> Should this be implemented on top of/as part of syscon/regmap? In >>> Linux, >>> all nvmem devices must also implement regmap support, making nvmem a >>> subset of regmap drivers. There are certainly similarities, but I >>> don't >>> know if we want to make this depend on regmap. >> >> What do you mean by that? I assume with "nvmem devices" you mean the >> nvmem providers. I've implemented the nvmem provider for MTD OTP >> devices >> in linux and there is no regmap support. > > According to [1], > >> [The NVMEM] framework is based on regmap, so that most of the >> abstraction available in regmap can be reused, across multiple types >> of buses. > > and > >> 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(). > > which seems to imply that NVMEM devices should also be regmaps. Ahh I see. That seems to be outdated, see commit 795ddd18d38f9762fbfefceab9aa16caef0cf431 ("nvmem: core: remove regmap dependency"). -michael
This adds support for the nvmem-cells properties cropping up in manyb device trees. This is an easy way to load configuration, version information, or calibration data from a non-volatile memory source. For more information, refer to patch 6 ("misc: Add support for nvmem cells"). Should this be implemented on top of/as part of syscon/regmap? In Linux, all nvmem devices must also implement regmap support, making nvmem a subset of regmap drivers. There are certainly similarities, but I don't know if we want to make this depend on regmap. For the moment I have only added some integration tests using the ethernet addresses. This hits the main code paths (looking up nvmem cells) but doesn't test writing. I can add a few stand-alone tests if desired. The patches are structured in the following manner: 1-5: These are general cleanups, and may be applied independently of the rest of the series. 6-10: Add NVMEM support 11-14: Support reading ethernet addresses using the NVMEM API and add some tests. Sean Anderson (14): sandbox: net: Remove fake-host-hwaddr sandbox: Remove eth2addr from environment test: eth: Add test for ethernet addresses sandbox: Move some mac addresses to device tree misc: i2c_eeprom: Make i2c_eeprom_write use a const buf misc: Add support for nvmem cells sandbox: Enable NVMEM rtc: Implement nvmem interface misc: i2c_eeprom: Implement nvmem interface misc: Implement nvmem interface net: Add support for reading mac addresses from nvmem cells test: Load mac address with i2c eeprom test: Load mac address using RTC test: Load mac address using misc device MAINTAINERS | 7 ++ arch/sandbox/dts/sandbox.dts | 1 - arch/sandbox/dts/sandbox64.dts | 1 - arch/sandbox/dts/test.dts | 29 ++++- board/sandbox/sandbox.env | 4 - configs/sandbox64_defconfig | 1 + configs/sandbox_defconfig | 1 + configs/sandbox_flattree_defconfig | 1 + configs/sandbox_noinst_defconfig | 1 + configs/sandbox_spl_defconfig | 1 + doc/api/index.rst | 1 + doc/api/nvmem.rst | 7 ++ drivers/misc/Kconfig | 16 +++ drivers/misc/Makefile | 1 + drivers/misc/i2c_eeprom.c | 22 +++- drivers/misc/i2c_eeprom_emul.c | 4 + drivers/misc/misc-uclass.c | 31 +++++ drivers/misc/misc_sandbox.c | 3 + drivers/misc/nvmem.c | 109 +++++++++++++++++ drivers/net/sandbox.c | 10 +- drivers/rtc/i2c_rtc_emul.c | 10 ++ drivers/rtc/rtc-uclass.c | 19 +++ include/i2c_eeprom.h | 3 +- include/nvmem.h | 185 +++++++++++++++++++++++++++++ net/eth-uclass.c | 13 +- test/dm/eth.c | 28 +++++ 26 files changed, 484 insertions(+), 25 deletions(-) create mode 100644 doc/api/nvmem.rst create mode 100644 drivers/misc/nvmem.c create mode 100644 include/nvmem.h