[PATCH RFC V3 2/3] mxs: add driver for ocotp in i.MX23 and i.MX28
Stefan Wahren
stefan.wahren at i2se.com
Wed Oct 29 00:14:24 PDT 2014
Hi Ezequiel,
Am 28.10.2014 um 18:17 schrieb Ezequiel Garcia:
> On 10/20/2014 11:44 AM, Arnd Bergmann wrote:
>> On Saturday 18 October 2014 10:32:51 Stefan Wahren wrote:
>>> This patch brings readonly support for the On Chip OTP cells in the i.MX23
>>> and i.MX28 processor. The driver uses files (one for each cell) in sysfs
>>> as interface.
>>>
>>> Signed-off-by: Stefan Wahren <stefan.wahren at i2se.com>
>>> ---
>>> drivers/misc/Kconfig | 13 ++
>>> drivers/misc/Makefile | 1 +
>>> drivers/misc/fsl_ocotp.c | 332 ++++++++++++++++++++++++++++++++++++++++++++++
>>> 3 files changed, 346 insertions(+)
>>> create mode 100644 drivers/misc/fsl_ocotp.c
>>>
>>> diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
>>> index b841180..7455efa 100644
>>> --- a/drivers/misc/Kconfig
>>> +++ b/drivers/misc/Kconfig
>>> @@ -515,6 +515,19 @@ config VEXPRESS_SYSCFG
>>> bus. System Configuration interface is one of the possible means
>>> of generating transactions on this bus.
>>>
>>> +config FSL_OCOTP
>>> + tristate "Freescale MXS On-Chip OTP Memory Support"
>>> + depends on ARCH_MXS && SYSFS
>>> + help
>>> + If you say Y here, you will get support for a readonly
>>> + SysFS interface for the One Time Programmable memory pages that
>>> + are stored on the Freescale i.MX23/i.MX28 processor.
>>> +
>>> + To compile this driver as a module, choose M here: the module
>>> + will be called fsl_ocotp.
>>> +
>>> + If unsure, it is safe to say N.
>>>
>> I think this needs to be an MTD driver, not a "misc" driver, and it
>> should use the proper MTD interfaces instead of introducing an
>> incompatible set of interfaces.
>>
> Are you sure MTD is the right place? Recently an eFuse driver was merged
> in drivers/soc/tegra/fuse:
>
> http://lxr.free-electrons.com/source/drivers/soc/tegra/fuse/fuse-tegra.c
>
> Isn't this a similar device?
the i.MX28 Reference manual speak also of eFuses and this driver looks
more familiar to me.
>From my point of view it's important to keep the structure of 40 OTP
register a 32 bits. It doesn't make sense to merge them all together in
a blob of 1280 bits and a userspace tool needs to separate it again.
Thanks for the hint.
BR Stefan
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