Add a simple description of struct nvmem_config and its fields.

Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc: Heiko Stuebner <heiko@sntech.de>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Carlo Caione <carlo@caione.org>
Cc: Kevin Hilman <khilman@baylibre.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: cphealy@gmail.com
Cc: linux-kernel@vger.kernel.org
Cc: linux-mediatek@lists.infradead.org
Cc: linux-rockchip@lists.infradead.org
Cc: linux-amlogic@lists.infradead.org
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: NAndrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: NSrinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The new support for nvmem devices from the rtc layer caused a build
error in some configurations:

include/linux/nvmem-provider.h: In function 'nvmem_register':
include/linux/nvmem-provider.h:51:9: error: implicit declaration of function 'ERR_PTR' [-Werror=implicit-function-declaration]

This adds the missing include to ensure we can always include
the header.

Fixes: 697e5a47 ("rtc: add generic nvmem support")
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NSrinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

nvmem uses regmap_raw_read/write apis to read/write data from providers,
regmap raw apis stopped working with recent kernels which removed raw
accessors on mmio bus. This resulted in broken nvmem for providers
which are based on regmap mmio bus. This issue can be fixed temporarly
by moving to other regmap apis, but we might hit same issue in future.
Moving to interfaces based on read/write callbacks from providers would
be more robust.

This patch removes regmap dependency from nvmem and introduces
read/write callbacks from the providers.

Without this patch nvmem providers like qfprom based on regmap mmio
bus would not work.
Reported-by: NRajendra Nayak <rjendra@qti.qualcomm.com>
Signed-off-by: NSrinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Older drivers made an 'eeprom' file available in the /sys device
directory. Have the NVMEM core provide this to retain backwards
compatibility.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Acked-by: NSrinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Legacy AT24, AT25 EEPROMs are exported in sys so that only root can
read the contents. The EEPROMs may contain sensitive information. Add
a flag so the provide can indicate that NVMEM should also restrict
access to root only.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Acked-by: NSrinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch adds just providers part of the framework just to enable easy
review.

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

This 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.

Having regmap interface to this framework would give much better
abstraction for nvmems on different buses.
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>
[Maxime Ripard: intial version of eeprom framework]
Signed-off-by: NSrinivas Kandagatla <srinivas.kandagatla@linaro.org>
Tested-by: NStefan Wahren <stefan.wahren@i2se.com>
Tested-by: NPhilipp Zabel <p.zabel@pengutronix.de>
Tested-by: NRajendra Nayak <rnayak@codeaurora.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>