Sometimes the clients of nvmem just want to get a number out of
nvmem. They don't want to think about exactly how many bytes the nvmem
cell took up. They just want the number. Let's make it easy.
In general this concept is useful because nvmem space is precious and
usually the fewest bits are allocated that will hold a given value on
a given system. However, even though small numbers might be fine on
one system that doesn't mean that logically the number couldn't be
bigger. Imagine nvmem containing a max frequency for a component. On
one system perhaps that fits in 16 bits. On another system it might
fit in 32 bits. The code reading this number doesn't care--it just
wants the number.
We'll provide two functions: nvmem_cell_read_variable_le_u32() and
nvmem_cell_read_variable_le_u64().
Comparing these to the existing functions like nvmem_cell_read_u32():
* These new functions have no problems if the value was stored in
nvmem in fewer bytes. It's OK to use these function as long as the
value stored will fit in 32-bits (or 64-bits).
* These functions avoid problems that the earlier APIs had with bit
offsets. For instance, you can't use nvmem_cell_read_u32() to read a
value has nbits=32 and bit_offset=4 because the nvmem cell must be
at least 5 bytes big to hold this value. The new API accounts for
this and works fine.
* These functions make it very explicit that they assume that the
number was stored in little endian format. The old functions made
this assumption whenever bit_offset was non-zero (see
nvmem_shift_read_buffer_in_place()) but didn't whenever the
bit_offset was zero.
NOTE: it's assumed that we don't need an 8-bit or 16-bit version of
this function. The 32-bit version of the function can be used to read
8-bit or 16-bit data.
At the moment, I'm only adding the "unsigned" versions of these
functions, but if it ends up being useful someone could add a "signed"
version that did 2's complement sign extension.
At the moment, I'm only adding the "little endian" versions of these
functions. Adding the "big endian" version would require adding "big
endian" support to nvmem_shift_read_buffer_in_place().
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20210330111241.19401-7-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Complement the u16, u32 and u64 helpers with a u8 variant to ease
accessing byte-sized values.
This helper will be useful for Realtek Digital Home Center platforms,
which store some byte and sub-byte sized values in non-volatile memory.
Signed-off-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20200722100705.7772-7-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add nvmem_cell_read_u64() helper to ease read of an u64 value on consumer
side. This helper is useful on some sunxi platform that has 64 bits data
cells stored in no volatile memory.
Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20200310132257.23358-4-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Here is the big set of char/misc and other driver patches for 5.5-rc1
Loads of different things in here, this feels like the catch-all of
driver subsystems these days. Full details are in the shortlog, but
nothing major overall, just lots of driver updates and additions.
All of these have been in linux-next for a while with no reported
issues.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'char-misc-5.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc
Pull char/misc driver updates from Greg KH:
"Here is the big set of char/misc and other driver patches for 5.5-rc1
Loads of different things in here, this feels like the catch-all of
driver subsystems these days. Full details are in the shortlog, but
nothing major overall, just lots of driver updates and additions.
All of these have been in linux-next for a while with no reported
issues"
* tag 'char-misc-5.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (198 commits)
char: Fix Kconfig indentation, continued
habanalabs: add more protection of device during reset
habanalabs: flush EQ workers in hard reset
habanalabs: make the reset code more consistent
habanalabs: expose reset counters via existing INFO IOCTL
habanalabs: make code more concise
habanalabs: use defines for F/W files
habanalabs: remove prints on successful device initialization
habanalabs: remove unnecessary checks
habanalabs: invalidate MMU cache only once
habanalabs: skip VA block list update in reset flow
habanalabs: optimize MMU unmap
habanalabs: prevent read/write from/to the device during hard reset
habanalabs: split MMU properties to PCI/DRAM
habanalabs: re-factor MMU masks and documentation
habanalabs: type specific MMU cache invalidation
habanalabs: re-factor memory module code
habanalabs: export uapi defines to user-space
habanalabs: don't print error when queues are full
habanalabs: increase max jobs number to 512
...
nvmem_cell_write's buf argument uses different types based on
the configuration of CONFIG_NVMEM. The function prototype for
enabled NVMEM uses 'void *' type, but the static dummy function
for disabled NVMEM uses 'const char *' instead. Fix the different
behaviour by always expecting a 'void *' typed buf argument.
Fixes: 7a78a7f769 ("power: reset: nvmem-reboot-mode: use NVMEM as reboot mode write interface")
Reported-by: kbuild test robot <lkp@intel.com>
Cc: Han Nandor <nandor.han@vaisala.com>
Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Reviewed-By: Han Nandor <nandor.han@vaisala.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20191029114240.14905-2-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
nvmem_device_find provides a way to search for nvmem devices with
the help of a match function simlair to bus_find_device.
Reviewed-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Acked-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: Lee Jones <lee.jones@linaro.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: linux-rtc@vger.kernel.org
Cc: linux-serial@vger.kernel.org
Add nvmem_cell_read_u16() helper to ease read of an u16 value on consumer
side. This is inspired by nvmem_cell_read_u32() function.
This helper is useful on stm32 that has 16 bits data cells stored in non
volatile memory.
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Checkpatch emits warnings when using ENOSYS. Some of the frameworks
started using EOPNOTSUPP as return values for API functions when given
subsystem is disabled in Kconfig.
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The argument representing the cell name in the nvmem_cell_get() family
of functions is not consistend between function prototypes and
definitions. Name it 'id' in all those routines. This is in line with
other frameworks and can represent both the DT cell name from the
nvmem-cell-names property as well as the con_id field from cell
lookup entries.
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add a blocking notifier chain with four events (add and remove for
both devices and cells) so that users can get notified about the
addition of nvmem resources they're waiting for.
We'll use this instead of the at24 setup callback in the mityomapl138
board file.
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add a way for machine code users to associate devices with nvmem cells.
This restores the support for non-DT systems but following a different
approach. Cells must now be associated with devices using provided
routines and data structures before they can be retrieved using
nvmem_cell_get().
It's still possible to define cells statically in nvmem_config but
cells created this way still need to be associated with consumers using
lookup entries.
Note that nvmem_find() must be moved higher in the source file as we
want to call it from __nvmem_device_get() for devices that don't have
a device node.
The signature of __nvmem_device_get() is also changed as it's no longer
used to retrieve cells.
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Kernel users don't have any means of checking the names of nvmem
devices. Add a routine that returns the name of the nvmem provider.
This will be useful for future nvmem notifier subscribers - otherwise
they can't check what device is being added/removed.
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
missing err.h header file can cause simillar errors like below
in some configurations.
"error: implicit declaration of function 'ERR_PTR'
[-Werror=implicit-function-declaration]"
This adds the missing include to ensure we can always include
the header.
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This function does a quick and easy read of an u32 value without any
kind of resource management code on the consumer side.
Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com>
Reviewed-by: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
nvmem_cell_read() is declared as void * if CONFIG_NVMEM is enabled, and
as char * otherwise. This can result in a build warning if CONFIG_NVMEM
is not enabled and a caller asigns the result to a type other than char *
without using a typecast. Use a consistent declaration to avoid the
problem.
Fixes: e2a5402ec7 ("nvmem: Add nvmem_device based consumer apis.")
Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch adds read/write apis which are based on nvmem_device. It is
common that the drivers like omap cape manager or qcom cpr driver to
access bytes directly at particular offset in the eeprom and not from
nvmem cell info in DT. These driver would need to get access to the nvmem
directly, which is what these new APIS provide.
These wrapper apis would help such users to avoid code duplication in
there drivers and also avoid them reading a big eeprom blob and parsing
it internally in there driver.
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Tested-by: Philipp Zabel <p.zabel@pengutronix.de>
Tested-by: Rajendra Nayak <rnayak@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch adds just consumers part of the framework just to enable easy
review.
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.
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: Maxime Ripard <maxime.ripard@free-electrons.com>
[Maxime Ripard: intial version of the framework]
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Tested-by: Philipp Zabel <p.zabel@pengutronix.de>
Tested-by: Rajendra Nayak <rnayak@codeaurora.org>
Signed-off-by: Greg 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: Maxime Ripard <maxime.ripard@free-electrons.com>
[Maxime Ripard: intial version of eeprom framework]
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Tested-by: Philipp Zabel <p.zabel@pengutronix.de>
Tested-by: Rajendra Nayak <rnayak@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Douglas Anderson
Andreas Färber
Yangtao Li
Linus Torvalds
Sebastian Reichel
Thomas Bogendoerfer
Fabrice Gasnier
Bartosz Golaszewski
Srinivas Kandagatla
Leonard Crestez
Guenter Roeck