Commit Graph

79 Commits

Author SHA1 Message Date
Thomas Bogendoerfer
8c2a2b8c2f
nvmem: core: add nvmem_device_find
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
2019-10-07 09:47:37 -07:00
Suzuki K Poulose
cfba5de9b9 drivers: Introduce device lookup variants by of_node
Introduce wrappers for {bus/driver/class}_find_device() to
locate devices by its of_node.

Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <maxime.ripard@bootlin.com>
Cc: dri-devel@lists.freedesktop.org
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: devicetree@vger.kernel.org
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Frank Rowand <frowand.list@gmail.com>
Cc: Heiko Stuebner <heiko@sntech.de>
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: linux-i2c@vger.kernel.org
Cc: linux-rockchip@lists.infradead.org
Cc: linux-spi@vger.kernel.org
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc: Takashi Iwai <tiwai@suse.com>
Cc: Alan Tull <atull@kernel.org>
Cc: linux-fpga@vger.kernel.org
Cc: Peter Rosin <peda@axentia.se>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Heiner Kallweit <hkallweit1@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Thor Thayer <thor.thayer@linux.intel.com>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Peter Rosin <peda@axentia.se>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Wolfram Sang <wsa@the-dreams.de> # I2C part
Acked-by: Moritz Fischer <mdf@kernel.org> # For FPGA part
Acked-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20190723221838.12024-3-suzuki.poulose@arm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-07-30 13:07:41 +02:00
Suzuki K Poulose
418e3ea157 bus_find_device: Unify the match callback with class_find_device
There is an arbitrary difference between the prototypes of
bus_find_device() and class_find_device() preventing their callers
from passing the same pair of data and match() arguments to both of
them, which is the const qualifier used in the prototype of
class_find_device().  If that qualifier is also used in the
bus_find_device() prototype, it will be possible to pass the same
match() callback function to both bus_find_device() and
class_find_device(), which will allow some optimizations to be made in
order to avoid code duplication going forward.  Also with that, constify
the "data" parameter as it is passed as a const to the match function.

For this reason, change the prototype of bus_find_device() to match
the prototype of class_find_device() and adjust its callers to use the
const qualifier in accordance with the new prototype of it.

Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Andreas Noever <andreas.noever@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Corey Minyard <minyard@acm.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: David Kershner <david.kershner@unisys.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: David Airlie <airlied@linux.ie>
Cc: Felipe Balbi <balbi@kernel.org>
Cc: Frank Rowand <frowand.list@gmail.com>
Cc: Grygorii Strashko <grygorii.strashko@ti.com>
Cc: Harald Freudenberger <freude@linux.ibm.com>
Cc: Hartmut Knaack <knaack.h@gmx.de>
Cc: Heiko Stuebner <heiko@sntech.de>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jonathan Cameron <jic23@kernel.org>
Cc: "James E.J. Bottomley" <jejb@linux.ibm.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michael Jamet <michael.jamet@intel.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Peter Oberparleiter <oberpar@linux.ibm.com>
Cc: Sebastian Ott <sebott@linux.ibm.com>
Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc: Yehezkel Bernat <YehezkelShB@gmail.com>
Cc: rafael@kernel.org
Acked-by: Corey Minyard <minyard@acm.org>
Acked-by: David Kershner <david.kershner@unisys.com>
Acked-by: Mark Brown <broonie@kernel.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Acked-by: Wolfram Sang <wsa@the-dreams.de> # for the I2C parts
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-24 05:22:31 +02:00
Srinivas Kandagatla
ae0c2d7255 nvmem: core: add NVMEM_SYSFS Kconfig
Many nvmem providers are not very keen on having default sysfs
nvmem entry, as most of the usecases for them are inside kernel
itself. And in some cases read/writes to some areas in nvmem are
restricted and trapped at secure monitor level, so accessing them
from userspace would result in board reboots.

This patch adds new NVMEM_SYSFS Kconfig to make binary sysfs entry
an optional one. This provision will give more flexibility to users.
This patch also moves existing sysfs code to a new file so that its
not compiled in when its not really required.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Gaurav Kohli <gkohli@codeaurora.org>
Tested-by: Gaurav Kohli <gkohli@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-04-25 19:44:33 +02:00
Jorge Ramirez-Ortiz
2fe518fecb nvmem: core: fix read buffer in place
When the bit_offset in the cell is zero, the pointer to the msb will
not be properly initialized (ie, will still be pointing to the first
byte in the buffer).

This being the case, if there are bits to clear in the msb, those will
be left untouched while the mask will incorrectly clear bit positions
on the first byte.

This commit also makes sure that any byte unused in the cell is
cleared.

Signed-off-by: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-04-25 19:43:12 +02:00
Fabrice Gasnier
0a9b2d1ce4 nvmem: core: add nvmem_cell_read_u16
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>
2019-04-25 19:43:12 +02:00
Bartosz Golaszewski
f4853e1c32 nvmem: core: don't check the return value of notifier chain call
blocking_notifier_call_chain() returns the value returned by the last
registered callback. A positive return value doesn't indicate an error
and an nvmem device should correctly register irrespective of any
notifier callback failures. Drop the retval check.

Fixes: bee1138bea ("nvmem: add a notifier chain")
Cc: stable@vger.kernel.org
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Acked-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-02-19 14:50:11 +01:00
Alban Bedel
9bfd8198ba nvmem: core: Avoid useless iterations in nvmem_cell_get_from_lookup()
Once the correct cell has been found there is no need to continue
iterating, just stop there. While at it replace the goto used to leave
the loop with simple break statements.

Signed-off-by: Alban Bedel <albeu@free.fr>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-01-31 16:24:15 +01:00
Alban Bedel
73e9dc4d56 nvmem: core: Fix device reference leak
__nvmem_device_get() make use of bus_find_device() to get the relevant
device and this function increase the reference count of the device
found, however this is not accounted for anywhere. Fix
__nvmem_device_get() and __nvmem_device_put() to properly release this
reference count.

Signed-off-by: Alban Bedel <albeu@free.fr>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-01-31 16:24:15 +01:00
Alban Bedel
95b65195d5 nvmem: core: Always reference the device returned by nvmem_device_get()
In nvmem_device_get(), when the device lookup fails with DT it
currently fallback on nvmem_find() which is wrong for two reasons.
First nvmem_find() return NULL when nothing is found instead of an
ERR_PTR. But nvmem_find() also just lookup the device, it doesn't
reference the module and increment the reference count like it is done
in the DT path.

To fix this we replace the call to nvmem_find() with a call to
__nvmem_device_get() which does all the referencing and return a
proper ERR_PTR in case of error.

Signed-off-by: Alban Bedel <albeu@free.fr>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-01-31 16:24:14 +01:00
Alban Bedel
d4e7fef1a9 nvmem: core: Properly handle connection ID in of_nvmem_device_get()
of_nvmem_device_get() would crash if NULL was passed as a connection
ID. Rework this to use the usual sementic of assuming the first
connection when no connection ID is given.

Furthermore of_nvmem_device_get() would return -EINVAL when it failed
to resolve the connection, making it impossible to properly implement
an optional connection. Return -ENOENT instead to let the caller know
that the connection doesn't exists.

Signed-off-by: Alban Bedel <albeu@free.fr>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-01-31 16:24:14 +01:00
Alban Bedel
1c83267473 nvmem: core: Fix cell lookup when no cell is found
If the cell list is not empty and nvmem_find_cell_by_node/name() is
called for a cell that is not present in the list they will return an
invalid pointer instead of NULL. This happen because
list_for_each_entry() stop once it reach the list head again, but as
the list head is not contained in a struct nvmem_cell the iteration
variable then contains an invalid value.

This is easily solved by using a variable to iterate over the list and
one to return the cell found.

Signed-off-by: Alban Bedel <albeu@free.fr>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-01-31 16:24:14 +01:00
Alban Bedel
5087cc198e nvmem: core: Fix of_nvmem_cell_get() for optional cells
of_nvmem_cell_get() should return -ENOENT when a cell isn't defined,
otherwise callers can't distinguish between a missing cell and other
errors.

Signed-off-by: Alban Bedel <albeu@free.fr>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-01-31 16:24:14 +01:00
Alban Bedel
1716cfe8be nvmem: core: Set the provider read-only when no write callback is given
If no write callback is given the device should be marked as read-only.
While at it also move from a bit or to a logical or as that is a logical
expression.

Signed-off-by: Alban Bedel <albeu@free.fr>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-01-31 16:24:14 +01:00
Bartosz Golaszewski
517f14d9cf nvmem: add new config option
We want to add nvmem support for MTD. TI DaVinci is the first platform
that will be using it, but only in non-DT mode. In order not to
introduce any new interface to supporting of which we would have to
commit - add a new config option that tells nvmem not to use the DT
node of the parent device.

This way we won't be creating nvmem devices corresponding with MTD
partitions defined in device tree. By default MTD will set this new
field to true.

Once a set of bindings for MTD nvmem cells is agreed upon, we'll be
able to remove this option.

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>
2018-12-06 15:45:46 +01:00
Andy Shevchenko
a8b44d5d2e nvmem: Move nvmem_type_str array to its only user
Since we put static variable to a header file it's copied to each module
that includes the header. But not all of them are actually using it.

Move nvmem_type_str array to its only user to make a compiler happy:

In file included from include/linux/rtc.h:18,
                 from drivers/rtc/rtc-proc.c:15:
include/linux/nvmem-provider.h:29:27: warning: 'nvmem_type_str'
defined but not used [-Wunused-const-variable=]
 static const char * const nvmem_type_str[] = {
                           ^~~~~~~~~~~~~~

Suggested-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Suggested-by: Joe Perches <joe@perches.com>
Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-12-06 15:45:46 +01:00
Alexandre Belloni
1668845366 nvmem: add type attribute
Add a type attribute so userspace is able to know how the data is stored as
this can help taking the correct decision when selecting which device to
use. This will also help program display the proper warnings when burning
fuses for example.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-12-06 15:45:45 +01:00
Srinivas Kandagatla
0749aa25af nvmem: core: fix regression in of_nvmem_cell_get()
NVMEM DT support seems to be totally broken after
commit e888d445ac ("nvmem: resolve cells from DT at registration time")
Fix this!

Index used in of_nvmem_cell_get() to find cell is specific to
consumer, It can not be used for searching the cell in provider.
Use device_node instead of this to find the matching cell in device
tree case.

Fixes: e888d445ac ("nvmem: resolve cells from DT at registration time")
Reported-by: Niklas Cassel <niklas.cassel@linaro.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Tested-by: Niklas Cassel <niklas.cassel@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-11-11 09:15:29 -08:00
Arnd Bergmann
3c53e2352a nvmem: hide unused nvmem_find_cell_by_index function
nvmem_find_cell_by_index() is only called from inside an #ifdef,
so we get a build warning without CONFIG_OF:

drivers/nvmem/core.c:496:1: error: 'nvmem_find_cell_by_index' defined but not used [-Werror=unused-function]

Move it into the same #ifdef as the caller to avoid the warning.

Fixes: e888d445ac ("nvmem: resolve cells from DT at registration time")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-10-15 15:56:15 +02:00
Bartosz Golaszewski
cccb3b19e7 nvmem: fix nvmem_cell_get_from_lookup()
We check if the pointer returned by __nvmem_device_get() is not NULL
while we should actually check if it is not IS_ERR(nvmem). Fix it.

While we're at it: fix the next error path where we should assign an
error value to cell before returning.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-10-15 15:56:15 +02:00
Rob Herring
badcdff107 nvmem: Convert to using %pOFn instead of device_node.name
In preparation to remove the node name pointer from struct device_node,
convert printf users to use the %pOFn format specifier.

Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Rob Herring <robh@kernel.org>
[srinivas: rebased on top of next]
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-10-15 15:56:14 +02:00
Srinivas Kandagatla
ef92ab3001 nvmem: make nvmem_add_cells() static
Now we have new api nvmem_add/del_cell_table() we do not want users to use
nvmem_add_cells() anymore. So mark it accordingly. I guess it was missed in
original cleanup patch.

This also fixes below warning:
core.c:355:5: warning: no previous prototype for 'nvmem_add_cells'
 [-Wmissing-prototypes]

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-28 15:14:55 +02:00
Bartosz Golaszewski
e7e07f4f7b nvmem: use octal permissions instead of constants
Checkpatch emits a warning when using symbolic permissions. Use octal
permissions instead.

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>
2018-09-28 15:14:55 +02:00
Bartosz Golaszewski
48f63a2c10 nvmem: fix commenting style
Remove a redundant '*/' as pointed out by checkpatch.

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>
2018-09-28 15:14:55 +02:00
Bartosz Golaszewski
165589f0cb nvmem: make the naming of arguments in nvmem_cell_get() consistent
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>
2018-09-28 15:14:55 +02:00
Bartosz Golaszewski
b1c1db9883 nvmem: use SPDX license identifiers
Use SPDX license identiefiers to core nvmem files and remove GPL 2.0
license boilerplate.

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>
2018-09-28 15:14:54 +02:00
Bartosz Golaszewski
bee1138bea nvmem: add a notifier chain
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>
2018-09-28 15:14:54 +02:00
Bartosz Golaszewski
506157be06 nvmem: add support for cell lookups from machine code
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>
2018-09-28 15:14:54 +02:00
Bartosz Golaszewski
e888d445ac nvmem: resolve cells from DT at registration time
Currently we're creating a new cell structure everytime a DT user
calls nvmem_cell_get().

Change this behavior by resolving the cells during nvmem provider
registration and adding all cells to the provider's list. Make
of_nvmem_cell_get() just parse the phandle and look the cell up
in the relevant provider's list.

Don't drop the cell in nvmem_cell_put().

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>
2018-09-28 15:14:54 +02:00
Bartosz Golaszewski
b985f4cba6 nvmem: add support for cell info
Add new structs and routines allowing users to define nvmem cells from
machine code. This global list of entries is parsed when a provider
is registered and cells are associated with the relevant nvmem_device
struct.

A possible improvement for the future is to allow users to register
cell tables after the nvmem provider has been registered by updating
the cell list at each call to nvmem_(add|del)_cell_table().

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>
2018-09-28 15:14:54 +02:00
Bartosz Golaszewski
c7235ee3f4 nvmem: remove the global cell list
Nvmem subsystem keeps a global list of cells that, for non-DT systems,
can only be referenced by cell name, which makes it impossible to have
more than one nvmem device with cells named the same.

This patch makes every nvmem device the owner of the list of its cells.
This effectively removes the support for non-DT systems, but it will
be reintroduced following a different approach in subsequent patches.

This isn't a problem as support for board files in nvmem is currently
broken anyway: any user that would try to get an nvmem cell from the
global cell list would remove the cell after the calling
nvmem_cell_put(). This can cause anything from a subsequent user not
being able to get the cell to double free errors if more users hold
reference to the same cell at the same time.

Fortunately there are no such users which allows us to rework this part.

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>
2018-09-28 15:14:54 +02:00
Bartosz Golaszewski
bf58e8820c nvmem: change the signature of nvmem_unregister()
We switched the nvmem framework to using kref instead of manually
checking the current number of users in nvmem_unregister() so this
function can no longer fail. We also converted all remaining users
that still checked the return value of nvmem_unregister() to using
devm_nvmem_register(). Make the routine return void.

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>
2018-09-28 15:14:54 +02:00
Bartosz Golaszewski
c1de7f43bd nvmem: use kref
Use kref for reference counting. Use an approach similar to the one
seen in the common clock subsystem: don't actually destroy the nvmem
device until the last user puts it. This way we can get rid of the
users check from nvmem_unregister().

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>
2018-09-28 15:14:54 +02:00
Bartosz Golaszewski
fa72d847d6 nvmem: check the return value of nvmem_add_cells()
This function can fail so check its return value in nvmem_register()
and act accordingly.

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>
2018-09-28 15:14:54 +02:00
Bartosz Golaszewski
f9fcb7e36c nvmem: remove a stray newline
There are two empty lines between devm_nvmem_unregister() and
__nvmem_device_get(). Remove one.

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>
2018-09-28 15:14:53 +02:00
Bartosz Golaszewski
1852183e14 nvmem: use list_for_each_entry_safe in nvmem_device_remove_all_cells()
Use the provided helper for iterating over list entries without having
to use the list_entry() macro.

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>
2018-09-28 15:14:53 +02:00
Bartosz Golaszewski
5db652c9f3 nvmem: remove the name field from struct nvmem_device
This field is never set and is only used in a single error message.
Remove the field and use nvmem_dev_name() instead.

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>
2018-09-28 15:14:53 +02:00
Bartosz Golaszewski
d7b9fd1669 nvmem: provide nvmem_dev_name()
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>
2018-09-28 15:14:53 +02:00
Srinivas Kandagatla
ca6ac25cec nvmem: core: return error code instead of NULL from nvmem_device_get
nvmem_device_get() should return ERR_PTR() on error or valid pointer
on success, but one of the code path seems to return NULL, so fix it.

Reported-by: Niklas Cassel <niklas.cassel@linaro.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-12 09:46:46 +02:00
Greg Kroah-Hartman
83cf9cd6d5 Merge 4.18-rc5 into char-misc-next
We want the char-misc fixes in here as well.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-07-16 09:04:54 +02:00
Srinivas Kandagatla
fc82975aea nvmem: core: remove unused nvmem_device ncells member
nvmem ncells can be over written by calling nvmem_add_cells()
multiple times. I see there is no real point of maintaining count
of cells when we have a list of cell.

Remove this to avoid any confusion!

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-07-07 17:30:46 +02:00
Douglas Anderson
87ed1405ef nvmem: Don't let a NULL cell_id for nvmem_cell_get() crash us
In commit ca04d9d3e1 ("phy: qcom-qusb2: New driver for QUSB2 PHY on
Qcom chips") you can see a call like:

  devm_nvmem_cell_get(dev, NULL);

Note that the cell ID passed to the function is NULL.  This is because
the qcom-qusb2 driver is expected to work only on systems where the
PHY node is hooked up via device-tree and is nameless.

This works OK for the most part.  The first thing nvmem_cell_get()
does is to call of_nvmem_cell_get() and there it's documented that a
NULL name is fine.  The problem happens when the call to
of_nvmem_cell_get() returns -EINVAL.  In such a case we'll fall back
to nvmem_cell_get_from_list() and eventually might (if nvmem_cells
isn't an empty list) crash with something that looks like:

 strcmp
 nvmem_find_cell
 __nvmem_device_get
 nvmem_cell_get_from_list
 nvmem_cell_get
 devm_nvmem_cell_get
 qusb2_phy_probe

There are several different ways we could fix this problem:

One could argue that perhaps the qcom-qusb2 driver should be changed
to use of_nvmem_cell_get() which is allowed to have a NULL name.  In
that case, we'd need to add a patche to introduce
devm_of_nvmem_cell_get() since the qcom-qusb2 driver is using devm
managed resources.

One could also argue that perhaps we could just add a name to
qcom-qusb2.  That would be OK but I believe it effectively changes the
device tree bindings, so maybe it's a no-go.

In this patch I have chosen to fix the problem by simply not crashing
when a NULL cell_id is passed to nvmem_cell_get().

NOTE: that for the qcom-qusb2 driver the "nvmem-cells" property is
defined to be optional and thus it's expected to be a common case that
we would hit this crash and this is more than just a theoretical fix.

Fixes: ca04d9d3e1 ("phy: qcom-qusb2: New driver for QUSB2 PHY on Qcom chips")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-07-07 17:30:25 +02:00
Mathieu Malaterre
50808bfcc1 nvmem: properly handle returned value nvmem_reg_read
Function nvmem_reg_read can return a non zero value indicating an error.
This returned value must be read and error propagated to
nvmem_cell_prepare_write_buffer. Silence the following gcc warning (W=1):

drivers/nvmem/core.c:1093:9: warning: variable 'rc' set but
 not used [-Wunused-but-set-variable]

Signed-off-by: Mathieu Malaterre <malat@debian.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-05-14 16:20:48 +02:00
Srinivas Kandagatla
b378c77934 nvmem: core: describe add missing dev function parameter
Document dev parameter which not described in devm_nvmem_unregister
and devm_nvmem_register functions.

Fix below warnings when kernel is compiled with W=1
drivers/nvmem/core.c:579: warning: Function parameter or member
 'dev' not described in 'devm_nvmem_register'
nvmem/core.c:615: warning: Function parameter or member 'dev'
 not described in 'devm_nvmem_unregister'

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-05-14 16:20:48 +02:00
Andrew Lunn
b3db17e4b8 drivers: nvmem: Export nvmem_add_cells()
Not all platforms use device tree. It is useful to be able to add
cells to a NVMEM device from code. Export nvmem_add_cells() so making
this possible.

This required changing the parameters a bit, so that just the cells
and the number of cells are passed, not the whole nvmem config
structure.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-05-14 16:20:48 +02:00
Andrey Smirnov
f1f50eca5f nvmem: Introduce devm_nvmem_(un)register()
Introduce devm_nvmem_register()/devm_nvmem_unregister() to make
.remove() unnecessary in trivial drivers.

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: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-03-14 19:28:13 +01:00
Andrey Smirnov
fd0f4906a3 nvmem: core: Allow specifying device name verbatim
Add code to allow avoid having nvmem core append a numeric suffix to
the end of the name by passing config->id of -1.

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: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-03-14 19:28:13 +01:00
Heiner Kallweit
fc2f997035 nvmem: core: switch to device_property_present for reading property "read-only"
Switch to more generic device_property_present to consider also non-DT
properties.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-12-19 10:39:33 +01:00
Heiner Kallweit
99897efd5a nvmem: core: let stride and word_size default to 1
If the caller doesn't set stride and/or word_size in struct nvmem_config
then nvmem_register accepts this but we may face strange effects later
due to both values being 0. Therefore use 1 as default for both values.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-12-19 10:39:33 +01:00
Lukas Wunner
9f3044c38c nvmem: core: Deduplicate bus_find_device() by name matching
No need to reinvent the wheel, we have bus_find_device_by_name().

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-12-19 10:39:33 +01:00