[ Upstream commit 37cf28d3b5bca1b532a0b6aac722e7f2788a9294 ]

Works with ST M24M02.
Signed-off-by: NAdrian Bunk <bunk@kernel.org>
Signed-off-by: NBartosz Golaszewski <brgl@bgdev.pl>
Signed-off-by: NSasha Levin <sashal@kernel.org>

Provide a flexible way to determine the addressing bits of eeprom.
Pass the addressing bits to driver through address-width property.
Signed-off-by: NAlan Chiang <alanx.chiang@intel.com>
Signed-off-by: NAndy Yeh <andy.yeh@intel.com>
Signed-off-by: NBartosz Golaszewski <brgl@bgdev.pl>

Move the code responsible for creating the dummy i2c clients used by
chips taking multiple slave addresses to a separate function.
Signed-off-by: NBartosz Golaszewski <brgl@bgdev.pl>
Reviewed-by: NPeter Rosin <peda@axentia.se>

This allows us to drop two opencoded for loops. We also don't need to
check if the i2c client is NULL before calling i2c_unregister_device().
Signed-off-by: NBartosz Golaszewski <brgl@bgdev.pl>
Reviewed-by: NPeter Rosin <peda@axentia.se>

We now have a managed variant of nvmem_register(). Use it
in at24_probe().
Signed-off-by: NBartosz Golaszewski <brgl@bgdev.pl>
Reviewed-by: NPeter Rosin <peda@axentia.se>

Commit feb2f19b ("eeprom: at24: move platform data processing into
a separate routine") introduced a bug where we incorrectly retireve the
at24_chip_data structure. Remove the unnecessary ampersand operator.

Fixes: feb2f19b ("eeprom: at24: move platform data processing into a separate routine")
Reported-by: NVadim Pasternak <vadimp@mellanox.com>
Signed-off-by: NBartosz Golaszewski <brgl@bgdev.pl>

Commit feb2f19b ("eeprom: at24: move platform data processing into
a separate routine") introduced a bug where we incorrectly retireve the
at24_chip_data structure. Remove the unnecessary ampersand operator.

Fixes: feb2f19b ("eeprom: at24: move platform data processing into a separate routine")
Reported-by: NVadim Pasternak <vadimp@mellanox.com>
Signed-off-by: NBartosz Golaszewski <brgl@bgdev.pl>

Replace the GPL (or later) header with the SPDX identifier
for GPL-2.0+.
Signed-off-by: NBartosz Golaszewski <brgl@bgdev.pl>
Tested-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Save one call and make code prettier by checking the i2c functionality
in the beginning of at24_probe(), saving the relevant values and
reusing them later.
Signed-off-by: NBartosz Golaszewski <brgl@bgdev.pl>
Tested-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Align the broken line with the opening parenthesis to stay consistent
with the rest of the driver code.
Signed-off-by: NBartosz Golaszewski <brgl@bgdev.pl>
Tested-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Remove the newline between the nvmem registration and its return value
check. This is consistent with the rest of the driver code.

Add a missing newline between two pdata checks to stay consistent with
all the others.
Signed-off-by: NBartosz Golaszewski <brgl@bgdev.pl>
Tested-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The code in at24_probe() is pretty mangled. It can be cleaned up a bit
by doing things one by one.

Let's group the code by logic: parse and verify pdata, initialize the
regmap, allocate and fill the fields of at24_data, allocate dummy i2c
devices, initialize pm & register with nvmem.
Signed-off-by: NBartosz Golaszewski <brgl@bgdev.pl>
Tested-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Not all fields from at24_platform_data are needed in at24_data. Let's
keep just the ones we need and not carry the whole platform_data
structure all the time.
Signed-off-by: NBartosz Golaszewski <brgl@bgdev.pl>
Tested-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This driver can receive its device data from different sources
depending on the system. Move the entire code processing platform data,
device tree and acpi into a separate function.
Signed-off-by: NBartosz Golaszewski <brgl@bgdev.pl>
Tested-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Use the new probe() style for i2c drivers.
Signed-off-by: NBartosz Golaszewski <brgl@bgdev.pl>
Tested-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Use a helper function for accessing the device struct of the base
i2c client. This routine is named in a way that reflects its purpose
unlike the previously hand-coded dereferencing.
Signed-off-by: NBartosz Golaszewski <brgl@bgdev.pl>
Tested-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Use a helper variable for the size we want to allocate with
devm_kzalloc() and save an ugly line break.
Signed-off-by: NBartosz Golaszewski <brgl@bgdev.pl>
Tested-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

We use the &client->dev construct all over in at24_probe(). Use
a helper variable which is more readable and allows to avoid a couple
unnecessary line breaks.
Signed-off-by: NBartosz Golaszewski <brgl@bgdev.pl>
Tested-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Reflect the purpose of this variable: it contains platform data so name
it such.
Signed-off-by: NBartosz Golaszewski <brgl@bgdev.pl>
Tested-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

As preparation for at24_probe() refactoring: rename at24_get_pdata()
to at24_properties_to_pdata(). We're doing it because we'll move the
pdata parsing code into a separate function which will be called
at24_get_pdata(). Current routine with that name actually parses
the device properties so change its name to reflect its purpose.
Signed-off-by: NBartosz Golaszewski <brgl@bgdev.pl>
Tested-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

We support certain models the size of which is not a power of 2. This
is not a reason to emit a warning.
Signed-off-by: NBartosz Golaszewski <brgl@bgdev.pl>
Tested-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When zeroing structs, use "{ }" everywhere.
Signed-off-by: NBartosz Golaszewski <brgl@bgdev.pl>
Tested-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

We can reuse ret instead of defining a loop-local status variable.
Signed-off-by: NBartosz Golaszewski <brgl@bgdev.pl>
Tested-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

We can reuse ret instead of defining a loop-local status variable.
Signed-off-by: NBartosz Golaszewski <brgl@bgdev.pl>
Tested-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

These are just two left-overs from times when this driver was bigger.

They are not really useful anymore. Remove them.
Signed-off-by: NBartosz Golaszewski <brgl@bgdev.pl>
Tested-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Arrange declarations of local variables by line length as visually
it's easier to read.
Signed-off-by: NBartosz Golaszewski <brgl@bgdev.pl>
Tested-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This structure only needs to exist during the call to nvmem_register().
Signed-off-by: NBartosz Golaszewski <brgl@bgdev.pl>
Tested-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

We use our own mutex for locking. Disable the regmap-specific locking.
Signed-off-by: NBartosz Golaszewski <brgl@bgdev.pl>
Tested-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add all supported at24 variants to the of_match table.
Signed-off-by: NBartosz Golaszewski <brgl@bgdev.pl>
Reviewed-by: NJavier Martinez Canillas <javierm@redhat.com>

AT24 EEPROMs have a write-protect pin, which - when pulled high -
inhibits writes to the upper quadrant of memory (although it has been
observed that on some chips it disables writing to the entire memory
range).

On some boards, this pin is connected to a GPIO and pulled high by
default, which forces the user to manually change its state before
writing. On linux this means that we either need to hog the line all
the time, or set the GPIO value before writing from outside of the
at24 driver.

Make the driver check if the write-protect GPIO was defined in the
device tree and pull it low whenever writing to the EEPROM.
Signed-off-by: NBartosz Golaszewski <brgl@bgdev.pl>
Reviewed-by: NAndy Shevchenko <andy.shevchenko@gmail.com>

The chip size passed via devicetree, i2c, or acpi device ids is now no
longer limited to a power of two. So the temporary fix can be removed.
Signed-off-by: NSven Van Asbroeck <svendev@arcx.com>
Signed-off-by: NBartosz Golaszewski <brgl@bgdev.pl>

Fundamental properties such as capacity and page size differ among
at24-type chips. But these chips do not have an id register, so this
can't be discovered at runtime.

Traditionally, at24-type eeprom properties were determined in two ways:
- by passing a 'struct at24_platform_data' via platform_data, or
- by naming the chip type in the devicetree, which passes a 'magic
  number' to probe(), which is then converted to a 'struct
  at24_platform_data'.

Recently a bug was discovered because the magic number rounds down all
chip sizes to the lowest power of two. This was addressed by
a work-around commit 5478e478 ("eeprom: at24: correctly set the
size for at24mac402"), with the wish that magic numbers should over
time be converted to structs.

This patch replaces the magic numbers with 'struct at24_chip_data'.
Signed-off-by: NSven Van Asbroeck <svendev@arcx.com>
Signed-off-by: NBartosz Golaszewski <brgl@bgdev.pl>

A regmap_config struct is pretty big and declaring two of them
statically just to tweak the reg_bits value adds unnecessary bloat.

Declare the regmap config locally in at24_probe() instead.

Bloat-o-meter output for ARM:

add/remove: 0/2 grow/shrink: 1/0 up/down: 4/-272 (-268)
Function                                     old     new   delta
at24_probe                                  1560    1564      +4
regmap_config_8                              136       -    -136
regmap_config_16                             136       -    -136
Total: Before=7012, After=6744, chg -3.82%
Signed-off-by: NBartosz Golaszewski <brgl@bgdev.pl>

There are a couple symbols defined in the driver source file which are
missing the at24_ prefix. This patch fixes that.

For module params: use module_param_named() in order to not break
userspace.
Signed-off-by: NBartosz Golaszewski <brgl@bgdev.pl>

Fix issues reported by checkpatch for at24.c.
Signed-off-by: NBartosz Golaszewski <brgl@bgdev.pl>

Some multi-address eeproms in the at24 family may not automatically
roll-over reads to the next slave address. On those eeproms, reads
that straddle slave boundaries will not work correctly.

Solution:
Mark such eeproms with a flag that prevents reads straddling
slave boundaries. Add the AT24_FLAG_NO_RDROL flag to the eeprom
entry in the device_id table, or add 'no-read-rollover' to the
eeprom devicetree entry.

Note that I have not personally enountered an at24 chip that
does not support read rollovers. They may or may not exist.
However, my hardware requires this functionality because of
a quirk.
Signed-off-by: NSven Van Asbroeck <svendev@arcx.com>
Signed-off-by: NBartosz Golaszewski <brgl@bgdev.pl>

Remove remaining now unneeded code dealing with SMBUS details.
Signed-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: NBartosz Golaszewski <brgl@bgdev.pl>

Remove the old and now unused read functions.
Signed-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: NBartosz Golaszewski <brgl@bgdev.pl>

Add regmap-based read function and instead of using three different
read functions (standard, mac, serial) use just one and factor out the
read offset adjustment for mac and serial to at24_adjust_read_offset.
Signed-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: NBartosz Golaszewski <brgl@bgdev.pl>

Remove the old and now unused write functions.
Signed-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: NBartosz Golaszewski <brgl@bgdev.pl>