The Elapsed Time Counter (ETC) registers are not buffered for reading.
If a 250ms tick occurs while data is being read out, the result can be
a combination of old and new values. This can occur at the byte level
(giving a time in the future) or the individual bit level (giving a
time in the past). We catch both these cases by reading until we get
two equal or consecutive values. After five unsuccessful attempts we
give up.
Signed-off-by: Thomas VanSelus <tvanselus@xes-inc.com>
Signed-off-by: Aaron Sierra <asierra@xes-inc.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch leverages the fact that all DS1682 registers are unsigned to
merge two return paths into one. It also introduces val_le as used in
ds1682_store() to merge two endianness conversions into one.
Signed-off-by: Aaron Sierra <asierra@xes-inc.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add all supported at24 variants to the of_match table.
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
The current expression using the || operator is always true because
dev->dev_state cannot be equal to two different values at the same time.
Fix this by replacing the || with &&.
Detected by CoverityScan, CID#1463042 ("Constant expression result")
Fixes: 8d52af6795 ("mei: speed up the power down flow")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>From the pci power documentation:
"The driver itself should not call pm_runtime_allow(), though. Instead,
it should let user space or some platform-specific code do that (user space
can do it via sysfs as stated above)..."
However, the S0ix residency cannot be reached without MEI device getting
into low power state. Hence, for mei devices that support D0i3, it's better
to make runtime power management mandatory and not rely on the system
integration such as udev rules.
This policy cannot be applied globally as some older platforms
were found to have broken power management.
Cc: <stable@vger.kernel.org> v4.13+
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Reviewed-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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: Bartosz Golaszewski <brgl@bgdev.pl>
Reviewed-by: Andy 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: Sven Van Asbroeck <svendev@arcx.com>
Signed-off-by: Bartosz 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 5478e478ee ("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: Sven Van Asbroeck <svendev@arcx.com>
Signed-off-by: Bartosz 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: Bartosz 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: Bartosz 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: Sven Van Asbroeck <svendev@arcx.com>
Signed-off-by: Bartosz 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: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
Remove the old and now unused write functions.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
Change return type of at24_translate_offset to *at24_client to make
member regmap accessible for subsequent patches of this series.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
This patch adds basic regmap support to be used by subsequent
patches of this series.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
This is a clean-up patch, no functional changes intended.
It removes the unused parameter of type "struct ddcb_requ*" from
the functions genwqe_user_vmap() and genwqe_user_vunmap().
Signed-off-by: Guilherme G. Piccoli <gpiccoli@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This is a clean-up patch, no functional changes intended.
It makes all defines uppercase, following a "tradition"
that helps to make code clearer.
Signed-off-by: Guilherme G. Piccoli <gpiccoli@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This is a clean-up patch, no functional changes intended.
It removes an unused variable from do_execute_ddcb() and
also renames the function free_user_pages(), prepending
"genwqe" prefix in order to clarify the code.
Signed-off-by: Guilherme G. Piccoli <gpiccoli@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Trivial fix to spelling mistake in dev_dbg debug message. Also
add in a missing comma.
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
