Currently the device is kept in D0, there is an opportunity
to save power by enabling runtime pm.

Device can be daisy chained from PMIC and we can't rely on I2C core
for auto resume/suspend. Driver will decide when to resume/suspend.
Reviewed-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NDivagar Mohandass <divagar.mohandass@intel.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Obtain the size of the EEPROM chip from DT if the "size" property is
specified for the device.
Suggested-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NDivagar Mohandass <divagar.mohandass@intel.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Allow the at24 driver to get configuration information from both OF and
ACPI by using the more generic device_property functions.
This change was inspired by the at25.c driver.

I have a custom board with a ST M24C02 EEPROM attached to an I2C bus.
With the following ACPI construct, this patch instantiates a working
instance of the driver.

Device (EEP0) {
 Name (_HID, "PRP0001")
 Name (_DSD, Package () {
  ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
  Package () {
   Package () {"compatible", Package () {"st,24c02"}},
   Package () {"pagesize", 16},
  },
 })
 Name (_CRS, ResourceTemplate () {
  I2cSerialBus (
   0x0057, ControllerInitiated, 400000,
   AddressingMode7Bit, "\\_SB.PCI0.I2C3", 0x00,
   ResourceConsumer,,)
 })
}
Signed-off-by: NBen Gardner <gardner.ben@gmail.com>
Reviewed-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

The at24 driver doesn't check if the chip is functional in its probe
function. This leads to instantiating devices that are not physically
present. For example the cape EEPROMs for BeagleBone Black are defined
in the device tree at four addresses on i2c2, but normally only one of
them is present.

If the userspace doesn't know the location in advance, it will need to
check if reading the nvmem attributes fails to determine which EEPROM
is actually there.

Try to read a single byte in probe() and bail-out with -ENODEV if the
read fails.
Signed-off-by: NBartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

loop_until_timeout() replaced a do {} while loop in the at24 driver
with a for loop which, under certain circumstances (such as heavy load
or low value of the write_timeout argument), can lead to the code in
the loop never being executed.

Make sure that at least one iteration of the code enclosed within
loop_until_timeout() is always executed.
Suggested-by: NWolfram Sang <wsa@the-dreams.de>
Signed-off-by: NBartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Add a new read function to the at24 driver allowing to retrieve the
factory-programmed mac address embedded in chips from the at24mac
family.

These chips can be instantiated similarily to the at24cs family,
except that there's no way of having access to both the serial number
and the mac address at the same time - the user must instantiate
either an at24cs or at24mac device as both special memory areas are
accessible on the same slave address.
Signed-off-by: NBartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

The chips from the at24cs family have two memory areas - a regular
read-write block and a read-only area containing the serial number.

The latter is visible on a different slave address (the address of the
rw memory block + 0x08). In order to access both blocks the user needs
to instantiate a regular at24c device for the rw block address and a
corresponding at24cs device on the serial number block address.

Add a function that allows to access the serial number and assign it
to at24->read_func if the chip allows serial number read operations
and the driver was passed the relevant flag for this device.
Signed-off-by: NBartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Split at24_eeprom_write() into three smaller functions - one for the
i2c operations and two for the smbus extensions (separate routines for
block and byte transfers). Assign them in at24_probe() depending on
the bus capabilities.

Also: in order to avoid duplications move code adjusting the count
argument into a separate function and use it for i2c and smbus block
writes (no need for a roll-over for byte writes as we're always
writing one byte).
Signed-off-by: NBartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Split at24_eeprom_read() into two smaller functions - one for the
i2c operations and one for the smbus extensions. Assign them in
at24_probe() depending on the bus capabilities.

Also: in order to avoid duplications move the comments related to
offset calculations above the at24_translate_offset() routine.
Signed-off-by: NBartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Before splitting the read/write routines into smaller, more
specialized functions, unduplicate some code in advance.

Use a 'for' loop instead of 'do while' when waiting for the previous
write to complete and hide it behind a macro.
Signed-off-by: NBartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

The first step in simplifying the read and write functions is to call
them via function pointers stored in at24_data. When we eventually
split the routines into smaller ones (depending on whether they use
smbus or i2c operations) we'll simply assign them to said pointers
instead of checking the flags at runtime every time we read/write.
Signed-off-by: NBartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Align the arguments in broken lines with the arguments list's opening
brackets and make checkpatch.pl happy by converting 'unsigned' into
'unsigned int'.
Signed-off-by: NBartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

In preparation for splitting at24_eeprom_write() & at24_eeprom_read()
into smaller, specialized routines move at24_read() below, so that it
won't be intertwined with the low-level EEPROM accessors.
Signed-off-by: NBartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

As part of the preparation for introducing support for more chips,
improve the readability of the device table by separating columns
with tabs.
Signed-off-by: NBartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

This patch moves to nvmem support in the driver to use callback instead
of regmap.
Signed-off-by: NSrinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

We cannot expect msleep(1) to actually sleep for a period shorter than
20 ms. Replace all calls to msleep() with usleep_range().
Signed-off-by: NBartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

The second check for I2C_FUNC_I2C is reduntant, so remove it.
Signed-off-by: NBartosz Golaszewski <bgolaszewski@baylibre.com>
[wsa: reworded commit message]
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Now that the AT24 uses the NVMEM framework, replace the
memory_accessor in the setup() callback with nvmem API calls.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Acked-by: NSrinivas Kandagatla <srinivas.kandagatla@linaro.org>
Tested-by: NSekhar Nori <nsekhar@ti.com>
Acked-by: NWolfram Sang <wsa@the-dreams.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add a regmap for accessing the EEPROM, and then use that with the
NVMEM framework. Set the NVMEM config structure to enable backward, so
that the 'eeprom' file in sys is provided by the framework.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Acked-by: NSrinivas Kandagatla <srinivas.kandagatla@linaro.org>
Tested-by: NBartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Use kobj_to_dev() instead of open-coding it.
Signed-off-by: NGeliang Tang <geliangtang@163.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

There is a 24c08 chip connected to i2c bus on Intel Galileo Gen2 board. Enable
it via ACPI ID INT3499.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

There is a 24c08 chip connected to i2c bus on Intel Galileo Gen2 board. Enable
it via ACPI ID INT3499.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

For i2c busses that support only SMBUS extensions, the eeprom at24
driver reads data from the device using the SMBus block, word or byte
read protocols depending on availability.

Replace the block read emulation from the driver with the
i2c_smbus_read_i2c_block_data_or_emulated call from i2c core.
Signed-off-by: NIrina Tirdea <irina.tirdea@intel.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

i2c_driver does not need to set an owner because i2c_register_driver()
will set it.
Signed-off-by: NKrzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

The change removes redundant sysfs binary file boundary check, since
this task is already done on caller side in fs/sysfs/file.c
Signed-off-by: NVladimir Zapolskiy <vz@mleia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

i2c_driver does not need to set an owner because i2c_register_driver()
will set it.
Signed-off-by: NKrzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

I have a at24 EEPROM connected via i2c bus provided by ISCH i2c
bus driver. This bus driver does not support
I2C_FUNC_SMBUS_WRITE_I2C_BLOCK and so I was looking for a way
to be able to write the eeprom. This patch adds support for
I2C_SMBUS_BYTE_DATA writing via i2c_smbus_write_byte_data.
It is quite slow, but it works.
Signed-off-by: NChristian Gmeiner <christian.gmeiner@gmail.com>
[wsa: s/use_smbuse_write/use_smbus_write/]
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

This change fixes a problem of infinite zero byte write() without
an error status, if there is an attempt to write a file bigger than
EEPROM size over sysfs interface.
Signed-off-by: NVladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Cc: Wolfram Sang <w.sang@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch moves the at24.h header from include/linux/i2c to
include/linux/platform_data and updates existing support accordingly.

It also fixes the following checkpatch warning:

    WARNING: please, no space before tabs
    #436: FILE: include/linux/platform_data/at24.h:31:
    + * ^Iu8 *mac_addr = ethernet_pdata->mac_addr;$
Signed-off-by: NVivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Use devm_kzalloc to make cleanup paths simpler
Signed-off-by: NNikolay Balandin <nbalandin@dev.rtsoft.ru>
Reviewed-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: NJingoo Han <jg1.han@samsung.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

CONFIG_HOTPLUG is going away as an option so __devexit is no
longer needed.
Signed-off-by: NBill Pemberton <wfp5p@virginia.edu>
Cc: "Michał Mirosław" <mirq-linux@rere.qmqm.pl>
Cc: Wolfram Sang <w.sang@pengutronix.de>
Cc: Eric Piel <eric.piel@tremplin-utc.net>
Cc: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

CONFIG_HOTPLUG is going away as an option so __devexit_p is no longer
needed.
Signed-off-by: NBill Pemberton <wfp5p@virginia.edu>
Cc: "Michał Mirosław" <mirq-linux@rere.qmqm.pl>
Cc: Wolfram Sang <w.sang@pengutronix.de>
Cc: Eric Piel <eric.piel@tremplin-utc.net>
Cc: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Side-effects happen when passing 0 to either io_limit or page_size. Give
an error in case of this misconfiguration.
Signed-off-by: NWolfram Sang <w.sang@pengutronix.de>
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>

Information about the pagesize and read-only-status may also come from
the devicetree. Parse this data, too, and act accordingly. While we are
here, change the initialization printout a bit. write_max is useful to
know to detect performance bottlenecks, the rest is superfluous.
Signed-off-by: NWolfram Sang <w.sang@pengutronix.de>
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>

I2C drivers can use the clientdata-pointer to point to private data. As I2C
devices are not really unregistered, but merely detached from their driver, it
used to be the drivers obligation to clear this pointer during remove() or a
failed probe(). As a couple of drivers forgot to do this, it was agreed that it
was cleaner if the i2c-core does this clearance when appropriate, as there is
no guarantee for the lifetime of the clientdata-pointer after remove() anyhow.
This feature was added to the core with commit
e4a7b9b0 to fix the faulty drivers.

As there is no need anymore to clear the clientdata-pointer, remove all current
occurrences in the drivers to simplify the code and prevent confusion.
Signed-off-by: NWolfram Sang <w.sang@pengutronix.de>
Acked-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: NGreg Kroah-Hartman <gregkh@suse.de>
Acked-by: NRichard Purdie <rpurdie@linux.intel.com>
Acked-by: NDmitry Torokhov <dtor@mail.ru>
Signed-off-by: NJean Delvare <khali@linux-fr.org>

Increase the portability of the at24 driver by letting it read from
EEPROM chips connected to cheap SMBus controllers that support neither
raw I2C messages nor even I2C block reads. All SMBus controllers
should support either word reads or byte reads, so read support
becomes universal, much like with the legacy "eeprom" driver.

Obviously, this only works with EEPROM chips up to AT24C16, that use
8-bit offset addressing. 16-bit offset addressing is almost impossible
to support on SMBus controllers.

I did not add universal support for writes, as I had no immediate need
for this, but it could be added later if needed (with the same
performance issue as byte and word reads have, of course.)
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Reviewed-by: NWolfram Sang <w.sang@pengutronix.de>
Cc: Konstantin Lazarev <klazarev@sbcglobal.net>

This allows bin_attr->read,write,mmap callbacks to check file specific data
(such as inode owner) as part of any privilege validation.
Signed-off-by: NChris Wright <chrisw@sous-sol.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Commit 6992f533 introduced this requirement.
Reported-by: NAlbrecht Dress <albrecht.dress@arcor.de>
Signed-off-by: NWolfram Sang <w.sang@pengutronix.de>
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NJean Delvare <khali@linux-fr.org>

Writes may take some time on EEPROMs, so for consecutive writes, we already
have a loop waiting for the EEPROM to become ready. Use such a loop for reads,
too, in case somebody wants to immediately read after a write. Detailed bug
report and test case can be found here:

http://article.gmane.org/gmane.linux.drivers.i2c/4660Reported-by: NAleksandar Ivanov <ivanov.aleks@gmail.com>
Signed-off-by: NWolfram Sang <w.sang@pengutronix.de>
Tested-by: NAleksandar Ivanov <ivanov.aleks@gmail.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: NJean Delvare <khali@linux-fr.org>

| drivers/misc/eeprom/at24.c:508: warning: assignment from incompatible pointer type
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Cc: Kevin Hilman <khilman@deeprootsystems.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Jean Delvare <khali@linux-fr.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>