include/linux/i2c is not for client devices. Move the header file to a
more appropriate location.
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

The TCA9554 doesn't work with the pcf857x driver, trying to change the direction
gives a NAK bailout error.

TCA9554 is similar to the PCA9554, thus change the driver.
Signed-off-by: NAnders Darander <anders@chargestorm.se>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

This tries to simplify the use of CONFIG_GPIOLIB_IRQCHIP when
using threaded interrupts: add a new call
gpiochip_irqchip_add_nested() to indicate that we're dealing
with a nested rather than a chained irqchip, then create a
separate gpiochip_set_nested_irqchip() to mirror
the gpiochip_set_chained_irqchip() call to connect the
parent and child interrupts.

In the nested case gpiochip_set_nested_irqchip() does nothing
more than call irq_set_parent() on each valid child interrupt,
which has little semantic effect in the kernel, but this is
probably still formally correct.

Update all drivers using nested interrupts to use
gpiochip_irqchip_add_nested() so we can now see clearly
which these users are.

The DLN2 driver can drop its specific hack with
.irq_not_threaded as we now recognize whether a chip is
threaded or not from its use of gpiochip_irqchip_add_nested()
signature rather than from inspecting .can_sleep.

We rename the .irq_parent to .irq_chained_parent since this
parent IRQ is only really kept around for the chained
interrupt handlers.

Cc: Lars Poeschel <poeschel@lemonage.de>
Cc: Octavian Purdila <octavian.purdila@intel.com>
Cc: Daniel Baluta <daniel.baluta@intel.com>
Cc: Bin Gao <bin.gao@linux.intel.com>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Ajay Thomas <ajay.thomas.david.rajamanickam@intel.com>
Cc: Semen Protsenko <semen.protsenko@globallogic.com>
Cc: Alexander Stein <alexander.stein@systec-electronic.com>
Cc: Phil Reid <preid@electromag.com.au>
Cc: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Cc: Patrice Chotard <patrice.chotard@st.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

The reset values for all the PCF lines are high and hence on
shutdown we should drive all the lines high in order to
bring it to the reset state.

This is actually required since PCF doesn't have a reset
line and even after warm reset (by invoking "reboot" in
prompt) the PCF lines maintains it's previous programmed
state. This becomes a problem if the boards are designed to
work with the default initial state.

DRA7XX_evm uses PCF8575 and one of the PCF output lines
feeds to MMC/SD VDD and this line should be driven high in order
for the MMC/SD to be detected.  This line is modelled as
regulator and the hsmmc driver takes care of enabling and
disabling it. In the case of 'reboot', during shutdown path
as part of it's cleanup process the hsmmc driver disables
this regulator. This makes MMC *boot* not functional.

Fix it by driving all the pcf lines high.

This patch was sent long back
(https://patchwork.ozlabs.org/patch/420382/)
But there was a concern that contention might occur if the
PCF shutdown handler is invoked before the shutdown handler
of the PCF's consumers. In that case PCF shutdown handler can't
drive all the pcf lines high without knowing if the PCF
consumers are still active.

However commit 52cdbdd4 ("driver core: correct device's
shutdown order") will make sure shutdown handler of PCF's
consumers are invoked before invoking the shutdown
handler of PCF. So it should be safe to merge this now.
Signed-off-by: NKishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: NSekhar Nori <nsekhar@ti.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Use devm_gpiochip_add_data() for GPIO registration and clean the
error path.
Signed-off-by: NLaxman Dewangan <ldewangan@nvidia.com>

This makes the driver use the data pointer added to the gpio_chip
to store a pointer to the state container instead of relying on
container_of().

Cc: Grygorii Strashko <grygorii.strashko@ti.com>
Cc: George Cherian <george.cherian@ti.com>
Cc: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

As we want gpio_chip .get() calls to be able to return negative
error codes and propagate to drivers, we need to go over all
drivers and make sure their return values are clamped to [0,1].
We do this by using the ret = !!(val) design pattern.

Also start returning the error code if something fails, as the
end of the series augment the core to support this.

Cc: Grygorii Strashko <grygorii.strashko@ti.com>
Cc: George Cherian <george.cherian@ti.com>
Cc: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Fixes: 58383c78 ("gpio: change member .dev to .parent")
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

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: NLinus Walleij <linus.walleij@linaro.org>

The name .dev in a struct is normally reserved for a struct device
that is let us say a superclass to the thing described by the struct.
struct gpio_chip stands out by confusingly using a struct device *dev
to point to the parent device (such as a platform_device) that
represents the hardware. As we want to give gpio_chip:s real devices,
this is not working. We need to rename this member to parent.

This was done by two coccinelle scripts, I guess it is possible to
combine them into one, but I don't know such stuff. They look like
this:

@@
struct gpio_chip *var;
@@
-var->dev
+var->parent

and:

@@
struct gpio_chip var;
@@
-var.dev
+var.parent

and:

@@
struct bgpio_chip *var;
@@
-var->gc.dev
+var->gc.parent

Plus a few instances of bgpio that I couldn't figure out how
to teach Coccinelle to rewrite.

This patch hits all over the place, but I *strongly* prefer this
solution to any piecemal approaches that just exercise patch
mechanics all over the place. It mainly hits drivers/gpio and
drivers/pinctrl which is my own backyard anyway.

Cc: Haavard Skinnemoen <hskinnemoen@gmail.com>
Cc: Rafał Miłecki <zajec5@gmail.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Cc: Alek Du <alek.du@intel.com>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.com>
Acked-by: NDmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: NLee Jones <lee.jones@linaro.org>
Acked-by: NJiri Kosina <jkosina@suse.cz>
Acked-by: NHans-Christian Egtvedt <egtvedt@samfundet.no>
Acked-by: NJacek Anaszewski <j.anaszewski@samsung.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

The spinlock 'slock' is used now to protect pcf857x_irq() from itself
which is unnecessary (especially after switching to use threaded
IRQs). Hence, remove it and use mutex to protect device data in IRQ
handler.

Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NGrygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Now pcf857x_irq() IRQ's dispatcher will try to run nested
IRQ handlers for each GPIO pin which state has changed.
Such IRQs are, actually, spurious and nested IRQ handlers
have to be called only for IRQs wich were enabled by users.
This is not critical issue - just  /proc/interrupts
will display counters for unused IRQS:
399:          4          0   pcf857x   0 Edge
428:          1          0   pcf857x  13 Edge
430:          1          0   pcf857x  15 Edge

Hence, fix it by adding irq_enabled field in struct pcf857x to track
enabled GPIO IRQs and corresponding callbacks in pcf857x_irq_chip.

Similar functionality was presented in pcf857x driver, commit
21fd3cd1 ('gpio: pcf857x: call the gpio user handler iff...')

and then it was removed by commit
 a39294bd ('gpio: pcf857x: Switch to use gpiolib irqchip...')

Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Fixes: a39294bd ('gpio: pcf857x: Switch to use gpiolib irqchip helpers')
Signed-off-by: NGrygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

If an interrupt controller doesn't support wake-up configuration,
irq_set_irq_wake() returns an error code.  Then any subsequent call
trying to deconfigure wake-up will cause an imbalance, and a warning
will be printed:

    WARNING: CPU: 1 PID: 1341 at kernel/irq/manage.c:540 irq_set_irq_wake+0x
    Unbalanced IRQ 26 wake disable

To fix this, refrain from any further parent interrupt controller
(de)configuration if irq_set_irq_wake() failed.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

The pcf857x GPIO and interrupt controller uses dummy_irq_chip, which
does not implement irq_chip.irq_set_wake() and does not set
IRQCHIP_SKIP_SET_WAKE.

This causes two s2ram issues if wake-up is enabled for the pcf857x GPIO
pins:
  1. During resume from s2ram, the following warning is printed:

     WARNING: CPU: 0 PID: 1046 at kernel/irq/manage.c:537 irq_set_irq_wake+0x9c/0xf8()
     Unbalanced IRQ 113 wake disable

  2. Wake-up through the pcf857x GPIO pins may fail, as the parent
     interrupt controller may be suspended.

Migrate the pcf857x GPIO and interrupt controller from dummy_irq_chip to
its own irq_chip. This irq chip implements irq_chip.irq_set_wake() to
propagate its wake-up setting to the parent interrupt controller.

This fixes wake-up through gpio-keys on sh73a0/kzm9g, where the pcf857x
interrupt is cascaded to irq-renesas-intc-irqpin, and the latter must
not be suspended when wake-up is enabled.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Switch the PCF857x GPIO driver to use the gpiolib irqchip helpers.
This driver uses a nested threaded interrupt, hence handle_nested_irq()
and gpiochip_set_chained_irqchip() must be used.

Note that this removes the checks added in commit 21fd3cd1
("gpio: pcf857x: call the gpio user handler iff gpio_to_irq is done"),
as the interrupt mappings are no longer created on-demand by the driver,
but by gpiochip_irqchip_add() during initialization.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Signed-off-by: Nabdoulaye berthe <berthe.ab@gmail.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

It's quite possible that multiple pcf857x can be hooked up
to the same interrupt line with the processor. So add IRQF_SHARED
in request irq..
Signed-off-by: NGeorge Cherian <george.cherian@ti.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Currently irq_domain_cleanup is called twice if irq_domain_init fails.
This causes the following crash.

Unable to handle kernel paging request at virtual address 00100104
pgd = c0004000
[00100104] *pgd=00000000
Internal error: Oops: 805 [#1] SMP ARM
Modules linked in:
CPU: 0 PID: 6 Comm: kworker/u4:0 Not tainted 3.12.15-01889-gedd10a8-dirty #4
Workqueue: deferwq deferred_probe_work_func
task: ed0ee800 ti: ed116000 task.ti: ed116000
PC is at irq_domain_remove+0x3c/0x8c
LR is at 0x0
pc : [<c0089734>]    lr : [<00000000>]    psr: a0000013
sp : ed117b50  ip : 00100100  fp : ed117b64
r10: ed5d1a04  r9 : 00000008  r8 : 00000000
r7 : ffffffea  r6 : ed5d1a20  r5 : ed5d1a00  r4 : ed5e7540
r3 : 00200200  r2 : 00100100  r1 : c08aa180  r0 : 00200200
Flags: NzCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment kernel
Control: 10c53c7d  Table: 8000406a  DAC: 00000017
Process kworker/u4:0 (pid: 6, stack limit = 0xed116248)
Stack: (0xed117b50 to 0xed118000)
7b40:                                     0000016b ed5d5f10 ed117b74 ed117b68
7b60: c02c8910 c0089704 ed117bb4 ed117b78 c02c8e14 c02c8900 ed5d1a04 ed5d4e80
...
<snip>
...
fe0: 00000000 00000000 00000000 00000000 00000013 00000000 384a13ea 1590210a
Backtrace:
[<c00896f8>] (irq_domain_remove+0x0/0x8c) from [<c02c8910>] (pcf857x_irq_domain_cleanup+0x1c/0x20)
 r4:ed5d5f10 r3:0000016b
[<c02c88f4>] (pcf857x_irq_domain_cleanup+0x0/0x20) from [<c02c8e14>] (pcf857x_probe+0x2a8/0x364)
[<c02c8b6c>] (pcf857x_probe+0x0/0x364) from [<c04787ac>] (i2c_device_probe+0x80/0xc0)
[<c047872c>] (i2c_device_probe+0x0/0xc0) from [<c036c33c>] (driver_probe_device+0x104/0x240)
 r6:00000000 r5:ed5d1a20 r4:c08c709c r3:c047872c
[<c036c238>] (driver_probe_device+0x0/0x240) from [<c036c558>] (__device_attach+0x48/0x4c)
 r7:ed4fc480 r6:c036c510 r5:ed5d1a20 r4:c0866bb8
[<c036c510>] (__device_attach+0x0/0x4c) from [<c036a6d8>] (bus_for_each_drv+0x4c/0x94)
 r5:ed5d1a20 r4:00000000
[<c036a68c>] (bus_for_each_drv+0x0/0x94) from [<c036c1f4>] (device_attach+0x78/0x90)
 r6:c087fe50 r5:ed5d1a54 r4:ed5d1a20
[<c036c17c>] (device_attach+0x0/0x90) from [<c036b76c>] (bus_probe_device+0x8c/0xb4)
 r6:c087fe50 r5:ed5d1a20 r4:ed5d1a20 r3:ed17e1c0
[<c036b6e0>] (bus_probe_device+0x0/0xb4) from [<c0369888>] (device_add+0x34c/0x624)
 r6:ed5d1a28 r5:00000000 r4:ed5d1a20 r3:fffffffe
[<c036953c>] (device_add+0x0/0x624) from [<c0369b7c>] (device_register+0x1c/0x20)
...
<snip>
...
[<c0060844>] (process_one_work+0x0/0x37c) from [<c0061040>] (worker_thread+0x13c/0x3c4)
[<c0060f04>] (worker_thread+0x0/0x3c4) from [<c00670ec>] (kthread+0xac/0xb8)
[<c0067040>] (kthread+0x0/0xb8) from [<c00148b8>] (ret_from_fork+0x14/0x3c)
 r7:00000000 r6:00000000 r5:c0067040 r4:ed105d20
Code: e59fc04c e591e000 e59f0048 e154000e (e5823004)
---[ end trace 59dd1e90032c4217 ]---
Signed-off-by: NGeorge Cherian <george.cherian@ti.com>
Reviewed-by: NAlexandre Courbot <acourbot@nvidia.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

This switches the two members of struct gpio_chip that were
defined as unsigned foo:1 to bool, because that is indeed what
they are. Switch all users in the gpio and pinctrl subsystems
to assign these values with true/false instead of 0/1. The
users outside these subsystems will survive since true/false
is 1/0, atleast we set some kind of more strict typing example.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Add DT bindings for the pcf857x-compatible chips and parse the device
tree node in the driver.
Signed-off-by: NLaurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

As per the pattern from other GPIO drivers, use set_irq_flags()
on ARM only, use irq_set_noprobe() on other archs.

Also rename the argument "virq" to just "irq", this IRQ isn't
any more "virtual" than any other Linux IRQ number, we use
"hwirq" for the actual hw-numbers, "virq" is just bogus.

Cc: George Cherian <george.cherian@ti.com>
Cc: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Reviewed-by: NFelipe Balbi <balbi@ti.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

For pcf857x driver if the initial state is not set properly (proper
n_latch is not passed), we get bad irq prints on console.
We get this only for the first interrupt and doesnot repeat for further
interrupts unles and until there are other gpio pins which are not flipping
continously.

following prints are seen on console.

[   40.983924] irq 0, desc: ce004080, depth: 1, count: 0, unhandled: 0
[   40.990511] ->handle_irq():  c00aa538, handle_bad_irq+0x0/0x260
[   40.996768] ->irq_data.chip(): c080b6ec, no_irq_chip+0x0/0x60
[   41.002842] ->action():   (null)
[   41.006242]    IRQ_NOPROBE set
[   41.009465]  IRQ_NOREQUEST set
Signed-off-by: NGeorge Cherian <george.cherian@ti.com>
Acked-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Now that we are using devm_request_threaded_irq no need for
irq_demux_work and gpio->irq. Remove all its references.
Signed-off-by: NGeorge Cherian <george.cherian@ti.com>
Acked-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Remove the request_irq and use devm_request_threaded_irq
also cleanup free_irq. devm_* takes care of that.
Signed-off-by: NGeorge Cherian <george.cherian@ti.com>
Acked-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

The argument is not used, remove it. No board registers a pcf857x device
with an IRQ without specifying platform data, IRQ domain registration
behaviour is thus not affected by this change.
Signed-off-by: NLaurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

This makes checking for duplicates when adding a new #include easier.
Signed-off-by: NLaurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Use the wrapper function for retrieving the platform data instead of
accessing dev->platform_data directly.
Signed-off-by: NJingoo Han <jg1.han@samsung.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Use devm_kzalloc() to make cleanup paths simpler.
Signed-off-by: NJingoo Han <jg1.han@samsung.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Signed-off-by: NNikolay Balandin <nbalandin@dev.rtsoft.ru>
Acked-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

6e20a0a4
(gpio: pcf857x: enable gpio_to_irq() support)
added gpio_to_irq() support on pcf857x driver,
but it used pdata->irq.
This patch modifies driver to use client->irq instead of it.
It modifies kzm9g board platform settings,
and device probe information too.
This patch is tested on kzm9g board
Reported-by: NChristian Engelmayer <christian.engelmayer@frequentis.com>
Acked-by: NSimon Horman <horms+renesas@verge.net.au>
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

6e20a0a4
(gpio: pcf857x: enable gpio_to_irq() support)
added new smatch warnings

drivers/gpio/gpio-pcf857x.c:288 pcf857x_probe() error: we previously \
	assumed 'pdata' could be null (see line 277)
drivers/gpio/gpio-pcf857x.c:364 pcf857x_probe() warn: variable dereferenced\
	 before check 'pdata' (see line 292)
drivers/gpio/gpio-pcf857x.c:421 pcf857x_remove() error: we previously\
	 assumed 'pdata' could be null (see line 410)

This patch fixes it
Reported-by: NFengguang Wu <fengguang.wu@intel.com>
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

pcf857x chip has some pins, but interrupt pin is only 1 pin.
And gpiolib requests 1 interrupt per 1 gpio pin.

Thus, this patch added demuxed irq to pcf857x driver,
and enabled gpio_to_irq().
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

This patch adds 8/16 bit write/read functions,
and shared gpio input/output/set/get functions.
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

This patch adds a kernel message, containing GPIO range and device
name on successful device registration, and removes duplicate messages from the following drivers:
	* gpio-adp5588
	* gpio-bt8xx
	* gpio-cs5535
	* gpio-janz-ttl
	* gpio-nomadik
	* gpio-pcf857x
	* gpio-xilinx
	* drivers/of/gpio.c
Signed-off-by: NHartmut Knaack <knaack.h@gmx.de>
[grant.likely@secretlab.ca: squashed 2 patches together]
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>

A pending cleanup will mean that module.h won't be implicitly
everywhere anymore.  Make sure the modular drivers in gpio
are actually calling out for <module.h> explicitly in advance.
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

Sort the gpio makefile and enforce the naming convention gpio-*.c for
gpio drivers.

v2: cleaned up filenames in Kconfig and comment blocks
v3: fixup use of BASIC_MMIO to GENERIC_GPIO for mxc
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>

Provide sane defaults for pcf857x, so the driver can be used w/o providing
platform data (and thus can be simply bound via OF tree).
Signed-off-by: NDmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: David Brownell <david-b@pacbell.net>
Cc: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Drivers should be including <linux/gpio.h> not <asm/gpio.h>.
Signed-off-by: NH Hartley Sweeten <hsweeten@visionengravers.com>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The deprecated pcf8574 driver is going to be removed. Make sure the
replacement driver inherits all i2c_device_ids for a smooth transition.
Signed-off-by: NWolfram Sang <w.sang@pengutronix.de>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: NJean Delvare <khali@linux-fr.org>

A number of drivers in drivers/gpio return -ENODEV when confronted with
missing setup parameters such as the platform data.  However, returning
-ENODEV causes the driver layer to silently ignore the driver as it
assumes the probe did not find anything and was only speculative.

To make life easier to discern why a driver is not being attached, change
to returning -EINVAL, which is a better description of the fact that the
driver data was not valid.

Also add a set of dev_dbg() statements to the error paths to provide an
better explanation of the error as there may be more that one point in the
driver.
Signed-off-by: NBen Dooks <ben-linux@fluff.org>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>