mmc: slot-gpio: Allow non-sleeping GPIO ro

This change uses the appropriate _cansleep or non-sleeping API for
reading GPIO read-only state. This allows users with GPIOs that
never sleepbeing called in atomic context.

Implement the same mechanism as in commit 52af318c93e97 ("mmc: Allow
non-sleeping GPIO cd").

Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240206083912.2543142-1-alexander.stein@ew.tq-group.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

mmc: core: support setting card detect interrupt from drivers

On certain platforms like Amlogic Meson gpiod_to_irq() isn't supported
due to the design of gpio / interrupt controller. Therefore provide an
option for drivers to pass the card detect interrupt number
(retrieved e.g. from device tree) to mmc core.

Suggested-by refers to the mechanism to pass and store the interrupt.

Suggested-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Link: https://lore.kernel.org/r/5777f38b-465f-ce48-a87f-5eb8b3c57b0a@gmail.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

mmc: slot-gpio: Update default label when no con_id provided

Currently default label of GPIO is assigned to the device name,
when no con_id provided. Instead, let's update it to reflect
what it's about (use already prepared template).

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210929111757.52625-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

mmc: slot-gpio: Refactor mmc_gpio_alloc()

Refactor mmc_gpio_alloc() to drop unneeded indentation level
and double condition. This increases readability of the code.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210929111757.52625-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

mmc: core: Remove mmc_gpiod_request_*(invert_gpio)

Now that invert_gpio arguments are unused, let's remove them.

Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Link: https://lore.kernel.org/r/64d766d1f8af2e22bce32f4ffa453f7234207ad6.1576031637.git.mirq-linux@rere.qmqm.pl
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

mmc: core: Rework cd-gpio handling

There are a few places around the code that invert inverted and possibly
inverted CD line. That's really confusing. Squash them all into one place
in mmc_gpiod_request_cd(). MMC_CAP2_CD_ACTIVE_HIGH is used analogously to
WP line: in GPIO mode it is used only at probe time to switch polarity, for
native mode it is left as is.

Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Link: https://lore.kernel.org/r/db189b715596d63caf8c6a088bddc71dd69a879b.1576031637.git.mirq-linux@rere.qmqm.pl
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

mmc: core: Rework wp-gpio handling

Use MMC_CAP2_RO_ACTIVE_HIGH flag as indicator if GPIO line is to be
inverted compared to DT/platform-specified polarity. The flag is not used
after init in GPIO mode anyway. No functional changes intended.

Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Link: https://lore.kernel.org/r/a60f563f11bbff821da2fa2949ca82922b144860.1576031637.git.mirq-linux@rere.qmqm.pl
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

Based on 2 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation #

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

mmc: slot-gpio: Remove override_active_level on WP

The argument "override_active_level" made it possible to
enforce a specific polarity on the write-protect
GPIO line. All callers in the kernel pass "false" to this
call after I have converted all drivers to use GPIO machine
descriptors, so remove the argument and clean out this.

This kind of polarity inversion should be handled by the
GPIO descriptor inside the GPIO library if needed.

This rids us of one instance of the kludgy calls into
the gpiod_get_raw_value() API.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

mmc: slot-gpio: Delete legacy GPIO handling

All host drivers are converted to look up GPIO descriptors
from device tree, ACPI or machine descriptor tables, so now
we can delete the legacy GPIO handling using hardcoded GPIO
numbers from the kernel.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

mmc: slot-gpio: Allocate GPIO labels dynamically

The use of string pointers in the MMC slot GPIO context is
pretty dubious, allocating some 2*len extra bytes for each
label of the ro and wp pins.

Tidy this up using kasprintf() with dynamic allocation of
labels for these strings.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

mmc: slot-gpio: Fix debounce time to use miliseconds again

The debounce value passed to mmc_gpiod_request_cd() function is in
microseconds, but msecs_to_jiffies() requires the value to be in
miliseconds to properly calculate the delay, so adjust the value stored
in cd_debounce_delay_ms context entry.

Fixes: 1d71926bbd59 ("mmc: core: Fix debounce time to use microseconds")
Fixes: bfd694d5e21c ("mmc: core: Add tunable delay before detecting card
after card is inserted")
Cc: stable@vger.kernel.org # v4.18+
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

mmc: core: cd_label must be last entry of mmc_gpio struct

commit bfd694d5e21c ("mmc: core: Add tunable delay
before detecting card after card is inserted") adds
"u32 cd_debounce_delay_ms" to the last of mmc_gpio
struct and cause "char cd_label[0]" NOT work as string
pointer of card detect label, when "cat /proc/interrupts",
the devname for card detect gpio is incorrect as below:

144: 0 gpio-mxc 22 Edge ▒
161: 0 gpio-mxc 7 Edge ▒

Move the cd_label field down to fix this, and drop the
zero from the array size to prevent future similar bugs,
the result is correct as below:

144: 0 gpio-mxc 22 Edge 2198000.mmc cd
161: 0 gpio-mxc 7 Edge 2190000.mmc cd

Fixes: bfd694d5e21c ("mmc: core: Add tunable delay before detecting card after card is inserted")
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Tested-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

mmc: Allow non-sleeping GPIO cd

This change uses the appropriate _cansleep or non-sleeping API for
reading GPIO card detect state. This allows users with GPIOs that
never sleep to avoid a warning when certain quirks are present.

The sdhci controller has an SDHCI_QUIRK_NO_CARD_NO_RESET, which
indicates that a controller will not reset properly if no card is
inserted. With this quirk enabled, mmc_get_cd_gpio is called in
several places with a spinlock held and interrupts disabled.
gpiod_get_raw_value_cansleep is not happy with this situation,
and throws out a warning.

For boards that a) use controllers that have this quirk, and b) wire
card detect up to a GPIO that doesn't sleep, this is a spurious warning.
This change silences that warning, at the cost of pushing this problem
down to users that have sleeping GPIOs and controllers with this quirk.

Signed-off-by: Evan Green <evgreen@chromium.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

mmc: core: Add tunable delay before detecting card after card is inserted

Allow to use tunable delay before detecting card after card is inserted,
which either comes from firmware node, or comes from debounce value
passed on to mmc_gpiod_request_cd(). If the platform doesn't support
debounce, then we fall back to use the debounce period as the delay,
otherwise, it behaves the same as before that a HW debounce(if set) plus
a 200ms hardcode delay before detecting the card.

Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

mmc: sdhci-pci: Respect PM flags when enabling card detect GPIO IRQ wakeup

Commit 03dbaa04a2e5 ("mmc: slot-gpio: Add support to enable irq wake on
cd_irq") enabled wakeup at initialization. However, users also want to
control it from sysfs power/wakeup attribute. That means the driver needs
to check the PM flags before enabling it in the suspend callback. Add
support for that in sdhci-pci, which is the only driver presently using the
MMC_CAP_CD_WAKE flag, and remove the enabling in mmc_gpiod_request_cd_irq()

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

mmc: slot-gpio: Add a function to enable/disable card detect IRQ wakeup

Commit 03dbaa04a2e5 ("mmc: slot-gpio: Add support to enable irq wake on
cd_irq") enabled wakeup at initialization. However drivers may wish to
enable and disable based on different criteria. Add a helper function
mmc_gpio_set_cd_wake() to make it easy for drivers to do that.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

mmc: slot-gpio: add a helper to check capability of GPIO WP detection

Like mmc_can_gpio_cd(), mmc_can_gpio_ro() will also be useful for host
drivers to know whether GPIO write-protect detection is supported.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

mmc: slot-gpio: call gpiod_to_irq() only when MMC_CAP_NEEDS_POLL is unset

It is not efficient to call gpiod_to_irq() regardless the flag, then
ignore the returned irq if MMC_CAP_NEEDS_POLL.

Move gpiod_to_irq() after the MMC_CAP_NEEDS_POLL check.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

mmc: slot-gpio: Add support to enable irq wake on cd_irq

Add host capability MMC_CAP_CD_WAKE to enable irq wake on the card detect
irq.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

mmc: slot-gpio: Don't override con_id when request descriptor

The caller may supply connection ID, index, or both. All combinations are
possible and mmc framework should not make any assumption on what exactly
caller wants.

Remove con_id override conditionals in mmc_gpiod_request_ro() and
mmc_gpiod_request_cd().

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

mmc: core: expose the capability of gpio card detect

Add new helper API mmc_can_gpio_cd for slot-gpio to make
host drivers know whether it supports gpio card detect.

Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

mmc: slot-gpio: Allow host driver to provide isr for card-detect interrupts

One of the reasons omap_hsmmc doesn't use the slot-gpio library
is that it has some non-standard functionality in the card-detect
interrupt service routine.

To make it possible for omap_hsmmc (and maybe others) to be converted
to use slot-gpio, add 'mmc_gpio_request_cd_isr' which provide an
alternate isr to be register by the slot-gpio code.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

mmc: slot-gpio: Rework how to handle allocation of slot-gpio data

By moving the allocation of the slot-gpio data into mmc_alloc_host(),
we can remove the slot-gpio internal calls to mmc_gpio_alloc().

This means mmc_gpio_alloc() has now only one caller left, which
consequence allow us to simplify and remove some of the slot-gpio code.

Additionally, this makes the slot-gpio mutex redundant, so let's remove
it.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

mmc: slot-gpio: Make mmc_gpio_alloc() available for MMC core

As a step in moving slot-gpio functions/structs closer to the MMC core,
let's add a local header file for slot-gpio.

In this initial step we move mmc_gpio_alloc() into the header file,
to make it available for the MMC core. Following patches will show the
utilization of it.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

mmc: slot-gpio: Use the parent device while allocating data

We had a mix of using the class device and the parent device while
allocating data through the devm_* managed functions.

Let's be more consistent and always use the parent device.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

mmc: slot-gpio: Remove option to explicitly free requested CD/WP GPIOs

The slot-gpio uses the devm*_ managed functions. Still it provide APIs
to explicitly free requested CD/WP GPIOs, but these API isn't being
used.

Therefore let's simplify slot-gpio by removing these unused APIs. If it
later turns out we need some of them, we can always consider to restore
the code.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

mmc: core: restore detect line inversion semantics

commit 98e90de99a0c43bd434da814c882c4332441871e
"mmc: host: switch OF parser to use gpio descriptors"
switched the semantic behaviour of card detect and read
only flags such that the inversion capability flag would
only be set if inversion was explicitly specified in the
device tree, in the hopes that no-one was using double
inversion.

It turns out that the XOR:ing between the explicit
inversion was indeed in use, so we need to restore the
old semantics where both ways of inversion are checked
and the end result XOR:ed.

Reported-by: Javier Martinez Canillas <javier@dowhile0.org>
Tested-by: Javier Martinez Canillas <javier@dowhile0.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

mmc: Fix use of wrong device in mmc_gpiod_free_cd()

mmc_gpiod_free_cd() is paired with mmc_gpiod_request_cd()
and both must reference the same device which is the
actual host controller device not the mmc_host class
device.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

mmc: don't request CD IRQ until mmc_start_host()

As soon as the CD IRQ is requested, it can trigger, since it's an
externally controlled event. If it does, delayed_work host->detect will
be scheduled.

Many host controller probe()s are roughly structured as:

*_probe() {
host = sdhci_pltfm_init();
mmc_of_parse(host->mmc);
rc = sdhci_add_host(host);
if (rc) {
sdhci_pltfm_free();
return rc;
}

In 3.17, CD IRQs can are enabled quite early via *_probe() ->
mmc_of_parse() -> mmc_gpio_request_cd() -> mmc_gpiod_request_cd_irq().

Note that in linux-next, mmc_of_parse() calls mmc_gpio*d*_request_cd()
rather than mmc_gpio_request_cd(), and mmc_gpio*d*_request_cd() doesn't
call mmc_gpiod_request_cd_irq(). However, this issue still exists if
mmc_gpio_request_cd() is called directly before mmc_start_host().

sdhci_add_host() may fail part way through (e.g. due to deferred
probe for a vmmc regulator), and sdhci_pltfm_free() does nothing to
unrequest the CD IRQ nor cancel the delayed_work. sdhci_pltfm_free() is
coded to assume that if sdhci_add_host() failed, then the delayed_work
cannot (or should not) have been triggered.

This can lead to the following with CONFIG_DEBUG_OBJECTS_* enabled, when
kfree(host) is eventually called inside sdhci_pltfm_free():

WARNING: CPU: 2 PID: 6 at lib/debugobjects.c:263 debug_print_object+0x8c/0xb4()
ODEBUG: free active (active state 0) object type: timer_list hint: delayed_work_timer_fn+0x0/0x18

The object being complained about is host->detect.

There's no need to request the CD IRQ so early; mmc_start_host() already
requests it. For most SDHCI hosts at least, the typical call path that
does this is: *_probe() -> sdhci_add_host() -> mmc_add_host() ->
mmc_start_host(). Therefore, remove the call to mmc_gpiod_request_cd_irq()
from mmc_gpio_request_cd(). This also matches mmc_gpio*d*_request_cd(),
which already doesn't call mmc_gpiod_request_cd_irq().

However, some host controller drivers call mmc_gpio_request_cd() after
mmc_start_host() has already been called, and assume that this will also
call mmc_gpiod_request_cd_irq(). Update those drivers to explicitly call
mmc_gpiod_request_cd_irq() themselves. Ideally, these drivers should be
modified to move their call to mmc_gpio_request_cd() before their call
to mmc_add_host(). However that's too large a change for stable.

This solves the problem (eliminates the kernel error message above),
since it guarantees that the IRQ can't trigger before mmc_start_host()
is called.

The critical point here is that once sdhci_add_host() calls
mmc_add_host() -> mmc_start_host(), sdhci_add_host() is coded not to
fail. In other words, if there's a chance that mmc_start_host() may have
been called, and CD IRQs triggered, and the delayed_work scheduled,
sdhci_add_host() won't fail, and so cleanup is no longer via
sdhci_pltfm_free() (which doesn't free the IRQ or cancel the work queue)
but instead must be via sdhci_remove_host(), which calls mmc_remove_host()
-> mmc_stop_host(), which does free the IRQ and cancel the work queue.

CC: Russell King <linux@arm.linux.org.uk>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexandre Courbot <acourbot@nvidia.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: <stable@vger.kernel.org> # v3.15+
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

mmc: slot-gpio: add gpiod variant to get wp GPIO

This makes it possible to get the write protect (read only)
GPIO line from a GPIO descriptor. Written to exactly mirror
the card detect function.

Acked-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

mmc: slot-gpio: switch to use flags when getting GPIO

When the slot GPIO driver gets the GPIO to be used for card
detect, it is now possible to specify a flag to have the line
set up as input. Get rid of the explicit setup call for input
and use the flag.

The extra argument works as there are transition varargs
macros in place in the <linux/gpio/consumer.h> header, in
the future we will make the flags argument compulsory.

Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

mmc: Delay the card_event callback into the mmc_rescan worker

This change removes the callback from atomic context which it doesn't
need to be in, and puts it in line with the debounced rescan.

This code is based on these e-mail threads with Christian Daudt:

https://lkml.org/lkml/2013/8/19/539
https://lkml.org/lkml/2014/3/19/79

Signed-off-by: Markus Mayer <markus.mayer@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Chris Ball <chris@printf.net>

mmc: slot-gpio: Add GPIO descriptor based CD GPIO API

Add functions to request a CD GPIO using the GPIO descriptor API.
Note that the new request function is paired with mmc_gpiod_free_cd()
not mmc_gpio_free_cd(). Note also that it must be called prior to
mmc_add_host() otherwise the caller must also call
mmc_gpiod_request_cd_irq().

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Chris Ball <chris@printf.net>

mmc: slot-gpio: Split out CD IRQ request into a separate function

In preparation for adding a descriptor-based CD GPIO API, split out
CD IRQ request into a separate function.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Chris Ball <chris@printf.net>

mmc: slot-gpio: Record GPIO descriptors instead of GPIO numbers

In preparation for adding a descriptor-based CD GPIO API, switch from
recording GPIO numbers to recording GPIO descriptors.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Tested-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Chris Ball <chris@printf.net>

mmc: slot-gpio: Add debouncing capability to mmc_gpio_request_cd()

Add a debounce parameter to the mmc_gpio_request_cd() function that
enables GPIO debouncing when set to a non-zero value. This can be used
by MMC host drivers to enable debouncing on the card detect signal.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Chris Ball <cjb@laptop.org>

mmc: slot-gpio: use devm_* managed functions to ease users

Use devm_* managed functions, so that slot-gpio users do not have to
call mmc_gpio_free_ro/cd to free up resources requested in
mmc_gpio_request_ro/cd.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Acked-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Chris Ball <cjb@laptop.org>

mmc: slot-gpio: use devm_* managed functions to ease users

Use devm_* managed functions, so that slot-gpio users do not have to
call mmc_gpio_free_ro/cd to free up resources requested in
mmc_gpio_request_ro/cd.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Acked-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Chris Ball <cjb@laptop.org>

mmc: extend the slot-gpio card-detection to use host's .card_event() method

The slot-gpio API provides a generic card-detection handler. To support a
wider range of hosts it has to call the host's card-event callback, if
implemented. Also increase the debounce interval to 200ms to match the
SDHCI driver.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Reviewed-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Chris Ball <cjb@laptop.org>

mmc: slot-gpio: Fix missing assignment to ctx->ro_gpio

mmc_gpio_request_ro() doesn't store the requested gpio in ctx->ro_gpio.
As a result, subsequent calls to mmc_gpio_get_ro() will always fail
with -ENOSYS because the gpio number isn't available to that function.

Cc: stable <stable@vger.kernel.org>
Acked-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Chris Ball <cjb@laptop.org>

mmc: core: add WP pin handler to slot functions

Card Write-Protect pin is often implemented, using a GPIO, which makes
it simple to provide a generic handler for it.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Chris Ball <cjb@laptop.org>

mmc: core: convert slot functions to managed allocation

This prepares for the addition of further slot functions.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Chris Ball <cjb@laptop.org>

mmc: add CD GPIO polling support to slot functions

A simple extension of mmc slot functions add support for CD GPIO polling
for cases where the GPIO cannot produce interrupts, or where this is not
desired for some reason.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Chris Ball <cjb@laptop.org>

mmc: core: use a more generic name for slot function types and fields

struct mmc_host::hotplug is becoming a generic hook for slot functions.
Rename it accordingly.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Chris Ball <cjb@laptop.org>

mmc: extend and rename cd-gpio helpers to handle more slot GPIO functions

GPIOs can be used in MMC/SD-card slots not only for hotplug detection, but
also to implement the write-protection pin. Rename cd-gpio helpers to
slot-gpio to make addition of further slot GPIO functions possible.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Chris Ball <cjb@laptop.org>