linux-toradex.git/drivers/mmc/core/pwrseq_simple.c, branch v5.0

mmc: pwrseq_simple: Fix incorrect handling of GPIO bitmap

2018-10-15T14:26:00+00:00

Commit b9762bebc633 ("gpiolib: Pass bitmaps, not integer arrays, to
get/set array") changed the way GPIO values are passed to
gpiod_get/set_array_value() and friends.  The new code introduced into
mmc_pwrseq_simple_set_gpios_value() incorrectly interpretes the 'value'
argument as a bitmap of GPIO values and assigns it directly to the
'values' bitmap variable passed to gpiod_set_array_value_cansleep()
instead of filling that bitmap with bits equal to the 'value' argument.
As a result, only member 0 of the array is handled correctly.

Moreover, wrong assumption is taken about the 'values' bitmap size not
exceding the number of bits of the 'value' argument type.

Fix it.

Signed-off-by: Janusz Krzysztofik 
Tested-by: Marek Szyprowski 
Acked-by: Ulf Hansson 
Signed-off-by: Linus Walleij

gpiolib: Pass array info to get/set array functions

2018-09-13T09:16:54+00:00

In order to make use of array info obtained from gpiod_get_array() and
speed up processing of arrays matching single GPIO chip layout, that
information must be passed to get/set array functions.  Extend the
functions' API with that additional parameter and update all users.
Pass NULL if a user builds an array itself from single GPIOs.

Cc: Jonathan Corbet 
Cc: Miguel Ojeda Sandonis 
Cc: Geert Uytterhoeven 
Cc: Sebastien Bourdelin 
Cc: Lukas Wunner 
Cc: Peter Korsgaard 
Cc: Peter Rosin 
Cc: Andrew Lunn 
Cc: Florian Fainelli 
Cc: "David S. Miller" 
Cc: Rojhalat Ibrahim 
Cc: Dominik Brodowski 
Cc: Russell King 
Cc: Kishon Vijay Abraham I 
Cc: Tony Lindgren 
Cc: Lars-Peter Clausen 
Cc: Michael Hennerich 
Cc: Jonathan Cameron 
Cc: Hartmut Knaack 
Cc: Peter Meerwald-Stadler 
Cc: Greg Kroah-Hartman 
Cc: Jiri Slaby 
Cc: Yegor Yefremov 
Cc: Uwe Kleine-König 
Signed-off-by: Janusz Krzysztofik 
Acked-by: Ulf Hansson 
Signed-off-by: Linus Walleij

gpiolib: Pass bitmaps, not integer arrays, to get/set array

2018-09-13T09:15:30+00:00

Most users of get/set array functions iterate consecutive bits of data,
usually a single integer, while processing array of results obtained
from, or building an array of values to be passed to those functions.
Save time wasted on those iterations by changing the functions' API to
accept bitmaps.

All current users are updated as well.

More benefits from the change are expected as soon as planned support
for accepting/passing those bitmaps directly from/to respective GPIO
chip callbacks if applicable is implemented.

Cc: Jonathan Corbet 
Cc: Miguel Ojeda Sandonis 
Cc: Sebastien Bourdelin 
Cc: Lukas Wunner 
Cc: Peter Korsgaard 
Cc: Peter Rosin 
Cc: Andrew Lunn 
Cc: Florian Fainelli 
Cc: "David S. Miller" 
Cc: Rojhalat Ibrahim 
Cc: Dominik Brodowski 
Cc: Russell King 
Cc: Kishon Vijay Abraham I 
Cc: Tony Lindgren 
Cc: Lars-Peter Clausen 
Cc: Michael Hennerich 
Cc: Jonathan Cameron 
Cc: Hartmut Knaack 
Cc: Peter Meerwald-Stadler 
Cc: Greg Kroah-Hartman 
Cc: Jiri Slaby 
Cc: Yegor Yefremov 
Cc: Uwe Kleine-König 
Signed-off-by: Janusz Krzysztofik 
Acked-by: Ulf Hansson 
Reviewed-by: Geert Uytterhoeven 
Tested-by: Geert Uytterhoeven 
Signed-off-by: Linus Walleij

mmc: pwrseq: Use kmalloc_array instead of stack VLA

2018-05-02T13:08:29+00:00

The use of stack Variable Length Arrays needs to be avoided, as they
can be a vector for stack exhaustion, which can be both a runtime bug
(kernel Oops) or a security flaw (overwriting memory beyond the
stack). Also, in general, as code evolves it is easy to lose track of
how big a VLA can get. Thus, we can end up having runtime failures
that are hard to debug. As part of the directive[1] to remove all VLAs
from the kernel, and build with -Wvla.

Currently driver is using a VLA declared using the number of descriptors.  This
array is used to store integer values and is later used as an argument to
`gpiod_set_array_value_cansleep()` This can be avoided by using
`kmalloc_array()` to allocate memory for the array of integer values.  Memory is
free'd before return from function.

>From the code it appears that it is safe to sleep so we can use GFP_KERNEL
(based _cansleep() suffix of function `gpiod_set_array_value_cansleep()`.

It can be expected that this patch will result in a small increase in overhead
due to the use of `kmalloc_array()`

[1] https://lkml.org/lkml/2018/3/7/621

Signed-off-by: Tobin C. Harding 
Signed-off-by: Ulf Hansson

mmc: pwrseq_simple: Parse DTS for the power-off-delay-us property

2017-05-23T12:17:36+00:00

If the optional power-off-delay-us property is found, insert the
corresponding delay after asserting the GPIO during power off. This enables
a graceful shutdown sequence for some devices.

Cc: linux-mmc@vger.kernel.org
Signed-off-by: Ulf Hansson 
Acked-by: Arnd Bergmann

mmc: pwrseq-simple: Add an optional post-power-on-delay

2016-09-26T19:31:07+00:00

Some devices need a while to boot their firmware after providing clks /
de-asserting resets before they are ready to receive sdio commands.

This commits adds a post-power-on-delay-ms devicetree property to
mmc-pwrseq-simple for use with such devices.

Signed-off-by: Hans de Goede 
Acked-by: Rob Herring 
Signed-off-by: Ulf Hansson

mmc: pwrseq: convert to proper platform device

2016-05-02T08:33:30+00:00

simple-pwrseq and emmc-pwrseq drivers rely on platform_device
structure from of_find_device_by_node(), this works mostly. But, as there
is no driver associated with this devices, cases like default/init pinctrl
setup would never be performed by pwrseq. This becomes problem when the
gpios used in pwrseq require pinctrl setup.

Currently most of the common pinctrl setup is done in
drivers/base/pinctrl.c by pinctrl_bind_pins().

There are two ways to solve this issue on either convert pwrseq drivers
to a proper platform drivers or copy the exact code from
pcintrl_bind_pins(). I prefer converting pwrseq to proper drivers so that
other cases like setting up clks/parents from dt would also be possible.

Signed-off-by: Srinivas Kandagatla 
Signed-off-by: Ulf Hansson

mmc: pwrseq_simple: add to_pwrseq_simple() macro

2016-05-02T08:33:30+00:00

This patch adds to_pwrseq_simple() macro to make the code more readable.

Signed-off-by: Srinivas Kandagatla 
Signed-off-by: Ulf Hansson

mmc: core: pwrseq_simple: remove unused header file

2016-02-29T10:02:47+00:00

Signed-off-by: Peter Chen 
Signed-off-by: Ulf Hansson

mmc: pwrseq_simple: Make reset-gpios optional to match doc

2016-01-21T12:52:27+00:00

The DT binding doc says reset-gpios is an optional property but the code
currently bails out if it is omitted.

This is a regression since it breaks previously working device trees.
Fix it by restoring the original documented behaviour.

Fixes: ce037275861e ("mmc: pwrseq_simple: use GPIO descriptors array API")
Tested-by: Tony Lindgren 
Signed-off-by: Martin Fuzzey 
Signed-off-by: Ulf Hansson