The PCA9552 lines can be used either for driving LEDs or as GPIOs. The
manual states that for LEDs, the operation is open-drain:
The LSn LED select registers determine the source of the LED data.
00 = output is set LOW (LED on)
01 = output is set high-impedance (LED off; default)
10 = output blinks at PWM0 rate
11 = output blinks at PWM1 rate
For GPIOs it suggests a pull-up so that the open-case drives the line
high:
For use as output, connect external pull-up resistor to the pin
and size it according to the DC recommended operating
characteristics. LED output pin is HIGH when the output is
programmed as high-impedance, and LOW when the output is
programmed LOW through the ‘LED selector’ register. The output
can be pulse-width controlled when PWM0 or PWM1 are used.
Now, I have a hardware design that uses the LED controller to control
LEDs. However, for $reasons, we're using the leds-gpio driver to drive
the them. The reasons are here are a tangent but lead to the discovery
of the inversion, which manifested as the LEDs being set to full
brightness at boot when we expected them to be off.
As we're driving the LEDs through leds-gpio, this means wending our way
through the gpiochip abstractions. So with that in mind we need to
describe an active-low GPIO configuration to drive the LEDs as though
they were GPIOs.
The set() gpiochip callback in leds-pca955x does the following:
...
if (val)
pca955x_led_set(&led->led_cdev, LED_FULL);
else
pca955x_led_set(&led->led_cdev, LED_OFF);
...
Where LED_FULL = 255. pca955x_led_set() in turn does:
...
switch (value) {
case LED_FULL:
ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_LED_ON);
break;
...
Where PCA955X_LS_LED_ON is defined as:
#define PCA955X_LS_LED_ON 0x0 /* Output LOW */
So here we have some type confusion: We've crossed domains from GPIO
behaviour to LED behaviour without accounting for possible inversions
in the process.
Stepping back to leds-gpio for a moment, during probe() we call
create_gpio_led(), which eventually executes:
if (template->default_state == LEDS_GPIO_DEFSTATE_KEEP) {
state = gpiod_get_value_cansleep(led_dat->gpiod);
if (state < 0)
return state;
} else {
state = (template->default_state == LEDS_GPIO_DEFSTATE_ON);
}
...
ret = gpiod_direction_output(led_dat->gpiod, state);
In the devicetree the GPIO is annotated as active-low, and
gpiod_get_value_cansleep() handles this for us:
int gpiod_get_value_cansleep(const struct gpio_desc *desc)
{
int value;
might_sleep_if(extra_checks);
VALIDATE_DESC(desc);
value = _gpiod_get_raw_value(desc);
if (value < 0)
return value;
if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
value = !value;
return value;
}
_gpiod_get_raw_value() in turn calls through the get() callback for the
gpiochip implementation, so returning to our get() implementation in
leds-pca955x we find we extract the raw value from hardware:
static int pca955x_gpio_get_value(struct gpio_chip *gc, unsigned int offset)
{
struct pca955x *pca955x = gpiochip_get_data(gc);
struct pca955x_led *led = &pca955x->leds[offset];
u8 reg = pca955x_read_input(pca955x->client, led->led_num / 8);
return !!(reg & (1 << (led->led_num % 8)));
}
This behaviour is not symmetric with that of set(), where the val is
inverted by the driver.
Closing the loop on the GPIO_ACTIVE_LOW inversions,
gpiod_direction_output(), like gpiod_get_value_cansleep(), handles it
for us:
int gpiod_direction_output(struct gpio_desc *desc, int value)
{
VALIDATE_DESC(desc);
if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
value = !value;
else
value = !!value;
return _gpiod_direction_output_raw(desc, value);
}
All-in-all, with a value of 'keep' for default-state property in a
leds-gpio child node, the current state of the hardware will in-fact be
inverted; precisely the opposite of what was intended.
Rework leds-pca955x so that we avoid the incorrect inversion and clarify
the semantics with respect to GPIO.
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Tested-by: Joel Stanley <joel@jms.id.au>
Tested-by: Matt Spinler <mspinler@linux.vnet.ibm.com>
Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
This should also allow probing to fail when a pca955x chip is not
found on a I2C bus.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
In case platform data provided empty LED name string the resulting
LED class device name would be crippled. Use corresponding LED chip
bit in place of "function" segment of LED class device name then to
make the LEDs at least distinguishable.
Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
Reported-by: Colin King <colin.king@canonical.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Suggested-by: Nate Case <ncase@xes-inc.com>
The PCA955x family of chips are I2C LED blinkers whose pins not used
to control LEDs can be used as general purpose I/Os (GPIOs).
The following adds such a support by defining different operation
modes for the pins (See bindings documentation for more details). The
pca955x driver is then extended with a gpio_chip when some of pins are
operating as GPIOs. The default operating mode is to behave as a LED.
The GPIO support is conditioned by CONFIG_LEDS_PCA955X_GPIO.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
This lets us remove the loop doing the cleanup in case of failure and
also the remove handler of the i2c_driver.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
It will be used in a following patch to define different operation
modes for each pin.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
The driver checks an incorrect flag of functionality of adapter.
When a driver requires i2c_smbus_read_byte_data and
i2c_smbus_write_byte_data, it should check I2C_FUNC_SMBUS_BYTE_DATA
instead I2C_FUNC_I2C.
This patch fixes the problem.
Signed-off-by: Tin Huynh <tnhuynh@apm.com>
Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
This patch enables ACPI support for leds-pca955x driver.
Signed-off-by: Tin Huynh <tnhuynh@apm.com>
Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>
Now the core implements the work queue, remove it from the drivers,
and switch to using brightness_set_blocking op.
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Cc: Nate Case <ncase@xes-inc.com>
Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>
i2c_driver does not need to set an owner because i2c_register_driver()
will set it.
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>
Use the wrapper function for retrieving the platform data instead of
accessing dev->platform_data directly.
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Bryan Wu <cooloney@gmail.com>
CONFIG_HOTPLUG is going away as an option so __devexit is no
longer needed.
Signed-off-by: Bill Pemberton <wfp5p@virginia.edu>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Jan-Simon Moeller <jansimon.moeller@gmx.de>
Acked-by: Bryan Wu <cooloney@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CONFIG_HOTPLUG is going away as an option so __devinit is no longer
needed.
Signed-off-by: Bill Pemberton <wfp5p@virginia.edu>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Jan-Simon Moeller <jansimon.moeller@gmx.de>
Acked-by: Bryan Wu <cooloney@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CONFIG_HOTPLUG is going away as an option so __devexit_p is no longer
needed.
Signed-off-by: Bill Pemberton <wfp5p@virginia.edu>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Jan-Simon Moeller <jansimon.moeller@gmx.de>
Acked-by: Bryan Wu <cooloney@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fixes the following checkpatch warning:
WARNING: Prefer netdev_info(netdev, ... then dev_info(dev, ...
then pr_info(... to printk(KERN_INFO ...
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Bryan Wu <cooloney@gmail.com>
When issuing the following command:
for I in 0 1 2 3 4 5 6 7; do
echo 0 > /sys/class/leds/pca955x\:${I}/brightness;
done
It is possible that all the pca955x_read_ls calls are done sequentially
before any pca955x_write_ls call is done. This updates the LS only to
the last LED update in its set.
Fix this by using a global lock for the pca995x device during
pca955x_led_work. Also used a struct for shared data betreen all LEDs.
[akpm@linux-foundation.org: revert unintentional rename of pca955x_ledsel()]
Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Bryan Wu <bryan.wu@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Factor out some boilerplate code for i2c driver registration
into module_i2c_driver.
Signed-off-by: Axel Lin <axel.lin@gmail.com>
Cc: Haojian Zhuang <hzhuang1@marvell.com>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Michael Hennerich <hennerich@blackfin.uclinux.org>
Cc: Mike Rapoport <mike@compulab.co.il>
Cc: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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
e4a7b9b04d 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: Wolfram Sang <w.sang@pengutronix.de>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Acked-by: Richard Purdie <rpurdie@linux.intel.com>
Acked-by: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.
percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.
http://userweb.kernel.org/~tj/misc/slabh-sweep.py
The script does the followings.
* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.
* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.
* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.
The conversion was done in the following steps.
1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.
2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.
3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.
4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.
5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.
6. percpu.h was updated not to include slab.h.
7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).
* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig
8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.
Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Check the return value of led_classdev_register and unregister all
registered devices, if registering one device fails. Also the dynamic
memory handling is totally bogus. You can't allocate multiple chunks via
kzalloc() and expect them to be in order later. I wonder how this ever
worked.
Signed-off-by: Sven Wegener <sven.wegener@stealer.net>
Acked-by: Nate Case <ncase@xes-inc.com>
Tested-by: Nate Case <ncase@xes-inc.com>
Acked-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This driver supports the PCA9550, PCA9551, PCA9552, and PCA9553
LED driver chips.
Signed-off-by: Nate Case <ncase@xes-inc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Kees Cook