Problems:
- When duty_ns == period_ns, the full OFF bit was not cleared and the
PWM output of the PCA9685 stayed off.
- When duty_ns == period_ns and the catch-all channel was used, the
ALL_LED_OFF_L register was not cleared.
- The full ON bit was not cleared when setting the OFF time, therefore
the exact OFF time was ignored when setting a duty_ns < period_ns
Solution: Clear both OFF registers when setting full ON and clear the
full ON bit when changing the OFF registers.
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Signed-off-by: Clemens Gruber <clemens.gruber@pqgruber.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Update the driver so that settings are applied in accordance with the
most recent version of the hardware spec. The revised sequence clears
the trigger bit, waits 400ns, writes settings, sets the trigger bit,
and waits another 400ns. This corrects an issue where occasionally a
requested change was not properly reflected in the PWM output.
Reviewed-by: Arun Ramamurthy <arunrama@broadcom.com>
Reviewed-by: Scott Branden <sbranden@broadcom.com>
Tested-by: Scott Branden <sbranden@broadcom.com>
Reviewed-by: Tim Kryger <tim.kryger@gmail.com>
Signed-off-by: Jonathan Richardson <jonathar@broadcom.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.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: Thierry Reding <thierry.reding@gmail.com>
Padding initializers so that assignment operators align is bound to lead
to inconsistencies or churn. Single spaces around the assignment is just
fine.
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The current code will check for polarity in a boolean way. While it is
correct that polarity is either normal or inversed, make it more obvious
that it's an enumeration by using a switch statement and explicit
matches on the enumeration values.
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Use the pwm_get_xxx() helpers instead of directly accessing the fields
in struct pwm_device. This will allow us to smoothly move to the atomic
update approach.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Some PWM drivers are testing the PWMF_ENABLED flag. Create a helper
function to hide the logic behind enabled test. This will allow us to
smoothly move from the current approach to an atomic PWM update
approach.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Pull pwm updates from Thierry Reding:
"This has a couple of fixes for Atmel, Samsung and Broadcom drivers.
Some preparatory patches for more upcoming Intel work is included as
well"
* tag 'pwm/for-4.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm:
pwm: lpss: pci: Add support for Broxton platform
pwm: bcm-kona: Don't set polarity in probe
pwm: Add pwmchip_add_with_polarity() API
pwm: atmel: Fix incorrect CDTY value after disabling
pwm: atmel: Fix incorrect CDTY value after enabling
pwm: samsung: Use MODULE_DEVICE_TABLE() to include OF modalias
pwm: Add support to remove registered consumer lookup tables
Omit setting the polarity to normal during probe and instead use the new
pwmchip_add_with_polarity() function to register a PWM chip with inverse
polarity by default for all channels to reflect the hardware default.
Signed-off-by: Arun Ramamurthy <arunrama@broadcom.com>
Reviewed-by: Ray Jui <rjui@broadcom.com>
Signed-off-by: Scott Branden <sbranden@broadcom.com>
Signed-off-by: Tim Kryger <tim.kryger@gmail.com>
Signed-off-by: Jonathan Richardson <jonathar@broadcom.com>
[thierry.reding@gmail.com: use pwmchip_add_with_polarity()]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Add a new function to register a PWM chip with channels that have their
initial polarity as specified by an additional parameter. This benefits
drivers of controllers that by default operate with inversed polarity
by removing the need to modify the polarity during initialization.
Signed-off-by: Tim Kryger <tim.kryger@gmail.com>
Signed-off-by: Jonathan Richardson <jonathar@broadcom.com>
[thierry.reding@gmail.com: export pwmchip_add_with_polarity()]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
pwm-leds calls .config() and .disable() in a row. This exhibits that it
may happen that the channel gets disabled before CDTY has been updated
with CUPD. The issue gets quite worse with long periods. So, ensure that
at least one period has past before disabling the channel by polling
ISR.
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Tested-by: Gaël PORTAY <gael.portay@gmail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
CUPD is not flushed before enabling the channel so it will update
CDTY/CPRD just after one period. So we always set CUPD, even when the
channel is not enabled.
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
If the pwm-samsung driver is built as a module, modalias information is
not filled so the module is not autoloaded. Use the MODULE_DEVICE_TABLE()
macro to export the OF device ID so the module contains that information.
Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The PWM hardware on Pistachio platform has a maximum timebase steps
value to 255. To fix it, let's introduce a compatible-specific
data structure to contain the SoC-specific details and use it to
specify a maximum timebase.
Also, let's limit the minimum timebase to 16 steps, to allow a sane
range of duty cycle steps.
Fixes: 277bb6a29e ("pwm: Imagination Technologies PWM DAC driver")
Signed-off-by: Naidu Tellapati <naidu.tellapati@imgtec.com>
Signed-off-by: Ezequiel Garcia <ezequiel.garcia@imgtec.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
When disabling the Samsung PWM the output state remains at the level it
was at the end of a PWM cycle. In other words, calling pwm_disable()
when at 100% duty cycle will keep the output active, while at all other
settings the output will go/stay inactive. On top of that the Samsung
PWM settings are double-buffered, which means the new settings only get
applied at the start of a new PWM cycle.
This results in a race if the PWM is at 100% duty cycle and a driver
calls:
pwm_config(pwm, 0, period);
pwm_disable(pwm);
In this case the PWMs output will unexpectedly stay active, unless a new
PWM cycle happened to start between the register writes in pwm_config()
and pwm_disable(). As far as I can tell this is a regression introduced
by 3bdf878, before that a call to pwm_config() would call
pwm_samsung_enable() which, while heavy-handed, made sure the expected
settings were live.
To resolve this, while not re-introducing the issues 3bdf878 (flickering
as the PWM got reset while in a PWM cycle) fixed, only force an update
of the settings when at 100% duty cycle, which shouldn't have any
noticeable effect on the output but is enough to ensure the behaviour is
as expected on disable.
Signed-off-by: Sjoerd Simons <sjoerd.simons@collabora.co.uk>
Reviewed-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Acked-by: Lukasz Majewski <l.majewski@samsung.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The driver computes which clock divider it sould be using from the
requested period. This computation assumes that the link between the
register value and the actual divider value is raising 2 to the power of
the registry value.
div = 1 << regvalue
This is true only for the first 5 values out of 8. Next values are 64,
256 and, 1024 - instead of 32, 64, 128.
This affects only the users requesting a period > 0.04369s.
Replace the computation with a look-up table.
Signed-off-by: Gaetan Hug <ghug@induct.be>
Acked-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The regmap_config struct may be const because it is not modified by the
driver and regmap_init() accepts pointer to const.
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Instead of using the literal value for the number of nanoseconds per
second, use the macro instead to increase readability.
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The of_node_put() function tests whether its argument is NULL and then
returns immediately. Thus the test around the call is not needed.
This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Clemens Gruber
Jonathan Richardson
Krzysztof Kozlowski
Thierry Reding
Boris Brezillon
Linus Torvalds
Qipeng Zha
Arun Ramamurthy
Tim Kryger
Alexandre Belloni
Javier Martinez Canillas
Naidu Tellapati
Shobhit Kumar
Sjoerd Simons
Gaetan Hug
Nicolas Ferre
Markus Elfring