05 Sep, 2016
1 commit
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Exported pwm channels aren't removed before the pwmchip and are
leaked. This results in invalid sysfs files. This fix removes
all exported pwm channels before chip removal.Signed-off-by: David Hsu
Fixes: 76abbdde2d95 ("pwm: Add sysfs interface")
Signed-off-by: Thierry Reding
25 Jul, 2016
1 commit
10 Jun, 2016
2 commits
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Supply a PWM capture callback op in order to pass back information
obtained by running analysis on a PWM signal. This would normally (at
least during testing) be called from the sysfs routines with a view to
printing out PWM capture data which has been encoded into a string.Signed-off-by: Lee Jones
[thierry.reding@gmail.com: make capture data unsigned int for symmetry]
Signed-off-by: Thierry Reding -
It seems like in the process of refactoring pwm_config() to utilize the
newly-introduced pwm_apply_state() API, some args/bounds checking was
dropped.In particular, I noted that we are now allowing invalid period
selections, e.g.:# echo 1 > /sys/class/pwm/pwmchip0/export
# cat /sys/class/pwm/pwmchip0/pwm1/period
100
# echo 101 > /sys/class/pwm/pwmchip0/pwm1/duty_cycle
[... driver may or may not reject the value, or trigger some logic bug ...]It's better to see:
# echo 1 > /sys/class/pwm/pwmchip0/export
# cat /sys/class/pwm/pwmchip0/pwm1/period
100
# echo 101 > /sys/class/pwm/pwmchip0/pwm1/duty_cycle
-bash: echo: write error: Invalid argumentThis patch reintroduces some bounds checks in both pwm_config() (for its
signed parameters; we don't want to convert negative values into large
unsigned values) and in pwm_apply_state() (which fix the above described
behavior, as well as other potential API misuses).Fixes: 5ec803edcb70 ("pwm: Add core infrastructure to allow atomic updates")
Signed-off-by: Brian Norris
Acked-by: Boris Brezillon
Signed-off-by: Thierry Reding
17 May, 2016
11 commits
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The PWM states make it possible to also output the polarity, duty cycle
and period information in the debugfs summary output. This simplifies
gathering information about PWMs without needing to walk through the
sysfs attributes of every PWM.Signed-off-by: Heiko Stuebner
Signed-off-by: Boris Brezillon
[thierry.reding@gmail.com: use more spaces in debugfs output]
Signed-off-by: Thierry Reding -
Replace legacy pwm_get/set_xxx() and pwm_config/enable/disable() calls
by pwm_get/apply_state().Signed-off-by: Boris Brezillon
Signed-off-by: Thierry Reding -
Add an ->apply() method to the pwm_ops struct to allow PWM drivers to
implement atomic updates. This method is preferred over the ->enable(),
->disable() and ->config() methods if available.Add the pwm_apply_state() function to the PWM user API.
Note that the pwm_apply_state() does not guarantee the atomicity of the
update operation, it all depends on the availability and implementation
of the ->apply() method.pwm_enable/disable/set_polarity/config() are now implemented as wrappers
around the pwm_apply_state() function.pwm_adjust_config() is allowing smooth handover between the bootloader
and the kernel. This function tries to adapt the current PWM state to
the PWM arguments coming from a PWM lookup table or a DT definition
without changing the duty_cycle/period proportion.Signed-off-by: Boris Brezillon
[thierry.reding@gmail.com: fix a couple of typos]
Signed-off-by: Thierry Reding -
Add a ->get_state() function to the pwm_ops struct to let PWM drivers
initialize the PWM state attached to a PWM device.Signed-off-by: Boris Brezillon
Signed-off-by: Thierry Reding -
Prepare the transition to PWM atomic update by moving the enabled and
disabled state into the pwm_state struct. This way we can easily update
the whole PWM state by copying the new state in the ->state field.Signed-off-by: Boris Brezillon
Signed-off-by: Thierry Reding -
The PWM state, represented by its period, duty_cycle and polarity is
currently directly stored in the PWM device. Declare a pwm_state
structure embedding those field so that we can later use this struct
to atomically update all the PWM parameters at once.All pwm_get_xxx() helpers are now implemented as wrappers around
pwm_get_state().Signed-off-by: Boris Brezillon
Signed-off-by: Thierry Reding -
Before the introduction of pwm_args, the core was resetting the PWM
period and polarity states to the reference values (those provided
through the DT, a PWM lookup table or hardcoded in the driver).Now that all PWM users are correctly using pwm_args to configure their
PWM device, we can safely remove the pwm_apply_args() call in pwm_get()
and of_pwm_get().We can also get rid of the pwm_set_period() call in pwm_apply_args(),
because PWM users are now directly using pargs->period instead of
pwm_get_period(). By doing that we avoid messing with the current PWM
period.The only remaining bit in pwm_apply_args() is the initial polarity
setting, and it should go away when all PWM users have been patched to
use the atomic API (with this API the polarity will be set along with
other PWM arguments when configuring the PWM).Signed-off-by: Boris Brezillon
Signed-off-by: Thierry Reding -
PWM devices are not protected against concurrent accesses. The lock in
struct pwm_device might let PWM users think it is, but it's actually
only protecting the enabled state.Removing this lock should be fine as long as all PWM users are aware
that accesses to the PWM device have to be serialized, which seems to be
the case for all of them except the sysfs interface. Patch the sysfs
code by adding a lock to the pwm_export struct and making sure it's
taken for all relevant accesses to the exported PWM device.Signed-off-by: Boris Brezillon
Signed-off-by: Thierry Reding -
pwm_apply_args() is supposed to initialize a PWM device according to the
arguments provided by the DT or the PWM lookup, but this function was
called inside pwm_device_request(), which in turn was called before the
core had a chance to initialize the pwm->args fields.Fix that by calling pwm_apply_args directly in pwm_get() and of_pwm_get()
after initializing pwm->args field.This commit also fixes an invalid pointer dereference introduced by
commit e39c0df1be5a ("pwm: Introduce the pwm_args concept").Signed-off-by: Boris Brezillon
Fixes: e39c0df1be5a ("pwm: Introduce the pwm_args concept")
Signed-off-by: Thierry Reding
03 May, 2016
3 commits
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kcalloc() should be preferred for allocations of arrays over kzalloc()
with multiplication.Signed-off-by: Thierry Reding
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checkpatch requires that declarations be separated from code by a blank
line. Add one for readability and to silence the warning.Signed-off-by: Thierry Reding
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Currently the PWM core mixes the current PWM state with the per-platform
reference config (specified through the PWM lookup table, DT definition
or directly hardcoded in PWM drivers).Create a struct pwm_args to store this reference configuration, so that
PWM users can differentiate between the current and reference
configurations.Patch all places where pwm->args should be initialized. We keep the
pwm_set_polarity/period() calls until all PWM users are patched to use
pwm_args instead of pwm_get_period/polarity().Signed-off-by: Boris Brezillon
[thierry.reding@gmail.com: reword kerneldoc comments]
Signed-off-by: Thierry Reding
21 Jan, 2016
1 commit
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Commit d1cd21427747 ("pwm: Set enable state properly on failed call to
enable") introduced a mutex that is needed to protect internal state of
PWM devices. Since that mutex is acquired in pwm_set_polarity() and in
pwm_enable() and might potentially block, all PWM devices effectively
become "might sleep".It's rather pointless to keep the .can_sleep field around, but given
that there are external users let's postpone the removal for the next
release cycle.Signed-off-by: Thierry Reding
10 Nov, 2015
2 commits
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When looking up a PWM using the lookup table, assume that all entries
will have been added already, so failure to find a match means that no
corresponding entry has been registered.This fixes an issue where -EPROBE_DEFER would be returned if the PWM
lookup table is empty. After this fix, -EPROBE_DEFER is reserved for
situations where no provider has yet registered for a matching entry.Signed-off-by: Thierry Reding
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The pwm_enable() function didn't clear the enabled bit if a call to the
driver's ->enable() callback returned an error. The result was that the
state of the PWM core was wrong. Clearing the bit when enable returns
an error ensures the state is properly set.Tested-by: Jonathan Richardson
Reviewed-by: Dmitry Torokhov
Signed-off-by: Jonathan Richardson
[thierry.reding@gmail.com: add missing kerneldoc for the lock]
Signed-off-by: Thierry Reding
17 Aug, 2015
2 commits
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Clean up kerneldoc in preparation for including the PWM documentation in
DocBook.Signed-off-by: Thierry Reding
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Remove useless tabs used for padding in structure definitions as well as
some blank lines.Signed-off-by: Thierry Reding
20 Jul, 2015
1 commit
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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
Signed-off-by: Thierry Reding
12 Jun, 2015
1 commit
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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
Signed-off-by: Jonathan Richardson
[thierry.reding@gmail.com: export pwmchip_add_with_polarity()]
Signed-off-by: Thierry Reding
06 May, 2015
1 commit
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In case some drivers are unloading, they can remove lookup tables which
they had registered during their load time to avoid redundant entries if
loaded again.CC: Samuel Ortiz
Cc: Linus Walleij
Cc: Alexandre Courbot
Cc: Thierry Reding
Signed-off-by: Shobhit Kumar
Signed-off-by: Thierry Reding
23 Apr, 2015
1 commit
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For platforms that don't support DT, some early MFD modules can register
lookup tables. Remove the __init annotation so that this works. This is
similar to gpio_add_lookup_table() which allows late additions.CC: Samuel Ortiz
Cc: Linus Walleij
Cc: Alexandre Courbot
Cc: Thierry Reding
Signed-off-by: Shobhit Kumar
Signed-off-by: Thierry Reding
03 Feb, 2015
1 commit
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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
Signed-off-by: Thierry Reding
29 Aug, 2014
1 commit
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With some versions of gcc (e.g. 4.1.2):
drivers/pwm/core.c: In function ‘pwm_get’:
drivers/pwm/core.c:610: warning: ‘polarity’ may be used uninitialized in this function
drivers/pwm/core.c:609: warning: ‘period’ may be used uninitialized in this functionWhile these are false positives, we can get rid of them by refactoring
the code to store a pointer to the best match, as suggested before by
Thierry Reding. This does require moving the mutex_unlock() down.Fixes: d717ea73e36dd565 ("pwm: Fix period and polarity in pwm_get() for non-perfect matches")
Signed-off-by: Geert Uytterhoeven
Signed-off-by: Thierry Reding
25 Aug, 2014
1 commit
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Since we cannot make sure the 'chip->npwm' will always be none zero here,
and then if either equal to zero, the kzalloc() will return ZERO_SIZE_PTR,
which equals to ((void *)16).So this patch fix this with just doing the zero check before calling kzalloc().
Signed-off-by: Xiubo Li
Signed-off-by: Thierry Reding
18 Aug, 2014
1 commit
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If pwm_get() finds a look-up entry with a perfect match (both dev_id and
con_id match), the loop is aborted, and "p" still points to the correct
struct pwm_lookup.If only an entry with a matching dev_id or con_id is found, the loop
terminates after traversing the whole list, and "p" now points to
arbitrary memory, not part of the pwm_lookup list.
Then pwm_set_period() and pwm_set_polarity() will set random values for
period resp. polarity.To fix this, save period and polarity when finding a new best match,
just like is done for chip (for the provider) and index.This fixes the LCD backlight on r8a7740/armadillo-legacy, which was fed
period 0 and polarity -1068821144 instead of 33333 resp. 1.Fixes: 3796ce1d4d4b ("pwm: add period and polarity to struct pwm_lookup")
Signed-off-by: Geert Uytterhoeven
Cc: stable@vger.kernel.org
Signed-off-by: Thierry Reding
21 May, 2014
1 commit
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Add period and polarity members to struct pwm_lookup so that platforms
using the lookup table can be treated the same way as those using the
device tree.Signed-off-by: Alexandre Belloni
Signed-off-by: Thierry Reding
20 Dec, 2013
1 commit
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For a constant format without additional arguments, use seq_puts()
instead of seq_printf(). Also, the following checkpatch warning is
fixed.WARNING: Prefer seq_puts to seq_printf
Signed-off-by: Jingoo Han
Signed-off-by: Thierry Reding
03 Sep, 2013
1 commit
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Don't redefine a PWM_SPEC_POLARITY macro with a value identical to
PWM_POLARITY_INVERTED, use the PWM DT macro directly.Signed-off-by: Laurent Pinchart
Reviewed-by: Stephen Warren
Signed-off-by: Thierry Reding
21 Jun, 2013
1 commit
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Add a simple sysfs interface to the generic PWM framework.
/sys/class/pwm/
`-- pwmchipN/ for each PWM chip
|-- export (w/o) ask the kernel to export a PWM channel
|-- npwm (r/o) number of PWM channels in this PWM chip
|-- pwmX/ for each exported PWM channel
| |-- duty_cycle (r/w) duty cycle (in nanoseconds)
| |-- enable (r/w) enable/disable PWM
| |-- period (r/w) period (in nanoseconds)
| `-- polarity (r/w) polarity of PWM (normal/inversed)
`-- unexport (w/o) return a PWM channel to the kernelBased on work by Lars Poeschel.
Signed-off-by: H Hartley Sweeten
Cc: Thierry Reding
Cc: Lars Poeschel
Cc: Ryan Mallon
Cc: Rob Landley
Signed-off-by: Thierry Reding
10 Jun, 2013
1 commit
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The allocated object should be the size of what the pointer is pointing
to and not the size of the pointer itself.Signed-off-by: Wolfram Sang
Reviewed-by: Andy Shevchenko
Signed-off-by: Thierry Reding
27 Feb, 2013
1 commit
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Pull PWM changes from Thierry Reding:
"A new driver has been added to support the PWM mode of the timer
counter blocks found on Atmel AT91 SoCs. The VT8500 driver now
supports changing the PWM signal polarity and the TI drivers (EHRPWM
and ECAP) gained suspend and resume functionality.User drivers can now query the core for whether access to a PWM device
will sleep (if the PWM chip is on a slow bus such as I2C or SPI).The pwm-backlight driver now handles the backlight BL_CORE_FBBLANK
state in addition to the FB layer's blanking states.To round things off, a few fixes and cleanups are also included"
* tag 'for-3.9-rc1' of git://gitorious.org/linux-pwm/linux-pwm:
pwm: twl: Use to_twl() instead of container_of()
pwm: tegra: assume CONFIG_OF
pwm_backlight: Validate dft_brightness in main probe function
pwm: Export pwm_{set,get}_chip_data()
pwm: Make Kconfig entries more consistent
pwm: Add can_sleep property to drivers
pwm: Add pwm_can_sleep() as exported API to users
pwm-backlight: handle BL_CORE_FBBLANK state
pwm: pwm-tiecap: Low power sleep support
pwm: pwm-tiehrpwm: Low power sleep support
pwm: pwm-tiehrpwm: Update the clock handling of pwm-tiehrpwm driver
pwm: vt8500: Add polarity support
pwm: vt8500: Register write busy test performed incorrectly
pwm: atmel: add Timer Counter Block PWM driver
02 Feb, 2013
2 commits
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When booted with DT users can use devm version of of_pwm_get() to benefit
from automatic resource release.Signed-off-by: Peter Ujfalusi
Acked-by: Thierry Reding
Signed-off-by: Bryan Wu -
Allow client driver to use of_pwm_get() to get the PWM they need. This
is needed for drivers which handle more than one PWM separately, like
leds-pwm driver, which have:pwmleds {
compatible = "pwm-leds";
kpad {
label = "omap4::keypad";
pwms = ;
max-brightness = ;
};charging {
label = "omap4:green:chrg";
pwms = ;
max-brightness = ;
};
};in the dts files.
Signed-off-by: Peter Ujfalusi
Acked-by: Thierry Reding
Signed-off-by: Bryan Wu
30 Jan, 2013
1 commit
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When building a driver as a module, these functions need to be exported
for linking to succeed.Signed-off-by: Thierry Reding
