The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is (mostly) ignored
and this typically results in resource leaks. To improve here there is a
quest to make the remove callback return void. In the first step of this
quest all drivers are converted to .remove_new() which already returns
void.
Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
lpc18xx_pwm_probe() only ensures clk_rate <= NSEC_PER_SEC, the following
reasoning is right even under this slightly lesser condition.
Fixes: 8933d30c5f ("pwm: lpc18xx: Fix period handling")
Acked-by: Vladimir Zapolskiy <vz@mleia.com>
Link: https://lore.kernel.org/r/20221108153013.132514-1-u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The calculation:
val = (u64)NSEC_PER_SEC * LPC18XX_PWM_TIMER_MAX;
do_div(val, lpc18xx_pwm->clk_rate);
lpc18xx_pwm->max_period_ns = val;
is bogus because with NSEC_PER_SEC = 1000000000,
LPC18XX_PWM_TIMER_MAX = 0xffffffff and clk_rate < NSEC_PER_SEC this
overflows the (on lpc18xx (i.e. ARM32) 32 bit wide) unsigned int
.max_period_ns. This results (dependant of the actual clk rate) in an
arbitrary limitation of the maximal period. E.g. for clkrate =
333333333 (Hz) we get max_period_ns = 9 instead of 12884901897.
So make .max_period_ns an u64 and pass period and duty as u64 to not
discard relevant digits. And also make use of mul_u64_u64_div_u64()
which prevents all overflows assuming clk_rate < NSEC_PER_SEC.
Fixes: 841e6f90bb ("pwm: NXP LPC18xx PWM/SCT driver")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This has various upsides:
- It emits the symbolic name of the error code
- It is silent in the EPROBE_DEFER case and properly sets the defer reason
- It reduces the number of code lines slightly
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
To eventually get rid of all legacy drivers convert this driver to the
modern world implementing .apply().
This pushes a variant of pwm_apply_legacy into the driver that was slightly
simplified because the .set_polarity callback was a noop.
There is no change in behavior.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The per-channel data is available directly in the driver data struct. So
use it without making use of pwm_[gs]et_chip_data().
The relevant change introduced by this patch to lpc18xx_pwm_disable() at
the assembler level (for an arm lpc18xx_defconfig build) is:
push {r3, r4, r5, lr}
mov r4, r0
mov r0, r1
mov r5, r1
bl 0 <pwm_get_chip_data>
ldr r3, [r0, #0]
changes to
ldr r3, [r1, #8]
push {r4, lr}
add.w r3, r0, r3, lsl #2
ldr r3, [r3, #92] ; 0x5c
So this reduces stack usage, has an improved runtime behavior because of
better pipeline usage, doesn't branch to an external function and the
generated code is a bit smaller occupying less memory.
The codesize of lpc18xx_pwm_probe() is reduced by 32 bytes.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Each devm allocations has an overhead of 24 bytes to store the related
struct devres_node additionally to the fragmentation of the allocator.
So allocating 16 struct lpc18xx_pwm_data (which only hold a single int)
adds quite some overhead. Instead put the per-channel data into the
driver data struct and allocate it in one go.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
When a driver calls pwmchip_add() it has to be prepared to immediately
get its callbacks called. So move allocation of driver data and hardware
initialization before the call to pwmchip_add().
This fixes a potential NULL pointer exception and a race condition on
register writes.
Fixes: 841e6f90bb ("pwm: NXP LPC18xx PWM/SCT driver")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
With the previous commit there is no need for the lowlevel driver any
more to specify it it uses two or three cells. So simplify accordingly.
The only non-trival change affects the pwm-rockchip driver: It used to only
support three cells if the hardware supports polarity. Now the default
number depends on the device tree which has to match hardware anyhow
(and if it doesn't the error is just a bit delayed as a PWM handle with
an inverted setting is catched when pwm_apply_state() is called).
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Before pwmchip_remove() returns the PWM is expected to be functional. So
remove the pwmchip before disabling the clock.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Vladimir Zapolskiy <vz@mleia.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Since commit 5e5da1e9fb ("pwm: ab8500: Explicitly allocate pwm chip
base dynamically") all drivers use dynamic ID allocation explicitly. New
drivers are supposed to do the same, so remove support for driver
specified base IDs and drop all assignments in the low-level drivers.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Based on 1 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 as published by
the free software foundation either version 2 of the license
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 24 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Reviewed-by: Steve Winslow <swinslow@gmail.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190528170026.162703968@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Regarding the .request case: The consumer might be interested in taking
over the configured state from the boot loader. So the initially
configured state should be retained.
For the free case the PWM consumer is responsible for disabling the PWM
before calling pwm_put() and there are three subcases to consider:
a) The PWM is already off. Then there is no gain in disabling the PWM
once more.
b) The PWM is still running and there is a good reason for that. (Not
sure this is a valid case, I cannot imagine such a good reason.)
Then it is counterproductive to disable the PWM.
c) The PWM is still running because the consumer failed to disable the
PWM. Then the consumer needs fixing and there is little incentive to
paper over the problem in the backend driver.
This aligns the lpc18xx-sct driver to the other PWM drivers that also
don't reconfigure the hardware in .request and .free.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The lpc-18xx driver currently manipulates the pwm_device struct directly
rather than using the pwm_set_chip_data() function. While the current
method may save a clock cycle or two, using the explicit function call
makes it more obvious that data is set to the local chip data pointer.
Signed-off-by: Olliver Schinagl <oliver@schinagl.nl>
Reviewed-by: Ariel D'Alessandro <ariel@vanguardiasur.com.ar>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Use pwm_get/set_xxx() helpers instead of directly accessing the pwm->xxx
field. Doing that will ease adaptation of the PWM framework to support
atomic update.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The clk API may return 0 on clk_get_rate(), so we should check the
result before using it as a divisor.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: Joachim Eastwood <manabian@gmail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This commit adds support for NXP LPC18xx PWM/SCT.
NXP LPC SoCs family, which includes LPC18xx/LPC43xx, provides a State
Configurable Timer (SCT) which can be configured as a Pulse Width
Modulator. Other SoCs in that family may share the same hardware.
The PWM supports a total of 16 channels, but only 15 can be simultaneously
requested. There's only one period, global to all the channels, thus PWM
driver will refuse setting different values to it, unless there's only one
channel requested.
Signed-off-by: Ariel D'Alessandro <ariel@vanguardiasur.com.ar>
[thierry.reding@gmail.com: remove excessive padding of fields]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
