[ Upstream commit a25351e4c7740eb22561a3ee4ef17611c6f410b0 ]
Implement workaround for ERR051198
(https://www.nxp.com/docs/en/errata/IMX8MN_0N14Y.pdf)
PWM output may not function correctly if the FIFO is empty when a new SAR
value is programmed.
Description:
When the PWM FIFO is empty, a new value programmed to the PWM Sample
register (PWM_PWMSAR) will be directly applied even if the current timer
period has not expired. If the new SAMPLE value programmed in the
PWM_PWMSAR register is less than the previous value, and the PWM counter
register (PWM_PWMCNR) that contains the current COUNT value is greater
than the new programmed SAMPLE value, the current period will not flip
the level. This may result in an output pulse with a duty cycle of 100%.
Workaround:
Program the current SAMPLE value in the PWM_PWMSAR register before
updating the new duty cycle to the SAMPLE value in the PWM_PWMSAR
register. This will ensure that the new SAMPLE value is modified during
a non-empty FIFO, and can be successfully updated after the period
expires.
Write the old SAR value before updating the new duty cycle to SAR. This
avoids writing the new value into an empty FIFO.
This only resolves the issue when the PWM period is longer than 2us
(or <500kHz) because write register is not quick enough when PWM period is
very short.
Reproduce steps:
cd /sys/class/pwm/pwmchip1/pwm0
echo 2000000000 > period # It is easy to observe by using long period
echo 1000000000 > duty_cycle
echo 1 > enable
echo 8000 > duty_cycle # One full high pulse will be seen by scope
Fixes: 166091b1894d ("[ARM] MXC: add pwm driver for i.MX SoCs")
Reviewed-by: Jun Li <jun.li@nxp.com>
Signed-off-by: Clark Wang <xiaoning.wang@nxp.com>
Signed-off-by: Frank Li <Frank.Li@nxp.com>
Link: https://lore.kernel.org/r/20241008194123.1943141-1-Frank.Li@nxp.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit cc6a931d1f3b412263d515fd93b21fc0ca5147fe upstream.
The modulo register defines the period of the edge-aligned PWM mode
(which is the only mode implemented). The reference manual states:
"The EPWM period is determined by (MOD + 0001h) ..." So the value that
is written to the MOD register must therefore be one less than the
calculated period length. Return -EINVAL if the calculated length is
already zero.
A correct MODULO value is particularly relevant if the PWM has to output
a high frequency due to a low period value.
Fixes: 738a1cfec2ed ("pwm: Add i.MX TPM PWM driver support")
Cc: stable@vger.kernel.org
Signed-off-by: Erik Schumacher <erik.schumacher@iris-sensing.com>
Link: https://lore.kernel.org/r/1a3890966d68b9f800d457cbf095746627495e18.camel@iris-sensing.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To eventually get rid of all legacy drivers convert this driver to the
modern world implementing .apply(). The commit which brings these
changes is `5ec803edcb703fe379836f13560b79dfac79b01d` on the uplink
kernel.
Bug: 332793240
Change-Id: I385f487c474ca2d52a9f3bb4e8afc3843eb4d9f8
Signed-off-by: Karan Bhagoji <karan.rb@samsung.com>
Signed-off-by: Hyunki Koo <hyunki00.koo@samsung.com>
[ Upstream commit 7346e7a058a2c9aa9ff1cc699c7bf18a402d9f84 ]
When the state changes from enabled to disabled, polarity, duty_cycle
and period are not configured in hardware and TIM_CCER_CCxE is just
cleared. However if the state changes from one disabled state to
another, all parameters are written to hardware because the early exit
from stm32_pwm_apply() is only taken if the pwm is currently enabled.
This yields surprises like: Applying
{ .period = 1, .duty_cycle = 0, .enabled = false }
succeeds if the pwm is initially on, but fails if it's already off
because 1 is a too small period.
Update the check for lazy disable to always exit early if the target
state is disabled, no matter what is currently configured.
Fixes: 7edf7369205b ("pwm: Add driver for STM32 plaftorm")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://lore.kernel.org/r/20240703110010.672654-2-u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit c45fcf46ca2368dafe7e5c513a711a6f0f974308 upstream.
If period_ns is small, prd might well become 0. Catch that case because
otherwise with
regmap_write(priv->regmap, TIM_ARR, prd - 1);
a few lines down quite a big period is configured.
Fixes: 7edf7369205b ("pwm: Add driver for STM32 plaftorm")
Cc: stable@vger.kernel.org
Reviewed-by: Trevor Gamblin <tgamblin@baylibre.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://lore.kernel.org/r/b86f62f099983646f97eeb6bfc0117bb2d0c340d.1718979150.git.u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 9320fc509b87b4d795fb37112931e2f4f8b5c55f upstream.
dev_err_probe() is only supposed to be used in probe functions. While it
probably doesn't hurt, both the EPROBE_DEFER handling and calling
device_set_deferred_probe_reason() are conceptually wrong in the request
callback. So replace the call by dev_err() and a separate return
statement.
This effectively reverts commit c0bfe9606e03 ("pwm: jz4740: Simplify
with dev_err_probe()").
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20240106141302.1253365-2-u.kleine-koenig@pengutronix.de
Fixes: c0bfe9606e03 ("pwm: jz4740: Simplify with dev_err_probe()")
Cc: stable@vger.kernel.org
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 19f1016ea9600ed89bc24247c36ff5934ad94fbb ]
Make the driver take over hardware state without disabling in .probe()
and enable the clock for each enabled channel.
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
[ukleinek: split off from a patch that also implemented .get_state()]
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Fixes: 7edf7369205b ("pwm: Add driver for STM32 plaftorm")
Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 41fa8f57c0d269243fe3bde2bce71e82c884b9ad ]
Use hweight32() to count the CCxE bits in stm32_pwm_detect_channels().
Since the return value is assigned to chip.npwm, change it to unsigned
int as well.
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Stable-dep-of: 19f1016ea960 ("pwm: stm32: Fix enable count for clk in .probe()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit e9bc4411548aaa738905d37851a0146c16b3bb21 ]
The suspend/resume functions currently utilize
clk_disable()/clk_enable() respectively which may be no-ops with certain
clock providers such as SCMI. Fix this to use clk_disable_unprepare()
and clk_prepare_enable() respectively as we should.
Fixes: 3a9f5957020f ("pwm: Add Broadcom BCM7038 PWM controller support")
Signed-off-by: Florian Fainelli <florian.fainelli@broadcom.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 2d6812b41e0d832919d72c72ebddf361df53ba1b ]
Instead of using one allocation per capture channel, use a single one. Also
store it in driver data instead of chip data.
This has several advantages:
- driver data isn't cleared when pwm_put() is called
- Reduces memory fragmentation
Also register the pwm chip only after the per capture channel data is
initialized as the capture callback relies on this initialization and it
might be called even before pwmchip_add() returns.
It would be still better to have struct sti_pwm_compat_data and the
per-channel data struct sti_cpt_ddata in a single memory chunk, but that's
not easily possible because the number of capture channels isn't known yet
when the driver data struct is allocated.
Fixes: e926b12c611c ("pwm: Clear chip_data in pwm_put()")
Reported-by: George Stark <gnstark@sberdevices.ru>
Fixes: c97267ae831d ("pwm: sti: Add PWM capture callback")
Link: https://lore.kernel.org/r/20230705080650.2353391-7-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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit fd3ae02bb66f091e55f363d32eca7b4039977bf5 ]
Using gotos for conditional code complicates this code significantly.
Convert the code to simple conditional blocks to increase readability.
Suggested-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Stable-dep-of: 2d6812b41e0d ("pwm: sti: Reduce number of allocations and drop usage of chip_data")
Signed-off-by: Sasha Levin <sashal@kernel.org>
