Dividing by the result of a division looses precision. Consider for example
clk_rate = 33000000 and period_ns = 500001. Then
clk_rate / (NSEC_PER_SEC / period_ns)
has the exact value 16500.033, but in C this evaluates to 16508. It gets
worse for even bigger values of period_ns, so with period_ns = 500000001,
the exact result is 16500000.033 while in C we get 33000000.
For that reason use
clk_rate * period_ns / NSEC_PER_SEC
instead which doesn't suffer from this problem. To ensure this doesn't
overflow add a safeguard check for clk_rate.
Note that duty > period can never happen, so the respective check can be
dropped.
Incidentally this fixes a division by zero if period_ns > NSEC_PER_SEC.
Another side effect is that values bigger than INT_MAX for period and
duty_cyle are not wrongly discarded any more.
Fixes: 99b82abb0a ("pwm: Add Renesas TPU PWM driver")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The newly computed register values are intended to exactly match the
previously computed values. The main improvement is that the prescaler
is computed without a loop that involves two divisions in each step.
This uses the fact, that prescalers[i] = 1 << (2 * i).
Assuming a moderately smart compiler, the needed number of divisions for
the case where the requested period is too big, is reduced from 5 to 2.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The driver used "pwm" for struct tpu_pwm_device pointers. This name is
usually only used for struct pwm_device pointers which this driver calls
"_pwm". So rename to the driver data pointers to "tpd" which then allows
to drop the underscore from "_pwm".
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
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().
As pwm->state might not be updated in tpu_pwm_apply() before calling
tpu_pwm_config(), an additional parameter is needed for tpu_pwm_config()
to not change the implemented logic.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This simplifies an error path in .probe() and allows to drop the .remove()
function.
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The added benefit is that the error code is mentioned in the error message
and its usage is a bit more compact than open coding it. This also
improves behaviour in case devm_clk_get() returns -EPROBE_DEFER.
While touching this code, consistently start error messages with upper
case.
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
pwmchip_remove() returns always 0. Don't use the value to make it
possible to eventually change the function to return void. Also the
driver core ignores the return value of tpu_remove().
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>
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>
During device probe, the message
TPU PWM -1 registered
is printed.
While the "-1" looks suspicious, it is perfectly normal for a device
instantiated from DT.
Remove the message, as there are no non-DT users left, and other drivers
don't print such messages either.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Runtime PM should be enabled before calling pwmchip_add(), as PWM users
can appear immediately after the PWM chip has been added.
Likewise, Runtime PM should always be disabled after the removal of the
PWM chip, even if the latter failed.
Fixes: 99b82abb0a ("pwm: Add Renesas TPU PWM driver")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Remove support for the SH7372 (SH-Mobile AP4) from the renesas-tpu
driver.
Commit edf4100906 ("ARM: shmobile: sh7372 dtsi: Remove Legacy
file") removed this SoC from the kernel in v4.1.
Acked-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
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>
The struct is not used anymore and the polarity initialization will be
done using the PWM lookup table (or device tree).
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The site-specific OOM messages are unnecessary, because they
duplicate the MM subsystem generic OOM message.
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Remove unneeded error handling on the result of a call to
platform_get_resource when the value is passed to devm_ioremap_resource.
Move the call to platform_get_resource adjacent to the call to
devm_ioremap_resource to make the connection between them more clear.
A simplified version of the semantic patch that makes this change is as
follows: (http://coccinelle.lip6.fr/)
// <smpl>
@@
expression pdev,res,n,e,e1;
expression ret != 0;
identifier l;
@@
- res = platform_get_resource(pdev, IORESOURCE_MEM, n);
... when != res
- if (res == NULL) { ... \(goto l;\|return ret;\) }
... when != res
+ res = platform_get_resource(pdev, IORESOURCE_MEM, n);
e = devm_ioremap_resource(e1, res);
// </smpl>
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Specify DT bindings for the TPU PWM controller and add OF support to the
driver.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Acked-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This driver can be built as module, add MODULE_ALIAS to make module auto loading
work.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
In case of error, the function devm_ioremap_resource() returns ERR_PTR()
and never returns NULL. The NULL test in the return value check should
be replaced with IS_ERR().
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Reviewed-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The Timer Pulse Unit (TPU) is a 4-channels 16-bit timer used to generate
waveforms. This driver exposes PWM functions through the PWM API for
other drivers to use.
The code is loosely based on the leds-renesas-tpu driver by Magnus Damm
and the TPU PWM driver shipped in the Armadillo EVA 800 kernel sources.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Tested-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Uwe Kleine-König