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* pwm: meson: Don't disable PWM when setting duty repeatedlyBichao Zheng2020-01-271-5/+0
| | | | | | | | | | | | | | | | [ Upstream commit a279345807e1e0ae79567a52cfdd9d30c9174a3c ] There is an abnormally low about 20ms,when setting duty repeatedly. Because setting the duty will disable PWM and then enable. Delete this operation now. Fixes: 211ed630753d2f ("pwm: Add support for Meson PWM Controller") Signed-off-by: Bichao Zheng <bichao.zheng@amlogic.com> [ Dropped code instead of hiding it behind a comment ] Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com> Reviewed-by: Neil Armstrong <narmstrong@baylibre.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
* pwm: meson: Consider 128 a valid pre-dividerMartin Blumenstingl2020-01-271-2/+2
| | | | | | | | | | | | | | | | | | [ Upstream commit 51496e4446875726d50a5617a6e0e0dabbc2e6da ] The pre-divider allows configuring longer PWM periods compared to using the input clock directly. The pre-divider is 7 bit wide, meaning it's maximum value is 128 (the register value is off-by-one: 0x7f or 127). Change the loop to also allow for the maximum possible value to be considered valid. Fixes: 211ed630753d2f ("pwm: Add support for Meson PWM Controller") Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com> Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Reviewed-by: Neil Armstrong <narmstrong@baylibre.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
* pwm: meson: Use the spin-lock only to protect register modificationsMartin Blumenstingl2019-06-151-8/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit f173747fffdf037c791405ab4f1ec0eb392fc48e ] Holding the spin-lock for all of the code in meson_pwm_apply() can result in a "BUG: scheduling while atomic". This can happen because clk_get_rate() (which is called from meson_pwm_calc()) may sleep. Only hold the spin-lock when modifying registers to solve this. The reason why we need a spin-lock in the driver is because the REG_MISC_AB register is shared between the two channels provided by one PWM controller. The only functions where REG_MISC_AB is modified are meson_pwm_enable() and meson_pwm_disable() so the register reads/writes in there need to be protected by the spin-lock. The original code also used the spin-lock to protect the values in struct meson_pwm_channel. This could be necessary if two consumers can use the same PWM channel. However, PWM core doesn't allow this so we don't need to protect the values in struct meson_pwm_channel with a lock. Fixes: 211ed630753d2f ("pwm: Add support for Meson PWM Controller") Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com> Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Reviewed-by: Neil Armstrong <narmstrong@baylibre.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
* pwm: meson: Fix mux clock namesJerome Brunet2018-09-151-2/+1
| | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit b96e9eb62841c519ba1db32d036628be3cdef91f ] Current clock name looks like this: /soc/bus@ffd00000/pwm@1b000#mux0 This is bad because CCF uses the clock to create a directory in clk debugfs. With such name, the directory creation (silently) fails and the debugfs entry end up being created at the debugfs root. With this change, the clock name will now be: ffd1b000.pwm#mux0 This matches the clock naming scheme used in the ethernet and mmc driver. It also fixes the problem with debugfs. Fixes: 36af66a79056 ("pwm: Convert to using %pOF instead of full_name") Signed-off-by: Jerome Brunet <jbrunet@baylibre.com> Acked-by: Neil Armstrong <narmstrong@baylibre.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* pwm: Convert to using %pOF instead of full_nameRob Herring2017-07-251-1/+1
| | | | | | | | | | | | | | | | Now that we have a custom printf format specifier, convert users of full_name to use %pOF instead. This is preparation to remove storing of the full path string for each node. Signed-off-by: Rob Herring <robh@kernel.org> Cc: Thierry Reding <thierry.reding@gmail.com> Cc: Carlo Caione <carlo@caione.org> Cc: Kevin Hilman <khilman@baylibre.com> Cc: linux-pwm@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-amlogic@lists.infradead.org Acked-by: Neil Armstrong <narmstrong@baylibre.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
* pwm: meson: Improve PWM calculation precisionJerome Brunet2017-07-061-6/+10
| | | | | | | | | | | | | | | | | | | | | When using input clocks with high rates, such as clk81 (166MHz), the fin_ns = NSEC_PER_SEC / fin_freq can introduce a significant error. Ex: fin_freq = 166666667, NSEC_PER_SEC = 1000000000 fin_ns = 5,9999999 which is, of course, rounded down to 5. This introduces an error of ~20% on the period requested from the PWM. This patch uses ps instead of ns (and 64 bit integers) to perform the calculation. This should give a good enough precision. Fixes: 211ed630753d ("pwm: Add support for Meson PWM Controller") Signed-off-by: Jerome Brunet <jbrunet@baylibre.com> Acked-by: Neil Armstrong <narmstrong@baylibre.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com> squash! pwm: meson: Improve pwm calculation precision
* pwm: meson: Add compatible for the gxbb ao PWMsJerome Brunet2017-07-061-3/+29
| | | | | | | | | | | | | | On the gxbb (and gxl) family, the PWMs of the AO domain require a specific compatible because the possible input clocks are different from the EE PWMs input clocks. Since the number of possible input clocks is also different, the 'num_parents' field is added to all the Meson PWM data. Acked-by: Neil Armstrong <narmstrong@baylibre.com> Signed-off-by: Jerome Brunet <jbrunet@baylibre.com> Reviewed-by: Kevin Hilman <khilman@baylibre.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
* Merge tag 'pwm/for-4.10-rc1' of ↵Linus Torvalds2016-12-151-1/+0
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm Pull pwm updates from Thierry Reding: "This is a very tiny pull request, with just a new driver for HiSilicon BVT SoCs and a cleanup for the Amlogic Meson driver. There are other patches on the list, but my timing was really bad this time and I ended up not having the time to look at them in enough detail to be comfortable merging them" * tag 'pwm/for-4.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm: pwm: Add PWM driver for HiSilicon BVT SOCs pwm: meson: Remove unneeded platform MODULE_ALIAS
| * pwm: meson: Remove unneeded platform MODULE_ALIASJavier Martinez Canillas2016-10-211-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | The Amlogic Meson is a DT-only platform, which means the devices are registered via OF and not using the legacy platform devices support. So there's no need to have a MODULE_ALIAS("platform:meson-pwm") since the reported uevent MODALIAS to user-space will always be the OF one. Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com> Acked-by: Kevin Hilman <khilman@baylibre.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
* | pwm: meson: Add missing spin_lock_init()Axel Lin2016-10-211-0/+1
|/ | | | | | | | The driver uses the spin_lock but does not initialize it. Fix it. Signed-off-by: Axel Lin <axel.lin@ingics.com> Acked-by: Neil Armstrong <narmstrong@baylibre.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
* pwm: meson: Handle unknown ID valuesArnd Bergmann2016-09-081-0/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | When building with -Wmaybe-uninitialized, we get a couple of harmless warnings about three functions in this new driver that don't look safe to the compiler: drivers/pwm/pwm-meson.c: In function 'meson_pwm_get_state': drivers/pwm/pwm-meson.c:355:26: error: 'mask' may be used uninitialized in this function [-Werror=maybe-uninitialized] drivers/pwm/pwm-meson.c: In function 'meson_pwm_disable': drivers/pwm/pwm-meson.c:263:13: error: 'enable' may be used uninitialized in this function [-Werror=maybe-uninitialized] drivers/pwm/pwm-meson.c: In function 'meson_pwm_apply': drivers/pwm/pwm-meson.c:231:13: error: 'clk_shift' may be used uninitialized in this function [-Werror=maybe-uninitialized] drivers/pwm/pwm-meson.c:231:36: error: 'enable' may be used uninitialized in this function [-Werror=maybe-uninitialized] drivers/pwm/pwm-meson.c:231:24: error: 'clk_enable' may be used uninitialized in this function [-Werror=maybe-uninitialized] Specifically, if we have a device with an ID other than 0 or 1, this would result in undefined behavior. This is currently not possible, but the compiler cannot be expected to know this. This patch adds a 'default' clause to let the compiler know what to do instead, which shuts up the warning and makes the code slightly more resiliant in case it gets extended to other identifiers. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Neil Armstrong <narmstrong@baylibre.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
* pwm: Add support for Meson PWM ControllerNeil Armstrong2016-09-081-0/+520
Add support for the PWM controller found in the Amlogic SoCs. This driver supports the Meson8b and GXBB SoCs. Signed-off-by: Neil Armstrong <narmstrong@baylibre.com> Tested-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com> Tested-by: Jerome Brunet <jbrunet@baylibre.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>