Commit Graph

628 Commits

Author SHA1 Message Date
Linus Torvalds
cece6460c2 pwm: Changes for v5.2-rc1
Nothing out of the ordinary this cycle. The bulk of this is a collection
 of fixes for existing drivers and some cleanups. There's one new driver
 for i.MX SoCs and addition of support for some new variants to existing
 drivers.
 -----BEGIN PGP SIGNATURE-----
 
 iQJNBAABCAA3FiEEiOrDCAFJzPfAjcif3SOs138+s6EFAlzVW/MZHHRoaWVycnku
 cmVkaW5nQGdtYWlsLmNvbQAKCRDdI6zXfz6zoVgJEACIqcHeP5SrGv+Bh5xoAsNL
 HNLu72QOTVFYICBPSTqsS9QgGvkeZErv86dheYp6MSJHuRCGu/d4Vlp6iY8YmiS0
 i3Vi9Ib8sGsbC2kKJSsLnAO7d1JrDkyxYS8sSGSR0G2xKZA1dgXVqtAEdOubUU0x
 /HrzpP8uSoSiKflEfGtU3OykAdY8b1UBtWuC+KxVP2z5A2IAJchYQcXQ3v+kVbvT
 Jp+mYbYfViwb40JKFkg67hm7y494LFAMZhInzv5ImQXl1ji+C2VPGfqBdlxwgW8g
 +OyP0Conh6oHlEB4Wc7xfWec0PYJee9hNlXR30L+a1OCTisnOq7aHHjf6+ej7NDq
 KeQPEt9r8URgRMbfPvL70TRk46QeToeC07BO7aEGK3gd2C2c6ZoFmyhhauM6j2z0
 eL8xK7WnynKCUrQ0tgQhv8AZkZE/Hp2ddgicyu0ARECugRiqd/uVNeip3M3TkPmV
 Zv0nRZzhFUk+t0DNX6krEVzvkaFznzWGDK6PGeHHbNdR58GaRnYzM0WXytYqUNGa
 +kryN/sj0vgzVj+ATxvDfVYqAtZMYcXvZMJQhfjNAPP89F3lHrsONf6pvD++azOM
 8HugNF01zR0uZ2Z/JXPL5mZxybYlCBQdmK6QxEB+YcmJizCcnOCsWoEi1XVOGyCC
 /alcvvLa2DceO1lJIo0o7g==
 =3p6h
 -----END PGP SIGNATURE-----

Merge tag 'pwm/for-5.2-rc1' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm

Pull pwm updates from Thierry Reding:
 "Nothing out of the ordinary this cycle.

  The bulk of this is a collection of fixes for existing drivers and
  some cleanups. There's one new driver for i.MX SoCs and addition of
  support for some new variants to existing drivers"

* tag 'pwm/for-5.2-rc1' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm:
  pwm: meson: Add clock source configuration for Meson G12A
  dt-bindings: pwm: Update bindings for the Meson G12A Family
  pwm: samsung: Don't uses devm_*() functions in ->request()
  pwm: Clear chip_data in pwm_put()
  pwm: Add i.MX TPM PWM driver support
  dt-bindings: pwm: Add i.MX TPM PWM binding
  pwm: imx27: Use devm_platform_ioremap_resource() to simplify code
  pwm: meson: Use the spin-lock only to protect register modifications
  pwm: meson: Don't disable PWM when setting duty repeatedly
  pwm: meson: Consider 128 a valid pre-divider
  pwm: sysfs: fix typo "its" -> "it's"
  pwm: tiehrpwm: Enable compilation for ARCH_K3
  dt-bindings: pwm: tiehrpwm: Add TI AM654 SoC specific compatible
  pwm: tiehrpwm: Update shadow register for disabling PWMs
  pwm: img: Turn final 'else if' into 'else' in img_pwm_config
  pwm: Fix deadlock warning when removing PWM device
2019-05-10 12:57:15 -04:00
Linus Torvalds
ea5aee6d97 We have a couple new features and changes in the core clk framework this time
around because we've finally gotten around to fixing some long standing issues.
 There's still work to do though, so this PR is largely laying down the
 foundation for all the driver changes to come in the next merge window.
 
 The first problem we're alleviating is how parents of clks are specified. With
 the new method, we should see lots of drivers migrate away from the current
 design of string comparisons on the entire clk tree to a more direct method
 where they can use clk_hw pointers or more localized names specified in DT or
 via clkdev. This should reduce our reliance on string comparisons for all the
 topology description logic that we've been using for years and hopefully speed
 some things up while avoiding problems we have with generating clk names.
 
 Beyond that we also got rid of the CLK_IS_BASIC flag because it wasn't really
 helping anyone and we introduced big-endian versions of the basic clk types so
 that we can get rid of clk_{readl,writel}(). Both of these are things that
 driver developers have tried to use over the years that I typically bat away
 during code reviews because they're not useful. It's great to see these two
 things go away so maintainers can save time not worrying about these things.
 
 On the driver side we got the usual collection of new SoC support and
 non-critical fixes and updates to existing code. The big topics that stand out
 are the new driver support for Mediatek MT8183 and MT8516 SoCs, Amlogic Meson8b
 and G12a SoCs, and the SiFive FU540 SoC. The other patches in the driver pile
 are mostly fixes for things that are being used for the first time or additions
 for clks that couldn't be tested before because there wasn't a consumer driver
 that exercised them. Details are below and also in the sub-maintainer tags.
 
 Core:
  - Remove clk_readl() and introduce BE versions of basic clk types
  - Rewrite how clk parents can be specified to allow DT/clkdev lookups
  - Removal of the CLK_IS_BASIC clk flag
  - Framework documentation updates and fixes
 
 New Drivers:
  - Support for STM32F769
  - AT91 sam9x60 PMC support
  - SiFive FU540 PRCI and PLL support
  - Qualcomm QCS404 CDSP clk support
  - Qualcomm QCS404 Turing clk support
  - Mediatek MT8183 clock support
  - Mediatek MT8516 clock support
  - Milbeaut M10V clk controller support
  - Support for Cirrus Logic Lochnagar clks
 
 Updates:
  - Rework AT91 sckc DT bindings
  - Fix slow RC oscillator issue on sama5d3
  - Mark UFS clk as critical on Hi-Silicon hi3660 SoCs
  - Various static analysis fixes/finds and const markings
  - Video Engine (ECLK) support on Aspeed SoCs
  - Xilinx ZynqMP Versal platform support
  - Convert Xilinx ZynqMP driver to be struct oriented
  - Fixes for Rockchip rk3328 and rk3288 SoCs
  - Sub-type for Rockchip SoCs where mux and divider aren't a single register
  - Remove SNVS clock from i.MX7UPL clock driver and bindings
  - Improve i.MX5 clock driver for i.MX50 support
  - Addition of ADC clock definition for Exynos 5410 SoC (Odroid XU)
  - Export a new clock for the MBUS controller on the A13
  - Allwinner H6 fixes to support a finer clocking of the video and VPU engines
  - Add g12a support in the Amlogic axg audio clock controller
  - Add missing PCI USB clock on Rensas RZ/N1
  - Add Z2 (Cortex-A53) clocks on Rensas R-Car E3 and RZ/G2E
  - A new helper DIV64_U64_ROUND_CLOSEST() in <linux/math64.h>
  - VPU and Video Decoder clocks on Amlogic Meson8b
  - Finally remove the wrong ABP Meson8b clock id
  - Add Video Decoder, PCIe PLL, and CPU Clocks on Amlogic G12A
  - Re-expose SAR_ADC_SEL and CTS_OSCIN on Amlogic G12A AO clock controller
  - Un-expose some Amlogic AXG-Audio input clocks IDs
 -----BEGIN PGP SIGNATURE-----
 
 iQJFBAABCAAvFiEE9L57QeeUxqYDyoaDrQKIl8bklSUFAlzUabQRHHNib3lkQGtl
 cm5lbC5vcmcACgkQrQKIl8bklSUMmBAAr0WrvWa3s1Ue+lPfmehcAfeI2NkBPC/E
 uhKD+vHBil/Aha33tFTPtVjsZiaMuUETNGPppEUUrHgu4K3UMJZl0iYql6XNVP77
 OObIM5wqXoJ5Yv1e1G0p7X/Qztx7UxEtPwbXJ/9kNN2t6yzg4y8vD2cmXgV5KzHp
 yRUDFNbH9JEyWFbrPhPjD3Bk1PCwdmXNFQg/uYk79g3c84js9MCbWvIqVEuU3vps
 3/9lsDkhbp/flrSOA7D1eloQ6aPXdkLsFzDkJ+6mCA3zxsW/i2N38ZKVDTYG/5rx
 USh3Z0Vyd0f9pKlQqwe1tyr2PBJrYWTtcPBSDcdr4BI1209xseFe4TaqHw1IRKcB
 uYX0gtNTTcgx+8Znvp9y+hE8DhbVNpZvblZuab+rbfb/Gte2wC5/zvzEAz1EqPap
 43VYdi3JR9iWGsC/r4+5OdVFRgWmXFsn5ysQRLkRgE41fKRn7joGHhPS5xDTI0l/
 1rA/8Oh0GMAcSOQ0aSBtavmMCsyJJTjG7s6MpqiO5u/DHnb4MB1Jd0rEWNIjiVmJ
 cqS8II+EbaLWZgt9r3W7ePhkfpHlLw+c4mwI9lRF7Zo67Rz9lrlt1l9YxPnJHewN
 uTRn2ch5W90Jr289wymDNQZGGvCyr+nxKYlSd+kXjlH6poDn6bxYdKHgJexDYmZR
 NVylbizS6lg=
 =/uso
 -----END PGP SIGNATURE-----

Merge tag 'clk-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux

Pull clk framework updates from Stephen Boyd:
 "We have a couple new features and changes in the core clk framework
  this time around because we've finally gotten around to fixing some
  long standing issues. There's still work to do though, so this pull
  request is largely laying down the foundation for all the driver
  changes to come in the next merge window.

  The first problem we're alleviating is how parents of clks are
  specified. With the new method, we should see lots of drivers migrate
  away from the current design of string comparisons on the entire clk
  tree to a more direct method where they can use clk_hw pointers or
  more localized names specified in DT or via clkdev. This should reduce
  our reliance on string comparisons for all the topology description
  logic that we've been using for years and hopefully speed some things
  up while avoiding problems we have with generating clk names.

  Beyond that we also got rid of the CLK_IS_BASIC flag because it wasn't
  really helping anyone and we introduced big-endian versions of the
  basic clk types so that we can get rid of clk_{readl,writel}(). Both
  of these are things that driver developers have tried to use over the
  years that I typically bat away during code reviews because they're
  not useful. It's great to see these two things go away so maintainers
  can save time not worrying about these things.

  On the driver side we got the usual collection of new SoC support and
  non-critical fixes and updates to existing code. The big topics that
  stand out are the new driver support for Mediatek MT8183 and MT8516
  SoCs, Amlogic Meson8b and G12a SoCs, and the SiFive FU540 SoC. The
  other patches in the driver pile are mostly fixes for things that are
  being used for the first time or additions for clks that couldn't be
  tested before because there wasn't a consumer driver that exercised
  them. Details are below and also in the sub-maintainer tags.

  Core:
   - Remove clk_readl() and introduce BE versions of basic clk types
   - Rewrite how clk parents can be specified to allow DT/clkdev lookups
   - Removal of the CLK_IS_BASIC clk flag
   - Framework documentation updates and fixes

  New Drivers:
   - Support for STM32F769
   - AT91 sam9x60 PMC support
   - SiFive FU540 PRCI and PLL support
   - Qualcomm QCS404 CDSP clk support
   - Qualcomm QCS404 Turing clk support
   - Mediatek MT8183 clock support
   - Mediatek MT8516 clock support
   - Milbeaut M10V clk controller support
   - Support for Cirrus Logic Lochnagar clks

  Updates:
   - Rework AT91 sckc DT bindings
   - Fix slow RC oscillator issue on sama5d3
   - Mark UFS clk as critical on Hi-Silicon hi3660 SoCs
   - Various static analysis fixes/finds and const markings
   - Video Engine (ECLK) support on Aspeed SoCs
   - Xilinx ZynqMP Versal platform support
   - Convert Xilinx ZynqMP driver to be struct oriented
   - Fixes for Rockchip rk3328 and rk3288 SoCs
   - Sub-type for Rockchip SoCs where mux and divider aren't a single register
   - Remove SNVS clock from i.MX7UPL clock driver and bindings
   - Improve i.MX5 clock driver for i.MX50 support
   - Addition of ADC clock definition for Exynos 5410 SoC (Odroid XU)
   - Export a new clock for the MBUS controller on the A13
   - Allwinner H6 fixes to support a finer clocking of the video and VPU engines
   - Add g12a support in the Amlogic axg audio clock controller
   - Add missing PCI USB clock on Rensas RZ/N1
   - Add Z2 (Cortex-A53) clocks on Rensas R-Car E3 and RZ/G2E
   - A new helper DIV64_U64_ROUND_CLOSEST() in <linux/math64.h>
   - VPU and Video Decoder clocks on Amlogic Meson8b
   - Finally remove the wrong ABP Meson8b clock id
   - Add Video Decoder, PCIe PLL, and CPU Clocks on Amlogic G12A
   - Re-expose SAR_ADC_SEL and CTS_OSCIN on Amlogic G12A AO clock controller
   - Un-expose some Amlogic AXG-Audio input clocks IDs"

* tag 'clk-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux: (172 commits)
  clk: Cache core in clk_fetch_parent_index() without names
  clk: imx: correct pfdv2 gate_bit/vld_bit operations
  clk: sifive: add a driver for the SiFive FU540 PRCI IP block
  clk: analogbits: add Wide-Range PLL library
  clk: imx: clk-pllv3: mark expected switch fall-throughs
  clk: imx8mq: Add dsi_ipg_div
  clk: imx: pllv4: add fractional-N pll support
  clk: sunxi-ng: Use the correct style for SPDX License Identifier
  clk: sprd: Use the correct style for SPDX License Identifier
  clk: renesas: Use the correct style for SPDX License Identifier
  clk: qcom: Use the correct style for SPDX License Identifier
  clk: davinci: Use the correct style for SPDX License Identifier
  clk: actions: Use the correct style for SPDX License Identifier
  clk: imx: keep uart clock on during system boot
  clk: imx: correct i.MX7D AV PLL num/denom offset
  dt-bindings: clk: add documentation for the SiFive PRCI driver
  clk: stm32mp1: Add ddrperfm clock
  clk: Remove CLK_IS_BASIC clk flag
  clock: milbeaut: Add Milbeaut M10V clock controller
  dt-bindings: clock: milbeaut: add Milbeaut clock description
  ...
2019-05-09 14:50:09 -07:00
Neil Armstrong
f41efceb46 pwm: meson: Add clock source configuration for Meson G12A
For the PWM controller in the Meson G12A SoC, the EE domain and AO domain
have different clock sources. This patch tries to describe them in the
DT compatible data. The two AO PWM controller has different clock source,
but the first AO controller (A & B) can reuse the AXG parents name.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-05-09 17:29:31 +02:00
Uwe Kleine-König
b05232d624 pwm: samsung: Don't uses devm_*() functions in ->request()
A call to ->request() is always paired by a call to ->free() before a
given device is disposed. So the simplification that usually is possible
when using devm_*() functions cannot be used here. So use plain
kzalloc() and kfree() for improved runtime behaviour and reduced memory
footprint.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
[thierry.reding@gmail.com: fix build failure]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-05-09 17:29:15 +02:00
Uwe Kleine-König
e926b12c61 pwm: Clear chip_data in pwm_put()
After a PWM is disposed by its user the per chip data becomes invalid.
Clear the data in common code instead of the device drivers to get
consistent behaviour. Before this patch only three of nine drivers
cleaned up here.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-05-09 17:09:54 +02:00
Anson Huang
738a1cfec2 pwm: Add i.MX TPM PWM driver support
i.MX7ULP has TPM(Low Power Timer/Pulse Width Modulation Module) inside,
it can support multiple PWM channels, all the channels share same
counter and period setting, but each channel can configure its duty and
polarity independently.

There are several TPM modules in i.MX7ULP, the number of channels in TPM
modules are different, it can be read from each TPM module's PARAM
register.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-05-09 17:01:48 +02:00
Anson Huang
1347c94f73 pwm: imx27: Use devm_platform_ioremap_resource() to simplify code
Use the new helper devm_platform_ioremap_resource() which wraps the
platform_get_resource() and devm_ioremap_resource() together, to
simplify the code.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Mukesh Ojha <mojha@codeaurora.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-05-09 16:53:59 +02:00
Martin Blumenstingl
f173747fff pwm: meson: Use the spin-lock only to protect register modifications
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: 211ed63075 ("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>
2019-05-09 16:51:13 +02:00
Bichao Zheng
a279345807 pwm: meson: Don't disable PWM when setting duty repeatedly
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: 211ed63075 ("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>
2019-05-09 16:50:35 +02:00
Martin Blumenstingl
51496e4446 pwm: meson: Consider 128 a valid pre-divider
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: 211ed63075 ("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>
2019-05-09 16:50:04 +02:00
Stephen Boyd
90b6c5c73c clk: Remove CLK_IS_BASIC clk flag
This flag was historically used to indicate that a clk is a "basic" type
of clk like a mux, divider, gate, etc. This never turned out to be very
useful though because it was hard to cleanly split "basic" clks from
other clks in a system. This one flag was a way for type introspection
and it just didn't scale. If anything, it was used by the TI clk driver
to indicate that a clk_hw wasn't contained in the SoC specific clk
structure. We can get rid of this define now that TI is finding those
clks a different way.

Cc: Tero Kristo <t-kristo@ti.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Burton <paul.burton@mips.com>
Cc: James Hogan <jhogan@kernel.org>
Cc: <linux-mips@vger.kernel.org>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Kevin Hilman <khilman@baylibre.com>
Cc: <linux-pwm@vger.kernel.org>
Cc: <linux-amlogic@lists.infradead.org>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
2019-04-26 10:40:49 -07:00
Patrick Havelange
e590eb408c drivers/pwm: pwm-fsl-ftm: use common header for FlexTimer #defines
This also fixes the wrong value for the previously defined
FTM_MODE_INIT macro (it was not used).

Reviewed-by: Esben Haabendal <esben@haabendal.dk>
Signed-off-by: Patrick Havelange <patrick.havelange@essensium.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-04-25 21:33:41 +02:00
Uwe Kleine-König
9ff06679e1 pwm: sysfs: fix typo "its" -> "it's"
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-03-20 12:34:14 +01:00
Vignesh Raghavendra
efc80fb374 pwm: tiehrpwm: Enable compilation for ARCH_K3
K3 devices have the same EHRPWM IP as OMAP SoCs. Enable the driver to be
built for K3 devices. Also, drop reference to AM33xx in help text, as IP
is found on multiple TI SoCs.

Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-03-20 12:33:51 +01:00
Christoph Vogtländer
b00ef53053 pwm: tiehrpwm: Update shadow register for disabling PWMs
It must be made sure that immediate mode is not already set, when
modifying shadow register value in ehrpwm_pwm_disable(). Otherwise
modifications to the action-qualifier continuous S/W force
register(AQSFRC) will be done in the active register.
This may happen when both channels are being disabled. In this case,
only the first channel state will be recorded as disabled in the shadow
register. Later, when enabling the first channel again, the second
channel would be enabled as well. Setting RLDCSF to zero, first, ensures
that the shadow register is updated as desired.

Fixes: 38dabd91ff ("pwm: tiehrpwm: Fix disabling of output of PWMs")
Signed-off-by: Christoph Vogtländer <c.vogtlaender@sigma-surface-science.com>
[vigneshr@ti.com: Improve commit message]
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-03-20 12:31:07 +01:00
Nathan Chancellor
44481955ea pwm: img: Turn final 'else if' into 'else' in img_pwm_config
When building with -Wsometimes-uninitialized, Clang warns:

drivers/pwm/pwm-img.c:126:13: error: variable 'timebase' is used
uninitialized whenever 'if' condition is false
[-Werror,-Wsometimes-uninitialized]

The final else if functions as an else; make that explicit so that Clang
understands that timebase cannot be used uninitialized.

Link: https://github.com/ClangBuiltLinux/linux/issues/400
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-03-20 12:29:22 +01:00
Phong Hoang
347ab94803 pwm: Fix deadlock warning when removing PWM device
This patch fixes deadlock warning if removing PWM device
when CONFIG_PROVE_LOCKING is enabled.

This issue can be reproceduced by the following steps on
the R-Car H3 Salvator-X board if the backlight is disabled:

 # cd /sys/class/pwm/pwmchip0
 # echo 0 > export
 # ls
 device  export  npwm  power  pwm0  subsystem  uevent  unexport
 # cd device/driver
 # ls
 bind  e6e31000.pwm  uevent  unbind
 # echo e6e31000.pwm > unbind

[   87.659974] ======================================================
[   87.666149] WARNING: possible circular locking dependency detected
[   87.672327] 5.0.0 #7 Not tainted
[   87.675549] ------------------------------------------------------
[   87.681723] bash/2986 is trying to acquire lock:
[   87.686337] 000000005ea0e178 (kn->count#58){++++}, at: kernfs_remove_by_name_ns+0x50/0xa0
[   87.694528]
[   87.694528] but task is already holding lock:
[   87.700353] 000000006313b17c (pwm_lock){+.+.}, at: pwmchip_remove+0x28/0x13c
[   87.707405]
[   87.707405] which lock already depends on the new lock.
[   87.707405]
[   87.715574]
[   87.715574] the existing dependency chain (in reverse order) is:
[   87.723048]
[   87.723048] -> #1 (pwm_lock){+.+.}:
[   87.728017]        __mutex_lock+0x70/0x7e4
[   87.732108]        mutex_lock_nested+0x1c/0x24
[   87.736547]        pwm_request_from_chip.part.6+0x34/0x74
[   87.741940]        pwm_request_from_chip+0x20/0x40
[   87.746725]        export_store+0x6c/0x1f4
[   87.750820]        dev_attr_store+0x18/0x28
[   87.754998]        sysfs_kf_write+0x54/0x64
[   87.759175]        kernfs_fop_write+0xe4/0x1e8
[   87.763615]        __vfs_write+0x40/0x184
[   87.767619]        vfs_write+0xa8/0x19c
[   87.771448]        ksys_write+0x58/0xbc
[   87.775278]        __arm64_sys_write+0x18/0x20
[   87.779721]        el0_svc_common+0xd0/0x124
[   87.783986]        el0_svc_compat_handler+0x1c/0x24
[   87.788858]        el0_svc_compat+0x8/0x18
[   87.792947]
[   87.792947] -> #0 (kn->count#58){++++}:
[   87.798260]        lock_acquire+0xc4/0x22c
[   87.802353]        __kernfs_remove+0x258/0x2c4
[   87.806790]        kernfs_remove_by_name_ns+0x50/0xa0
[   87.811836]        remove_files.isra.1+0x38/0x78
[   87.816447]        sysfs_remove_group+0x48/0x98
[   87.820971]        sysfs_remove_groups+0x34/0x4c
[   87.825583]        device_remove_attrs+0x6c/0x7c
[   87.830197]        device_del+0x11c/0x33c
[   87.834201]        device_unregister+0x14/0x2c
[   87.838638]        pwmchip_sysfs_unexport+0x40/0x4c
[   87.843509]        pwmchip_remove+0xf4/0x13c
[   87.847773]        rcar_pwm_remove+0x28/0x34
[   87.852039]        platform_drv_remove+0x24/0x64
[   87.856651]        device_release_driver_internal+0x18c/0x21c
[   87.862391]        device_release_driver+0x14/0x1c
[   87.867175]        unbind_store+0xe0/0x124
[   87.871265]        drv_attr_store+0x20/0x30
[   87.875442]        sysfs_kf_write+0x54/0x64
[   87.879618]        kernfs_fop_write+0xe4/0x1e8
[   87.884055]        __vfs_write+0x40/0x184
[   87.888057]        vfs_write+0xa8/0x19c
[   87.891887]        ksys_write+0x58/0xbc
[   87.895716]        __arm64_sys_write+0x18/0x20
[   87.900154]        el0_svc_common+0xd0/0x124
[   87.904417]        el0_svc_compat_handler+0x1c/0x24
[   87.909289]        el0_svc_compat+0x8/0x18
[   87.913378]
[   87.913378] other info that might help us debug this:
[   87.913378]
[   87.921374]  Possible unsafe locking scenario:
[   87.921374]
[   87.927286]        CPU0                    CPU1
[   87.931808]        ----                    ----
[   87.936331]   lock(pwm_lock);
[   87.939293]                                lock(kn->count#58);
[   87.945120]                                lock(pwm_lock);
[   87.950599]   lock(kn->count#58);
[   87.953908]
[   87.953908]  *** DEADLOCK ***
[   87.953908]
[   87.959821] 4 locks held by bash/2986:
[   87.963563]  #0: 00000000ace7bc30 (sb_writers#6){.+.+}, at: vfs_write+0x188/0x19c
[   87.971044]  #1: 00000000287991b2 (&of->mutex){+.+.}, at: kernfs_fop_write+0xb4/0x1e8
[   87.978872]  #2: 00000000f739d016 (&dev->mutex){....}, at: device_release_driver_internal+0x40/0x21c
[   87.988001]  #3: 000000006313b17c (pwm_lock){+.+.}, at: pwmchip_remove+0x28/0x13c
[   87.995481]
[   87.995481] stack backtrace:
[   87.999836] CPU: 0 PID: 2986 Comm: bash Not tainted 5.0.0 #7
[   88.005489] Hardware name: Renesas Salvator-X board based on r8a7795 ES1.x (DT)
[   88.012791] Call trace:
[   88.015235]  dump_backtrace+0x0/0x190
[   88.018891]  show_stack+0x14/0x1c
[   88.022204]  dump_stack+0xb0/0xec
[   88.025514]  print_circular_bug.isra.32+0x1d0/0x2e0
[   88.030385]  __lock_acquire+0x1318/0x1864
[   88.034388]  lock_acquire+0xc4/0x22c
[   88.037958]  __kernfs_remove+0x258/0x2c4
[   88.041874]  kernfs_remove_by_name_ns+0x50/0xa0
[   88.046398]  remove_files.isra.1+0x38/0x78
[   88.050487]  sysfs_remove_group+0x48/0x98
[   88.054490]  sysfs_remove_groups+0x34/0x4c
[   88.058580]  device_remove_attrs+0x6c/0x7c
[   88.062671]  device_del+0x11c/0x33c
[   88.066154]  device_unregister+0x14/0x2c
[   88.070070]  pwmchip_sysfs_unexport+0x40/0x4c
[   88.074421]  pwmchip_remove+0xf4/0x13c
[   88.078163]  rcar_pwm_remove+0x28/0x34
[   88.081906]  platform_drv_remove+0x24/0x64
[   88.085996]  device_release_driver_internal+0x18c/0x21c
[   88.091215]  device_release_driver+0x14/0x1c
[   88.095478]  unbind_store+0xe0/0x124
[   88.099048]  drv_attr_store+0x20/0x30
[   88.102704]  sysfs_kf_write+0x54/0x64
[   88.106359]  kernfs_fop_write+0xe4/0x1e8
[   88.110275]  __vfs_write+0x40/0x184
[   88.113757]  vfs_write+0xa8/0x19c
[   88.117065]  ksys_write+0x58/0xbc
[   88.120374]  __arm64_sys_write+0x18/0x20
[   88.124291]  el0_svc_common+0xd0/0x124
[   88.128034]  el0_svc_compat_handler+0x1c/0x24
[   88.132384]  el0_svc_compat+0x8/0x18

The sysfs unexport in pwmchip_remove() is completely asymmetric
to what we do in pwmchip_add_with_polarity() and commit 0733424c9b
("pwm: Unexport children before chip removal") is a strong indication
that this was wrong to begin with. We should just move
pwmchip_sysfs_unexport() where it belongs, which is right after
pwmchip_sysfs_unexport_children(). In that case, we do not need
separate functions anymore either.

We also really want to remove sysfs irrespective of whether or not
the chip will be removed as a result of pwmchip_remove(). We can only
assume that the driver will be gone after that, so we shouldn't leave
any dangling sysfs files around.

This warning disappears if we move pwmchip_sysfs_unexport() to
the top of pwmchip_remove(), pwmchip_sysfs_unexport_children().
That way it is also outside of the pwm_lock section, which indeed
doesn't seem to be needed.

Moving the pwmchip_sysfs_export() call outside of that section also
seems fine and it'd be perfectly symmetric with pwmchip_remove() again.

So, this patch fixes them.

Signed-off-by: Phong Hoang <phong.hoang.wz@renesas.com>
[shimoda: revise the commit log and code]
Fixes: 76abbdde2d ("pwm: Add sysfs interface")
Fixes: 0733424c9b ("pwm: Unexport children before chip removal")
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Tested-by: Hoan Nguyen An <na-hoan@jinso.co.jp>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-03-20 12:21:31 +01:00
Thierry Reding
d7d96312fe pwm: atmel: Remove useless symbolic definitions
The values that these symbols define are only assigned to the per-SoC
structure where the context is clear, so there's no need for the extra
symbolic name.

Acked-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-03-04 12:52:49 +01:00
Sheetal Tigadoli
6571d13e44 pwm: bcm-kona: Update macros to remove braces around numbers
Parentheses are not needed around integer literals in macros. Remove
them.

Signed-off-by: Sheetal Tigadoli <sheetal.tigadoli@broadcom.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-03-04 12:52:49 +01:00
Uwe Kleine-König
519ef9b5f2 pwm: imx27: Only enable the clocks once in .get_state()
Currently the function pwm_imx27_get_state() of enables the clocks once
unconditionally at the start, a second time if the PWM is enabled and
disables unconditionally at the end.

Simplify that to enable once at the start and disable conditionally at
the end.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-03-04 12:52:48 +01:00
Yoshihiro Shimoda
b4f9a7268d pwm: rcar: Improve calculation of divider
The rcar_pwm_get_clock_division() has a loop to calculate the divider,
but the value of div should be calculatable without a loop. So, this
patch improves it.

This algorithm is suggested by Uwe Kleine-König and Laurent Pinchart.

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-03-04 12:14:21 +01:00
Yoshihiro Shimoda
8cc2b97039 pwm: rcar: Remove legacy APIs
This patch removes legacy APIs. Since rcar_pwm_{en,dis}able() functions
are reused on "atomic" API, this patch changes the arguments of these
functions. No change in behavior.

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-03-04 12:14:07 +01:00
Yoshihiro Shimoda
87f50ce981 pwm: rcar: Use "atomic" API on rcar_pwm_resume()
To remove legacy API related functions in the future, this patch
uses "atomic" related function instead. No change in behavior.

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-03-04 12:14:06 +01:00
Yoshihiro Shimoda
7f68ce8287 pwm: rcar: Add support "atomic" API
This patch adds support for "atomic" API. This behavior differs with
legacy APIs a little.

 Legacy APIs:
  The PWMCNT register will be updated in rcar_pwm_config() even if
  the PWM state is disabled.

 Atomic API:
  The PWMCNT register will be updated in rcar_pwm_apply() only if
  the PWM state is enabled. Otherwize, if a PWM runs with 30% duty
  cycles and the pwm_apply_state() is called with state->enabled = 0,
  ->duty_cycle = 60 and ->period = 100, this is possible to output
  a 60% duty cycle.

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-03-04 12:14:05 +01:00
Claudiu Beznea
74d0c3b205 pwm: atmel: Add support for SAM9X60's PWM controller
Add support for SAM9X60's PWM controller.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-03-04 11:57:44 +01:00
Claudiu Beznea
abcbe3733e pwm: atmel: Rename objects of type atmel_pwm_data
Rename objects of type atmel_pwm_data to contain chip name instead of
version number.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-03-04 11:56:48 +01:00
Claudiu Beznea
0285827d54 pwm: atmel: Add support for controllers with 32 bit counters
SAM9X60's PWM controller uses 32 bits counters thus it could generate
signals with higher period and duty cycles than the old ones. Prepare
the current driver to be able to work with old controllers (that uses
16 bits counters) and with the new SAM9X60's controller, by providing
counters information based on compatible string.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-03-04 11:56:08 +01:00
Claudiu Beznea
53784159f6 pwm: atmel: Add struct atmel_pwm_data
Add struct atmel_pwm_data to embed different per controller information.
It prepares adding support for another similar controller that needs
additional information. At this stage, embed a member of type struct
atmel_pwm_registers in it.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-03-04 11:50:33 +01:00
Jitao Shi
a87b40615a pwm: Add MediaTek MT8183 display PWM driver support
Use the mtk_pwm_data struction to define different registers
and add MT8183 specific register operations, such as MT8183
doesn't have commit register, needs to disable double buffer
before writing register, and needs to select commit mode
and use PWM_PERIOD/PWM_HIGH_WIDTH.

Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-03-04 11:45:08 +01:00
Mathieu Othacehe
7a58fc5448 pwm: hibvt: Add hi3559v100 support
Add support for the hi3559v100-shub-pwm and hisilicon,hi3559v100-pwm
platforms. They require a special quirk: the PWM has to be enabled twice
to force a duty_cycle refresh.

Signed-off-by: Mathieu Othacehe <m.othacehe@gmail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-03-04 11:38:52 +01:00
Mathieu Othacehe
77c3edde4a pwm: hibvt: Use individual struct per of-data
Split pwm_soc array in one struct per SoC and point to the corresponding
one in of-data.

Signed-off-by: Mathieu Othacehe <m.othacehe@gmail.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-03-04 11:34:24 +01:00
Dan Carpenter
7ca17b2071 pwm: imx: Signedness bug in imx_pwm_get_state()
"ret" only holds zero and negative error codes.  It needs to be signed
for the error handling to work.

Fixes: 9f4c8f9607 ("pwm: imx: Add ipg clock operation")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-01-16 08:45:38 +01:00
Uwe Kleine-König
d80f820690 pwm: imx: Split into two drivers
The two PWM implementations called v1 (for i.MX1 and i.MX21) and v2 (for
i.MX27 and later) have nothing in common apart from needing two clocks
named "per" and "ipg" and being integrated in a SoC named i.MX.

So split the file containing the two disjunct drivers into two files and
two complete separate drivers.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
[thierry.reding@gmail.com: fix a modular build issue]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-01-16 08:45:33 +01:00
Uwe Kleine-König
b9a5c60bc2 pwm: imx: Don't print an error on -EPROBE_DEFER
When getting the peripheral clock fails with -EPROBE_DEFER the driver is
usually probed again later and emitting an error message is irritating.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-01-10 09:40:58 +01:00
Uwe Kleine-König
f20b187e32 pwm: imx: Set driver data earlier simplifying the end of ->probe()
When ->probe() fails the driver core takes care of unsetting the driver
data.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-01-10 09:38:24 +01:00
Uwe Kleine-König
01482d2443 pwm: imx: Remove if block where the condition is always wrong
The ->remove() callback is only called when probe returned successfully.
In this case the driver data cannot be NULL.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-01-10 09:37:40 +01:00
Uwe Kleine-König
cc2d224777 pwm: Drop per-chip dbg_show callback
This callback was introduced in commit 62099abf67 ("pwm: Add debugfs
interface") in 2012 and up to now there is not a single user. So drop
this unused code.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
[thierry.reding@gmail.com: remove kerneldoc for ->dbg_show()]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-01-10 09:34:12 +01:00
Uwe Kleine-König
309b32fb97 pwm: Don't use memcmp() to compare state variables
Given that struct pwm_state is sparse (at least on some platforms),
variables of this type might represent the same state because all fields
are pairwise identical but still memcmp() returns a difference because
some of the unused bits are different.

To prevent surprises compare member by member instead of the whole
occupied memory.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-01-10 09:32:23 +01:00
Anson Huang
9f4c8f9607 pwm: imx: Add ipg clock operation
i.MX PWM module's ipg_clk_s is for PWM register access, on most of i.MX
SoCs, this ipg_clk_s is from system ipg clock or perclk which is always
enabled, but on i.MX7D, the ipg_clk_s is from PWM1_CLK_ROOT which is
controlled by CCGR132, that means the CCGR132 MUST be enabled first
before accessing PWM registers on i.MX7D. This patch adds ipg clock
operation to make sure register access successfully on i.MX7D and it
fixes Linux kernel boot up hang during PWM driver probe.

Fixes: 4a23e6ee9f ("ARM: dts: imx7d-sdb: Restore pwm backlight support")
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2018-12-24 12:06:56 +01:00
Alexander Shiyan
f236d18868 pwm: clps711x: Switch to SPDX identifier
Adopt the SPDX license identifier headers to ease license compliance
management.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2018-12-24 12:06:56 +01:00
Alexander Shiyan
b0f17570b8 pwm: clps711x: Fix period calculation
Commit e39c0df1be ("pwm: Introduce the pwm_args concept") has
changed the variable for the period for clps711x-pwm driver, so now
pwm_get/set_period() works with pwm->state.period variable instead
of pwm->args.period.
This patch changes the period variable in other places where it is used.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2018-12-24 12:06:55 +01:00
Stefan Wahren
e747cbe257 pwm: bcm2835: Switch to SPDX identifier
Adopt the SPDX license identifier headers to ease license compliance
management.

Cc: Bart Tanghe <bart.tanghe@thomasmore.be>
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2018-12-24 12:06:55 +01:00
Clément Péron
88a053d292 pwm: Enable Kona PWM to be built for the Cygnus architecture
The Cygnus architecture uses a Kona PWM. This is already present in the
device tree but can't be built actually. Hence, allow the Kona PWM to
be built for the Cygnus architecture.

Signed-off-by: Clément Péron <peron.clem@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Scott Branden <scott.branden@broadcom.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2018-12-24 12:06:47 +01:00
Michal Vokáč
bf9b0b1b0b pwm: imx: Implement get_state() function for hardware readout
Implement the get_state() function and set the initial state to reflect
real state of the hardware. This allows to keep the PWM running if it was
enabled in bootloader. It is very similar to the GPIO behavior. GPIO pin
set as output in bootloader keep the same setting in Linux unless it is
reconfigured.

If we find the PWM block enabled we need to prepare and enable its source
clock otherwise the clock will be disabled late in the boot as unused.
That will leave the PWM in enabled state but with disabled clock. That has
a side effect that the PWM output is left at its current level at which
the clock was disabled. It is totally non-deterministic and it may be LOW
or HIGH.

Signed-off-by: Michal Vokáč <michal.vokac@ysoft.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2018-12-12 11:52:47 +01:00
Michal Vokáč
9f617ada9f pwm: imx: Use bitops and bitfield macros to define register values
Use existing macros to define register fields instead of manually shifting
the bit masks. Also define some more register bits.

Signed-off-by: Michal Vokáč <michal.vokac@ysoft.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2018-12-12 11:52:32 +01:00
Michal Vokáč
e3adc7efe6 pwm: imx: Sort include files
Sort included header files alphabetically.

Signed-off-by: Michal Vokáč <michal.vokac@ysoft.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2018-12-12 11:51:15 +01:00
Uwe Kleine-König
f82d15e223 pwm: lpc18xx-sct: Don't reconfigure PWM in .request and .free
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>
2018-11-16 11:02:47 +01:00
Hans de Goede
2153bbc12f pwm: lpss: Only set update bit if we are actually changing the settings
According to the datasheet the update bit must be set if the on-time-div
or the base-unit changes.

Now that we properly order device resume on Cherry Trail so that the GFX0
_PS0 method no longer exits with an error, we end up with a sequence of
events where we are writing the same values twice in a row.

First the _PS0 method restores the duty cycle of 0% the GPU driver set
on suspend and then the GPU driver first updates just the enabled bit in
the pwm_state from 0 to 1, causing us to write the same values again,
before restoring the pre-suspend duty-cycle in a separate pwm_apply call.

When writing the update bit the second time, without changing any of
the values the update bit clears immediately / instantly, instead of
staying 1 for a while as usual. After this the next setting of the update
bit seems to be ignored, causing the restoring of the pre-suspend
duty-cycle to not get applied. This makes the backlight come up with
a 0% dutycycle after suspend/resume.

Any further brightness changes after this do work.

This commit moves the setting of the update bit into pwm_lpss_prepare()
and only sets the bit if we have actually changed any of the values.

This avoids the setting of the update bit the second time we configure
the PWM to 0% dutycycle, this fixes the backlight coming up with 0%
duty-cycle after a suspend/resume.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2018-10-16 13:16:15 +02:00
Hans de Goede
4743765bab pwm: lpss: Force runtime-resume on suspend on Cherry Trail
On Cherry Trail devices under Windows the PWM controller used for the
backlight is considered part of the GPU even though it is part of the LPSS
block and thus is an entirely different independent hardware unit.

Because of this on Cherry Trail the GPU's (GFX0 ACPI node) _PS3 and _PS0
methods save and restore the PWM controller registers.

If userspace blanks the screen before suspending, such as e.g. GNOME
does, then the PWM controller will be runtime-suspended when the suspend
starts. This causes the GFX0 _PS? methods to save a value of 0xffffffff
for the PWM control register and to restore this value on resume.

0xffffffff is not a valid value for the register and writing this causes
problems such as e.g. a flickering backlight.

This commit adds a prepare method to the dev_pm_ops and makes it return 0
on Cherry Trail devices forcing a runtime-resume before other device's
suspend methods run. This fixes the reading and writing back of 0xffffffff.

Since we now always runtime-resume the device on suspend, it will be
resumed on resume too and we no longer need to check for the GFX0 _PS0
method having resumed it underneath us, so this commit removes the now no
longer necessary complete dev_pm_op.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2018-10-16 13:15:57 +02:00
Vignesh R
6f37709fb0 pwm: Enable TI ECAP driver for ARCH_K3
K3 devices have the same ECAP IP as OMAP SoCs. Enable driver to be built
for K3 devices. Also, drop reference to AM33xx in help text, as IP is
found on multiple TI SoCs.

Signed-off-by: Vignesh R <vigneshr@ti.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2018-10-16 13:14:52 +02:00