linux-toradex.git/drivers/pwm, branch v5.11-rc3

Merge tag 'pwm/for-5.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm

2020-12-19T19:51:32+00:00

Pull pwm updates from Thierry Reding:
 "This is a fairly big release cycle from the PWM framework's point of
  view.

  There's a large patcheset here which converts drivers to use the new
  devm_platform_ioremap_resource() helper and a bunch of minor fixes to
  existing drivers. Some of the existing drivers also add support for
  more hardware, such as Atmel SAMA 5D2 and Mediatek MT8183.

  Finally there's a couple of new drivers for Intel Keem Bay and LGM
  SoCs as well as the DesignWare PWM controller"

* tag 'pwm/for-5.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm: (66 commits)
  pwm: sun4i: Remove erroneous else branch
  pwm: sl28cpld: Set driver data before registering the PWM chip
  pwm: Remove unused function pwmchip_add_inversed()
  pwm: imx27: Fix overflow for bigger periods
  pwm: bcm2835: Support apply function for atomic configuration
  pwm: keembay: Fix build failure with -Os
  pwm: core: Use octal permission
  pwm: lpss: Make compilable with COMPILE_TEST
  pwm: Fix dependencies on HAS_IOMEM
  pwm: Use -EINVAL for unsupported polarity
  pwm: sti: Remove unnecessary blank line
  pwm: sti: Avoid conditional gotos
  pwm: Add PWM fan controller driver for LGM SoC
  Add DT bindings YAML schema for PWM fan controller of LGM SoC
  pwm: Add DesignWare PWM Controller Driver
  dt-bindings: pwm: mtk-disp: add MT8167 SoC binding
  pwm: mediatek: Add MT8183 SoC support
  pwm: mediatek: Always use bus clock
  dt-bindings: pwm: pwm-mediatek: Add documentation for MT8183 SoC
  pwm: Add PWM driver for Intel Keem Bay
  ...

pwm: sun4i: Remove erroneous else branch

2020-12-17T13:23:49+00:00

Commit d3817a647059 ("pwm: sun4i: Remove redundant needs_delay") changed
the logic of an else branch so that the PWM_EN and PWM_CLK_GATING bits
are now cleared if the PWM is to be disabled, whereas previously the
condition was always false, and hence the branch never got executed.

This code is reported causing backlight issues on boards based on the
Allwinner A20 SoC. Fix this by removing the else branch, which restores
the behaviour prior to the offending commit.

Note that the PWM_EN and PWM_CLK_GATING bits still get cleared later in
sun4i_pwm_apply() if the PWM is to be disabled.

Fixes: d3817a647059 ("pwm: sun4i: Remove redundant needs_delay")
Reported-by: Taras Galchenko 
Suggested-by: Taras Galchenko 
Tested-by: Taras Galchenko 
Reviewed-by: Uwe Kleine-König 
Signed-off-by: Thierry Reding

pwm: sl28cpld: Set driver data before registering the PWM chip

2020-12-17T13:19:02+00:00

It is good practice to set the driver data before registering a device
with a subsystem because the subsystem or the driver core may call back
into the driver implementation. This is not currently an issue, but to
prevent future changes from causing this to break unexpectedly, make
sure that the driver data is set before the PWM chip registration.

Signed-off-by: Thierry Reding

pwm: imx27: Fix overflow for bigger periods

2020-12-17T13:19:01+00:00

The second parameter of do_div is an u32 and NSEC_PER_SEC * prescale
overflows this for bigger periods. Assuming the usual pwm input clk rate
of 66 MHz this happens starting at requested period > 606060 ns.

Splitting the division into two operations doesn't loose any precision.
It doesn't need to be feared that c / NSEC_PER_SEC doesn't fit into the
unsigned long variable "duty_cycles" because in this case the assignment
above to period_cycles would already have been overflowing as
period >= duty_cycle and then the calculation is moot anyhow.

Fixes: aef1a3799b5c ("pwm: imx27: Fix rounding behavior")
Signed-off-by: Uwe Kleine-König 
Tested-by: Johannes Pointner 
Signed-off-by: Thierry Reding

pwm: bcm2835: Support apply function for atomic configuration

2020-12-17T13:19:01+00:00

Use the newer .apply function of pwm_ops instead of .config, .enable,
.disable and .set_polarity. This guarantees atomic changes of the pwm
controller configuration. It also reduces the size of the driver.

Since now period is a 64 bit value, add an extra check to reject periods
that exceed the possible max value for the 32 bit register.

This has been tested on a Raspberry PI 4.

Signed-off-by: Lino Sanfilippo 
Reviewed-by: Uwe Kleine-König 
Signed-off-by: Thierry Reding

pwm: keembay: Fix build failure with -Os

2020-12-17T13:19:00+00:00

The driver used this construct:

	#define KMB_PWM_LEADIN_MASK             GENMASK(30, 0)

	static inline void keembay_pwm_update_bits(struct keembay_pwm *priv, u32 mask,
						   u32 val, u32 offset)
	{
		u32 buff = readl(priv->base + offset);

		buff = u32_replace_bits(buff, val, mask);
		writel(buff, priv->base + offset);
	}

	...
	keembay_pwm_update_bits(priv, KMB_PWM_LEADIN_MASK, 0,
					KMB_PWM_LEADIN_OFFSET(pwm->hwpwm));

With CONFIG_CC_OPTIMIZE_FOR_SIZE the compiler (here: gcc 10.2.0) this
triggers:

	In file included from /home/uwe/gsrc/linux/drivers/pwm/pwm-keembay.c:16:
	In function ‘field_multiplier’,
	    inlined from ‘keembay_pwm_update_bits’ at /home/uwe/gsrc/linux/include/linux/bitfield.h:124:17:
	/home/uwe/gsrc/linux/include/linux/bitfield.h:119:3: error: call to ‘__bad_mask’ declared with attribute error: bad bitfield mask
	  119 |   __bad_mask();
	      |   ^~~~~~~~~~~~
	In function ‘field_multiplier’,
	    inlined from ‘keembay_pwm_update_bits’ at /home/uwe/gsrc/linux/include/linux/bitfield.h:154:1:
	/home/uwe/gsrc/linux/include/linux/bitfield.h:119:3: error: call to ‘__bad_mask’ declared with attribute error: bad bitfield mask
	  119 |   __bad_mask();
	      |   ^~~~~~~~~~~~

The compiler doesn't seem to be able to notice that with field being
0x3ffffff the expression

	if ((field | (field - 1)) & ((field | (field - 1)) + 1))
		__bad_mask();

can be optimized away.

So use __always_inline and document the problem in a comment to fix
this.

Reported-by: kernel test robot 
Signed-off-by: Uwe Kleine-König 
Tested-by: Vijayakannan Ayyathurai 
Signed-off-by: Thierry Reding

pwm: core: Use octal permission

2020-12-17T13:19:00+00:00

Permission bits are easier readable in octal than with using the
symbolic names.

Fixes the following warning generated by checkpatch:

    WARNING: Symbolic permissions 'S_IRUGO' are not preferred. Consider using octal permissions '0444'.
    #1341: FILE: drivers/pwm/core.c:1341:
    +       debugfs_create_file("pwm", S_IFREG | S_IRUGO, NULL, NULL,

Signed-off-by: Soham Biswas 
Acked-by: Uwe Kleine-König 
Signed-off-by: Thierry Reding

pwm: lpss: Make compilable with COMPILE_TEST

2020-12-17T13:19:00+00:00

All used ACPI functions have dummy implementations, and there is no hard
dependency on x86.

Signed-off-by: Uwe Kleine-König 
Signed-off-by: Thierry Reding

pwm: Fix dependencies on HAS_IOMEM

2020-12-17T13:19:00+00:00

Drivers making use of IO remapping must depend on HAS_IOMEM.

Reported-by: kernel test robot 
Signed-off-by: Uwe Kleine-König 
Signed-off-by: Thierry Reding

pwm: Use -EINVAL for unsupported polarity

2020-12-17T13:18:59+00:00

Instead of using a mix of -EOPNOTSUPP and -ENOTSUPP, use the more
standard -EINVAL to signal that the specified polarity value was
invalid.

Acked-by: Uwe Kleine-König 
Acked-by: Lee Jones 
Signed-off-by: Thierry Reding