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181f4d2f44
linux/drivers/pwm
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Hans de Goede 181f4d2f44 pwm: lpss: Fix off by one error in base_unit math in pwm_lpss_prepare() 
According to the data-sheet the way the PWM controller works is that
each input clock-cycle the base_unit gets added to a N bit counter and
that counter overflowing determines the PWM output frequency.

So assuming e.g. a 16 bit counter this means that if base_unit is set to 1,
after 65535 input clock-cycles the counter has been increased from 0 to
65535 and it will overflow on the next cycle, so it will overflow after
every 65536 clock cycles and thus the calculations done in
pwm_lpss_prepare() should use 65536 and not 65535.

This commit fixes this. Note this also aligns the calculations in
pwm_lpss_prepare() with those in pwm_lpss_get_state().

Note this effectively reverts commit 684309e504 ("pwm: lpss: Avoid
potential overflow of base_unit"). The next patch in this series really
fixes the potential overflow of the base_unit value.

Fixes: 684309e504 ("pwm: lpss: Avoid potential overflow of base_unit")
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200903112337.4113-4-hdegoede@redhat.com
2020-09-06 15:37:58 +02:00
..
core.c pwm: Add missing "CONFIG_" prefix 2020-06-04 19:09:28 +02:00
Kconfig pwm: jz4740: Drop dependency on MACH_INGENIC 2020-06-02 14:23:42 +02:00
Makefile pwm: Add support for Azoteq IQS620A PWM generator 2020-04-14 16:02:28 +02:00
pwm-ab8500.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 194 2019-05-30 11:29:22 -07:00
pwm-atmel-hlcdc.c pwm: Ensure pwm_apply_state() doesn't modify the state argument 2019-09-21 03:25:10 +02:00
pwm-atmel-tcb.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 194 2019-05-30 11:29:22 -07:00
pwm-atmel.c pwm: atmel: Implement .get_state() 2020-01-08 13:47:46 +01:00
pwm-bcm2835.c pwm: bcm2835: Dynamically allocate base 2020-03-30 16:55:25 +02:00
pwm-bcm-iproc.c pwm: bcm-iproc: Prevent unloading the driver module while in use 2019-11-08 18:38:06 +01:00
pwm-bcm-kona.c pwm: bcm-kona: Update macros to remove braces around numbers 2019-03-04 12:52:49 +01:00
pwm-berlin.c pwm: Clear chip_data in pwm_put() 2019-05-09 17:09:54 +02:00
pwm-brcmstb.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157 2019-05-30 11:26:37 -07:00
pwm-clps711x.c pwm: clps711x: Switch to SPDX identifier 2018-12-24 12:06:56 +01:00
pwm-crc.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 174 2019-05-30 11:26:41 -07:00
pwm-cros-ec.c pwm: cros-ec: Cache duty cycle value 2019-12-09 10:05:42 +01:00
pwm-ep93xx.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157 2019-05-30 11:26:37 -07:00
pwm-fsl-ftm.c pwm: Ensure pwm_apply_state() doesn't modify the state argument 2019-09-21 03:25:10 +02:00
pwm-hibvt.c pwm: Ensure pwm_apply_state() doesn't modify the state argument 2019-09-21 03:25:10 +02:00
pwm-img.c pwm: img: Call pm_runtime_put() in pm_runtime_get_sync() failed case 2020-06-02 15:50:51 +02:00
pwm-imx1.c pwm: imx: Split into two drivers 2019-01-16 08:45:33 +01:00
pwm-imx27.c pwm: imx27: Fix rounding behavior 2020-06-02 15:50:52 +02:00
pwm-imx-tpm.c pwm: imx-tpm: Remove unused includes 2020-03-30 16:55:26 +02:00
pwm-iqs620a.c pwm: Add support for Azoteq IQS620A PWM generator 2020-04-14 16:02:28 +02:00
pwm-jz4740.c pwm: jz4740: Add support for the JZ4725B 2020-06-02 14:24:57 +02:00
pwm-lp3943.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 372 2019-06-05 17:37:10 +02:00
pwm-lpc18xx-sct.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 178 2019-05-30 11:29:19 -07:00
pwm-lpc32xx.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 372 2019-06-05 17:37:10 +02:00
pwm-lpss-pci.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
pwm-lpss-platform.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
pwm-lpss.c pwm: lpss: Fix off by one error in base_unit math in pwm_lpss_prepare() 2020-09-06 15:37:58 +02:00
pwm-lpss.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
pwm-mediatek.c pwm: mediatek: Add MT7629 compatible string 2019-09-26 13:27:50 +02:00
pwm-meson.c pwm: meson: Remove redundant assignment to variable fin_freq 2020-04-03 21:40:56 +02:00
pwm-mtk-disp.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 174 2019-05-30 11:26:41 -07:00
pwm-mxs.c pwm: mxs: Remove unused include of of_address.h 2020-03-30 16:55:27 +02:00
pwm-omap-dmtimer.c pwm: omap-dmtimer: Implement .apply callback 2020-03-30 18:03:08 +02:00
pwm-pca9685.c pwm: pca9685: Fix PWM/GPIO inter-operation 2020-04-03 21:41:42 +02:00
pwm-puv3.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
pwm-pxa.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
pwm-rcar.c pwm: rcar: Fix late Runtime PM enablement 2020-03-30 18:03:05 +02:00
pwm-renesas-tpu.c pwm: renesas-tpu: Drop confusing registered message 2020-03-30 18:03:06 +02:00
pwm-rockchip.c pwm: rockchip: Simplify rockchip_pwm_get_state() 2020-06-02 15:50:52 +02:00
pwm-samsung.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 178 2019-05-30 11:29:19 -07:00
pwm-sifive.c pwm: Ensure pwm_apply_state() doesn't modify the state argument 2019-09-21 03:25:10 +02:00
pwm-spear.c pwm: drop owner assignment from platform_drivers 2014-10-20 16:21:28 +02:00
pwm-sprd.c pwm: Ensure pwm_apply_state() doesn't modify the state argument 2019-09-21 03:25:10 +02:00
pwm-sti.c pwm: Remove dev_err() usage after platform_get_irq() 2019-09-21 00:58:35 +02:00
pwm-stm32-lp.c pwm: stm32-lp: Add check in case requested period cannot be achieved 2019-09-21 03:25:10 +02:00
pwm-stm32.c pwm: stm32: Remove automatic output enable 2020-01-20 13:47:36 +01:00
pwm-stmpe.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
pwm-sun4i.c pwm: sun4i: Support direct clock output on Allwinner A64 2020-06-02 14:20:11 +02:00
pwm-tegra.c pwm: tegra: Support dynamic clock frequency configuration 2020-06-02 14:25:37 +02:00
pwm-tiecap.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 61 2019-05-24 17:36:45 +02:00
pwm-tiehrpwm.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 61 2019-05-24 17:36:45 +02:00
pwm-twl-led.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234 2019-06-19 17:09:07 +02:00
pwm-twl.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234 2019-06-19 17:09:07 +02:00
pwm-vt8500.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 282 2019-06-05 17:36:37 +02:00
pwm-zx.c pwm: Ensure pwm_apply_state() doesn't modify the state argument 2019-09-21 03:25:10 +02:00
sysfs.c pwm: Changes for v5.3-rc1 2019-07-09 08:57:45 -07:00