Hans de Goede de01ce3e40 pwm: lpss: Add range limit check for the base_unit register value ... [ Upstream commit ef9f60daab ] When the user requests a high enough period ns value, then the calculations in pwm_lpss_prepare() might result in a base_unit value of 0. But 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. Adding 0 to the counter is a no-op. The data-sheet even explicitly states that writing 0 to the base_unit bits will result in the PWM outputting a continuous 0 signal. When the user requestes a low enough period ns value, then the calculations in pwm_lpss_prepare() might result in a base_unit value which is bigger then base_unit_range - 1. Currently the codes for this deals with this by applying a mask: base_unit &= (base_unit_range - 1); But this means that we let the value overflow the range, we throw away the higher bits and store whatever value is left in the lower bits into the register leading to a random output frequency, rather then clamping the output frequency to the highest frequency which the hardware can do. This commit fixes both issues by clamping the base_unit value to be between 1 and (base_unit_range - 1). Fixes: 684309e504 ("pwm: lpss: Avoid potential overflow of base_unit") Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Acked-by: Thierry Reding <thierry.reding@gmail.com> Signed-off-by: Hans de Goede <hdegoede@redhat.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200903112337.4113-5-hdegoede@redhat.com Signed-off-by: Sasha Levin <sashal@kernel.org>		2020-10-29 09:07:05 +01:00
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core.c	pwm: Clear chip_data in pwm_put()	2019-12-05 15:38:12 +01:00
Kconfig
Makefile
pwm-ab8500.c
pwm-atmel-hlcdc.c
pwm-atmel-tcb.c
pwm-atmel.c
pwm-bcm-iproc.c	pwm: bcm-iproc: handle clk_get_rate() return	2020-08-21 09:48:21 +02:00
pwm-bcm-kona.c
pwm-bcm2835.c	pwm: bcm2835: Dynamically allocate base	2020-05-02 17:24:15 +02:00
pwm-berlin.c	pwm: Clear chip_data in pwm_put()	2019-12-05 15:38:12 +01:00
pwm-bfin.c
pwm-brcmstb.c
pwm-clps711x.c	pwm: clps711x: Fix period calculation	2019-12-05 15:37:48 +01:00
pwm-crc.c
pwm-cros-ec.c
pwm-ep93xx.c
pwm-fsl-ftm.c
pwm-hibvt.c
pwm-img.c
pwm-imx.c
pwm-jz4740.c
pwm-lp3943.c
pwm-lpc18xx-sct.c
pwm-lpc32xx.c
pwm-lpss-pci.c
pwm-lpss-platform.c
pwm-lpss.c	pwm: lpss: Add range limit check for the base_unit register value	2020-10-29 09:07:05 +01:00
pwm-lpss.h
pwm-mediatek.c
pwm-meson.c	pwm: meson: Don't disable PWM when setting duty repeatedly	2020-01-27 14:46:34 +01:00
pwm-mtk-disp.c
pwm-mxs.c
pwm-omap-dmtimer.c	pwm: omap-dmtimer: Remove PWM chip in .remove before making it unfunctional	2020-02-28 16:36:05 +01:00
pwm-pca9685.c	pwm: pca9685: Fix PWM/GPIO inter-operation	2020-04-24 08:00:55 +02:00
pwm-puv3.c
pwm-pxa.c
pwm-rcar.c	pwm: rcar: Fix late Runtime PM enablement	2020-05-02 17:24:13 +02:00
pwm-renesas-tpu.c	pwm: renesas-tpu: Fix late Runtime PM enablement	2020-05-02 17:24:15 +02:00
pwm-rockchip.c
pwm-samsung.c	pwm: Clear chip_data in pwm_put()	2019-12-05 15:38:12 +01:00
pwm-spear.c
pwm-sti.c
pwm-stm32-lp.c	pwm: stm32-lp: Add check in case requested period cannot be achieved	2019-10-11 18:18:40 +02:00
pwm-stm32.c
pwm-stmpe.c
pwm-sun4i.c
pwm-tegra.c
pwm-tiecap.c
pwm-tiehrpwm.c
pwm-tipwmss.c
pwm-twl-led.c
pwm-twl.c
pwm-vt8500.c
pwm-zx.c
sysfs.c	pwm: Fix deadlock warning when removing PWM device	2019-06-15 11:54:59 +02:00