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authorSimon Glass <sjg@chromium.org>2021-11-03 22:21:33 +0300
committerMinkyu Kang <mk7.kang@samsung.com>2021-11-09 05:57:22 +0300
commitdfb8470fd0b3b8a87c047b9c1765a1b9123b83b7 (patch)
tree287a938c5af8b07e0a62abd17e6fef8f395b20ec /drivers/pwm
parentf8ed9059001d803b0eae4b49178789aa0e29edec (diff)
downloadu-boot-dfb8470fd0b3b8a87c047b9c1765a1b9123b83b7.tar.xz
exynos: pwm: Deal with a PWM at 100%
At present the counter never hits the comparitor in this case. Add a special case. This ensures that the snow backlight works when at full brightness. Fixes: 76c2ff3e5fd video: backlight: fix pwm's duty cycle calculation Signed-off-by: Simon Glass <sjg@chromium.org> Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>
Diffstat (limited to 'drivers/pwm')
-rw-r--r--drivers/pwm/exynos_pwm.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/pwm/exynos_pwm.c b/drivers/pwm/exynos_pwm.c
index 1afaf784da..609025d680 100644
--- a/drivers/pwm/exynos_pwm.c
+++ b/drivers/pwm/exynos_pwm.c
@@ -43,6 +43,10 @@ static int exynos_pwm_set_config(struct udevice *dev, uint channel,
tcnt = period_ns / rate_ns;
tcmp = duty_ns / rate_ns;
debug("%s: tcnt %u, tcmp %u\n", __func__, tcnt, tcmp);
+
+ /* Ensure that the comparitor will actually hit the target */
+ if (tcmp == tcnt)
+ tcmp = tcnt - 1;
offset = channel * 3;
writel(tcnt, &regs->tcntb0 + offset);
writel(tcmp, &regs->tcmpb0 + offset);