Merge tag 'pwm/for-6.17-rc1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/ukleinek/linux

Pull pwm fixes from Uwe Kleine-König:
 "Two fixes for the mediatek and the imx-tpm driver. Both are old
  (v4.12-rc1 and v5.2-rc1 respectively).

  The mediatek issue is that both period and duty_cycle were configured
  to higher values than requested. For most applications the period part
  is no tragedy, but a PWM that is configured for duty_cycle = 0 should
  really emit a constant inactive signal. That was noticed by an LED not
  being completely off in this case (two commits for one fix: a
  preparatory one and the actual fix in the second one).

  For the imx-tpm PWM driver the fixed issue is that the first period is
  quite a bit too long under some circumstances. So it might take up to
  UINT32_MAX << 7 clock ticks until the PWM starts toggling. With an
  assumed input clock rate of 166 MHz (completely made up) that's 55
  minutes"

* tag 'pwm/for-6.17-rc1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/ukleinek/linux:
  pwm: imx-tpm: Reset counter if CMOD is 0
  pwm: mediatek: Fix duty and period setting
  pwm: mediatek: Handle hardware enable and clock enable separately

1 files changed, 9 insertions, 0 deletions

diff --git a/drivers/pwm/pwm-imx-tpm.c b/drivers/pwm/pwm-imx-tpm.c
index 7ee7b65b9b90..5b399de16d60 100644
--- a/drivers/pwm/pwm-imx-tpm.c
+++ b/drivers/pwm/pwm-imx-tpm.c
@@ -205,6 +205,15 @@ static int pwm_imx_tpm_apply_hw(struct pwm_chip *chip,
 		writel(val, tpm->base + PWM_IMX_TPM_SC);
 
 		/*
+		 * if the counter is disabled (CMOD == 0), programming the new
+		 * period length (MOD) will not reset the counter (CNT). If
+		 * CNT.COUNT happens to be bigger than the new MOD value then
+		 * the counter will end up being reset way too late. Therefore,
+		 * manually reset it to 0.
+		 */
+		if (!cmod)
+			writel(0x0, tpm->base + PWM_IMX_TPM_CNT);
+		/*
 		 * set period count:
 		 * if the PWM is disabled (CMOD[1:0] = 2b00), then MOD register
 		 * is updated when MOD register is written.