[PATCH] pwm: imx-tpm: force 'real_period' to be zero in suspend

* [PATCH] pwm: imx-tpm: force 'real_period' to be zero in suspend
@ 2023-05-05  6:58 Clark Wang
  2023-06-14  8:59 ` Uwe Kleine-König
  2023-06-23 14:51 ` Thierry Reding
  0 siblings, 2 replies; 3+ messages in thread
From: Clark Wang @ 2023-05-05  6:58 UTC (permalink / raw)
  To: thierry.reding, u.kleine-koenig, shawnguo, s.hauer, festevam
  Cc: kernel, linux-imx, linux-pwm, linux-arm-kernel, linux-kernel

From: Fancy Fang <chen.fang@nxp.com>

During suspend, all the tpm registers will lose values.
So the 'real_period' value of struct 'imx_tpm_pwm_chip'
should be forced to be zero to force the period update
code can be executed after system resume back.

Signed-off-by: Fancy Fang <chen.fang@nxp.com>
Signed-off-by: Clark Wang <xiaoning.wang@nxp.com>
---
 drivers/pwm/pwm-imx-tpm.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/pwm/pwm-imx-tpm.c b/drivers/pwm/pwm-imx-tpm.c
index 5e2b452ee5f2..98ab65c89685 100644
--- a/drivers/pwm/pwm-imx-tpm.c
+++ b/drivers/pwm/pwm-imx-tpm.c
@@ -397,6 +397,13 @@ static int __maybe_unused pwm_imx_tpm_suspend(struct device *dev)
 	if (tpm->enable_count > 0)
 		return -EBUSY;
 
+	/*
+	 * Force 'real_period' to be zero to force period update code
+	 * can be executed after system resume back, since suspend causes
+	 * the period related registers to become their reset values.
+	 */
+	tpm->real_period = 0;
+
 	clk_disable_unprepare(tpm->clk);
 
 	return 0;
-- 
2.34.1


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