Commit 3962c24f authored by Viorel Suman (OSS)'s avatar Viorel Suman (OSS) Committed by Uwe Kleine-König
Browse files

pwm: imx-tpm: Count the number of enabled channels in probe 



On a soft reset TPM PWM IP may preserve its internal state from previous
runtime, therefore on a subsequent OS boot and driver probe
"enable_count" value and TPM PWM IP internal channels "enabled" states
may get unaligned. In consequence on a suspend/resume cycle the call "if
(--tpm->enable_count == 0)" may lead to "enable_count" overflow the
system being blocked from entering suspend due to:

   if (tpm->enable_count > 0)
       return -EBUSY;

Fix the problem by counting the enabled channels in probe function.

Signed-off-by: default avatarViorel Suman (OSS) <viorel.suman@oss.nxp.com>
Fixes: 738a1cfe ("pwm: Add i.MX TPM PWM driver support")
Link: https://patch.msgid.link/20260311123309.348904-1-viorel.suman@oss.nxp.com


Cc: stable@vger.kernel.org
Signed-off-by: default avatarUwe Kleine-König <ukleinek@kernel.org>
parent 6de23f81

drivers/pwm/pwm-imx-tpm.c

+8 −1
Original line number Diff line number Diff line
@@ -352,7 +352,7 @@ static int pwm_imx_tpm_probe(struct platform_device *pdev) 
	struct clk *clk;

	void __iomem *base;

	int ret;

	unsigned int npwm;

	unsigned int i, npwm;

	u32 val;



	base = devm_platform_ioremap_resource(pdev, 0);
@@ -382,6 +382,13 @@ static int pwm_imx_tpm_probe(struct platform_device *pdev) 


	mutex_init(&tpm->lock);



	/* count the enabled channels */

	for (i = 0; i < npwm; ++i) {

		val = readl(base + PWM_IMX_TPM_CnSC(i));

		if (FIELD_GET(PWM_IMX_TPM_CnSC_ELS, val))

			++tpm->enable_count;

	}



	ret = devm_pwmchip_add(&pdev->dev, chip);

	if (ret)

		return dev_err_probe(&pdev->dev, ret, "failed to add PWM chip\n");