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pwm: renesas-tpu: Fix runtime PM reference leak

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tpu_pwm_timer_start() used pm_runtime_get_sync() without checking its
return value before touching the TPU clock.  A failed runtime resume was
therefore ignored, and the callback continued into register access.

Use pm_runtime_resume_and_get() and propagate a failed resume.  Keep the
matching put when clock preparation fails after a successful resume.

tpu_pwm_disable() also needs to propagate a failed start so that the PWM
apply callback does not access registers while runtime PM is inactive.

This issue was found by a static analysis checker and confirmed by manual
source review.

Fixes: 99b82abb0a ("pwm: Add Renesas TPU PWM driver")
Signed-off-by: Ruoyu Wang <ruoyuw560@gmail.com>
Link: https://patch.msgid.link/20260814134143.1388120-1-ruoyuw560@gmail.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
This commit is contained in:
Ruoyu Wang 2026-08-14 21:41:43 +08:00 committed by Uwe Kleine-König
parent cee9395acd
commit 62cff15fbf
1 changed files with 18 additions and 5 deletions
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23
drivers/pwm/pwm-renesas-tpu.c
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@ -149,10 +149,14 @@ static int tpu_pwm_timer_start(struct tpu_pwm_device *tpd)
if (!tpd->timer_on) {
/* Wake up device and enable clock. */
pm_runtime_get_sync(&tpd->tpu->pdev->dev);
ret = pm_runtime_resume_and_get(&tpd->tpu->pdev->dev);
if (ret < 0)
return ret;
ret = clk_prepare_enable(tpd->tpu->clk);
if (ret) {
dev_err(&tpd->tpu->pdev->dev, "cannot enable clock\n");
pm_runtime_put(&tpd->tpu->pdev->dev);
return ret;
}
tpd->timer_on = true;
@ -382,15 +386,21 @@ static int tpu_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
return 0;
}
static void tpu_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
static int tpu_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct tpu_device *tpu = to_tpu_device(chip);
struct tpu_pwm_device *tpd = &tpu->tpd[pwm->hwpwm];
int ret;
/* The timer must be running to modify the pin output configuration. */
tpu_pwm_timer_start(tpd);
ret = tpu_pwm_timer_start(tpd);
if (ret < 0)
return ret;
tpu_pwm_set_pin(tpd, TPU_PIN_INACTIVE);
tpu_pwm_timer_stop(tpd);
return 0;
}
static int tpu_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
@ -401,7 +411,10 @@ static int tpu_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
if (state->polarity != pwm->state.polarity) {
if (enabled) {
tpu_pwm_disable(chip, pwm);
err = tpu_pwm_disable(chip, pwm);
if (err)
return err;
enabled = false;
}
@ -412,7 +425,7 @@ static int tpu_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
if (!state->enabled) {
if (enabled)
tpu_pwm_disable(chip, pwm);
return tpu_pwm_disable(chip, pwm);
return 0;
}