After commit a020f22a4ff5 ("pwm: jz4740: Make PWM start with the active part"), the trick to set duty > period to properly shut down TCU2 channels did not work anymore, because of the polarity inversion.
Address this issue by restoring the proper polarity before disabling the channels.
Fixes: a020f22a4ff5 ("pwm: jz4740: Make PWM start with the active part") Signed-off-by: Paul Cercueil paul@crapouillou.net Cc: stable@vger.kernel.org --- drivers/pwm/pwm-jz4740.c | 62 ++++++++++++++++++++++++++-------------- 1 file changed, 40 insertions(+), 22 deletions(-)
diff --git a/drivers/pwm/pwm-jz4740.c b/drivers/pwm/pwm-jz4740.c index 228eb104bf1e..65462a0052af 100644 --- a/drivers/pwm/pwm-jz4740.c +++ b/drivers/pwm/pwm-jz4740.c @@ -97,6 +97,19 @@ static int jz4740_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) return 0; }
+static void jz4740_pwm_set_polarity(struct jz4740_pwm_chip *jz, + unsigned int hwpwm, + enum pwm_polarity polarity) +{ + unsigned int value = 0; + + if (polarity == PWM_POLARITY_INVERSED) + value = TCU_TCSR_PWM_INITL_HIGH; + + regmap_update_bits(jz->map, TCU_REG_TCSRc(hwpwm), + TCU_TCSR_PWM_INITL_HIGH, value); +} + static void jz4740_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) { struct jz4740_pwm_chip *jz = to_jz4740(chip); @@ -130,6 +143,7 @@ static int jz4740_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, unsigned long long tmp = 0xffffull * NSEC_PER_SEC; struct clk *clk = pwm_get_chip_data(pwm); unsigned long period, duty; + enum pwm_polarity polarity; long rate; int err;
@@ -169,6 +183,9 @@ static int jz4740_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, if (duty >= period) duty = period - 1;
+ /* Restore regular polarity before disabling the channel. */ + jz4740_pwm_set_polarity(jz4740, pwm->hwpwm, state->polarity); + jz4740_pwm_disable(chip, pwm);
err = clk_set_rate(clk, rate); @@ -190,29 +207,30 @@ static int jz4740_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, regmap_update_bits(jz4740->map, TCU_REG_TCSRc(pwm->hwpwm), TCU_TCSR_PWM_SD, TCU_TCSR_PWM_SD);
- /* - * Set polarity. - * - * The PWM starts in inactive state until the internal timer reaches the - * duty value, then becomes active until the timer reaches the period - * value. In theory, we should then use (period - duty) as the real duty - * value, as a high duty value would otherwise result in the PWM pin - * being inactive most of the time. - * - * Here, we don't do that, and instead invert the polarity of the PWM - * when it is active. This trick makes the PWM start with its active - * state instead of its inactive state. - */ - if ((state->polarity == PWM_POLARITY_NORMAL) ^ state->enabled) - regmap_update_bits(jz4740->map, TCU_REG_TCSRc(pwm->hwpwm), - TCU_TCSR_PWM_INITL_HIGH, 0); - else - regmap_update_bits(jz4740->map, TCU_REG_TCSRc(pwm->hwpwm), - TCU_TCSR_PWM_INITL_HIGH, - TCU_TCSR_PWM_INITL_HIGH); - - if (state->enabled) + if (state->enabled) { + /* + * Set polarity. + * + * The PWM starts in inactive state until the internal timer + * reaches the duty value, then becomes active until the timer + * reaches the period value. In theory, we should then use + * (period - duty) as the real duty value, as a high duty value + * would otherwise result in the PWM pin being inactive most of + * the time. + * + * Here, we don't do that, and instead invert the polarity of + * the PWM when it is active. This trick makes the PWM start + * with its active state instead of its inactive state. + */ + if (state->polarity == PWM_POLARITY_NORMAL) + polarity = PWM_POLARITY_INVERSED; + else + polarity = PWM_POLARITY_NORMAL; + + jz4740_pwm_set_polarity(jz4740, pwm->hwpwm, polarity); + jz4740_pwm_enable(chip, pwm); + }
return 0; }