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| author | Clemens Gruber <clemens.gruber@pqgruber.com> | 2015-07-23 17:19:01 +0200 |
|---|---|---|
| committer | Thierry Reding <thierry.reding@gmail.com> | 2015-08-17 16:35:13 +0200 |
| commit | 4a627b52e47ee09348773a981f2097f69ff349ee (patch) | |
| tree | 2e61c4291ef4601efe34e4cbe9f9b52290f3f2d3 | |
| parent | fe0aea7978d25d8df6c128481b8111e76d972657 (diff) | |
| download | linux-stable-4a627b52e47ee09348773a981f2097f69ff349ee.tar.gz linux-stable-4a627b52e47ee09348773a981f2097f69ff349ee.tar.bz2 linux-stable-4a627b52e47ee09348773a981f2097f69ff349ee.zip | |
pwm-pca9685: Fix several driver bugs
Problems:
- When duty_ns == period_ns, the full OFF bit was not cleared and the
PWM output of the PCA9685 stayed off.
- When duty_ns == period_ns and the catch-all channel was used, the
ALL_LED_OFF_L register was not cleared.
- The full ON bit was not cleared when setting the OFF time, therefore
the exact OFF time was ignored when setting a duty_ns < period_ns
Solution: Clear both OFF registers when setting full ON and clear the
full ON bit when changing the OFF registers.
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Signed-off-by: Clemens Gruber <clemens.gruber@pqgruber.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
| -rw-r--r-- | drivers/pwm/pwm-pca9685.c | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/drivers/pwm/pwm-pca9685.c b/drivers/pwm/pwm-pca9685.c index bd5f0276db04..0d17d99b749b 100644 --- a/drivers/pwm/pwm-pca9685.c +++ b/drivers/pwm/pwm-pca9685.c @@ -85,6 +85,22 @@ static int pca9685_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, } if (duty_ns == period_ns) { + /* Clear both OFF registers */ + if (pwm->hwpwm >= PCA9685_MAXCHAN) + reg = PCA9685_ALL_LED_OFF_L; + else + reg = LED_N_OFF_L(pwm->hwpwm); + + regmap_write(pca->regmap, reg, 0x0); + + if (pwm->hwpwm >= PCA9685_MAXCHAN) + reg = PCA9685_ALL_LED_OFF_H; + else + reg = LED_N_OFF_H(pwm->hwpwm); + + regmap_write(pca->regmap, reg, 0x0); + + /* Set the full ON bit */ if (pwm->hwpwm >= PCA9685_MAXCHAN) reg = PCA9685_ALL_LED_ON_H; else @@ -112,6 +128,14 @@ static int pca9685_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, regmap_write(pca->regmap, reg, ((int)duty >> 8) & 0xf); + /* Clear the full ON bit, otherwise the set OFF time has no effect */ + if (pwm->hwpwm >= PCA9685_MAXCHAN) + reg = PCA9685_ALL_LED_ON_H; + else + reg = LED_N_ON_H(pwm->hwpwm); + + regmap_write(pca->regmap, reg, 0); + return 0; } |