pwm: lpc32xx: Don't modify HW state in .probe() after the PWM chip was registered
authorUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Wed, 7 Jul 2021 16:27:49 +0000 (18:27 +0200)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Sun, 26 Sep 2021 11:37:29 +0000 (13:37 +0200)
commitbb4de81eb940e7027f37a6fd3b7ddcb4403deb56
treeddcd27e0d50a08522aa314f38e8eb359ef6263da
parent360f114624b1dcb3895c1ad41c442b3e4450f925
pwm: lpc32xx: Don't modify HW state in .probe() after the PWM chip was registered

commit 3d2813fb17e5fd0d73c1d1442ca0192bde4af10e upstream.

This fixes a race condition: After pwmchip_add() is called there might
already be a consumer and then modifying the hardware behind the
consumer's back is bad. So set the default before.

(Side-note: I don't know what this register setting actually does, if
this modifies the polarity there is an inconsistency because the
inversed polarity isn't considered if the PWM is already running during
.probe().)

Fixes: acfd92fdfb93 ("pwm: lpc32xx: Set PWM_PIN_LEVEL bit to default value")
Cc: Sylvain Lemieux <slemieux@tycoint.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/pwm/pwm-lpc32xx.c