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 12:08:58 +0000 (14:08 +0200)
commit322b70b522abe03cd59712bb47a72eddd835d19d
tree13a4a9422f9066ccb58379519880754bbc3835f5
parentc63df77c40ca40979ed8bb02b4a07500eef6cd28
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