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 12:07:09 +0000 (14:07 +0200)
commit81e6b51709da162b94e40a445bb60856406beaa1
tree1506b61df74f3694ef8276d9e2ce5bb0acb8d9ee
parentb94def8a475ffc1a32f447db062bb2f0cf3e7125
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