From a2f77ae4778d1eef2d273683ccc09fa971111c8c Mon Sep 17 00:00:00 2001 From: =?utf8?q?Uwe=20Kleine-K=C3=B6nig?= Date: Wed, 30 Jul 2025 10:02:20 +0200 Subject: [PATCH] pwm: tiecap: Document behaviour of hardware disable MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit According to David Lechner[1] disabling a tiecap PWM makes the PWM pin an input. The reported problem is fixed in commit deaeeda2051f ("backlight: pwm_bl: Don't rely on a disabled PWM emiting inactive state"). Document the behaviour in the driver for future reference. [1] https://lore.kernel.org/linux-pwm/39a472c0-ba24-de7b-8783-a16a71b172cd@lechnology.com Signed-off-by: Uwe Kleine-König Reviewed-by: David Lechner Link: https://lore.kernel.org/r/20250730080219.183181-2-u.kleine-koenig@baylibre.com Signed-off-by: Uwe Kleine-König --- drivers/pwm/pwm-tiecap.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/pwm/pwm-tiecap.c b/drivers/pwm/pwm-tiecap.c index d91b2bdc88fce..67cc5e8bdb0ef 100644 --- a/drivers/pwm/pwm-tiecap.c +++ b/drivers/pwm/pwm-tiecap.c @@ -3,6 +3,10 @@ * ECAP PWM driver * * Copyright (C) 2012 Texas Instruments, Inc. - https://www.ti.com/ + * + * Hardware properties: + * - On disable the PWM pin becomes an input, so the behaviour depends on + * external wiring. */ #include -- 2.47.3