From patchwork Fri Feb 25 10:36:49 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Sean Young X-Patchwork-Id: 12760077 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 77471C433F5 for ; Fri, 25 Feb 2022 10:38:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233510AbiBYKia (ORCPT ); Fri, 25 Feb 2022 05:38:30 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40228 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239680AbiBYKho (ORCPT ); Fri, 25 Feb 2022 05:37:44 -0500 Received: from gofer.mess.org (gofer.mess.org [IPv6:2a02:8011:d000:212::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 196D39D0C2 for ; Fri, 25 Feb 2022 02:37:02 -0800 (PST) Received: by gofer.mess.org (Postfix, from userid 1000) id 85AD3100F35; Fri, 25 Feb 2022 10:36:49 +0000 (UTC) From: Sean Young To: linux-media@vger.kernel.org Cc: =?utf-8?b?0JzQuNGF0LDQuNC7?= Subject: [PATCH] media: gpio-ir-tx: fix transmit with long spaces on Orange Pi PC Date: Fri, 25 Feb 2022 10:36:49 +0000 Message-Id: <20220225103649.978878-1-sean@mess.org> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Calling udelay for than 1000us does not always yield the correct results. Reported-by: Михаил Signed-off-by: Sean Young --- drivers/media/rc/gpio-ir-tx.c | 28 +++++++++++++++++++++------- 1 file changed, 21 insertions(+), 7 deletions(-) diff --git a/drivers/media/rc/gpio-ir-tx.c b/drivers/media/rc/gpio-ir-tx.c index c6cd2e6d8e65..47277c9f4780 100644 --- a/drivers/media/rc/gpio-ir-tx.c +++ b/drivers/media/rc/gpio-ir-tx.c @@ -48,11 +48,29 @@ static int gpio_ir_tx_set_carrier(struct rc_dev *dev, u32 carrier) return 0; } +static void delay_until(ktime_t until) +{ + /* + * delta should never exceed 0.5 seconds (IR_MAX_DURATION) and on + * m68k ndelay(s64) does not compile; so use s32 rather than s64. + */ + s32 delta; + + while (true) { + delta = ktime_us_delta(until, ktime_get()); + if (delta <= 0) + return; + + /* Don't udelay more than 1ms */ + delta = min(delta, 1000); + udelay(delta); + } +} + static void gpio_ir_tx_unmodulated(struct gpio_ir *gpio_ir, uint *txbuf, uint count) { ktime_t edge; - s32 delta; int i; local_irq_disable(); @@ -63,9 +81,7 @@ static void gpio_ir_tx_unmodulated(struct gpio_ir *gpio_ir, uint *txbuf, gpiod_set_value(gpio_ir->gpio, !(i % 2)); edge = ktime_add_us(edge, txbuf[i]); - delta = ktime_us_delta(edge, ktime_get()); - if (delta > 0) - udelay(delta); + delay_until(edge); } gpiod_set_value(gpio_ir->gpio, 0); @@ -97,9 +113,7 @@ static void gpio_ir_tx_modulated(struct gpio_ir *gpio_ir, uint *txbuf, if (i % 2) { // space edge = ktime_add_us(edge, txbuf[i]); - delta = ktime_us_delta(edge, ktime_get()); - if (delta > 0) - udelay(delta); + delay_until(edge); } else { // pulse ktime_t last = ktime_add_us(edge, txbuf[i]);