From patchwork Tue Sep 21 10:33:44 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tony Lindgren X-Patchwork-Id: 12507563 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4ADFFC433FE for ; Tue, 21 Sep 2021 10:34:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 22C5661038 for ; Tue, 21 Sep 2021 10:34:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232130AbhIUKfg (ORCPT ); Tue, 21 Sep 2021 06:35:36 -0400 Received: from muru.com ([72.249.23.125]:35542 "EHLO muru.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232000AbhIUKfa (ORCPT ); Tue, 21 Sep 2021 06:35:30 -0400 Received: from hillo.muru.com (localhost [127.0.0.1]) by muru.com (Postfix) with ESMTP id 118A38127; Tue, 21 Sep 2021 10:34:27 +0000 (UTC) From: Tony Lindgren To: Greg Kroah-Hartman Cc: Andy Shevchenko , Jiri Slaby , Johan Hovold , Vignesh Raghavendra , linux-serial@vger.kernel.org, linux-omap@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 4/6] serial: 8250: Implement prep_tx for power management Date: Tue, 21 Sep 2021 13:33:44 +0300 Message-Id: <20210921103346.64824-5-tony@atomide.com> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210921103346.64824-1-tony@atomide.com> References: <20210921103346.64824-1-tony@atomide.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-omap@vger.kernel.org We can use the prep_tx() call to wake up an idle serial port. This allows ust to remove the depedency to pm_runtime_irq_safe() for 8250_omap driver in the following patches. Signed-off-by: Tony Lindgren --- drivers/tty/serial/8250/8250_port.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c --- a/drivers/tty/serial/8250/8250_port.c +++ b/drivers/tty/serial/8250/8250_port.c @@ -1650,6 +1650,29 @@ static enum hrtimer_restart serial8250_em485_handle_start_tx(struct hrtimer *t) return HRTIMER_NORESTART; } +static int serial8250_prep_tx(struct uart_port *port) +{ + struct uart_8250_port *up = up_to_u8250p(port); + struct device *dev = up->port.dev; + int err; + + if (!(up->capabilities & UART_CAP_RPM)) + return 0; + + if (!pm_runtime_suspended(dev)) { + pm_runtime_mark_last_busy(dev); + return 0; + } + + err = pm_request_resume(dev); + if (err < 0) { + dev_warn(dev, "prep_tx wakeup failed: %d\n", err); + return err; + } + + return -EINPROGRESS; +} + static void serial8250_start_tx(struct uart_port *port) { struct uart_8250_port *up = up_to_u8250p(port); @@ -3227,6 +3250,7 @@ static const struct uart_ops serial8250_pops = { .set_mctrl = serial8250_set_mctrl, .get_mctrl = serial8250_get_mctrl, .stop_tx = serial8250_stop_tx, + .prep_tx = serial8250_prep_tx, .start_tx = serial8250_start_tx, .throttle = serial8250_throttle, .unthrottle = serial8250_unthrottle,