From:   Tony Lindgren <tony@atomide.com>
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc:     Andy Shevchenko <andriy.shevchenko@intel.com>,
        Jiri Slaby <jirislaby@kernel.org>,
        Johan Hovold <johan@kernel.org>,
        Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
        Vignesh Raghavendra <vigneshr@ti.com>,
        linux-serial@vger.kernel.org, linux-omap@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Subject: [PATCH 5/7] serial: 8250_omap: Require a valid wakeirq for deeper idle states
Date:   Mon, 15 Nov 2021 10:42:01 +0200
Message-Id: <20211115084203.56478-6-tony@atomide.com>
In-Reply-To: <20211115084203.56478-1-tony@atomide.com>
References: <20211115084203.56478-1-tony@atomide.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

For deeper idle states the 8250 device gets powered off. The wakeup is
handled with a separate wakeirq controller monitoring the RX pin.

Let's check for a valid wakeirq before enabling deeper idle states.

Signed-off-by: Tony Lindgren <tony@atomide.com>
---
 drivers/tty/serial/8250/8250_omap.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c
--- a/drivers/tty/serial/8250/8250_omap.c
+++ b/drivers/tty/serial/8250/8250_omap.c
@@ -133,6 +133,7 @@ struct omap8250_priv {
 	spinlock_t rx_dma_lock;
 	bool rx_dma_broken;
 	bool throttled;
+	unsigned int allow_rpm:1;
 };
 
 struct omap8250_dma_params {
@@ -676,6 +677,7 @@ static int omap_8250_startup(struct uart_port *port)
 		ret = dev_pm_set_dedicated_wake_irq(port->dev, priv->wakeirq);
 		if (ret)
 			return ret;
+		priv->allow_rpm = 1;
 	}
 
 	pm_runtime_get_sync(port->dev);
@@ -722,6 +724,10 @@ static int omap_8250_startup(struct uart_port *port)
 	if (up->dma && !(priv->habit & UART_HAS_EFR2))
 		up->dma->rx_dma(up);
 
+	/* Block runtime PM if no wakeirq, paired with shutdown */
+	if (!priv->allow_rpm)
+		pm_runtime_get_noresume(port->dev);
+
 	pm_runtime_mark_last_busy(port->dev);
 	pm_runtime_put_autosuspend(port->dev);
 	return 0;
@@ -760,6 +766,10 @@ static void omap_8250_shutdown(struct uart_port *port)
 		serial_out(up, UART_LCR, up->lcr & ~UART_LCR_SBC);
 	serial_out(up, UART_FCR, UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
 
+	/* Clear possible PM runtime block to pair with startup */
+	if (!priv->allow_rpm)
+		pm_runtime_put_noidle(port->dev);
+
 	pm_runtime_mark_last_busy(port->dev);
 	pm_runtime_put_autosuspend(port->dev);
 	free_irq(port->irq, port);
-- 
2.33.1