linux-kernel - [PATCH 4/5] serial: 8250: omap: Support wakeup pinctrl state

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Date: Thu, 23 May 2024 09:58:18 +0200
From: Markus Schneider-Pargmann <msp@...libre.com>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Jiri Slaby <jirislaby@...nel.org>,
	Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Tony Lindgren <tony@...mide.com>,
	John Ogness <john.ogness@...utronix.de>,
	Markus Schneider-Pargmann <msp@...libre.com>,
	Uwe Kleine-König <u.kleine-koenig@...gutronix.de>,
	Ronald Wahl <ronald.wahl@...itan.com>,
	Thomas Richard <thomas.richard@...tlin.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
	Arnd Bergmann <arnd@...db.de>,
	Vignesh Raghavendra <vigneshr@...com>
Cc: Vibhore Vardhan <vibhore@...com>,
	Kevin Hilman <khilman@...libre.com>,
	Dhruva Gole <d-gole@...com>,
	linux-kernel@...r.kernel.org,
	linux-serial@...r.kernel.org,
	devicetree@...r.kernel.org
Subject: [PATCH 4/5] serial: 8250: omap: Support wakeup pinctrl state

UART can be used as a wakeup source for am62 from a powered-off SoC
state. To enable wakeup from UART am62 requires a wakeup flag being set
in the pinctrl.

If the device is marked as wakeup enabled, select the 'wakeup' pinctrl
state on sys_off.

Signed-off-by: Markus Schneider-Pargmann <msp@...libre.com>
---
 drivers/tty/serial/8250/8250_omap.c | 39 +++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c
index 5b7508dfb5d8..617a421a1396 100644
--- a/drivers/tty/serial/8250/8250_omap.c
+++ b/drivers/tty/serial/8250/8250_omap.c
@@ -27,8 +27,10 @@
 #include <linux/pm_qos.h>
 #include <linux/pm_wakeirq.h>
 #include <linux/dma-mapping.h>
+#include <linux/reboot.h>
 #include <linux/sys_soc.h>
 #include <linux/pm_domain.h>
+#include <linux/pinctrl/consumer.h>
 
 #include "8250.h"
 
@@ -149,6 +151,9 @@ struct omap8250_priv {
 	spinlock_t rx_dma_lock;
 	bool rx_dma_broken;
 	bool throttled;
+
+	struct pinctrl *pinctrl;
+	struct pinctrl_state *pinctrl_wakeup;
 };
 
 struct omap8250_dma_params {
@@ -1345,6 +1350,30 @@ static int omap8250_no_handle_irq(struct uart_port *port)
 	return 0;
 }
 
+static int omap8250_select_wakeup_pinctrl(struct device *dev,
+					  struct omap8250_priv *priv)
+{
+	if (IS_ERR_OR_NULL(priv->pinctrl_wakeup))
+		return 0;
+
+	if (!device_may_wakeup(dev))
+		return 0;
+
+	return pinctrl_select_state(priv->pinctrl, priv->pinctrl_wakeup);
+}
+
+static int omap8250_sysoff_handler(struct sys_off_data *data)
+{
+	struct omap8250_priv *priv = dev_get_drvdata(data->dev);
+	int ret;
+
+	ret = omap8250_select_wakeup_pinctrl(data->dev, priv);
+	if (ret)
+		dev_err(data->dev, "Failed to select pinctrl state 'wakeup', continuing poweroff\n");
+
+	return NOTIFY_DONE;
+}
+
 static struct omap8250_dma_params am654_dma = {
 	.rx_size = SZ_2K,
 	.rx_trigger = 1,
@@ -1566,6 +1595,16 @@ static int omap8250_probe(struct platform_device *pdev)
 	priv->line = ret;
 	pm_runtime_mark_last_busy(&pdev->dev);
 	pm_runtime_put_autosuspend(&pdev->dev);
+
+	priv->pinctrl = devm_pinctrl_get(&pdev->dev);
+	if (!IS_ERR_OR_NULL(priv->pinctrl))
+		priv->pinctrl_wakeup = pinctrl_lookup_state(priv->pinctrl, "wakeup");
+
+	devm_register_sys_off_handler(&pdev->dev,
+				      SYS_OFF_MODE_POWER_OFF_PREPARE,
+				      SYS_OFF_PRIO_DEFAULT,
+				      omap8250_sysoff_handler, NULL);
+
 	return 0;
 err:
 	pm_runtime_dont_use_autosuspend(&pdev->dev);
-- 
2.43.0