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Message-Id: <20211005155923.173399-7-marcan@marcan.st>
Date: Wed, 6 Oct 2021 00:59:22 +0900
From: Hector Martin <marcan@...can.st>
To: linux-arm-kernel@...ts.infradead.org
Cc: Hector Martin <marcan@...can.st>, Marc Zyngier <maz@...nel.org>,
Rob Herring <robh+dt@...nel.org>,
Arnd Bergmann <arnd@...nel.org>,
Linus Walleij <linus.walleij@...aro.org>,
Alyssa Rosenzweig <alyssa@...enzweig.io>,
Krzysztof Kozlowski <krzk@...nel.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Mark Kettenis <mark.kettenis@...all.nl>,
Philipp Zabel <p.zabel@...gutronix.de>,
"Rafael J. Wysocki" <rafael@...nel.org>,
devicetree@...r.kernel.org, linux-pm@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-samsung-soc@...r.kernel.org,
linux-serial@...r.kernel.org
Subject: [PATCH 6/7] tty: serial: samsung_tty: Support runtime PM
This allows idle UART devices to be suspended using the standard
runtime-PM framework. The logic is modeled after stm32-usart.
Signed-off-by: Hector Martin <marcan@...can.st>
---
drivers/tty/serial/samsung_tty.c | 88 ++++++++++++++++++++------------
1 file changed, 54 insertions(+), 34 deletions(-)
diff --git a/drivers/tty/serial/samsung_tty.c b/drivers/tty/serial/samsung_tty.c
index e2f49863e9c2..d68e3341adc6 100644
--- a/drivers/tty/serial/samsung_tty.c
+++ b/drivers/tty/serial/samsung_tty.c
@@ -40,6 +40,7 @@
#include <linux/clk.h>
#include <linux/cpufreq.h>
#include <linux/of.h>
+#include <linux/pm_runtime.h>
#include <asm/irq.h>
/* UART name and device definitions */
@@ -1381,31 +1382,49 @@ static void exynos_usi_init(struct uart_port *port)
/* power power management control */
-static void s3c24xx_serial_pm(struct uart_port *port, unsigned int level,
- unsigned int old)
+static int __maybe_unused s3c24xx_serial_runtime_suspend(struct device *dev)
{
+ struct uart_port *port = dev_get_drvdata(dev);
struct s3c24xx_uart_port *ourport = to_ourport(port);
int timeout = 10000;
- ourport->pm_level = level;
+ while (--timeout && !s3c24xx_serial_txempty_nofifo(port))
+ udelay(100);
- switch (level) {
- case 3:
- while (--timeout && !s3c24xx_serial_txempty_nofifo(port))
- udelay(100);
+ if (!IS_ERR(ourport->baudclk))
+ clk_disable_unprepare(ourport->baudclk);
- if (!IS_ERR(ourport->baudclk))
- clk_disable_unprepare(ourport->baudclk);
+ clk_disable_unprepare(ourport->clk);
+ return 0;
+};
- clk_disable_unprepare(ourport->clk);
- break;
+static int __maybe_unused s3c24xx_serial_runtime_resume(struct device *dev)
+{
+ struct uart_port *port = dev_get_drvdata(dev);
+ struct s3c24xx_uart_port *ourport = to_ourport(port);
- case 0:
- clk_prepare_enable(ourport->clk);
+ clk_prepare_enable(ourport->clk);
- if (!IS_ERR(ourport->baudclk))
- clk_prepare_enable(ourport->baudclk);
+ if (!IS_ERR(ourport->baudclk))
+ clk_prepare_enable(ourport->baudclk);
+ return 0;
+};
+
+static void s3c24xx_serial_pm(struct uart_port *port, unsigned int level,
+ unsigned int old)
+{
+ struct s3c24xx_uart_port *ourport = to_ourport(port);
+
+ ourport->pm_level = level;
+ switch (level) {
+ case UART_PM_STATE_OFF:
+ pm_runtime_mark_last_busy(port->dev);
+ pm_runtime_put_sync(port->dev);
+ break;
+
+ case UART_PM_STATE_ON:
+ pm_runtime_get_sync(port->dev);
exynos_usi_init(port);
break;
default:
@@ -2282,18 +2301,15 @@ static int s3c24xx_serial_probe(struct platform_device *pdev)
}
}
+ pm_runtime_get_noresume(&pdev->dev);
+ pm_runtime_set_active(&pdev->dev);
+ pm_runtime_enable(&pdev->dev);
+
dev_dbg(&pdev->dev, "%s: adding port\n", __func__);
uart_add_one_port(&s3c24xx_uart_drv, &ourport->port);
platform_set_drvdata(pdev, &ourport->port);
- /*
- * Deactivate the clock enabled in s3c24xx_serial_init_port here,
- * so that a potential re-enablement through the pm-callback overlaps
- * and keeps the clock enabled in this case.
- */
- clk_disable_unprepare(ourport->clk);
- if (!IS_ERR(ourport->baudclk))
- clk_disable_unprepare(ourport->baudclk);
+ pm_runtime_put_sync(&pdev->dev);
ret = s3c24xx_serial_cpufreq_register(ourport);
if (ret < 0)
@@ -2309,8 +2325,14 @@ static int s3c24xx_serial_remove(struct platform_device *dev)
struct uart_port *port = s3c24xx_dev_to_port(&dev->dev);
if (port) {
+ pm_runtime_get_sync(&dev->dev);
+
s3c24xx_serial_cpufreq_deregister(to_ourport(port));
uart_remove_one_port(&s3c24xx_uart_drv, port);
+
+ pm_runtime_disable(&dev->dev);
+ pm_runtime_set_suspended(&dev->dev);
+ pm_runtime_put_noidle(&dev->dev);
}
uart_unregister_driver(&s3c24xx_uart_drv);
@@ -2319,8 +2341,8 @@ static int s3c24xx_serial_remove(struct platform_device *dev)
}
/* UART power management code */
-#ifdef CONFIG_PM_SLEEP
-static int s3c24xx_serial_suspend(struct device *dev)
+
+static int __maybe_unused s3c24xx_serial_suspend(struct device *dev)
{
struct uart_port *port = s3c24xx_dev_to_port(dev);
@@ -2330,7 +2352,7 @@ static int s3c24xx_serial_suspend(struct device *dev)
return 0;
}
-static int s3c24xx_serial_resume(struct device *dev)
+static int __maybe_unused s3c24xx_serial_resume(struct device *dev)
{
struct uart_port *port = s3c24xx_dev_to_port(dev);
struct s3c24xx_uart_port *ourport = to_ourport(port);
@@ -2350,7 +2372,7 @@ static int s3c24xx_serial_resume(struct device *dev)
return 0;
}
-static int s3c24xx_serial_resume_noirq(struct device *dev)
+static int __maybe_unused s3c24xx_serial_resume_noirq(struct device *dev)
{
struct uart_port *port = s3c24xx_dev_to_port(dev);
struct s3c24xx_uart_port *ourport = to_ourport(port);
@@ -2420,16 +2442,14 @@ static int s3c24xx_serial_resume_noirq(struct device *dev)
}
static const struct dev_pm_ops s3c24xx_serial_pm_ops = {
+#ifdef CONFIG_PM_SLEEP
.suspend = s3c24xx_serial_suspend,
.resume = s3c24xx_serial_resume,
.resume_noirq = s3c24xx_serial_resume_noirq,
+#endif
+ SET_RUNTIME_PM_OPS(s3c24xx_serial_runtime_suspend,
+ s3c24xx_serial_runtime_resume, NULL)
};
-#define SERIAL_SAMSUNG_PM_OPS (&s3c24xx_serial_pm_ops)
-
-#else /* !CONFIG_PM_SLEEP */
-
-#define SERIAL_SAMSUNG_PM_OPS NULL
-#endif /* CONFIG_PM_SLEEP */
/* Console code */
@@ -2924,7 +2944,7 @@ static struct platform_driver samsung_serial_driver = {
.id_table = s3c24xx_serial_driver_ids,
.driver = {
.name = "samsung-uart",
- .pm = SERIAL_SAMSUNG_PM_OPS,
+ .pm = &s3c24xx_serial_pm_ops,
.of_match_table = of_match_ptr(s3c24xx_uart_dt_match),
},
};
--
2.33.0
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