Re: [PATCH v2] serial: 8250_of: Add basic PM runtime support

From: David Lechner
Date: Wed Aug 09 2017 - 19:09:08 EST


On 08/07/2017 03:46 PM, Franklin S Cooper Jr wrote:
Add basic PM Runtime support.

Signed-off-by: Franklin S Cooper Jr <fcooper@xxxxxx>
---

Version 2 changes:
Fix build error.
Build tested using allmodconfig

drivers/tty/serial/8250/8250_of.c | 35 ++++++++++++++++++++++++-----------
1 file changed, 24 insertions(+), 11 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_of.c b/drivers/tty/serial/8250/8250_of.c
index 6c5a8ca..9bad8bae 100644
--- a/drivers/tty/serial/8250/8250_of.c
+++ b/drivers/tty/serial/8250/8250_of.c
@@ -18,6 +18,7 @@
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/of_platform.h>
+#include <linux/pm_runtime.h>
#include <linux/clk.h>
#include <linux/reset.h>
@@ -65,6 +66,10 @@ static int of_platform_serial_setup(struct platform_device *ofdev,
int ret;
memset(port, 0, sizeof *port);
+
+ pm_runtime_enable(&ofdev->dev);
+ pm_runtime_get_sync(&ofdev->dev);
+
if (of_property_read_u32(np, "clock-frequency", &clk)) {
/* Get clk rate through clk driver if present */
@@ -72,12 +77,13 @@ static int of_platform_serial_setup(struct platform_device *ofdev,
if (IS_ERR(info->clk)) {
dev_warn(&ofdev->dev,
"clk or clock-frequency not defined\n");
- return PTR_ERR(info->clk);
+ ret = PTR_ERR(info->clk);
+ goto err_pmruntime;
}
ret = clk_prepare_enable(info->clk);
if (ret < 0)
- return ret;
+ goto err_pmruntime;
clk = clk_get_rate(info->clk);
}
@@ -170,8 +176,10 @@ static int of_platform_serial_setup(struct platform_device *ofdev,
err_dispose:
irq_dispose_mapping(port->irq);
err_unprepare:
- if (info->clk)
- clk_disable_unprepare(info->clk);
+ clk_disable_unprepare(info->clk);
+err_pmruntime:
+ pm_runtime_put_sync(&ofdev->dev);
+ pm_runtime_disable(&ofdev->dev);
return ret;
}
@@ -227,8 +235,9 @@ static int of_platform_serial_probe(struct platform_device *ofdev)
return 0;
err_dispose:
irq_dispose_mapping(port8250.port.irq);
- if (info->clk)
- clk_disable_unprepare(info->clk);
+ pm_runtime_put_sync(&ofdev->dev);
+ pm_runtime_disable(&ofdev->dev);
+ clk_disable_unprepare(info->clk);
err_free:
kfree(info);
return ret;
@@ -244,8 +253,9 @@ static int of_platform_serial_remove(struct platform_device *ofdev)
serial8250_unregister_port(info->line);
reset_control_assert(info->rst);
- if (info->clk)
- clk_disable_unprepare(info->clk);
+ pm_runtime_put_sync(&ofdev->dev);
+ pm_runtime_disable(&ofdev->dev);
+ clk_disable_unprepare(info->clk);
kfree(info);
return 0;
}
@@ -259,9 +269,10 @@ static int of_serial_suspend(struct device *dev)
serial8250_suspend_port(info->line);
- if (info->clk && (!uart_console(port) || console_suspend_enabled))
+ if ((!uart_console(port) || console_suspend_enabled)) {

Extra pair of parenthesis can be removed. ^

+ pm_runtime_put_sync(dev);
clk_disable_unprepare(info->clk);
-
+ }
return 0;
}
@@ -271,8 +282,10 @@ static int of_serial_resume(struct device *dev)
struct uart_8250_port *port8250 = serial8250_get_port(info->line);
struct uart_port *port = &port8250->port;
- if (info->clk && (!uart_console(port) || console_suspend_enabled))
+ if ((!uart_console(port) || console_suspend_enabled)) {

Extra pair of parenthesis can be removed. ^

+ pm_runtime_get_sync(dev);
clk_prepare_enable(info->clk);
+ }
serial8250_resume_port(info->line);