Re: [PATCH 3/6] driver: serial: omap: add prepare/complete callbackfor "no_console_suspend" case

From: Sourav Poddar
Date: Thu Apr 18 2013 - 14:12:13 EST


Hi Kevin,
On Thursday 18 April 2013 11:26 PM, Kevin Hilman wrote:
Sourav Poddar<sourav.poddar@xxxxxx> writes:

The patch adapt the serial core/driver to take care of the case when "no_console_suspend"
is used in the bootargs. The patch will remove dependency to set od->flags to
"OMAP_DEVICE_NO_IDLE_ON_SUSPEND" in serial.c(non dt case) and omap_device.c(dt case).

Prepare and complete callbacks will ensure that clocks remain active for the console
uart when "no_console_suspend" is used in the bootargs.

Signed-off-by: Sourav Poddar<sourav.poddar@xxxxxx>
This changelog needs a rework. The driver itself was not aware of
od->flags and omap_device stuff in general, so it's not really
relevant. The driver is also not directly managing clocks, int's only
doing runtime PM callbacks.

What you want to say in the changelog is that the driver manages
"no_console_suspend" by preventing runtime PM during the suspend path,
which forces the console UART to stay awake.

Yes, looks to the point. Will update the changelog in the next version.
---
drivers/tty/serial/omap-serial.c | 20 ++++++++++++++++++++
1 files changed, 20 insertions(+), 0 deletions(-)

diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
index 08332f3..9ef80cf 100644
--- a/drivers/tty/serial/omap-serial.c
+++ b/drivers/tty/serial/omap-serial.c
@@ -1278,6 +1278,24 @@ static struct uart_driver serial_omap_reg = {
};

#ifdef CONFIG_PM_SLEEP
+static int serial_omap_prepare(struct device *dev)
+{
+ struct uart_omap_port *up = dev_get_drvdata(dev);
+
+ if (!console_suspend_enabled&& uart_console(&up->port))
+ pm_runtime_disable(dev);
+
+ return 0;
+}
+
+static void serial_omap_complete(struct device *dev)
+{
+ struct uart_omap_port *up = dev_get_drvdata(dev);
+
+ if (!console_suspend_enabled&& uart_console(&up->port))
+ pm_runtime_enable(dev);
+}
+
For compilation with !CONFIG_PM_SLEEP, you'll also need:

#else
#define serial_omap_prepare NULL
#define serial_omap_prepare NULL
#endif /* CONFIG_PM_SLEEP */

Ok. Will change this.
Though, just a query/proposal on this, will it be correct if we try to create a macro[1]
in include/linux/pm.h for prepare/complete as it is done for suspend/resume. ?

[1]:
#ifdef CONFIG_PM_SLEEP
#define SET_SYSTEM_SLEEP_PM_PREP_COMP_OPS(prepare_fn, complete_fn) \
.prepare = prepare_fn, \
.complete = complete_fn, \
#else
#define SET_SYSTEM_SLEEP_PM_PREP_COMP_OPS(prepare_fn, complete_fn)
#endif

~Sourav
static int serial_omap_suspend(struct device *dev)
{
struct uart_omap_port *up = dev_get_drvdata(dev);
@@ -1632,6 +1650,8 @@ static const struct dev_pm_ops serial_omap_dev_pm_ops = {
SET_SYSTEM_SLEEP_PM_OPS(serial_omap_suspend, serial_omap_resume)
SET_RUNTIME_PM_OPS(serial_omap_runtime_suspend,
serial_omap_runtime_resume, NULL)
+ .prepare = serial_omap_prepare,
+ .complete = serial_omap_complete,
};

#if defined(CONFIG_OF)
Kevin

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