* [PATCH v2] pinctrl: implement pinctrl deferred probing
@ 2012-04-11 8:34 ` Linus Walleij
0 siblings, 0 replies; 8+ messages in thread
From: Linus Walleij @ 2012-04-11 8:34 UTC (permalink / raw)
To: linux-kernel, linux-arm-kernel
Cc: Stephen Warren, Shawn Guo, Thomas Abraham, Dong Aisheng,
Rajendra Nayak, Haojian Zhuang, Linus Walleij, Mark Brown,
Arnd Bergmann
From: Linus Walleij <linus.walleij@linaro.org>
If drivers try to obtain pinctrl handles for a pin controller that
has not yet registered to the subsystem, we need to be able to
back out and retry with deferred probing. So let's return
-EPROBE_DEFER whenever this location fails. Also downgrade the
errors to info, maybe we will even set them to debug once the
deferred probing is commonplace.
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
Documentation/pinctrl.txt | 5 +++++
drivers/pinctrl/core.c | 9 ++++++---
drivers/pinctrl/devicetree.c | 6 +++---
3 files changed, 14 insertions(+), 6 deletions(-)
diff --git a/Documentation/pinctrl.txt b/Documentation/pinctrl.txt
index eb46b1c..4431c3e7 100644
--- a/Documentation/pinctrl.txt
+++ b/Documentation/pinctrl.txt
@@ -1043,6 +1043,11 @@ quickly poking some registers.
The pins are allocated for your device when you issue the pinctrl_get() call,
after this you should be able to see this in the debugfs listing of all pins.
+NOTE: the pinctrl system will return -EPROBE_DEFER if it cannot find the
+requested pinctrl handles, for example if the pinctrl driver has not yet
+registered. Thus make sure that the error path in your driver gracefully
+cleans up and is ready to retry the probing later in the startup process.
+
System pin control hogging
==========================
diff --git a/drivers/pinctrl/core.c b/drivers/pinctrl/core.c
index 7ff8690..59027ab 100644
--- a/drivers/pinctrl/core.c
+++ b/drivers/pinctrl/core.c
@@ -518,11 +518,14 @@ static int add_setting(struct pinctrl *p, struct pinctrl_map const *map)
setting->pctldev = get_pinctrl_dev_from_devname(map->ctrl_dev_name);
if (setting->pctldev == NULL) {
- dev_err(p->dev, "unknown pinctrl device %s in map entry",
+ dev_info(p->dev, "unknown pinctrl device %s in map entry, deferring probe",
map->ctrl_dev_name);
kfree(setting);
- /* Eventually, this should trigger deferred probe */
- return -ENODEV;
+ /*
+ * OK let us guess that the driver is not there yet, and
+ * let's defer obtaining this pinctrl handle to later...
+ */
+ return -EPROBE_DEFER;
}
switch (map->type) {
diff --git a/drivers/pinctrl/devicetree.c b/drivers/pinctrl/devicetree.c
index 5ef2feb..fcb1de4 100644
--- a/drivers/pinctrl/devicetree.c
+++ b/drivers/pinctrl/devicetree.c
@@ -121,11 +121,11 @@ static int dt_to_map_one_config(struct pinctrl *p, const char *statename,
for (;;) {
np_pctldev = of_get_next_parent(np_pctldev);
if (!np_pctldev || of_node_is_root(np_pctldev)) {
- dev_err(p->dev, "could not find pctldev for node %s\n",
+ dev_info(p->dev, "could not find pctldev for node %s, deferring probe\n",
np_config->full_name);
of_node_put(np_pctldev);
- /* FIXME: This should trigger deferrered probe */
- return -ENODEV;
+ /* OK let's just assume this will appear later then */
+ return -EPROBE_DEFER;
}
pctldev = find_pinctrl_by_of_node(np_pctldev);
if (pctldev)
--
1.7.9.2
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH v2] pinctrl: implement pinctrl deferred probing
@ 2012-04-11 8:34 ` Linus Walleij
0 siblings, 0 replies; 8+ messages in thread
From: Linus Walleij @ 2012-04-11 8:34 UTC (permalink / raw)
To: linux-arm-kernel
From: Linus Walleij <linus.walleij@linaro.org>
If drivers try to obtain pinctrl handles for a pin controller that
has not yet registered to the subsystem, we need to be able to
back out and retry with deferred probing. So let's return
-EPROBE_DEFER whenever this location fails. Also downgrade the
errors to info, maybe we will even set them to debug once the
deferred probing is commonplace.
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
Documentation/pinctrl.txt | 5 +++++
drivers/pinctrl/core.c | 9 ++++++---
drivers/pinctrl/devicetree.c | 6 +++---
3 files changed, 14 insertions(+), 6 deletions(-)
diff --git a/Documentation/pinctrl.txt b/Documentation/pinctrl.txt
index eb46b1c..4431c3e7 100644
--- a/Documentation/pinctrl.txt
+++ b/Documentation/pinctrl.txt
@@ -1043,6 +1043,11 @@ quickly poking some registers.
The pins are allocated for your device when you issue the pinctrl_get() call,
after this you should be able to see this in the debugfs listing of all pins.
+NOTE: the pinctrl system will return -EPROBE_DEFER if it cannot find the
+requested pinctrl handles, for example if the pinctrl driver has not yet
+registered. Thus make sure that the error path in your driver gracefully
+cleans up and is ready to retry the probing later in the startup process.
+
System pin control hogging
==========================
diff --git a/drivers/pinctrl/core.c b/drivers/pinctrl/core.c
index 7ff8690..59027ab 100644
--- a/drivers/pinctrl/core.c
+++ b/drivers/pinctrl/core.c
@@ -518,11 +518,14 @@ static int add_setting(struct pinctrl *p, struct pinctrl_map const *map)
setting->pctldev = get_pinctrl_dev_from_devname(map->ctrl_dev_name);
if (setting->pctldev == NULL) {
- dev_err(p->dev, "unknown pinctrl device %s in map entry",
+ dev_info(p->dev, "unknown pinctrl device %s in map entry, deferring probe",
map->ctrl_dev_name);
kfree(setting);
- /* Eventually, this should trigger deferred probe */
- return -ENODEV;
+ /*
+ * OK let us guess that the driver is not there yet, and
+ * let's defer obtaining this pinctrl handle to later...
+ */
+ return -EPROBE_DEFER;
}
switch (map->type) {
diff --git a/drivers/pinctrl/devicetree.c b/drivers/pinctrl/devicetree.c
index 5ef2feb..fcb1de4 100644
--- a/drivers/pinctrl/devicetree.c
+++ b/drivers/pinctrl/devicetree.c
@@ -121,11 +121,11 @@ static int dt_to_map_one_config(struct pinctrl *p, const char *statename,
for (;;) {
np_pctldev = of_get_next_parent(np_pctldev);
if (!np_pctldev || of_node_is_root(np_pctldev)) {
- dev_err(p->dev, "could not find pctldev for node %s\n",
+ dev_info(p->dev, "could not find pctldev for node %s, deferring probe\n",
np_config->full_name);
of_node_put(np_pctldev);
- /* FIXME: This should trigger deferrered probe */
- return -ENODEV;
+ /* OK let's just assume this will appear later then */
+ return -EPROBE_DEFER;
}
pctldev = find_pinctrl_by_of_node(np_pctldev);
if (pctldev)
--
1.7.9.2
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH v2] pinctrl: implement pinctrl deferred probing
2012-04-11 8:34 ` Linus Walleij
@ 2012-04-11 15:43 ` Stephen Warren
-1 siblings, 0 replies; 8+ messages in thread
From: Stephen Warren @ 2012-04-11 15:43 UTC (permalink / raw)
To: Linus Walleij
Cc: linux-kernel, linux-arm-kernel, Shawn Guo, Thomas Abraham,
Dong Aisheng, Rajendra Nayak, Haojian Zhuang, Linus Walleij,
Mark Brown, Arnd Bergmann
On 04/11/2012 02:34 AM, Linus Walleij wrote:
> From: Linus Walleij <linus.walleij@linaro.org>
>
> If drivers try to obtain pinctrl handles for a pin controller that
> has not yet registered to the subsystem, we need to be able to
> back out and retry with deferred probing. So let's return
> -EPROBE_DEFER whenever this location fails. Also downgrade the
> errors to info, maybe we will even set them to debug once the
> deferred probing is commonplace.
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH v2] pinctrl: implement pinctrl deferred probing
@ 2012-04-11 15:43 ` Stephen Warren
0 siblings, 0 replies; 8+ messages in thread
From: Stephen Warren @ 2012-04-11 15:43 UTC (permalink / raw)
To: linux-arm-kernel
On 04/11/2012 02:34 AM, Linus Walleij wrote:
> From: Linus Walleij <linus.walleij@linaro.org>
>
> If drivers try to obtain pinctrl handles for a pin controller that
> has not yet registered to the subsystem, we need to be able to
> back out and retry with deferred probing. So let's return
> -EPROBE_DEFER whenever this location fails. Also downgrade the
> errors to info, maybe we will even set them to debug once the
> deferred probing is commonplace.
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2] pinctrl: implement pinctrl deferred probing
2012-04-11 8:34 ` Linus Walleij
@ 2012-04-12 17:09 ` Mark Brown
-1 siblings, 0 replies; 8+ messages in thread
From: Mark Brown @ 2012-04-12 17:09 UTC (permalink / raw)
To: Linus Walleij
Cc: linux-kernel, linux-arm-kernel, Stephen Warren, Shawn Guo,
Thomas Abraham, Dong Aisheng, Rajendra Nayak, Haojian Zhuang,
Linus Walleij, Arnd Bergmann
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On Wed, Apr 11, 2012 at 10:34:08AM +0200, Linus Walleij wrote:
> From: Linus Walleij <linus.walleij@linaro.org>
>
> If drivers try to obtain pinctrl handles for a pin controller that
> has not yet registered to the subsystem, we need to be able to
> back out and retry with deferred probing. So let's return
> -EPROBE_DEFER whenever this location fails. Also downgrade the
> errors to info, maybe we will even set them to debug once the
> deferred probing is commonplace.
Reviwed-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Note that the probe deferral code already has info level logs every time
it does anything so you'll probably have a hint from that when it kicks
into action.
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^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH v2] pinctrl: implement pinctrl deferred probing
@ 2012-04-12 17:09 ` Mark Brown
0 siblings, 0 replies; 8+ messages in thread
From: Mark Brown @ 2012-04-12 17:09 UTC (permalink / raw)
To: linux-arm-kernel
On Wed, Apr 11, 2012 at 10:34:08AM +0200, Linus Walleij wrote:
> From: Linus Walleij <linus.walleij@linaro.org>
>
> If drivers try to obtain pinctrl handles for a pin controller that
> has not yet registered to the subsystem, we need to be able to
> back out and retry with deferred probing. So let's return
> -EPROBE_DEFER whenever this location fails. Also downgrade the
> errors to info, maybe we will even set them to debug once the
> deferred probing is commonplace.
Reviwed-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Note that the probe deferral code already has info level logs every time
it does anything so you'll probably have a hint from that when it kicks
into action.
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^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2] pinctrl: implement pinctrl deferred probing
2012-04-12 17:09 ` Mark Brown
@ 2012-04-12 17:34 ` Linus Walleij
-1 siblings, 0 replies; 8+ messages in thread
From: Linus Walleij @ 2012-04-12 17:34 UTC (permalink / raw)
To: Mark Brown
Cc: Linus Walleij, linux-kernel, linux-arm-kernel, Stephen Warren,
Shawn Guo, Thomas Abraham, Dong Aisheng, Rajendra Nayak,
Haojian Zhuang, Arnd Bergmann
On Thu, Apr 12, 2012 at 7:09 PM, Mark Brown
<broonie@opensource.wolfsonmicro.com> wrote:
> Reviwed-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Thanks!
> Note that the probe deferral code already has info level logs every time
> it does anything so you'll probably have a hint from that when it kicks
> into action.
Yeah, but these messages tell you what caused the deferral.
I'll take some patches the day someone thinks the kernel is
getting too talkative...
Yours,
Linus Walleij
^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH v2] pinctrl: implement pinctrl deferred probing
@ 2012-04-12 17:34 ` Linus Walleij
0 siblings, 0 replies; 8+ messages in thread
From: Linus Walleij @ 2012-04-12 17:34 UTC (permalink / raw)
To: linux-arm-kernel
On Thu, Apr 12, 2012 at 7:09 PM, Mark Brown
<broonie@opensource.wolfsonmicro.com> wrote:
> Reviwed-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Thanks!
> Note that the probe deferral code already has info level logs every time
> it does anything so you'll probably have a hint from that when it kicks
> into action.
Yeah, but these messages tell you what caused the deferral.
I'll take some patches the day someone thinks the kernel is
getting too talkative...
Yours,
Linus Walleij
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2012-04-12 17:35 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2012-04-11 8:34 [PATCH v2] pinctrl: implement pinctrl deferred probing Linus Walleij
2012-04-11 8:34 ` Linus Walleij
2012-04-11 15:43 ` Stephen Warren
2012-04-11 15:43 ` Stephen Warren
2012-04-12 17:09 ` Mark Brown
2012-04-12 17:09 ` Mark Brown
2012-04-12 17:34 ` Linus Walleij
2012-04-12 17:34 ` Linus Walleij
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