[PATCH 2/3] ARM: OMAP2+: omap_device: add pinctrl handling
From: Grygorii Strashko
Date: Wed Jul 17 2013 - 07:44:34 EST
Before switching to DT pinctrl states of OMAP IPs have been handled by hwmod
framework. After switching to DT-boot the pinctrl handling was dropped from
hwmod framework and, as it was recommended, OMAP IP's drivers have to be updated
to handle pinctrl states by itself using pinctrl_pm_select_xx() helpers
(see http://lists.infradead.org/pipermail/linux-arm-kernel/2013-June/173514.html)
But this is not right for OMAP2+ SoC where real IPs state is controlled
by omap_device core which enables/disables modules & clocks actually.
For example, if OMAP I2C driver will handle pinctrl state during system wide
suspend the following issue may occure:
- suspend_noirq - I2C device can be still active because of PM auto-suspend
|-_od_suspend_noirq
|- omap_i2c_suspend_noirq
|- PINs state set to SLEEP
|- pm_generic_runtime_suspend
|- omap_i2c_runtime_suspend()
|- PINs state set to IDLE <--- *oops* PINs state is IDLE and not SLEEP
|- omap_device_idle()
|- omap_hwmod_idle()
|- _idle()
|- disbale module (sysc&clocks)
- resume_noirq - I2C was active before suspend
|-_od_resume_noirq
|- omap_hwmod_enable()
|- _enable()
|- enable module (sysc&clocks)
|- pm_generic_runtime_resume
|- omap_i2c_runtime_resume()
|- PINs state set to DEFAULT <--- !!!!
|- omap_i2c_resume_noirq
|- PINs state set to DEFAULT
|- PINs state set to IDLE <--- *big oops* we have active module and its
PINs state is IDLE
(see https://patchwork.kernel.org/patch/2642101/)
Of course, everything can be handled by adding a tons of code in ecah driver to
check PM state of device and override default behavior of omap_device core, but
this not good.
Hence, add pinctrl handling in omap_device core as shown below:
+
|
| .probe()
|
+-----v--------+
| |
| default |
| |
+----+--+------+
| |
pm_runtime_get()| | pm_runtime_put()
+----------------+ +------------+
| |
+------v------+ pm_runtime_put()+-------v-----+
| +-----------------> |
+-----------> Active |pm_runtime_get() | Idle <----------+
| | <-----------------+ | |
| +-------+-----+ +-------+-----+ |
| |.suspend_noirq() |.suspend_noirq()|
| | | |
| | | |
| | | |
| | | |
| +-------v-----+ +-------v-----+ |
| | | | | |
+-----------+ Sleep ------+ | Sleep +----------+
.resume_noirq() | | | | |.resume_noirq()
+-------|-----+ | +-------------+
| Idle |
+-----------+
1) on PM runtime resume
- switch pinctrl state to "active"
2) on PM runtime suspend
- switch pinctrl state to "idle"
3) during system wide suspend
- switch pinctrl state to "sleep" or "idle" if omap_device core disables device
- switch pinctrl state to "sleep" if device has been disabled already
4) during system wide resume
- switch pinctrl state to "active" if omap_device core has
disabled device during suspend
- switch pinctrl state to "idle" if device was already disabled before suspend
This will enable pinctrl for all OMAP2+ IP's drivers by default -
no changes in code is needed and only DT data will need to be updated
(add "default", "active", "idle", "sleep" states).
Related discussions:
- [3/3] i2c: nomadik: use pinctrl PM helpers
https://patchwork.kernel.org/patch/2670291/
- mmc: omap_hsmmc: Remux pins to support SDIO interrupt and PM runtime
https://patchwork.kernel.org/patch/2690191/
- [PATCH 00/11] drivers: Add Pinctrl PM support
https://lkml.org/lkml/2013/5/31/210
CC: Linus Walleij <linus.walleij@xxxxxxxxxx>
Cc: Stephen Warren <swarren@xxxxxxxxxxxxx>
Signed-off-by: Grygorii Strashko <grygorii.strashko@xxxxxx>
---
arch/arm/mach-omap2/omap_device.c | 40 +++++++++++++++++++++++++++++++------
1 file changed, 34 insertions(+), 6 deletions(-)
diff --git a/arch/arm/mach-omap2/omap_device.c b/arch/arm/mach-omap2/omap_device.c
index 5cc9287..4ebdbd7 100644
--- a/arch/arm/mach-omap2/omap_device.c
+++ b/arch/arm/mach-omap2/omap_device.c
@@ -39,6 +39,7 @@
#include "soc.h"
#include "omap_device.h"
#include "omap_hwmod.h"
+#include "iomap.h"
/* Private functions */
@@ -582,8 +583,10 @@ static int _od_runtime_suspend(struct device *dev)
ret = pm_generic_runtime_suspend(dev);
- if (!ret)
+ if (!ret) {
omap_device_idle(pdev);
+ pinctrl_pm_select_idle_state(dev);
+ }
return ret;
}
@@ -592,12 +595,25 @@ static int _od_runtime_resume(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
+ pinctrl_pm_select_active_state(dev);
+
omap_device_enable(pdev);
return pm_generic_runtime_resume(dev);
}
#endif
+void _od_suspend_sel_pinctrl_state(struct device *dev)
+{
+ if (!dev->pins)
+ return;
+ /* try to select *deepest* pinctrl state */
+ if (IS_ERR(dev->pins->sleep_state))
+ pinctrl_pm_select_idle_state(dev);
+ else
+ pinctrl_pm_select_sleep_state(dev);
+}
+
#ifdef CONFIG_SUSPEND
static int _od_suspend_noirq(struct device *dev)
{
@@ -610,11 +626,19 @@ static int _od_suspend_noirq(struct device *dev)
return 0;
ret = pm_generic_suspend_noirq(dev);
-
- if (!ret && !pm_runtime_status_suspended(dev)) {
- if (pm_generic_runtime_suspend(dev) == 0) {
- omap_device_idle(pdev);
- od->flags |= OMAP_DEVICE_SUSPENDED;
+ if (!ret) {
+ if (!pm_runtime_status_suspended(dev)) {
+ if (pm_generic_runtime_suspend(dev) == 0) {
+ omap_device_idle(pdev);
+ od->flags |= OMAP_DEVICE_SUSPENDED;
+ _od_suspend_sel_pinctrl_state(dev);
+ }
+ } else {
+ /*
+ * "idle" pinctrl state already applied -
+ * try to set "sleep" state
+ */
+ pinctrl_pm_select_sleep_state(dev);
}
}
@@ -630,7 +654,11 @@ static int _od_resume_noirq(struct device *dev)
!pm_runtime_status_suspended(dev)) {
od->flags &= ~OMAP_DEVICE_SUSPENDED;
omap_device_enable(pdev);
+ pinctrl_pm_select_active_state(dev);
pm_generic_runtime_resume(dev);
+ } else if (pm_runtime_status_suspended(dev)) {
+ /* switch back to "idle" pinctrl state */
+ pinctrl_pm_select_idle_state(dev);
}
return pm_generic_resume_noirq(dev);
--
1.7.9.5
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