[PATCH] i2c: OMAP: fix static suspend vs. runtime suspend
From: Rajendra Nayak <hidden>
Date: 2011-01-31 11:28:02
Also in:
linux-i2c, linux-omap
Hi Kevin,
-----Original Message----- From: Kevin Hilman [mailto:khilman at ti.com] Sent: Friday, January 28, 2011 5:49 AM To: Ben Dooks; Rajendra Nayak; linux-i2c at vger.kernel.org Cc: linux-omap at vger.kernel.org; linux-pm at lists.linux-foundation.org;
linux-arm-kernel at lists.infradead.org
Subject: [PATCH] i2c: OMAP: fix static suspend vs. runtime suspend
When runtime PM is enabled, each OMAP i2c device is suspended after
each i2c xfer. However, there are two cases when the static suspend
methods must be used to ensure the devices are suspended:
1) runtime PM is disabled, either at compile time or dynamically
via /sys/devices/.../power/control.
2) an i2c client driver uses i2c during it's suspend callback, thus
leaving the i2c driver active (NOTE: runtime suspend transitions are
disabled during system suspend, so i2c activity during system
suspend will runtime resume the device, but not runtime (re)suspendit.)
Since the actual work to suspend the device is handled by the subsytem, call the bus methods to take care of it.
The patch looks good to me. Thanks for the fix. Validated suspend on OMAP4sdp with the patch. Can you elaborate a bit more on how/why runtime PM transitions are disabled during system suspend, and how is it taken care of that a runtime resume of a device works however a subsequent runtime (re)suspend does not? Regards, Rajendra
quoted hunk ↗ jump to hunk
NOTE: This takes care of a known suspend problem on OMAP3 where the TWL RTC driver does i2c xfers during its suspend path leaving the i2c driver in an active state (since runtime suspend transistions are disabled.) Signed-off-by: Kevin Hilman <redacted> --- Ben, this is a regression in 2.6.38 so hopefully this can be queued in the 2.6.38-rc cycle. Thanks. drivers/i2c/busses/i2c-omap.c | 28 ++++++++++++++++++++++++++++ 1 files changed, 28 insertions(+), 0 deletions(-)diff --git a/drivers/i2c/busses/i2c-omap.c
b/drivers/i2c/busses/i2c-omap.c
quoted hunk ↗ jump to hunk
index b605ff3..0541df9 100644--- a/drivers/i2c/busses/i2c-omap.c +++ b/drivers/i2c/busses/i2c-omap.c@@ -1137,12 +1137,40 @@ omap_i2c_remove(struct platform_device *pdev) return 0; } +#ifdef CONFIG_SUSPEND +static int omap_i2c_suspend(struct device *dev) +{ + if (!pm_runtime_suspended(dev)) + if (dev->bus && dev->bus->pm &&
dev->bus->pm->runtime_suspend)
+ dev->bus->pm->runtime_suspend(dev);
+
+ return 0;
+}
+
+static int omap_i2c_resume(struct device *dev)
+{
+ if (!pm_runtime_suspended(dev))
+ if (dev->bus && dev->bus->pm &&dev->bus->pm->runtime_resume)
+ dev->bus->pm->runtime_resume(dev);
+
+ return 0;
+}
+
+static struct dev_pm_ops omap_i2c_pm_ops = {
+ .suspend = omap_i2c_suspend,
+ .resume = omap_i2c_resume,
+};
+#else
+#define omap_i2c_pm_ops NULL
+#endif
+
static struct platform_driver omap_i2c_driver = {
.probe = omap_i2c_probe,
.remove = omap_i2c_remove,
.driver = {
.name = "omap_i2c",
.owner = THIS_MODULE,
+ .pm = &omap_i2c_pm_ops,
},
};
--
1.7.3.5