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authorMartin Wilck <Martin.Wilck@ts.fujitsu.com>2015-11-30 12:50:05 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-01-26 08:47:25 -0800
commit25cad69f21f5532d99e2ee73c8ab6512bcab614c (patch)
tree0bfc4b5140547e81b9d126b7e1573d4d619d662c /drivers/base/platform.c
parent92e963f50fc74041b5e9e744c330dca48e04f08d (diff)
base/platform: Fix platform drivers with no probe callback
Since b8b2c7d845d5, platform_drv_probe() is called for all platform devices. If drv->probe is NULL, and dev_pm_domain_attach() fails, platform_drv_probe() will return the error code from dev_pm_domain_attach(). This causes real_probe() to enter the "probe_failed" path and set dev->driver to NULL. Before b8b2c7d845d5, real_probe() would assume success if both dev->bus->probe and drv->probe were missing. As a result, a device and driver could be "bound" together just by matching their names; this doesn't work any more after b8b2c7d845d5. This may cause problems later for certain usage of platform_driver_register() and platform_device_register_simple(). I observed a panic while loading the tpm_tis driver with parameter "force=1" (i.e. registering tpm_tis as a platform driver), because tpm_tis_init's assumption that the device returned by platform_device_register_simple() was bound didn't hold any more (tpmm_chip_alloc() dereferences chip->pdev->driver, causing panic). This patch restores the previous (4.3.0 and earlier) behavior of platform_drv_probe() in the case when the associated platform driver has no "probe" function. Fixes: b8b2c7d845d5 ("base/platform: assert that dev_pm_domain callbacks are called unconditionally") Signed-off-by: Martin Wilck <Martin.Wilck@ts.fujitsu.com> Cc: stable <stable@vger.kernel.org> # 4.4 Cc: Martin Fuzzey <mfuzzey@parkeon.com> Acked-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/base/platform.c')
-rw-r--r--drivers/base/platform.c13
1 files changed, 9 insertions, 4 deletions
diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index 73d6e5d39e33..f437afa17f2b 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -558,10 +558,15 @@ static int platform_drv_probe(struct device *_dev)
return ret;
ret = dev_pm_domain_attach(_dev, true);
- if (ret != -EPROBE_DEFER && drv->probe) {
- ret = drv->probe(dev);
- if (ret)
- dev_pm_domain_detach(_dev, true);
+ if (ret != -EPROBE_DEFER) {
+ if (drv->probe) {
+ ret = drv->probe(dev);
+ if (ret)
+ dev_pm_domain_detach(_dev, true);
+ } else {
+ /* don't fail if just dev_pm_domain_attach failed */
+ ret = 0;
+ }
}
if (drv->prevent_deferred_probe && ret == -EPROBE_DEFER) {