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Subject[PATCH 6/9] PM / Domains: Don't attach devices in genpd with multi PM domains
Date
The power-domain DT property may now contain a list of phandles, which
represents that a device are partitioned across multiple PM domains. This
leads to a new situation in genpd_dev_pm_attach(), as only one PM domain
can be attached per device.

To remain things simple for the most common configuration, when a single PM
domain is used, let's treat the multiple PM domain case as being specific.

In other words, let's change genpd_dev_pm_attach() to check for multiple PM
domains and prevent it from attach any PM domain for this case. Instead,
leave this to be managed separately, from following changes to genpd.

Cc: Rob Herring <robh+dt@kernel.org>
Cc: devicetree@vger.kernel.org
Suggested-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
---
drivers/base/power/domain.c | 18 +++++++++++++-----
1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 050ce07..4597e1c 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -2229,10 +2229,10 @@ static void genpd_dev_pm_sync(struct device *dev)
* attaches the device to retrieved pm_domain ops.
*
* Returns 1 on successfully attached PM domain, 0 when the device don't need a
- * PM domain or a negative error code in case of failures. Note that if a
- * power-domain exists for the device, but it cannot be found or turned on,
- * then return -EPROBE_DEFER to ensure that the device is not probed and to
- * re-try again later.
+ * PM domain or when multiple power-domains exists for it, else a negative error
+ * code. Note that if a power-domain exists for the device, but it cannot be
+ * found or turned on, then return -EPROBE_DEFER to ensure that the device is
+ * not probed and to re-try again later.
*/
int genpd_dev_pm_attach(struct device *dev)
{
@@ -2243,10 +2243,18 @@ int genpd_dev_pm_attach(struct device *dev)
if (!dev->of_node)
return 0;

+ /*
+ * Devices with multiple PM domains must be attached separately, as we
+ * can only attach one PM domain per device.
+ */
+ if (of_count_phandle_with_args(dev->of_node, "power-domains",
+ "#power-domain-cells") != 1)
+ return 0;
+
ret = of_parse_phandle_with_args(dev->of_node, "power-domains",
"#power-domain-cells", 0, &pd_args);
if (ret < 0)
- return 0;
+ return ret;

mutex_lock(&gpd_list_lock);
pd = genpd_get_from_provider(&pd_args);
--
2.7.4
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