On 30 November 2017 at 16:35, Lee Jones [off-list ref] wrote:

On Thu, 30 Nov 2017, Baolin Wang wrote:

quoted

Some system control registers need hardware spinlock to synchronize
between the multiple subsystems, so we should add hardware spinlock
support for syscon.

Signed-off-by: Baolin Wang <redacted>
Acked-by: Rob Herring <redacted>
---
Changes since v3:
 - Add error handling for of_hwspin_lock_get_id()

Changes since v2:
 - Add acked tag from Rob.

Changes since v1:
 - Remove timeout configuration.
 - Modify the binding file to add hwlocks.
---
 Documentation/devicetree/bindings/mfd/syscon.txt |    1 +
 drivers/mfd/syscon.c                             |   21 +++++++++++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/Documentation/devicetree/bindings/mfd/syscon.txt b/Documentation/devicetree/bindings/mfd/syscon.txt
index 8b92d45..f464cc8 100644
--- a/Documentation/devicetree/bindings/mfd/syscon.txt
+++ b/Documentation/devicetree/bindings/mfd/syscon.txt

@@ -16,6 +16,7 @@ Required properties:
 Optional property:
 - reg-io-width: the size (in bytes) of the IO accesses that should be
   performed on the device.
+- hwlocks: reference to a phandle of a hardware spinlock provider node.

Example?

Perhaps even include the hwlock node (I'm not sure what that would
look like).

Sure, I will add one example node here.

quoted

 Examples:
 gpr: iomuxc-gpr@20e0000 {

diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c
index b93fe4c..caf6a25 100644
--- a/drivers/mfd/syscon.c
+++ b/drivers/mfd/syscon.c

@@ -13,6 +13,7 @@
  */

 #include <linux/err.h>
+#include <linux/hwspinlock.h>
 #include <linux/io.h>
 #include <linux/module.h>
 #include <linux/list.h>

@@ -87,6 +88,26 @@ static struct syscon *of_syscon_register(struct device_node *np)
      if (ret)
              reg_io_width = 4;

+     ret = of_hwspin_lock_get_id(np, 0);
+     if (ret > 0) {
+             syscon_config.hwlock_id = ret;
+             syscon_config.hwlock_mode = HWLOCK_IRQSTATE;
+     } else {
+             switch (ret) {
+             case -ENOENT:
+                     /* ignore missing hwlock, it's optional */

Is your shift key broken? ;)

Please use proper grammar.  Sentences start with capital letters.

OK. Thanks for your comments.

-- 
Baolin.wang
Best Regards
--
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