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authorStephen Warren <swarren@nvidia.com>2012-03-03 00:05:46 +0400
committerLinus Walleij <linus.walleij@linaro.org>2012-03-05 14:21:46 +0400
commit0e3db173e2b9fd3b82246516e72c17763eb5f98d (patch)
treece00c29c56332c925766f7f793d388b9670d802f /drivers/pinctrl/core.h
parent7ecdb16fe63e5b356335ebdc236adfb48cef31e1 (diff)
downloadlinux-0e3db173e2b9fd3b82246516e72c17763eb5f98d.tar.xz
pinctrl: add usecount to pins for muxing
Multiple mapping table entries could reference the same pin, and hence "own" it. This would be unusual now that pinctrl_get() represents a single state for a client device, but in the future when it represents all known states for a device, this is quite likely. Implement reference counting for pin ownership to handle this. Signed-off-by: Stephen Warren <swarren@nvidia.com> Acked-by: Dong Aisheng <dong.aisheng@linaro.org> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Diffstat (limited to 'drivers/pinctrl/core.h')
-rw-r--r--drivers/pinctrl/core.h10
1 files changed, 9 insertions, 1 deletions
diff --git a/drivers/pinctrl/core.h b/drivers/pinctrl/core.h
index 5f258b793400..0bc52ecaf710 100644
--- a/drivers/pinctrl/core.h
+++ b/drivers/pinctrl/core.h
@@ -82,7 +82,14 @@ struct pinctrl_setting {
* @name: a name for the pin, e.g. the name of the pin/pad/finger on a
* datasheet or such
* @dynamic_name: if the name of this pin was dynamically allocated
- * @owner: the device holding this pin or NULL of no device has claimed it
+ * @usecount: If zero, the pin is not claimed, and @owner should be NULL.
+ * If non-zero, this pin is claimed by @owner. This field is an integer
+ * rather than a boolean, since pinctrl_get() might process multiple
+ * mapping table entries that refer to, and hence claim, the same group
+ * or pin, and each of these will increment the @usecount.
+ * @owner: The name of the entity owning the pin. Typically, this is the name
+ * of the device that called pinctrl_get(). Alternatively, it may be the
+ * name of the GPIO passed to pinctrl_request_gpio().
*/
struct pin_desc {
struct pinctrl_dev *pctldev;
@@ -90,6 +97,7 @@ struct pin_desc {
bool dynamic_name;
/* These fields only added when supporting pinmux drivers */
#ifdef CONFIG_PINMUX
+ unsigned usecount;
const char *owner;
#endif
};