pinctrl: allow concurrent gpio and mux function ownership of pins

Per recent updates to Documentation/gpio.txt, gpiolib drivers should
inform pinctrl when a GPIO is requested. pinctrl then marks that pin as
in-use for that GPIO function.

When an SoC muxes pins in a group, it's quite possible for the group to
contain e.g. 6 pins, but only 4 of them actually be needed by the HW
module that's mux'd to them. In this case, the other 2 pins could be
used as GPIOs. However, pinctrl marks all the pins within the group as
in-use by the selected mux function. To allow the expected gpiolib
interaction, separate the concepts of pin ownership into two parts: One
for the mux function and one for GPIO usage. Finally, allow those two
ownerships to exist in parallel.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

1 files changed, 7 insertions, 6 deletions

diff --git a/drivers/pinctrl/core.h b/drivers/pinctrl/core.h
index efbfb62ab14..17ecf651b12 100644
--- a/drivers/pinctrl/core.h
+++ b/drivers/pinctrl/core.h
@@ -119,15 +119,15 @@ 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
- * @usecount: If zero, the pin is not claimed, and @owner should be NULL.
+ * @mux_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().
+ * @mux_owner: The name of device that called pinctrl_get().
  * @mux_setting: The most recent selected mux setting for this pin, if any.
+ * @gpio_owner: If pinctrl_request_gpio() was called for this pin, this is
+ *	the name of the GPIO that "owns" this pin.
  */
 struct pin_desc {
 	struct pinctrl_dev *pctldev;
@@ -135,9 +135,10 @@ struct pin_desc {
 	bool dynamic_name;
 	/* These fields only added when supporting pinmux drivers */
 #ifdef CONFIG_PINMUX
-	unsigned usecount;
-	const char *owner;
+	unsigned mux_usecount;
+	const char *mux_owner;
 	const struct pinctrl_setting_mux *mux_setting;
+	const char *gpio_owner;
 #endif
 };