gpio: core: Decouple open drain/source flag with active low/high

Currently, the GPIO interface is said to Open Drain if it is Single
Ended and active LOW. Similarly, it is said as Open Source if it is
Single Ended and active HIGH.

The active HIGH/LOW is used in the interface for setting the pin
state to HIGH or LOW when enabling/disabling the interface.

In Open Drain interface, pin is set to HIGH by putting pin in
high impedance and LOW by driving to the LOW.

In Open Source interface, pin is set to HIGH by driving pin to
HIGH and set to LOW by putting pin in high impedance.

With above, the Open Drain/Source is unrelated to the active LOW/HIGH
in interface. There is interface where the enable/disable of interface
is ether active LOW or HIGH but it is Open Drain type.

Hence decouple the Open Drain with Single Ended + Active LOW and
Open Source with Single Ended + Active HIGH.

Adding different flag for the Open Drain/Open Source which is valid
only when Single ended flag is enabled.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c
index 975b9f6cf4082dfcfde1d98e8a868dd935b867bd..b13b7c7c335f415b6d952fb084250f5c18bfa5e0 100644 (file)
--- a/drivers/gpio/gpiolib-of.c
+++ b/drivers/gpio/gpiolib-of.c
@@ -147,7 +147,7 @@ struct gpio_desc *of_find_gpio(struct device *dev, const char *con_id,
                *flags |= GPIO_ACTIVE_LOW;
 
        if (of_flags & OF_GPIO_SINGLE_ENDED) {
-               if (of_flags & OF_GPIO_ACTIVE_LOW)
+               if (of_flags & OF_GPIO_OPEN_DRAIN)
                        *flags |= GPIO_OPEN_DRAIN;
                else
                        *flags |= GPIO_OPEN_SOURCE;

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index c788b55dfe85079f4a6ef0e7fbf82fc2c20842ae..d11eb2abfced13e11add2baaae2fca2c1549d68b 100644 (file)
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -3340,6 +3340,7 @@ struct gpio_desc *fwnode_get_named_gpiod(struct fwnode_handle *fwnode,
        unsigned long lflags = 0;
        bool active_low = false;
        bool single_ended = false;
+       bool open_drain = false;
        int ret;
 
        if (!fwnode)
@@ -3353,6 +3354,7 @@ struct gpio_desc *fwnode_get_named_gpiod(struct fwnode_handle *fwnode,
                if (!IS_ERR(desc)) {
                        active_low = flags & OF_GPIO_ACTIVE_LOW;
                        single_ended = flags & OF_GPIO_SINGLE_ENDED;
+                       open_drain = flags & OF_GPIO_OPEN_DRAIN;
                }
        } else if (is_acpi_node(fwnode)) {
                struct acpi_gpio_info info;
@@ -3373,7 +3375,7 @@ struct gpio_desc *fwnode_get_named_gpiod(struct fwnode_handle *fwnode,
                lflags |= GPIO_ACTIVE_LOW;
 
        if (single_ended) {
-               if (active_low)
+               if (open_drain)
                        lflags |= GPIO_OPEN_DRAIN;
                else
                        lflags |= GPIO_OPEN_SOURCE;

diff --git a/include/dt-bindings/gpio/gpio.h b/include/dt-bindings/gpio/gpio.h
index c673d2c87c604ae86fc6bfd523a580308752148a..b4f54da694eb4a65ecff5a6a34c3ed2db1c088db 100644 (file)
--- a/include/dt-bindings/gpio/gpio.h
+++ b/include/dt-bindings/gpio/gpio.h
@@ -17,11 +17,15 @@
 #define GPIO_PUSH_PULL 0
 #define GPIO_SINGLE_ENDED 2
 
+/* Bit 2 express Open drain or open source */
+#define GPIO_LINE_OPEN_SOURCE 0
+#define GPIO_LINE_OPEN_DRAIN 4
+
 /*
- * Open Drain/Collector is the combination of single-ended active low,
- * Open Source/Emitter is the combination of single-ended active high.
+ * Open Drain/Collector is the combination of single-ended open drain interface.
+ * Open Source/Emitter is the combination of single-ended open source interface.
  */
-#define GPIO_OPEN_DRAIN (GPIO_SINGLE_ENDED | GPIO_ACTIVE_LOW)
-#define GPIO_OPEN_SOURCE (GPIO_SINGLE_ENDED | GPIO_ACTIVE_HIGH)
+#define GPIO_OPEN_DRAIN (GPIO_SINGLE_ENDED | GPIO_LINE_OPEN_DRAIN)
+#define GPIO_OPEN_SOURCE (GPIO_SINGLE_ENDED | GPIO_LINE_OPEN_SOURCE)
 
 #endif

diff --git a/include/linux/of_gpio.h b/include/linux/of_gpio.h
index 3f87ea5b8bee24d0e5cfa78517cfaf338a2bf051..1e089d5a182beb076d9021e41ab9672820dcfb82 100644 (file)
--- a/include/linux/of_gpio.h
+++ b/include/linux/of_gpio.h
@@ -30,6 +30,7 @@ struct device_node;
 enum of_gpio_flags {
        OF_GPIO_ACTIVE_LOW = 0x1,
        OF_GPIO_SINGLE_ENDED = 0x2,
+       OF_GPIO_OPEN_DRAIN = 0x4,
 };
 
 #ifdef CONFIG_OF_GPIO