gpio: Add new flags to control sleep status of GPIOs

Add new flags to allow users to specify that they are not concerned with
the status of GPIOs whilst in a sleep/low power state.

Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c
index b13b7c7c335f415b6d952fb084250f5c18bfa5e0..e2abf0eabaf880b634b4d5bdfb5c27a9a0be0656 100644 (file)
--- a/drivers/gpio/gpiolib-of.c
+++ b/drivers/gpio/gpiolib-of.c
@@ -153,6 +153,9 @@ struct gpio_desc *of_find_gpio(struct device *dev, const char *con_id,
                        *flags |= GPIO_OPEN_SOURCE;
        }
 
+       if (of_flags & OF_GPIO_SLEEP_MAY_LOOSE_VALUE)
+               *flags |= GPIO_SLEEP_MAY_LOOSE_VALUE;
+
        return desc;
 }
 

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 995ca9cf7dbf8bcbba297d7497c1dd3fcefa2286..c81c42093ff63d32c9d95d6cd39aefb60f45bd49 100644 (file)
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -2869,6 +2869,16 @@ bool gpiochip_line_is_open_source(struct gpio_chip *chip, unsigned int offset)
 }
 EXPORT_SYMBOL_GPL(gpiochip_line_is_open_source);
 
+bool gpiochip_line_is_persistent(struct gpio_chip *chip, unsigned int offset)
+{
+       if (offset >= chip->ngpio)
+               return false;
+
+       return !test_bit(FLAG_SLEEP_MAY_LOOSE_VALUE,
+                        &chip->gpiodev->descs[offset].flags);
+}
+EXPORT_SYMBOL_GPL(gpiochip_line_is_persistent);
+
 /**
  * gpiod_get_raw_value_cansleep() - return a gpio's raw value
  * @desc: gpio whose value will be returned
@@ -3225,6 +3235,8 @@ static int gpiod_configure_flags(struct gpio_desc *desc, const char *con_id,
                set_bit(FLAG_OPEN_DRAIN, &desc->flags);
        if (lflags & GPIO_OPEN_SOURCE)
                set_bit(FLAG_OPEN_SOURCE, &desc->flags);
+       if (lflags & GPIO_SLEEP_MAY_LOOSE_VALUE)
+               set_bit(FLAG_SLEEP_MAY_LOOSE_VALUE, &desc->flags);
 
        /* No particular flag request, return here... */
        if (!(dflags & GPIOD_FLAGS_BIT_DIR_SET)) {

diff --git a/drivers/gpio/gpiolib.h b/drivers/gpio/gpiolib.h
index 2495b7ee1b426969406b60fbb52b8a9fecae6917..f74b8a7632424fb92f81e0106fc3ed1caf2e9c7c 100644 (file)
--- a/drivers/gpio/gpiolib.h
+++ b/drivers/gpio/gpiolib.h
@@ -190,6 +190,7 @@ struct gpio_desc {
 #define FLAG_OPEN_SOURCE 8     /* Gpio is open source type */
 #define FLAG_USED_AS_IRQ 9     /* GPIO is connected to an IRQ */
 #define FLAG_IS_HOGGED 11      /* GPIO is hogged */
+#define FLAG_SLEEP_MAY_LOOSE_VALUE 12  /* GPIO may loose value in sleep */
 
        /* Connection label */
        const char              *label;

diff --git a/include/dt-bindings/gpio/gpio.h b/include/dt-bindings/gpio/gpio.h
index b4f54da694eb4a65ecff5a6a34c3ed2db1c088db..c5074584561d9459db81230a9d7081b30189cac8 100644 (file)
--- a/include/dt-bindings/gpio/gpio.h
+++ b/include/dt-bindings/gpio/gpio.h
@@ -28,4 +28,8 @@
 #define GPIO_OPEN_DRAIN (GPIO_SINGLE_ENDED | GPIO_LINE_OPEN_DRAIN)
 #define GPIO_OPEN_SOURCE (GPIO_SINGLE_ENDED | GPIO_LINE_OPEN_SOURCE)
 
+/* Bit 3 express GPIO suspend/resume persistence */
+#define GPIO_SLEEP_MAINTAIN_VALUE 0
+#define GPIO_SLEEP_MAY_LOOSE_VALUE 8
+
 #endif

diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h
index 393582867afddb17e2969a659bedcb975f710208..af20369ec8e7b573dec63dcf77346ddd75e4e332 100644 (file)
--- a/include/linux/gpio/driver.h
+++ b/include/linux/gpio/driver.h
@@ -213,6 +213,9 @@ bool gpiochip_line_is_irq(struct gpio_chip *chip, unsigned int offset);
 bool gpiochip_line_is_open_drain(struct gpio_chip *chip, unsigned int offset);
 bool gpiochip_line_is_open_source(struct gpio_chip *chip, unsigned int offset);
 
+/* Sleep persistence inquiry for drivers */
+bool gpiochip_line_is_persistent(struct gpio_chip *chip, unsigned int offset);
+
 /* get driver data */
 void *gpiochip_get_data(struct gpio_chip *chip);
 

diff --git a/include/linux/gpio/machine.h b/include/linux/gpio/machine.h
index c0d712d22b079ebc16129ef2618f41762276cf5e..13adadf53c09f3c33da076de181f61e0f16baaa6 100644 (file)
--- a/include/linux/gpio/machine.h
+++ b/include/linux/gpio/machine.h
@@ -9,6 +9,8 @@ enum gpio_lookup_flags {
        GPIO_ACTIVE_LOW = (1 << 0),
        GPIO_OPEN_DRAIN = (1 << 1),
        GPIO_OPEN_SOURCE = (1 << 2),
+       GPIO_SLEEP_MAINTAIN_VALUE = (0 << 3),
+       GPIO_SLEEP_MAY_LOOSE_VALUE = (1 << 3),
 };
 
 /**

diff --git a/include/linux/of_gpio.h b/include/linux/of_gpio.h
index 1e089d5a182beb076d9021e41ab9672820dcfb82..ca10f43564deec18de2f03f225b2e479902976f1 100644 (file)
--- a/include/linux/of_gpio.h
+++ b/include/linux/of_gpio.h
@@ -31,6 +31,7 @@ enum of_gpio_flags {
        OF_GPIO_ACTIVE_LOW = 0x1,
        OF_GPIO_SINGLE_ENDED = 0x2,
        OF_GPIO_OPEN_DRAIN = 0x4,
+       OF_GPIO_SLEEP_MAY_LOOSE_VALUE = 0x8,
 };
 
 #ifdef CONFIG_OF_GPIO