To define the initial state of a given gpio you can add a gpio-init node
to a gpio controller. This doesn't prevent a later consumer to request
that pin and only defines a save initial state.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
---
drivers/gpio/gpiolib.c | 43 ++++++++++++++++++++++++++++++-------------
1 file changed, 30 insertions(+), 13 deletions(-)
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index de543fbb1321..4aeba5193726 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -260,13 +260,12 @@ int gpio_direction_input(unsigned gpio)
}
EXPORT_SYMBOL(gpio_direction_input);
-static int gpioinfo_request_one(struct gpio_info *gi, unsigned long flags,
- const char *label)
+static int gpioinfo_configure(struct gpio_info *gi, unsigned long flags)
{
int err;
/*
- * Not all of the flags below are mulit-bit, but, for the sake
+ * Not all of the flags below are multi-bit, but, for the sake
* of consistency, the code is written as if all of them were.
*/
const bool active_low = (flags & GPIOF_ACTIVE_LOW) == GPIOF_ACTIVE_LOW;
@@ -275,10 +274,6 @@ static int gpioinfo_request_one(struct gpio_info *gi, unsigned long flags,
const bool init_active = (flags & GPIOF_INIT_ACTIVE) == GPIOF_INIT_ACTIVE;
const bool init_high = (flags & GPIOF_INIT_HIGH) == GPIOF_INIT_HIGH;
- err = gpioinfo_request(gi, label);
- if (err)
- return err;
-
gi->active_low = active_low;
if (dir_in)
@@ -288,6 +283,19 @@ static int gpioinfo_request_one(struct gpio_info *gi, unsigned long flags,
else
err = gpioinfo_direction_output(gi, init_high);
+ return err;
+}
+
+static int gpioinfo_request_one(struct gpio_info *gi, unsigned long flags,
+ const char *label)
+{
+ int err;
+
+ err = gpioinfo_request(gi, label);
+ if (err)
+ return err;
+
+ err = gpioinfo_configure(gi, flags);
if (err)
gpioinfo_free(gi);
@@ -375,14 +383,15 @@ static int gpiochip_find_base(int start, int ngpio)
return base;
}
-static int of_hog_gpio(struct device_node *np, struct gpio_chip *chip,
- unsigned int idx)
+static int of_hogninit_gpio(struct device_node *np, struct gpio_chip *chip,
+ unsigned int idx, bool request)
{
struct device_node *chip_np = chip->dev->device_node;
unsigned long flags = 0;
u32 gpio_cells, gpio_num, gpio_flags;
int ret, gpio;
const char *name = NULL;
+ struct gpio_info *gi;
ret = of_property_read_u32(chip_np, "#gpio-cells", &gpio_cells);
if (ret)
@@ -417,6 +426,7 @@ static int of_hog_gpio(struct device_node *np, struct gpio_chip *chip,
return ret;
}
+ gi = gpio_to_desc(gpio);
/*
* Note that, in order to be compatible with Linux, the code
@@ -439,9 +449,13 @@ static int of_hog_gpio(struct device_node *np, struct gpio_chip *chip,
else
return -EINVAL;
- of_property_read_string(np, "line-name", &name);
+ if (request) {
+ of_property_read_string(np, "line-name", &name);
- return gpio_request_one(gpio, flags, name);
+ return gpioinfo_request_one(gi, flags, name);
+ } else {
+ return gpioinfo_configure(gi, flags);
+ }
}
static int of_gpiochip_scan_hogs(struct gpio_chip *chip)
@@ -453,12 +467,15 @@ static int of_gpiochip_scan_hogs(struct gpio_chip *chip)
return 0;
for_each_available_child_of_node(chip->dev->device_node, np) {
- if (!of_property_read_bool(np, "gpio-hog"))
+ bool hog = of_property_read_bool(np, "gpio-hog");
+ bool init = of_property_read_bool(np, "gpio-init");
+
+ if (!hog && !init)
continue;
for (ret = 0, i = 0;
!ret;
- ret = of_hog_gpio(np, chip, i), i++)
+ ret = of_hogninit_gpio(np, chip, i, hog), i++)
;
/*
* We ignore -EOVERFLOW because it serves us as an
--
2.11.0
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