@@ -17,6 +17,11 @@
#include "gpiolib.h"
#include "gpiolib-swnode.h"
+const struct software_node swnode_gpio_undefined = {
+ .name = "gpio-internal-undefined",
+};
+EXPORT_SYMBOL_GPL(swnode_gpio_undefined);
+
static void swnode_format_propname(const char *con_id, char *propname,
size_t max_size)
{
@@ -40,6 +45,9 @@ static struct gpio_device *swnode_get_gpio_device(struct fwnode_handle *fwnode)
if (!gdev_node || !gdev_node->name)
return ERR_PTR(-EINVAL);
+ if (!strcmp(gdev_node->name, "gpio-internal-undefined"))
+ return ERR_PTR(-ENOENT);
+
gdev = gpio_device_find_by_label(gdev_node->name);
return gdev ?: ERR_PTR(-EPROBE_DEFER);
}
@@ -4892,8 +4892,17 @@ DEFINE_SEQ_ATTRIBUTE(gpiolib);
static int __init gpiolib_debugfs_init(void)
{
+ int ret;
+
+ ret = software_node_register(&swnode_gpio_undefined);
+ if (ret < 0) {
+ pr_err("gpiolib: failed to register swnode: %d\n", ret);
+ return ret;
+ }
+
/* /sys/kernel/debug/gpio */
debugfs_create_file("gpio", 0444, NULL, NULL, &gpiolib_fops);
+
return 0;
}
subsys_initcall(gpiolib_debugfs_init);
@@ -12,6 +12,8 @@ struct fwnode_handle;
struct gpio_array;
struct gpio_desc;
+struct software_node;
+
/**
* struct gpio_descs - Struct containing an array of descriptors that can be
* obtained using gpiod_get_array()
@@ -54,6 +56,8 @@ enum gpiod_flags {
GPIOD_OUT_HIGH_OPEN_DRAIN = GPIOD_OUT_HIGH | GPIOD_FLAGS_BIT_OPEN_DRAIN,
};
+extern const struct software_node swnode_gpio_undefined;
+
#ifdef CONFIG_GPIOLIB
/* Return the number of GPIOs associated with a device / function */
SPI devices can specify a cs-gpios property to enumerate their chip selects. Under device tree, a zero entry in this property can be used to specify that a particular chip select is using the SPI controllers native chip select, for example: cs-gpios = <&gpio1 0 0>, <0>; Here the second chip select is native. However, when using swnodes there is currently no way to specify a native chip select. The proposal here is to register a swnode_gpio_undefined software node, that can be specified to allow the indication of a native chip select. For example: static const struct software_node_ref_args device_cs_refs[] = { { .node = &device_gpiochip_swnode, .nargs = 2, .args = { 0, GPIO_ACTIVE_LOW }, }, { .node = &swnode_gpio_undefined, .nargs = 0, }, }; Register the swnode as the gpiolib is initialised and check in swnode_get_gpio_device if the returned node matches swnode_gpio_undefined and return -ENOENT, which matches the behaviour of the device tree system when it encounters a 0 phandle. Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com> --- No changes since v1. Thanks, Charles drivers/gpio/gpiolib-swnode.c | 8 ++++++++ drivers/gpio/gpiolib.c | 9 +++++++++ include/linux/gpio/consumer.h | 4 ++++ 3 files changed, 21 insertions(+)