@@ -475,6 +475,73 @@ static int linehandle_validate_flags(u32 flags)
return 0;
}
+static void linehandle_configure_flag(unsigned long *flagsp,
+ u32 bit, bool active)
+{
+ if (active)
+ set_bit(bit, flagsp);
+ else
+ clear_bit(bit, flagsp);
+}
+
+static long linehandle_set_config(struct linehandle_state *lh,
+ void __user *ip)
+{
+ struct gpiohandle_config gcnf;
+ struct gpio_desc *desc;
+ int i, ret;
+ u32 lflags;
+ unsigned long *flagsp;
+
+ if (copy_from_user(&gcnf, ip, sizeof(gcnf)))
+ return -EFAULT;
+
+ lflags = gcnf.flags;
+ ret = linehandle_validate_flags(lflags);
+ if (ret)
+ return ret;
+
+ for (i = 0; i < lh->numdescs; i++) {
+ desc = lh->descs[i];
+ flagsp = &desc->flags;
+
+ linehandle_configure_flag(flagsp, FLAG_ACTIVE_LOW,
+ lflags & GPIOHANDLE_REQUEST_ACTIVE_LOW);
+
+ linehandle_configure_flag(flagsp, FLAG_OPEN_DRAIN,
+ lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN);
+
+ linehandle_configure_flag(flagsp, FLAG_OPEN_SOURCE,
+ lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE);
+
+ linehandle_configure_flag(flagsp, FLAG_PULL_UP,
+ lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP);
+
+ linehandle_configure_flag(flagsp, FLAG_PULL_DOWN,
+ lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN);
+
+ linehandle_configure_flag(flagsp, FLAG_BIAS_DISABLE,
+ lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE);
+
+ /*
+ * Lines have to be requested explicitly for input
+ * or output, else the line will be treated "as is".
+ */
+ if (lflags & GPIOHANDLE_REQUEST_OUTPUT) {
+ int val = !!gcnf.default_values[i];
+
+ ret = gpiod_direction_output(desc, val);
+ if (ret)
+ return ret;
+ } else if (lflags & GPIOHANDLE_REQUEST_INPUT) {
+ ret = gpiod_direction_input(desc);
+ if (ret)
+ return ret;
+ }
+ }
+ return 0;
+}
+
static long linehandle_ioctl(struct file *filep, unsigned int cmd,
unsigned long arg)
{
@@ -525,6 +592,8 @@ static long linehandle_ioctl(struct file *filep, unsigned int cmd,
lh->descs,
NULL,
vals);
+ } else if (cmd == GPIOHANDLE_SET_CONFIG_IOCTL) {
+ return linehandle_set_config(lh, ip);
}
return -EINVAL;
}
@@ -100,6 +100,24 @@ struct gpiohandle_request {
int fd;
};
+/**
+ * struct gpiohandle_config - Configuration for a GPIO handle request
+ * @flags: updated flags for the requested GPIO lines, such as
+ * GPIOHANDLE_REQUEST_OUTPUT, GPIOHANDLE_REQUEST_ACTIVE_LOW etc, OR:ed
+ * together
+ * @default_values: if the GPIOHANDLE_REQUEST_OUTPUT is set in flags,
+ * this specifies the default output value, should be 0 (low) or
+ * 1 (high), anything else than 0 or 1 will be interpreted as 1 (high)
+ * @padding: reserved for future use and should be zero filled
+ */
+struct gpiohandle_config {
+ __u32 flags;
+ __u8 default_values[GPIOHANDLES_MAX];
+ __u32 padding[4]; /* padding for future use */
+};
+
+#define GPIOHANDLE_SET_CONFIG_IOCTL _IOWR(0xB4, 0x0a, struct gpiohandle_config)
+
/**
* struct gpiohandle_data - Information of values on a GPIO handle
* @values: when getting the state of lines this contains the current
Add the GPIOHANDLE_SET_CONFIG_IOCTL to the gpio chardev. The ioctl allows some of the configuration of a requested handle to be changed without having to release the line. The primary use case is the changing of direction for bi-directional lines. Based on initial work by Bartosz Golaszewski <bgolaszewski@baylibre.com> Signed-off-by: Kent Gibson <warthog618@gmail.com> --- drivers/gpio/gpiolib.c | 68 +++++++++++++++++++++++++++++++++++++++ include/uapi/linux/gpio.h | 18 +++++++++++ 2 files changed, 86 insertions(+)