@@ -16,6 +16,7 @@
#include <linux/kernel.h>
#include <linux/kfifo.h>
#include <linux/module.h>
+#include <linux/mutex.h>
#include <linux/pinctrl/consumer.h>
#include <linux/poll.h>
#include <linux/spinlock.h>
@@ -423,6 +424,8 @@ struct line {
* @seqno: the sequence number for edge events generated on all lines in
* this line request. Note that this is not used when @num_lines is 1, as
* the line_seqno is then the same and is cheaper to calculate.
+ * @config_mutex: mutex for serializing ioctl() calls to ensure consistency
+ * of configuration, particularly multi-step accesses to desc flags.
* @lines: the lines held by this line request, with @num_lines elements.
*/
struct linereq {
@@ -432,6 +435,7 @@ struct linereq {
wait_queue_head_t wait;
DECLARE_KFIFO_PTR(events, struct gpio_v2_line_event);
atomic_t seqno;
+ struct mutex config_mutex;
struct line lines[];
};
@@ -693,6 +697,29 @@ static int gpio_v2_line_config_validate(struct gpio_v2_line_config *lc,
return 0;
}
+static int gpio_v2_line_config_change_validate(struct linereq *lr,
+ struct gpio_v2_line_config *lc)
+{
+ unsigned int i;
+ u64 flags;
+
+ for (i = 0; i < lr->num_lines; i++) {
+ flags = gpio_v2_line_config_flags(lc, i);
+ /* disallow edge detection changes */
+ if (lr->lines[i].eflags != (flags & GPIO_V2_LINE_EDGE_FLAGS))
+ return -EINVAL;
+
+ if (lr->lines[i].eflags & GPIO_V2_LINE_EDGE_FLAGS) {
+ /* disallow polarity changes */
+ if (test_bit(FLAG_ACTIVE_LOW,
+ &lr->lines[i].desc->flags) !=
+ ((flags & GPIO_V2_LINE_FLAG_ACTIVE_LOW) != 0))
+ return -EINVAL;
+ }
+ }
+ return 0;
+}
+
static void gpio_v2_line_config_flags_to_desc_flags(u64 flags,
unsigned long *flagsp)
{
@@ -772,6 +799,68 @@ static long linereq_get_values(struct linereq *lr, void __user *ip)
return 0;
}
+static long linereq_set_config_unlocked(struct linereq *lr,
+ struct gpio_v2_line_config *lc)
+{
+ struct gpio_desc *desc;
+ unsigned int i;
+ u64 flags;
+ int ret;
+
+ ret = gpio_v2_line_config_change_validate(lr, lc);
+ if (ret)
+ return ret;
+
+ for (i = 0; i < lr->num_lines; i++) {
+ desc = lr->lines[i].desc;
+ flags = gpio_v2_line_config_flags(lc, i);
+
+ gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags);
+ /*
+ * Lines have to be requested explicitly for input
+ * or output, else the line will be treated "as is".
+ */
+ if (flags & GPIO_V2_LINE_FLAG_OUTPUT) {
+ int val = gpio_v2_line_config_output_value(lc, i);
+
+ edge_detector_stop(&lr->lines[i]);
+ ret = gpiod_direction_output(desc, val);
+ if (ret)
+ return ret;
+ } else if (flags & GPIO_V2_LINE_FLAG_INPUT) {
+ ret = gpiod_direction_input(desc);
+ if (ret)
+ return ret;
+ }
+
+ blocking_notifier_call_chain(&desc->gdev->notifier,
+ GPIO_V2_LINE_CHANGED_CONFIG,
+ desc);
+ }
+ return 0;
+}
+
+static long linereq_set_config(struct linereq *lr, void __user *ip)
+{
+ struct gpio_v2_line_config lc;
+ int ret;
+
+ if (copy_from_user(&lc, ip, sizeof(lc)))
+ return -EFAULT;
+
+ ret = gpio_v2_line_config_validate(&lc, lr->num_lines);
+ if (ret)
+ return ret;
+
+ mutex_lock(&lr->config_mutex);
+
+ ret = linereq_set_config_unlocked(lr, &lc);
+
+ mutex_unlock(&lr->config_mutex);
+
+ return ret;
+}
+
static long linereq_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
@@ -780,6 +869,8 @@ static long linereq_ioctl(struct file *file, unsigned int cmd,
if (cmd == GPIO_V2_LINE_GET_VALUES_IOCTL)
return linereq_get_values(lr, ip);
+ else if (cmd == GPIO_V2_LINE_SET_CONFIG_IOCTL)
+ return linereq_set_config(lr, ip);
return -EINVAL;
}
@@ -946,6 +1037,7 @@ static int linereq_create(struct gpio_device *gdev, void __user *ip)
}
}
+ mutex_init(&lr->config_mutex);
init_waitqueue_head(&lr->wait);
if (has_edge_detection) {
size = ulr.event_buffer_size;
Add support for GPIO_V2_LINE_SET_CONFIG_IOCTL, the uAPI v2 line set config ioctl. Signed-off-by: Kent Gibson <warthog618@gmail.com> --- drivers/gpio/gpiolib-cdev.c | 92 +++++++++++++++++++++++++++++++++++++ 1 file changed, 92 insertions(+)