Input: sysrq - DT binding for key sequence
Adding a simple device tree binding for the specification of key
sequences. Definition of the keys found in the sequence are located in
'include/uapi/linux/input.h'.
For the sysrq driver, holding the sequence of keys down for a specific
amount of time will reset the system.
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Acked-by: Grant Likely <grant.likely@linaro.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c
index 55ba46f..749dae8 100644
--- a/drivers/tty/sysrq.c
+++ b/drivers/tty/sysrq.c
@@ -45,6 +45,7 @@
#include <linux/moduleparam.h>
#include <linux/jiffies.h>
#include <linux/syscalls.h>
+#include <linux/of.h>
#include <asm/ptrace.h>
#include <asm/irq_regs.h>
@@ -681,6 +682,40 @@
}
}
+#ifdef CONFIG_OF
+static void sysrq_of_get_keyreset_config(void)
+{
+ u32 key;
+ struct device_node *np;
+ struct property *prop;
+ const __be32 *p;
+
+ np = of_find_node_by_path("/chosen/linux,sysrq-reset-seq");
+ if (!np) {
+ pr_debug("No sysrq node found");
+ return;
+ }
+
+ /* Reset in case a __weak definition was present */
+ sysrq_reset_seq_len = 0;
+
+ of_property_for_each_u32(np, "keyset", prop, p, key) {
+ if (key == KEY_RESERVED || key > KEY_MAX ||
+ sysrq_reset_seq_len == SYSRQ_KEY_RESET_MAX)
+ break;
+
+ sysrq_reset_seq[sysrq_reset_seq_len++] = (unsigned short)key;
+ }
+
+ /* Get reset timeout if any. */
+ of_property_read_u32(np, "timeout-ms", &sysrq_reset_downtime_ms);
+}
+#else
+static void sysrq_of_get_keyreset_config(void)
+{
+}
+#endif
+
static void sysrq_reinject_alt_sysrq(struct work_struct *work)
{
struct sysrq_state *sysrq =
@@ -914,6 +949,7 @@
int error;
int i;
+ /* First check if a __weak interface was instantiated. */
for (i = 0; i < ARRAY_SIZE(sysrq_reset_seq); i++) {
key = platform_sysrq_reset_seq[i];
if (key == KEY_RESERVED || key > KEY_MAX)
@@ -922,6 +958,12 @@
sysrq_reset_seq[sysrq_reset_seq_len++] = key;
}
+ /*
+ * DT configuration takes precedence over anything that would
+ * have been defined via the __weak interface.
+ */
+ sysrq_of_get_keyreset_config();
+
error = input_register_handler(&sysrq_handler);
if (error)
pr_err("Failed to register input handler, error %d", error);