On 15 July 2013 20:43, Rob Herring <robherri...@gmail.com> wrote: > On 07/15/2013 10:36 AM, mathieu.poir...@linaro.org wrote: > > From: "Mathieu J. Poirier" <mathieu.poir...@linaro.org> > > > > 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.poir...@linaro.org> > > --- > > changes for v4: > > - Moved seach of reset sequence nodes to a single call. > > --- > > .../devicetree/bindings/input/input-reset.txt | 34 ++++++++++++++ > > drivers/tty/sysrq.c | 54 > ++++++++++++++++++++++ > > 2 files changed, 88 insertions(+) > > create mode 100644 > Documentation/devicetree/bindings/input/input-reset.txt > > > > diff --git a/Documentation/devicetree/bindings/input/input-reset.txt > b/Documentation/devicetree/bindings/input/input-reset.txt > > new file mode 100644 > > index 0000000..79504af > > --- /dev/null > > +++ b/Documentation/devicetree/bindings/input/input-reset.txt > > @@ -0,0 +1,34 @@ > > +Input: sysrq reset sequence > > + > > +A simple binding to represent a set of keys as described in > > +include/uapi/linux/input.h. This is to communicate a > > +sequence of keys to the sysrq driver. Upon holding the keys > > +for a specified amount of time (if specified) the system is > > +sync'ed and reset. > > + > > +Key sequences are global to the system but all the keys in a > > +set must be coming from the same input device. > > + > > +The /chosen node should contain a 'linux,sysrq-reset-seq' child > > +node to define a set of keys. > > + > > +Required property: > > +sysrq-reset-seq: array of keycodes > > + > > +Optional property: > > +timeout-ms: duration keys must be pressed together in microseconds > > milliseconds (ms) or microseconds (us)? > > Right, milliseconds.
> > +before generating a sysrq > > + > > +Example: > > + > > + chosen { > > + linux,sysrq-reset-seq { > > + keyset = <0x03 > > + 0x04 > > + 0x0a>; > > + timeout-ms = <3000>; > > + }; > > + }; > > + > > +Would represent KEY_2, KEY_3 and KEY_9. > > + > > diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c > > index b51c154..01a8729 100644 > > --- a/drivers/tty/sysrq.c > > +++ b/drivers/tty/sysrq.c > > @@ -44,6 +44,7 @@ > > #include <linux/uaccess.h> > > #include <linux/moduleparam.h> > > #include <linux/jiffies.h> > > +#include <linux/of.h> > > > > #include <asm/ptrace.h> > > #include <asm/irq_regs.h> > > @@ -671,6 +672,50 @@ static void sysrq_detect_reset_sequence(struct > sysrq_state *state, > > } > > } > > > > +static void sysrq_of_get_keyreset_config(void) > > +{ > > + unsigned short key; > > + struct device_node *np; > > + const struct property *prop; > > + const __be32 *val; > > + int count, i; > > + > > + np = of_find_node_by_path("/chosen/linux,sysrq-reset-seq"); > > + if (!np) { > > + pr_debug("No sysrq node found"); > > + goto out; > > + } > > + > > + prop = of_find_property(np, "keyset", NULL); > > + if (!prop || !prop->value) { > > + pr_err("Invalid input keyset"); > > + goto out; > > + } > > + > > + count = prop->length / sizeof(u32); > > + val = prop->value; > > None of the existing helpers to retrieve property arrays doesn't work here? > The problem here is that we never know how long the sequence will be. As such the 'of_property_read_uXY_array' functions won't work. Or maybe you're referring to another set of helpers... If so, please clarify. > > > + > > + if (count > SYSRQ_KEY_RESET_MAX) > > + count = SYSRQ_KEY_RESET_MAX; > > + > > + /* reset in case a __weak definition was present */ > > + sysrq_reset_seq_len = 0; > > + > > + for (i = 0; i < count; i++) { > > + key = (unsigned short)be32_to_cpup(val++); > > + if (key == KEY_RESERVED || key > KEY_MAX) > > + break; > > + > > + sysrq_reset_seq[sysrq_reset_seq_len++] = key; > > + } > > + > > + /* get reset timeout if any */ > > + of_property_read_u32(np, "timeout-ms", &sysrq_reset_downtime_ms); > > + > > + out: > > + ; > > +} > > + > > static void sysrq_reinject_alt_sysrq(struct work_struct *work) > > { > > struct sysrq_state *sysrq = > > @@ -688,6 +733,7 @@ static void sysrq_reinject_alt_sysrq(struct > work_struct *work) > > input_inject_event(handle, EV_KEY, KEY_SYSRQ, 1); > > input_inject_event(handle, EV_SYN, SYN_REPORT, 1); > > > > + > > spurious ws change > > input_inject_event(handle, EV_KEY, KEY_SYSRQ, 0); > > input_inject_event(handle, EV_KEY, alt_code, 0); > > input_inject_event(handle, EV_SYN, SYN_REPORT, 1); > > @@ -903,6 +949,7 @@ static inline void sysrq_register_handler(void) > > 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) > > @@ -911,6 +958,13 @@ static inline void sysrq_register_handler(void) > > 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); > > > >
_______________________________________________ devicetree-discuss mailing list devicetree-discuss@lists.ozlabs.org https://lists.ozlabs.org/listinfo/devicetree-discuss