Re: [PATCH v2 2/5] Input: atkbd: Expose function row physical map to userspace

Rajat Jain
2020-03-26T22:19:25Z

On Thu, Mar 26, 2020 at 2:27 PM Dmitry Torokhov
<dmitry.torokhov@gmail.com> wrote:
>
> On Tue, Mar 24, 2020 at 05:35:15AM -0700, Rajat Jain wrote:
> > Certain keyboards have their top-row keys intended
> > for actions such as "Browser back", "Browser Refresh", "Fullscreen"
> > etc as their primary mode, thus they will send physical codes for those
> > actions. Further, they don't have a dedicated "Fn" key so don't have
> > the capability to generate function key codes (e.g. F1, F2 etc..).
> > However in this case, if userspace still wants to "synthesize" those
> > function keys using the top row action keys, it needs to know the
> > physical position of the top row keys. (Essentially a mapping between
> > usage codes and a physical location in the top row).
> >
> > This patch enhances the atkbd driver to receive such a mapping from the
> > firmware / device tree, and expose it to userspace in the form of
> > a function-row-physmap attribute. The attribute would be a space
> > separated ordered list of physical codes, for the keys in the function
> > row, in left-to-right order.
> >
> > The attribute will only be present if the kernel knows about such
> > mapping, otherwise the attribute shall not be visible.
> >
> > Signed-off-by: Rajat Jain <rajatja@google.com>
> > ---
> > v2: Remove the Change-Id from the commit log
> >
> > drivers/input/keyboard/atkbd.c | 59 ++++++++++++++++++++++++++++++++++
> > 1 file changed, 59 insertions(+)
> >
> > diff --git a/drivers/input/keyboard/atkbd.c b/drivers/input/keyboard/atkbd.c
> > index 7e3eae54c1926..7623eebef2593 100644
> > --- a/drivers/input/keyboard/atkbd.c
> > +++ b/drivers/input/keyboard/atkbd.c
> > @@ -24,6 +24,7 @@
> > #include <linux/libps2.h>
> > #include <linux/mutex.h>
> > #include <linux/dmi.h>
> > +#include <linux/property.h>
> >
> > #define DRIVER_DESC "AT and PS/2 keyboard driver"
> >
> > @@ -63,6 +64,8 @@ static bool atkbd_terminal;
> > module_param_named(terminal, atkbd_terminal, bool, 0);
> > MODULE_PARM_DESC(terminal, "Enable break codes on an IBM Terminal keyboard connected via AT/PS2");
> >
> > +#define MAX_FUNCTION_ROW_KEYS 24
> > +
> > /*
> > * Scancode to keycode tables. These are just the default setting, and
> > * are loadable via a userland utility.
> > @@ -230,6 +233,9 @@ struct atkbd {
> >
> > /* Serializes reconnect(), attr->set() and event work */
> > struct mutex mutex;
> > +
> > + u16 function_row_physmap[MAX_FUNCTION_ROW_KEYS];
> > + int num_function_row_keys;
> > };
> >
> > /*
> > @@ -283,6 +289,7 @@ static struct device_attribute atkbd_attr_##_name = \
> > __ATTR(_name, S_IRUGO, atkbd_do_show_##_name, NULL);
> >
> > ATKBD_DEFINE_RO_ATTR(err_count);
> > +ATKBD_DEFINE_RO_ATTR(function_row_physmap);
> >
> > static struct attribute *atkbd_attributes[] = {
> > &atkbd_attr_extra.attr,
> > @@ -292,11 +299,42 @@ static struct attribute *atkbd_attributes[] = {
> > &atkbd_attr_softrepeat.attr,
> > &atkbd_attr_softraw.attr,
> > &atkbd_attr_err_count.attr,
> > + &atkbd_attr_function_row_physmap.attr,
> > NULL
> > };
> >
> > +static ssize_t atkbd_show_function_row_physmap(struct atkbd *atkbd, char *buf)
> > +{
> > + ssize_t size = 0;
> > + int i;
> > +
> > + if (!atkbd->num_function_row_keys)
> > + return 0;
> > +
> > + for (i = 0; i < atkbd->num_function_row_keys; i++)
> > + size += sprintf(buf + size, "%02X ",
> > + atkbd->function_row_physmap[i]);
> > + size += sprintf(buf + size, "\n");
> > + return size;
> > +}
> > +
> > +static umode_t atkbd_attr_is_visible(struct kobject *kobj,
> > + struct attribute *attr, int i)
> > +{
> > + struct device *dev = container_of(kobj, struct device, kobj);
> > + struct serio *serio = to_serio_port(dev);
> > + struct atkbd *atkbd = serio_get_drvdata(serio);
> > +
> > + if (attr == &atkbd_attr_function_row_physmap.attr &&
> > + !atkbd->num_function_row_keys)
> > + return 0;
> > +
> > + return attr->mode;
> > +}
> > +
> > static struct attribute_group atkbd_attribute_group = {
> > .attrs = atkbd_attributes,
> > + .is_visible = atkbd_attr_is_visible,
> > };
> >
> > static const unsigned int xl_table[] = {
> > @@ -1121,6 +1159,25 @@ static void atkbd_set_device_attrs(struct atkbd *atkbd)
> > }
> > }
> >
> > +static void atkbd_parse_fwnode_data(struct serio *serio)
> > +{
> > + struct atkbd *atkbd = serio_get_drvdata(serio);
> > + struct device *dev = &serio->dev;
> > + int n;
> > +
> > + if (!dev_fwnode(dev))
> > + return;
>
> I do not think we need this guard.

Done.

>
> > +
> > + /* Parse "function-row-physmap" property */
> > + n = device_property_count_u16(dev, "function-row-physmap");
> > + if (n > 0 && n <= MAX_FUNCTION_ROW_KEYS &&
> > + !device_property_read_u16_array(dev, "function-row-physmap",
> > + atkbd->function_row_physmap, n)) {
> > + atkbd->num_function_row_keys = n;
> > + dev_info(dev, "FW reported %d function-row key locations\n", n);
>
> dev_dbg().

Done.

>
> > + }
> > +}
> > +
> > /*
> > * atkbd_connect() is called when the serio module finds an interface
> > * that isn't handled yet by an appropriate device driver. We check if
> > @@ -1184,6 +1241,8 @@ static int atkbd_connect(struct serio *serio, struct serio_driver *drv)
> > atkbd->id = 0xab00;
> > }
> >
> > + atkbd_parse_fwnode_data(serio);
> > +
> > atkbd_set_keycode_table(atkbd);
> > atkbd_set_device_attrs(atkbd);
> >
> > --
> > 2.25.1.696.g5e7596f4ac-goog
> >
>
> --
> Dmitry