Hi Alberto, On Sat, Jan 16, 2010 at 06:48:45PM +0100, Alberto Panizzo wrote: > Version 2 for this driver proposal. > -------------------------------------------------------------------------------- > The MXC family of Application Processors is shipped with a Keypad Port > supported now by this driver. > > The peripheral can control up to an 8x8 matrix key pad where all the scanning > procedure is done via software. > > The hardware provide two interrupts: one for a key pressed (KDI) and one for > all key releases (KRI). There is also a simple circuit for glitch reduction > (said for synchronization) made by two series of 3 D-latches clocked by the > keypad-clock that stabilize the interrupts sources. > KDI and KRI are fired only if the respective conditions are maintained for at > last 4 keypad-clock cycle. > > Those simple synchronization circuits are used also for multiple key pressures: > between a KDI and a KRI the driver reset the sync circuit and re-enable the KDI > interrupt so after 3 keypad-clock cycle another KDI is fired making possible to > repeat the matrix scan operation. > Nicely looking driver, thank you. > This algorithm is done via a threaded management of the keypad interrupt source > and delayed by a proper (and longer) debounce interval controlled by the > platform initialization. This I am not so sure about - the core of the matrix scan routine does not sleep so I wonder if starting a separate thread is not too wasteful in this case - you can easily do whan you want with a timer, no? > + > + /* > + * Search for rows and cols enabled > + */ > + keymap_data = (struct matrix_keymap_data *) pdata->keymap_data; Why do you need to cast away constness instead of declaring keymap_data as const pointer? -- Dmitry -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
