Re: [PATCH V1] input: keyboard: Add interrupt keyboard driver.
From: Laxman Dewangan <ldewangan@nvidia.com>
Date: 2012-01-26 02:12:12
On Thursday 19 January 2012 01:09 PM, Laxman Dewangan wrote:
On Thursday, January 19, 2012 1:00 PM, Dmitry Torokhov wrote:quoted
On Tue, Jan 17, 2012 at 11:11:55AM +0530, Laxman Dewangan wrote:quoted
This driver enables the key detection of the keys which are connected to interrupt lines. Each key is capable of generating an interrupt, and the statesi (pressed or released) cannot be found by any mechanism. A key press event generated when interrupt occurs, and based on the debounce time setting, a key release event is generated. There is no need to read the state of the keys.Is it possible to modify gpio_keys to skip requesting and settin up certain gpios and and use it instead of a brand new driver?I first tried this approach and found that this makes the gpio_keys driver very complex because almost all places where gpio-apis are getting called need to put under if condition. Also there is some special handling for auto key release events Which makes gpio-key driver again complex.
Hi Dmitry, Do you have any further comment on above approach? Here is little bit background which can help on understanding. I am working on some MFD devices and to tried to support the onkey from single driver to avoid having driver for each mfd-pmic driver. When developing this driver, I though of following behaviors of the pmic device for power-btn/onkey switches: 1. Separate Interrupt for press and release: (Falling and rising interrupt, no level interrupt) So two different interrupt will get registered and based on interrupt number the key code and key value will get reported to input system. Device like AB8500 (ab8500-ponkey.c). 2. Generates interrupt for only key press, no interrupt for the key release (only one interrupt i.e. Falling edge) In this case, it need to send the release event automatically after sending press event. So whenever there is falling edge on keys, the interrupt get generated, No interrupt on pressed level. Devices like ricoh583, max77663. 3. Keep generating interrupt if key is pressed but no interrupt after release (Kind on level (low) interrupt and so multiple interrupts till key pressed.) Devices like tps65910.. In this case, the device generates level interrupt and if it acked, again generates interrupt. So if we send the key press/release together without waiting, we will endup with sending the key event multiple time. To avoid this I used the debaince logic as follows: detect first interrupt, send press event and start timer and wait for timer to expire for sending release events. If interrupt again occurs before timer expires, restart timer again. Keep doing this until user release the key. Once he release the key, there will be no interrupt and so timer will be expire after some time i.e. debounce time and then report key released.
quoted
-- Dmitry