From 277d358eda7f7571450e09c615c8aaf67d7b4693 Mon Sep 17 00:00:00 2001 From: Amaury Pouly Date: Tue, 18 Jun 2013 16:43:27 +0200 Subject: imx233: add generic lradc based button driver This driver does debouncing and best lradc usage and only requires a sorted table of values to work, this factoring code as much as possible. Change-Id: I84b46f4b08094634e1c5deb5ca9ba20763389e66 --- firmware/target/arm/imx233/button-lradc-imx233.c | 122 +++++++++++++++++++++++ firmware/target/arm/imx233/button-lradc-imx233.h | 56 +++++++++++ 2 files changed, 178 insertions(+) create mode 100644 firmware/target/arm/imx233/button-lradc-imx233.c create mode 100644 firmware/target/arm/imx233/button-lradc-imx233.h (limited to 'firmware/target/arm/imx233') diff --git a/firmware/target/arm/imx233/button-lradc-imx233.c b/firmware/target/arm/imx233/button-lradc-imx233.c new file mode 100644 index 0000000000..66d42a47dc --- /dev/null +++ b/firmware/target/arm/imx233/button-lradc-imx233.c @@ -0,0 +1,122 @@ +/*************************************************************************** + * __________ __ ___. + * Open \______ \ ____ ____ | | _\_ |__ _______ ___ + * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ / + * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < < + * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \ + * \/ \/ \/ \/ \/ + * $Id$ + * + * Copyright (C) 2013 by Amaury Pouly + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY + * KIND, either express or implied. + * + ****************************************************************************/ +#include "button-lradc-imx233.h" +#include "stdlib.h" +#include "lradc-imx233.h" + +#ifndef IMX233_BUTTON_LRADC_CHANNEL +#error You must define IMX233_BUTTON_LRADC_CHANNEL to use button-lradc +#endif + +/* physical channel */ +#define CHAN IMX233_BUTTON_LRADC_CHANNEL +/* number of irq per second */ +#ifdef IMX233_BUTTON_LRADC_RATE +# define RATE IMX233_BUTTON_LRADC_RATE +#else +# define RATE HZ +#endif +/* number of samples per irq */ +#ifdef IMX233_BUTTON_LRADC_SAMPLES +# define SAMPLES IMX233_BUTTON_LRADC_SAMPLES +#else +# define SAMPLES 10 +#endif +/* delay's delay */ +#define DELAY (LRADC_DELAY_FREQ / RATE / SAMPLES) + +static int button_delay; +static int button_chan; +static int button_val[2]; +static int button_idx; +static int button_mask; +static int table_size; + +static int button_find(int val) +{ + // shortcuts + struct imx233_button_lradc_mapping_t *table = imx233_button_lradc_mapping; + /* FIXME use a dichotomy */ + int i = 0; + while(i < table_size && val >= table[i].adc_val) + i++; + // extreme cases + int btn = 0; + // if i=n then choose i-1 and otherwise choose best between i-1 and i + if(i == 0) + btn = table[0].btn; + else if(i == table_size) + btn = table[i - 1].btn; + // choose best between i-1 and i (note that table[i-1]<=val<=table[i]) */ + else if(val - table[i - 1].adc_val < table[i].adc_val - val) + btn = table[i - 1].btn; + else + btn = table[i].btn; + return btn; +} + +int button_value; + +static void button_lradc_irq(int chan) +{ + (void) chan; + /* read value, kick channel */ + button_val[button_idx] = imx233_lradc_read_channel(button_chan) / SAMPLES; + imx233_lradc_clear_channel(button_chan); + imx233_lradc_setup_channel(button_chan, true, true, SAMPLES - 1, LRADC_SRC(CHAN)); + imx233_lradc_setup_delay(button_delay, 1 << button_chan, 0, SAMPLES - 1, DELAY); + imx233_lradc_kick_delay(button_delay); + button_value = button_val[button_idx]; + /* compute mask, compare to previous one */ + button_val[button_idx] = button_find(button_val[button_idx]); + button_idx = 1 - button_idx; + if(button_val[0] == button_val[1]) + button_mask = button_val[0]; +} + +void imx233_button_lradc_init(void) +{ + button_chan = imx233_lradc_acquire_channel(LRADC_SRC(CHAN), TIMEOUT_NOBLOCK); + if(button_chan < 0) + panicf("Cannot get channel for button-lradc"); + button_delay = imx233_lradc_acquire_delay(TIMEOUT_NOBLOCK); + if(button_delay < 0) + panicf("Cannot get delay for button-lradc"); + imx233_lradc_setup_channel(button_chan, true, true, SAMPLES - 1, LRADC_SRC(CHAN)); + imx233_lradc_setup_delay(button_delay, 1 << button_chan, 0, SAMPLES - 1, DELAY); + imx233_lradc_enable_channel_irq(button_chan, true); + imx233_lradc_set_channel_irq_callback(button_chan, button_lradc_irq); + imx233_lradc_kick_delay(button_delay); + + table_size = 0; + while(imx233_button_lradc_mapping[table_size].btn != IMX233_BUTTON_LRADC_END) + table_size++; +} + +bool imx233_button_lradc_hold(void) +{ + return button_mask == IMX233_BUTTON_LRADC_HOLD; +} + +int imx233_button_lradc_read(void) +{ + return button_mask == IMX233_BUTTON_LRADC_HOLD ? 0 : button_mask; +} diff --git a/firmware/target/arm/imx233/button-lradc-imx233.h b/firmware/target/arm/imx233/button-lradc-imx233.h new file mode 100644 index 0000000000..d3e6ad8326 --- /dev/null +++ b/firmware/target/arm/imx233/button-lradc-imx233.h @@ -0,0 +1,56 @@ +/*************************************************************************** + * __________ __ ___. + * Open \______ \ ____ ____ | | _\_ |__ _______ ___ + * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ / + * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < < + * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \ + * \/ \/ \/ \/ \/ + * $Id$ + * + * Copyright (C) 2013 by Amaury Pouly + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY + * KIND, either express or implied. + * + ****************************************************************************/ +#ifndef __button_lradc_imx233__ +#define __button_lradc_imx233__ + +#include "button.h" +#include "button-target.h" + +/** This driver implements button sensing with lradc. It does debouncing + * and can handle hold sensing too. It can be tweaked using the following defines + * and variables: + * - imx233_button_lradc_mapping: target-defined table of adc values and mapping + * - IMX233_BUTTON_LRADC_CHANNEL: lradc channel to use + */ + +/* special value for btn to handle HOLD */ +#define IMX233_BUTTON_LRADC_END -1 +#define IMX233_BUTTON_LRADC_HOLD -2 + +struct imx233_button_lradc_mapping_t +{ + int adc_val; + int btn; +}; + +/* target-defined + * NOTE for proper operation, the table should contain entries for all states, including: + * - one with adc_val set to default value when no button is pressed + * - one with adc_val set to value when hold is selected (if hold is sensed using adc) + * - a dummy entry with btn set to IMX233_BUTTON_LRADC_END as the last entry + * The table must be sorted by increasing values of adc_val */ +extern struct imx233_button_lradc_mapping_t imx233_button_lradc_mapping[]; + +void imx233_button_lradc_init(void); +int imx233_button_lradc_read(void); +bool imx233_button_lradc_hold(void); + +#endif /* __button_lradc_imx233__ */ -- cgit v1.2.3