rockbox/firmware/target/arm/imx233/button-lradc-imx233.c
Amaury Pouly 0324bf59a8 imx233: make button-lradc drive able to handle VDDIO derived values
In most devices, the button ladder is not actually derived from VDDIO but
from a constant voltage source, making it very easy to read it. However on
some devices like ther ZEN X-Fi Style, the ladder is wired to VDDIO we
can be changed so it's crucial that the button driver correctly scales the
values wrt VDDIO.

Change-Id: Ifc11abe2838fa7d16d0d60ecd96964a8dc5ea6d7
2014-02-10 23:14:25 +01:00

213 lines
6.8 KiB
C

/***************************************************************************
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* Open \______ \ ____ ____ | | _\_ |__ _______ ___
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* \/ \/ \/ \/ \/
* $Id$
*
* 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 <stdlib.h>
#include "cpu.h"
#include "kernel.h"
#include "button-lradc-imx233.h"
#include "lradc-imx233.h"
#include "pinctrl-imx233.h"
#ifndef IMX233_BUTTON_LRADC_CHANNEL
# error You must define IMX233_BUTTON_LRADC_CHANNEL to use button-lradc
#endif
#if defined(HAS_BUTTON_HOLD) && !defined(IMX233_BUTTON_LRADC_HOLD_DET)
# error You must defined IMX233_BUTTON_LRADC_HOLD_DET if you use hold
#endif
#if defined(IMX233_BUTTON_LRADC_HOLD_DET) && \
IMX233_BUTTON_LRADC_HOLD_DET == BLH_GPIO && \
(!defined(BLH_GPIO_BANK) || !defined(BLH_GPIO_PIN))
# error You must define BLH_GPIO_BANK and BLH_GPIO_PIN when detecting hold using GPIO
#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)
#ifdef IMX233_BUTTON_LRADC_VDDIO
#define HAS_VDDIO
#endif
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 raw_val;
#ifdef HAS_VDDIO
static int vddio_chan;
static int vddio_val;
#endif
static int delay_chan_mask; // trigger channel mask
static int irq_chan_mask; // triggered channel mask
static int button_find(int val)
{
#ifdef IMX233_BUTTON_LRADC_VDDIO
val = (val * IMX233_BUTTON_LRADC_VDDIO) / vddio_val;
#endif
// 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;
}
static void button_lradc_irq(int chan)
{
/* read value, clear channel */
#ifdef HAS_VDDIO
if(chan == vddio_chan)
{
vddio_val = imx233_lradc_read_channel(vddio_chan) / SAMPLES;
vddio_val *= 2; /* VDDIO channel has internal divider */
imx233_lradc_clear_channel(vddio_chan);
imx233_lradc_setup_channel(vddio_chan, true, true, SAMPLES - 1, LRADC_SRC_VDDIO);
}
#endif
if(chan == button_chan)
{
raw_val = 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));
}
/* record irq, trigger delay if all IRQs have been fired */
irq_chan_mask |= 1 << chan;
if(irq_chan_mask == delay_chan_mask)
{
irq_chan_mask = 0;
imx233_lradc_setup_delay(button_delay, delay_chan_mask, 0, SAMPLES - 1, DELAY);
imx233_lradc_kick_delay(button_delay);
/* compute mask, compare to previous one */
button_val[button_idx] = button_find(raw_val);
button_idx = 1 - button_idx;
if(button_val[0] == button_val[1])
button_mask = button_val[0];
}
}
void imx233_button_lradc_init(void)
{
table_size = 0;
while(imx233_button_lradc_mapping[table_size].btn != IMX233_BUTTON_LRADC_END)
table_size++;
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_enable_channel_irq(button_chan, true);
imx233_lradc_set_channel_irq_callback(button_chan, button_lradc_irq);
delay_chan_mask = 1 << button_chan;
#ifdef HAS_VDDIO
vddio_chan = imx233_lradc_acquire_channel(LRADC_SRC_VDDIO, TIMEOUT_NOBLOCK);
if(vddio_chan < 0)
panicf("Cannot get vddio channel for button-lradc");
imx233_lradc_setup_channel(vddio_chan, true, true, SAMPLES - 1, LRADC_SRC_VDDIO);
imx233_lradc_enable_channel_irq(vddio_chan, true);
imx233_lradc_set_channel_irq_callback(vddio_chan, button_lradc_irq);
delay_chan_mask |= 1 << vddio_chan;
#endif
imx233_lradc_setup_delay(button_delay, delay_chan_mask, 0, SAMPLES - 1, DELAY);
imx233_lradc_kick_delay(button_delay);
#if defined(HAS_BUTTON_HOLD) && IMX233_BUTTON_LRADC_HOLD_DET == BLH_GPIO
imx233_pinctrl_acquire(BLH_GPIO_BANK, BLH_GPIO_PIN, "button_lradc_hold");
imx233_pinctrl_set_function(BLH_GPIO_BANK, BLH_GPIO_PIN, PINCTRL_FUNCTION_GPIO);
imx233_pinctrl_enable_gpio(BLH_GPIO_BANK, BLH_GPIO_PIN, false);
# ifdef BLH_GPIO_PULLUP
imx233_pinctrl_enable_pullup(BLH_GPIO_BANK, BLH_GPIO_PIN, true);
# endif
#endif
}
#if defined(HAS_BUTTON_HOLD) && IMX233_BUTTON_LRADC_HOLD_DET == BLH_ADC
bool imx233_button_lradc_hold(void)
{
return button_mask == IMX233_BUTTON_LRADC_HOLD;
}
#endif
#if defined(HAS_BUTTON_HOLD) && IMX233_BUTTON_LRADC_HOLD_DET == BLH_GPIO
bool imx233_button_lradc_hold(void)
{
bool res = imx233_pinctrl_get_gpio(BLH_GPIO_BANK, BLH_GPIO_PIN);
#ifdef BLH_GPIO_INVERTED
res = !res;
#endif
return res;
}
#endif
int imx233_button_lradc_read(int others)
{
#ifdef HAS_BUTTON_HOLD
return imx233_button_lradc_hold() ? 0 : button_mask | others;
#else
return button_mask | others;
#endif
}
int imx233_button_lradc_read_raw(void)
{
return raw_val;
}
#ifdef HAS_VDDIO
int imx233_button_lradc_read_vddio(void)
{
return vddio_val; // the VDDIO channel has an internal divider
}
#endif