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imx233: make button-lradc drive able to handle VDDIO derived values

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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
This commit is contained in:
Amaury Pouly 2014-02-04 00:23:35 +01:00
parent 0e0c610df0
commit 0324bf59a8
4 changed files with 93 additions and 13 deletions
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73
firmware/target/arm/imx233/button-lradc-imx233.c
View file

@ -58,6 +58,10 @@
/* 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];
@ -65,9 +69,18 @@ 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 */
@ -91,18 +104,35 @@ static int button_find(int val)
static void button_lradc_irq(int chan)
{
(void) chan;
/* read value, kick channel */
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));
imx233_lradc_setup_delay(button_delay, 1 << button_chan, 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];
/* 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)
@ -118,9 +148,19 @@ void imx233_button_lradc_init(void)
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);
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");
@ -164,3 +204,10 @@ 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

19
firmware/target/arm/imx233/button-lradc-imx233.h
View file

@ -30,7 +30,19 @@
* - imx233_button_lradc_mapping: target-defined table of adc values and mapping
* - IMX233_BUTTON_LRADC_CHANNEL: lradc channel to use
* - IMX233_BUTTON_LRADC_HOLD_DET: define hold detection method (ignored if !HAS_BUTTON_HOLD)
* - IMX233_BUTTON_LRADC_MODE: define the button lradc mode
*
* The LRADC code supports two modes of operations: VDDIO relative or absolute.
* In the (default) absolute value mode, the LRADC channel is sampled and its value
* is compared to the one in the imx233_button_lradc_mapping table. This is
* appropriate when the resistor ladder is derived from a fixed voltage.
* In the VDDIO relative mode, the values in imx233_button_lradc_mapping are
* the values for a specific value of VDDIO which is given by
* IMX233_BUTTON_LRADC_VDDIO. In this mode, the code will also sample VDDIO
* and do the following comparison:
* lradc_value <=? imx233_button_lradc_mapping[i] * vddio_ref / vddio_value
* where vddio_ref is IMX233_BUTTON_LRADC_VDDIO.
*
* The available values of IMX233_BUTTON_LRADC_HOLD are:
* - BLH_ADC: detect hold using adc
* - BLH_EXT: target button driver implements imx233_button_lradc_hold() using
@ -40,6 +52,10 @@
* + BLH_GPIO_PIN: pin in bank
* + BLH_GPIO_INVERTED: define if inverted, default is active high
* + BLH_GPIO_PULLUP: define if pins needs pullup
*
* WARNING
* There must always be entry in imx233_button_lradc_mapping whose value is the steady
* value of the channel when no button is pressed, and which maps to no button (.btn = 0)
*/
/* hold detect method */
@ -74,5 +90,8 @@ int imx233_button_lradc_read(int others);
bool imx233_button_lradc_hold(void);
#endif
int imx233_button_lradc_read_raw(void); // return raw adc value
#ifdef IMX233_BUTTON_LRADC_VDDIO
int imx233_button_lradc_read_vddio(void);
#endif
#endif /* __button_lradc_imx233__ */

11
firmware/target/arm/imx233/creative-zen/button-target.h
View file

@ -25,11 +25,22 @@
bool button_debug_screen(void);
/* HOLD button */
#if !defined(CREATIVE_ZENXFISTYLE)
#define HAS_BUTTON_HOLD
#define IMX233_BUTTON_LRADC_HOLD_DET BLH_ADC
#endif
/* VDDIO value */
#if defined(CREATIVE_ZENXFISTYLE)
#define IMX233_BUTTON_LRADC_VDDIO 3660
#elif defined(CREATIVE_ZEN)
#define IMX233_BUTTON_LRADC_VDDIO 3480
#elif defined(CREATIVE_ZENXFI)
#define IMX233_BUTTON_LRADC_VDDIO 3500
#endif
/* LRADC channel */
#if defined(CREATIVE_ZENXFISTYLE)
#define IMX233_BUTTON_LRADC_CHANNEL 2
#else

3
firmware/target/arm/imx233/lradc-imx233.h
View file

@ -65,6 +65,9 @@
/* frequency of the delay counter */
#define LRADC_DELAY_FREQ 2000
/* maximum value of a sample (without accumulation), defines the precision */
#define LRADC_MAX_VALUE 4096
typedef void (*lradc_irq_fn_t)(int chan);
void imx233_lradc_init(void);