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stm32f: Set ADC single read timeout

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If an ADC read fails and EOC bit is somehow never set, we will be stuck
in the read function holding mutex lock forever, which is really bad.
Let's set a timeout for this.

BUG=chrome-os-partner:18997
TEST=Boot Spring. Check ADC works.
BRANCH=spring

Change-Id: I19b108326f34f380497606fe92eabfaf0a778bb4
Signed-off-by: Vic Yang <victoryang@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/50338
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>
This commit is contained in:
Vic Yang
2013-05-08 02:43:59 +08:00
committed by ChromeBot
parent 0fe217c745
commit 235e6e1d0d
1 changed files with 13 additions and 4 deletions
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17
chip/stm32/adc.c
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@@ -14,6 +14,8 @@
#include "timer.h"
#include "util.h"
#define ADC_SINGLE_READ_TIMEOUT 3000 /* 3 ms */
struct mutex adc_lock;
static int watchdog_ain_id;
@@ -170,6 +172,7 @@ int adc_read_channel(enum adc_channel ch)
const struct adc_t *adc = adc_channels + ch;
int value;
int restore_watchdog = 0;
timestamp_t deadline;
if (!adc_powered())
return EC_ERROR_UNKNOWN;
@@ -190,15 +193,21 @@ int adc_read_channel(enum adc_channel ch)
STM32_ADC_CR2 |= (1 << 0); /* ADON */
/* Wait for EOC bit set */
while (!adc_conversion_ended())
;
value = STM32_ADC_DR & ADC_READ_MAX;
deadline.val = get_time().val + ADC_SINGLE_READ_TIMEOUT;
value = ADC_READ_ERROR;
do {
if (adc_conversion_ended()) {
value = STM32_ADC_DR & ADC_READ_MAX;
break;
}
} while (!timestamp_expired(deadline, NULL));
if (restore_watchdog)
adc_enable_watchdog_no_lock();
mutex_unlock(&adc_lock);
return value * adc->factor_mul / adc->factor_div + adc->shift;
return (value == ADC_READ_ERROR) ? ADC_READ_ERROR :
value * adc->factor_mul / adc->factor_div + adc->shift;
}
int adc_read_all_channels(int *data)