ec_chip_mchp: Clear ADC sticky hardware status before starting.

Before starting an ADC conversion clear sticky hardware status
in ADC and interrupt aggregator.

BRANCH=none
BUG=
TEST=Build boards using chip mchp and check for spurious
ADC interrupts.
CQ-DEPEND=CL:1053576

Change-Id: I48b07ecaac2976c5e06e23a4ecf4397ed41c89d1
Signed-off-by: scott worley <scott.worley@microchip.corp-partner.google.com>
Reviewed-on: https://chromium-review.googlesource.com/1053867
Commit-Ready: Randall Spangler <rspangler@chromium.org>
Tested-by: Scott Worley <scott.worley@microchip.corp-partner.google.com>
Reviewed-by: Randall Spangler <rspangler@chromium.org>

1 files changed, 36 insertions, 19 deletions

diff --git a/chip/mchp/adc.c b/chip/mchp/adc.c
index 4fe1a384c0..6278bc1ebd 100644
--- a/chip/mchp/adc.c
+++ b/chip/mchp/adc.c
@@ -7,6 +7,7 @@
 #include "adc_chip.h"
 #include "common.h"
 #include "console.h"
+#include "gpio.h"
 #include "hooks.h"
 #include "registers.h"
 #include "task.h"
@@ -30,16 +31,37 @@ struct mutex adc_lock;
  */
 static task_id_t task_waiting;
 
+/*
+ * Start ADC single-shot conversion.
+ * 1. Disable ADC interrupt.
+ * 2. Clear sticky hardware status.
+ * 3. Start conversion.
+ * 4. Enable interrupt.
+ * 5. Wait with timeout for ADC ISR to
+ *    to set TASK_EVENT_TIMER.
+ */
 static int start_single_and_wait(int timeout)
 {
 	int event;
 
+	MCHP_INT_DISABLE(MCHP_ADC_GIRQ) = MCHP_ADC_GIRQ_SINGLE_BIT;
 	task_waiting = task_get_current();
 
+	/* clear all R/W1C channel status */
+	MCHP_ADC_STS = 0xffffu;
+	/* clear R/W1C single done status */
+	MCHP_ADC_CTRL |= (1 << 7);
+	/* clear GIRQ single status */
+	MCHP_INT_SOURCE(MCHP_ADC_GIRQ) = MCHP_ADC_GIRQ_SINGLE_BIT;
+	/* make sure all writes are issued before starting conversion */
+	asm volatile ("dsb");
+
 	/* Start conversion */
 	MCHP_ADC_CTRL |= 1 << 1;
 
-	/* Wait for interrupt */
+	MCHP_INT_ENABLE(MCHP_ADC_GIRQ) = MCHP_ADC_GIRQ_SINGLE_BIT;
+
+	/* Wait for interrupt, ISR disables interrupt */
 	event = task_wait_event(timeout);
 	task_waiting = TASK_ID_INVALID;
 	return event != TASK_EVENT_TIMER;
@@ -50,25 +72,16 @@ int adc_read_channel(enum adc_channel ch)
 	const struct adc_t *adc = adc_channels + ch;
 	int value;
 
-	trace1(0, ADC, 0, "adc_read_channel %d", ch);
-
 	mutex_lock(&adc_lock);
 
-	trace1(0, ADC, 0,
-	       "adc_read_channel acquired mutex. Physical channel = %d",
-	       adc->channel);
-
 	MCHP_ADC_SINGLE = 1 << adc->channel;
 
 	if (start_single_and_wait(ADC_SINGLE_READ_TIME))
-		value = MCHP_ADC_READ(adc->channel) * adc->factor_mul /
+		value = (MCHP_ADC_READ(adc->channel) * adc->factor_mul) /
 			adc->factor_div + adc->shift;
 	else
 		value = ADC_READ_ERROR;
 
-	trace11(0, ADC, 0,
-		"adc_read_channel value = 0x%08X. Releasing mutex", value);
-
 	mutex_unlock(&adc_lock);
 	return value;
 }
@@ -79,12 +92,8 @@ int adc_read_all_channels(int *data)
 	int ret = EC_SUCCESS;
 	const struct adc_t *adc;
 
-	trace0(0, ADC, 0, "adc_read_all_channels");
-
 	mutex_lock(&adc_lock);
 
-	trace0(0, ADC, 0, "adc_read_all_channels acquired mutex");
-
 	MCHP_ADC_SINGLE = 0;
 	for (i = 0; i < ADC_CH_COUNT; ++i)
 		MCHP_ADC_SINGLE |= 1 << adc_channels[i].channel;
@@ -96,25 +105,28 @@ int adc_read_all_channels(int *data)
 
 	for (i = 0; i < ADC_CH_COUNT; ++i) {
 		adc = adc_channels + i;
-		data[i] = MCHP_ADC_READ(adc->channel) * adc->factor_mul /
+		data[i] = (MCHP_ADC_READ(adc->channel) * adc->factor_mul) /
 			  adc->factor_div + adc->shift;
-		trace12(0, ADC, 0, "adc all: data[%d] = 0x%08X", i, data[i]);
 	}
 
 exit_all_channels:
 	mutex_unlock(&adc_lock);
-	trace0(0, ADC, 0, "adc_read_all_channels released mutex");
 
 	return ret;
 }
 
 /*
- * Using MEC1701 direct mode interrupts. Do not
+ * Enable GPIO pins.
+ * Using MEC17xx direct mode interrupts. Do not
  * set Interrupt Aggregator Block Enable bit
  * for GIRQ containing ADC.
  */
 static void adc_init(void)
 {
+	trace0(0, ADC, 0, "adc_init");
+
+	gpio_config_module(MODULE_ADC, 1);
+
 	/* clear ADC sleep enable */
 	MCHP_PCR_SLP_DIS_DEV(MCHP_PCR_ADC);
 
@@ -130,6 +142,11 @@ DECLARE_HOOK(HOOK_INIT, adc_init, HOOK_PRIO_INIT_ADC);
 
 void adc_interrupt(void)
 {
+	MCHP_INT_DISABLE(MCHP_ADC_GIRQ) = MCHP_ADC_GIRQ_SINGLE_BIT;
+
+	/* clear individual chan conversion status */
+	MCHP_ADC_STS = 0xffffu;
+
 	/* Clear interrupt status bit */
 	MCHP_ADC_CTRL |= 1 << 7;