it83xx/adc: add voltage comparator feature

  Add voltage comparator feature.

BUG=b:149094481
BRANCH=none
TEST=on board it83xx_evb,
     1.set VCMP1 threshold 2.8v: external input 3v,
       the INT would be triggered and ADC5 read the correctly voltage.

     2.set VCMP0 threshold 0.2v: external input 0v,
       the INT would be triggered and ADC5 read the correctly voltage.

Change-Id: I59510b1c6bd38004ff06e0fcbd2a671e895d59e3
Signed-off-by: Ruibin Chang <ruibin.chang@ite.com.tw>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2062110
Tested-by: Ruibin Chang <Ruibin.Chang@ite.com.tw>
Reviewed-by: Diana Z <dzigterman@chromium.org>
Commit-Queue: Ruibin Chang <Ruibin.Chang@ite.com.tw>

6 files changed, 244 insertions, 0 deletions

diff --git a/chip/it83xx/adc.c b/chip/it83xx/adc.c
index b6d5a7dbc1..0af56e32a3 100644
--- a/chip/it83xx/adc.c
+++ b/chip/it83xx/adc.c
@@ -62,6 +62,31 @@ const struct adc_ctrl_t adc_ctrl_regs[] = {
 };
 BUILD_ASSERT(ARRAY_SIZE(adc_ctrl_regs) == CHIP_ADC_COUNT);
 
+#ifdef CONFIG_ADC_VOLTAGE_COMPARATOR
+#define VCMP_ADC_CH_MASK_H           BIT(3)
+#define VCMP_ADC_CH_MASK_L           0x7
+/* 10-bits resolution */
+#define VCMP_RESOLUTION              BIT(10)
+#define VCMP_MAX_MVOLT               3000
+
+/* Data structure of voltage comparator control registers. */
+const struct vcmp_ctrl_t vcmp_ctrl_regs[] = {
+	{&IT83XX_ADC_VCMP0CTL, &IT83XX_ADC_VCMP0CSELM, &IT83XX_ADC_CMP0THRDATM,
+		&IT83XX_ADC_CMP0THRDATL},
+	{&IT83XX_ADC_VCMP1CTL, &IT83XX_ADC_VCMP1CSELM, &IT83XX_ADC_CMP1THRDATM,
+		&IT83XX_ADC_CMP1THRDATL},
+	{&IT83XX_ADC_VCMP2CTL, &IT83XX_ADC_VCMP2CSELM, &IT83XX_ADC_CMP2THRDATM,
+		&IT83XX_ADC_CMP2THRDATL},
+	{&IT83XX_ADC_VCMP3CTL, &IT83XX_ADC_VCMP3CSELM, &IT83XX_ADC_CMP3THRDATM,
+		&IT83XX_ADC_CMP3THRDATL},
+	{&IT83XX_ADC_VCMP4CTL, &IT83XX_ADC_VCMP4CSELM, &IT83XX_ADC_CMP4THRDATM,
+		&IT83XX_ADC_CMP4THRDATL},
+	{&IT83XX_ADC_VCMP5CTL, &IT83XX_ADC_VCMP5CSELM, &IT83XX_ADC_CMP5THRDATM,
+		&IT83XX_ADC_CMP5THRDATL},
+};
+BUILD_ASSERT(ARRAY_SIZE(vcmp_ctrl_regs) == CHIP_VCMP_COUNT);
+#endif
+
 static void adc_enable_channel(int ch)
 {
 	if (ch < CHIP_ADC_CH4)
@@ -190,6 +215,110 @@ void adc_interrupt(void)
 		task_set_event(task_waiting, TASK_EVENT_ADC_DONE, 0);
 }
 
+#ifdef CONFIG_ADC_VOLTAGE_COMPARATOR
+/* Clear voltage comparator interrupt status */
+void clear_vcmp_status(int vcmp_x)
+{
+	if (vcmp_x <= CHIP_VCMP2)
+		IT83XX_ADC_VCMPSTS = BIT(vcmp_x);
+	else
+		IT83XX_ADC_VCMPSTS2 = BIT(vcmp_x - CHIP_VCMP3);
+}
+
+/* Enable/Disable voltage comparator interrupt */
+void vcmp_enable(int idx, int enable)
+{
+	if (enable) {
+		/* Enable comparator interrupt */
+		*vcmp_ctrl_regs[idx].vcmp_ctrl |= ADC_VCMP_CMPINTEN;
+		/* Start voltage comparator */
+		*vcmp_ctrl_regs[idx].vcmp_ctrl |= ADC_VCMP_CMPEN;
+	} else {
+		/* Stop voltage comparator */
+		*vcmp_ctrl_regs[idx].vcmp_ctrl &= ~ADC_VCMP_CMPEN;
+		/* Disable comparator interrupt */
+		*vcmp_ctrl_regs[idx].vcmp_ctrl &= ~ADC_VCMP_CMPINTEN;
+	}
+}
+
+/* Set voltage comparator conditions */
+void set_voltage_comparator_condition(int idx)
+{
+	int val;
+
+	/* CMPXTHRDAT[9:0] = threshold(mv) * 1024 / 3000(mv) */
+	val = vcmp_list[idx].threshold * VCMP_RESOLUTION / VCMP_MAX_MVOLT;
+	*vcmp_ctrl_regs[idx].vcmp_datl = (uint8_t)(val & 0xff);
+	*vcmp_ctrl_regs[idx].vcmp_datm = (uint8_t)((val >> 8) & 0xff);
+
+	/* Select greater or less equal than threshold */
+	if (vcmp_list[idx].flag & GREATER_THRESHOLD)
+		*vcmp_ctrl_regs[idx].vcmp_ctrl |= ADC_VCMP_GREATER_THRESHOLD;
+	else
+		*vcmp_ctrl_regs[idx].vcmp_ctrl &= ~ADC_VCMP_GREATER_THRESHOLD;
+}
+
+/* Voltage comparator interrupt, handle one channel at a time. */
+void voltage_comparator_interrupt(void)
+{
+	int idx, status;
+
+	/* Find out which voltage comparator triggered */
+	status = IT83XX_ADC_VCMPSTS & 0x07;
+	status |= (IT83XX_ADC_VCMPSTS2 & 0x07) << 3;
+
+	for (idx = CHIP_VCMP0; idx < VCMP_COUNT; idx++) {
+		if (status & BIT(idx)) {
+			/* Called back to board-level function */
+			if (vcmp_list[idx].vcmp_thresh_cb)
+				vcmp_list[idx].vcmp_thresh_cb();
+			/* Clear voltage comparator interrupt status */
+			clear_vcmp_status(idx);
+		}
+	}
+
+	/* Clear interrupt status */
+	task_clear_pending_irq(IT83XX_IRQ_V_COMP);
+}
+
+/* Voltage comparator initialization */
+static void voltage_comparator_init(void)
+{
+	int idx;
+
+	/* No voltage comparator is declared */
+	if (!VCMP_COUNT)
+		return;
+
+	for (idx = CHIP_VCMP0; idx < VCMP_COUNT; idx++) {
+		/*
+		 * Select voltage comparator:
+		 * vcmp_list[i] use voltage comparator i, i = 0 ~ 5.
+		 */
+
+		/* Select which ADC channel output voltage into comparator */
+		*vcmp_ctrl_regs[idx].vcmp_ctrl |=
+			vcmp_list[idx].adc_ch & VCMP_ADC_CH_MASK_L;
+		if (vcmp_list[idx].adc_ch & VCMP_ADC_CH_MASK_H)
+			*vcmp_ctrl_regs[idx].vcmp_adc_chm |= ADC_VCMP_VCMPCSELM;
+
+		/* Set "all voltage comparator" scan period */
+		IT83XX_ADC_VCMPSCP = vcmp_list[idx].scan_period;
+		/* Set voltage comparator conditions */
+		set_voltage_comparator_condition(idx);
+		/* Clear voltage comparator interrupt status */
+		clear_vcmp_status(idx);
+		/* Enable comparator interrupt and start */
+		vcmp_enable(idx, 1);
+	}
+
+	/* Clear interrupt status */
+	task_clear_pending_irq(IT83XX_IRQ_V_COMP);
+	/* Enable voltage comparator to interrupt MCU */
+	task_enable_irq(IT83XX_IRQ_V_COMP);
+}
+#endif
+
 /*
  * ADC analog accuracy initialization (only once after VSTBY power on)
  *
@@ -241,6 +370,15 @@ static void adc_init(void)
 	/* disable adc interrupt */
 	task_disable_irq(IT83XX_IRQ_ADC);
 
+#ifdef CONFIG_ADC_VOLTAGE_COMPARATOR
+	/*
+	 * Init voltage comparator
+	 * NOTE:ADC channel signal output to voltage comparator,
+	 *      so we need set the channel to ADC alternate mode first.
+	 */
+	voltage_comparator_init();
+#endif
+
 	adc_init_done = 1;
 }
 DECLARE_HOOK(HOOK_INIT, adc_init, HOOK_PRIO_INIT_ADC);
diff --git a/chip/it83xx/adc_chip.h b/chip/it83xx/adc_chip.h
index c43a64c132..e894e97b64 100644
--- a/chip/it83xx/adc_chip.h
+++ b/chip/it83xx/adc_chip.h
@@ -41,6 +41,33 @@ enum chip_adc_channel {
 	CHIP_ADC_COUNT,
 };
 
+/* List of voltage comparator. */
+enum chip_vcmp {
+	CHIP_VCMP0 = 0,
+	CHIP_VCMP1,
+	CHIP_VCMP2,
+	CHIP_VCMP3,
+	CHIP_VCMP4,
+	CHIP_VCMP5,
+	CHIP_VCMP_COUNT,
+};
+
+/* List of voltage comparator scan period times. */
+enum vcmp_scan_period {
+	VCMP_SCAN_PERIOD_100US = 0x10,
+	VCMP_SCAN_PERIOD_200US = 0x20,
+	VCMP_SCAN_PERIOD_400US = 0x30,
+	VCMP_SCAN_PERIOD_600US = 0x40,
+	VCMP_SCAN_PERIOD_800US = 0x50,
+	VCMP_SCAN_PERIOD_1MS   = 0x60,
+	VCMP_SCAN_PERIOD_1_5MS = 0x70,
+	VCMP_SCAN_PERIOD_2MS   = 0x80,
+	VCMP_SCAN_PERIOD_2_5MS = 0x90,
+	VCMP_SCAN_PERIOD_3MS   = 0xA0,
+	VCMP_SCAN_PERIOD_4MS   = 0xB0,
+	VCMP_SCAN_PERIOD_5MS   = 0xC0,
+};
+
 /* Data structure to define ADC channel control registers. */
 struct adc_ctrl_t {
 	volatile uint8_t *adc_ctrl;
@@ -58,10 +85,56 @@ struct adc_t {
 	enum chip_adc_channel channel;
 };
 
+/* Data structure to define voltage comparator control registers. */
+struct vcmp_ctrl_t {
+	volatile uint8_t *vcmp_ctrl;
+	volatile uint8_t *vcmp_adc_chm;
+	volatile uint8_t *vcmp_datm;
+	volatile uint8_t *vcmp_datl;
+};
+
+/* supported flags (member "flag" in struct vcmp_t) for voltage comparator */
+#define GREATER_THRESHOLD         BIT(0)
+#define LESS_EQUAL_THRESHOLD      BIT(1)
+
+/* Data structure for board to define voltage comparator list. */
+struct vcmp_t {
+	const char *name;
+	int threshold;
+	/*
+	 * Select greater/less equal threshold.
+	 * NOTE: once edge trigger interrupt fires, we need disable the voltage
+	 *       comparator, or the matching threshold level will infinitely
+	 *       triggers interrupt.
+	 */
+	char flag;
+	/* Called when the interrupt fires */
+	void (*vcmp_thresh_cb)(void);
+	/*
+	 * Select "all voltage comparator" scan period time.
+	 * The power consumption is positively relative with scan frequency.
+	 */
+	enum vcmp_scan_period scan_period;
+	/*
+	 * Select which ADC channel output voltage into comparator and we
+	 * should set the ADC channel pin in alternate mode via adc_channels[].
+	 */
+	enum chip_adc_channel adc_ch;
+};
+
 /*
  * Boards must provide this list of ADC channel definitions. This must match
  * the enum adc_channel list provided by the board.
  */
 extern const struct adc_t adc_channels[];
 
+#ifdef CONFIG_ADC_VOLTAGE_COMPARATOR
+/*
+ * Boards must provide this list of voltage comparator definitions.
+ * This must match the enum board_vcmp list provided by the board.
+ */
+extern const struct vcmp_t vcmp_list[];
+void vcmp_enable(int index, int enable);
+#endif
+
 #endif /* __CROS_EC_ADC_CHIP_H */
diff --git a/chip/it83xx/intc.c b/chip/it83xx/intc.c
index 1a6e6c74dc..8c1c092ed5 100644
--- a/chip/it83xx/intc.c
+++ b/chip/it83xx/intc.c
@@ -178,6 +178,11 @@ void intc_cpu_int_group_7(void)
 	case IT83XX_IRQ_ADC:
 		adc_interrupt();
 		break;
+#ifdef CONFIG_ADC_VOLTAGE_COMPARATOR
+	case IT83XX_IRQ_V_COMP:
+		voltage_comparator_interrupt();
+		break;
+#endif
 #endif
 	default:
 		break;
diff --git a/chip/it83xx/intc.h b/chip/it83xx/intc.h
index 5a31c41b9c..45447db485 100644
--- a/chip/it83xx/intc.h
+++ b/chip/it83xx/intc.h
@@ -27,6 +27,9 @@ void pm5_ibf_interrupt(void);
 void lpcrst_interrupt(enum gpio_signal signal);
 void peci_interrupt(void);
 void adc_interrupt(void);
+#ifdef CONFIG_ADC_VOLTAGE_COMPARATOR
+void voltage_comparator_interrupt(void);
+#endif
 void i2c_interrupt(int port);
 #ifdef CONFIG_I2C_SLAVE
 void i2c_slv_interrupt(int port);
diff --git a/chip/it83xx/registers.h b/chip/it83xx/registers.h
index 3eceda91de..ff2467c606 100644
--- a/chip/it83xx/registers.h
+++ b/chip/it83xx/registers.h
@@ -1065,6 +1065,11 @@ enum clock_gate_offsets {
 #define IT83XX_ADC_ADCDVSTS     REG8(IT83XX_ADC_BASE+0x44)
 #define IT83XX_ADC_VCMPSTS      REG8(IT83XX_ADC_BASE+0x45)
 #define IT83XX_ADC_VCMP0CTL     REG8(IT83XX_ADC_BASE+0x46)
+#define ADC_VCMP_CMPEN              BIT(7)
+#define ADC_VCMP_CMPINTEN           BIT(6)
+#define ADC_VCMP_GREATER_THRESHOLD  BIT(5)
+#define ADC_VCMP_EDGE_TRIGGER       BIT(4)
+#define ADC_VCMP_GPIO_ACTIVE_LOW    BIT(3)
 #define IT83XX_ADC_CMP0THRDATM  REG8(IT83XX_ADC_BASE+0x47)
 #define IT83XX_ADC_CMP0THRDATL  REG8(IT83XX_ADC_BASE+0x48)
 #define IT83XX_ADC_VCMP1CTL     REG8(IT83XX_ADC_BASE+0x49)
@@ -1086,6 +1091,23 @@ enum clock_gate_offsets {
 #define IT83XX_ADC_VCH16DATM    REG8(IT83XX_ADC_BASE+0x6A)
 #define IT83XX_ADC_VCH16DATL    REG8(IT83XX_ADC_BASE+0x6B)
 #define IT83XX_ADC_ADCDVSTS2    REG8(IT83XX_ADC_BASE+0x6C)
+#define IT83XX_ADC_VCMPSTS2     REG8(IT83XX_ADC_BASE+0x6D)
+#define IT83XX_ADC_VCMP3CTL     REG8(IT83XX_ADC_BASE+0x6E)
+#define IT83XX_ADC_CMP3THRDATM  REG8(IT83XX_ADC_BASE+0x6F)
+#define IT83XX_ADC_CMP3THRDATL  REG8(IT83XX_ADC_BASE+0x70)
+#define IT83XX_ADC_VCMP4CTL     REG8(IT83XX_ADC_BASE+0x71)
+#define IT83XX_ADC_CMP4THRDATM  REG8(IT83XX_ADC_BASE+0x72)
+#define IT83XX_ADC_CMP4THRDATL  REG8(IT83XX_ADC_BASE+0x73)
+#define IT83XX_ADC_VCMP5CTL     REG8(IT83XX_ADC_BASE+0x74)
+#define IT83XX_ADC_CMP5THRDATM  REG8(IT83XX_ADC_BASE+0x75)
+#define IT83XX_ADC_CMP5THRDATL  REG8(IT83XX_ADC_BASE+0x76)
+#define IT83XX_ADC_VCMP0CSELM   REG8(IT83XX_ADC_BASE+0x77)
+#define ADC_VCMP_VCMPCSELM          BIT(0)
+#define IT83XX_ADC_VCMP1CSELM   REG8(IT83XX_ADC_BASE+0x78)
+#define IT83XX_ADC_VCMP2CSELM   REG8(IT83XX_ADC_BASE+0x79)
+#define IT83XX_ADC_VCMP3CSELM   REG8(IT83XX_ADC_BASE+0x7A)
+#define IT83XX_ADC_VCMP4CSELM   REG8(IT83XX_ADC_BASE+0x7B)
+#define IT83XX_ADC_VCMP5CSELM   REG8(IT83XX_ADC_BASE+0x7C)
 
 /* Digital to Analog Converter (DAC) */
 #define IT83XX_DAC_BASE   0x00F01A00
diff --git a/include/config.h b/include/config.h
index 969e6aa674..ba48d21b71 100644
--- a/include/config.h
+++ b/include/config.h
@@ -248,6 +248,9 @@
  */
 #undef CONFIG_ADC_SAMPLE_TIME
 
+/* Support voltage comparator */
+#undef CONFIG_ADC_VOLTAGE_COMPARATOR
+
 /* Include the ADC analog watchdog feature in the ADC code */
 #define CONFIG_ADC_WATCHDOG