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>

1 files changed, 73 insertions, 0 deletions

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 */