Implement EC lid switch handler

Implement EC lid switch interrupt handler and debouncing.

BUG=chrome-os-partner:7363
TEST=Manually test lid switch output signal is correct.
Use UART console to see debouncing is correct.

Change-Id: I74aad63330716da017fc4a57002349461c6a9b26

1 files changed, 102 insertions, 0 deletions

diff --git a/chip/lm4/gpio.c b/chip/lm4/gpio.c
index a00d771c53..7f613d1c80 100644
--- a/chip/lm4/gpio.c
+++ b/chip/lm4/gpio.c
@@ -7,7 +7,38 @@
 
 #include "gpio.h"
 #include "registers.h"
+#include "task.h"
+#include "timer.h"
 
+enum debounce_isr_id
+{
+	DEBOUNCE_LID,
+	DEBOUNCE_ISR_ID_MAX
+};
+
+struct debounce_isr_t
+{
+	/* TODO: Add a carry bit to indicate timestamp overflow */
+	timestamp_t tstamp;
+	int started;
+	void (*callback)(void);
+};
+
+struct debounce_isr_t debounce_isr[DEBOUNCE_ISR_ID_MAX];
+
+static void lid_switch_isr(void)
+{
+	/* TODO: Currently we pass through the LID_SW# pin to R_EC_LID_OUT#
+	         directly. Modify this if we need to consider more conditions.
+		 */
+	uint32_t val = LM4_GPIO_DATA(LM4_GPIO_K, 0x20);
+	if (val) {
+		LM4_GPIO_DATA(LM4_GPIO_F, 0x1) = 0x1;
+	}
+	else {
+		LM4_GPIO_DATA(LM4_GPIO_F, 0x1) = 0x0;
+	}
+}
 
 int gpio_pre_init(void)
 {
@@ -24,12 +55,36 @@ int gpio_pre_init(void)
 	LM4_GPIO_DEN(LM4_GPIO_A) |= 0x80;
 	LM4_GPIO_DIR(LM4_GPIO_A) |= 0x80;
 
+	/* Set up LID switch input (block K pin 5) */
+	LM4_GPIO_PCTL(LM4_GPIO_K) &= ~(0xf00000);
+	LM4_GPIO_DIR(LM4_GPIO_K) &= ~(0x20);
+	LM4_GPIO_PUR(LM4_GPIO_K) |= 0x20;
+	LM4_GPIO_DEN(LM4_GPIO_K) |= 0x20;
+	LM4_GPIO_IM(LM4_GPIO_K) |= 0x20;
+	LM4_GPIO_IBE(LM4_GPIO_K) |= 0x20;
+
+	/* Block F pin 0 is NMI pin, so we have to unlock GPIO Lock register and
+	   set the bit in GPIOCR register first. */
+	LM4_GPIO_LOCK(LM4_GPIO_F) = 0x4c4f434b;
+	LM4_GPIO_CR(LM4_GPIO_F) |= 0x1;
+	LM4_GPIO_LOCK(LM4_GPIO_F) = 0x0;
+
+	/* Set up LID switch output (block F pin 0) */
+	LM4_GPIO_PCTL(LM4_GPIO_F) &= ~(0xf);
+	LM4_GPIO_DATA(LM4_GPIO_F, 0x1) =
+		(LM4_GPIO_DATA(LM4_GPIO_K, 0x20) ? 1 : 0);
+	LM4_GPIO_DIR(LM4_GPIO_F) |= 0x1;
+	LM4_GPIO_DEN(LM4_GPIO_F) |= 0x1;
+
 	return EC_SUCCESS;
 }
 
 
 int gpio_init(void)
 {
+	debounce_isr[DEBOUNCE_LID].started = 0;
+	debounce_isr[DEBOUNCE_LID].callback = lid_switch_isr;
+
 	return EC_SUCCESS;
 }
 
@@ -56,3 +111,50 @@ int gpio_set(enum gpio_signal signal, int value)
 		return EC_ERROR_UNKNOWN;
 	}
 }
+
+static void gpio_interrupt(int port, uint32_t mis)
+{
+	timestamp_t timelimit;
+
+	/* Set 30 ms debounce timelimit */
+	timelimit = get_time();
+	timelimit.val += 30000;
+
+	/* Handle interrupts */
+	if (port == LM4_GPIO_K && (mis & 0x20)) {
+		debounce_isr[DEBOUNCE_LID].tstamp = timelimit;
+		debounce_isr[DEBOUNCE_LID].started = 1;
+	}
+}
+
+static void __gpio_k_interrupt(void)
+{
+	uint32_t mis = LM4_GPIO_MIS(LM4_GPIO_K);
+
+	/* Clear the interrupt bits we received */
+	LM4_GPIO_ICR(LM4_GPIO_K) = mis;
+
+	gpio_interrupt(LM4_GPIO_K, mis);
+}
+
+DECLARE_IRQ(LM4_IRQ_GPIOK, __gpio_k_interrupt, 1);
+
+int gpio_task(void)
+{
+	int i;
+	timestamp_t ts;
+
+	while (1) {
+		usleep(1000);
+		ts = get_time();
+		for (i = 0; i < DEBOUNCE_ISR_ID_MAX; ++i) {
+			if (debounce_isr[i].started &&
+				ts.val >= debounce_isr[i].tstamp.val) {
+				debounce_isr[i].started = 0;
+				debounce_isr[i].callback();
+			}
+		}
+	}
+
+	return EC_SUCCESS;
+}