System76 common board directory (#53)

* Move configuration for battery into board.mk

* lemp9: remove tcpm code

* Move touchpad to its own module

* Add kbled_reset to all platforms, move items to run on CPU reset to a function

* Add defines for battery and charger address

* Add I2C_0 export to it5570e

* Move common system76 board functions into src/board/system76/common

src/board/system76/common/peci.c

@@ -0,0 +1,178 @@
+#include <stdbool.h>
+
+#include <board/peci.h>
+#include <board/power.h>
+#include <common/debug.h>
+#include <common/macro.h>
+#include <ec/gpio.h>
+#include <ec/pwm.h>
+
+// Fan speed is the lowest requested over HEATUP seconds
+#define HEATUP 10
+
+// Fan speed is the highest HEATUP speed over COOLDOWN seconds
+#define COOLDOWN 10
+
+// Interpolate duty cycle
+#define INTERPOLATE 0
+
+// Tjunction = 100C for i7-8565U (and probably the same for all WHL-U)
+#define T_JUNCTION 100
+
+int16_t peci_offset = 0;
+int16_t peci_temp = 0;
+uint8_t peci_duty = 0;
+
+#define PECI_TEMP(X) (((int16_t)(X)) << 6)
+#define PWM_DUTY(X) ((uint8_t)(((((uint16_t)(X)) * 255) + 99) / 100))
+
+struct FanPoint {
+    int16_t temp;
+    uint8_t duty;
+};
+
+#define FAN_POINT(T, D) { .temp = PECI_TEMP(T), .duty = PWM_DUTY(D) }
+
+// Fan curve with temperature in degrees C, duty cycle in percent
+struct FanPoint __code FAN_POINTS[] = {
+    FAN_POINT(65,  40),
+    FAN_POINT(70,  55),
+    FAN_POINT(75,  75),
+    FAN_POINT(80, 100)
+};
+
+// Get duty cycle based on temperature, adapted from
+// https://github.com/pop-os/system76-power/blob/master/src/fan.rs
+uint8_t fan_duty(int16_t temp) {
+    for (int i = 0; i < ARRAY_SIZE(FAN_POINTS); i++) {
+        const struct FanPoint * cur = &FAN_POINTS[i];
+
+        // If exactly the current temp, return the current duty
+        if (temp == cur->temp) {
+            return cur->duty;
+        } else if (temp < cur->temp) {
+            // If lower than first temp, return 0%
+            if (i == 0) {
+                return PWM_DUTY(0);
+            } else {
+                const struct FanPoint * prev = &FAN_POINTS[i - 1];
+
+#if INTERPOLATE
+                // If in between current temp and previous temp, interpolate
+                if (temp > prev->temp) {
+                    int16_t dtemp = (cur->temp - prev->temp);
+                    int16_t dduty = ((int16_t)cur->duty) - ((int16_t)prev->duty);
+                    return (uint8_t)(
+                        ((int16_t)prev->duty) +
+                        ((temp - prev->temp) * dduty) / dtemp
+                    );
+                }
+#else // INTERPOLATE
+                return prev->duty;
+#endif // INTERPOLATE
+            }
+        }
+    }
+
+    // If no point is found, return 100%
+    return PWM_DUTY(100);
+}
+
+uint8_t fan_heatup(uint8_t duty) {
+    static uint8_t history[HEATUP] = { 0 };
+    uint8_t lowest = duty;
+
+    int i;
+    for (i = 0; (i + 1) < ARRAY_SIZE(history); i++) {
+        uint8_t value = history[i + 1];
+        if (value < lowest) {
+            lowest = value;
+        }
+        history[i] = value;
+    }
+    history[i] = duty;
+
+    return lowest;
+}
+
+uint8_t fan_cooldown(uint8_t duty) {
+    static uint8_t history[COOLDOWN] = { 0 };
+    uint8_t highest = duty;
+
+    int i;
+    for (i = 0; (i + 1) < ARRAY_SIZE(history); i++) {
+        uint8_t value = history[i + 1];
+        if (value > highest) {
+            highest = value;
+        }
+        history[i] = value;
+    }
+    history[i] = duty;
+
+    return highest;
+}
+
+void peci_init(void) {
+    // Allow PECI pin to be used
+    GCR2 |= (1 << 4);
+
+    // Set frequency to 1MHz
+    HOCTL2R = 0x01;
+    // Set VTT to 1V
+    PADCTLR = 0x02;
+}
+
+// PECI information can be found here: https://www.intel.com/content/dam/www/public/us/en/documents/design-guides/core-i7-lga-2011-guide.pdf
+void peci_event(void) {
+    if (power_state == POWER_STATE_S0) {
+        // Use PECI if in S0 state
+
+        // Wait for completion
+        while (HOSTAR & 1) {}
+        // Clear status
+        HOSTAR = HOSTAR;
+
+        // Enable PECI, clearing data fifo's
+        HOCTLR = (1 << 5) | (1 << 3);
+        // Set address to default
+        HOTRADDR = 0x30;
+        // Set write length
+        HOWRLR = 1;
+        // Set read length
+        HORDLR = 2;
+        // Set command
+        HOCMDR = 1;
+        // Start transaction
+        HOCTLR |= 1;
+
+        // Wait for completion
+        while (HOSTAR & 1) {}
+
+        if (HOSTAR & (1 << 1)) {
+            // Use result if finished successfully
+            uint8_t low = HORDDR;
+            uint8_t high = HORDDR;
+            peci_offset = ((int16_t)high << 8) | (int16_t)low;
+
+            peci_temp = PECI_TEMP(T_JUNCTION) + peci_offset;
+            peci_duty = fan_duty(peci_temp);
+        } else {
+            // Default to 50% if there is an error
+            peci_offset = 0;
+            peci_temp = 0;
+            peci_duty = PWM_DUTY(50);
+        }
+    } else {
+        // Turn fan off if not in S0 state
+        peci_offset = 0;
+        peci_temp = 0;
+        peci_duty = PWM_DUTY(0);
+    }
+
+    uint8_t heatup_duty = fan_heatup(peci_duty);
+    uint8_t cooldown_duty = fan_cooldown(heatup_duty);
+    if (cooldown_duty != DCR2) {
+        DCR2 = cooldown_duty;
+        DEBUG("PECI offset=%d, temp=%d = %d\n", peci_offset, peci_temp, cooldown_duty);
+    }
+}