hw/adc: Add an ADC module for NPCM7XX

The ADC is part of NPCM7XX Module. Its behavior is controled by the
ADC_CON register. It converts one of the eight analog inputs into a
digital input and stores it in the ADC_DATA register when enabled.

Users can alter input value by using qom-set QMP command.

Reviewed-by: Havard Skinnemoen <hskinnemoen@google.com>
Reviewed-by: Tyrone Ting <kfting@nuvoton.com>
Signed-off-by: Hao Wu <wuhaotsh@google.com>
Message-id: 20210108190945.949196-4-wuhaotsh@google.com
[PMM: Added missing hw/adc/trace.h file]
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

2 files changed, 71 insertions, 0 deletions

diff --git a/include/hw/adc/npcm7xx_adc.h b/include/hw/adc/npcm7xx_adc.h
new file mode 100644
index 0000000000..7d8442107a
--- /dev/null
+++ b/include/hw/adc/npcm7xx_adc.h
@@ -0,0 +1,69 @@
+/*
+ * Nuvoton NPCM7xx ADC Module
+ *
+ * Copyright 2020 Google LLC
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * for more details.
+ */
+#ifndef NPCM7XX_ADC_H
+#define NPCM7XX_ADC_H
+
+#include "hw/clock.h"
+#include "hw/irq.h"
+#include "hw/sysbus.h"
+#include "qemu/timer.h"
+
+#define NPCM7XX_ADC_NUM_INPUTS      8
+/**
+ * This value should not be changed unless write_adc_calibration function in
+ * hw/arm/npcm7xx.c is also changed.
+ */
+#define NPCM7XX_ADC_NUM_CALIB       2
+
+/**
+ * struct NPCM7xxADCState - Analog to Digital Converter Module device state.
+ * @parent: System bus device.
+ * @iomem: Memory region through which registers are accessed.
+ * @conv_timer: The timer counts down remaining cycles for the conversion.
+ * @irq: GIC interrupt line to fire on expiration (if enabled).
+ * @con: The Control Register.
+ * @data: The Data Buffer.
+ * @clock: The ADC Clock.
+ * @adci: The input voltage in units of uV. 1uv = 1e-6V.
+ * @vref: The external reference voltage.
+ * @iref: The internal reference voltage, initialized at launch time.
+ * @rv: The calibrated output values of 0.5V and 1.5V for the ADC.
+ */
+typedef struct {
+    SysBusDevice parent;
+
+    MemoryRegion iomem;
+
+    QEMUTimer    conv_timer;
+
+    qemu_irq     irq;
+    uint32_t     con;
+    uint32_t     data;
+    Clock       *clock;
+
+    /* Voltages are in unit of uV. 1V = 1000000uV. */
+    uint32_t     adci[NPCM7XX_ADC_NUM_INPUTS];
+    uint32_t     vref;
+    uint32_t     iref;
+
+    uint16_t     calibration_r_values[NPCM7XX_ADC_NUM_CALIB];
+} NPCM7xxADCState;
+
+#define TYPE_NPCM7XX_ADC "npcm7xx-adc"
+#define NPCM7XX_ADC(obj) \
+    OBJECT_CHECK(NPCM7xxADCState, (obj), TYPE_NPCM7XX_ADC)
+
+#endif /* NPCM7XX_ADC_H */
diff --git a/include/hw/arm/npcm7xx.h b/include/hw/arm/npcm7xx.h
index 5469247e38..51e1c7620d 100644
--- a/include/hw/arm/npcm7xx.h
+++ b/include/hw/arm/npcm7xx.h
@@ -17,6 +17,7 @@
 #define NPCM7XX_H
 
 #include "hw/boards.h"
+#include "hw/adc/npcm7xx_adc.h"
 #include "hw/cpu/a9mpcore.h"
 #include "hw/gpio/npcm7xx_gpio.h"
 #include "hw/mem/npcm7xx_mc.h"
@@ -76,6 +77,7 @@ typedef struct NPCM7xxState {
     NPCM7xxGCRState     gcr;
     NPCM7xxCLKState     clk;
     NPCM7xxTimerCtrlState tim[3];
+    NPCM7xxADCState     adc;
     NPCM7xxOTPState     key_storage;
     NPCM7xxOTPState     fuse_array;
     NPCM7xxMCState      mc;