it8380dev: add adc control module

Add adc control module for emulation board.
The ADC converts the input voltage signal ranging
from 0v to 3v into a 10-bit unsigned integer.

Signed-off-by: Dino Li <dino.li@ite.com.tw>

BRANCH=none
BUG=none
TEST=manual test.
1 - adc channel 1, 3, 5, and 7 to ground.
2 - adc channel 0 and 2 to 1.26v.
3 - adc channel 4 and 6 to 1.72v.
4 - condition, factor_mul = 3000, factor_div = 1024, and shift = 0.
5 - console "adc", result as following.
adc_ch0 = 1256
adc_ch1 = 0
adc_ch2 = 1256
adc_ch3 = 0
adc_ch4 = 1722
adc_ch5 = 0
adc_ch6 = 1725
adc_ch7 = 0

Change-Id: I72efd09c9f7dbff25c4f6fd4846c9b1c1e5637ca
Reviewed-on: https://chromium-review.googlesource.com/228092
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>
Commit-Queue: Dino Li <dino.li@ite.com.tw>
Tested-by: Dino Li <dino.li@ite.com.tw>

1 files changed, 171 insertions, 0 deletions

diff --git a/chip/it83xx/adc.c b/chip/it83xx/adc.c
new file mode 100644
index 0000000000..bb59bda0ff
--- /dev/null
+++ b/chip/it83xx/adc.c
@@ -0,0 +1,171 @@
+/* Copyright (c) 2014 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+/* IT8380 ADC module for Chrome EC */
+
+#include "adc.h"
+#include "adc_chip.h"
+#include "clock.h"
+#include "console.h"
+#include "common.h"
+#include "gpio.h"
+#include "hooks.h"
+#include "registers.h"
+#include "task.h"
+#include "timer.h"
+#include "util.h"
+
+/* Data structure of ADC channel control registers. */
+const struct adc_ctrl_t adc_ctrl_regs[] = {
+	{&IT83XX_ADC_VCH0CTL, &IT83XX_ADC_VCH0DATM, &IT83XX_ADC_VCH0DATL,
+		&IT83XX_GPIO_GPCRI0},
+	{&IT83XX_ADC_VCH1CTL, &IT83XX_ADC_VCH1DATM, &IT83XX_ADC_VCH1DATL,
+		&IT83XX_GPIO_GPCRI1},
+	{&IT83XX_ADC_VCH2CTL, &IT83XX_ADC_VCH2DATM, &IT83XX_ADC_VCH2DATL,
+		&IT83XX_GPIO_GPCRI2},
+	{&IT83XX_ADC_VCH3CTL, &IT83XX_ADC_VCH3DATM, &IT83XX_ADC_VCH3DATL,
+		&IT83XX_GPIO_GPCRI3},
+	{&IT83XX_ADC_VCH4CTL, &IT83XX_ADC_VCH4DATM, &IT83XX_ADC_VCH4DATL,
+		&IT83XX_GPIO_GPCRI4},
+	{&IT83XX_ADC_VCH5CTL, &IT83XX_ADC_VCH5DATM, &IT83XX_ADC_VCH5DATL,
+		&IT83XX_GPIO_GPCRI5},
+	{&IT83XX_ADC_VCH6CTL, &IT83XX_ADC_VCH6DATM, &IT83XX_ADC_VCH6DATL,
+		&IT83XX_GPIO_GPCRI6},
+	{&IT83XX_ADC_VCH7CTL, &IT83XX_ADC_VCH7DATM, &IT83XX_ADC_VCH7DATL,
+		&IT83XX_GPIO_GPCRI7},
+};
+
+static void adc_enable_channel(int ch)
+{
+	if (ch < 4)
+		/*
+		 * for channel 0, 1, 2, and 3
+		 * bit4 ~ bit0 : indicates voltage channel[x]
+		 *               input is selected for measurement (enable)
+		 * bit 7 : W/C data valid flag
+		 */
+		*adc_ctrl_regs[ch].adc_ctrl = 0x80 + ch;
+	else
+		/*
+		 * for channel 4, 5, 6, and 7
+		 * bit4 : voltage channel enable (ch 4~7 only)
+		 * bit7 : W/C data valid flag
+		 */
+		*adc_ctrl_regs[ch].adc_ctrl = 0x90;
+
+	/* bit 0 : adc module enable */
+	IT83XX_ADC_ADCCFG |= 0x01;
+}
+
+static void adc_disable_channel(int ch)
+{
+	if (ch < 4)
+		/*
+		 * for channel 0, 1, 2, and 3
+		 * bit4 ~ bit0 : indicates voltage channel[x]
+		 *               input is selected for measurement (disable)
+		 * bit 7 : W/C data valid flag
+		 */
+		*adc_ctrl_regs[ch].adc_ctrl = 0x9F;
+	else
+		/*
+		 * for channel 4, 5, 6, and 7
+		 * bit4 : voltage channel disable (ch 4~7 only)
+		 * bit7 : W/C data valid flag
+		 */
+		*adc_ctrl_regs[ch].adc_ctrl = 0x80;
+
+	/* bit 0 : adc module disable */
+	IT83XX_ADC_ADCCFG &= ~0x01;
+}
+
+int adc_read_channel(enum adc_channel ch)
+{
+	/* voltage 0 ~ 3v = adc data register raw data 0 ~ 3FFh (10-bit ) */
+	uint16_t adc_raw_data;
+	int num;
+	int adc_ch;
+
+	adc_ch = adc_channels[ch].channel;
+
+	adc_enable_channel(adc_ch);
+
+	/* Maximum time for waiting ADC conversion is ~1.525ms */
+	for (num = 0x00; num < 100; num++) {
+		/* delay ~15.25us */
+		IT83XX_GCTRL_WNCKR = 0;
+
+		/* data valid of adc channel[x] */
+		if (IT83XX_ADC_ADCDVSTS & (1 << adc_ch)) {
+			/* read adc raw data msb and lsb */
+			adc_raw_data = (*adc_ctrl_regs[adc_ch].adc_datm << 8) +
+				*adc_ctrl_regs[adc_ch].adc_datl;
+
+			/* W/C data valid flag */
+			IT83XX_ADC_ADCDVSTS = (1 << adc_ch);
+
+			adc_disable_channel(adc_ch);
+			return adc_raw_data * adc_channels[ch].factor_mul /
+				adc_channels[ch].factor_div +
+				adc_channels[ch].shift;
+		}
+	}
+
+	adc_disable_channel(adc_ch);
+	return ADC_READ_ERROR;
+}
+
+int adc_read_all_channels(int *data)
+{
+	int index;
+
+	for (index = 0; index < ADC_CH_COUNT; index++) {
+		data[index] = adc_read_channel(index);
+		if (data[index] == ADC_READ_ERROR)
+			return EC_ERROR_UNKNOWN;
+	}
+	return EC_SUCCESS;
+}
+
+/*
+ * ADC analog accuracy initialization (only once after VSTBY power on)
+ *
+ * Write 1 to this bit and write 0 to this bit immediately once and
+ * only once during the firmware initialization and do not write 1 again
+ * after initialization since IT8380 takes much power consumption
+ * if this bit is set as 1
+ */
+static void adc_accuracy_initialization(void)
+{
+	/* bit3 : start adc accuracy initialization */
+	IT83XX_ADC_ADCSTS |= 0x08;
+	/* short delay for adc accuracy initialization */
+	IT83XX_GCTRL_WNCKR = 0;
+	/* bit3 : stop adc accuracy initialization */
+	IT83XX_ADC_ADCSTS &= ~0x08;
+}
+
+/* ADC module Initialization */
+static void adc_init(void)
+{
+	int index;
+	int ch;
+
+	/* ADC analog accuracy initialization */
+	adc_accuracy_initialization();
+
+	for (index = 0; index < ADC_CH_COUNT; index++) {
+		ch = adc_channels[index].channel;
+
+		/* enable adc channel[x] function pin */
+		*adc_ctrl_regs[ch].adc_pin_ctrl = 0x00;
+	}
+
+	/* bit 5 : ADCCTS0 = 1 */
+	IT83XX_ADC_ADCCFG = 0x20;
+
+	IT83XX_ADC_ADCCTL = 0x04;
+}
+DECLARE_HOOK(HOOK_INIT, adc_init, HOOK_PRIO_DEFAULT);